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00 Attachment A - Long-Term O&M Plan_2020-04-22                                                    CDS® Inspection and Maintenance Guide ENGINEERED SOLUTIONS Maintenance The CDS 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. For example, unstable soils or heavy winter sanding will cause the grit chamber to fill more quickly but regular sweeping of paved surfaces will slow accumulation. Inspection Inspection is the key to effective maintenance and is easily performed. Pollutant transport and deposition may vary from year to year and regular inspections will help ensure that the system is cleaned out at the appropriate time. At a minimum, inspections should be performed twice per year (e.g. spring and fall) however more frequent inspections may be necessary in climates where winter sanding operations may lead to rapid accumulations, or in equipment washdown areas. Installations should also be inspected more frequently where excessive amounts of trash are expected. The visual inspection should ascertain that the system components are in working order and that there are no blockages or obstructions in the inlet and separation screen. The inspection should also quantify the accumulation of hydrocarbons, trash, and sediment in the system. Measuring pollutant accumulation can be done with a calibrated dipstick, tape measure or other measuring instrument. If absorbent material is used for enhanced removal of hydrocarbons, the level of discoloration of the sorbent material should also be identified during inspection. It is useful and often required as part of an operating permit to keep a record of each inspection. A simple form for doing so is provided. Access to the CDS unit is typically achieved through two manhole access covers. One opening allows for inspection and cleanout of the separation chamber (cylinder and screen) and isolated sump. The other allows for inspection and cleanout of sediment captured and retained outside the screen. For deep units, a single manhole access point would allows both sump cleanout and access outside the screen. The CDS system should be cleaned when the level of sediment has reached 75% of capacity in the isolated sump or when an appreciable level of hydrocarbons and trash has accumulated. If absorbent material is used, it should be replaced when significant discoloration has occurred. Performance will not be impacted until 100% of the sump capacity is exceeded however it is recommended that the system be cleaned prior to that for easier removal of sediment. The level of sediment is easily determined by measuring from finished grade down to the top of the sediment pile. To avoid underestimating the level of sediment in the chamber, the measuring device must be lowered to the top of the sediment pile carefully. Particles at the top of the pile typically offer less resistance to the end of the rod than consolidated particles toward the bottom of the pile. Once this measurement is recorded, it should be compared to the as-built drawing for the unit to determine weather the height of the sediment pile off the bottom of the sump floor exceeds 75% of the total height of isolated sump. Cleaning Cleaning of a CDS systems should be done during dry weather conditions when no flow is entering the system. The use of a vacuum truck is generally the most effective and convenient method of removing pollutants from the system. Simply remove the manhole covers and insert the vacuum hose into the sump. The system should be completely drained down and the sump fully evacuated of sediment. The area outside the screen should also be cleaned out if pollutant build-up exists in this area. In installations where the risk of petroleum spills is small, liquid contaminants may not accumulate as quickly as sediment. However, the system should be cleaned out immediately in the event of 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 absorbent pads since they are usually less expensive to dispose than the oil/water emulsion that may be created by vacuuming the oily layer. Trash and debris can be netted out to separate it from the other pollutants. The screen should be power washed to ensure it is free of trash and debris. Manhole covers should be securely seated following cleaning activities to prevent leakage of runoff into the system from above and also to ensure that proper safety precautions have been followed. Confined space entry procedures need to be followed if physical access is required. Disposal of all material removed from the CDS system should be done in accordance with local regulations. In many jurisdictions, disposal of the sediments may be handled in the same manner as the disposal of sediments removed from catch basins or deep sump manholes. CDS Diameter Distance from Water Surface Sediment Model to Top of Sediment Pile Storage Capacity ft m ft m yd3 m3 CDS2015-4 4 1.2 3.0 0.9 0.9 0.7 CDS2015 5 1.5 3.0 0.9 1.3 1.0 CDS2020 5 1.5 3.5 1.1 1.3 1.0 CDS2025 5 1.5 4.0 1.2 1.3 1.0 CDS3020 6 1.8 4.0 1.2 2.1 1.6 CDS3030 6 1.8 4.6 1.4 2.1 1.6 CDS3035 6 1.8 5.0 1.5 2.1 1.6 CDS4030 8 2.4 4.6 1.4 5.6 4.3 CDS4040 8 2.4 5.7 1.7 5.6 4.3 CDS4045 8 2.4 6.2 1.9 5.6 4.3 CDS5640 10 3.0 6.3 1.9 8.7 6.7 CDS5653 10 3.0 7.7 2.3 8.7 6.7 CDS5668 10 3.0 9.3 2.8 8.7 6.7 CDS5678 10 3.0 10.3 3.1 8.7 6.7 Table 1: CDS Maintenance Indicators and Sediment Storage Capacities 800.925.5240www.ContechES.com Support• Drawings and specifications are available at www.contechstormwater.com. • Site-specific design support is available from our engineers. ©2014 Contech Engineered Solutions LLC Contech Engineered Solutions LLC provides site solutions for the civil engineering industry. Contech’s portfolio includes bridges, drainage, sanitary sewer, stormwater, earth stabilization and wastewater treament products. For information, visit www.ContechES.com or call 800.338.1122 NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS AN EXPRESSED WARRANTY OR AN IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. SEE THE CONTECH STANDARD CONDITION OF SALES (VIEWABLE AT WWW.CONTECHES.COM/COS) FOR MORE INFORMATION. The product(s) described may be protected by one or more of the following US patents: 5,322,629; 5,624,576; 5,707,527; 5,759,415; 5,788,848; 5,985,157; 6,027,639; 6,350,374; 6,406,218; 6,641,720; 6,511,595; 6,649,048; 6,991,114; 6,998,038; 7,186,058; 7,296,692; 7,297,266; 7,517,450 related foreign patents or other patents pending. cdsMaintenance 11/14 ENGINEERED SOLUTIONS CDS Inspection & Maintenance Log CDS Model: Location: Water Floatable Describe Maintenance Date depth to Layer Maintenance Personnel Comments sediment 1 Thickness 2 Performed —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— —————————————————————————————————————————————————————————— 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. If the difference between these measurements is less than the values listed in table 1 the system should be cleaned out. Note: to avoid underestimating the volume of sediment in the chamber, the measuring device must be carefully lowered to the top of the sediment pile. 2. For optimum performance, the system should be cleaned out when the floating hydrocarbon layer accumulates to an appreciable thickness. In the event of an oil spill, the system should be cleaned immediately. Project: Responsible Party: Address: Date: BPM Name:Page: 1 of 3 Operation & Maintenance Inspection Checklist BMP Element:Potential Problem:Pass Fail Recommended Remediation Bituminous Concrete Roadway Build-up of sediment over the winter months and collection of leaves during the fall months. Deep-Sump Catch Basins Sediment has accumulated to a depth greater than the original design depth for sediment storage, approximately 2-feet of sediment. Stormwater Piping Blockage of inlet/outlet pipes due to debris or sediment accumulation. Downspout connections have been damaged or disconnected. Roof leaders are surcharging at the downspout connections CDS Water Quality Units Sediment has accumulated to a depth greater that the original design depth for sediment storage. Inspector's Signature Date Resolution: Sweep roadway using a high-efficiency street sweeper. Remove the sediment and dispose of in accordance with local and state regulations. Remove any debris and sediment via proper means. Dispose of debris/sediment in accordance with local & state regulations. Open and insepct at cleanout locations and remove any blockages. Roof Leaders Repair and reconnect downspout connections. Remove sediment and disposed of in accordance with local and state regulations. Project: Responsible Party: Address: Date: BPM Name:Page: 2 of 3 Operation & Maintenance Inspection Checklist BMP Element:Potential Problem:Pass Fail Recommended Remediation Excessive sediment accumulation. Erosion is occuring on the side slope or around the flared end section. Debris has collected inside the basin. Sediment has accumulated to 6" or above. Standing water inside basin. Erosion is occuring on the side slope or around the flared end section. Trees/Shrubs are starting to grow within the basin. Debris has collected inside the basin. Vegetation has started to grow within the riprap area. Accumulation of sediment/debris at the culvert inlet. Erosion is occuring where riprap has been dislodged. Inspector's Signature Date Sediment Forebay Remove sediment and debris. Remedy scoured area and/or replace riprap immediately. Remove debris and remedy any damage Remove the sediment and restablish the sediment forebay with vegetaion to the original bottom elevation Detention Basin Remedy scoured area and replace vegetation. Remove trees/shrubs and vegetate with grass. Flared End Sections Remove vegetation immediately. Remedy scoured area and replace riprap immediately. Remove sediment or debris such that the culvert has free flow. Resolution: Verify that sediment is not entering the basin. Remove collected sediment and scour basin bottom. Replace damaged vegetation Remove debris and remedy any damage caused. Project: Responsible Party: Address: Date: BPM Name:Page: 3 of 3 Operation & Maintenance Inspection Checklist BMP Element:Potential Problem:Pass Fail Recommended Remediation Sediment has accumulated over mulched surface. Erosion has occurred at inlets. Areas are devoid of mulch. Litter and/or debris has accumulated in bio-retention area. Vegetation has died or is distressed. Sediment has accumulated in riprap channel void space. Down-gradient gullies have formed due to sheet flow concentration. Inspector's Signature Date Level Spreader Remove the sediment and dispose of in accordance with local and state regulations and replace riprap. Fill gullies with native backfill, No. 6 pea-stone, topsoil and errosion control blanket. Sod or re-seed with stabalized errosion control grass mix. Bio-Retention Area Remove sediment and mulch mixture and replace mulch. Repair any eroded areas and replace with appropriate materials. Replace mulch as necessary. Remove litter and/or debris. Replace vegetation as necessary. Resolution: LOVEFIELDSTREETEASTHAMPTON ROAD - RTE 10 SCALE: DATE: JOB NO.:ph: 413.568.0985 fax: 413.568.0986 rlaland.com40 School Street · P.O. Box 640 · Westfield, MA 01086R LEVESQUE ASSOCIATES, INCA Land Planning Services CompanyBMP Location PlanProposed Self-Storage FacilityEasthampton RoadNorthampton, MassachusettsPlatinum Self Storage2100 Main Street, Suite 106Irvine, California180614 4/20/20 As Noted O&M