The URL can be used to link to this page

5. Revised CT River Interim Geotech Memo-3-3-21-complete An Equal Opportunity Employer M/F/V/H M E M O R A N D U M To: David Veleta, P.E. (Northampton, DPW) Kris Baker, P.E. (Northampton, DPW) From: Matthew A. Taylor, P.E. (GZA) Christopher Baker, P.E. (GZA) Yixing Yuan, Ph.D. (GZA) John G. DeLano, P.E. (GZA) Date: March 3, 2021 File No.: 01.0174343.00 Re: Interim Geotechnical Analyses Memorandum Engineering Services for Levee Certification Connecticut River Levee System Northampton, Massachusetts GZA GeoEnvironmental (GZA) is pleased to present this memorandum to the City of Northampton Department of Public Works (DPW), summarizing our interim geotechnical analyses efforts for the Connecticut (CT) River Levee System. A similar memorandum summarizing the interim geotechnical analyses for the Mill River Levee System will be provided under separate cover. This work was conducted in accordance with Task 4 of our agreement (WF7-19-2019) dated July 19, 2019, and is subject to the Limitations provided in Appendix A. GZA has completed subsurface exploration program for CT River Levee system between December 12, 2019 and January 14, 2020 and collected the necessary data to support the geotechnical (i.e. seepage, slope stability, wall stability, and settlement) analyses for the system. The subsurface exploration program and the associated data-collection works were summarized in our Geotechnical Data Memorandum for the System dated December 23, 2020. The engineering analyses presented in this memorandum are conducted to support the levee system certification and eventual Federal Emergency Management Agency (FEMA) accreditation in under Regulation 44 CFR 65.10. The interim geotechnical analyses completed to date utilized the currently available hydrologic and hydraulic (H&H) information for the CT River Levee System. The river levels for 100-year flood and normal conditions were obtained from 1978 Flood Insurance Rate Maps (FIRMs) and converted from NGVD29 to NAVD88 by using the USGS datum conversion tool. However, in 2020, FEMA began to update the H&H model for the Connecticut River, which may result in different 100-year flood elevations (i.e. Base Flood Elevations). FEMA’s updated H&H model will reportedly be available in 2021/2022. GZA will update the geotechnical analyses for the system once the updated H&H model is made available. March 3, 2021 File No. 01.0174343.00 Interim Geotechnical Analyses Memo – CT River Levee System Page | 2 Proactive by Design BACKGROUND CONNECTICUT RIVER LEVEE SYSTEM In response to significant flooding events in the 1920’s and 1930’s, the United States Army Corps of Engineers (USACE) designed and constructed flood control works along the Connecticut River to protect the City of Northampton (City), Hampshire County, Massachusetts. The Work was authorized under the Flood Control Act, approved on June 22, 1936, and construction along the Connecticut river was conducted over a series of contracts between December 1938 and June 1942. In 1944, the City accepted responsibility to operate and maintain the Connecticut River Levee System (System) in accordance with the Flood Control Regulations. Refer to Figure 1 for a Locus Map of the System. Refer to Appendix B for relevant System Record Drawings obtained from the 1945 Operations and Maintenance (O&M) Manual. The System protects the eastern part of the City against high water from the Connecticut River and includes 4,580 linear feet of earthen embankment levee, with a maximum height of 23 feet. The System begins near the intersection at Pomeroy Terrace and Hancock Streets and heads southeasterly across Ventures Field Road, Hockanum Road, the Old Mill River, the Boston & Maine Railroad Tracks, and U.S. Highway No.5, terminating approximately 500 feet west of U.S. Highway No. 5. The Northampton Flood Control Pumping station is located at the southern portion of the levee system and is surrounded by a total of 174 feet of concrete cantilevered floodwall, with a maximum height of 29 feet. Two stop-log closure structures are located along the levee system, one at the Boston & Maine Railroad Tracks, and the other at the U.S. Highway No. 5 crossing. SCOPE OF WORK GZA’s Scope of Work for the Connecticut River Levee System – Task 4 – Engineering Analyses and Evaluations includes levee embankment seepage and stability (Task 4.1), levee embankment settlement (Task 4.2), structural stability/adequacy of floodwalls (Task 4.3), and interior flooding of areas protected by the levee system (Task 4.4). This memo summarizes the portion of the scope of work completed to date for Tasks 4.1, which includes the subsurface data interpretation, analysis cross section selection, and interim seepage and slope stability analysis and results. The specific scope of work highlighted herein includes the following: 1. Develop subsurface cross-sections and profile at the specified locations for the proposed geotechnical analyses, based on the information derived from the existing explorations and GZA’s recent exploration program. 2. Develop the soil parameters to be used in the geotechnical analyses based on correlations with the in-situ exploration results and laboratory data collected from the subsurface exploration program. 3. Perform seepage analyses to evaluate the location of phreatic surface and pore pressures within and below the levee embankment, along with the exit gradient on the landside of the levee embankment sections under normal condition, flood condition, and rapid drawdown conditions. These initial seepage analyses conservatively assumed non-functional toe drains along certain sections of levee. 4. Perform slope stability analyses to evaluate the factor of safety for the critical slip surface in the levee embankment cross-sections under different loading conditions, including normal condition, flood condition, rapid drawdown, and seismic (pseudostatic) loading. 5. Prepare the interim geotechnical analysis memorandum to summarize our initial findings. March 3, 2021 File No. 01.0174343.00 Interim Geotechnical Analyses Memo – CT River Levee System Page | 3 Proactive by Design LEVEE EMBANKMENT CROSS-SECTION AND PROFILE DEVELOPMENT GZA developed levee embankment cross-sections and subsurface profiles to perform the required geotechnical analyses at the specified locations near Stations 3+00, 7+00, 10+00, 20+00 and 47+00 in the CT River Levee Embankment. Refer to Figure 2 for the locations of the analysis cross sections. The analysis sections were selected primarily based on the location of USACE typical design sections (1939 Plate II, Embankment Details), with the considerations of the boring locations proposed in our agreement (WF7-19-2019) dated July 19, 2019. These sections were selected to represent the variations in the embankment design details, the topography, and the subsurface soil profile along the CT River levee. The geometry and stratigraphy for each section profiles were initially generated by using Leapfrog Works (ver. 3.1.1), a 3D geological modeling software developed by SEEQUENT company. Using Leapfrog, GZA created a 3D geological model for CT River Levee, as shown in Appendix C, by integrating a Digital Elevation Model (DEM) for the current topography (USGS 2015 1), the longitudinal subsurface profile of the System as shown on Plate VIIIA of the 1945 O&M Manual, and new subsurface information obtained from the 2019/2020 subsurface exploration program conducted by GZA. GZA then extracted a soil profile cut along the levee axis in the model near Station 3+00, 7+00, 10+00, 20+00 and 47+00, as illustrated in Appendix C. The extracted subsurface profile was imported into the Geostudio Suite (v2019 R2) developed by SEEQUENT to establish the model cross-sections and stratigraphy for the proposed seepage and slope stability analyses at Stations 3+00, 7+00, 10+00, 20+00 and 47+00, as included in Appendix D. The elevations in these cross-sections are referenced to the North American Vertical Datum of 1988 (NAVD88). SOIL PARAMETER DEVELOPMENT GZA developed the soil parameters for the seepage and stability analyses based on correlations with the in-situ exploration results and laboratory data collected from previous and 2019/2020 subsurface exploration programs, as listed in Table 1. Refer to GZA’s Geotechnical Data Memorandum dated December 23, 2020 for previous test boring data, 2019/2020 test boring logs and 2020 geotechnical laboratory test results. The saturated hydraulic conductivity (permeability) values used in the seepage analyses, listed in Table 1, were estimated from grain-size correlations2,3,4,5 and published values for similar materials. The saturated unit weights and the total strength values for all the materials were estimated based on published typical values for similar materials, and GZA’s engineering experience. The effective strengths for the cohesionless fill materials were estimated based on empirical correlations with the SPT-N values obtained from 2019/2020 borings. The undrained strength profile for the Varved Clay layer was estimated based on published values in the studies on Connecticut Valley Varved Clay (CVVC)6,7. The summary of the effective strengths estimated for the cohesionless soils and the referenced strength values for the CVVC layer is included in Appendix D. 1 USGS Lidar DEM: Maine & Massachusetts 2015 QL1 & QL2 Lidar dataset, https://www.fisheries.noaa.gov/inport/item/49407 2 Slichter, Charles S. 1905, Field measurements of the rate of movement of underground waters, U. S. Geological Survey Water Supply Paper 140: 106 pp 3 Sherard, J.L., Dunnigan, L.P., and Talbot, J.R., 1984, Basic Properties of Sand and Gravel Filters. ASCE Journal of Geotechnical Engineering, v.110 #6, June 1984, p.684-700 4 Hazen, A. (1911) Discussion: Dams on Sand Foundations Trans. ASCE, vol. 73 p.199 5 Terzaghi, Peck, & Mesri, Soil Mechanics in Engineering Practice, 3rd Ed, 1996 6 DeGroot, D.J. & Lutenegger A.J. (2002) Geology and Engineering Properties of Connecticut Valley Varved Clay, International Workshop on Characterization and Engineering Properties of Natural Soils, Singapore, December 2002 7 Ladd, C.C., and Wissa, A.E.Z, (1970) Geology and Engineering Properties of Connecticut Valley Varved Clays with Special Reference to Embankment Construction, MIT Research Report R70-56, Department of Civil Engineering, Massachusetts Institute of Technology, September 1970, p154. March 3, 2021 File No. 01.0174343.00 Interim Geotechnical Analyses Memo – CT River Levee System Page | 4 Proactive by Design Table 1. Material Parameters used in GZA’s Seepage and Stability Analyses Strata Total Unit Weight, γt (pcf) Effective Strength Parameters Total Strength Parameters Saturated Horizontal Hydraulic conductivity, ksat Cohesion c' (psf) Friction Angle φ'(°) Cohesion (psf) Friction Angle, φ(°) ft/s cm/s Topsoil Fill 120 0 31 100 10 4.2E-07 1.3E-05 Existing Fill 120 0 30 Same as effective strength 4.3E-04 1.3E-02 Impervious Blanket Fill 120 0 32 200 10 4.2E-07 1.3E-05 Pervious Fill 120 0 32 Same as effective strength 1.6E-04 4.8E-03 Random Fill 125 0 34 500 11 1.5E-06 4.6E-05 Riprap 145 0 40 Same as effective strength 1.0E-01 3.0E+00 Existing Embankment* 110 0 28 300 10 5.9E-08 1.8E-06 Silt & Clay** 110 0 28 300 10 2.9E-08 8.9E-07 Sand 120 0 30 Same as effective strength 3.5E-04 1.1E-02 Varved Clay (CVVC) 110 su increases with depth*** su = 500psf 2.0E-07 6.1E-06 * Existing embankment corresponds to the Existing Organic Fill encountered beneath Random Fill in test borings CT-13 and CT-14. ** Silt & Clay represents the Sand and Silt, Silt and Clay, and Silt layers encountered beneath Random Fill in the test borings. ***The su strength profile used in the stability analyses is included in the attachment of Appendix D SEEPAGE ANALYSES GZA performed steady-state seepage analyses for selected cross-sections of the CT River Levee Embankment under normal and flood conditions using Seep/W, a two-dimensional finite element seepage analysis software included in the GeoStudio Suite. The analyses allow estimation of the location of the phreatic surface through the embankment, the pore pressures, and the exit gradients at specific finite element nodes at the landside toe of the embankment. The material parameters used in the steady seepage and stability analyses are listed in Table 1. The river levels for 100-year flood and normal conditions at the selected cross-sections were obtained from the 1978 Flood Insurance Rate Maps (FIRMs), which were based on a Flood Insurance Study in 1976 (Appendix B). FEMA is currently updating the hydrologic and hydraulic model for the Connecticut River and will be issuing an updated Flood Insurance Study in the next few years. As such, revised 100-year flood elevation (i.e. Base Flood Elevations) will be generated. At that time, an update of the seepage and associated stability calculations for the flood case will be required. The landside water level for each of the selected cross sections was conservatively assumed to be at the landside ground surface under normal conditions. Based on existing exploration data shown on record drawing (Appendix B), the landside groundwater levels are typically below the ground surface. The impacts of the landside groundwater levels will be re-visited in conjunction with a sensitivity evaluation of the functionality of the toe drain and its impact on the calculated factors of safety during a later phase of the analyses. Although the CT River Levee was constructed with a toe drain on the landside, based on the record drawings in Appendix B, previous toe drain functionality and effectiveness evaluation have been inconclusive. As such, GZA conservatively ignored the effects of the toe drains for the interim steady state seepage analyses described herein. For the flood case, the seepage model was used to predict the location of the phreatic surface within the levee March 3, 2021 File No. 01.0174343.00 Interim Geotechnical Analyses Memo – CT River Levee System Page | 5 Proactive by Design embankment starting from the landside ground surface, assuming a non-functioning toe drain, as the initial starting point. Appendix E summarizes the graphic results of the steady-state seepage analyses for CT River levee for the specified sections under normal and flood level conditions. The calculated seepage gradients at the landside toe of the levee under the analyzed river conditions do not appear to exceed the critical gradient as required by the US Army Corps. Of Engineers (USACE) 8, as shown in Table 2, below. Table 2. Water Levels and Calculated Exit Gradients for Seepage Analyses River Elevation Critical Gradient* Exit Gradients Station 3+00 7+00 10+00 20+00 47+00 100-yr Flood 0.5 <0.1** <0.1 <0.1 0.3 0.29 Normal Conditions 0.5 <0.1 <0.1 <0.1 <0.1 <0.1 * The critical gradient required by US Army Corps. Of Engineers (USACE) 8 ** Negligible seepage gradients calculated at landside toe are indicated as <0.1 SLOPE STABILITY ANALYSES GZA performed slope stability analyses for the riverside and landside slopes of the CT River Levee embankments and calculated a factor of safety against slope instability under various loading conditions. The slope stability models were created using SLOPE/W, a two-dimensional limit equilibrium slope stability modeling software included in the GeoStudio Suite. Factors of safety against slope instability were estimated by the Spencer Method as implemented by SLOPE/W. Porewater pressures developed from the previously described steady state seepage analyses were directly input by the software into the slope stability analyses, so that the models were able to consider seepage forces and phreatic surfaces. The material parameters used in the slope stability analyses are listed in Table 1. The stability of the riverside slope of the levee embankment under “rapid drawdown” from flood conditions to the normal level of the CT River was performed using the USACE three-stage method as implemented by SLOPE/W. The slope stability under seismic loading was also evaluated using a pseudo static approach under normal conditions. Based on USACE guidance 9, GZA used 2/3’s of a regionally developed peak ground acceleration (PGA) value by USGS 10, with a return period of 2,475 years as the input for the pseudo static seismic analysis. The resulting acceleration used in the analyses was 0.12g. The graphical output for the Slope/W stability analyses, including the critical failure slip surfaces and their associated factors of safety are presented in Appendix E. The factors of safety for the riverside and landside slopes were calculated under the loading conditions listed in Table 3, below. The calculated factors of safety met or exceed the minimum required values per the USACE guidance 11, with the exceptions of the landside slope of Station 47+00 under the 100-year flood condition. 8 USACE EM1110-2-1901, "Seepage Analysis and Control for Dams" 9 USACE EM1110-2-6053, “Earthquake Design and Evaluation of Concrete Hydraulic Structures”, Appendix B 10 USGS Seismic Design Maps webtool, https://earthquake.usgs.gov/ws/designmaps 11 USACE EM1110-2-1902, “Slope stability” March 3, 2021 File No. 01.0174343.00 Interim Geotechnical Analyses Memo – CT River Levee System Page | 6 Proactive by Design Table 3. Slope Stability Analysis Results for Connecticut River Levee Loading Condition Levee Face Factor of Safety Minimum Required* Station 3+00 7+00 10+00 20+00 47+00 100-year Flood (Steady State) Landside 1.4 1.5 1.6 1.9 1.5 1.3 Riverside 1.6 2.0 2.1 2.2 1.5 Sudden Drawdown - 100- year Flood Riverside 1.0 - 1.2 1.3 1.5 1.6 1.4 1.3 Normal Conditions Landside 1.4 1.6 1.8 1.9 1.7 1.4 Riverside 1.6 1.9 2.0 1.8 1.6 Seismic (Pseudostatic) Normal Conditions Landside 1.0* 1.2 1.1 1.2 1.1 1.1 Riverside 1.2 1.2 1.2 1.1 1.2 * Required factors of safety are based on USACE guidelines except for seismic case, where a minimum factor of safety greater than 1.0 is typically used in dam engineering practice. CONCLUSIONS GZA offers the following conclusions: • Interim Steady seepage analyses results indicate that the CT River Levee Embankment adequately meet the criteria against piping under normal conditions and 100-yr flood conditions even with conservative landside water levels and toe drain assumptions. • The interim slope stability analyses results suggest that almost all of the CT River Levee meets the required factor of safety for slope stability of the riverside and landside slopes under loading conditions specified in EM 1110-2-1902, with the exception of the Section near Sta. 47+00. The landside slope of Section 47+00 yielded a marginally low factor of safety under the 100-yr flood condition. • The slope stability factors of safety in some areas of the levee, particularly under seismic loading, are highly dependent on the strength of the underlying, thick, CVVC deposit. Higher seismic loads, or lower in-situ strengths within the CVVC deposit, could result in unacceptable factors of safety. RECOMMENDATIONS GZA offer the following recommendations: • A sensitivity analysis should be performed to determine if a functional toe drain at STA. 47+00 would result in a calculated factors-of-safety against landslide slope instability meeting the USACE requirements. If the analysis results suggest that a functional toe drain can effectively improve the slope stability, GZA would likely recommend confirming the working status of the toe drains. • Additional review of the subsurface information collected during the 2019/2020 subsurface exploration program should be performed to identify samples for additional laboratory testing including strength testing, index testing, and consolidation testing. The results of which should be used to refine the soil March 3, 2021 File No. 01.0174343.00 Interim Geotechnical Analyses Memo – CT River Levee System Page | 7 Proactive by Design parameters used in the final seepage and stability analyses as well as the subsequent levee embankment settlement analyses (Task 4.2) and wall stability analyses (Task 4.3). • GZA recommends performing laboratory tests on the varved clay samples to refine the estimate of the undrained shear strength profile. Given that these soils have been subjected to over 60 years of consolidation under the levee embankments, an increase in strength over time would be expected. o This is particularly important for the pseudostatic analyses, which are marginally acceptable and could potentially fall below the required values if a larger acceleration or lower clay strength is considered. • If the laboratory strength tests are unable to provide a refined estimate of the varved clay strength (either due to sample disturbance or inability to capture in-situ stress and/or porewater conditions) seismic cone penetration test (SCPT) testing in areas of the CT river levee where thick deposits of varved clay were encountered may allow for site-specific strengths to be better understood. o Additionally, the SCPT probes would allow for a better understanding of how the CVVC deposits respond to seismic forces. REMAINING TASKS TO BE COMPLETED In accordance with our agreement (WF7-19-2019) dated July 19, 2019, GZA has the following tasks to be completed: • Task 4.1 – Levee Embankment Seepage and Stability Analysis – Finalize the analyses after FEMA issues the updated H&H data for the Connecticut River System. • Task 4.2 Levee Embankment Settlement Analysis – Complete the analysis for one (1) representative cross section of the CT River Levee System. The analysis should be performed after consolidation testing has been completed; and • Task 4.3 Evaluation of the Floodwall Stability for one (1) cross section for the CT River Levee System – The analysis should be performed in a similar manner as the levee embankment seepage and stability analyses (i.e. interim and then final once the H&H data has been issued). • The interim geotechnical analysis memorandum will be updated with the final results of Task 4.1 to 4.3. CLOSING We trust that the information contained in this memorandum meets the City’s needs at this time. Please feel free to contact us if you have any questions or comments regarding the content of this memorandum. Figures Figure 1 – Locus Plan Figure 2 – Analysis Cross Section Location Plan Appendices: Appendix A – Limitations Appendix B – Record Drawings and Existing Flood Level Information March 3, 2021 File No. 01.0174343.00 Interim Geotechnical Analyses Memo – CT River Levee System Page | 8 Proactive by Design Appendix C – 3D Leapfrog Model Screenshots Appendix D – Model Parameters Appendix E – Output for Seepage and Slope Stability Analyses Proactive by Design FIGURES PROJ. MGR.: CLB DESIGNED BY: YY REVIEWED BY: CLB OPERATOR: YY DATE: 8-26-2019 JOB NO. 401,000 2,000500 SCALE IN FEETUSGS QUADRANGLE LOCATION © 2020 - GZA GeoEnvironmental, Inc., J:\170,000-179,999\174343\174343-00.CLB\Memos\Stability\CT Levee Appendix\Figures\Figure 1 - LOCUS PLAN - Northampton-12-29-2020.mxd, 12/29/2020, 2:54:48 PM, Yixing.yuanCONNECTICUT RIVER & MILL RIVER LEVEENORTHAMPTON, MASSACHUSETTS FIGURE NO. 01.174343.00 1 SOURCE: THIS MAP CONTAINS THE BING MAPS AERIAL ONLINE MAP SERVICE. LOCUS PLAN Legend E Station Floodwall Levee A GZA_Boring PROJ. MGR.: CLB DESIGNED BY: YY REVIEWED BY: CLB OPERATOR: YY DATE: 8-26-2019 JOB NO. 401,000 2,000500 SCALE IN FEETUSGS QUADRANGLE LOCATION © 2020 - GZA GeoEnvironmental, Inc., J:\170,000-179,999\174343\174343-00.CLB\Memos\Stability\CT Levee Appendix\Figures\Figure 2 -SECTION LOCATION -CT - Northampton-12-29-2020.mxd, 12/30/2020, 11:43:40 AM, Yixing.yuanCONNECTICUT RIVER LEVEENORTHAMPTON, MASSACHUSETTS FIGURE NO. 01.174343.00 2 SOURCE: THIS MAP CONTAINS THE BING MAPS AERIAL ONLINE MAP SERVICE. ANALYSES SECTION LOCATION Legend E Station Floodwall Levee CrossSection A GZA_Boring Proactive by Design APPENDIX A LIMITATIONS GEOTECHNICAL LIMITATIONS File No. 01.0174343.00 Page | 1 October 2020 Proactive by Design USE OF REPORT 1. GZA GeoEnvironmental, Inc. (GZA) prepared this report on behalf of, and for the exclusive use of our Client for the stated purpose(s) and location(s) identified in the Proposal for Services and/or Report. Use of this report, in whole or in part, at other locations, or for other purposes, may lead to inappropriate conclusions; and we do not accept any responsibility for the consequences of such use(s). Further, reliance by any party not expressly identified in the contract documents, for any use, without our prior written permission, shall be at that party’s sole risk, and without any liability to GZA. STANDARD OF CARE 2. GZA’s findings and conclusions are based on the work conducted as part of the Scope of Services set forth in Proposal for Services and/or Report, and reflect our professional judgment. These findings and conclusions must be considered not as scientific or engineering certainties, but rather as our professional opinions concerning the limited data gathered during the course of our work. If conditions other than those described in this report are found at the subject location(s), or the design has been altered in any way, GZA shall be so notified and afforded the opportunity to revise the report,as appropriate, to reflect the unanticipated changed conditions . 3. GZA’s services were performed using the degree of skill and care ordinarily exercised by qualified professionals performing the same type of services, at the same time, under similar conditions, at the same or a similar property. No warranty, expressed or implied, is made. 4. In conducting our work, GZA relied upon certain information made available by public agencies, Client and/or others. GZA did not attempt to independently verify the accuracy or completeness of that information. Inconsistencies in this information which we have noted, if any, are discussed in the Report. SUBSURFACE CONDITIONS 5. The generalized soil profile(s) provided in our Report are based on widely-spaced subsurface explorations and are intended only to convey trends in subsurface conditions. The boundaries between strata are approximate and idealized, and were based on our assessment of subsurface conditions. The composition of strata, and the transitions between strata, may be more variable and more complex than indicated. For more specific information on soil conditions at a specific location refer to the exploration logs. The nature and extent of variations between these explorations may not become evident until further exploration or construction. If variations or other latent conditions then become evident, it will be necessary to reevaluate the conclusions and recommendations of this report. 6. In preparing this report, GZA relied on certain information provided by the Client, state and local officials, and other parties referenced therein which were made available to GZANat the time of our evaluation. GZA did not attempt to independently verify the accuracy or completeness of all information reviewed or received during the course of this evaluation. 7. Water level readings have been made in test holes (as described in this Report) at the specified times and under the stated conditions. These data have been reviewed and interpretations have been made in this Report. Fluctuations in the level of the groundwater however occur due to temporal or spatial variations in areal recharge rates, soil heterogeneities, the presence of subsurface utilities, and/or natural or artificially induced perturbations. The water table encountered in the course of the work may differ from that indicated in the Report. 8. Recommendations for foundation drainage, waterproofing, and moisture control address the conventional geotechnical engineering aspects of seepage control. These recommendations may not preclude an environment that allows the infestation of mold or other biological pollutants. GEOTECHNICAL LIMITATIONS File No. 01.0174343.00 Page | 2 October 2020 Proactive by Design COMPLIANCE WITH CODES AND REGULATIONS 9. We used reasonable care in identifying and interpreting applicable codes and regulations. These codes and regulations are subject to various, and possibly contradictory, interpretations. Compliance with codes and regulations by other parties is beyond our control. COST ESTIMATES 10. Unless otherwise stated, our cost estimates are only for comparative and general planning purposes. These estimates may involve approximate quantity evaluations. Note that these quantity estimates are not intended to be sufficiently accurate to develop construction bids, or to predict the actual cost of work addressed in this Report. Further, since we have no control over either when the work will take place or the labor and material costs required to plan and execute the anticipated work, our cost estimates were made by relying on our experience, the experience of others, and other sources of readily available information. Actual costs may vary over time and could be significantly more, or less, than stated in the Report. SCREENING AND ANALYTICAL TESTING 11. We collected environmental samples at the locations identified in the Report. These samples were analyzed for the specific parameters identified in the report. Additional constituents, for which analyses were not conducted, may be present in soil, groundwater, surface water, sediment and/or air. Future Site activities and uses may result in a requirement for additional testing. 12. Our interpretation of field screening and laboratory data is presented in the Report. Unless otherwise noted, we relied upon the laboratory’s QA/QC program to validate these data. 13. Variations in the types and concentrations of contaminants observed at a given location or time may occur due to release mechanisms, disposal practices, changes in flow paths, and/or the influence of various physical, chemical, biological or radiological processes. Subsequently observed concentrations may be other than indicated in the Report. ADDITIONAL SERVICES 14. GZA recommends that we be retained to provide services during any future: site observations, design, implementation activities, construction and/or property development/redevelopment. This will allow us the opportunity to: i) observe conditions and compliance with our design concepts and opinions; ii) allow for changes in the event that conditions are other than anticipated; iii) provide modifications to our design; and iv) assess the consequences of changes in technologies and/or regulations. Proactive by Design APPENDIX B RECORD DRAWINGS and Existing Flood Level Information Proactive by Design APPENDIX C 3D LEAPFROG MODEL SCREENSHOTS Historic soil profile excerpts from 1945 O&M manual 3D digital elevation model for CT river levee Figure C1 -Leapfrog 3D model integrating subsurface information GZA borings CT-1 to CT14 Figure C2 -3D geological model created based on subsurface information 3D geological model for CT River levee Figure C3 -Soil profile for Cross-sections at specified locations Section near Sta.3+00 Section near Sta.7+00 Section near Sta.10+00 Section near Sta.20+00 Section near Sta.47+00 Proactive by Design APPENDIX D Model Parameters GZA Engineers and JOB GeoEnvironmental, Inc.Scientists SHEET NO.1 OF 249 Vanderbilt Avenue CALCULATED BY YY DATE Norwood, MA 02062 CHECKED BY JGD DATE 781‐278‐3700 SCALE FAX 781‐278‐5701 http://www.gza.com Objective:This cover sheet summarizes the soil hydraulic conductivity and strength parameters determined for seepage and slope stability analyses of Connecticut River (CT) Levee and Mill River (MR) Levee in Northampton, MA Method: ‐ Estimate hydraulic conductivity for granular soil samples from test boring using laboratory data (grain size & USCS classification) and typical values of similar materials. See the appended correlation spreadsheets for more details 1) "Correlation of SPT‐N Values to phi Worksheet ‐ Connecticut River Levee" 2) "Correlation of SPT‐N Values to phi Worksheet ‐ Mill River Levee" ‐ Estimate friction angle for granular soils from test borings and typical values of similar materials. See the appended correlation spreadsheets for more details 3) "Empirical Correlations for Hydraulic Conductivity ‐ Connecticut River Levee" 4) "Empirical Correlations for Hydraulic Conductivity ‐ Mill River Levee" ‐ Estimate parameters for the varved clay based on the published value in the literature Subsurface Profile: ‐ The sub‐surface profiles for CT Levee and MR Levee was developed by using the following information: 1) Boring log information from GZA Borings CT1 to CT14 on CT Levee and Boring logs from GZA Boring MR1 to MR8 on MR Levee 2) Record Drawing ”Northampton Dike ‐ Subsurface Profile ‐ Conn. River Dike ‐ Operation and Maintenance Manual“ by Corps. of Engineers, U.S. Army, Providence, RI, dated April 1945, Plates VIII A & XV A 3) Record Drawing ”Northampton Dike ‐ Embankment Details ‐ Conn. River Dike ‐ Operation and Maintenance Manual“ by Corps. of Engineers, U.S. Army, Providence, RI, dated April 1945, Plate VIII & XIII 4) Design Report "Connecticut River Flood Control Project‐ Northampton Mass Connecticut & Mill Rivers Analysis of Design for Local Protection Works ‐ Item No.2 & No.3 " by Corps of Engineers, US Army dated April 1939 ‐ The Seequent 3D geological modeling software ‐ Leapfrog was then used to model the topography and the soil strata for the cross‐sections at a series of selected locations along the levee. ‐ The developed profile for each section was imported into the Seequent Geostudio program for seepage and stability analyses ‐ Three representative sections (two for CT Levee and one for MR levee) and the associated soil layers are shown below as example. ‐ The material parameters determined for the soil layers identified in the sections below are summarized in Table 1. Fig.1 Section Sta. 10+00 of CT‐ Levee Fig.2 Section Sta. 47+00 of CT‐ Levee Fig.3 Section Sta. 20+00 of MR Levee 174343.00 Northampton Levee Certification Support 2 5/30/2020 6/1/2020 N/A Existing_Embank Top Soil Pervious Fill Impervious FillRandom_Fill Sand Varved_Clay Top Soil Pervious Fill Impervious Fill Existing_Fill Random_Fill Silt_and_Clay Sand Varved_Clay Existing_Fill Sand Varved_Clay Weathered_Sandstone riprap Impervious Fill Random_Fill Existing Fill Random_Fill Impervious Core Top Soil GZA Engineers and JOB GeoEnvironmental, Inc.Scientists SHEET NO.2 OF One Edgewater Drive CALCULATED BY YY DATE Norwood, MA 02062 CHECKED BY JGD DATE 781‐278‐3700 SCALE FAX 781‐278‐5701 http://www.gza.com Table 1. Summary of Material Properties: ft/s cm/s 120 0 31 100 10 1 4.2E‐07 1.3E‐05 120 0 30 1 4.3E‐04 1.3E‐02 120 0 32 200 10 1 4.2E‐07 1.3E‐05 120 0 32 1 1.6E‐04 4.8E‐03 125 0 34 500 11 1 1.5E‐06 4.6E‐05 145 0 40 1 1.0E‐01 3.0E+00 110 0 28 300 10 1 5.9E‐08 1.8E‐06 110 0 28 300 10 1 2.9E‐08 8.9E‐07 120 0 30 1 3.5E‐04 1.1E‐02 110 0.143 2.0E‐07 6.1E‐06 120 0 32 800 0 1 7.3E‐10 2.2E‐08 110 0.143 2.0E‐07 6.1E‐06 130 0 45 1000 0 1 7.8E‐09 2.4E‐07 Note (1) ‐ Unit weight values based on typical values for similar materials (2) ‐ Permeability values was estimated based grain size correlations and typical values for similar materials (3) ‐ Drained strength values based on correlations from SPT‐N testing and also typical values for similar materials (4) ‐ Undrained strength for Varved clay based on the lower bound of the range published by DeGroot & Lutenegger (2002). (5) ‐ Unit weight, Effective Strength, K‐ratio, and permeability values based on typical values published by DeGroot & Lutenegger (2002). Attachments: Attachment Excerpts of literature for material parameters of the varved clay same as effective strength same as effective strength Weathered Bedrock (1),(2),(3) Impervious Core Random Fill Sand (1),(2),(3) (4),(5) (1),(2),(3) Varved Clay (4),(5) Riprap su increases with depth su = 500psf Friction Angle, '(°) Same as in CT Levee Same as in CT Levee Strength (Drawdown) Riprap Existing Embankment Strata Random Fill Existing Fill same as effective strength same as effective strength 2 Mill River Levee Total Unit Weight, t (pcf) Strength Parameters Cohesion, c' (psf) Connecticut River Levee Top Soil Saturated Horizontal Hydraulic conductivity, ksat Notes Friction Angle, (°) 174343.00 Northampton Levee Certification Support 5/30/2020 6/1/2020 N/A Impervious Fill K Ratio (kv/kh) Impervious Fill Cohesion (psf) Pervious Fill Same as in CT Levee Same as in CT Levee Same as in CT Levee Sand Silt & Clay Same as in CT Levee su increases with depthVarved Clay su = 500psf Existing Fill Top Soil Attachment Excerpts of literature for material parameters of the varved clay Figure V1. Horizontal Hydraulic conductivity for varved clay (DeGroot & Lunenegger 2002) Selected kh=6E‐6cm/sec = 2E‐7ft/sec Figure V2. Undrained strength distribution for Varved clay suggested by Ladd and Wissa (1970) Figure V3. Table of undrained strength values for Varved clay suggested by Ladd and Wissa (1970) Selected undrained strength profile for Varved Clay CT Levee Elevation Depth [ft] su [ksf] 90 42 540 80 52 600 70 62 660 60 72 705 50 82 755 40 92 800 MR Levee Elevation Depth [ft] su [ksf] 108 32 480 98 42 540 88 52 600 20 30 40 50 60 70 80 90 100 400 500 600 700 800 900 Depth below levee crest [ft]Selected Undrained Strength su for Varved Clay [ksf] CT MR Proactive by Design APPENDIX E OUTPUT FOR SEEPAGE AND SLOPE STABILITY ANALYSES GZA GeoEnvironmental, Inc. 249 Vanderbilt Avenue JOB Norwood, MA 02062 SHEET NO.1 OF 781‐278‐3700 CALCULATED BY CJT/YY DATE FAX 781‐278‐5701 CHECKED BY JD DATE http://www.gza.com SCALE Objective:Evaluate seepage and slope stability of Northampton Connecticut River Levee at the following Cross‐Sections 3+00, 7+00, 10+00, 20+00, 47+00 Method: 1) Develop typical cross section of levee at selected Stations 3+00, 7+00, 10+00, 20+00, 47+00 2) Determine material parameters from test borings and typical values of similar materials. 3) Calculate location of phreatic surface within levee for different conditions, using SEEP/W. Calculate exit gradient to evaluate piping failure (where applicable). Case #1 ‐ Steady‐state seepage at 100‐yr Flood Case #2 Steady‐state seepage under normal condition 4) Using pore water data from SEEP/W, calculate factors of safety against slope failure for the following load cases defined by requirements of EM 1110‐2‐1913, Section 6‐7302. Steady‐state factors of safety calculated for both riverside and landside slopes using Spencer method. Rapid drawdown factor of safety calculated using USACE 3‐stage method. Case #3 (A,B) ‐ Steady‐state seepage at 100‐yr Flood Case #3 (C) ‐ Rapid Drawdown from 100 yr Flood (Riverside only) Case #4 (A,B) ‐ Steady‐state seepage under normal condition Case #5 (A,B) ‐ Seismic (pseudostatic, 0.12g horizontal acceleration) 5) The above load cases conservatively ignored the toe drain at the downstream face, whose current functionality was not verified. Subsurface Information: ‐ Test borings CT‐1 through CT‐14 and Exploration Location Plan by GZA (December 2018‐ January 2019) ‐ "Analysis of Design and Local Protection Works Fiscal Year 1939 Section, Item N.2 Contract ‐ STA. 0 to High Ground Over Railroad And Highway" War Dept., Corps. of Engineers, U.S. Army, U.S. Engineer Office, Providence, RI, dated April 1939 ‐ "Analysis of Design and Local Protection Works Item N.3 Diversion Canal, Oxbow Bridge and Dike Along East Bank Mill River Part Contract, Part Hired Labor" War Dept., Corps. of Engineers, U.S. Army, U.S. Engineer Office, Providence, RI, dated April 1939 ‐ "Operation and Maintenance Manuel for Flood Protection System Northampton, Massachusetts" War Dept., Corps. of Engineers U.S. Army, U.S. Engineer Office, Providence, RI, dated April 1945 Assumptions: ‐ 0.12g Horizontal acceleration for pseudostatic seismic analysis calculated as 2/3 of the PGA for a Site Class E, per USGS Seismic Hazard Maps. ‐ Soil strata interpreted from available test boring data and design drawings, actual configuration may vary. Material Properties: ft/s cm/s 120 0 31 100 10 1 4.2E‐07 1.3E‐05 120 0 30 1 4.3E‐04 1.3E‐02 120 0 32 200 10 1 4.2E‐07 1.3E‐05 120 0 32 1 1.6E‐04 4.8E‐03 125 0 34 500 11 1 1.5E‐06 4.6E‐05 145 0 40 1 1.0E‐01 3.0E+00 110 0 28 300 10 1 5.9E‐08 1.8E‐06 110 0 28 300 10 1 2.9E‐08 8.9E‐07 120 0 30 1 3.5E‐04 1.1E‐02 110 0.143 2.0E‐07 6.1E‐06 (1) ‐ Unit weight values based on typical values for similar materials (2) ‐ Permeability values based grain size correlations (3) ‐ Drained strength values based on correlations from SPT‐N testing, total strength values are estimated (4) ‐ Total (undrained) strength based on correlations from SPT‐N testing (5) ‐ Unit weight, Effective Strength, K‐ratio, and permeability values based on typical values for CVVC published by DeGroot & Lutenegger. (6) ‐ Permeability values based on results of Army Corps design analysis Analysis Results: 3+00 7+00 10+00 20+00 47+00 0.5 <0.1 <0.1 <0.1 0.3 0.29 Y 0.5 <0.1 <0.1 <0.1 <0.1 <0.1 Y ‐ Note: Factor of safety values less than recommended values are shown in italics (1) ‐ Exit gradient was estimated from results of SEEP/W analysis at landside toe of the levee, and was denoted "<0.1" when the value is negligible (2) ‐ Limiting gradient per requirements of US Army Corps Technical Letter ETL 1110‐2‐569 "DESIGN GUIDANCE FOR LEVEE UNDERSEEPAGE" Same as effective strength OK?Station 1 100yr Flood 2 Normal Pool 174343.00 Northampton Levee Certification Support N/A 2 12/10/2020 12/10/2020 (1),(2),(3) (1),(2),(3) SEEPAGE ANALYSIS RESULTS ‐ EXISTING CONDITIONS (1),(2),(3) (1),(2),(3) su = 500psf (1),(2),(3) Case Impervious Fill Sand Pervious Fill su increases with depth Top Soil River Elevation Limiting Gradient(2) Exit Gradient, ie(1) Varved Clay (4),(5) (1),(3),(6) (1),(2),(3) Friction Angle, '(°) Cohesion (psf) Friction Angle, (°) Saturated Horizontal Hydraulic conductivity, ksat Same as effective strength Same as effective strength Same as effective strength Silt & Clay Strength (Drawdown) K Ratio (kv/kh) Total Unit Weight, t (pcf) Strength Parameters Cohesion, c' (psf) Strata Random Fill Existing Fill Riprap xisting Embankmen Notes GZA GeoEnvironmental, Inc. 249 Vanderbilt Avenue JOB Norwood, MA 02062 SHEET NO.2 OF 781‐278‐3700 CALCULATED BY CJT/YY DATE FAX 781‐278‐5701 CHECKED BY JD DATE http://www.gza.com SCALE Analysis Results cont'd: 3+00 7+00 10+00 20+00 47+00 1.5 1.6 1.9 1.5 1.3 1.6 2.0 2.1 2.2 1.5 1.6 1.8 1.9 1.7 1.4 1.6 1.9 2.0 1.8 1.6 1.2 1.1 1.2 1.1 1.1 1.2 1.2 1.2 1.1 1.2 ‐ Note: Factor of safety values less than recommended values are shown in italics (1) ‐ FS = 1.0 applies to flood levels unlikely to persist for long periods prior to drawdown, FS = 1.2 applies to levels likely to persist for long periods prior to drawdown. (2) ‐ Earthquake loading applied as a lateral load using seismic coefficient of 0.12g (3) ‐ Factor of safety not provided in EM 1110‐2‐1913 ‐ Refer to Attached SLOPE/W slope stability analysis graphical results MinimumLevee FaceLoading ConditionLoad Case Station 100‐year Flood (Steady State) 5 (A,B)Seismic(2) (Pseudostatic, normal conditions) D/S 1.0(3) U/S 4 (A,B) Normal Conditions D/S 1.4U/S U/S 1.0 ‐ 1.2(1)1.3 D/S3 (A,B) 1.4U/S 1.5 1.63 (C) Sudden Drawdown ‐ 100‐year Flood 174343.00 Northampton Levee Certification Support N/A 1.4 1.3 2 12/10/2020 SLOPE STABILITY ANALYSIS RESULTS ‐ EXISTING CONDITIONS Factor of Safety 12/10/2020 Comments / Notes Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Color Name Sat Kx (ft/sec) Existing_Fill 0.00043 Impervious Fill Pervious Fill Random_Fill Sand 0.000352 Silt_and_Clay 2.9e-08 Top Soil Varved_Clay 2e-07 Landside Riverside 100 yr Flood Elevation = 124 ft 4.2e-07 4.2e-07 0.00016 1.5e-06 XY Gradient < 0.1 Groundwater Level = 121.5 ft Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 Seepage Analysis 100 year flood level 1-1 3+00 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Color Name Sat Kx (ft/sec) Existing_Fill 0.00043 Impervious Fill Pervious Fill Random_Fill Sand 0.000352 Silt_and_Clay 2.9e-08 Top Soil Varved_Clay 2e-07 Landside Riverside Groundwater Level = 113 ft Normal Condition Elevation = 113 ft 1.5e-06 0.00016 4.2e-07 4.2e-07 XY Gradient < 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 1-2 3+00 Seepage Analysis Normal Conditions 1.5 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Landside Riverside 100 yr Flood Elevation = 124' Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 121.5 ft Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 1-3A 3+00 Downstream slope stability 100 year flood water level 1.6 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Landside Riverside 100 yr Flood Elevation= 124 ft Su = 660psf (El.70) Su = 540psf (El.90) Groundwater Level = 121.5 ft Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 1-3B 3+00 Upstream slope stability 100 year flood level 1.3 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Color Name Model Unit Weight (pcf) Cohesion' (psf) Phi' (°) Cohesion R (psf) Phi R (°) Existing_Fill Mohr-Coulomb 120 0 30 1 29 Impervious Fill Mohr-Coulomb 120 0 32 200 10 Pervious Fill Mohr-Coulomb 120 0 32 1 31 Random_Fill Mohr-Coulomb 125 0 34 500 11 Sand Mohr-Coulomb 120 0 30 1 29 Silt_and_Clay Mohr-Coulomb 110 0 28 300 10 Top Soil Mohr-Coulomb 120 0 31 100 10 Varved_Clay Su500psf Mohr-Coulomb 110 500 0.1 505 0 Landside Riverside 100 yr Flood Elevation = 124 ft Normal Condition Elevation = 113 ft Groundwater Level = 121.5 ft Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 1-3C 3+00 Upstream slope stability Rapid Drawdown - 100 year flood level 1.6 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Landside Riverside Normal Condition Elevation = 113 ft Su = 660psf (El.70) Su = 540psf (El.90) Groundwater Level = 113 ft Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 1-4A 3+00 Downstream slope stability Normal Conditions 1.6 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Landside Riverside Su = 660psf (El.70) Su = 540psf (El.90) Normal Condition Elevation = 113 ft Groundwater Level = 113 ft Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 1-4B 3+00 Upstream slope stability Normal Conditions 1.2 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Landside Riverside Normal Condition Elevation = 113 ft Su = 540psf (El.90) Pseudostatic seismic load 0.12g Su = 660psf (El.70) Groundwater Level = 113 ft Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 1-5A 3+00 Downstream slope stability Seismic - Normal Conditions 1.2 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Landside Riverside Su = 540psf (El.90) Pseudostatic seismic load 0.12g Normal Condition Elevation = 113 ft Su = 660psf (El.70) Groundwater Level = 113 ft Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 1-5B 3+00 Upstream slope stability Seismic - Normal Conditions Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 100 yr Flood Elevation = 124 ft Riverside Landside Groundwater Level = 112 ft XY Gradient < 0.1 Color Name Sat Kx (ft/sec) Existing_Fill 0.00043 Impervious Fill Pervious Fill Random_Fill Sand 0.000352 Silt_and_Clay 2.9e-08 Top Soil Varved_Clay 2e-07 4.2e-07 0.00016 1.5e-06 4.2e-07 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 2-1 7+00 Seepage Analysis 100 year flood level Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Riverside Landside Normal Condition Elevation = 113 ftGroundwater Level = 112 ft XY Gradient < 0.1 Color Name Sat Kx (ft/sec) Existing_Fill 0.00043 Impervious Fill Pervious Fill Random_Fill Sand 0.000352 Silt_and_Clay 2.9e-08 Top Soil Varved_Clay 2e-07 4.2e-07 0.00016 1.5e-06 4.2e-07 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 2-2 7+00 Seepage Analysis Normal Conditions 1.6 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Riverside Landside 100 yr Flood Elevation = 124 ft Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 112 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 2-3A 7+00 Downstream slope stability 100 year flood water level 2.0 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Riverside Landside 100 yr Flood Elevation = 124 ft Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 112 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 2-3B 7+00 Upstream slope stability 100 year flood level 1.5 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Riverside Landside 100 yr Flood Elevation = 124 ft Su = 500psf Groundwater Level = 112 ft Normal Condition Elevation = 113 ft Color Name Model Unit Weight (pcf) Cohesion' (psf) Phi' (°) Cohesion R (psf) Phi R (°) Existing_Fill Mohr-Coulomb 120 0 30 1 29 Impervious Fill Mohr-Coulomb 120 0 32 200 10 Pervious Fill Mohr-Coulomb 120 0 32 1 31 Random_Fill Mohr-Coulomb 125 0 34 500 11 Sand Mohr-Coulomb 120 0 30 1 29 Silt_and_Clay Mohr-Coulomb 110 0 28 300 10 Top Soil Mohr-Coulomb 120 0 31 100 10 Varved_Clay Su500psf Mohr-Coulomb 110 500 0.1 505 0 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 2-3C 7+00 Upstream slope stability Rapid Drawdown - 100 year flood level 1.8 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Riverside Landside Normal Condition Elevation = 113 ft Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 112 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 2-4A 7+00 Downstream slope stability Normal Conditions 1.9 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Riverside Landside Normal Condition Elevation = 113 ft Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 112 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 2-4B 7+00 Upstream slope stability Normal Conditions 1.1 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Riverside Landside Normal Condition Elevation = 113 ft Pseudostatic seismic load 0.12g Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 112 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 2-5A 7+00 Downstream slope stability Seismic - Normal Conditions 1.2 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Riverside Landside Normal Condition Elevation = 113 ft Pseudostatic seismic load 0.12g Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 112 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 2-5B 7+00 Upstream slope stability Seismic - Normal Conditions Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Landside Riverside 100 yr Flood Elevation = 124 ftGroundwater Level = 114 ft 4.2e-07 0.00016 1.5e-06 XY Gradient < 0.1 Color Name Sat Kx (ft/sec) Existing_Fill 0.00043 Impervious Fill Pervious Fill Random_Fill Sand 0.000352 Silt_and_Clay 2.9e-08 Top Soil Varved_Clay 2e-07 4.2e-07 0.00016 1.5e-06 4.2e-07 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 3-1 10+00 Seepage Analysis 100 year flood level Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Landside Riverside Normal Condition Elevation = 114 ft Groundwater Level = 114 ft 4.2e-07 0.00016 1.5e-06 XY Gradient < 0.1 Color Name Sat Kx (ft/sec) Existing_Fill 0.00043 Impervious Fill Pervious Fill Random_Fill Sand 0.000352 Silt_and_Clay 2.9e-08 Top Soil Varved_Clay 2e-07 4.2e-07 0.00016 1.5e-06 4.2e-07 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 3-2 10+00 Seepage Analysis Normal Conditions 1.9 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Landside Riverside 100 yr Flood Elevation = 124 ft Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 114 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 3-3A 10+00 Downstream slope stability 100 year flood water level 2.1 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Landside Riverside 100 yr Flood Elevation = 124 ft Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 114 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 3-3B 10+00 Upstream slope stability 100 year flood level 1.6 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Landside Riverside 100 yr Flood Elevation = 124 ft Normal Condition Elevation = 114 ft Groundwater Level = 114 ft Color Name Model Unit Weight (pcf) Cohesion' (psf) Phi' (°) Cohesion R (psf) Phi R (°) Existing_Fill Mohr-Coulomb 120 0 30 1 29 Impervious Fill Mohr-Coulomb 120 0 32 200 10 Pervious Fill Mohr-Coulomb 120 0 32 1 31 Random_Fill Mohr-Coulomb 125 0 34 500 11 Sand Mohr-Coulomb 120 0 30 1 29 Silt_and_Clay Mohr-Coulomb 110 0 28 300 10 Top Soil Mohr-Coulomb 120 0 31 100 10 Varved_Clay Su500psf Mohr-Coulomb 110 500 0.1 505 0 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 3-3C 10+00 Upstream slope stability Rapid Drawdown - 100 year flood level 1.9 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Landside Riverside Normal Condition Elevation = 114 ft Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 114 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 3-4A 10+00 Downstream slope stability Normal Conditions 2.0 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Landside Riverside Normal Condition Elevation = 114 ft Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 114 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 3-4B 10+00 Upstream slope stability Normal Conditions 1.2 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Landside Riverside Normal Condition Elevation = 114 ft Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 114 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 10+00 Downstream slope stability Seismic - Normal Conditions 3-5A 1.2 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Landside Riverside Normal Condition Elevation = 114 ft Su = 540psf (El.90) Su = 660psf (El.70) Groundwater Level = 114 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Silt_and_Clay Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 3-5B 10+00 Upstream slope stability Seismic - Normal Conditions Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Groundwater Level = 110 ft Landside Riverside 100 yr Flood Elevation = 124 ft XY Gradient = 0.29 Color Name Sat Kx (ft/sec) Impervious Fill Pervious Fill Random_Fill Rip_Rap 0.1 Sand 0.000352 Silt 5.8e-07 Top Soil Varved_Clay 2e-07 4.2e-07 0.00016 1.5e-06 4.2e-07 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 4-1 20+00 Seepage Analysis 100 year flood level Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Groundwater Level = 110 ft Landside Riverside Normal Condition Elevation = 111 ftXY Gradient < 0.1 Color Name Sat Kx (ft/sec) Impervious Fill Pervious Fill Random_Fill Rip_Rap 0.1 Sand 0.000352 Silt 5.8e-07 Top Soil Varved_Clay 2e-07 4.2e-07 0.00016 1.5e-06 4.2e-07 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 4-2 20+00 Seepage Analysis Normal Conditions 1.5 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Groundwater Level = 110 ft Landside Riverside 100 yr Flood Elevation = 124 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Rip_Rap Mohr-Coulomb 145 0 40 Sand Mohr-Coulomb 120 0 30 Silt Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 4-3A 20+00 Downstream slope stability 100 year flood water level 2.2 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Groundwater Level = 110 ft Landside Riverside 100 yr Flood Elevation = 124 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Rip_Rap Mohr-Coulomb 145 0 40 Sand Mohr-Coulomb 120 0 30 Silt Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 4-3B 20+00 Upstream slope stability 100 year flood level 1.4 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Groundwater Level = 110 ft Landside Riverside 100 yr Flood Elevation = 124 ft Normal Condition Elevation = 111 ft Color Name Model Unit Weight (pcf) Cohesion' (psf) Phi' (°) Cohesion R (psf) Phi R (°) Impervious Fill Mohr-Coulomb 120 0 32 200 10 Pervious Fill Mohr-Coulomb 120 0 32 1 31 Random_Fill Mohr-Coulomb 125 0 34 500 11 Rip_Rap Mohr-Coulomb 145 0 40 1 39 Sand Mohr-Coulomb 120 0 30 1 29 Silt Mohr-Coulomb 110 0 28 300 10 Top Soil Mohr-Coulomb 120 0 31 100 10 Varved_Clay Su500psf Mohr-Coulomb 110 500 0.1 505 0 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 4-3C 20+00 Upstream slope stability Rapid Drawdown - 100 year flood level 1.7 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Groundwater Level = 110 ft Landside Riverside Normal Condition Elevation = 111 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Rip_Rap Mohr-Coulomb 145 0 40 Sand Mohr-Coulomb 120 0 30 Silt Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 4-4A 20+00 Downstream slope stability Normal Conditions 1.8 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Groundwater Level = 110 ft Landside Riverside Normal Condition Elevation = 111 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Rip_Rap Mohr-Coulomb 145 0 40 Sand Mohr-Coulomb 120 0 30 Silt Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 4-4B 20+00 Upstream slope stability Normal Conditions 1.1 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Groundwater Level = 110 ft Landside Riverside Normal Condition Elevation = 111 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Rip_Rap Mohr-Coulomb 145 0 40 Sand Mohr-Coulomb 120 0 30 Silt Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 4-5A 20+00 Downstream slope stability Seismic - Normal Conditions 1.1 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 Groundwater Level = 110 ft Landside Riverside Normal Condition Elevation = 111 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Rip_Rap Mohr-Coulomb 145 0 40 Sand Mohr-Coulomb 120 0 30 Silt Mohr-Coulomb 110 0 28 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 4-5B 20+00 Upstream slope stability Seismic - Normal Conditions Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 RiversideLandside Groundwater Level = 113 ft 100 yr Flood Elevation = 123 ft 4.2e-07 4.2e-07 0.00016 1.5e-06 5.87e-08 XY Gradient = 0.29 Color Name Sat Kx (ft/sec) Existing_Embank Existing_Fill 0.00043 Impervious Fill Pervious Fill Random_Fill Sand 0.000352 Top Soil Varved_Clay 2e-07 5.87e-08 4.2e-07 0.00016 1.5e-06 4.2e-07 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 5-1 47+00 Seepage Analysis 100 year flood level Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 RiversideLandside Groundwater Level = 113 ft Normal Condition Elevation = 113 ft 4.2e-07 4.2e-07 0.00016 1.5e-06 5.87e-08 XY Gradient < 0.1 Color Name Sat Kx (ft/sec) Existing_Embank Existing_Fill 0.00043 Impervious Fill Pervious Fill Random_Fill Sand 0.000352 Top Soil Varved_Clay 2e-07 5.87e-08 4.2e-07 0.00016 1.5e-06 4.2e-07 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 5-2 47+00 Seepage Analysis Normal Conditions 1.3 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 RiversideLandside Groundwater Level = 113 ft 100 yr Flood Elevation = 123 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Embank Mohr-Coulomb 110 0 28 Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 5-3A 47+00 Downstream slope stability 100 year flood water level 1.5 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 RiversideLandside Groundwater Level = 113 ft 100 yr Flood Elevation = 123 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Embank Mohr-Coulomb 110 0 28 Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 5-3B 47+00 Upstream slope stability 100 year flood level 1.3 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 RiversideLandside Groundwater Level = 113 ft 100 yr Flood Elevation = 123 ft Normal Condition Elevation = 113 ft Color Name Model Unit Weight (pcf) Cohesion' (psf) Phi' (°) Cohesion R (psf) Phi R (°) Existing_Embank Mohr-Coulomb 110 0 28 300 10 Existing_Fill Mohr-Coulomb 120 0 30 1 29 Impervious Fill Mohr-Coulomb 120 0 32 200 10 Pervious Fill Mohr-Coulomb 120 0 32 1 31 Random_Fill Mohr-Coulomb 125 0 34 500 11 Sand Mohr-Coulomb 120 0 30 1 29 Top Soil Mohr-Coulomb 120 0 31 100 10 Varved_Clay Su500psf Mohr-Coulomb 110 500 0.1 505 0 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 5-3C 47+00 Upstream slope stability Rapid Drawdown - 100 year flood level 1.4 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 RiversideLandside Groundwater Level = 113 ft Normal Condition Elevation = 113 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Embank Mohr-Coulomb 110 0 28 Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 5-4A 47+00 Downstream slope stability Normal Conditions 1.6 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 RiversideLandside Groundwater Level = 113 ft Normal Condition Elevation = 113 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Embank Mohr-Coulomb 110 0 28 Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 5-4B 47+00 Upstream slope stability Normal Conditions 1.1 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 RiversideLandside Groundwater Level = 113 ft Normal Condition Elevation = 113 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Embank Mohr-Coulomb 110 0 28 Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 5-5A 47+00 Downstream slope stability Seismic - Normal Conditions 1.2 Distance [ft] 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250Elevation (NAVD) [ft]65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 RiversideLandside Groundwater Level = 113 ft Normal Condition Elevation = 113 ft Color Name Model Unit Weight (pcf) Cohesion Fn Cohesion' (psf) Phi' (°) Existing_Embank Mohr-Coulomb 110 0 28 Existing_Fill Mohr-Coulomb 120 0 30 Impervious Fill Mohr-Coulomb 120 0 32 Pervious Fill Mohr-Coulomb 120 0 32 Random_Fill Mohr-Coulomb 125 0 34 Sand Mohr-Coulomb 120 0 30 Top Soil Mohr-Coulomb 120 0 31 Varved_Clay Spatial Mohr-Coulomb 110 Su (Depth) 0.1 Conneticut River Levee Analyses Sta. GZA GeoEnvironmental, Inc. Engineers and Scientists PREPARED BY: www.gza.com PROJ MGR:CLB DESIGNED BY: CJT DRAWN BY: CJT PREPARED FOR: PROJECT NO.:DATE: FIGURE 01.174343.00 REVIEWED BY: CLB City of Northampton Department of Public Works 10/14/2020 5-5B 47+00 Upstream slope stability Seismic - Normal Conditions