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13-073 Storm Dranage, Improvements to Rockrige 25 coles meadow rd.STORM DRAINAGE ANALYSIS AND DESIGN for the proposed improvements to "Rockridge at Laurel Park" on 25 Coles Meadow Road Northampton, Massachusetts 01060 Prepared For. New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 Project No. 60- 155.00 01P KELLEY IF 3 Prepared by. Coler & Colantonio, Inc. 1 Sugarloaf Street South Deerfield, MA 01373 Tel: (413) 665 -5300 Fax: (413) 665 -5390 March 5, 2003 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 STORM DRAINAGE ANALYSIS AND DESIGN for the proposed improvements to "Rockridge at Laurel Park" 25 Coles Meadow Road in Northampton, Massachusetts 1.0 INTRODUCTION Coler & Colantonio, Inc. has prepared this drainage analysis and design for the proposed improvements to the "Rockridge at Laurel Park" assisted living facility in Northampton, Massachusetts. The property is shown on Assessor's Map 13, Lot 073 and is owned and operated by New England Deaconess Association of Concord, Massachusetts. The existing 11.09± acre site is located at the intersection of Coles Meadow Road and North King Street, adjacent to the Massachusetts State Police barracks. The property is bounded on the North and West by land of the Laurel Park Association, on the East by North King Street, and on the South by Coles Meadow Road (refer to project locus in -- Appendix 1). The project proposes the expansion and redevelopment of the Rockridge assisted living facility with improvements to the access drive, parking, sidewalks, utilities, landscaping, and a closed- conveyance drainage system with underground stormwater detention system. The proposed expansion includes construction of a three -story building and twelve one -story cottages with carports. The improvments will add 19 congregate assited living units and 12 attached elderly housing cottages to the existing site for a grand total of approximately 88 units. The existing main access drive has been lengthened and terminates in a cul -de -sac near the new entrance. A new driveway across from the existing parking area has been proposed to access the one - bedroom cottages and terminates in an emergency hammer -head style turnaround. New parking areas have been added for visitors and staff near the main entrance and service entrances. Independent water and sewer connections have been proposed from Coles Meadow Road to serve the new facility. The property is located in the suburban residential district (SR) within the planned village overlay. The surrounding areas along North King Street support a variety of mixed residential and commercial uses. The proposed site is previously developed and consists of an existing three - story/one -story combination building with gross floor area of approximately 38,800 sf (14,500 sf ± in plan area) and a parking lot for 44 vehicles. There are two existing access points to the site; one on North King Street used for deliveries and staff, the other off of Coles Meadow Road is the main entrance and includes visitor - parking areas. A gravel access drive extends from the main entrance to Laurel Park and serves primarily as a secondary access to that facility. Topographic relief across the existing site is on the order of 32 feet. The site is nearly level near North King Street and climbs moderately from the main entrance to the western property line near Coles Meadow Road. The northeastern portion of the site 4 -- contains two separate narrow bands of bordering vegetated wetlands separated by small New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 ridge. The tributary drainage area is approximately 14.91 acres and encompasses the land between the property line and Coles Meadow Road to the West. The purpose of this report is to compare the existing drainage conditions with the proposed conditions relative to the down gradient runoff generated by proposed improvements. Stormwater management will be provided according to policy established by the Massachusetts Department of Environmental Protection "Stormwater Management" Volumes 1 and 2 issued March 1997 and the current City of Northampton Site Plan approval regulations. The proposed facility provides a conservative approach to the _ development of the site through a careful design that will match or provide less impact as compared to the pre - development conditions. The project has been designed to mitigate for impacts to the 2 -year, 10 -year, and 25 -year storm events. The 100 -year storm event has been evaluated against adverse impact to downstream properties and will not substantially increase off -site flooding impacts. The closed- conveyance drainage system has been designed with deep sump catch basins, water quality inlets, smooth - walled HDPE, and Corrugates Steel Pipe (CSP) to collect and direct the surface water from the newly developed and existing impervious areas to a series of corrugated steel pipe underground storage tanks. Existing stormwater controls have been retrofitted and upgraded to the extent practicable and feature a Stormceptor® water quality inlet to treat the runoff from the service parking area. The existing 44 car parking area has been rerouted into the new conveyance system for treatment of suspended solids and detention prior to controlled release. The stormwater management system has been designed to minimize the volume, rate of discharge, control erosion and sedimentation, provide for recharge of groundwater, and reduce the runoff characteristics for the 2 -year, 10 -year, and 25 -year storm events. The proposed improvements are shown on the plans entitled "Proposed Site Improvements, Rockridge at Laurel Park, Coles Meadow Road and North King Street, Northampton, Massachusetts ", dated March 6, 2003 as prepared by Coler & Colantonio, Inc., 1 Sugarloaf Street, South Deerfield, MA 01373. 1.1 METHODOLOGY HydroCAD Stormwater Modeling System computer program by Applied Microcomputer Systems was used to develop stormwater runoff rates and volumes for the existing and proposed conditions at the project site. The software uses Soil Conservation Service (SCS) methodology. The SCS method is based on rainfall observations that were used to develop the Intensity- Duration - Frequency relationship or IDF curve. By studying the Weather Bureau's Rainfall Frequency Atlases, the SCS determined that four "mass curves" could be used to represent the characteristics of the rainfall distribution throughout the country. The mass curve is a dimensionless distribution of rainfall over time, which indicates the fraction of the rainfall event that occurs at a given time within a 24 -hour precipitation event. This synthetic distribution develops peak rates for storms of varying durations and intensities. The SCS distribution provides a cumulative rainfall at any point in time and allows volume dependent routing runoff calculations to occur. �- The HydroCAD software is a hydrograph generation and routing program similar to TR -20. Both programs utilize the SCS methodology. The HydroCAD software has the 2 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 additional capability to describe shallow concentrated flow. The "NEH -4 Upland Method" included in the HydroCAD software is applicable for conditions which occur in the headwaters of a watershed up to 2000 acres. The NEH -4 Upland Method allows the Time of Concentration (T,) to reflect ground conditions such as overland flow, grassed waterways, paved areas and upland gullies. The T is the time required for water to flow from the most distant point on a runoff area to the measurement or collection point. This -- results in a model that more accurately reflects the ground surface for shallow concentrated flow conditions, than TR -20 which is limited to distinguishing only paved and unpaved surfaces. In instances where the watersheds are small and impervious, Tc has been directly entered as a 5- minute minimum. This is consistent with the Rational Method, TR -55 Urban Hydrology for Small Watersheds, and standard engineering practice. The lower boundary of 5 minutes will yield a conservative, yet practical measure of stormwater runoff flow. 1.2 SOIL MORPHOLOGY Soils are grouped according to their potential runoff characteristics. Soils are assigned to four groups, A through D. Group A contains soils with high infiltration rates -- when thoroughly wet and have low runoff potential. This group includes mainly sands and gravels consisting of deep, well to excessively drained media (sand, loamy sand or sandy loam). Group D, at the other end of the spectrum, has slow infiltration rates and high runoff potential. High water table, clay layers, and nearly impervious material are all characteristics associated with this group. A USDA Soil Conservation Service map can be found in the appendix indicating soils present on the project site according to the Soil Survey of Hampshire County Massachusetts, Central Part, December 1981. Soils throughout the site were classified into the following soil groups: Soil Group / Symbol Hydrologic Group Hinckley loamy sands (HgA) A Charlton sandy loamy -Rock Outcrop Hollis complex (CrC) 8 The Soil Conservation Service (SCS) defines Hinckley loamy sands as deep and excessively drained. The soils are formed in glacial outwash deposits and are commonly found on outwash plains, kames, and terraces. Typical profiles of these soils indicate a very dark grayish brown loamy sand about 8 inches thick, and a 21 -inch subsoil consisting of brown loamy and gravelly sand. The substratum extends to a depth of 60 inches or more and is classified as a loose brownish yellow stratified sand, coarse sand, gravelly sand, and gravel. Permeability of these soils is rapid in the subsoil and very rapid in the substratum. These soils are well suited to cultivated crops, hay, pasture, and on -site absorption systems. Hinckley soils are commonly found on level to gently sloping areas on the sides of hills, ridges, and small drainage ways. Approximately 40% of the total tributary drainage area or 5.96 acres± consists of the Hinckley series. The Charlton series consists of deep, well- drained soils on uplands formed in glacial till. This soil is commonly found on hills and the side slopes of small drainage ways. New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 A typical profile of Charlton soil is contained beneath wooded areas with a surface layer of about 7 inches containing dark fine sandy loam, a 15 inch thick subsoil of yellowish- brown, fine sandy loam and /or light -olive brown gravelly fine sandy loam, and an olive colored substratum that extends from a depth of 60 inches or more containing a massive, firm, gravelly sandy loam. Permeability of Charlton soil is moderately rapid in the subsoil and substratum. These soils are well- suited to trees and most areas are wooded. Slope is the main limitation of these soils for small commercial buildings and absorption fields. The remaining 60% of the tributary drainage area or approximately 8.95 acres± is Charlton soils. 1.3 DESIGN CRITERIA This drainage analysis was developed utilizing a Type III, 24 -hour storm as developed by the Soil Conservation Service. Two distinct design points were chosen at down gradient points in the drainage area to compare development conditions for each of the following storm frequencies. The design storm frequencies and corresponding rainfall depths were compiled from the "Atlas of Precipitation Extremes for the Northeastern United States and Southeastern Canada" and Technical Paper No. 40, Rainfall Frequency Atlas of the United States for Durations from 30 Minutes to 24 Hours and 1 to 100 Years" and have been estimated as follows: Storm Frequency (Years) 100 25 10 2 1.4 EXISTING CONDITIONS Rainfall Depth ( Inches 7.3 5.4 4.4 3.0 The project site consists of an existing three -story building with one -story addition and parking facilities for approximately 44 vehicles. All of the existing developments are confined to the southern end of the site along Coles Meadow Road and North King Street. The grounds around the facility consist of light woods and grassed areas. The remaining land to the North and East of the existing buildings is wooded uplands. The site is bisected by a bordering vegetated wetland and depression to the North of the existing facility. It was determined through site visits, aerial photography, and soil surveys that the majority of the site is woods, lawn, and woods /lawn mix in good condition. The tributary drainage area has a weighted average CN value of 57. The attached Existing Drainage Plan in Appendix C delineates the watersheds for the project and has been divided into two distinct design points for runoff comparison. Design Point 1 is the area tributary to the 24" Box Culvert that passes under Route 5 &10 (North King Street) and eventually travels into the Interstate 91 drainage system. Design Point 2 is the area tributary to the 30" twin culverts to the extreme North of the site. This design point remains unchanged in the post drain condition as no improvements are proposed within this watershed. A limited stormwater conveyance system is contained 4 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 -- onsite and routes two catch basins from the main parking area under the building to the northeast side where roof drains from the existing facility and a catch basin in the service parking area terminate into an 12" RCP outfall. The outfall travels to an area upstream of Design Point#1. There appears to be no existing infiltration or water quality BMP's utilized in the current layout. The 100 -year storm was routed through the existing facility for illustrative purposes only. The *HydroCAD model confirms that this limited system cannot handle the expected flows from this storm event. * (see summary Section 1.7) 1.5 PROPOSED CONDITIONS The Applicant proposes to construct a three -story addition to the existing facility including twelve one - bedroom cottages with a new building footprint area of approximately 0.67 acres. The associated site improvements include driveways, parking facilites, site utilities, ADA compliant walkways, landscaping, and a state -of- the -art underground stormwater management facility utilizing innovative treatment technologies. The existing entrance drive will be enlarged and extended to provide access to the new addition. A new internal driveway will stem from the existing access drive to provide vehicular entry to the cottages. Additional parking, including private parking areas and carports for the cottages -- will be incorporated into the site design to provide parking areas for approximately 90 total vehicles. Pedestrian access will be achieved through a system of lighted asphalt walks and features a wooded park and formal garden area. The service area entrance will be reconfigured and enlarged to provide parking spaces for staff including relocation of a storage building from the south side of the facility. A boardwalk and footpath will be constructed to provide access across the bordering wetland, making the existing community garden site accessible to the residents of the assisted - living facility. Impervious pavement areas will increase by approximately 1.1 acres have reduced calculated open space from 89% to 71 %. The attached Proposed Drainage Plan contains the subcatchments for each tributary watershed. The weighted average CN value for the tributary watershed has increased to 63. The closed- conveyance stormwater management system consists of smooth - walled �- high- density polyethylene (HDPE) and corrugated steel drain pipe (CSP) connected between a series of precast manholes and deep sump hooded catch basins. The proposed underground detention facility is fabricated from perforated 60" diameter aluminized type 2 corrugated steel pipe (CSP) with 3 "x1" corrugations (12 ga.) to provide the required detention volume. The underground stormwater management facility is backfilled with W angular crushed stone and wrapped with an engineered non -woven filter fabric to provide additional storage area and to facilitate infiltration into the surrounding soils. 36" diameter CSP connects the facility to a 30" diameter riser outlet structure contained within a 72" diameter manhole to control release rates of various design storms. The proposed stormwater management detention structure outlets to a level spreader to dissapate energy and control erosion. The existing 12" metal pipe /RCP drainage system and outlet will continue to convey roof runoff from the existing three -story building. To guard against possible impacts from the proposed, erosion and sedimentation control measures will be incorporated into the sequence of construction. This will include both modified construction procedures and temporary construction installations to control �- the movement of sediment into protected areas. Upon completion of all work, restoration and stabilization of disturbed areas will commence. Erosion /sedimentation control New England Deaconess Association s0 Deaconess Road Concord, Massachusetts 01742 installations include placement of hay bales and filter - fabric fencing around disturbed areas and at storm drainage inlet points. On -going stabilization of disturbed areas will be completed as the work progresses. Restoration/stabilization measures include seeding, mulching, and placement of stabilization fabric where required. These controls will be removed once a good vegetative cover is established and is accepted by the Northampton Conservation Commission. The proposed drainage improvements have been designed to meet the City of Northampton site plan approval requirements as well as the Massachusetts Department of Environmental Protection's Stormwater Management Policy. The stormwater conveyance and detention system has been designed to mitigate the increases in the peak rates of runoff from the site for the 2 -year, 10 -year, and 25 -year 24 -hour design storm events. The 100 -year design storm has been evaluated for the site and exceeds the flow of the pre - development condition *, but does not appear to affect downstream properties. 1.6 SUMMARY OF RESULTS AND CALCULATIONS The stormwater management for the proposed project includes: stormwater collection, treatment, and infiltration systems. These proposed mitigation measures were designed in accordance with the Massachusetts Department of Environmental Protection "Stormwater Management Volume 1 & 2, the Vortech® stormwater system, and the Stormceptor® system. In accordance with these regulations and standard engineering practice, the potential impacts of this project on downstream properties are mitigated and summarized in the tables below. The following is a summary of the calculation results for runoff encompassing the areas tributary to the Rockridge at Laurel Park improvements for the 2 -year, 10 -year, 25- year, and 100 -year design storm events. Detailed routing and volume calculations can be found in various sections appended to this narrative. Existing 7 Conditions Summary Design Point 1 - 24" Box Culvert *Design Point 2120 - Twin 30" Culverts ` 2- r 10- r 3.0 2.16 0.356 0.01 0.003 4.4 8.33 0.950 0.19 0.040 25- r 5.4 13.30 1.493 0.61 0.089 100-yr 7.3 # 22.65 # 2.726 2.41 0.220 1J New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 Proposed Conditions Summary Design Point 10 - 24" Box Culvert UNMITIGATED UNMITIGATED -MITIGATED Wifty a a +a R 2. r 3.0 ,x.,:, 6.94 0.724 1.90 0.403 10- r 4.4 14.57 1.477 7.00 1.082 25- r 5.4 21.47 2.116 11.97 1.688 1 00- r 7.3 36.70 3.486 34.09 3.005 Notes: * Design Point #2 is identical to Design Point #20. No improvements are proposed in the area tributary to this point, therefore no comparison between existing and proposed is warranted. ** Mitigated runoff rates and volumes as shown include the benefit of BMP's, Detention, and Infiltration Measures. # The 100 -year storm values as shown are for illustrative purposes only. The HydroCAD model for the existing storm drainage condition indicates that the current system cannot handle this storm event. The tables above indicate that peak rates have remained consistent or decreased between post- drainage and pre- drainage conditions when summed at the design points down gradient of the site. The new stormwater system conveyances will not discharge untreated runoff into any resource or buffer areas and have been designed to infiltrate into the surrounding soils through partial exfiltration in the underground stormwater management system. A presumed increase in runoff is shown for the 100 -year post condition at Design Point 10. The 100 -year storm is conveyed through a 30" horizontal orifice emergency outfall emptying into the wetland upstream of the 24" square box culvert. The existing 12" RCP outfall has been retained to convey clean roof runoff from the existing three -story building to the wetland. The groundwater recharge volume for this site has been calculated based upon type A and type B hydrologic soils. The overall tributary drainage area consists of a 60 -40 split for group B and A soils respectively. Only 5% of the proposed impervious area covers Type A soil. The recharge calculations have been adjusted to reflect a decrease in required volume to compensate for existing impervious areas. The adjusted recharge volume is calculated by reducing the total required recharge volume by the existing required volume to total 0.037 acre -feet or 1,600 cf. Groundwater recharge is achieved through partial exfiltration in the underground stormwater management system below the outlet structure and in the stone and perforated pipe infiltration trench near the main F New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 entrance. The 2ft x 3ft x145 ft long infiltration trench has been incorporated into the design to help convey snowmelt and runoff from Subcatchment 26. This area was removed from Subcatchment 3 to help reduce the burden of the existing drainage system and to increase the "dead storage" available for recharge. A total of approximately 1,600 cf of "dead ` storage is available for infiltration in these BMP's prior to any release. It is important to note that these BMP's will continue recharge to groundwater as flow rates increase above outlet inverts. The post- drainage conditions will not reduce groundwater recharge as compared to the existing site and should improve as much of the existing impervious areas have been directed towards the detention facility for partial infiltration. A long -term infiltration rate of 2.2 inches per hour or 0.003 feet per minute was estimated using the USDA soil classification of gravelly sandy loam and loamy sands presumed in the detention area. This infiltration rate is consistent with the rapid permeability in the substratum as listed in the USDA Soil Survey Engineering Properties and concurs with published permeability rates for Charlton (CrC) and Hinckley (HgA) soils ranging from 0.6 to 20 inches /hour. The depth to groundwater and long -term infiltration rate will be confirmed through exploratory borings scheduled in for building and foundation design. Treatment of stormwater runoff volume equal to 0.5 „ of rainfall over the proposed impervious areas tributary to the drainage area has been provided by the stormwater management system for the purpose of meeting water quality standards. An increase of 1.76 acres + of impervious area is proposed in the current layout (3.24a total - 1.48a existing = 1.76a). The total impervious area of 1.76 acres produces the required total volume of 0.073 acre -feet. A separate storm drainage conveyance system has been designed to covey approximately 0.67 acres (29,000 sf ±) of new clean roof runoff to the detention system for partial exfiltration. The actual volume to be treated has been reduced to 0.045 acre -feet or 1,960 cubic feet by factoring in the reduction of roof top runoff volume (1.76a - 0.67a =1.09a x 0.5” depth or 1,960 cf) because it is separated and conveyed separately to the stormwater management facility. The required water quality volume has been met through innovative technology by incorporating Stormceptor ® and VortechsTM treatment systems. These water quality inlets incorporate baffles, weirs, and hydrodynamic forces to enhance gravitational separation of floating and settling materials from stormwater flows without conventional sediment traps. The Stormceptor0 has been sized based upon proprietary software which calculates sediment removal efficiency based upon particle size distribution. The VortechsTm system has been specified as an off -line system that diverts low flows to the unit for treatment. Each system has a high flow by -pass to safely convey large, low probability storm events. The proposed stormwater management system has been designed to provide in excess of the required "calculated" 80% removal of Total Suspended Solids (TSS) tributary to the conveyance system on the proposed site per the Massachusetts D.E.P. Stormwater -- Management Policy. Discretionary street sweeping, deep sump catch basins, inlet Stormceptor0 and off -line Vortechs® systems have been utilized in the design to remove an average of 87% of the Total Suspended Solids (TSS) from the tributary site runoff. The performance of the Vortech® and Stormceptor0 systems have been verified by the Massachusetts Envirotechnology Partnership (STEP) and are approved for wide spread use. The effect of the underground detention facility was not factored into the calculations because the removal of accumulated sediment is more difficult than a conventional at- grade system. 8 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 The existing asphalt parking and service areas were retrofitted and routed through water quality inlets and detention facilities to further reduce impact from the site. A chart illustrating each proposed conveyance to the detention facility is provided in the supplemental calculations. The supporting calculations indicate that the proposed facilities are more than sufficient to mitigate the effects of the development on stormwater runoff quality entering the resource areas. 1.7 STORMWATER MANAGEMENT STANDARDS The following is an explanation on how the proposed project meets the Stormwater Management Standards as prepared by the MA Department of Environmental Protection -- and the MA Office of Coastal Zone Management. Please refer to the Stormwater Management Form in Appendix B. Untreated Stormwater (Standard 1) - No new stormwater system conveyances will discharge untreated runoff into the resource or buffer areas or cause erosion in the onsite wetlands. A closed- conveyance drainage system has been designed to direct stormwater runoff from the newly developed areas to Stormceptor0 and VortechsTM water quality inlets for pre- treatment prior to partial exfiltration of first flush runoff through the underground stormwater management system. A riprap outlet spreader will dissipate runoff energy from significant storm events before release into a wetland resource area. The wetland will transmit the clean runoff to the 24" Box Culvert eventually traveling into the Interstate 91 drainage system. Post- Development Peak Discharge Rates (Standard 2) — The peak discharge rates were calculated with the aid of a hydrograph routing program using TR -20 methodology. A multi -stage outlet structure has been sized to meet the run -off rates for the 2 -yr, 10 -yr and 25 -yr storm events and reduce the volume of runoff over unmitigated levels. The stormwater detention system will partially detain the 100 -year storm event to provide a buffer against off -site flooding impacts. A 30" diameter emergency overflow orifice has been incorporated into the outlet structure to convey the 100 -yr storm event. Exfiltration will occur in the underground stormwater management system after pre- treatment through deep sump catch basins and water quality inlets. Recharge to Groundwater (Standard 3) - The majority (95 %) of the impervious areas for the tributary drainage area are contained within Hydrologic Grouping B as shown on the drainage area maps. Recharge to groundwater will be provided through partial exfiltration in the underground stormwater management system and through a 145 -foot long infiltration trench. An exfiltration rate of 2.2 inch /hour (0.003 feet/minute) is utilized in the calculations and is consistent with sandy loam /loamy sand soils mapped onsite. The proposed -- development and expansion will not reduce groundwater recharge as compared to the existing site and will approximate current conditions to the extent feasible. Supplemental drainage calculations found in the appendix. Removal of 80% TSS (Standard 4) - The proposed stormwater management system has been designed to provide the required "calculated" removal of the Total Suspended Solids (TSS) for the conveyance system on the proposed site per the Massachusetts D.E.P. Stormwater Management Policy. Discretionary street sweeping, deep sump hooded catch 9 New England Deaconess Association 80 Deaconess Road .� Concord, Massachusetts 01742 basins, innovative water quality inlets, and a partial exfiltration detention facility has been utilized in the design to remove an average of at least 80% of the Total Suspended Solids (TSS) from the total site storm runoff. Large portions of the existing impervious parking and _ service areas have been captured and treated by the proposed system to provide an increase in treatment for the redeveloped portions of the site. A chart illustrating each proposed conveyance outfall is provided in the supplemental calculations. Land Uses with Higher Pollutant Loads (Standard 5) — The property is zoned suburban residential (SR) district within the planned village overlay. The proposed use as an assisted living facility is not considered a land use with high pollutant loads. Critical Areas (Standard 6) — The project is not located within a critical area as defined the Stormwater Management Policy. For the purposes of this design, an equivalent Water Quality Volume of 0.5" x new impervious area was maintained and treated through innovative technologies to preserve and protect the Bordering Vegetated Wetland resource areas and buffer zones. Redevelopment (Standard 7) — The project proposes a combination of redevelopment and new development on the site. The associated improvements have been designed with BMP's to the extent practicable to meet the performance standards in the Stormwater Management Policy including retrofitting and expanding the existing system to meet TSS removal, water quality, and mitigation of peak discharge rates. Erosion and Sediment Controls (Standard 8) — Staked hay bales and filter- fabric fencing will be used during construction as outlined in the Operation & Maintenance Plan and shown on the plan set. Direction of silt -laden runoff shall be directed towards vegetated areas, temporary sedimentation basins, and diversion swales. Operation and Maintenance Plan (Standard 9) — An Operation and Maintenance plan has been customized to fit the design of the proposed Rockridge site improvements. Provisions to maintain runoff control devices have been assured through structural, non- structural, and construction management approaches. Please see the attached O &M Plan. 1.8 CONCLUSION In conclusion, the results of this report indicate that the proposed stormwater management plan appears to meet all requirements of the City of Northampton and the Massachusetts Department of Environmental Protection's " Stormwater Management Policy" within the scope and parameters of the proposed project. 6— h.-- 10 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 STORMWATER OPERATION AND MAINTENANCE PLAN OWNER AND RESPONSIBLE PARTY: Construction Phase Activities: New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 Contact: Mr. Walter Bartkus, Director of Engineering Services Phone: (978) 369 -5151 Day -to -day Operation and Maintenance: -- Rockridge at Laurel Park 25 Coles Meadow Road Northampton, Massachusetts 01060 Contact: Mr. Walter Jones Phone: (413) 586 -2902 PROJECT OVERVIEW The proposed project includes construction of a three -story addition (37,500 sf gross floor area) to the existing facility plus 12 one - bedroom cottages and associated site improvements including parking facilites, paved access drives, utilities, landscaping, ADA compliant walkways, and a closed- conveyance stormwater management system. CONSTRUCTION MANAGEMENT A construction manager with adequate knowledge and experience on projects of similar size and scope shall be employed to oversee all sitework related construction. During construction, silt -laden runoff or discharge from dewatering operations (if necessary) will be prevented from entering wetlands and resource areas untreated. Siltation barriers consisting of a filter fabric silt fence, hay bales will be erected in advance of construction along the downstream edge of all disturbed areas and maintained throughout the construction period. Check dams will be used in temporary constructed drainage ways as necessary to reduce erosion. If dewatering is required during the construction, discharges may be directed toward vegetated areas for settlement of suspended solids. Outflow of silt -laden runoff shall not be permitted to flow directly into the wetlands or resource areas. Upon completion of site stabilization, the catch basins and existing conveyance system 11 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 shall be thoroughly cleaned of silt and sediment and made ready for the proposed operation. Siltation barriers, temporary settling basins, and diversion berms shall be constructed and inspected by the resident project Engineer on a monthly basis or as necessary, after any significant (0.5" or more) storm event and daily while dewatering operations are proceeding. Care should be taken when constructing stormwater control structures. Light earth - moving equipment shall be used to excavate in the vicinity of the infiltration areas. Use of heavy- equipment causes excessive compaction of the soils beneath the basin resulting in reduced infiltration capacity. At no time shall temporary infiltration areas or settling basins be constructed in the vicinity of the proposed infiltration system in order to prevent the soils from becoming clogged with sediment. NON- STRUCTURAL APPROACHES PARKING LOT /DRIVEWAY SWEEPING The property owner shall maintain a program of parking lot/driveway sweeping to reduce sediment accumulation in the deep sump catch basins. It is recommended that sweeping occur at least once in the fall and spring prior to cleaning and inspection of the catch basin and manhole structures. GRADING The impervious areas of the site shall be graded as gently as possible, generally not more than 4% or 5% slopes to reduce runoff velocities. Steep slopes will be permanently vegetated to dissipate energy and reduce potential erosion. No constructed vegetated slopes should exceed 2H:1V. Steep slopes may require soil reinforcement and additional vegetation. FLOW OVER VEGETATED AREAS Wherever possible, runoff from paved areas and snowmelt shall be directed over vegetated areas to promote settlement of suspended solids before entering a wetland or resource area. STRUCTURAL BEST MANAGEMENT PRACTICES DEEP SUMP CATCH BASINS, AREA DRAINS, AND MANHOLE STRUCTURES Catch basins shall be cleaned, in dry weather, when half of the sump capacity is filled or at a minimum of twice a year. Cleaning will take place at the completion of construction, in early spring after sanding of roadways has ceased, and in the fall. All manholes shall be inspected at least once annually. Any obstructions, sediment, `- and debris that could potentially cause clogs shall be removed within the 12 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 conveyance system as necessary. Inverts, grates, and hoods shall be checked and replaced as necessary to maintain hydraulic effectiveness. DETENTION FACILITY WITH PARTIAL EXFILTRATION The underground detention system has been designed with riser structures at grade to aid the removal of sediment and debris accumulating in the structure. The detention facility contains a multi -stage outlet structure to meet individual storm events. Once the system goes online, inspections should occur after each storm event for the first few months to ensure proper stabilization, function, and to ensure that the outlets remain free of obstructions. Preventative maintenance shall be performed at least twice per year and after every major storm event (> 1" of rainfall) and shall include removal of accumulated sediment, inspection of the detention structure, and monitoring of groundwater and infiltration rates to ensure proper operation of the system. Important items to check for include differential settlement, cracking, breakout, clogging of outlets and vents, and root infestation. Water levels should be checked and recorded against rainfall amounts to verify that the drainage system is working properly. ENERGY DISSAPATORS AND LEVEL SPREADERS During the construction phases of the project, the energy dissipaters and level spreaders that receive significant runoff shall be inspected monthly and cleaned as necessary and /or after major storms events (> 1" of rainfall). Thereafter, these structures will be cleaned at least twice per year, in the spring and fall, or as needed depending on the frequency of major storm events (> 1" of rainfall). The riprap shall be inspected, cleaned of sediment and debris, and reinstalled as necessary to maintain effectiveness. GRASS -LINED SWALES Swales shall be inspected on a semi - annual basis in the early spring and fall. Additional inspections shall be performed during the first few months after construction to ensure that adequate vegetation has been established. Regular maintenance shall include mowing, fertilizing, pruning, debris removal, and weed /pest control. Swales shall be mowed at least once per year to a minimum of 4 inches so as not to reduce the effectiveness of pollutant removal and energy dissipation. Accumulated sediment and debris shall be manually removed at least twice per year. WATER QUALITY INLETS -- Water quality inlets shall be inspected and cleaned in accordance with the manufacturer's recommendations. Documentation from the manufacturer is attached. 13 Stor cep Owner's Manual April 2000 The Stormceptor System is protected by one or more of the following patents: Canadian Patent No. 2,009,208 Canadian Patent No. 2,137,942 Canadian Patent No. 2,175,277 Canadian Patent No. 2,180,305 -- Canadian Patent No. 2,206,338 U.S. Patent No. 4,985,148 U.S. Patent No. 5,498,331 —' U.S. Patent No. 5,725,760 U.S. Patent No. 5,753,115 U.S. Patent No. 5,849,181 U.S. Patent No. 6,068,765 Australia 693.164 Australia 707,133 New Zealand 314,646 European Paten Treaty 95 307 996.9 The Stormceptor System for Stormwater Quality Improvement Congratulations! Your selection of a Stormceptor System means that you have chosen the most recognized and efficient stormwater oil/sediment separator available. Stormceptor is a pollution control device that protects our lakes, rivers and streams from the harmful effects of non -point source pollution. Please address any questions or concerns regarding the Stormceptor Systems to Stormceptor Canada Inc at 1- 800 -565 -4801 or visit our website at www.stormceptor.com. What is a Stormceptor? Stormceptor is a patented water quality structure that takes the place of a conventional manhole with in a storm drain system. Stormceptor removes free oil (TPH) and suspended solids (TSS) from stormwater preventing spills and non -point source pollution from entering downstream lakes and rivers. Key benefits of a Stormceptor include: • Capable of removing 50% to 80% of the total sediment load when properly applied as a source control for small areas • Removes free oil from stormwater during low flow conditions Will not scour or re- suspend trapped pollutants _ • Excellent spill control device for commercial and industrial developments • Easy to maintain (vacuum truck) • STORMCEPTOR clearly marked on the cover (excluding inlet designs) • Engineered and continually tested Vertical orientation therefore resulting in a smaller footprint Please Maintain Your Stormceptor To ensure long -term environmental protection through continual performance, Stormceptor must be -- maintained The need for maintenance is determined through inspection of the Stormceptor. Procedures for inspection are provided in this document. Maintenance of the Stormceptor is performed from the surface via vacuum truck. . If you require a list of contacts for cleaning your Stormceptor please call one -- of our Stormceptor offices or your nearest Stormceptor affiliate (affiliates listed in Appendix 1). Stormceptor How does Stormceptor Work? Stormceptor can be divided into two components: • Lower treatment chamber • Upper by -pass chamber Stormwater flows into the by -pass chamber via the storm drain pipe. Low flows are diverted into the treatment chamber by a weir and drop pipe arrangement. The treatment chamber is always full of water. Water flows up through the outlet pipe based on the head at the inlet weir, and is discharged back into the by -pass chamber downstream of the weir. The downstream section of the by -pass chamber is connected to the outlet storm drainpipe. Free oils and other liquids lighter than water will rise in the treatment chamber and become entrapped beneath the fiberglass insert since the outlet pipe is submerged. Sediment will settle to the bottom of the chamber by gravity. The circular design of the treatment chamber is critical to prevent turbulent eddy currents and to promote settling. During high flow conditions, stormwater in the by -pass chamber will flow overtop of the weir and be conveyed to the outlet storm drain directly. Water that overflows the weir creates a backwater effect on the outlet pipe (head stabilization between the inlet drop pipe and outlet riser pipe) ensuring that excessive flow will not be forced into the treatment chamber, which could scour or re- suspend the settled material. The by -pass is an integral part of Stormceptor since other oil/grit separators have been noted to scour during high flow conditions (Schueler and Shepp, 1993). Stormceptor Models and Identification Stormceptor is available in both concrete and fiberglass. There are currently nine different sizes available. A concrete Stormceptor is denoted by STC (e.g. STC6000) preceding the model number. A fiberglass Stormceptor is denoted by STA (e.g. STA6000) preceding the model number. In the concrete Stormceptor, a fiberglass insert separates the treatment chamber from the by -pass chamber. There is three insert designs: the "spool', the "disc" and the "inlet ". The different insert designs are illustrated in Figures 1, 2 and 3. These designs are easily distinguishable from the surface once the cover has been removed. In the "spool' design you will see one large 914 mm (36 ") opening in the center of the insert with two 200 mm (8 ") inspection ports located either vertically on the sides of the 914 mm (36 ") opening or horizontally on either side of the opening. There are three versions of the in -line disc insert: "single inlet/outlet", "multiple inlet" and "submerged ". In the "disc" design you will be able to see the inlet pipe, the drop pipe opening to the lower chamber, the weir, a 150 mm (6 ") oil inspection/cleanout pipe, a large 610 mm (24 ") riser pipe - opening offset on the outlet side of the structure, and the outlet pipe from the unit. The weir will be around the 610 mm (24 ") outlet pipe on the "multiple inlet" disc insert. The "submerged" disc insert has a higher weir and a second inlet drop pipe. In the "inlet" design you will be Stormceptor able to see the 305 mm (12") inlet drop pipe and 100 mm, (4") outlet riser pipe as well as a central 100mm, [4"] oil inspection/cleanout port. Maintenance from the surface by vacuum truck. Vacuum hose lowered through central opening in insert Spool Insert Concrete Stonnceptor - A Figure 1 "Spool" Insert Concrete Stormceptor 0 Stormceptot- Oil removal can be performed by vacuum truck through the oil inspection / cleanout pipe Disc Insert Figure 2 Single Inlet/Outlet "Disc" Insert Concrete Stormceptor Stormceptor Inlet Insert Figure 3 STC 300/450 Inlet Insert Sizes/Models Dimensions of the fiberglass and concrete Stormceptorg units are provided in Table 1. Values of invert to grade are provided later in this document for your site. The total depth for cleaning will be the sum of the depth from invert to grade and invert to the bottom of the unit. Table 1. Stormceptor Dimensions * Inlet Grate Model (US) Pipe Invert to Bottom of STA Stormceptor m (in.) Pipe Invert to Bottom of STC Stormceptor min.) 300 450 t O il Port r- 1.7 (68) 750 900 1.6 (64) 1.9 (74) 1000 1200 2.1 (81) 2.2 (86) 1500 1800 2.9 (115) 3.1 (122) 2000 2400 2.3 (89) 3.1 (122) 3000 le Removable Tee 4.0 (158) 4000 Maintenance 2.9 (113) Inlet Insert Figure 3 STC 300/450 Inlet Insert Sizes/Models Dimensions of the fiberglass and concrete Stormceptorg units are provided in Table 1. Values of invert to grade are provided later in this document for your site. The total depth for cleaning will be the sum of the depth from invert to grade and invert to the bottom of the unit. Table 1. Stormceptor Dimensions * Model (Metric) Model (US) Pipe Invert to Bottom of STA Stormceptor m (in.) Pipe Invert to Bottom of STC Stormceptor min.) 300 450 1.6 (64) 1.7 (68) 750 900 1.6 (64) 1.9 (74) 1000 1200 2.1 (81) 2.2 (86) 1500 1800 2.9 (115) 3.1 (122) 2000 2400 2.3 (89) 3.1 (122) 3000 3600 3.2 (127) 4.0 (158) 4000 4800 2.9 (113) 3.7 (146) 5000 6000 3.5 (138) 4.3 (170) 6000 7200 3.3 (128) 4.0 (158) Depths are approximate The capacities of the different Stormceptor units are provided in Table 2. Stormceptor Table 2. Stormceptor Capacities Model (Metric) Model (US) Sediment Capacity L (US gal) Oil Capacity L US gal) Total Holding Capacity L (US gal) 300 450 1275 (335) 325 (85) 1775 (470) 750 900 2460 (565) 915 280) 4325 (950) 1000 1200 3260 (845) 915 (280) 5125 (1230) 1500 1800 5660 1445) 915 (280) 7525 (1830) 2000 2400 6150 (1345) 2945 (880) 10925 (2495) 3000 3600 10415 (2600) 2945 (880) 15195 3750) 4000 4800 14060 (3475) 3490 (1025) 20180 (5020) 5000 6000 18510 (4550) 3490 1025) 24635 (6095) 6000 7200 23445 (5425) 4150 (1100) 31210 (7415) Identification Even if you do not have plans of your storm drain system you will be able to easily identify where the inline Stormceptor unit(s) (spool or disc insert) are since the name STORMCEPTOR is clearly embossed on the cover. You will be able to determine the location of "inlet" Stormceptor units with horizontal catch basin inlets by looking down the grate since the insert will be visible. The name Stormceptor is not embossed on the inlet models due to the variability of inlet grates used/approved across North America. Once you have found the unit, you may still be uncertain which model number it is. Comparing the measured depth from the water level (bottom of insert) to the bottom of the tank with Table l should help determine the size of the unit. Starting in 1996, a metal serial number tag has been affixed to the inside of the unit. The serial number has the model number written on it. If the unit does not have a serial number, or if there is any uncertainty regarding the size of the interceptor using depth measurements, please contact Stormceptor at 1 800 565- - 4801 and we will help you determine the size of a particular unit. What is the Maintenance Procedure? Maintenance of Stormceptor is performed using vacuum trucks. No entry into the unit is required for maintenance of the spool insert, inlet insert or the smaller disc inserts. Entry to the level of the disc insert may be required for servicing the larger disc insert models. DO NOT ENTER THE _ STORMCEPTOR CHAMBER unless you have the proper equipment, have been trained and are qualified to enter a confined space, as identified by local Occupational Safety and Health Regulations (e.g. Canada Occupational Safety and Health Regulations — SOR/86 -304). Without the proper equipment and _ training, entry into confined spaces can result in serious bodily harm and potentially death. Consult local, provincial, and/or state regulations to determine the requirements for confined space entry. Be aware that the insert may be slippery. In addition, be aware that some units do not have a safety grate to cover the outlet riser pipe that leads to the submerged, lower treatment chamber. Stormceptor The Vacuum Service Industry is a well - established sector of the service industry that cleans underground tanks, sewers and catch basins. Costs to clean a Stormceptor will vary based on the size of unit and transportation distances. The depth of oil in the interceptor can be determined by inserting a dipstick tube in the 150 mm (6 ") oil inspection/cleanout pipe ( "disc" design), or in the 914 mm (36 ") central access way ( "spool" design), or in the 100 mm (4 ") cleanout pipe ( "inlet" design). Similarly, the depth of sediment can be measured from the surface without entry into the Stormceptor via a dipstick tube equipped with a ball valve (Sludge Judge). This tube would be inserted in the central opening ( "spool" design) or in the 610 mm (24 ") opening ( "disc" design), or in the 100 mm (4 ") cleanout pipe ( "inlet" design). Maintenance should be performed once the sediment depth exceeds the guideline values provided in Table 3. For the "spool" design Stormceptor maintenance is performed through the large central 914 mm (36 ") diameter opening for both the oil and the sediment. In the "disc" design, oil is removed through the 150 mm (6") oil inspection/cleanout pipe and sediment is removed through the 610 mm (24 ") diameter outlet riser pipe. Alternatively, oil could be removed from the 610 mm (24 ") opening if water is removed from the lower chamber to lower the oil level to the level of the drop pipes. For the "inlet" design, maintenance is performed through the 305mm (12 ") inlet drop pipe for the sediment, and oil can be removed from the 100 mm (4 ") oil/inspection cleanout pipe. We recommend the following procedure to clean out the Stormceptor: 1. Check for oil (using a dipstick tube) 2. Remove any oil separately using a small portable pump 3. Decant the water from the unit to the sanitary sewer using a portable pump (prior approval is required from the sewer authority /municipality) 4. Remove the sludge from the bottom of the unit using a vacuum truck 5. Re -fill the Stormceptor with water where required by the local jurisdiction How Often Is Maintenance Required? Generally, annual maintenance is recommended but the required maintenance frequency will vary with the amount of pollution on your site (number of hydrocarbon spills, amount of sediment, etc.). It is recommended that the frequency of maintenance be increased or reduced based on local conditions. If the sediment load is high, maintenance may be required semi-annually. Conversely once the site has stabilized, maintenance may be required less frequently. Maintenance should be performed immediately after an oil spill or once the sediment depth in Stormceptor reaches the value specified in Table 3 based on the unit size. In the "disc" design and "inlet" design, any potential obstructions at the inlet can be observed from the surface. The "disc" insert has been designed as a platform to facilitate maintenance of the Stormceptor and the storm drain system. Stor•rnceptor Table 3. Sediment Depths Indicatin Re uired Maintenance Model (Metric) Model (US) Sediment Depth mm (in.) 300 450 200 (8) 750 900 200 ( 1000 1200 250 (10) 1500 1800 375 (15) 2000 2400 300 (12) 3000 3600 425 (17) 4000 4800 375(15 5000 6000 450 (18) 6000 7200 375 (15) What Should I do in the Event of an Oil Spill? Stormceptor is often implemented in areas where the potential for spills is great. Stormceptor should be cleaned immediately after a spill occurs by a licensed liquid waste hauler. You should also notify the appropriate regulatory agencies as required in the event of a spill. Disposal of the Trapped Material Removed from Stormceptor The requirements for the disposal of material from Stormceptor are similar to that of any other Best Management Practices (BMP). Local guidelines should be consulted prior to disposal of the separator contents. In most areas the sediment, once dewatered, can be disposed of in a sanitary landfill. It is not anticipated that the sediment would be classified as hazardous waste. In some areas, mixing the water with the sediment will create a slurry that can be discharged into a trunk sanitary sewer. In all disposal options, approval from the dsposal facility operator /agency is required. Petroleum waste products collected in Stormceptor (oil/chemical/fuel spills) should be removed by a licensed waste management company. What if I see an oil rainbow or sheen at the Stormceptor outlet? With a steady influx of water with high concentrations of oil, a sheen may be noticeable at the Stormceptor outlet. This may occur because a rainbow or sheen can be seen at very small oil concentrations (< 10 ppm). Stormceptor will remove over 95% of all free oil and the appearance of a sheen at the outlet with high influent oil concentrations does not mean that the unit is not working to this level of removal. In addition, if the influent oil is emulsified, the Stormceptor will not be able to remove it. -- The Stormceptor is designed for free oil removal and not emulsified or dissolved oil conditions. Stormceptor VORTECHS STORMWATER TREATMENT SYSTEM MAINTENANCE The Vortechs System should be inspected at regular intervals and maintained when necessary to ensure optimum performance. The rate at which the System collects pollutants will depend more heavily on site activities than the size of the unit, e.g., unstable soils or heavy winter sanding will cause the grit chamber to fill more quickly but regular sweeping will slow accumulation. Inspection Inspection is the key to effective maintenance and is easily performed. Vortechnics recommends ongoing quarterly inspections of the accumulated sediment. Pollutant deposition and transport may vary from year to year and quarterly inspections will help insure that Systems are cleaned out at the appropriate time. Inspections should be performed more often in the winter months in climates where sanding operations may lead to rapid accumulations, or in equipment washdown areas. It is very useful to keep a record of each inspection. A simple form for doing so is provided. The Vortechs System should be cleaned when inspection reveals that the sediment depth has accumulated to within six inches of the dry- weather water surface elevation. This determination _ can be made by taking 2 measurements with a stadia rod or similar measuring device; one measurement from the manhole opening to the top of the sediment pile and the other from the manhole opening to the water surface. The System should be cleaned out if the difference between the two measurements is six inches or less. Note to avoid underestimating the volume of sediment in the chamber, the measuring device must be lowered to the top of the sediment pile carefully. Finer, silty particles at the top of the pile typically offer less resistance to the end of the rod than larger particles toward the bottom of the pile. Cleaning Maintaining the Vortechs System is easiest when there is no flow entering the System. For this reason, it is a good idea to schedule the cleanout during dry weather. Cleanout of the Vortechs System with a vacuum truck is generally the most effective and convenient method of excavating pollutants from the System. If such a truck is not available, a "clamshell' grab may be used, but it is difficult to remove all accumulated pollutants with such devices. In Vortechs installations where the risk of large petroleum spills is small, liquid contaminants may not accumulate as quickly as sediment. However, an oil or gasoline spill should be cleaned out immediately. Motor oil and other hydrocarbons that accumulate on a more routine basis should be removed when an appreciable layer has been captured. To remove these pollutants, it may be preferable to use adsorbent pads since they are usually cheaper to dispose of than the oil water emulsion that may be created by vacuuming the oily layer. Trash can be netted out if you wish to separate it from the other pollutants. Accumulated sediment is typically evacuated through the manhole over the grit chamber. Simply remove the cover and insert the vacuum hose into the grit chamber. As water is evacuated, the water level outside of the grit chamber will drop to the same level as the crest of the lower aperture of the grit chamber. It will not drop below this level due to the fact that the bottom and sides of the grit chamber are sealed to the tank floor and walls. This "Water Lock" VORTECHS STORMWATER TREATMENT SYST feature prevents water from migrating into the grit chamber, exposing the bottom of the baffle wall. Floating pollutants will decant into the grit chamber as the water level there is drawn -- down. This allows most floating material to be withdrawn from the same access point above the grit chamber. If maintenance is not performed as recommended, sediment may accumulate outside the grit chamber. If this is the case, it may be necessary to pump out all chambers. It is a good idea to check for accumulation in all chambers during each maintenance event to prevent sediment build up there. Manhole covers should be securely seated following cleaning activities, to ensure that surface runoff does not leak into the unit from above. VORTECHS STORMWATER TREATMENT SYSTEM INSPECTION & MAINTENANCE LOG Model: 5000 Location: Anywhere, USA Date Water Depth to Sediment' Floatable Layer Thickness z Maintenance Performed Maintenance Personnel Comments 12/01/99 36" 0" N/A B. Johnson Installed 03/01/00 28" Sheen None B. Johnson Swept parking lot 06/01/00 24" She None 09/01/00 20" 1" Sorbent pads deployed to remove captured oil S. Riley Oil spill 12/01/00 12" Sheen None S. Riley 4/01/01 6" 0.5" Clean -out scheduled S. Riley Heavy floating debris 04/15/01 36" 0" Grit Chamber evacuated ACE Environmental Services Cleanout completed bAMPLih 1. The water depth to sediment is determined by taking two measurements with a stadia rod: one measurement from the manhole opening to the top of the sediment pile and the other from the manhole opening to the water surface. When the difference between the two measurements is six inches or less, the System should be cleaned out. 2. For optimum performance, the System should be cleaned out when the floating hydrocarbon layer accumulates to an appreciable thickness. In the event of a spill, the System should be cleaned immediately. VORTECHS STORMWATER TREATMENT SYSTEM INSPECTION & MAINTENANCE LOG Model: Location: Water Floatable Maintenance Maintenance Date Depth to Layer Performed Personnel Comments Sediment' Thickness s 1. The water depth to sediment is determined by taking two measurements with a stadia rod: one measurement from the manhole opening to the top of the sediment pile and the other from the manhole opening to the water surface. When the difference between the two measurements is six inches or less, the System should be cleaned out. 2. For optimum performance, the System should be cleaned out when the floating hydrocarbon layer accumulates to an appreciable thickness. In the event of a spill, the System should be cleaned immediately. U) (.0 O < cle) Y S/ T —D o LO <1 co U) co o N nCN), 60 -155 ROCKRIDGE PREF Type /// 24 -hr Rainfal ? = 3.00" Prepared by Coler & Colantonio, Inc. Page 3 HydroCAD®6 00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 1 S: AREA TRIB. NORTH & EAST PROJECT SITE Runoff = 0.63 cfs @ 12.49 hrs, Volume= 0.117 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description _ 5,384 98 Paved parking & drives 20,993 61 >75% Grass cover, Good, HSG B 7,620 58 Woods /grass comb., Good, HSG B `— 1,078 32 Woods /grass comb., Good, HSG A 1,788 85 Gravel roads, HSG B 285 98 Rock Outcrop 3,753 98 Paved roofs & driveways 38,882 90 Wetland, HSG A 64,594 30 Woods, Good, HSG A 143,464 55 Woods, Good, HSG B `— 9,057 78 Row crops, straight row, Good, HSG B 296,898 57 Weighted Average Tc Length (min) (feet) Velocity Capacity Description 9.1 70 0.0900 0.1 Sheet Flow, A -B Woods: Light underbrush n= 0.400 P2= 3.00" 0.9 75 0.0800 1.4 Shallow Concentrated Flow, B -C Woodland Kv= 5.0 fps 1.8 120 0.0500 1.1 Shallow Concentrated Flow, C -D `— Woodland Kv= 5.0 fps 1.5 85 0.0350 0.9 Shallow Concentrated Flow, D -E Woodland Kv= 5.0 fps 2.0 160 0.0700 1.3 Shallow Concentrated Flow, E -F Woodland Kv= 5.0 fps 1.5 45 0.0100 0.5 Shallow Concentrated Flow, F -G Woodland Kv= 5.0 fps 16.8 555 Total 60 -155 ROCKRIDGE PREF Type /// 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 5 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 2S: AREA TRIB. TO PROJECT SITE SOUTH Runoff = 0.01 cfs @ 15.36 hrs, Volume= 0.004 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description ` 3,041 98 Paved road & drives 15,543 39 >75% Grass cover, Good, HSG A 10,857 61 >75% Grass cover, Good, HSG B 23,120 32 Woods /grass comb., Good, HSG A 4,498 58 Woods /grass comb., Good, HSG B 2,591 98 Paved roofs 3,149 30 Woods, Good, HSG A `— 8,624 55 Woods, Good, HSG B 71,423 47 Weighted Average -- Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.0 75 0.0150 0.1 Sheet Flow, A -B -- Grass: Short n=0.150 P2=3.00" 4.7 200 0.0200 0.7 Shallow Concentrated Flow, B -C 0.001 Woodland Kv= 5.0 fps ` 13.7 275 Total C Subcatchment 2S: AREA TRIB. TO PROJECT SITE SOUTH Hydrograph Plot — Runoff 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 0.011 0.01 -- 0.01 0.009 0.008 0.008 0.007 0.007 0.006 0.006 `— 3 0.005 0.005 0.004 0.004 ` 0.003 0.003 0.002 0.002 ` 0.001 0.001 0.000 C Hydrograph Plot — Runoff 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24-hr Rainfall =3.00" Prepared by Coler & Colantonio, Inc. iPage 7 HydroCAD®6 00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 313/2003 Subcatchment 4S: MAIN BUILDING ROOF Runoff = 1.00 cfs @ 12.07 hrs, Volume= 0.075 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 14,850 98 Paved roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Roof Subcatchment 4S: MAIN BUILDING ROOF Hydrograph Plot 1 3 0 LL — Runoff 0 1 2 3 4 5 6 7 8 9 10 11 1z Is 14 10 io ii io is cJ Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 9 HydroCAD®6 00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 6S: AREA TRIB. TO NORTH EAST WETLAND AREA Runoff = 0.01 cfs @ 17.00 hrs, Volume= 0.003 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 10,650 61 >75% Grass cover, Good, HSG B 464 98 Paved roofs 15,471 90 Wetland, HSG A 4,375 67 Row crops, straight row, Good, HSG A 62,860 30 Woods, Good, HSG A 93,820 45 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 50 0.0200 0.1., Sheet Flow, A -B Cultivated: Residue >20% n= 0.170 P2= 3.00" 2.8 140 0.0280 0.8 Shallow Concentrated Flow, B -C Woodland Kv= 5.0 fps 9.2 190 Total Subcatchment 6S: AREA TRIB. TO NORTH EAST WETLAND AREA Hydrograph Plot Runoff H V O LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 11 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Reach DP 1: DESIGN POINT #1 - 24" BOX CULVERT Inflow = 2.16 cfs @ 12.28 hrs, Volume= 0.356 of Outflow = 2.16 cfs @ 12.28 hrs, Volume= 0.356 af, Atten= 0 %, Lag= 0.0 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Reach DP 1: DESIGN POINT #1 - 24" BOX CULVERT Hydrograph Plot 2.16 cfs F v 3 0 LL lM1111111111 Inflow — Outflow 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall =3.00" Prep ared by Coler & Colantonio, Inc. Page 13 H ydroCAD® 00 s/n 001012 © 1986 -2001 Applied Microcomputer S ystems 31 3/200 3 Pond 1 R: 12" RCP FROM EX. DMH TO WETLAND Inflow = 1.92 cfs @ 12.17 hrs, Volume= 0.235 of Outflow = 1.92 cfs @ 12.17 hrs, Volume= 0.234 af, Atten= 0 %, Lag= 0.0 min Primary = 1.92 cfs @ 12.17 hrs, Volume= 0.234 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 3 Peak Elev= 191.51' Storage= 9 cf Plug -Flow detention time= 0.1 min calculated for 0.234 of (100% of inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -fe (sq -ft 190.75 0 0 0 0 190.80 12 0 0 12 194.80 12 48 48 61 196.75 3 14 62 81 197.40 0 1 62 85 Primary OutFlow (Free Discharge) t--1 = Culvert # Routing Invert Outlet Devices 1 Primary 190.75' 12.0" x 92.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 189.50' S= 0.0136 'P n=0.012 Cc= 0.900 Pond 1R: 12" RCP FROM EX. DMH TO WETLAND Hvdrograph Plot Inflow Primary � H w V O LL. V 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 lb I/ 10 iy cJ Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall= 3.00" _ Prepared by Coler & Colantonio, Inc. Page 15 HydroCAD®6 00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Pond 3R: 10" RCP FROM EX. CB PARKING LOT TO EX. DMH Inflow = 0.29 cfs @ 12.11 hrs, Volume= 0.021 of Outflow = 0.29 cfs @ 12.11 hrs, Volume= 0.021 af, Atten= 1 %, Lag= 0.0 min Primary = 0.29 cfs @ 12.11 hrs, Volume= 0.021 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 2 Peak Elev= 190.93' Storage= 4 cf Plug -Flow detention time= 0.6 min calculated for 0.021 of (100% of inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -feet) (sq -ft 190.60 0 0 0 0 190.65 12 0 0 12 194.65 12 48 48 61 197.35 7 25 74 91 '— 198.10 0 2 75 99 198.60 285 48 123 384 -- Primary OutFlow (Free Discharge) 't--1 =Culvert # Routing Invert Outlet Devices 1 Primary 190.65' 10.0" x 75.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 189.15' S=0.0200'/' n=0.012 Cc= 0.900 '- Pond 3R: 10" RCP FROM EX. CB PARKING LOT TO EX. DMH Hydrograph Plot — Inflow — Primary H w V O LL 1--. v 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) N U) N �.. Cfl 0 a �a T T n cn cn co O 0 cn N c J ill ,d s U f9 N f9 U 7 60 -155 ROCKRIDGE PREF Type l/l 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 18 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 1S: AREA TRIB. NORTH & EAST PROJECT SITE Runoff = 3.51 cfs @ 12.29 hrs, Volume= 0.401 of Runoff by SCS TR - 20 method, UH =SCS, Time Span= 0.00 - 20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 5,384 98 Paved parking & drives 20,993 61 >75% Grass cover, Good, HSG B 7,620 58 Woods /grass comb., Good, HSG B 1,078 32 Woods /grass comb., Good, HSG A `- 1,788 85 Gravel roads, HSG B 285 98 Rock Outcrop 3,753 98 Paved roofs & driveways 38,882 90 Wetland, HSG A 64,594 30 Woods, Good, HSG A 143,464 55 Woods, Good, HSG B 9,057 78 Row crops, straight row, Good, HSG B 296,898 57 Weighted Average Tc Length Slope Velocity Capacity Description 9.1 70 0.0900 0.1 Sheet Flow, A -B Woods: Light underbrush n= 0.400 P2= 3.00" .- 0.9 75 0.0800 1.4 Shallow Concentrated Flow, B -C Woodland Kv= 5.0 fps 1.8 120 0.0500 1.1 Shallow Concentrated Flow, C -D Woodland Kv= 5.0 fps `- 1.5 85 0.0350 0.9 Shallow Concentrated Flow, D -E Woodland Kv= 5.0 fps 2.0 160 0.0700 1.3 Shallow Concentrated Flow, E -F �- Woodland Kv= 5.0 fps 1.5 45 0.0100 0.5 Shallow Concentrated Flow, F -G Woodland Kv= 5.0 fps _ 16.8 555 Total 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rain fall= 4.40" Prepared by Coler & Colantonio, Inc. Page 20 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 2S: AREA TRIB. TO PROJECT SITE SOUTH Runoff = 0.21 cfs @ 12.46 hrs, Volume= 0.039 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 3,041 98 Paved road & drives 15,543 39 >75% Grass cover, Good, HSG A 10,857 61 >75% Grass cover, Good, HSG B 23,120 32 Woods /grass comb., Good, HSG A `— 4,498 58 Woods /grass comb., Good, HSG B 2,591 98 Paved roofs 3,149 30 Woods, Good, HSG A 8,624 55 Woods, Good, HSG B 71,423 47 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.0 75 0.0150 0.1 Sheet Flow, A -B Grass: Short n=0.150 P2=3.00" 4.7 200 0.0200 0.7 Shallow Concentrated Flow, B-C Woodland Kv= 5.0 fps 13.7 275 Total Subcatchment 2S: AREA TRIB. TO PROJECT SITE SOUTH Hydrograph Plot 0 0 0 0 0 0 0 0 a 0 0 0 0 0 LL 0 0 0 0 0 0 0 0 0 — Runoff 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE PREF Type Ill 24 -hr Rainl`611= 4.40" Prepared by Coler & Colantonio, Inc. Page 22 HydroCAD®6 00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 4S: MAIN BUILDING ROOF Runoff = 1.47 cfs @ 12.07 hrs, Volume= 0.113 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 14,850 98 Paved roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Roof Subcatchment 4S: MAIN BUILDING ROOF Hydrograph Plot w v 3 0 U. — Runoff Time (hours) 60 -155 ROCKRIDGE PREF Type Ill 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 24 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 313/2003 Subcatchment 6S: AREA TRIB. TO NORTH EAST WETLAND AREA Runoff = 0.19 cfs @ 12.44 hrs, Volume= 0.040 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 10,650 61 >75% Grass cover, Good, HSG B 464 98 Paved roofs 15,471 90 Wetland, HSG A 4,375 67 Row crops, straight row, Good, HSG A 62,860 30 Woods, Good, HSG A 93,820 45 Weighted Average �- Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 50 0.0200 0.1 Sheet Flow, A -B Cultivated: Residue >20% n=0.170 P2=3.00" 2.8 140 0.0280 0.8 Shallow Concentrated Flow, B -C Woodland Kv= 5.0 fps 9.2 190 Total Subcatchment 6S: AREA TRIB. TO NORTH EAST WETLAND AREA Hydrograph Plot 0.; C 0. 0. 0. 0. 0. 0. 0. 0. -- 0. _O u 0. 0. 0. 0. 0. 0. 0. 0. 0. n 0.19 cfs 17 15 I1 .1 )9 )8 )7 )6 )5 )4 )3 )2 )1 n 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) - Runoff 60 -155 ROCKRIDGE PREF Type I// 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 26 HydroCAD®6 00 s/n 001012 © 1986 -2001 Applied Microcomputer Syste _ _ 3/3/2003 Reach DP 1: DESIGN POINT #1 - 24" BOX CULVERT Inflow = 8.33 cfs @ 12.25 hrs, Volume= 0.950 of Outflow = 8.33 cfs @ 12.25 hrs, Volume= 0.950 af, Atten= 0 %, Lag= 0.0 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Reach DP 1: DESIGN POINT #1 - 24" BOX CULVERT Hydrograph Plot 3 0 i 4-1 11 Inflow Outflow v 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 28 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Pond 1R: 12" RCP FROM EX. DMH TO WETLAND Inflow = 5.06 cfs @ 12.19 hrs, Volume= 0.510 of .... Outflow = 5.05 cfs @ 12.19 hrs, Volume= 0.510 af, Atten= 0 %, Lag= 0.1 min Primary = 5.05 cfs @ 12.19 hrs, Volume= 0.510 of 3 Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 3 0 Peak Elev= 193.04' Storage= 27 cf LL Plug -Flow detention time= 0.2 min calculated for 0.509 of (100% of inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -feet) (sq -ft) 190.75 0 0 0 0 190.80 12 0 0 12 194.80 12 48 48 61 196.75 3 14 62 81 197.40 0 1 62 85 Primary OutFlow (Free Discharge) 't-1 =Culvert # Routing Invert Outlet Devices 1 Primary 190.75' 12.0" x 92.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 189.50' S= 0.0136/' n=0.012 Cc= 0.900 .— 5- .... 4- H w 3 3 0 LL 2 n Pond 1R: 12" RCP FROM EX. DMH TO WETLAND Hydrograph Plot — Inflow — Primary 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall = 4.40" Prepared by Coler & Colantonio, Inc. Page 30 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Pond 3R: 10" RCP FROM EX. CB PARKING LOT TO EX. DMH Inflow = 0.57 cfs @ 12.11 hrs, Volume= 0.040 of Outflow = 0.56 cfs @ 12.11 hrs, Volume= 0.040 af, Atten= 0 %, Lag= 0.0 min Primary = 0.56 cfs @ 12.11 hrs, Volume= 0.040 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 2 Peak Elev= 191.05' Storage= 5 cf ` Plug -Flow detention time= 0.3 min calculated for 0.040 of (100% of inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -feet) (sq -ft) 190.60 0 0 0 0 190.65 12 0 0 12 194.65 12 48 48 61 197.35 7 25 74 91 198.10 0 2 75 99 ` 198.60 285 48 123 384 Qrimary OutFlow (Free Discharge) ` "11 =Culvert # Routing Invert Outlet Devices ` 1 Primary 190.65' 10.0" x 75.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 189.15' S= 0.0200 '/' n=0.012 Cc= 0.900 Pond 3R: 10" RCP FROM EX. CB PARKING LOT TO EX. DMH Hydrograph Plot 0 0.`. 0 0.4 0 w 0.2 v 3 0 0 LL O.i 0 0.1 0 O.0 6 5 5- 4- 5- 0 1 2 3 4 5 b 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) Inflow Primary O N v U 0 "' O v� U o -AR >%C)o c e o C Qo c�o`_2 a U 0 M cn Of U N d` A x U) c � N 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rain fall= 5.40" Prepared by Coler & Colantonio, Inc. Page 33 HydroCAD® 6.00 s/n 001012 @1986-2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 1S: AREA TRIB. NORTH & EAST PROJECT SITE Runoff = 6.65 cfs @ 12.27 hrs, Volume= 0.674 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 5.40" Area (sf) CN Description ` 5,384 98 Paved parking & drives 20,993 61 >75% Grass cover, Good, HSG B 7,620 58 Woods /grass comb., Good, HSG B 1,078 32 Woods /grass comb., Good, HSG A `— 1,788 85 Gravel roads, HSG B 285 98 Rock Outcrop 3,753 98 Paved roofs & driveways 38,882 90 Wetland, HSG A 64,594 30 Woods, Good, HSG A 143,464 55 Woods, Good, HSG B ` 9,057 78 Row crops, straight row, Good, HSG B 296,898 57 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) Mft) (ft/sec) (cfs) 9.1 70 0.0900 0.1 Sheet Flow, A -B Woods: Light underbrush n= 0.400 P2= 3.00" -- 0.9 75 0.0800 1.4 Shallow Concentrated Flow, B -C Woodland Kv= 5.0 fps 1.8 120 0.0500 1.1 Shallow Concentrated Flow, C -D ` Woodland Kv= 5.0 fps 1.5 85 0.0350 0.9 Shallow Concentrated Flow, D -E Woodland Kv= 5.0 fps 2.0 160 0.0700 1.3 Shallow Concentrated Flow, E -F — Woodland Kv= 5.0 fps 1.5 45 0.0100 0.5 Shallow Concentrated Flow, F -G Woodland Kv= 5.0 fps -- 16.8 555 Total 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall = 5.40" Prepared by Coler & Colantonio, Inc. Page 35 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 43/2003 Subcatchment 2S: AREA TRIB. TO PROJECT SITE SOUTH Runoff = 0.60 cfs @ 12.31 hrs, Volume= 0.081 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 5.40" Area (sf) CN Description .— 3,041 98 Paved road & drives 15,543 39 >75% Grass cover, Good, HSG A 10,857 61 >75% Grass cover, Good, HSG B 23,120 32 Woods /grass comb., Good, HSG A 4,498 58 Woods /grass comb., Good, HSG B 2,591 98 Paved roofs 3,149 30 Woods, Good, HSG A -- 8,624 55 Woods, Good, HSG B 71,423 47 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.0 75 0.0150 0.1 Sheet Flow, A -B Grass: Short n=0.150 P2=3.00" 4.7 200 0.0200 0.7 Shallow Concentrated Flow, B-C Woodland Kv= 5.0 fps 13.7 275 Total Subcatchment 2S: AREA TRIB. TO PROJECT SITE SOUTH Hydrograph Plot — Runoff H w V O LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall= 5.40" Prepared by Coler & Colantonio, Inc. Page 37 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 4S: MAIN BUILDING ROOF Runoff = 1.81 cfs @ 12.07 hrs, Volume= 0.140 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 5.40" Area (sf) CN Description 14,850 98 Paved roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Roof Subcatchment 4S: MAIN BUILDING ROOF Hydrograph Plot 2 3 1 0 0 1 s 4 5 b 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) �- Runoff 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall= 5.40" Prepared by Coler & Colantonio, Inc. Page 39 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 6S: AREA TRIB. TO NORTH EAST WETLAND AREA Runoff = 0.61 cfs @ 12.28 hrs, Volume= 0.089 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 5.40" Area (sf) CN Description 10,650 61 >75% Grass cover, Good, HSG B 464 98 Paved roofs 15,471 90 Wetland, HSG A 4,375 67 Row crops, straight row, Good, HSG A `— 62,860 30 Woods, Good, HSG A 93,820 45 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.4 50 0.0200 0.1 Sheet Flow, A -B Cultivated: Residue >20% n= 0.170 P2= 3.00" 2.8 140 0.0280 0.8 Shallow Concentrated Flow, B -C Woodland Kv= 5.0 fps 9.2 190 Total Subcatchment 6S: AREA TRIB. TO NORTH EAST WETLAND AREA Hydrograph Plot — Runoff w w 0 U. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall = 5.40" Prepared by Coler & Colantonio, Inc. Page 41 HydroCAD®6 00 s/n 001012 © 1986 -2001 Applied Microcomputer Syst 3/3/2003 Reach DP 1: DESIGN POINT #1 - 24" BOX CULVERT Inflow = 13.30 cfs @ 12.27 hrs, Volume= 1.493 of Outflow = 13.30 cfs @ 12.27 hrs, Volume= 1.493 af, Atten= 0 %, Lag= 0.0 milk Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Reach DP 1: DESIGN POINT #1 - 24" BOX CULVERT Hydrograph Plot 1 1 1 1 w 3 0 LL i. 3. I. 3. 3: T- 1 0 ,. Inflow — Outflow 0 1 2 3 4 5 6 7 6 9 W 11 1Z w Ig I 10 11 10 1v cJ Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall = 5.40" Prepared by Coler & Colantonio, Inc. Page 43 HydroCAD®6 00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Pond 1 R: 12" RCP FROM EX. DMH TO WETLAND " Inflow = 6.39 cfs @ 12.12 hrs, Volume= 0.739 of Outflow = 6.26 cfs @ 12.14 hrs, Volume= 0.739 af, Atten= 2 %, Lag= 1.1 min Primary = 6.26 cfs @ 12.14 hrs, Volume= 0.739 of ` Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 3 Peak Elev= 194.41' Storage= 43 cf `– Plug -Flow detention time= 0.3 min calculated for 0.737 of (100% of inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -feet) (sq -ft) 190.75 0 0 0 0 190.80 12 0 0 12 194.80 12 48 48 61 196.75 3 14 62 81 197.40 0 1 62 85 rimary OutFlow (Free Discharge) r-1 =Culvert ` # Routing Invert Outlet Devices 1 Primary 190.75' 12.0" x 92.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 189.50' S= 0.0136 'P n=0.012 Cc= 0.900 Pond 1 R: 12" RCP FROM EX. DMH TO WETLAND Hydrograph Plot If N w V O LL M Mi n — Inflow — Primary 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall= 5.40" Prepared by Coler & Colantonio, Inc. Page 45 HydroCAD ®6 00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Pond 3R: 10" RCP FROM EX. CB PARKING LOT TO EX. DMH `— Inflow = 0.77 cfs @ 12.11 hrs, Volume= 0.055 of Outflow = 0.77 cfs @ 12.11 hrs, Volume= 0.055 af, Atten= 0 %, Lag= 0.0 min Primary = 0.77 cfs @ 12.11 hrs, Volume= 0.055 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 2 Peak Elev= 191.13' Storage= 6 cf Plug -Flow detention time= 0.3 min calculated for 0.054 of (100% of inflow) Storage and wetted areas determined by Conic sections �- Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -feet) (sq -ft) 190.60 0 0 0 0 .— 190.65 12 0 0 12 194.65 12 48 48 61 197.35 7 25 74 91 198.10 0 2 75 99 198.60 285 48 123 384 Primary OutFlow (Free Discharge) 't--1 =Culvert # Routing Invert Outlet Devices 1 Primary 190.65' 10.0" x 75.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 189.15' S=0.0200? n=0.012 Cc= 0.900 Pond 3R: 10" RCP FROM EX. CB PARKING LOT TO EX. DMH Hydrograph Plot Inflow Primary w V 3 O LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) U) N (0 0' a co LO cn ,:I- co I 1< c o ct I �o U M U) 60 -155 ROCKRIDGE PREF Type Ill 24 -hr Rainfall= 7.30" Prepared by Coler & Colantonio, Inc. Page 48 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 1S: AREA TRIB. NORTH & EAST PROJECT SITE Runoff = 13.79 cfs @ 12.25 hrs, Volume= 1.300 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 7.30" Area (sf) CN Description �- 5,384 98 Paved parking & drives 20,993 61 >75% Grass cover, Good, HSG B 7,620 58 Woods /grass comb., Good, HSG B ` 1,078 32 Woods /grass comb., Good, HSG A 1,788 85 Gravel roads, HSG B 285 98 Rock Outcrop 3,753 98 Paved roofs & driveways 38,882 90 Wetland, HSG A 64,594 30 Woods, Good, HSG A 143,464 55 Woods, Good, HSG B 9,057 78 Row crops, straight row, Good, HSG B 296,898 57 Weighted Average Tc Length Slope Velocity Capacity Description ` (min) (feet) (ft/ft) (ft/sec) (cfs) 9.1 70 0.0900 0.1 Sheet Flow, A -B Woods: Light underbrush n= 0.400 P2= 3.00" 0.9 75 0.0800 1.4 Shallow Concentrated Flow, B -C Woodland Kv= 5.0 fps 1.8 120 0.0500 1.1 Shallow Concentrated Flow, C -D ` Woodland Kv= 5.0 fps 1.5 85 0.0350 0.9 Shallow Concentrated Flow, D -E Woodland Kv= 5.0 fps 2.0 160 0.0700 1.3 Shallow Concentrated Flow, E -F ` Woodland Kv= 5.0 fps 1.5 45 0.0100 0.5 Shallow Concentrated Flow, F -G Woodland Kv= 5.0 fps �- 16.8 555 Total 60 -155 ROCKRIDGE PREF Type /// 24 -hr Rainfall = 7.30" Prepared by Coler & Colantonio, Inc. Page 50 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Subcatchment 2S: AREA TRIB. TO PROJECT SITE SOUTH ` Runoff = 1.92 cfs @ 12.22 hrs, Volume= 0.190 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs �- Type III 24 -hr Rainfall= 7.30" (min) Area (sf) CN Description �. 3,041 98 Paved road & drives 15,543 39 >75% Grass cover, Good, HSG A 10,857 61 >75% Grass cover, Good, HSG B 23,120 32 Woods /grass comb., Good, HSG A 4,498 58 Woods /grass comb., Good, HSG B 2,591 98 Paved roofs 3,149 30 Woods, Good, HSG A — 8,624 55 Woods, Good, HSG B 71,423 47 Weighted Average ` Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 9.0 75 0.0150 0.1 Sheet Flow, A -B Grass: Short n=0.150 P2=3.00" ` 4.7 200 0.0200 0.7 Shallow Concentrated Flow, B -C Woodland Kv= 5.0 fps 13.7 275 Total Subcatchment 2S: AREA TRIB. TO PROJECT SITE SOUTH — Hydrograph Plot N w V — O 1 LL – Runoff 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall = 7.30" Prepared by Coler & Colantonio, Inc. ' Page 52 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems :3/3/2003 Subcatchment 4S: MAIN BUILDING ROOF Runoff = 2.46 cfs @ 12.07 hrs, Volume= 0.192 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 7.30" Area (sf) CN Description 14,850 98 Paved roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Roof Subcatchment 4S: MAIN BUILDING ROOF Hydrograph Plot 3 0 U. — Runoff 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall= 7.30" Prepared by Coler & Colantonio, Inc. Page 54 HydroCAD ®6 00 s/n 001012 @1986-2001 Applied Microcomputer Sys tems 3/3/2003 Subcatchment 6S: AREA TRIB. TO NORTH EAST WETLAND AREA Runoff = 2.41 cfs @ 12.16 hrs, Volume= 0.220 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 7.30" Area (sf) CN Description 10,650 61 >75% Grass cover, Good, HSG B 464 98 Paved roofs 15,471 90 Wetland, HSG A 4,375 67 Row crops, straight row, Good, HSG A ` 62,860 30 Woods Good HSG A 93,820 45 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) _ 6.4 50 0.0200 0.1 Sheet Flow, A -B _ Cultivated: Residue >20% n=0.170 P2=3.00" 2.8 140 0.0280 0.8 Shallow Concentrated Flow, B -C Woodland Kv= 5.0 fps 9.2 190 Total Subcatchment 6S: AREA TRIB. TO NORTH EAST WETLAND AREA Hydrograph Plot w 0 U. 1 -1 --Runoff lummmmomwA 0 1 2 3 4 5 6 7 5 9 to 11 lZ 1.5 w ID iv ii io 1 Z Time (hours) 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall = 7.30" Prepared by Coler & Colantonio, Inc. Page 56 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Reach DP 1: DESIGN POINT #1 - 24" BOX CULVERT Inflow = 22.65 cfs @ 12.25 hrs, Volume= 2.726 of Outflow = 22.65 cfs @ 12.25 hrs, Volume= 2.726 af, Atten= 0 %, Lag= 0.0 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Reach DP 1: DESIGN POINT #1 - 24" BOX CULVERT Hydrograph Plot N v 3 0 24- 22.65 cfs 22 20- 18- 16 14 12_ 10 8- 6 4 2 0 — Inflow — Outflow 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall= 7.30" Prepared by Coler & Colantonio, Inc. Page 58 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Pond 1R: 12" RCP FROM EX. DMH TO WETLAND v Inflow = 7.06 cfs @ 12.38 hrs, Volume= 1.237 of Outflow = 7.06 cfs @ 12.38 hrs, Volume= 1.236 af, Atten= 0 %, Lag= 0.2 min Primary = 7.06 cfs @ 12.38 hrs, Volume= 1.236 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 3 ` Peak Elev= 195.47' Storage= 53 cf Plug -Flow detention time= 0.2 min calculated for 1.236 of (100% of inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -feet) (sq -ft) 190.75 0 0 0 0 -- 190.80 12 0 0 12 194.80 12 48 48 61 196.75 3 14 62 81 ` 197.40 0 1 62 85 Primary OutFlow (Free Discharge) 't-1 =Culvert # Routing Invert Outlet Devices 1 Primary 190.75' 12.0" x 92.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 �- Outlet Invert= 189.50' S= 0.0136 'P n=0.012 Cc= 0.900 Pond 1R: 12" RCP FROM EX. DMH TO WETLAND ` Hydrograph Plot 7 ■ N w 3 O LL 91 91 ) I 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) Inflow Primary 60 -155 ROCKRIDGE PREF Type 111 24 -hr Rainfall= 7.30" Prepared by Coler & Colantonio, Inc. Page 60 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/3/2003 Pond 3R: 10" RCP FROM EX. CB PARKING LOT TO EX. DMH `- Inflow = 1.17 cfs @ 12.11 hrs, Volume= 0.084 of Outflow = 1.17 cfs @ 12.11 hrs, Volume= 0.084 af, Atten= 0 %, Lag= 0.0 min Primary = 1.17 cfs @ 12.11 hrs, Volume= 0.084 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 2 Peak Elev= 191.27' Storage= 8 cf Plug -Flow detention time= 0.3 min calculated for 0.084 of (100% of inflow) Storage and wetted areas determined by Conic sections �- Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -feet) (sq -ft) 190.60 0 0 0 0 190.65 12 0 0 12 194.65 12 48 48 61 197.35 7 25 74 91 198.10 `- 0 2 75 gg 198.60 285 48 123 384 ri mary OutFlow (Free Discharge) 1= Culvert # Routing Invert Outlet Devices 1 Primary 190.65' 10.0" x 75.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 189.15' S= 0.0200? n= 0.012 Cc= 0.900 Pond 3R: 10" RCP FROM EX. CB PARKING LOT TO EX. DMH Hydrograph Plot w V 3 O LL 0 � I O y 1u 11 12 13 14 15 16 17 18 19 20 Time (hours) — Inflow — Primary U) cli Q 5 ---- (N Cl) L 0 CN C11 m I V C'. C'. CN O, i c c x ,>, C w t" 77 C , w CN C') Lf) At C OC U) U) Cl) C4 Cl) U U) U) 0) co 60 -155 ROCKRIDGE POST F Type Ill 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 3 -- HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems /4/2003 Subcatchment 16S: AREA TRIG. TO AD #1 Tc =4.4 min CN =66 Area =4,760 sf Runoff= 0.06 cfs 0.004 of Subcatchment 17S: AREA TRIB. TO CB#4 Subcatchment 18S: AREA TRIB. TO CB #6 Tc =5.0 min CN =95 Area =3,802 sf Runoff= 0.24 cfs 0.017 of Tc =5.0 min CN =90 Area =1,823 sf Runoff= 0.10 cfs 0.007 of Subcatchment 19S: AREA TRIB. TO CB #7 Tc =5.0 min CN =88 Area =6,180 sf Runoff= 0.30 cfs 0.020 of Subcatchment 20S: AREA TRIB. TO DCB #1 Tc =5.0 min CN =87 Area =5,767 sf Runoff= 0.27 cfs 0.018 of Subcatchment 21S: AREA TRIB TO AD #2 & AD #3 Tc =4.6 min CN =63 Area =3,010 sf Runoff= 0.02 cfs 0.002 of Subcatchment 22S: COTTAGES (3/4 TRIB. AREA) Tc =5.0 min CN =98 Area = 13,991 sf Runoff= 0.94 cfs 0.071 of Subcatchment 23S: COTTAGES (1/4 TRIB. AREA) Tc =5.0 min CN =98 Area =4,664 sf Runoff= 0.31 cfs 0.024 of Subcatchment 24S: AREA TRIB. TO AD#4,5,6 (COURTYARD) Tc =5.0 min CN =81 Area =5,547 sf Runoff= 0.19 cfs 0.013 of Subcatchment 25S: AREA TRIB. TO CB #3 Subcatchment 26S: AREA TRIB. TO CB #2 Tc =5.0 min CN =82 Area =910 sf Runoff= 0.03 cfs 0.002 of Tc =5.0 min CN =72 Area =7,720 sf Runoff= 0.15 cfs 0.011 of Reach 1R: 12" RCP FROM EX. DMH TO OUTLET Inflow= 0.96 cfs 0.075 of Length = 94.0' Max Vel= 4.1 fps Capacity= 3.89 cfs Outflow= 0.95 cfs 0.075 of Reach 2R: 12" CI FROM EX. ROOF DRAINS TO EX. DMH Inflow= 1.00 cfs 0.075 of Length= 170.0' Max Vel= 3.7 fps Capacity= 3.31 cfs Outflow= 0.96 cfs 0.075 of Reach 3R: 15" HDPE FROM CB #14 TO CB #12 Inflow= 1.09 cfs 0.097 of Length= 100.0' Max Vel= 3.6 fps Capacity= 5.86 cfs Outflow= 1.07 cfs 0.096 of Reach 5R: DRAIN PIPE KING STREET TO DP #1 Inflow= 0.01 cfs ,0.004 of Length= 290.0' Max Vel= 1.3 fps Capacity= 5.32 cfs Outflow= 0.01 cfs 0.004 of Reach 6R: 12" HDPE FROM CB #11 TO DMH #1 Inflow= 0.63 cfs ,0.046 of Length= 66.0' Max Vel= 3.6 fps Capacity= 3.86 cfs Outflow= 0.62 cfs 0.046 of 60 -155 ROCKRIDGE POST F Type /// 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 5 HydroCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 8/4/2003 Reach 26R: 12" HDPE FROM CB #6 TO DMH#4 Inflow= 0.10 cfs 0.007 of Length= 10.0' Max Vel= 2.1 fps Capacity= 3.86 cfs Outflow= 0.10 cfs 0.007 of Reach 28R: 12" HDPE FROM CB #7 TO DMH #5 Inflow= 0.30 cfs 0.020 of Length= 49.0' Max Vel= 3.3 fps Capacity= 4.71 cfs Outflow= 0.30 cfs'0.020 of Reach 33R: 10" PVC ROOF DRAIN MANIFOLD Inflow= 0.91 cfs 0.066 of Length= 100.0' Max Vel= 5.0 fps Capacity= 3.17 cfs Outflow= 0.89 cfs 1 0.066 of Reach DP 10: DESIGN POINT #1 - 24" BOX CULVERT Inflow= 1.90 cfs 0.403 of Outflow= 1.90 cfs 0.403 of -- Reach DP 20: DESIGN POINT #2 - 30" RCP CULVERT Inflow= 0.01 cfs 0.003 of Outflow= 0.01 cfs 0.003 of Pond 1 P: UNDERGROUND DETENTION SYSTEM Peak Storage= 7,974 cf Inflow= 5.92 cfs 0.566 of Discarded= 0.35 cfs 0.308 of Primary= 1.24 cfs 0.245 of Secondary= 0.00 cfs 0.000 of Outflow= 1.59 cfs 0.553 of Reach 29R: 12" HDPE FROM CB#8 TO DMH #5 Inflow= 0.14 cfs 0.019 of Length= 12.0' Max Vel= 2.3 fps Capacity= 3.86 cfs Outflow= 0.14 cfs 0.019 of Reach 30R: 12" HDPE FROM DCB #1 TO DMH #6 Inflow= 0.31 cfs 0.053 of Length= 20.0' Max Vel= 3.0 fps Capacity= 3.86 cfs Outflow= 0.31 cfs 0.053 of Reach 31 R: 10" HDPE ROOF MANIFOLD Inflow= 0.31 cfs 0.024 of Length= 100.0' Max Vel= 3.0 fps Capacity= 2.37 cfs Outflow= 0.30 cfs 0.024 of Reach 32R: 10" HDPE ROOF MANIFOLD Inflow= 0.94 cfs 0.071 of Length= 200.0' Max Vel= 4.1 fps Capacity= 2.37 cfs Outflow= 0.90 cfs 0.071 of Pond 4R: 12" HDPE FROM CB#9 TO UNDERGROUND DETEIf'd01 ds;FJDA 18 cf Inflow= 0.59 cfs 0.041 of Primary= 0.58 cfs 0.040 of Outflow= 0.58 cfs 0.040 of Pond 11 R: 18" FROM DMH #8 TO DMH#9 Peak Storage= 9 cf Inflow= 2.39 cfs 0.229 of Primary= 2.39 cfs 0.229 of Outflow= 2.39 cfs 0.229 of Pond 12R: 18" HDPE FROM DMH #9 TO DMH #10 Peak Storage= 9 cf Inflow= 2.41 cfs 0.231 of Primary= 2.41 cfs 0.231 of Outflow= 2.41 cfs 0.231 of Pond 27R: 24" CMP FROM UNDERGROUND DETENTION TCPWFage= 10 cf Inflow= 1.05 cfs 0.135 of Primary= 1.05 cfs 0.134 of Outflow= 1.05 cfs 0.134 of Pond 35R: 24" CMP FROM DMH #10 TO UNDERGROUND DE1Wd4TISbtAQ €Acf Inflow= 3.18 cfs 0.302 of Primary= 3.18 cfs 0.301 of Outflow= 3.18 cfs 0.301 of Runoff Area = 14.938 ac Volume = 0.728 of Average Depth = 0.58" 60 -155 ROCKRIDGE POST — F Type /// 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 7 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 1S: AREA TRIB. TO MAIN WETLAND AREA Hydrograph Plot unoff N w V O LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST_F Type 111 24 -hr Rainfall = 3.00" Prepared by Coler & Colantonio, Inc. 1 1 Page 9 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems g/4/2003 Subcatchment 3S: AREA TRIB. PROJECT SITE WEST Runoff = 1.09 cfs @ 12.22 hrs, Volume= 0.097 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 21,785 98 Paved parking & drives 21,740 61 >75% Grass cover, Good, HSG B 437 98 Paved roofs 43,962 80 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) -- 14.6 70 0.0100 0.1 Sheet Flow, A -B Grass: Dense n= 0.240 P2= 3.00" 0.3 35 0.0100 2.0 Shallow Concentrated Flow, B -C Paved Kv= 20.3 fps ` 0.3 75 0.0160 4.7 2.57 Circular Channel (pipe), C -D Diam= 10.0" Area= 0.5 sf Perim= 2.6' r= 0.21' n= 0.01 15.2 180 Total Subcatchment 3S: AREA TRIB. PROJECT SITE WEST ` Hydrograph Plot S 0 LL — Runoff 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Wage 11 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 5S: AREA TRIB. TO CB#9, 10 (EAST PARKING) Runoff = 0.59 cfs @ 12.07 hrs, Volume= 0.041 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall = 3.00" Area (sf) CN Description 8,190 98 Paved parking 1,370 69 50 -75% Grass cover, Fair, HSG B 9,560 94 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Parking Lot Subcatchment 5S: AREA TRIB. TO CB#9, 10 (EAST PARKING) _ Hydrograph Plot — Runoff 0 LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall = 3.00" Prepared by Coler & Colantonio, Inc. Page 13 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4112003 Subcatchment 7S: PROP. 3 -STORY BUILDING Runoff = 0.71 cfs @ 12.07 hrs, Volume= 0.054 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 10,615 98 Paved roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Roof Subcatchment 7S: PROP. 3 -STORY BUILDING Hydrograph Plot - N w V 3 O LL U 1 c .3 4 D 0 / 6 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 15 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 9S: AREA TRIB. TO CB #1 Runoff = 0.18 cfs @ 12.18 hrs, Volume= 0.018 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 9.9 270 Total Subcatchment 9S: AREA TRIB. TO CB#1 Hydrograph Plot --Runoff a w u 3 0 LL U i z s 4 5 ti / 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 2,586 98 Paved driveway 6,323 69 50 -75% Grass cover, Fair, HSG B 11,924 55 Woods, Good, HSG B 20,833 65 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.9 70 0.0950 0.1 Sheet Flow, A -B Woods: Light underbrush n= 0.400 P2= 3.00" 0.2 20 0.0700 1.9 Shallow Concentrated Flow, B -C Short Grass Pasture Kv= 7.0 fps 0.8 180 0.0320 3.6 Shallow Concentrated Flow, C -D Paved Kv= 20.3 fps 9.9 270 Total Subcatchment 9S: AREA TRIB. TO CB#1 Hydrograph Plot --Runoff a w u 3 0 LL U i z s 4 5 ti / 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type /// 24 -hr Rainfa9= 3.00" Prepared by Coler & Colantonio, Inc. Page 17 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 11 S: AREA TRIB. TO CB #8 Runoff = 0.14 cfs @ 12.28 hrs, Volume= 0.019 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 2,185 69 50 -75% Grass cover, Fair, HSG B 3,556 98 Paved driveways 26,384 55 Woods, Good, HSG B 32,125 61 Weighted Average Tc Length Slope Velocity Capacity Description in) (feet) (ft/ft) (ft/sec) (cfs) 10.7 80 0.0800 0.1 Sheet Flow, A -B Woods: Light underbrush n= 0.400 P2= 3.00" 1.1 95 0.0800 1.4 Shallow Concentrated Flow, B-C Woodland Kv= 5.0 fps 0.1 20 0.1500 2.7 Shallow Concentrated Flow, C -D Short Grass Pasture Kv= 7.0 fps 0.4 105 0.0380 4.0 Shallow Concentrated Flow, D -E Paved Kv= 20.3 fps 12.3 300 Total Subcatchment 11S: AREA TRIB. TO CB#8 Hydrograph Plot — Runoff MMMMMMMMM a 3 0 LL U 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall=3. 00 " Prepared by Coler & Colantonio, Inc. Page 19 H droCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 13S: AREA TRIB. TO CB #12 Runoff = 0.27 cfs @ 12.07 hrs, Volume= 0.020 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall =3.00" Area (sf) CN Description 3,960 98 Paved parking & walks Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 13S: AREA TRIB. TO CB #12 Hydrograph Plot — Runoff w v 3 0 U . a o r a U 1u 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 21 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/41/2003 Subcatchment 15S: AREA TRIB. TO CB #14 Runoff = 0.27 cfs @ 12.08 hrs, Volume= 0.018 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 3,933 98 Paved driveways 1,545 61 >75% Grass cover, Good, HSG B 5,478 88 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 15S: AREA TRIB. TO CB#14 Hydrograph Plot — Runoff v 3 0 'a U 1 z s 4 5 ti 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall =3.00" Prepared by Coler & Colantonio, Inc. Page 23 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 17S: AREA TRIB. TO CB#4 Runoff = 0.24 cfs @ 12.07 hrs, Volume= 0.017 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 270 61 >75% Grass cover, Good, HSG B 3,532 98 Paved driveway & parking 3,802 95 Weighted Average Tc Length Slope Velocity Ca min) (feet) (ft/ft) (ft/sec) 5.0 Description Direct Entry, Impervious Subcatchment 17S: AREA TRIB. TO CB#4 Hydrograph Plot — Runoff a w v 3 0 LL U 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall =3.00" Prepared by Coler & Colantonio, Inc. Page 25 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 19S: AREA TRIB. TO CB #7 Runoff = 0.30 cfs @ 12.08 hrs, Volume= 0.020 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 4,570 98 Paved driveways & parking 1,610 61 >75% Grass cover, Good, HSG B 6,180 88 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 19S: AREA TRIB. TO CB#7 Hydrograph Plot — Runoff UMMMMMMMM a w v 3 0 LL u 1 z 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST_F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. page 27 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 21S: AREA TRIB TO AM & AD #3 Runoff = 0.02 cfs @ 12.11 hrs, Volume= 0.002 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area _(sf) CN Description 2,810 61 >75% Grass cover, Good, HSG B 200 98 Paved patio 3,010 63 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.3 30 0.0400 0.1 Sheet Flow, A -B Grass: Dense n= 0.240 P2= 3.00" 0.3 30. 0.0800 2.0 Shallow Concentrated Flow, B -C Short Grass P asture Kv= 7.0 fps 4.6 60 Total Subcatchment 21 S: AREA TRIB TO AM & AD #3 Hydrograph Plot --Runoff a w u 3 0 LL i z 3 4 b ti 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. page 29 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 23S: COTTAGES (1/4 TRIB. AREA) Runoff = 0.31 cfs @ 12.07 hrs, Volume= 0.024 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 4,664 98 Paved roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 23S: COTTAGES (1/4 TRIB. AREA) Hydrograph Plot — Runoff UMMMMMMMM a w v 3 0 LL i z s 4 5 ti 1 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST_F Type 111 24 -hr Rainfal1t Prepared by Coler & Colantonio, Inc. Page 31 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 25S: AREA TRIB. TO CB #3 Runoff = 0.03 cfs @ 12.08 hrs, Volume= 0.002 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 3.00" Area (sf) CN Description 525 98 Paved driveways & walks 385 61 >75% Grass cover Good HSG B 910 82 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 25S: AREA TRIB. TO CB#3 Hydrograph Plot — Runoff w v 3 0 'a v i o to iu 11 1z 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfa11:;3.00" Prepared by Coler & Colantonio, Inc. Page 33 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 1 R: 12" RCP FROM EX. DMH TO OUTLET Inflow = 0.96 cfs @ 12.10 hrs, Volume= 0.075 of Outflow = 0.95 cfs @ 12.11 hrs, Volume= 0.075 af, Atten= 2 %, Lag= 0.6 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.1 fps, Min. Travel Time= 0.4 min Avg. Velocity = 1.4 fps, Avg. Travel Time= 1.1 min Peak Depth= 0.34' Capacity at bank full= 3.89 cfs Inlet Invert= 190.80', Outlet Invert= 189.50' 12.0" Diameter Pipe n=0.014 Length= 94.0' Slope= 0.0138 '/' Reach 1 R: 12" RCP FROM EX. DMH TO OUTLET Hydrograph Plot IA a w v 3 0 LL Inflow — Outflow 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST _F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 35 HydroCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 3R: 15" HDPE FROM CB #14 TO CB #12 Inflow = 1.09 cfs @ 12.22 hrs, Volume= 0.097 of Outflow = 1.07 cfs @ 12.23 hrs, Volume= 0.096 af, Atten= 1 %, Lag= 0.9 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.6 fps, Min. Travel Time= 0.5 min Avg. Velocity = 1.6 fps, Avg. Travel Time= 1.0 min Peak Depth= 0.37' Capacity at bank full= 5.86 cfs Inlet Invert= 196.80', Outlet Invert= 196.10' 15.0" Diameter Pipe n=0.012 Length= 100.0' Slope= 0.0070 '/' Reach 3R: 15" HDPE FROM CB#14 TO CB#12 Hydrograph Plot 1.07 cfs 01 — 3 0 U. )- n 1 1) o .- .. is is 14 10 16 17 18 19 20 Time (hours) — Inflow — QUM Ow 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfoll= 3.00" Prepared by Coler & Colantonio, Inc. Page 37 ydroCADO 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3 /4/2003 Reach 6R: 12" HDPE FROM CB #11 TO DMH #1 Inflow = 0.63 cfs @ 12.12 hrs, Volume= 0.046 of Outflow = 0.62 cfs @ 12.13 hrs, Volume= 0.046 af, Atten= 2 %, Lag= 0.7 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.6 fps, Min. Travel Time= 0.3 min Avg. Velocity = 1.5 fps, Avg. Travel Time= 0.8 min Peak Depth= 0.27' Capacity at bank full= 3.86 cfs Inlet Invert= 198.13', Outlet Invert= 197.47' 12.0" Diameter Pipe n=0.012 Length= 66.0' Slope= 0.0100 '/' Reach 6R: 12" HDPE FROM CB #11 TO DMH #1 Hydrograph Plot Inflow - Outflow 3 0 LL U i c a 4 0 o / t$ 9 W 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 39 HydroCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 8R: 12" HDPE FROM CB#2 TO DMH #1 Inflow = 0.15 cfs @ 12.09 hrs, Volume= 0.011 of Outflow = 0.15 cfs @ 12.10 hrs, Volume= 0.011 af, Atten= 0 %, Lag= 0.3 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.1 fps, Min. Travel Time= 0.2 min Avg. Velocity = 1.4 fps, Avg. Travel Time= 0.3 min Peak Depth= 0.11' Capacity at bank full= 5.51 cfs Inlet Invert= 200.00', Outlet Invert= 199.43' 12.0" Diameter Pipe n=0.012 Length= 28.0' Slope= 0.0204 '/' Reach 8R: 12" HDPE FROM CB#2 TO DMH #1 Hydrograph Plot Inflow Outflow w 3 0 LL U I c a 4 a o i t$ U 1U 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST_F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 41 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 10R: 18" HDPE FROM DMH #7 TO DMH #8 Inflow = 2.24 cfs @ 12.17 hrs, Volume= 0.213 of Outflow = 2.22 cfs @ 12.18 hrs, Volume= 0.213 af, Atten= 1 %, Lag= 0.6 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 5.0 fps, Min. Travel Time= 0.4 min Avg. Velocity = 1.6 fps, Avg. Travel Time= 1.1 min Peak Depth= 0.45' Capacity at bank full= 11.38 cfs Inlet Invert= 195.67', Outlet Invert= 194.60' 18.0" Diameter Pipe n=0.012 Length= 107.0' Slope= 0.0100 '/' Reach 10R: 18" HDPE FROM DMH #7 TO DMH #8 Hydrograph Plot w v 3 0 LL al 0 4 a o i 6 a 1u 11 1z 13 14 15 16 17 18 19 20 Time (hours) Inflow - outflow 60 -155 ROCKRIDGE POST — F Type /// 24 -hr Rainfell= 3.00" Prepared by Coler & Colantonio, Inc. Page 43 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 14R: 12" HDPE FROM CB #13 TO DMH #8 Inflow = 0.23 cfs @ 12.07 hrs, Volume= 0.016 of Outflow = 0.22 cfs @ 12.09 hrs, Volume= 0.016 af, Atten= 2 %, Lag= 0.9 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 2.7 fps, Min. Travel Time= 0.4 min Avg. Velocity = 0.9 fps, Avg. Travel Time= 1.2 min Peak Depth= 0.16' Capacity at bank full= 3.86 cfs Inlet Invert= 198.47', Outlet Invert= 197.81' 12.0" Diameter Pipe n=0.012 Length= 66.0' Slope= 0.0100 '/' Reach 14R: 12" HDPE FROM CB#13 TO DMH#8 Hydrograp.h Plot Inflow utflow w 3 0 LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type /// 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 45 HydroCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 16R: 8" HDPE FROM YD #2 &3 TO DMH #9 Inflow = 0.02 cfs @ 12.11 hrs, Volume= 0.002 of Outflow = 0.02 cfs @ 12.11 hrs, Volume= 0.002 af, Atten= 1 %, Lag= 0.3 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 1.4 fps, Min. Travel Time= 0.2 min Avg. Velocity = 0.7 fps, Avg. Travel Time= 0.4 min Peak Depth= 0.06' Capacity at bank full= 1.31 cfs Inlet Invert= 200.00', Outlet Invert= 199.82' 8.0" Diameter Pipe n=0.012 Length= 18.0' Slope= 0.0100 '/' Reach 16R: 8" HDPE FROM YD#2 &3 TO DMH#9 Hydrograph Plot Inflow outFlow 3 0 LL v i z 3 4 5 b / is 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST - F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 47 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 18R: 12" HDPE FROM CB #3 TO DMH #2 Inflow = 0.03 cfs @ 12.08 hrs, Volume= 0.002 of Outflow = 0.03 cfs @ 12.08 hrs, Volume= 0.002 af, Atten= 0 %, Lag= 0.2 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 1.5 fps, Min. Travel Time= 0.1 min Avg. Velocity = 0.6 fps, Avg. Travel Time= 0.3 min Peak Depth= 0.07' Capacity at bank full= 3.86 cfs Inlet Invert= 205.67', Outlet Invert= 205.57' 12.0" Diameter Pipe n=0.012 Length= 10.0' Slope= 0.0100 '/' Reach 18R: 12" HDPE FROM CB#3 TO DMH #2 Hydrograph Plot Inflow OUM Ow 3 0 LL U i c a 4 0 0 f t$ 9 1U 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type /// 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 49 HydroCADO 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 20R: 15" HDPE FROM DMH #3 TO DMH#4 Inflow = 0.36 cfs @ 12.11 hrs, Volume= 0.035 of Outflow = 0.35 cfs @ 12.12 hrs, Volume= 0.035 af, Atten= 1 %, Lag= 0.4 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.6 fps, Min. Travel Time= 0.3 min Avg. Velocity = 1.8 fps, Avg. Travel Time= 0.7 min Peak Depth= 0.14' Capacity at bank full= 13.09 cfs Inlet Invert= 200.57', Outlet Invert= 198.05' 15.0" Diameter Pipe n=0.012 Length= 72.0' Slope= 0.0350 '/' Reach 20R: 15" HDPE FROM DMH #3 TO DMH#4 Hydrograph Plot Inflow — oUtFlow w v 3 0 LL i c s 4 5 U / tS 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type /// 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. I Page 51 HydroCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 22R: 18" HDPE FROM DMH #5 TO DMH #6 Inflow = 0.78 cfs @ 12.12 hrs, Volume= 0.081 of Outflow = 0.78 cfs @ 12.12 hrs, Volume= 0.081 af, Atten= 1%, Lag= 0.3 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.7 fps, Min. Travel Time= 0.2 min Avg. Velocity = 1.4 fps, Avg. Travel Time= 0.6 min Peak Depth= 0.27' Capacity at bank full= 11.50 cfs Inlet Invert= 195.10', Outlet Invert= 194.60' 18.0" Diameter Pipe n=0.012 Length= 49.0' Slope= 0.0102 '/' Reach 22R: 18" HDPE FROM DMH #5 TO DMH #6 Hydrograph Plot I Inflow — Outflow ,y 3 0 LL U i c a 4 5 b 1 t$ 9 1t) 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST _F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 53 HydroCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 25R: 12" HDPE FROM CB #5 TO DMH #3 Inflow = 0.14 cfs @ 12.21 hrs, Volume= 0.016 of Outflow = 0.14 cfs @ 12.21 hrs, Volume= 0.016 af, Atten= 0 %, Lag= 0.1 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 2.3 fps, Min. Travel Time= 0.1 min Avg. Velocity = 1.3 fps, Avg. Travel Time= 0.1 min Peak Depth= 0.13' Capacity at bank full= 3.86 cfs Inlet Invert= 202.02', Outlet Invert= 201.92' 12.0" Diameter Pipe n=0.012 Length= 10.0' Slope= 0.0100 '/' Reach 25R: 12" HDPE FROM CB #5 TO DMH #3 Hvdroaranh Pint Inflow - outflow w V 3 O LL I o CP lu ii 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 55 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 28R: 12" HDPE FROM CB #7 TO DMH #5 Inflow = 0.30 cfs @ 12.08 hrs, Volume= 0.020 of Outflow = 0.30 cfs @ 12.08 hrs, Volume= 0.020 af, Atten= 1 %, Lag= 0.5 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.3 fps, Min. Travel Time= 0.2 min Avg. Velocity = 1.2 fps, Avg. Travel Time= 0.7 min Peak Depth= 0.17' Capacity at bank full= 4.71 cfs Inlet Invert= 197.23', Outlet Invert= 196.50' 12.0" Diameter Pipe n=0.012 Length= 49.0' Slope= 0.0149 '/' Reach 28R: 12" HDPE FROM CB#7 TO DMH #5 Hydrograph Plot Inflow Outflow U I 1 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) N w V 3 O LL U I 1 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 57 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 30R: 12" HDPE FROM DCB#1 TO DMH #6 Inflow = 0.31 cfs @ 12.36 hrs, Volume= 0.053 of Outflow = 0.31 cfs @ 12.37 hrs, Volume= 0.053 af, Atten= 0 %, Lag= 0.2 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.0 fps, Min. Travel Time= 0.1 min Avg. Velocity = 1.5 fps, Avg. Travel Time= 0.2 min Peak Depth= 0.19' Capacity at bank full= 3.86 cfs Inlet Invert= 194.50', Outlet Invert= 194.30' 12.0" Diameter Pipe n=0.012 Length= 20.0' Slope= 0.0100 '/' Reach 30R: 12" HDPE FROM DCB#1 TO DMH #6 Hydrograph Plot Inflow — Outflow N w V 3 O LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rai4all= 3.00" Prepared by Coler & Colantonio, Inc. Page 59 HydroCADO 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 32R: 10" HDPE ROOF MANIFOLD Inflow = 0.94 cfs @ 12.07 hrs, Volume= 0.071 of Outflow = 0.90 cfs @ 12.10 hrs, Volume= 0.071 af, Atten= 4 %, Lag= 1.6 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.1 fps, Min. Travel Time= 0.8 min Avg. Velocity = 1.4 fps, Avg. Travel Time= 2.3 min Peak Depth= 0.36' Capacity at bank full= 2.37 cfs Inlet Invert= 197.50', Outlet Invert= 195.50' 10.0" Diameter Pipe n=0.012 Length= 200.0' Slope= 0.0100 '/' Reach 32R: 10" HDPE ROOF MANIFOLD Hydrograph Plot ` N w V 3 O LL Inflow Outflow 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 61 HydroCADO 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach DP 10: DESIGN POINT #1 - 24" BOX CULVERT Inflow = 1.90 cfs @ 12.43 hrs, Volume= 0.403 of Outflow = 1.90 cfs @ 12.43 hrs, Volume= 0.403 af, Atten= 0 %, Lag= 0.0 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Reach DP 10: DESIGN POINT #1 - 24" BOX CULVERT Hydrograph Plot 2 1.90 cfs N V 3 1 O LL 0, Inflow Outflow 1 1 j 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 63 HydroCADO 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 9 Peak Elev= 192.58' Storage= 7,974 cf Plug -Flow detention time= 71.1 min calculated for 0.552 of (97% of inflow) Storage and wetted areas determined by Irregular sections Elevation Pond 1P: UNDERGROUND DETENTION SYSTEM Inflow = 5.92 cfs @ 12.11 hrs, Volume= 0.566 of Outflow = 1.59 cfs @ 12.64 hrs, Volume= 0.553 af, Atten= 73 %, Lag= 32.1 min Discarded = 0.35 cfs @ 11.25 hrs, Volume= 0.308 of ` Primary = 1.24 cfs @ 12.64 hrs, Volume= 0.245 of Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 9 Peak Elev= 192.58' Storage= 7,974 cf Plug -Flow detention time= 71.1 min calculated for 0.552 of (97% of inflow) Storage and wetted areas determined by Irregular sections Elevation Surf.Area Perim. Open Inc.Store Cum.Store Wet.Area ` (feet) (sq -ft) (feet) ( %) (cubic -feet) (cubic -feet) (sq -ft) 190.50 7,000 610.0 30.0 0 0 7,000 191.00 7,000 610.0 30.0 1,050 1,050 7,305 191.50 7,000 610.0 55.0 1,925 2,975 7,610 192.00 7,000 610.0 64.0 2,240 5,215 7,915 192.50 7,000 610.0 68.0 2,380 7,595 8,220 ` 193.00 7,000 610.0 71.0 2,485 10,080 8,525 193.50 7,000 610.0 72.0 2,520 12,600 8,830 194.00 7,000 610.0 71.0 2,485 15,085 9,135 194.50 7,000 610.0 68.0 2,380 17,465 9,440 ` 195.00 7,000 610.0 64.0 2,240 19,705 9,745 195.50 7,000 610.0 55.0 1,925 21,630 10,050 195.90 7,000 610.0 30.0 840 22,470 10,294 196.00 7,000 610.0 30.0 210 22,680 10,355 Qiscarded OutFlow (Free Discharge) 1= Exfiltration Primary OutFlow (Free Discharge) 2=Orifice/Grate 3= Orifice /Grate = Orifice /Grate -5 econdary OutFlow (Free Discharge) = Orifice /Grate # Routing Invert Outlet Devices ` 1 Discarded 0.00' 0.003000 fpm Exfiltration over entire Surface area 2 Primary 191.20' 6.0" Vert. Orifice /Grate C= 0.600 3 Primary 193.00' 10.0" Vert. Orifice /Grate C= 0.600 4 Primary 192.00' 0.17'x 3.00' Vert. Orifice /Grate C= 0.600 5 Secondary 195.00' 30.0" Horiz. Orifice /Grate Limited to weir flow C= 0.600 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall = 3.00" Prepared by Coler & Colantonio, Inc. Page 65 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Pond 4R: 12" HDPE FROM CB#9 TO UNDERGROUND DETENTION AREA Inflow = 0.59 cfs @ 12.07 hrs, Volume= 0.041 of Outflow = 0.58 cfs @ 12.07 hrs, Volume= 0.040 af, Atten= 0 %, Lag= 0.1 min ,._ Primary = 0.58 cfs @ 12.07 hrs, Volume= 0.040 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs '- Peak Elev= 194.23' Storage= 18 cf Plug -Flow detention time= 6.2 min calculated for 0.040 of (99% of inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -feet) (sq -ft) ` 192.75 0 0 0 0 192.76 12 0 0 12 193.00 12 3 3 15 194.00 12 12 15 27 — 195.00 12 12 27 40 196.00 12 12 39 52 -- Primary OutFlow (Free Discharge) 't--1 =Culvert # Routing Invert Outlet Devices 1 Primary 193.76' 12.0" x 120.0' long Culvert CMP, square edge headwall, Ke= 0.500 Outlet Invert= 192.17' S=0.0132'/' n=0.024 Cc= 0.900 Pond 4R: 12" HDPE FROM CB#9 TO UNDERGROUND DETENTION AREA Hydrograph Plot 0 0 0 N 0 3 O LL 0 -- 0 —inflow — Primary 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall= 3.00" Prepared by Coler & Colantonio, Inc. Page 67 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Pond 12R: 18" HDPE FROM DMH#9 TO DMH #10 Inflow = 2.41 cfs @ 12.16 hrs, Volume= 0.231 of Outflow = 2.41 cfs @ 12.17 hrs, Volume= 0.231 af, Atten= 0 %, Lag= 0.0 min Primary = 2.41 cfs @ 12.17 hrs, Volume= 0.231 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 5 `– Peak Elev= 194.30' Storage= 9 cf Plug -Flow detention time= 0.2 min calculated for 0.230 of (100% of inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -feet) (sq -ft) 193.51 0 0 0 0 193.52 12 0 0 12 194.00 12 6 6 18 195.00 12 12 18 30 196.00 12 12 30 42 197.00 12 12 42 55 Primary OutFlow (Free Discharge) 't-1 =Culvert # Routing Invert Outlet Devices 1 Primary 193.57' 18.0" x 50.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 193.07' S=0.0100'/' n=0.012 Cc= 0.900 Pond 12R: 18" HDPE FROM DMH#9 TO DMH #10 Hydrograph Plot N w V 3 O LL — Inflow — Primary 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall = 3.00" Prepared by Coler & Colantonio, Inc. Page 69 HydroCAD® 6.00 s/n 001012 01986 -2001 Applied Microcomputer Systems 3/4/2003 Pond 35R: 24" CMP FROM DMH #10 TO UNDERGROUND DETENTION AREA Inflow = 3.18 cfs @ 12.13 hrs, Volume= 0.302 of Outflow = 3.18 cfs @ 12.13 hrs, Volume= 0.301 af, Atten= 0 %, Lag= 0.1 min _ Primary = 3.18 cfs @ 12.13 hrs, Volume= 0.301 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 5 ` Peak Elev= 193.98' Storage= 3 cf Plug -Flow detention time= 0.0 min calculated for 0.301 of (100% of inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum.Store Wet.Area (feet) (sq -ft) (cubic -feet) (cubic -feet) (sq -ft) ` 193.69 0 0 0 0 193.70 12 0 0 12 194.00 12 4 4 16 195.00 12 12 16 28 ` 196.00 12 12 28 40 Primary OutFlow (Free Discharge) 't-1 =Culvert # Routing Invert Outlet Devices 1 Primary 193.04' 24.0" x 34.0' long Culvert CMP, square edge headwall, Ke= 0.500 Outlet Invert= 192.70' S=0.0100'/' n=0.024 Cc= 0.900 Pond 35R: 24" CMP FROM DMH #10 TO UNDERGROUND DETENTION AREA Hydrograph Plot 3 -1 v 3 0 LL 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) —Inflow — Primary 0 u L V Y : c � .Q O o_ Q N M •� 0 Ln C N e� N c6 O 0 00 CN CN o L E ? N NL 0 o C L _ � O - N C CO Q ^ N O C4 Q N N QI— N M M I 0 t n N V CO 0) I 7 N 00 rn 00 60 -155 ROCKRIDGE POST F Type /// 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 72 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 16S: AREA TRIB. TO AD #1 Tc =4.4 min CN =66 Area =4,760 sf Runoff= 0.16 cfs 0.011 of Subcatchment 17S: AREA TRIB. TO CB#4 Subcatchment 18S: AREA TRIB. TO CB #6 Subcatchment 19S: AREA TRIB. TO CB #7 Subcatchment 20S: AREA TRIB. TO DCB #1 Tc =5.0 min CN =95 Area =3,802 sf Runoff= 0.36 cfs 0.026 of Tc =5.0 min CN =90 Area =1,823 sf Runoff= 0.16 cfs 0.011 of Tc =5.0 min CN =88 Area =6,180 sf Runoff= 0.51 cfs 0.035 of Tc =5.0 min CN =87 Area =5,767 sf Runoff= 0.46 cfs 0.031 of Subcatchment 21 S: AREA TRIB TO AD #2 & AD#3 Tc =4.6 min CN =63 Area =3,010 sf Runoff= 0.08 cfs 0.006 of Subcatchment 22S: COTTAGES (3/4 TRIB. AREA) Tc =5.0 min CN =98 Area = 13,991 sf Runoff= 1.39 cfs 0.106 of Subcatchment 23S: COTTAGES (1/4 TRIB. AREA) Tc =5.0 min CN =98 Area =4,664 sf Runoff= 0.46 cfs 0.035 of Subcatchment 24S: AREA TRIB. TO AD#4,5,6 (COURTYARD) Tc =5.0 min CN =81 Area =5,547 sf Runoff= 0.37 cfs 0.024 of Subcatchment 25S: AREA TRIB. TO CB #3 Tc =5.0 min CN =82 Area =910 sf Runoff= 0.06 cfs 0.004 of Subcatchment 26S: AREA TRIB. TO CB #2 Tc =5.0 min CN =72 Area =7,720 sf Runoff= 0.36 cfs 0.024 of Reach 1 R: 12" RCP FROM EX. DMH TO OUTLET Inflow= 1.43 cfs 0.113 of Length= 94.0' Max Vel= 4.6 fps Capacity= 3.89 cfs Outflow= 1.41 cfs 0.113 of Reach 2R: 12" CI FROM EX. ROOF DRAINS TO EX. DMH Inflow= 1.47 cfs 0.113 of Length= 170.0' Max Vel= 4.1 fps Capacity= 3.31 cfs Outflow= 1.43 cfs 0.113 of Reach 3R: 15" HDPE FROM CB #14 TO CB #12 Inflow= 2.11 cfs 0.186 of Length= 100.0' Max Vel= 4.4 fps Capacity= 5.86 cfs Outflow= 2.09 cfs 0.186 of Reach 5R: DRAIN PIPE KING STREET TO DP #1 Inflow= 0.21 cfs 0.038 of Length= 290.0' Max Vel= 3.3 fps Capacity= 5.32 cfs Outflow= 0.21 cfs 0.038 of Reach 6R: 12" HDPE FROM CB #11 TO DMH #1 Inflow= 1.16 cfs 0.085 of Length= 66.0' Max Vel= 4.3 fps Capacity= 3.86 cfs Outflow= 1.14 cfs 0.085 of 60 -155 ROCKRIDGE POST F Type /// 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. I Page 74 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 26R: 12" HDPE FROM CB #6 TO DMH#4 Inflow= 0.16 cfs 0.011 of Length= 10.0' Max Vel= 2.4 fps Capacity= 3.86 cfs Outflow= 0.16 cfs 0.011 of Reach 28R: 12" HDPE FROM CB #7 TO DMH #5 Inflow= 0.51 cfs 0.035 of Length= 49.0' Max Vel= 3.9 fps Capacity= 4.71 cfs Outflow= 0.50 cfs 0.035 of Reach 29R: 12" HDPE FROM CB #8 TO DMH #5 Inflow= 0.61 cfs 0.056 of Length= 12.0' Max Vel= 3.6 fps Capacity= 3.86 cfs Outflow= 0.61 cfs 0.056 of Reach 30R: 12" HDPE FROM DCB #1 TO DMH #6 Inflow= 1.16 cfs 0.138 of Length= 20.0' Max Vel= 4.3 fps Capacity= 3.86 cfs Outflow= 1.16 cfs 0.138 of Reach 31R: 10" HDPE ROOF MANIFOLD Inflow= 0.46 cfs 0.035 of Length= 100.0' Max Vel= 3.3 fps Capacity= 2.37 cfs Outflow= 0.45 cfs 0.035 of Reach 32R: 10" HDPE ROOF MANIFOLD Inflow= 1.39 cfs 0.106 of Length= 200.0' Max Vel= 4.5 fps Capacity= 2.37 cfs Outflow= 1.34 cfs 0.106 of Reach 33R: 10" PVC ROOF DRAIN MANIFOLD Inflow= 1.42 cfs 0.105 of Length= 100.0' Max Vel= 5.6 fps Capacity= 3.17 cfs Outflow= 1.40 cfs 0.105 of Reach DP 10: DESIGN POINT #1 - 24" BOX CULVERT Inflow= 7.00 cfs 1.082 of Outflow= 7.00 cfs 1.082 of Reach DP 20: DESIGN POINT #2 - 30" RCP CULVERT Inflow= 0.19 cfs 0.040 of Outflow= 0.19 cfs 0.040 of Pond 1 P: UNDERGROUND DETENTION SYSTEM Peak Storage= 14,376 cf Inflow= 11.33 cfs 1.068 of Discarded= 0.35 cfs 0.347 of Primary= 4.59 cfs 0.673 of Secondary= 0.00 cfs 0.000 of Outflow= 4.94 cfs 1.020 of Pond 4R: 12" HDPE FROM CB#9 TO UNDERGROUND DETEH90RQk 19 cf Inflow= 0.90 cfs 0.065 of Primary= 0.90 cfs 0.064 of Outflow= 0.90 cfs 0.064 of Pond 11 R: 18" FROM DMH#8 TO DMH#9 Peak Storage= 13 cf Inflow= 4.74 cfs 0.436 of Primary= 4.74 cfs 0.436 of Outflow= 4.74 cfs 0.436 of Pond 12R: 18" HDPE FROM DMH#9 TO DMH #10 Peak Storage= 14 cf Inflow= 4.81 cfs 0.442 of Primary= 4.80 cfs 0.442 of Outflow= 4.80 cfs 0.442 of Pond 27R: 24" CMP FROM UNDERGROUND DETENTION T(YDM Wage= 14 cf Inflow= 2.86 cfs 0.315 of Primary= 2.86 cfs 0.314 of Outflow= 2.86 cfs 0.314 of Pond 35R: 24" CMP FROM DMH #10 TO UNDERGROUND DE1MTI8tt4WEAcf Inflow= 5.96 cfs 0.549 of Primary= 5.96 cfs 0.549 of Outflow= 5.96 cfs 0.549 of Runoff Area = 14.938 ac Volume = 1.518 of Average Depth = 1.22" 60 -155 ROCKRIDGE POST — F Type /// 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 76 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment IS: AREA TRIB. TO MAIN WETLAND AREA Hydrograph Plot RIM W w V 3 O LL — Runoff 1 z 3 4 5 6 / t$ 9 1U 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type /// 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 78 HydroCADO 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 3S: AREA TRIB. PROJECT SITE WEST Runoff = 2.11 cfs @ 12.21 hrs, Volume= 0.186 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description '— 21,785 98 Paved parking & drives 21,740 61 >75% Grass cover, Good, HSG B 437 98 Paved roofs — 43,962 80 Weighted Average Tc Length Slope Velocity Capacity Description — (min) (feet) (ft/ft) (ft/sec) (cfs) 14.6 70 0.0100 0.1 Sheet Flow, A -B Grass: Dense n= 0.240 P2= 3.00" 0.3 35 0.0100 2.0 Shallow Concentrated Flow, B -C — Paved Kv= 20.3 fps 0.3 75 0.0160 4.7 2.57 Circular Channel (pipe), C -D Diam= 10.0" Area= 0.5 sf Perim= 2.6' r= 0.21' n= 0.01 — 15.2 180 Total Subcatchment 3S: AREA TRIB. PROJECT SITE WEST Hydrograph Plot W w 3 O LL 1 — Runoff 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST _F Type 111 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 80 HydroCADO 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 314/2003 Subcatchment 5S: AREA TRIB. TO CB#9, 10 (EAST PARKING) Runoff = 0.90 cfs @ 12.07 hrs, Volume= 0.065 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 8,190 98 Paved parking 1,370 69 50 -75% Grass cover, Fair, HSG B 9,560 94 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Parking Lot Subcatchment 5S: AREA TRIB. TO CB#9, 10 (EAST PARKING) Hydrograph Plot v 3 0 LL -� Runoff 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST_F Type /// 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 82 HydroCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 7S: PROP. 3 -STORY BUILDING Runoff = 1.05 cfs @ 12.07 hrs, Volume= 0.081 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 10,615 98 Paved roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Roof Subcatchment 7S: PROP. 3 -STORY BUILDING Hydrograph Plot 1.05 cfs — Runoff - W 3 O LL 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST _F Type 111 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 84 HydroCADO 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 31412003 Subcatchment 9S: AREA TRIB. TO CB #1 Runoff = 0.57 cfs @ 12.16 hrs, Volume= 0.046 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 2,586 98 Paved driveway 6,323 69 50 -75% Grass cover, Fair, HSG B 11,924 55 Woods Good HSG B -- 20,833 65 Weighted Average Tc Length Slope Velocity Capacity Description _ (min) (feet) (ft/ft) (ft/sec) (cfs) 8.9 70 0.0950 0.1 Sheet Flow, A -B Woods: Light underbrush n= 0.400 P2= 3.00" 0.2 20 0.0700 1.9 Shallow Concentrated Flow, B -C `— Short Grass Pasture Kv= 7.0 fps 0.8 180 0.0320 3.6 Shallow Concentrated Flow, C -D Paved Kv= 20.3 fps 9.9 270 Total Subcatchment 9S: AREA TRIB. TO CB #1 Hydrograph Plot — Runoff W w 3 O LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type /// 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 86 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 11S: AREA TRIB. TO CB#8 Runoff = 0.61 cfs @ 12.20 hrs, Volume= 0.056 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description `- 2,185 69 50 -75% Grass cover, Fair, HSG B 3,556 98 Paved driveways 26,384 55 Woods, Good, HSG B 32,125 61 Weighted Average Tc — (min) Length (feet) Slope (ft/ft) Velocity (ft/sec) Capacity Description (cfs) 10.7 80 0.0800 0.1 Sheet Flow, A -B Woods: Light underbrush n= 0.400 P2= 3.00 ' 1.1 95 0.0800 1.4 Shallow Concentrated Flow, B-C Woodland Kv= 5.0 fps 0.1 20 0.1500 2.7 Shallow Concentrated Flow, C-D Short Grass Pasture Kv= 7.0 fps — 0.4 105 0.0380 4.0 Shallow Concentrated Flow, D -E Paved Kv= 20.3 fps 12.3 300 Total Subcatchment 11 S: AREA TRIB. TO CB#8 Hydrograph Plot — Runoff W 3 LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST_F Type /// 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 88 HydroCADO 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/412003 Subcatchment 13S: AREA TRIB. TO CB#12 Runoff = 0.39 cfs @ 12.07 hrs, Volume= 0.030 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 3,960 98 Paved parking & walks Tc Length Slope Velocity Capacity Description �- (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 13S: AREA TRIB. TO CB #12 Hydrograph Plot — Runoff W 3 O i LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 90 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 31412003 Subcatchment 15S: AREA TRIB. TO CB #14 Runoff = 0.45 cfs @ 12.07 hrs, Volume= 0.031 of — Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 3,933 98 Paved driveways 1,545 61 >75% Grass cover, Good, HSG B 5,478 88 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 15S: AREA TRIB. TO CB#14 Hydrograph Plot — Runoff W — 3 O LL. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type /// 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 92 HydroCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 17S: AREA TRIB. TO CB#4 Runoff = 0.36 cfs @ 12.07 hrs, Volume= 0.026 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 270 61 >75% Grass cover, Good, HSG B 3,532 98 Paved driveway & parking 3,802 95 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious i Subcatchment 17S: AREA TRIB. TO CB#4 Hydrograph Plot — Runoff LVMMMMMMMMA W — 3 O LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. Page 94 HydroCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 19S: AREA TRIB. TO CB #7 Runoff = 0.51 cfs @ 12.07 hrs, Volume= 0.035 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 4,570 98 Paved driveways & parking 1,610 61 >75% Grass cover, Good, HSG B 6,180 88 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (fttft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 19S: AREA TRIB. TO CB #7 Hydrograph Plot — Runoff N w V 3 O {l. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) Type /// 24 -hr Rainfall = 4.40" 60 -155 ROCKRIDGE POST _F Page 96 Prepared by Coler & Colantonio, Inc. 3/4 2003 H droCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcomputer Sy stems Subcatchment 21 S: AREA TRIB TO AD #2 & AD #3 Runoff = 0.08 cfs @ 12.09 hrs, Volume= 0.006 of _ Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" Area (sf) CN Description 2,810 61 >75% Grass cover, Good, HSG B 200 98 Paved atio 3,010 63 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec ) (cfs 4.3 30 0.0400 0.1 Sheet Flow, A -B Grass: Dense n= 0.240 P2= 3.00" 0.3 30 0.0800 2.0 Shallow Concentrated Flow, B-C Short Grass Pasture 4.6 60 Total Subcatchment 21S: AREA TRIB TO AD #2 & AD#3 U- Arnnranh Plot — Runoff N 3 O LL 0 1 2 3 4 5 ° V - Time (hours) 60 -155 ROCKRIDGE POST _F Prepared by Coler & Colantonio, Inc. uvrlrnr:An®R 6.00 s/n 001012 ©1986 - Type 111 24 -hr Rainfall = 4.40" Page 98 Subcatchment 23S: COTTAGES (114 TRIB. AREA) Runoff = 0.46 cfs @ 12.07 hrs, Volume= 0.035 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall =4.40" Area (sf) CN Description 4,664 98 Paved roofs Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 5.0 Direct Entry, Impervious Subcatchment 23S: COTTAGES (1/4 TRIB. AREA) u..rlrnnrnnh Plot — Runoff y w V 3 O LL D 0 1 2 3 4 5 b 1 0 Time (hours) 60 -155 ROCKRIDGE POST — F Prepared by Coler & Colantonio, Inc. Type 111 24 -hr Rainfall= 4.40" H drOCAD® 6.00 s/n 001012 © 1986 -2001 A lied Microcom uter S stems Page 100 Subcatchment 25S: AREA TRIB. TO CB #3 Runoff = 0.06 cfs @ 12.08 hrs, Volume= 0.004 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 4.40" --_ ArLea L(sfL CN Description 525 98 Paved driveways & walks 385 61 >75% Grass cover, Good HSG B 910 82 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft/ft) (ft/sec) (cfs) 50 Direct Entry, Imperious Subcat'chment 25S: AREA TRIB. TO CB #3 N w 3 O LL — Runoff Time (hours) " 10 17 18 19 20 60 -155 ROCKRIDGE POST — F Prepared by Cofer & Colantonio, Inc. HydrOCADO 6.00 s/n 0010 n 1 98 -2001 Type 111 24 -hr Rainfa# =4.40" S Page 102 Reach 1 R: 12" RCP FROM EX. DMH TO OUTLET Inflow = 1.43 cfs @ 12.09 hrs, Volume= Outflow = 1.41 cfs @ 12.10 hrs, Volume= 0.113 of 0.113 af, Atten= 1 °I °, Lag= 0.5 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.6 fps, Min. Travel Time= 0.3 min Avg. Velocity = 1.6 fps, Avg. Travel Time= 1.0 min Peak Depth= 0.42' Capacity at bank full= 3.89 cfs Inlet Invert= 190.80', Outlet Invert= 189.50' 12.0" Diameter Pipe n=0.014 Length= 94.0' Slope= 0.0138 '/' Reach 1 R: 12" RCP FROM EX. DMH TO OUTLET � N w V 3 O LL Inflow Outflow Time (hours) - "' ' ° I t 1 19 20 60 -155 ROCKRIDGE POST F Prepared by Coler & Colantonio, Inc. Hydr )CAD@ 6.00 s/n 00 1 012 ., . v � 9 86 -2001 Type 111 24 - hr Rainfall= 4.40" Page 104 Reach 3R: 15" HDPE FROM CB #14 TO CB412 Inflow = 2.11 cfs @ 12.21 hrs, Volume= Outflow = 2.09 cfs @ 12.22 hrs, Volume= 0.186 of 0.186 af, Atten= I%, Lag= 0.6 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.4 fps, Min. Travel Time= 0.4 min Avg. Velocity = 1.8 fps, Avg. Travel Time= 0.9 min Peak Depth= 0.52' Capacity at bank full= 5.86 cfs Inlet Invert= 196.80', Outlet Invert= 196.10' 15.0" Diameter Pipe n=0.012 Length= 100.0' Slope= 0.0070 7 Reach 3R: 15" HDPE FROM C13#14 TO CB #12 inflow — aumow Time (hours) -- " 11 10 It 18 19 20 � N w V 3 O LL inflow — aumow Time (hours) -- " 11 10 It 18 19 20 60 -155 ROCKRIDGE POST — F Prepared by Cofer & Colantonio, Inc. Type 111 24 -hr Rainfall= 4.40" H droCAD® 6.00 s/n 001012 © 1986 -2001 Applied Microcom ni itpr Rye tome Page 106 3/4/2003 Reach 6R: 12" HDPE FROM CB #11 TO DMH #1 Inflow = 1.16 cfs @ 12.12 hrs, Volume= 0.085 of Outflow = 1.14 cfs @ 12.13 hrs, Volume= 0.085 af, Atten= 2 %, Lag= 0.5 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.3 fps, Min. Travel Time= 0.3 min Avg. Velocity = 1.7 fps, Avg. Travel Time= 0.7 min Peak Depth= 0.38' Capacity at bank full= 3.86 cfs Inlet Invert= 198.13', Outlet Invert= 197.47' 12.0" Diameter Pipe n=0.012 Length= 66.0' Slope= 0.0100 '/' Reach 6R: 12" HDPE FROM CB #11 TO DMH #1 Hvdronranh Pl-* Inflow Outflow � y w V 3 O LL 1w 10 lb 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Prepared by Cofer & Colantonio, Inc. Type Ill 24 -hr Rainfall= 4.40" H droCADO 6.00 s/n 001012 © 1986 - 2001 Applie d Microcom uter S stems Page 108 3/4/2003 Reach 8R: 12" HDPE FROM CB #2 TO DMH #1 Inflow = 0.36 cfs @ 12.08 hrs, Volume= 0.024 of Outflow = 0.36 cfs @ 12.09 hrs, Volume= 0.024 af, Atten= 0 %, Lag= 0.2 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.9 fps, Min. Travel Time= 0.1 min Avg. Velocity = 1.6 fps, Avg. Travel Time= 0.3 min Peak Depth= 0.17' Capacity at bank full= 5.51 cfs Inlet Invert= 200.00 Outlet Invert= 199.43' 12.0" Diameter Pipe n=0.012 Length= 28.0' Slope= 0.0204 '/' Reach 8R: 12" HDPE FROM CB #2 TO DMH #1 Hvdroaranh Pint Inflow — Outflow w V 3 O LL Time (hours) '� �g 10 1b 17 18 19 20 60 -155 ROCKRIDGE POST F Prepared by Cofer & Colantonio, Inc. Type 111 24 -hr Rainfall= 4.40" H droCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcom uter S stems Page 110 3/4/2003 Reach 10R: 18" HDPE FROM DMH #7 TO DMH #8 Inflow = 4.50 cfs @ 12.16 hrs, Volume= 0.411 of Outflow = 4.49 cfs @ 12.16 hrs, Volume= 0.411 af, Atten= 0 %, Lag= 0.5 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 6.1 fps, Min. Travel Time= 0.3 min Avg. Velocity = 1.9 fps, Avg. Travel Time= 0.9 min Peak Depth= 0.66' Capacity at bank full= 11.38 cfs Inlet Invert= 195.67', Outlet Invert= 194.60' 18.0" Diameter Pipe n=0.012 Length= 107.0' Slope= 0.0100 7 Reach 10R: 18" HDPE FROM DMH #7 TO DMH #8 HvdrnnrnnJ, 01-* InflOW - oUtflOW N 3 O LL Time (hours) �� 14 �5 16 17 18 19 20 60 -155 ROCKRIDGE POST F Prepared by Cofer & Colantonio, Inc. HydroCAD® 6.00 s/n 001012 © 1986 2001 Type /// 24 -hr Rainfall =4.40" Page 112 Reach 14R: 12" HDPE FROM CB #13 TO DMH #8 Inflow = 0.36 cfs @ 12.07 hrs, Volume= 0.025 of Outflow = 0.35 cfs @ 12.08 hrs, Volume= 0.025 af, Atten= 2 %, Lag= 0.8 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.0 fps, Min. Travel Time= 0.4 min Avg. Velocity = 1.1 fps, Avg. Travel Time= 1.0 min Peak Depth= 0.20' Capacity at bank full= 3.86 cfs Inlet Invert= 198.47', Outlet Invert= 197.81' 12.0" Diameter Pipe n=0.012 Length= 66.0' Slope= 0.0100 '/' Reach 14R: 12" HDPE FROM CB#13 TO DMH #8 Hvdroaranh Pint N w V 3 O LL Inflow — Outflow Time (hours) 'j Iw 10 16 17 18 19 20 L 60 -155 ROCKRIDGE POST — F Prepared by Coler & Colantonio, Inc. Type 111 24 -hr Rainfall= 4.40" H droCADO 6.00 s/n 001012 0 1986 -2001 Applied Microcomputer Systems Page 114 3/4/2003 Reach 16R: 8" HDPE FROM YD #2 &3 TO DMH#9 Inflow = 0.08 cfs @ 12.09 hrs, Volume= 0.006 of Outflow = 0.08 cfs @ 12.09 hrs, Volume= 0.006 af, Atten= 0 %, La 0.3 9= rein Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 2.1 fps, Min. Travel Time= 0.1 min Avg. Velocity = 0.9 fps, Avg. Travel Time= 0.3 min Peak Depth= 0.11' Capacity at bank full= 1.31 cfs Inlet Invert= 200.00 Outlet Invert= 199.82' 8.0" Diameter Pipe n=0.012 Length= 18.0' Slope= 0.0100 '/' Reach 16R: 8" HDPE FROM YD#2 &3 TO DMH#9 Hvdroaranh Pint w V 3 O LL L Inflow Outflow 'Z 10 14 1b 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Prepared by Cofer & Colantonio Inc. Type 111 24 -hr Rainfall= 4.40" H droCADO 6.00 s/n 001012 © 1986 -2001 A lied Microcom uter S stems Page 116 3/4/2 03 Reach 18R: 12" HDPE FROM CB #3 TO DMH#2 Inflow = 0.06 cfs @ 12.08 hrs, Volume= 0.004 of Outflow = 0.06 cfs @ 12.08 hrs, Volume= o 0.004 af, Atten= 0%, Lag= 0.2 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 1.8 fps, Min. Travel Time= 0.1 min Avg. Velocity = 0.7 fps, Avg. Travel Time= 0.2 min Peak Depth= 0.09' Capacity at bank full= 3.86 cfs Inlet Invert= 205.67', Outlet Invert= 205.57' 12.0" Diameter Pipe n= 0.012 Length= 10.0' Slope= 0.0100 Reach 18R: 12" HDPE FROM CB #3 TO DMH #2 Hvdroaranh PI Inflow — Outflow N w V 3 O LL Time (hours) �� iw 13 16 17 18 19 20 60 -155 ROCKRIDGE POST F Prepared by Cofer & Colantonio, Inc. Type /// 24 -hr Rainfall= 4.40" H droCADO 6.00 s/n 001012 © 1986 - 2001 Applied Microcomputer Systems Page 118 3/4/2003 Reach 20R: 15" HDPE FROM DMH #3 TO DMH#4 Inflow = 0.86 cfs @ 12.12 hrs, Volume= Outflow = 0.85 cfs @ 12.13 hrs, Volume= 0075 of 0.075 af, Atten= 2 %, Lag= 0.5 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 6.0 fps, Min. Travel Time= 0.2 min Avg. Velocity = 2.1 fps, Avg. Travel Time= 0.6 min Peak Depth= 0.22' Capacity at bank full= 13.09 cfs Inlet Invert= 200.57', Outlet Invert= 198.05' 15.0" Diameter Pipe n=0.012 Length= 72.0' Slope= 0.0350 7' Reach 20R: 15" HDPE FROM DMH#3 TO DMH#4 Hvf1rnnrnnh 01-,, N V 3 O LL Inflow — Outflow Time (hours) w �� It 17 18 19 20 60 -155 ROCKRIDGE POST_F Prepared by Cofer & Colantonio, Inc. HydroCADO 6.00 s/n 00 1012 © 1986 - 200 , Type 111 24 -hr Rainfall= 4.40" Page 120 Reach 22R: 18" HDPE FROM DMH #5 TO DMH #6 Inflow = 1.92 cfs @ 12.13 hrs, Volume= 0.177 of Outflow = 1.91 cfs @ 12.14 hrs, Volume= 0.176 af, Atten= 0 %, Lag= 0.4 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.8 fps, Min. Travel Time= 0.2 min Avg. Velocity = 1.7 fps, Avg. Travel Time= 0.5 min Peak Depth= 0.41' Capacity at bank full= 11.50 cfs Inlet Invert= 195.10', Outlet Invert= 194.60' 18.0" Diameter Pipe n=0.012 Length= 49.0' Slope= 0.0102 '/' Reach 22R: 18" HDPE FROM DMH #5 TO DMH #6 Hvdrnnranh Dim w V 3 O LL — Inflow — Outflow Time (hours) '� '� 14 10 16 17 18 19 20 60 -155 ROCKRIDGE POST F Prepared by Cofer & Colantonio, Inc. Type 111 24 -hr Rainfall= 4.40" H droCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcom uter S stems Page 122 3/4/2003 Reach 25R: 12" HDPE FROM CB#5 TO DMH #3 Inflow = 0.52 cfs @ 12.17 hrs, Volume= 0.044 of Outflow = 0.52 cfs @ 12.17 hrs, Volume= 0.044 af, Atten= 0 %, Lag= 0.1 m,in Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.4 fps, Min. Travel Time= 0.0 min Avg. Velocity = 1.6 fps, Avg. Travel Time= 0.1 min Peak Depth= 0.25' Capacity at bank full= 3.86 cfs Inlet Invert= 202.02', Outlet Invert= 201.92' 12.0" Diameter Pipe n= 0.012 Length= 10.0' Slope= 0.0100 7 Reach 25R: 12" HDPE FROM CB#5 TO DMH #3 Hvdroaranh Pint Inflow — outflow w V 3 O LL Time (hours ) I 14 10 16 17 18 19 20 60 -155 ROCKRIDGE POST _F Prepared by Cofer & Colantonio, Inc. Type 111 24 -hr Rainfall= 4.40" H droCAD® 6.00 s/n 001012 © 1986 -2001 Appli ed Microcomputer Systems Page 124 3/4/2003 Reach 28R: 12" HDPE FROM CB #7 TO DMH #5 Inflow = 0.51 cfs @ 12.07 hrs, Volume= Outflow = 0.50 cfs @ 12.08 hrs, Volume= 0.035 of 0.035 af, Atten= 1 %, Lag= 0.5 min Routing by Stor - Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.9 fps, Min. Travel Time= 0.2 min Avg. Velocity = 1.4 fps, Avg. Travel Time= 0.6 min Peak Depth= 0.22' Capacity at bank full= 4.71 cfs Inlet Invert= 197.23', Outlet Invert= 196.50' 12.0" Diameter Pipe n=0.012 Length= 49.0' Slope= 0.0149 '/' Reach 28R: 12" HDPE FROM CB #7 TO DMH #5 Hvdrnnranh 01-f Inflow Outflow w V 3 O LL Time (hours) 10 It 18 19 20 60 -155 ROCKRIDGE POST — F Prepared by Coler & Colantonio, Inc. Type 111 24 -hr Rainfallg 126 H droCADO 6.00 s/n 001012 © 1986 -2001 A lied Microcom uter Systems Page 126 3/4/2003 Reach 30R: 12" HDPE FROM DCB #1 TO DMH #6 Inflow = 1.16 cfs @ 12.29 hrs, Volume= 0.138 of Outflow = 1.16 cfs @ 12.29 hrs, Volume= 0.138 af, Atten= 0 %, Lag= 0.2 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.3 fps, Min. Travel Time= 0.1 min Avg. Velocity = 1.8 fps, Avg. Travel Time= 0.2 min Peak Depth= 0.38' Capacity at bank full= 3.86 cfs Inlet Invert= 194.50', Outlet Invert= 194.30' 12.0" Diameter Pipe n=0.012 Length= 20.0' Stope= 0.0100 '/' Reach 30R: 12" HDPE FROM DCB #1 TO DMH #6 Hvdronrnnh Plnr Inflow — Outflow 3 O LL � Time (hours is 14 1b 16 17 18 19 20 60 -155 ROCKRIDGE POST _F Prepared by Coler & Colantonio, Inc. Type /// 24-hr Rallntall= 4.40" ` H droCADO 6.00 s/n 001012 © 1986 - 2001 Armlied Microcom uter S stems Page 128 3/4/2003 Reach 32R: 10" HDPE ROOF MANIFOLD Inflow = 1.39 cfs @ 12.07 hrs, Volume= 0.106 of Outflow = 1.34 cfs @ 12.10 hrs, Volume= ~ 0.106 af, Atten= 3 %, Lag= 1.5 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.5 fps, Min. Travel Time= 0.7 min Avg. Velocity = 1.6 fps, Avg. Travel Time= 2.1 min Peak Depth= 0.46' Capacity at bank full= 2.37 cfs -- Inlet Invert= 197.50', Outlet Invert= 195.50' 10.0" Diameter Pipe n=0.012 Length= 200.0' Slope= 0.0100 '/' ~ Reach 32R: 10" HDPE ROOF MANIFOLD HVdrnnranh D1 F Inflow Outflow w V 3 O LL Time (hours] '� 10 14 15 16 17 18 19 20 60 -155 ROCKRIDGE POST F Prepared by Coler & Colantonio, Inc. Type 111 24 -hr Rainfall= 4.40" H droCADO 6.00 s/n 001012 © 1986 -2001 Applied Microcom uter S stems Page 130 3/4/2003 Reach DP 10: DESIGN POINT #1 - 24" BOX CULVERT Inflow = 7.00 cfs @ 12.40 hrs, Volume= 1.082 of Outflow = 7.00 cfs @ 12.40 hrs, Volume= 1.082 af, Atten= 0 %, Lag= 0.0 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Reach DP 10: DESIGN POINT #1 - 24" BOX CULVERT Hvdroarnnh PI-t Inflow Outflow N w V 3 O LL Time (hours 10 15 17 18 19 20 ) 60 -155 ROCKRIDGE POST Routing Invert 1 - F Prepared by Cofer & Colantonio, Inc. 0.00' Type 111 24 - hr Rainfall= 4.40" H droCADO 6.00 s/n 001012 © 1986 -2001 Annliizfi Microcom uter S stems 3 Page 132 193.00' 4 Primary 3/4/2003 Pond 1P: UNDERGROUND DETENTION SYSTEM Secondary Inflow = 11.33 cfs @ 12.12 hrs, Volume= Outflow = 4.94 cfs @ 12.49 1.068 of hrs, Volume= Discarded = 0.35 cfs @ 10.20 hrs, Volume= 1.020 af, 0.347 Atten= 56 %, Lag= 22.8 min Primary = 4.59 cfs @ 12.49 hrs, Volume= Secondary = 0.00 cfs @ 0.00 hrs, of 0.673 of Volume= 0.000 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 9 Peak Elev= 193.86' Storage= 14,376 cf Plug -Flow detention time= 65.2 min calculated for 1 .0 18 of (95% of inflow) Storage and wetted areas determined by Irregular sections Elevation Surf.Area Perim. Open (feet) (sq -ft) (feet) Inc.Store Cum-Store Wet.Area ( %) (cubic- 190-50 7,000 610.0 30.0 ( c ub ic- c f e ) (s ft) 191.00 7,000 6100 300 . . 191.50 7,000 610.0 0 1,050 0 1,050 7,000 7,305 55.0 192.00 7,000 610.0 64.0 2,240 2 '975 7,610 192.50 7,000 610.0 68.0 193.00 7,000 610.0 2 5,215 7 7,915 8,220 71.0 193.50 7,000 610.0 72.0 2,520 10,080 8830 194.00 7,000 610.0 71.0 194.50 7,000 610.0 2 12,600 15,085 8,830 9,135 `- 68.0 195.00 7,000 610.0 64.0 2'380 17,465 9,440 195.50 7,000 610.0 55.0 195.90 7,000 610.0 1,925 19,705 21 ,630 9,745 10,050 30.0 _. 196.00 7,000 610.0 30.0 840 210 22,470 10,294 22,680 10,355 Qiscarded OutFlow (Free Discharge) � Exfiltration Primary OutFlow (Free Discharge) 2= Orifice /Grate �-- 3= Orifice /Grate = Orifice /Grate 2econdary OutFlow (Free Discharge) = Orifice /Grate # Routing Invert 1 Discarded 0.00' 2 Primary 191.20' 3 Primary 193.00' 4 Primary 192.00' 5 Secondary 195.00' Outlet Devices u.uu3000 fpm Exfiltration over entire Surface area 6.0" Vert. Orifice /Grate C= 0.600 10.0" Vert. Orifice /Grate C= 0.600 0.17'x 3.00' Vert. Orifice /Grate C= 0.600 30.0" Horiz. Orifice /Grate Limited to weir flow C= 0.600 60 -155 ROCKRIDGE POST F Prepared by Coler & Colantonio, Inc. HydroCAD® 6.00 s/n 001012 ©1986 -2001 Type 111 24 -hr Rainfall= 4.40" Page 134 Pond 4R: 12" HDPE FROM CB#9 TO UNDERGROUND DETENTION AREA Inflow = 0.90 cfs @ 12.07 hrs, Volume= Outflow = 0.90 cfs @ 12.07 hrs, Volume= 0.065 of Primary = 0.90 cfs @ 12.07 hrs, Volume= 0.064 af, 0.064 of Atten= 0 %, Lag= 0.1 min Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs O `- Peak Elev= 194.35' Storage= 19 cf LL Plug -Flow detention time= 4.4 min calculated for 0.064 of (99% Storage and wetted areas determined of inflow) by Conic sections 0 I Elevation Surf.Area Inc.Store Cum-Store (feet) Wet.Area (sq -ft) (cubic feet) (cubic feet) 192.75 (s ft _ 192.76 12 0 0 0 0 193.00 12 3 0 3 12 194.00 12 12 15 15 `- 195.00 12 27 196.00 12 1 2 39 4 52 �.. Primary OutFlow (Free Discharge) 't--1 =Culvert # Routing 1 Primary 193.76' 12.0" x 120.0' long Culvert CMP, square edge headwall, Ke= 0.500 Outlet Invert= 192.17' S= 0.0132 'P n= 0.024 Cc= 0.900 Pond 4R: 12" HDPE FROM CB#9 TO UNDERGROUND DETENTION AREA Hvdroaranh Pint — Inflow — Primary 14 113 14 1b 16 17 18 19 20 Time (hours) H w V 3 O �-- LL 0 I 193.76' 12.0" x 120.0' long Culvert CMP, square edge headwall, Ke= 0.500 Outlet Invert= 192.17' S= 0.0132 'P n= 0.024 Cc= 0.900 Pond 4R: 12" HDPE FROM CB#9 TO UNDERGROUND DETENTION AREA Hvdroaranh Pint — Inflow — Primary 14 113 14 1b 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Prepared by Coler & Colantonio, Inc. Type /// 24 -hr Rainfall 136 H droCAD® 6.00 s/n 001012 ©1986 -2001 A lied Microcomputer Systems Page 136 3/4/2003 Pond 12R: 18" HDPE FROM DMH#9 TO DMH #10 Inflow = 4.81 cfs @ 12.16 hrs, Volume= 0.442 of Outflow = 4.80 cfs @ 12.16 hrs, Volume= 0.442 af, Atten= 0 %, Lag= 0.0 min Primary = 4.80 cfs @ 12.16 hrs, Volume= 0.442 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 5 Peak Elev= 194.68' Storage= 14 cf Plug -Flow detention time= 0.1 min calculated for 0.442 of (100% of inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum-Store Wet.Area feet (sq -ft 193.51 ) (cubic -feet) (cubic feet) (sq ft) 193.52 12 0 0 0 194.00 12 12 195.00 12 12 6 6 1 8 196.00 12 18 30 197.00 12 12 42 42 55 Primary OutFlow (Free Discharge) L1 = Culvert # Routing Invert Outlet Devices 1 Primary 193.57' 18.0" x 50.0' long Culvert RCP, sq.cut end projecting, Ke= 0.500 Outlet Invert= 193.07' S= 0.0100 '/' n=0.012 Cc= 0.900 Pond 12R: 18" HDPE FROM DMH#9 TO DMH #10 Hvdroaranh Pint — Inflow — Primary 2 1 0 O a 1u 11 12 13 14 15 16 17 18 19 20 Time (hours) to v 3 0 LL 2 1 0 O a 1u 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type Ill 24 -hr Rainfall= 4.40" Prepared by Coler & Colantonio, Inc. HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems Page 138 3/4/2003 Pond 35R: 24" CMP FROM DMH #10 TO UNDERGROUND DETENTION AREA Inflow = 5.96 cfs @ 12.13 hrs, Volume= 0.549 of Outflow = 5.96 cfs @ 12.13 hrs, Volume= 0.549 af, Atten= 0 %, Lag= 0.0 min Primary = 5.96 cfs @ 12.13 hrs, Volume= 0.549 of Routing by Stor -Ind method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs / 5 Peak Elev= 194.36' Storage= 8 cf Plug -Flow detention time= (not calculated: outflow precedes inflow) Storage and wetted areas determined by Conic sections Elevation Surf.Area Inc.Store Cum-Store Wet.Area feet (sq -ft) (cubic -feet) (cubic feet) (sq ft) 193.69 0 0 0 0 193.70 12 0 0 12 194.00 12 4 4 16 195.00 12 12 16 28 196.00 12 12 28 40 Primary OutFlow (Free Discharge) t-- =Culvert # Routing Invert Outlet Devices _ 1 Primary 193.04' 24.0" x 34.0' long Culvert CMP, square edge headwall, Ke= 0.500 Outlet Invert= 192.70' S= 0.0100 T n= 0.024 Cc= 0.900 Pond 35R: 24" CMP FROM DMH #10 TO UNDERGROUND DETENTION AREA Hvdroaranh Plot L Inflow Primary w v 3 0 U. Ii 0 v a iu 11 12 13 14 15 16 17 18 19 20 Time (hours) co F I C Q I R' C-7�1 I N 1 70-: _D L O " u cg) \� N E m L F- m CD ONE a: �� O U 0 Y U o �U c a I 'E a O C CV O CD U r . �.o0© E cc 6 IbN c L ea a oo, U 0 J c 0 [ I ] v L`I T 1 I N 1 70-: _D L O " u cg) \� N E m L F- m CD ONE a: �� O U 0 Y U o �U c a I 'E a O C CV O CD U r . �.o0© E cc 6 IbN c L ea a oo, U 0 J c 0 [ I ] 60 -155 ROCKRIDGE POST F Prepared by Coler & Colantonio, Inc. HydroCAD® 6.00 s/n 001012 ®1986 -2001 Subcatchment 16S: AREA TRIB. TO AD #1 - Subcatchment 17S: AREA TRIB. TO CB#4 Subcatchment 18S: AREA TRIB. TO CB #6 Subcatchment 19S: AREA TRIB. TO CB #7 Type 111 24 -hr Rainfall =5.40" Page 141 Tc =4.4 min CN =66 Area =4,760 sf Runoff= 0.26 cfs 0.017 of Tc =5.0 min CN =95 Area =3,802 sf Runoff= 0.45 cfs 0.033 of Tc =5.0 min CN =90 Area =1,823 sf Runoff= 0.20 cfs 0.014 of Tc =5.0 min CN =88 Area =6,180 sf Runoff= 0.66 cfs 0.045 of Subcatchment 20S: AREA TRIB. TO DCB#1 Tc =5.0 min CN =87 Area =5,767 sf Runoff= 0.60 cfs 0.041 of Subcatchment 21S: AREA TRIB TO AD#2 & AD#3 Tc=4.6 min CN =63 Area =3,010 sf Runoff= 0.14 cfs 0.009 of Subcatchment 22S: COTTAGES (3/4 TRIB. AREA) Outflo 1.73 cfs 0.140 of Tc =5.0 min CN =98 Area= 13,991 sf Runoff= 1.71 cfs 0.132 of Subcatchment 23S: COTTAGES (1/4 TRIB. AREA) Length= 170.0' Max Vel= 4.3 fps Tc =5.0 min CN =98 Area =4,664 sf Runoff= 0.57 cfs 0.044 of Subcatchment 24S: AREA TRIB. TO AD#4,5,6 (COURTYARD) Tc =5.0 min CN =81 Area =5,547 sf Runoff= 0.50 cfs 0.033 of Subcatchment 25S: AREA TRIB. TO CB#3 Outflow= 2.86 cfs 0.254 of Tc =5.0 min CN =82 Area =910 sf Runoff= 0.08 cfs 0.006 of Subcatchmert 26S: AREA TRIB. TO CB#2 Tc =5.0 min CN =72 Area =7,720 sf Runoff= 0.52 cfs 0.034 of Reach 1 R: 12" RCP FROM EX. DMH TO OUTLET Length = 94.0' Max Vel= 4.8 fps Capacity= 3.89 cfs Outflo 1.73 cfs 0.140 of Reach 2R: 12" Cl FROM EX. ROOF DRAINS TO EX. DMH Inflow= 1.81 cfs 0.140 of Length= 170.0' Max Vel= 4.3 fps Capacity= 3.31 cfs Outflow= 1.76 cfs 0.140 of Reach 3R: 15" HDPE FROM CB#14 TO CB#12 Length= 100.0' Max Vel= 4.7 fps Capacity= 5.86 cfs Outflow= 2.86 cfs 0.254 of Reach 5R: DRAIN PIPE KING STREET TO DP #1 Length= 290.0' Max Vel= 4.5 fps Capacity= 5.32 cfs Inflow-- 0.59 c f s 0.079 af Outflow= 0.59 cfs 0.079 of Reach 6R: 12" HDPE FROM CB#11 TO DMH #1 Length= 66.0' Max Vel= 4.6 fps Capacity= 3.86 cfs Inflow= 1.55 c f s 0.114 af Outflow= 1.52 cfs 0.114 of 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall =5.40" Page 143 Reach 28R: 12" HDPE FROM CB#7 TO DMH #5 Inflow= 0.66 cfs 0.045 of Length= 49.0' Max Vel= 4.2 fps Capacity= 4.71 cfs Outflow= 0.65 cf$ 0.045 of Reach 29R: 12" HDPE FROM CB#8 TO DMH #5 Inflow= 1.04 cfs 0.090 of Length= 12.0' Max Vel= 4.2 fps Capacity= 3.86 cfs Outflow= 1.04 cfq 0.090 of Reach 30R: 12" HDPE FROM DCB#1 TO DMH #6 Length= 20.0' Max Vel= 4.9 fps Capacity= 3.86 cfs Inflow= 1.95 cfs 0.214 of Outflow= 1.95 cfs 0.214 of Reach 31R: 10" HDPE ROOF MANIFOLD Length= 100.0' Max Vel= 3.5 fps Capacity= 2.37 cfs Inflow= 0.57 cfs 0.044 of Outflow= 0.56 cfs 0.044 of Reach 32R: 10" HDPE ROOF MANIFOLD Length= 200.0' Max Vel= 4.7 fps Capacity= 2.37 cfs Inflow= 1.71 cfs 0.132 of Outflow= 1.65 cfs 0.132 of Reach 33R: 10" PVC ROOF DRAIN MANIFOLD Length= 100.0' Max Vel= 5.9 fps Capacity= 3.17 cfs Inflow= 1.80 cfs 0.133 of Outflow= 1.77 cfs 0.133 of Reach DP 10: DESIGN POINT #1 - 24" BOX CULVERT Inflow= 11.97 cfs 1.688 of Outflow= 11.97 cfs 1.688 of Reach DP 20: DESIGN POINT#2 - 30" RCP CULVERT Inflow= 0.61 cfs 0.089 of Outflow= 0.61 cfs 0.089 of Pond 1P: UNDERGROUND DETENTION SYSTEM Peak Storage= 18,747 cf Inflow= 15.68 cfs 1.469 of Discarded= 0.35 cfs 0.370 of Primary= 7.34 cfs 1.041 of Secondary= 0.00 cfs 0.000 of Outflow= 7.69 cfs 1.411 of Pond 4R: 12" HDPE FROM CB#9 TO UNDERGROUND DETER901514kRJEot 20 cf Inflow= 1.13 cfs 0.082 of Primary= 1.13 cfs 0.081 of Outflow= 1.13 cfs 0.081 of Pond 11R: 18" FROM DMH#8 TO DMH#9 Pond 12R: 18" HDPE FROM DMH#9 TO DMH#10 Peak Storage= 16 cf Inflow= 6.55 cfs 0.599 of Primary= 6.55 cfs 0.599 of Outflow= 6.55 cfs 0.599 of Peak Storage= 17 cf Inflow= 6.65 cfs 0.608 of Primary= 6.65 cfs 0.608 of Outflow= 6.65 cfs 0.608 of Pond 27R: 24" CMP FROM UNDERGROUND DETENTION TCPDM18Wage= 17 cf Inflow= 4.53 cfs 0.471 of Primary= 4.53 cfs 0.471 of Outflow= 4.53 cfs 0.471 of Pond 35R: 24" CMP FROM DMH #10 TO UNDERGROUND DE cf Inflow= 8.08 cfs 0.740 of Primary= 8.08 cfs 0.740 of Outflow= 8.08 cfs 0.740 of Runoff Area = 14.938 ac Volume = 2.206 of Average Depth =1.77" 11 Reach 26R: 12" HDPE FROM CB#6 TO DMH#4 Inflow= 0.20 cfs 0.014 of Length= 10.0' Max Vel= 2.6 fps Capacity= 3.86 cfs Outflow= 0.20 cfs 0.014 of s� 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 145 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 1S: AREA TRIB. TO MAIN WETLAND AREA Hydrograph Plot w v 3 0 LL w iv II 1z 1s 14 15 16 17 18 19 20 Time (hours) — Runoff 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 147 HydroCAD® 6.00 s/n 001012 ®1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 3S: AREA TRIB. PROJECT SITE WEST Runoff = 2.88 cfs @ 12.21 hrs, Volume= 0.255 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall =5.40" Area (sf) CN Description 21,785 98 Paved parking & drives 21,740 61 >75% Grass cover, Good, HSG B 437 98 Paved roofs `- 43,962 80 Weighted Average Tc Length Slope Velocity Capacity Description _. (min) (feet) (ft/ft) (ft/sPC) (cfs) 14.6 70 0.0100 0.1 Sheet Flow, A -B Grass: Dense n= 0.240 P2= 3.00" 0.3 35 0.0100 2.0 Shallow Concentrated Flow, B-C Paved Kv= 20.3 fps 0.3 75 0.0160 4.7 2.57 Circular Channel (pipe), C -D Diam= 10.0" Area= 0.5 sf Perim= 2.6' r= 0.21' n= 0.014 15.2 180 Total Subcatchment 3S: AREA TRIB. PROJECT SITE WEST Hydrograph Plot 3 0 LL — Runoff o V w Ii 1L 1s 14 1b 15 17 18 19 20 Inme (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainifall =5.40" Prepared by Coler & Colantonio, Inc. Page 149 HydroCAD@ 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 31412003 Subcatchment 5S: AREA TRIB. TO CB#9, 10 (EAST PARKING) Runoff = 1.13 cfs @ 12.07 hrs, Volume= 0.082 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall = 5.40" Area (sf) CN Description 8,190 98 Paved parking 1,370 69 50 -75% Grass cover. Fair HSG B 9,560 94 Weighted Average Tc Length Slope Velocity Capacity Description min (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Parking Lot Subcatchment 5S: AREA TRIB. TO CM, 10 (EAST PARKING) Hvdroaranh Plot — Runoff 3 0 LL Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 151 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 7S: PROP. 3 -STORY BUILDING Runoff = 1.30 cfs @ 12.07 hrs, Volume= 0.100 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall = 5.40" Area (sf) CN Description 10,615 98 Paved roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Roof Subcatchment 7S: PROP. 3 -STORY BUILDING Hydrograph Plot v 3 0 LL — Runoff y a o i a V lU 11 lz 13 14 15 16 17 18 19 20 Tlme (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall= 5.40" Prepared by Coler & Colantonio, Inc. Page 153 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 9S: AREA TRIB. TO CB#1 Runoff = 0.90 cfs @ 12.15 hrs, Volume= 0.070 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall = 5.40" Area (sf) CN Description 2,586 98 Paved driveway 6,323 69 50 -75% Grass cover, Fair, HSG B 11,924 55 Woods, Good, HSG B 20,833 65 Weighted Average Tc (min) Length (feet) Slope (ft/ft) Velocity (ft/sec) Capacity Description (cfs) 8.9 70 0.0950 0.1 Sheet Flow, A -B Woods: Light underbrush n= 0.400 P2= 3.00" 0.2 20 0.0700 1.9 Shallow Concentrated Flow, B-C Short Grass Pasture Kv= 7.0 fps 0.8 180 0.0320 3.6 Shallow Concentrated Flow, C -D Paved Kv= 20.3 fps -- 9.9 270 Total Subcatchment 9S: AREA TRIB. TO CB#1 ` Hydrograph Plot J !- . v r o U IV 11 1z 13 14 15 16 17 18 19 20 Time (hours) — Runoff w 3 0 LL J !- . v r o U IV 11 1z 13 14 15 16 17 18 19 20 Time (hours) — Runoff 60 -155 ROCKRIDGE POST — F Prepared by Coler & Colantonio, Inc. �— HydroCAD® 6 .00 s/n 001012 ©1986 -2001 Type/// 24 -hr Rainfall =5.40" Page 155 '41APD IA Subcatchment 11S: AREA TRIB. TO CB#8 1 Subcatchment 11 S: AREA TRIB. TO CB#8 Hydrograph Plot Runoff = 1.04 cfs @ 12.19 hrs, Volume= 0.090 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall =5.40" Area (sf) CN Description 2,185 w 3,556 98 Paved driveways 26,384 55 Woods, Good, HSG B 32,125 3 Tc Length -- o (min) (feet) (ft/ft) (ft/sec) (cfs) LL 0.0800 0.1 Sheet Flow, A -B - —r Woods: Light underbrush n= 0.400 P2= 3.00" 1.1 95 0.0800 1.4 Shallow Concentrated Flow, B -C 0 Runoff = 1.04 cfs @ 12.19 hrs, Volume= 0.090 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall =5.40" Area (sf) CN Description 2,185 69 50 -75% Grass cover, Fair, HSG B 3,556 98 Paved driveways 26,384 55 Woods, Good, HSG B 32,125 61 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.7 80 0.0800 0.1 Sheet Flow, A -B - —r Woods: Light underbrush n= 0.400 P2= 3.00" 1.1 95 0.0800 1.4 Shallow Concentrated Flow, B -C Woodland Kv= 5.0 fps 0.1 20 0.1500 2.7 Shallow Concentrated Flow, C -D Short Grass Pasture Kv= 7.0 fps 0.4 105 0.0380 4.0 Shallow Concentrated Flow, D -E Paved Kv= 20.3 fps 12.3 300 Total U v i o a 1u 11 12 13 14 15 16 17 18 19 20 Time (hours) — Runoff 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 157 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 13S: AREA TRIB. TO CB#12 Runoff = 0.48 cfs @ 12.07 hrs, Volume= 0.037 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall =5.40" Area (sf) CN Description 3,960 98 Paved parking & walks Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 13S: AREA TRIB. TO CB#12 Hydrograph Plot — Runoff w 3 0 LL is 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 11124 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 159 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 15S: AREA TRIB. TO CB#14 Runoff = 0.58 cfs @ 12.07 hrs, Volume= 0.040 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall =5.40" Area (sf) CN Description 3,933 98 Paved driveways 1,545 61 >75% Grass cover, Good, HSG B 5,478 88 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 15S: AREA TRIB. TO CB#14 Hydrograph Plot — Runoff 'a w 3 0 LL U 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 161 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 17S: AREA TRIB. TO CM Runoff = 0.45 cfs @ 12.07 hrs, Volume= 0.033 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall = 5.40" Area (sf) CN Description 270 61 >75% Grass cover, Good, HSG B 3,532 98 Paved driveway & parking 3,802 95 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 17S: AREA TRIB. TO CB" Hydrograph Plot — Runoff w 0 LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE. POST —F Type 111 24-hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 1 HydroCAD® 63 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2063 Subcatchment 19S: AREA TRIB. TO CB#7 Runoff = 0.66 cis @ 12.07 hrs, Volume= 0.045 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall =5.40" Area (sf) CN Description 4,570 98 Paved driveways & parking 1.610 61 >75% Grass cover Good HSG B 6,180 88 Weighted Average Tc Length Slope Velocity Capacity Description ...\ - it - % ,..,... - - 5.0 Direct Entry, Impervious Subcatchment 19S: AREA TRIB. TO CB#7 Hydrograph Plot — Runoff w 3 0 LL Time (hours) - -- 60 -155 ROCKRIDGE POST F Prepared by Coler & Colantonio, Inc. HydroCAD® 6.00 s/n 001012 © 1986 -2001 Type 111 24 -hr Rainfa# =5.40" Page 165 Subcatchment 21S: AREA TRIB TO AD#2 & AD #3 Runoff = 0.14 cfs @ 12.08 hrs, Volume= 0.009 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall =5.40" Area (sf) CN Description 2,810 61 >75% Grass cover, Good, HSG B 200 98 Paved patio 3,010 63 Weighted Average Tc Length Slope Velocity Capacity Description min feet ft/ft) (ft/sec) (cfs) — 4.3 30 0.0400 0.1 Sheet Flow, A -B 0.3 30 Grass: Dense n= 0.240 P2= 3.00" 0.0800 2.0 Shallow Concentrated Flow, 4.6 60 B -C Total Short Grass Pasture Kv= 7.0 f s Subcatchment 21S: AREA TRIB TO AD#2 & AD#3 Hvdronranh Plnt w 3 0 LL — Runoff iJ Iw 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type ll/ 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 167 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Subcatchment 23S: COTTAGES (1/4 TRIB. AREA) Runoff = 0.57 cfs @ 12.07 hrs, Volume= 0.044 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall= 5.40" Area (sf) CN Description 4,664 98 Paved roofs Tc Length Slope Velocity Capacity Description tminl /f-- +% /"IZA% 1111_ _ 5.0 Direct Entry, Impervious Subcatchment 23S: COTTAGES (1/4 TRIB. AREA) Hvdroaranh Pint — Runoff 3 0 LL 6— 1_ - 1C 13 14 10 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 169 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 2003 Subcatchment 25S: AREA TRIB. TO CB#3 Runoff = 0.08 cfs @ 12.08 hrs, Volume= 0.006 of Runoff by SCS TR -20 method, UH =SCS, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Type III 24 -hr Rainfall = 5.40" Area (sf) CN Description 525 98 Paved driveways & walks 385 61 >75% Grass cover Good HSG B 910 82 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Impervious Subcatchment 25S: AREA TRIB. TO CB#3 Hvdroaranh Plnt — Runoff w 3 0 LL 6— IL 1J 74 10 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 171 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 1 R: 12" RCP FROM EX. DMH TO OUTLET Inflow = 1.76 cfs @ 12.09 hrs, Volume= 0.140 of Outflow = 1.73 cfs @ 12.10 hrs, Volume= 0.140 af, Atten= 11%, Lag= 0.5 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.8 fps, Min. Travel Time= 0.3 min Avg. Velocity = 1.7 fps, Avg. Travel Time= 0.9 min Peak Depth= 0.47' Capacity at bank full= 3.89 cfs Inlet Invert= 190.80', Outlet Invert= 189.50' 12.0" Diameter Pipe n=0.014 Length= 94.0' Slope= 0.0138 '/' Reach 1 R: 12" RCP FROM EX. DMH TO OUTLET Hydrouraph Plot Inflow outflow a 3 0 LL 14 10 14 lb 16 17 18 19 20 Time (hours) 6- L_ 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 173 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 3R: 15" HDPE FROM CB#14 TO CB#12 Inflow = 2.88 cfs @ 12.21 hrs, Volume= 0.255 of Outflow = 2.86 cfs @ 12.22 hrs, Volume= 0.254 af, Atten= I%, Lag= 0.6 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.7 fps, Min. Travel Time= 0.4 min Avg. Velocity = 2.0 fps, Avg. Travel Time= 0.8 min Peak Depth= 0.62' Capacity at bank full= 5.86 cfs Inlet Invert= 196.80', Outlet Invert= 196.10' 15.0" Diameter Pipe n=0.012 Length= 100.0' Slope= 0.0070 '/' Reach 3R: 15" HDPE FROM CB#14 TO CB#12 Hvdroaranh Pint Inflow — outflow r.. 3 0 LL v IV I I I z l3 14 15 16 17 18 19 20 Time (hours) • 60 -155 ROCKRFDGE POST F Type 111 24 -hr Rainfall= 5.40" Prepared by Coler & Colantonio, Inc. I Page 175 HydroCADO 6.00 s/n 001012 ©1986 -2001 A I' d M' UU le Icrocomputer Systems Reach 6R: 12" HDPE FROM CB#11 TO DMH #1 Inflow = 1.55 cfs @ 12.12 hrs, Volume= 0.114 of Outflow = 1.52 cfs @ 12.13 hrs, Volume= 0.114 af, Atten= 2 %, Lag= 0.5 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.6 fps, Min. Travel Time= 0.2 min Avg. Velocity = 1.8 fps, Avg. Travel Time= 0.6 min Peak Depth= 0.44' Capacity at bank full= 3.86 cfs Inlet Invert= 198.13', Outlet Invert= 197.47' 12.0" Diameter Pipe n=0.012 Length= 66.0' Slope= 0.0100 '/' Reach 6R: 12" HDPE FROM CB#11 TO DMH #1 Hydrograah Plot w 3 0 LL — Inflow — Outflow IV I 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type /// 24 -hr Rainfiall =5.40" Prepared by Coler & Colantonio, Inc. Page 177 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 8R: 12" HDPE FROM CB#2 TO DMH #1 Inflow = 0.52 cfs @ 12.08 hrs, Volume= 0.034 of Outflow = 0.52 cfs @ 12.08 hrs, Volume= 0.034 af, Atten= 0 %, Lag= 0.2 min Routing by Stor - Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.4 fps, Min. Travel Time= 0.1 min Avg. Velocity = 1.7 fps, Avg. Travel Time= 0.3 min Peak Depth= 0.21' Capacity at bank full= 5.51 cfs •- Inlet Invert= 200.00 Outlet Invert= 199.43' 12.0" Diameter Pipe n= 0.012 Length= 28.0' Slope= 0.0204T Reach 8R: 12" HDPE FROM CB#2 TO DMH #1 Hydrociraoh Plot Inflow Outflow I iy 1 25 19 20 Time (hours) w 3 0 LL I iy 1 25 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall= 5.40" Prepared by Coler & Colantonio, Inc. Page 179 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 10R: 18" HDPE FROM DMH #7 TO DMH#8 Inflow = 6.25 cfs @ 12.15 hrs, Volume= 0.567 of Outflow = 6.23 cfs @ 12.16 hrs, Volume= 0.567 af, Atten= 0 %, Lag= 0:5 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 6.6 fps, Min. Travel Time= 0.3 min Avg. Velocity = 2.1 fps, Avg. Travel Time= 0.8 min Peak Depth= 0.79' Capacity at bank full= 11.38 cfs Inlet Invert= 195.67', Outlet Invert= 194.60' 18.0" Diameter Pipe n=0.012 Length= 107.0' Slope= 0.0100 '/' Reach 10R: 18" HDPE FROM DMH #7 TO DMH#8 Hydroaraph Plot Inflow outflow 3 0 U. U IV II 1Z is 14 15 16 17 18 19 20 Time (hours) L 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 181 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems ag 103 Reach 14R: 12" HDPE FROM CB #13 TO DMH#8 Inflow = 0.45 cfs @ 12.07 hrs, Volume= 0.032 of Outflow = 0.44 cfs @ 12.08 hrs, Volume= 0.032 af, Atten= 2 %, Lag= 0.7 min L Routing by Stor - Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 3.2 fps, Min. Travel Time= 0.3 min Avg. Velocity = 1.1 fps, Avg. Travel Time= 1.0 min Peak Depth= 0.23' Capacity at bank full= 3.86 cfs Inlet Invert= 198.47', Outlet Invert= 197.81' 12.0" Diameter Pipe n=0.012 Length= 66.0' Slope= 0.0100 7 Reach 14R: 12" HDPE FROM CM 3 TO DMH#8 Hvdrnnranh Dlnf Inflow — Outflow w 3 0 LL i U lu 11 1Z 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type /// 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 183 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 16R: 8" HDPE FROM YD#2 &3 TO DMH#9 Inflow = 0.14 cfs @ 12.08 hrs, Volume= 0.009 of Outflow = 0.14 cfs @ 12.08 hrs, Volume= 0.009 af, Atten= 0 %, Lag= 0.3 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 2.4 fps, Min. Travel Time= 0.1 min Avg. Velocity = 1.0 fps, Avg. Travel Time= 0.3 min Peak Depth= 0.15' Capacity at bank full= 1.31 cfs Inlet Invert= 200.00', Outlet Invert= 199.82' 8.0" Diameter Pipe n=0.012 Length= 18.0' Slope= 0.0100 '/' Reach 16R: 8" HDPE FROM YD#2 &3 TO DMH#9 Hvdrouraoh Plot — Inflow — Outflow w 3 0 LL IV I 14 15 16 17 18 19 20 Time (hours) L 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems Page 185 3/4/2003 Reach 18R: 12" HDPE FROM CB#3 TO DMH#2 Inflow = 0.08 cfs @ 12.08 hrs, Volume= 0.006 of Outflow = 0.08 cfs @ 12.08 hrs, Volume= 0.006 af, Atten= 0 %, Lag= 0.2 min Routing by Stor -Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 2.0 fps, Min. Travel Time= 0.1 min Avg. Velocity = 0.7 fps, Avg. Travel Time= 0.2 min Peak Depth= 0.10' Capacity at bank full= 3.86 cfs Inlet Invert= 205.67', Outlet Invert= 205.57' 12.0" Diameter Pipe n=0.012 Length= 10.0' Slope= 0.0100 7 Reach 18R: 12" HDPE FROM CM TO DMH #2 Hydrocirar)h Plot Inflow — outflow w 41 3 0 LL IV 11 1z 13 14 15 16 17 18 19 20 Time (hours) L 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rain fall =5.40" Prepared by Coler & Colantonio, Inc. H droCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems Page 187 3/4/200,3 Reach 20R: 15" HDPE FROM DMH#3 TO DMH#4 Inflow = 1.27 cfs @ 12.13 hrs, Volume= 0.108 of Outflow = 1.27 cfs @ 12.13 hrs, Volume= 0.108 af, Atten= 0 %, Lag= 0.5 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 6.7 fps, Min. Travel Time= 0.2 min Avg. Velocity = 2.3 fps, Avg. Travel Time= 0.5 min Peak Depth= 0.26' Capacity at bank full= 13.09 cfs Inlet Invert= 200.57', Outlet Invert= 198.05' 15.0" Diameter Pipe n= 0.012 Length= 72.0' Slope= 0-03507' Reach 20R: 15" HDPE FROM DMH#3 TO DMH#4 Hvdroaranh Pint inflow — outflow 'G 3 0 LL IV II 1z - is 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 189 ydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 22R: 18" HDPE FROM DMH #5 TO DMH#6 Inflow = 2.90 cfs @ 12.14 hrs, Volume= 0.257 of Outflow = 2.89 cfs @ 12.14 hrs, Volume= 0.257 af, Atten= 0 %, Lag= 0.3 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 5.4 fps, Min. Travel Time= 0.2 min Avg. Velocity = 1.8 fps, Avg. Travel Time= 0.5 min Peak Depth= 0.51' Capacity at bank full= 11.50 cfs Inlet Invert= 195.10', Outlet Invert= 194.60' 18.0" Diameter Pipe n=0.012 Length= 49.0' Slope= 0.0102 '/' Reach 22R: 18" HDPE FROM DMH #5 TO DMH#6 Hydrograph Plot 3 0 a 1 -1 — 4- -- I. s i R t i 7 a 7 i +'P+'�1"`7 I. A A n ` V 1 O a IV 11 >z 13 14 15 16 17 18 19 20 Time (hours) Inflow Outflow 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 191 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 25R: 12" HDPE FROM CB#5 TO DMH#3 Inflow = 0.86 cfs @ 12.16 hrs, Volume= 0.069 of Outflow = 0.86 cfs @ 12.16 hrs, Volume= 0.069 af, Atten= 0 %, Lag= 0.1 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.0 fps, Min. Travel Time= 0.0 min Avg. Velocity = 1.8 fps, Avg. Travel Time= 0.1 min Peak Depth= 0.32' Capacity at bank full= 3.86 cfs Inlet Invert= 202.02', Outlet Invert= 201.92' 12.0" Diameter Pipe n=0.012 Length= 10.0' Slope= 0.0100 '/' Reach 25R: 12" HDPE FROM CB#5 TO DMH#3 Hydrograph Plot — Inflow — Outflow r.. H w V 3 0 LL v i c s 4 o ti 1 S 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) 60 -155 ROCKRIDGE POST — F Type 111 24 -hr Rainfall =5.40" Prepared by Coler & Colantonio, Inc. Page 193 HydroCAD® 6.00 s/n 001012 ©1986 -2001 Applied Microcomputer Systems 3/4/2003 Reach 28R: 12" HDPE FROM CB#7 TO DMH #5 Inflow = 0.66 cfs @ 12.07 hrs, Volume= 0.045 of Outflow = 0.65 cfs @ 12.08 hrs, Volume= 0.045 af, Atten= I%, Lag= 0.4 min Routing by Stor- Ind +Trans method, Time Span= 0.00 -20.00 hrs, dt= 0.05 hrs Max. Velocity= 4.2 fps, Min. Travel Time= 0.2 min Avg. Velocity = 1.5 fps, Avg. Travel Time= 0.6 min Peak Depth= 0.25' Capacity at bank full= 4.71 cfs Inlet Invert= 197.23', Outlet Invert= 196.50' 12.0" Diameter Pipe n=0.012 Length= 49.0' Slope= 0.0149/' Reach 28R: 12" HDPE FROM CB#7 TO DMH #5 Hydrograph Plot Inflow — Outflow v 3 0 U. c 4 b 1 U 9 10 11 12 13 14 15 16 17 18 19 20 Time (hours) STORM DRAINAGE ANALYSIS AND DESIGN for the proposed improvements to "Rockridge at Laurel Park' on 25 Coles Meadow Road Northampton, Massachusetts 010160 Prepared For: New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 Project No. 60- 155.00 [*Tj ' F�-0 3 Prepared by Coler & Colantonio, Inc. 1 Sugarloaf Street South Deerfield, MA 01373 Tel: (413) 665 -5300 Fax: (413) 665 -5390 March 5, 2003 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 STORM DRAINAGE ANALYSIS AND DESIGN for the proposed improvements to "Rockridge at Laurel Park" 25 Coles Meadow Road in Northampton, Massachusetts 1.0 INTRODUCTION Coler & Colantonio, Inc. has prepared this drainage analysis and design for the proposed improvements to the "Rockridge at Laurel Park" assisted living facility in Northampton, Massachusetts. The property is shown on Assessor's Map 13, Lot 073 and is owned and operated by New England Deaconess Association of Concord, Massachusetts. The existing 11.09 acre site is located at the intersection of Coles Meadow Road and L- North King Street, adjacent to the Massachusetts State Police barracks. The property is bounded on the North and West by land of the Laurel Park Association, on the East by North King Street, and on the South by Coles Meadow Road (refer to project locus in Appendix I). The project proposes the expansion and redevelopment of the Rockridge assisted living facility with improvements to the access drive, parking, sidewalks, utilities, landscaping, and a closed- conveyance drainage system with underground stormwater detention system. The proposed expansion includes construction of a three -story building and twelve one cottages with carports. The improvments will add 19 congregate assited living units and 12 attached elderly housing cottages to the existing site for a grand total of approximately 88 units. The existing main access drive has been lengthened and terminates in a cul -de -sac near the new entrance. A new driveway across from the existing parking area has been proposed to access the one - bedroom cottages and terminates in an emergency hammer -head style turnaround. New parking areas have been added for visitors and staff near the main entrance and service entrances. Independent water and sewer connections have been proposed from Coles Meadow Road to serve the new facility. The property is located in the suburban residential district (SR) within the planned village overlay. The surrounding areas along North King Street support a variety of mixed residential and commercial uses. The proposed site is previously developed and consists of an existing three - story/one -story combination building with gross floor area of approximately 38,800 sf (14,500 sf + in plan area) and a parking lot for 44 vehicles. There are two existing access points to the site; one on North King Street used for deliveries and staff, the other off of Coles Meadow Road is the main entrance and includes visitor - parking areas. A gravel access drive extends from the main entrance to Laurel Park and serves primarily as a secondary access to that facility. Topographic relief across the existing site is on the order of 32 feet. The site is nearly level near North King Street and climbs moderately from the main entrance to the western property line near Coles Meadow Road. The northeastern portion of the site contains two separate narrow bands of bordering vegetated wetlands separated by small New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 ridge. The tributary drainage area is approximately 14.91 acres and encompasses the land between the property line and Coles Meadow Road to the West. The purpose of this report is to compare the existing drainage conditions with the proposed conditions relative to the down gradient runoff generated by proposed improvements. Stormwater management will be provided according to policy established by the Massachusetts Department of Environmental Protection "Stormwater Management" Volumes 1 and 2 issued March 1997 and the current City of Northampton Site Plan approval regulations. The proposed facility provides a conservative approach to the development of the site through a careful design that will match or provide less impact as compared to the pre - development conditions. The project has been designed to mitigate for impacts to the 2 -year, 10 -year, and 25 -year storm events. The 100 -year storm event has been evaluated against adverse impact to downstream properties and will not substantially increase off -site flooding impacts. The closed- conveyance drainage system has been designed with deep sump catch basins, water quality inlets, smooth - walled HDPE, and Corrugates Steel Pipe (CSP) to collect and direct the surface water from the newly developed and existing impervious areas to a series of corrugated steel pipe underground storage tanks. Existing stormwater controls have been retrofitted and upgraded to the extent practicable and feature a Stormceptor® water quality inlet to treat the runoff from the service parking area. The existing 44 car parking area has been rerouted into the new conveyance system for treatment of suspended solids and detention prior to controlled release. The stormwater management system has been designed to minimize the volume, rate of discharge, control erosion and sedimentation, provide for recharge of groundwater, and reduce the runoff characteristics for the 2 -year, 10 -year, and 25 -year storm events. The proposed improvements are shown on the plans entitled "Proposed Site Improvements, Rockridge at Laurel Park, Coles Meadow Road and North King Street, Northampton, Massachusetts'; dated March 6, 2003 as prepared by Coler & Colantonio, Inc., 1 Sugarloaf Street, South Deerfield, MA 01373. 1.1 METHODOLOGY HydroCAD Stormwater Modeling System computer program by Applied Microcomputer Systems was used to develop stormwater runoff rates and volumes for the existing and proposed conditions at the project site. The software uses Soil Conservation Service (SCS) methodology. The SCS method is based on rainfall observations that were used to develop the Intensity- Duration - Frequency relationship or IDF curve. By studying the Weather Bureau's Rainfall Frequency Atlases, the SCS determined that four "mass curves" could be used to represent the characteristics of the rainfall distribution throughout the country. The mass curve is a dimensionless distribution of rainfall over time, which indicates the fraction of the rainfall event that occurs at a given time within a 24 -hour precipitation event. This synthetic distribution develops peak rates for storms of varying durations and intensities. The SCS distribution provides a cumulative rainfall at any point in time and allows volume dependent routing runoff calculations to occur. -- The HydroCAD software is a hydrograph generation and routing program similar to TR -20. Both programs utilize the SCS methodology. The HydroCAD software has the New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 additional capability to describe shallow concentrated flow. The "NEH -4 Upland Method" included in the HydroCAD software is applicable for conditions which occur in the headwaters of a watershed up to 2000 acres. The NEH -4 Upland Method allows the Time of Concentration (T,) to reflect ground conditions such as overland flow, grassed waterways, paved areas and upland gullies. The T is the time required for water to flow from the most distant point on a runoff area to the measurement or collection point. This results in a model that more accurately reflects the ground surface for shallow concentrated flow conditions, than TR -20 which is limited to distinguishing only paved and unpaved surfaces. In instances where the watersheds are small and impervious, Tc has been directly entered as a 5- minute minimum. This is consistent with the Rational Method, TR -55 Urban Hydrology for Small Watersheds, and standard engineering practice. The lower boundary of 5 minutes will yield a conservative, yet practical measure of stormwater runoff flow. 1.2 SOIL MORPHOLOGY Soils are grouped according to their potential runoff characteristics. Soils are assigned to four groups, A through D. Group A contains soils with high infiltration rates when thoroughly wet and have low runoff potential. This group includes mainly sands and gravels consisting of deep, well to excessively drained media (sand, loamy sand or sandy loam). Group D, at the other end of the spectrum, has slow infiltration rates and high runoff potential. High water table, clay layers, and nearly impervious material are all characteristics associated with this group. A USDA Soil Conservation Service map can be found in the appendix indicating soils present on the project site according to the Soil Survey of Hampshire County Massachusetts, Central Part, December 1981. Soils throughout the site were classified into the following soil groups: Soil Group/ Symbol Hydrologic Group Hinckley loamy sands (HgA) A Charlton sandy foams -Rock Outcrop Hollis complex (CrC) 8 The Soil Conservation Service (SCS) defines Hinckley loamy sands as deep and excessively drained. The soils are formed in glacial outwash deposits and are commonly found on outwash plains, kames, and terraces. Typical profiles of these soils indicate a very dark grayish brown loamy sand about 8 inches thick, and a 21 -inch subsoil consisting of brown loamy and gravelly sand. The substratum extends to a depth of 60 inches or more and is classified as a loose brownish yellow stratified sand, coarse sand, gravelly sand, and gravel. Permeability of these soils is rapid in the subsoil and very rapid in the substratum. These soils are well suited to cultivated crops, hay, pasture, and on -site absorption systems. Hinckley soils are commonly found on level to gently sloping areas on `— the sides of hills, ridges, and small drainage ways. Approximately 40% of the total tributary drainage area or 5.96 acres± consists of the Hinckley series. The Charlton series consists of deep, well- drained soils on uplands formed in glacial till. This soil is commonly found on hills and the side slopes of small drainage ways. New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 A typical profile of Charlton soil is contained beneath wooded areas with a surface layer of about 7 inches containing dark fine sandy loam, a 15 inch thick subsoil of yellowish- brown, fine sandy loam and /or light -olive brown gravelly fine sandy loam, and an olive colored substratum that extends from a depth of 60 inches or more containing a massive, firm, gravelly sandy loam. Permeability of Charlton soil is moderately rapid in the subsoil and substratum. These soils are well- suited to trees and most areas are wooded. Slope is the main limitation of these soils for small commercial buildings and absorption fields. The remaining 60% of the tributary drainage area or approximately 8.95 acres+ is Charlton soils. 1.3 DESIGN CRITERIA This drainage analysis was developed utilizing a Type III, 24 -hour storm as developed by the Soil Conservation Service. Two distinct design points were chosen at down gradient points in the drainage area to compare development conditions for each of the following storm frequencies. The design storm frequencies and corresponding rainfall depths were compiled from the "Atlas of Precipitation Extremes for the Northeastern United States and Southeastern Canada" and Technical Paper No. 40, Rainfall Frequency Atlas of the United States for Durations from 30 Minutes to 24 Hours and 1 to 100 Years" and have been estimated as follows: Storm Frequency (Years) 100 25 10 2 1.4 EXISTING CONDITIONS Rainfall Depth (Inc 7.3 5.4 4.4 3.0 The project site consists of an existing three -story building with one -story addition and parking facilities for approximately 44 vehicles. All of the existing developments are confined to the southern end of the site along Coles Meadow Road and North King Street. The grounds around the facility consist of light woods and grassed areas. The remaining land to the North and East of the existing buildings is wooded uplands. The site is bisected by a bordering vegetated wetland and depression to the North of the existing facility. It was determined through site visits, aerial photography, and soil surveys that the majority of the site is woods, lawn, and woods /lawn mix in good condition. The tributary drainage area has a weighted average CN value of 57. The attached Existing Drainage Plan in Appendix C delineates the watersheds for the project and has been divided into two distinct design points for runoff comparison. Design Point 1 is the area tributary to the 24" Box Culvert that passes under Route 5810 (North King Street) and eventually travels into the Interstate 91 drainage system. Design Point 2 is the area tributary to the 30" twin culverts to the extreme North of the site. This design point remains unchanged in the post drain condition as no improvements are proposed within this watershed. A limited stormwater conveyance system is contained 4 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 onsite and routes two catch basins from the main parking area under the building to the northeast side where roof drains from the existing facility and a catch basin in the service parking area terminate into an 12" RCP outfall. The outfall travels to an area upstream of Design Point#1. There appears to be no existing infiltration or water quality BMP's utilized in the current layout. The 100 -year storm was routed through the existing facility for illustrative purposes only. The *HydroCAD model confirms that this limited system cannot handle the expected flows from this storm event. * (see summary Section 1.7) 1.5 PROPOSED CONDITIONS The Applicant proposes to construct a three -story addition to the existing facility including twelve one - bedroom cottages with a new building footprint area of approximately 0.67 acres. The associated site improvements include driveways, parking facilites, site utilities, ADA compliant walkways, landscaping, and a state -of- the -art underground stormwater management facility utilizing innovative treatment technologies. The existing `- entrance drive will be enlarged and extended to provide access to the new addition. A new internal driveway will stem from the existing access drive to provide vehicular entry to the cottages. Additional parking, including private parking areas and carports for the cottages will be incorporated into the site design to provide parking areas for approximately 90 total vehicles. Pedestrian access will be achieved through a system of lighted asphalt walks and features a wooded park and formal garden area. The service area entrance will be �. reconfigured and enlarged to provide parking spaces for staff including relocation of a storage building from the south side of the facility. A boardwalk and footpath will be constructed to provide access across the bordering wetland, making the existing community garden site accessible to the residents of the assisted - living facility. Impervious pavement areas will increase by approximately 1.1 acres have reduced calculated open space from 89% to 71%. The attached Proposed Drainage Plan contains the subcatchments for each tributary watershed. The weighted average CN value for the tributary watershed has increased to 63. The closed- conveyance stormwater management system consists of smooth - walled high- density polyethylene (HDPE) and corrugated steel drain pipe (CSP) connected between a series of precast manholes and deep sump hooded catch basins. The proposed underground detention facility is fabricated from perforated 60" diameter aluminized type 2 corrugated steel pipe (CSP) with 3"x1" corrugations (12 ga.) to provide the required detention volume. The underground stormwater management facility is backfilled with %" angular crushed stone and wrapped with an engineered non -woven filter fabric to provide additional storage area and to facilitate infiltration into the surrounding soils. 36" diameter CSP connects the facility to a 30" diameter riser outlet structure contained within a 72" diameter manhole to control release rates of various design storms. The proposed stormwater management detention structure outlets to a level spreader to dissapate energy and control erosion. The existing 12" metal pipe /RCP drainage system and outlet will continue to convey roof runoff from the existing three -story building. To guard against possible impacts from the proposed, erosion and sedimentation control measures will be incorporated into the sequence of construction. This will include both modified construction procedures and temporary construction installations to control the movement of sediment into protected areas. Upon completion of all work, restoration and stabilization of disturbed areas will commence. Erosion /sedimentation control 5 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 installations include placement of hay bales and filter- fabric fencing around disturbed areas and at storm drainage inlet points. On -going stabilization of disturbed areas will be completed as the work progresses. Restoration/stabilization measures include seeding, mulching, and placement of stabilization fabric where required. These controls will be removed once a good vegetative cover is established and is accepted by the Northampton Conservation Commission. The proposed drainage improvements have been designed to meet the City of Northampton site plan approval requirements as well as the Massachusetts Department of Environmental Protection's Stormwater Management Policy. The stormwater conveyance and detention system has been designed to mitigate the increases in the peak rates of runoff from the site for the 2 -year, 10 -year, and 25 -year 24 -hour design storm events. The 100 -year design storm has been evaluated for the site and exceeds the flow of the pre development condition *, but does not appear to affect downstream properties. 1.6 SUMMARY OF RESULTS AND CALCULATIONS The stormwater management for the proposed project includes: stormwater collection, treatment, and infiltration systems. These proposed mitigation measures were designed in accordance with the Massachusetts Department of Environmental Protection " Stormwater Management Volume 1 & 2, the Vortech® stormwater system, and the Stormceptor® system. In accordance with these regulations and standard engineering practice, the potential impacts of this project on downstream properties are mitigated and summarized in the tables below. The following is a summary of the calculation results for runoff encompassing the areas tributary to the Rockridge at Laurel Park improvements for the 2 -year, 10 -year, 25- year, and 100 -year design storm events. Detailed routing and volume calculations can be found in various sections appended to this narrative. Existing 7 Conditions Summary Design Point 1 - 24" Box Culvert *Design Point 2120 - Twin 30" Culverts _ .,. 2 . .. .,... , ..,. ,,n 3.0 2.16 0.356 0.01 0.003 10- r 4.4 8.33 0.950 0.19 0.040 25- r 5.4 13.30 1.493 0.61 0.089 100-yr 7.3 # 22.65 # 2.726 2.41 0.220 L New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 Proposed Conditions Summary Design Point 10 - 24" Box Culvert ** ** MITIGATED 2- r 3.0 6.94 0.724 1.90 0.403 10- r 4.4 14.57 1.477 7.00 1.082 25- r 5.4 21.47 2.116 11.97 1.688 100- r 7.3 36.70 3.486 34.09 3.005 Notes: * Design Point #2 is identical to Design Point #20. No improvements are proposed in the area tributary to this point, therefore no comparison between existing and proposed is warranted. ** Mitigated runoff rates and volumes as shown include the benefit of BMP's, Detention, and Infiltration Measures. # The 100 -year storm values as shown are for illustrative purposes only. The HydroCAD model for the existing storm drainage condition indicates that the current system cannot handle this storm event. The tables above indicate that peak rates have remained consistent or decreased between post- drainage and pre- drainage conditions when summed at the design points down gradient of the site. The new stormwater system conveyances will not discharge untreated runoff into any resource or buffer areas and have been designed to infiltrate into the surrounding soils through partial exfiltration in the underground stormwater management system. A presumed increase in runoff is shown for the 100 -year post condition at Design Point 10. The 100 -year storm is conveyed through a 30" horizontal orifice emergency outfall emptying into the wetland upstream of the 24" square box culvert. The existing 12" RCP outfall has been retained to convey clean roof runoff from the existing three -story building to the wetland. The groundwater recharge volume for this site has been calculated based upon " type A and type B hydrologic soils. The overall tributary drainage area consists of a 60 -40 split for group B and A soils respectively. Only 5% of the proposed impervious area covers Type A soil. The recharge calculations have been adjusted to reflect a decrease in required volume to compensate for existing impervious areas. The adjusted recharge volume is calculated by reducing the total required recharge volume by the existing required volume to total 0.037 acre -feet or 1,600 cf. Groundwater recharge is achieved through partial exhitration in the underground stormwater management system below the outlet structure and in the stone and perforated pipe infiltration trench near the main 7 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 entrance. The 2ft x 3ft x145 ft long infiltration trench has been incorporated into the design to help convey snowmelt and runoff from Subcatchment 26. This area was removed from Subcatchment 3 to help reduce the burden of the existing drainage system and to increase the "dead storage" available for recharge. A total of approximately 1,600 cf of "dead storage" is available for infiltration in these BMP's prior to any release. It is important to note that these BMP's will continue recharge to groundwater as flow rates increase above outlet inverts. The post- drainage conditions will not reduce groundwater recharge as compared to the existing site and should improve as much of the existing impervious areas have been directed towards the detention facility for partial infiltration. A long -term infiltration rate of 2.2 inches per hour or 0.003 feet per minute was estimated using the USDA soil classification of gravelly sandy loam and loamy sands presumed in the detention area. This infiltration rate is consistent with the rapid permeability in the substratum as listed in the USDA Soil Survey Engineering Properties and concurs with published permeability rates for Charlton (CrC) and Hinckley (HgA) soils ranging from 0.6 to 20 inches /hour. The depth to groundwater and long -term infiltration rate will be confirmed through exploratory borings scheduled in for building and foundation design. Treatment of stormwater runoff volume equal to 0.5" of rainfall over the proposed impervious areas tributary to the drainage area has been provided by the stormwater management system for the purpose of meeting water quality standards. An increase of 1.76 acres ± of impervious area is proposed in the current layout (3.24a total - 1.48a existing = 1.76a). The total impervious area of 1.76 acres produces the required total volume of 0.073 acre -feet. A separate storm drainage conveyance system has been designed to covey approximately 0.67 acres (29,000 sf ±) of new clean roof runoff to the detention system for partial exfiltration. The actual volume to be treated has been reduced to 0.045 acre -feet or 1,960 cubic feet by factoring in the reduction of roof top runoff volume (1.76a - 0.67a =1.09a x 0.5" depth or 1,960 cf) because it is separated and conveyed separately to the stormwater management facility. The required water quality volume has been met through innovative technology by incorporating Stormceptor ® and VortechsTM treatment systems. These water quality inlets incorporate baffles, weirs, and hydrodynamic forces to enhance gravitational separation of floating and settling materials from stormwater flows without conventional sediment traps. The Stormceptor® has been sized based upon proprietary software which calculates sediment removal efficiency based upon particle size distribution. The VortechsTM' system has been specified as an off -line system that diverts low flows to the unit for treatment. Each system has a high flow by -pass to safely convey large, low probability storm events. The proposed stormwater management system has been designed to provide in excess of the required "calculated" 80% removal of Total Suspended Solids (TSS) tributary to the conveyance system on the proposed site per the Massachusetts D.E.P. Stormwater Management Policy. Discretionary street sweeping, deep sump catch basins, inlet Stormceptor® and off -line Vortechs® systems have been utilized in the design to remove an average of 87% of the Total Suspended Solids (TSS) from the tributary site runoff. The performance of the Vortech® and Stormceptor® systems have been verified by the Massachusetts Envirotechnology Partnership (STEP) and are approved for wide spread use. The effect of the underground detention facility was not factored into the calculations because the removal of accumulated sediment is more difficult than a conventional at- grade system. New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 The existing asphalt parking and service areas were retrofitted and routed through water quality inlets and detention facilities to further reduce impact from the site. A chart illustrating each proposed conveyance to the detention facility is provided in the supplemental calculations. The supporting calculations indicate that the proposed facilities are more than sufficient to mitigate the effects of the development on stormwater runoff quality entering the resource areas. 1.7 STORMWATER MANAGEMENT STANDARDS The following is an explanation on how the proposed project meets the Stormwater Management Standards as prepared by the MA Department of Environmental Protection and the MA Office of Coastal Zone Management. Please refer to the Stormwater Management Form in Appendix B. Untreated Stormwater (Standard 1) - No new stormwater system conveyances will discharge untreated runoff into the resource or buffer areas or cause erosion in the onsite wetlands. A closed- conveyance drainage system has been designed to direct stormwater runoff from the newly developed areas to Stormceptor® and VortechsTm water quality inlets for pre- treatment prior to partial exfiltration of first flush runoff through the underground stormwater management system. A riprap outlet spreader will dissipate runoff energy from significant storm events before release into a wetland resource area. The wetland will transmit the clean runoff to the 24" Box Culvert eventually traveling into the Interstate 91 drainage system. Post - Development Peak Discharge Rates (Standard 2) — The peak discharge rates were calculated with the aid of a hydrograph routing program using TR -20 methodology. A multi -stage outlet structure has been sized to meet the run -off rates for the 2 -yr, 10 -yr and 25 -yr storm events and reduce the volume of runoff over unmitigated levels. The stormwater detention system will partially detain the 100 -year storm event to provide a buffer against off -site flooding impacts. A 30" diameter emergency overflow orifice has been incorporated into the outlet structure to convey the 100 -yr storm event. Exfiltration will occur in the underground stormwater management system after pre- treatment through deep sump catch basins and water quality inlets. Recharge to Groundwater (Standard 3) - The majority (95 %) of the impervious areas for the tributary drainage area are contained within Hydrologic Grouping B as shown on the drainage area maps. Recharge to groundwater will be provided through partial exfiltration in the underground stormwater management system and through a 145 -foot long infiltration trench. An exfiltration rate of 2.2 inch /hour (0.003 feet/minute) is utilized in the calculations and is consistent with sandy loam /loamy sand soils mapped onsite. The proposed development and expansion will not reduce groundwater recharge as compared to the existing site and will approximate current conditions to the extent feasible. Supplemental drainage calculations found in the appendix. Removal of 80% TSS (Standard 4) - The proposed stormwater management system has been designed to provide the required "calculated" removal of the Total Suspended Solids (TSS) for the conveyance system on the proposed site per the Massachusetts D.E.P. Stormwater Management Policy. Discretionary street sweeping, deep sump hooded catch 9 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 basins, innovative water quality inlets, and a partial exfiltration detention facility has been utilized in the design to remove an average of at least 80% of the Total Suspended Solids (TSS) from the total site storm runoff. Large portions of the existing impervious parking and service areas have been captured and treated by the proposed system to provide an increase in treatment for the redeveloped portions of the site. A chart illustrating each proposed conveyance outfall is provided in the supplemental calculations. Land Uses with Higher Pollutant Loads (Standard 5) — The property is zoned suburban residential (SR) district within the planned village overlay. The proposed use as an assisted living facility is not considered a land use with high pollutant loads. Critical Areas (Standard 6) — The project is not located within a critical area as defined the Stormwater Management Policy. For the purposes of this design, an equivalent Water Quality Volume of 0.5" x new impervious area was maintained and treated through innovative technologies to preserve and protect the Bordering Vegetated Wetland resource areas and buffer zones. Redevelopment (Standard 7) — The project proposes a combination of redevelopment and new development on the site. The associated improvements have been designed with BMP's to the extent practicable to meet the performance standards in the Stormwater Management Policy including retrofitting and expanding the existing system to meet TSS removal, water quality, and mitigation of peak discharge rates. Erosion and Sediment Controls (Standard 8) — Staked hay bales and filter- fabric fencing will be used during construction as outlined in the Operation & Maintenance Plan and shown on the plan set. Direction of silt -laden runoff shall be directed towards vegetated areas, temporary sedimentation basins, and diversion swales. Operation and Maintenance Plan (Standard 9) — An Operation and Maintenance plan has been customized to fit the design of the proposed Rockridge site improvements. Provisions to maintain runoff control devices have been assured through structural, non- structural, and construction management approaches. Please see the attached O &M Plan. 1.8 CONCLUSION In conclusion, the results of this report indicate that the proposed stormwater management plan appears to meet all requirements of the City of Northampton and the Massachusetts Department of Environmental Protection's " Stormwater Management Policy" within the scope and parameters of the proposed project. 10 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 STORMWATER OPERATION AND MAINTENANCE PLAN OWNER AND RESPONSIBLE PARTY: Construction Phase Activities: New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 Contact: Mr. Walter Bartkus, Director of Engineering Services Phone: (978) 369 -5151 Day -to -day Operation and Maintenance: Rockridge at Laurel Park 25 Coles Meadow Road Northampton, Massachusetts 01060 Contact: Mr. Walter Jones Phone: (413) 586 -2902 PROJECT OVERVIEW The proposed project includes construction of a three -story addition (37,500 sf gross floor area) to the existing facility plus 12 one - bedroom cottages and associated site improvements including parking facilites, paved access drives, utilities, landscaping, ADA compliant walkways, and a closed- conveyance stormwater management system. CONSTRUCTION MANAGEMENT A construction manager with adequate knowledge and experience on projects of similar size and scope shall be employed to oversee all sitework related construction. During construction, silt -laden runoff or discharge from dewatering operations (if necessary) will be prevented from entering wetlands and resource areas untreated. Siltation barriers consisting of a filter fabric silt fence, hay bales will be erected in advance of construction along the downstream edge of all disturbed areas and maintained throughout the construction period. Check dams will be used in temporary constructed drainage ways as necessary to reduce erosion. If dewatering is required during the construction, discharges may be directed toward vegetated areas for settlement of suspended solids. Outflow of silt -laden runoff shall not be permitted to flow directly into the wetlands or resource areas. Upon completion of site stabilization, the catch basins and existing conveyance system 11 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 shall be thoroughly cleaned of silt and sediment and made ready for the proposed operation. Siltation barriers, temporary settling basins, and diversion berms shall be constructed and inspected by the resident project Engineer on a monthly basis or as necessary, after any significant (0.5" or more) storm event and daily while dewatering operations are proceeding. Care should be taken when constructing stormwater control structures. Light earth - moving equipment shall be used to excavate in the vicinity of the infiltration areas. Use of heavy- equipment causes excessive compaction of the soils beneath the basin resulting in reduced infiltration capacity. At no time shall temporary infiltration areas or settling basins be constructed in the vicinity of the proposed infiltration system in order to prevent the soils from becoming clogged with sediment. NON - STRUCTURAL APPROACHES PARKING LOT /DRIVEWAY SWEEPING The property owner shall maintain a program of parking lot/driveway sweeping to reduce sediment accumulation in the deep sump catch basins. It is recommended that sweeping occur at least once in the fall and spring prior to cleaning and inspection of the catch basin and manhole structures. GRADING The impervious areas of the site shall be graded as gently as possible, generally not more than 4% or 5% slopes to reduce runoff velocities. Steep slopes will be permanently vegetated to dissipate energy and reduce potential erosion. No constructed vegetated slopes should exceed 2H:1 V. Steep slopes may require soil reinforcement and additional vegetation. FLOW OVER VEGETATED AREAS Wherever possible, runoff from paved areas and snowmelt shall be directed over vegetated areas to promote settlement of suspended solids before entering a wetland or resource area. STRUCTURAL BEST MANAGEMENT PRACTICES DEEP SUMP CATCH BASINS, AREA DRAINS, AND MANHOLE STRUCTURES Catch basins shall be cleaned, in dry weather, when half of the sump capacity is filled or at a minimum of twice a year. Cleaning will take place at the completion of construction, in early spring after sanding of roadways has ceased, and in the fall. All manholes shall be inspected at least once annually. Any obstructions, sediment, and debris that could potentially cause clogs shall be removed within the 12 New England Deaconess Association 80 Deaconess Road Concord, Massachusetts 01742 conveyance system as necessary. Inverts, grates, and hoods shall be checked and replaced as necessary to maintain hydraulic effectiveness. DETENTION FACILITY WITH PARTIAL EXFILTRATION The underground detention system has been designed with riser structures at grade to aid the removal of sediment and debris accumulating in the structure. The detention facility contains a multi -stage outlet structure to meet individual storm events. Once the system goes online, inspections should occur after each storm event for the first few months to ensure proper stabilization, function, and to ensure that the outlets remain free of obstructions. Preventative maintenance shall be performed at least twice per year and after every major storm event (> 1" of rainfall) and shall include removal of accumulated sediment, inspection of the detention structure, and monitoring of groundwater and infiltration rates to ensure proper operation of the system. Important items to check for include differential settlement, cracking, breakout, clogging of outlets and vents, and root infestation. Water levels should be checked and recorded against rainfall amounts to verify that the drainage system is working properly. ENERGY DISSAPATORS AND LEVEL SPREADERS During the construction phases of the project, the energy dissipaters and level spreaders that receive significant runoff shall be inspected monthly and cleaned as necessary and /or after major storms events (> 1" of rainfall). Thereafter, these structures will be cleaned at least twice per year, in the spring and fall, or as needed depending on the frequency of major storm events (> 1" of rainfall). The riprap shall be inspected, cleaned of sediment and debris, and reinstalled as necessary to maintain effectiveness. GRASS -LINED SWALES Swales shall be inspected on a semi - annual basis in the early spring and fall. Additional inspections shall be performed during the first few months after construction to ensure that adequate vegetation has been established. Regular maintenance shall include mowing, fertilizing, pruning, debris removal, and weed /pest control. Swales shall be mowed at least once per year to a minimum of 4 inches so as not to reduce the effectiveness of pollutant removal and energy dissipation. Accumulated sediment and debris shall be manually removed at least twice per year. WATER QUALITY INLETS Water quality inlets shall be inspected and cleaned in accordance with the manufacturer's recommendations. Documentation from the manufacturer is attached. 13