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23-200018662/3/2025 DRAINAGE STUDY HOUSING AUTHORITY OF THE COUNTY OF KERN LETZRING SENIOR HOUSING DECEMBER 2024 23-20001866 2/3/2025 LETZRING SENIOR HOUSING Prepared for: Housing Authority of the County of Kern 601 24th Street Bakersfield, CA 93301 Consultant: 5080 California Avenue, Suite 220 Bakersfield, CA 93309 Contact: Cindy Parra Phone: (661)616-2600 December 2024 © Copyright by Quad Knopf, Inc. Unauthorized use prohibited. Project #230035 23-20001866 2/3/2025 LETZRING SENIOR HOUSING May 2024 HOUSING AUTHORITY OF THE COUNTY OF KERN Page i TABLE OF CONTENTS SECTION 1 - Introduction ............................................................................................................................ 1 SECTION 2 - Climatology and Site Hydrology ....................................................................................... 4 2.1 - Climatology .................................................................................................................................................... 4 2.2 - Hydrologic Soils ........................................................................................................................................... 4 2.3 - Flood Zone ..................................................................................................................................................... 4 SECTION 3 - Methodology ........................................................................................................................... 8 3.1 - Hydrology ....................................................................................................................................................... 8 3.2 - Hydraulic Analysis ...................................................................................................................................... 8 3.3 - Retention Basin ............................................................................................................................................ 8 SECTION 4 - Proposed Piping System...................................................................................................... 9 SECTION 5 - Proposed Retention Basin .................................................................................................. 9 SECTION 6 - Conclusion ............................................................................................................................... 9 SECTION 7 - References ............................................................................................................................. 10 APPENDICES Appendix A City of Bakersfield Storm Drain Standards Appendix B Autodesk Storm and Sanitary Sewer Analysis Hydraulic Calculations Appendix C Autodesk Storm and Sanitary Sewer Analysis Hydraulic Profiles Appendix D Retention Basin Volume Calculations Appendix E ProposedStorm Drain Plan and Profile Appendix F As-built Storm Drain Plans Appendix G Offsite Sump Study Slope Stability Analysis LIST OF FIGURES Figure 1-1 Regional Map .............................................................................................................. 2 Figure 1-2 Vicinity Map................................................................................................................. 3 Figure 2-1 Project Site Hydraulic Soils Map ......................................................................... 5 Figure 2-2 FEMA Floodplain Map ............................................................................................. 6 Figure 3-1 Catchment Areas…………………………………………………………………………….7 23-20001866 2/3/2025 Introduction LETZRING SENIOR HOUSING 05/08/2024 HOUSING AUTHORITY OF THE COUNTY OF KERN Page 1 SECTION 1 - INTRODUCTION Letzring Senior Housing is a proposed 150 unit housing f acility to be developed in one phase by Housing Authority of the County of Kern. The p roject is located on the west side of Letzring Lane, approximately 300ft south of the inters ection of White Lane and Letzring Lane and consists of approximately 5.9 acres. The prope rty is zoned as C2 Commercial. The objective of this drainage study is to conduct a hy draulic analysis of the existing storm drain system and retention basin to verify adequate c apacity to handle the additional runoff directed to the system by developing the project site and provide recommendations if existing storm drain system and basin are found insufficient. 23-20001866 2/3/2025 Introduction LETZRING SENIOR HOUSING 05/08/2024 HOUSING AUTHORITY OF THE COUNTY OF KERN Page 2 Figure 1-1 Regional Map 23-20001866 2/3/2025 Introduction LETZRING SENIOR HOUSING 05/08/2024 HOUSING AUTHORITY OF THE COUNTY OF KERN Page 3 Figure 1-2 Vicinity Map 23-20001866 2/3/2025 Climatology and Site Hydrology LETZRING SENIOR HOUSING 05/08/2024 HOUSING AUTHORITY OF THE COUNTY OF KERN Page 4 SECTION 2 - CLIMATOLOGY AND SITE HYDROLOGY 2.1 - Climatology The climate of the project location is characterized as arid – to- semiarid, with hot summers and mild winters. According to NOAA, the mean annual precipitation for the regions is 8.75 inches. 2.2 - Hydrologic Soils The Hydrologic Soils Group associated with the project is Kimberlina Fine Sand Loan, Group A. According to the soils conservation Service, Group A s oils are characterized by soils having high infiltration rates even when thoroughly wetted, c onsisting chiefly of deep, well to excessively drained sands or gravel. The soil has hig h water transmission and low runoff potential. These soils, which are prevalent in the st reambeds and on-site areas, are excellent for storm water retention basin use. 2.3 - Flood Zone The project site is in Zone X, areas of minimal flooding, as determined by the Federal Emergency Management Agency (FEMA). The FEMA Federal Insurance Rate Map (FIRM) for Community-Panel 06029C2300E, effective September 200 8, shows the project site within the Zone X flood boundary. 23-20001866 2/3/2025 Climatology and Site Hydrology LETZRING SENIOR HOUSING 05/08/2024 HOUSING AUTHORITY OF THE COUNTY OF KERN Page 5 Figure 2-1 Project Site Hydraulic Soils Map 23-20001866 2/3/2025 Climatology and Site Hydrology LETZRING SENIOR HOUSING 05/08/2024 HOUSING AUTHORITY OF THE COUNTY OF KERN Page 6 Figure 2-2 FEMA Floodplain Map 23-20001866 2/3/2025 Climatology and Site Hydrology LETZRING SENIOR HOUSING HOUSING AUTHORITY OF THE COUNTY OF KERN Page 7 Figure 3-1 Catchment Area Diagram 0.59 ac 2.45 ac 4.87 ac 5.58 ac 0.71 ac 3.57 ac 23-20001866 2/3/2025 Δ126 XXX XXXXXXX BUILDING P (TYPE 3)BUILDING R (TYPE 5)BUILDING A (TYPE 1)BUILDING B (TYPE 1)8,912 SFBUIL DI N G C (T YPE 1)8,912 SFBUILDING N (TYPE 2)5,092 SFBUILDING M (TYPE 2)5,092 SFBUILDING L (TYPE 2)5,092 SFBUIL DI N G D (T YPE 2) BUIL DI N G E (T YPE 2) BUILDIN G F (T YPE 2) BUIL DI N G G (TYPE 2) B U I L D I NG H ( T Y P E 2 ) 5, 0 9 2 S F B U I L D I NG J ( T Y P E 2 ) 5, 0 9 2 S F B U I L D I N G K ( T Y P E 2 ) 5, 0 9 2 S F B U I L D I N G Q ( T Y P E 4 )5,092 SF6,939 SF 376.10 FF 3,325 SF376.08FF8,912 SF376.0 FF8,912 SF375.6 FF8,912 SF 375.1 FF5,092 SF376.35 FF5,092 SF376.45 FF5,092 SF376.55 FF5,092 SF376.65 FF5,092 SF376.55 FF5,092 SF 376.66 FF5,092 SF 376.77 FF5, 0 9 2 S F 3 7 7 . 2 3 F F 5, 0 9 2 S F 3 7 7 . 1 1 F F 5, 0 9 2 S F 3 7 7 . 0 3 F F 9, 3 6 3 S F 3 7 6 . 0 5 F F N Ó23-20001866 2/3/2025 Methodology LETZRING SENIOR HOUSING 05/08/2024 HOUSING AUTHORITY OF THE COUNTY OF KERN Page 8 SECTION 3 - METHODOLOGY 3.1 - Hydrology The hydrologic analysis was performed using Autodesk’s Storm and Sanitary Sewer Analysis Program based on the requirements of the Kern County Ra tional Method, as required by City of Bakersfield Subdivision Design Manual. The catchme nt data including area, longest flow path, impervious cover, and roof to gutter time was inpu t into Autodesk’s Storm and Sanitary Sewer Analysis Program to determine time of concentrat ion. SSA was used to create IDF curves based on points taken from NOAA’s Point Precipitation Frequency Estimate table for the project site . See Exhibit 3-1 for Catchment Area Diagram. 3.2 - Hydraulic Analysis The Storm and Sanitary Analysis program was then uti lized for its hydraulic modeling capabilities to calculate hydraulic grade lines (HGL s) (Appendix B and C) for each pipe in the storm drain collection system which was then used to ve rify pipe sizing. The model was run using the hydrodynamic analysis option for the flow rout ing through the pipes. Per City of Bakersfield Standards, the existing and proposed storm drain system is designated a local waterway. Local waterways placed i n closed conduit systems may be designed for full conduit capacity and pressure flow. The hydraulic grade line shall not be less than 0.5-feet below the gutter or inlet surface elevation. Per City of Bakersfield standards which requires the initial tailwater depth to be equal to one half of the total retention basin depth, the initial w ater surface elevation (WSEL) for the entire model was set equal to 362.25, thus simulating the effects of the existing retention basin being half full in the model. 3.3 - Retention Basin Storm water collected at the Letzring Senior Housing De velopment will be directed to the existing retention basin south of the project area. 23-20001866 2/3/2025 Proposed Piping System LETZRING SENIOR HOUSING 05/08/2024 HOUSING AUTHORITY OF THE COUNTY OF KERN Page 9 SECTION 4 - PROPOSED PIPING SYSTEM An overview of the existing and proposed piping system can be found in Figure 3-1. This overview identifies the boundaries of the catchment ar eas as well as indicating the location of all storm drain pipes, manholes, catch basins and r etention basin outlet downstream of the project area. This project will extend the existi ng storm drain system upstream to pick up additional run-off from the Letzring development. T he proposed storm drain was sized for the expected run-off from the development. The exis ting storm drain system was found to be adequate for the increased demand from the Letzr ing project. See Appendix B and C for proposed and existing as-built storm drain plans. SECTION 5 - PROPOSED RETENTION BASIN The existing retention basin for the site was designe d as a regional retention basin with multiple outlet structures. The top of the existing re tention basin is 367.5 feet, the existing retention basin has an existing capacity of 17.1 acre -feet based on a topographic survey completed by QK in July of 2023. The current required capacity based on the City of Bakersfield drainage boundary and runoff values based on zoning is 21.7 acre-feet. The capacity required with the addition of Letzring housi ng project is 22.6 acre-ft. It is recommended that the basin be deepened by 3 feet to increase the basin capacity by 5.5 acre-feet to provide a total capacity of 22.6. The proposed ne w Water Surface Elevation (WSE) is 365.5 and the proposed bottom of basin elevation is 354.7. see appendix E for proposed basin plan. A geotechnical investigation was conducted of the exist ing offsite basin, see Appendix E. Based on slope stability analysis performed during thi s investigation for slopes with a depth up to 20 feet with 2:1 (H:V), there are no soil condit ions that would preclude the construction of the proposed sump. Based on the soil conditions encountered, the existing s ump should drain in 7 days or less, provided the upper 6 inches of silt/sediments at the bottom of the sump is removed. Annual removal of silt build-up at the bottom of the sump shoul d be performed to maintain effective drainage. SECTION 6 - CONCLUSION The onsite storm drain system was analyzed for an aver age recurrence interval of 10-years per the City of Bakersfield Subdivision Design Manual . The existing and proposed drainage system was found adequate to handle the increased flow added by the Letzring project. The existing basin’s capacity (17.1 acre-feet) is exceeded by the current demand of 21.7 acre-feet and will be further exceeded by the Letzring project which will required 22.6 acre-ft. It is recommended that the existing basin be deepened by 3 feet minimum. 23-20001866 2/3/2025 References LETZRING SENIOR HOUSING 05/08/2024 HOUSING AUTHORITY OF THE COUNTY OF KERN Page 10 SECTION 7 - REFERENCES 1. City of Bakersfield. Engineering and Public Works. Su bdivision and Engineering Design Policy Manual. Bakersfield, CA: City of Bakersfield. 2. Kern County. Department of Planning and Development Se rvices. Kern County Hydrology Manual. Bakersfield, California: Kern County, 1992 3. Autodesk Storm and Sanitary Analysis 2020 23-20001866 2/3/2025 APPENDIX A CITY OF BAKERSFIELD STORM DRAIN STANDARDS 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-200018662/3/2025 23-200018662/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 23-20001866 2/3/2025 APPENDIX B AUTODESK STORM AND SANITARY SEWER ANALYSIS HYDRAULIC CALCULATIONS 23-20001866 2/3/2025 PIPE - 10 YEAR 24 HOUR STORM EVENT Element From (Inlet) To (Outlet) Length Inlet Outlet Average Pipe Pipe Manning's Peak Time of Max Design Max Flow / Total ID Node Node Invert Invert Slope Diameter Width Roughness Flow Peak Flow Flow Design Flow Time Elevation Elevation or Height Flow Velocity Capacity Ratio Surcharged Occurrence (ft) (ft) (ft) (%) (inches) (inches) (cfs) (days hh:mm) (ft/sec) (cfs) (min) Link-01 SDMH-01 SDMH-02 245.00 367.00 365.96 0.4200 18.000 18.00 0.0130 3.16 0 00:35 3.31 6.84 0.46 0.00 Link-01A SDMH-01A SDMH-01 9.96 367.05 367.02 0.2500 18.000 18.00 0.0130 2.47 0 00:37 2.67 5.26 0.47 0.00 Link-02 SDMH-02 SDMH-03 211.00 365.96 365.33 0.3000 18.000 18.00 0.0130 3.16 0 00:36 3.08 5.74 0.55 0.00 Link-02A SDMH-02A SDMH-01A 302.84 367.79 367.05 0.2500 18.000 18.00 0.0130 2.46 0 00:36 2.58 5.21 0.47 0.00 Link-03 SDMH-03 SDMH-04 309.00 365.33 364.40 0.3000 18.000 18.00 0.0130 3.12 0 00:38 3.41 5.76 0.54 0.00 Link-03A SDMH-03A SDMH-02A 80.69 367.99 367.79 0.2500 18.000 18.00 0.0130 2.47 0 00:35 2.67 5.26 0.47 0.00 Link-04 Inlet-01 SDMH-01 50.90 367.15 367.00 0.3000 18.000 18.00 0.0130 0.84 0 00:30 2.48 5.75 0.15 0.00 Link-04A SDMH-04A SDMH-03A 104.01 368.25 367.99 0.2500 18.000 18.00 0.0130 2.47 0 00:35 2.49 5.25 0.47 0.00 Link-05 SDMH-04 SDMH-05 223.40 364.40 363.28 0.5000 30.000 30.00 0.0130 8.31 0 00:22 4.54 29.04 0.29 0.00 Link-05A SDMH-05A SDMH-04A 141.45 368.61 368.25 0.2500 18.000 18.00 0.0130 2.47 0 00:34 2.54 5.28 0.47 0.00 Link-06 SDMH-05 SDMH-06 416.70 363.28 361.44 0.4400 30.000 30.00 0.0130 8.29 0 00:23 4.64 27.26 0.30 0.00 Link-06A SDMH-06A SDMH-05A 141.99 368.96 368.61 0.2500 18.000 18.00 0.0150 2.48 0 00:33 2.48 4.53 0.55 0.00 Link-07 SDMH-06 Inlet-07 8.94 361.44 361.23 2.3500 30.000 30.00 0.0130 8.26 0 00:23 7.11 62.86 0.13 0.00 Link-08 Inlet-07 Out-01 94.89 361.23 354.70 6.8800 30.000 30.00 0.0130 8.26 0 00:24 10.59 107.60 0.08 0.00 Link-09 Inlet-02 SDMH-02 31.38 366.05 365.96 0.2900 18.000 18.00 0.0130 0.77 0 00:14 2.20 5.63 0.14 0.00 Link-10 Inlet-03 SDMH-03 15.00 365.41 365.33 0.5300 18.000 18.00 0.0130 1.26 0 00:17 2.61 7.67 0.16 0.00 Link-11 Inlet-04 SDMH-04 50.82 364.67 364.40 0.5300 18.000 18.00 0.0130 1.60 0 00:21 2.01 7.66 0.21 0.00 Link-12 Inlet-06 Inlet-05 66.90 364.88 364.55 0.4900 18.000 18.00 0.0130 2.10 0 00:27 2.07 7.38 0.28 0.00 Link-13 Inlet-05 SDMH-04 26.90 364.55 364.40 0.5600 18.000 18.00 0.0130 3.76 0 00:21 2.95 7.84 0.48 0.00 Link-16 Out-01 Out-02 60.43 365.50 365.50 0.0000 30.000 30.00 0.0130 0.00 0 00:00 0.00 1.67 0.00 0.00 Link-20 SDMH-14A SDMH13A 13.38 369.36 369.33 0.2500 18.000 18.00 0.0130 0.72 0 00:33 1.94 7.03 0.10 0.00 Link-25 CB2 SDMH-09A 26.16 370.83 370.70 0.5000 18.000 18.00 0.0130 0.66 0 00:28 2.35 7.43 0.09 0.00 Link-30 SDMH-09A SDMH-08A 10.37 369.55 369.52 0.2500 18.000 18.00 0.0130 1.38 0 00:39 1.88 5.65 0.24 0.00 Link-45A CB3 SDMH-11A 68.75 371.78 371.25 0.7700 18.000 18.00 0.0130 0.51 0 00:38 2.67 9.19 0.06 0.00 Link-49A CB6 SDMH-16A 98.00 371.01 370.03 1.0000 18.000 18.00 0.0150 0.46 0 00:32 2.64 9.10 0.05 0.00 Link-50A SDMH-12A SDMH-11A 128.61 370.22 369.90 0.2500 18.000 18.00 0.0130 0.58 0 00:47 1.43 5.24 0.11 0.00 Link-51A SDMH-11A SDMH-10A 10.00 369.91 369.88 0.2500 18.000 18.00 0.0130 0.99 0 00:41 2.19 5.25 0.19 0.00 Link-52A SDMH-10A SDMH-09A 50.93 369.78 369.65 0.2500 18.000 18.00 0.0130 0.99 0 00:41 1.95 5.31 0.19 0.00 Link-54A SDMH-08A SDMH-07A 26.23 369.52 369.45 0.2500 18.000 18.00 0.0150 1.38 0 00:39 2.16 4.70 0.29 0.00 Link-55A SDMH-07A SDMH-06A 156.46 369.45 369.06 0.2500 18.000 18.00 0.0130 1.38 0 00:39 2.02 5.25 0.26 0.00 Link-56A CB4 SDMH-12A 12.46 371.31 371.19 1.0000 18.000 18.00 0.0130 0.58 0 00:47 2.78 10.52 0.06 0.00 Link-57A CB1 SDMH-06A 12.52 371.01 370.89 1.0000 18.000 18.00 0.0130 0.46 0 00:29 2.62 10.50 0.04 0.00 Link-58A SDMH-16A SDMH-15A 78.75 369.93 369.74 0.2500 18.000 18.00 0.0130 0.46 0 00:33 1.43 5.16 0.09 0.00 Link-59A SDMH-15A SDMH-14A 98.90 369.74 369.49 0.2500 18.000 18.00 0.0130 0.72 0 00:33 2.08 5.28 0.14 0.00 Link-62A SDMH13A SDMH-06A 68.83 369.23 369.06 0.2500 18.000 18.00 0.0130 0.72 0 00:33 1.05 5.25 0.14 0.00 Link-64A CB5 SDMH-15A 12.50 371.48 371.36 1.0000 18.000 18.00 0.0130 0.32 0 00:27 2.38 10.50 0.03 0.00 23-20001866 2/3/2025 CATCH BASINS - 10 YEAR 24 HOUR STORM EVENT Element Inlet Catchbasin Initial Curb Peak Peak Peak Peak Inlet Total ID Location Invert Water Clogging Flow Lateral Flow Flow Efficiency Time Elevation Depth Factor Inflow Intercepted Bypassing during Flooded by Inlet Inlet Peak Flow (ft) (ft) (%) (cfs) (cfs) (cfs) (cfs) (%) (minutes) CB1 On Sag 371.01 0.00 50.00 0.47 0.45 N/A N/A N/A 0.00 CB2 On Sag 370.42 0.00 50.00 0.66 0.66 N/A N/A N/A 0.00 CB3 On Sag 371.78 0.00 50.00 0.51 0.51 N/A N/A N/A 0.00 CB4 On Sag 371.31 0.00 50.00 0.59 0.59 N/A N/A N/A 0.00 CB5 On Grade 371.48 0.00 50.00 0.33 0.33 0.33 0.00 100.00 0.00 CB6 On Sag 371.01 0.00 50.00 0.47 0.47 N/A N/A N/A 0.00 Inlet-01 On Sag 367.15 0.00 50.00 0.86 0.86 N/A N/A N/A 0.00 Inlet-02 On Sag 365.05 0.00 50.00 0.78 0.78 N/A N/A N/A 0.00 Inlet-03 On Sag 365.33 0.00 50.00 1.27 1.27 N/A N/A N/A 0.00 Inlet-04 On Sag 364.67 0.00 50.00 1.61 1.61 N/A N/A N/A 0.00 Inlet-05 On Sag 364.55 0.00 50.00 2.25 2.25 N/A N/A N/A 0.00 Inlet-06 On Sag 364.88 0.00 50.00 2.09 2.09 N/A N/A N/A 0.00 Inlet-07 On Sag 361.23 0.00 50.00 0.51 0.51 N/A N/A N/A 0.00 23-20001866 2/3/2025 MANHOLES - 10 YEAR 24 HOUR STORM EVENT Element Invert Ground/Rim Initial Initial Surcharge Surcharge Peak Peak Maximum Minimum Total ID Elevation (Max) Water Water Elevation Depth Inflow Lateral HGL Freeboard Time Elevation Elevation Depth Inflow Elevation Attained Flooded Attained (ft) (ft) (ft) (ft) (ft) (ft) (cfs) (cfs) (ft) (ft) (minutes) SDMH-01 367.00 371.74 367.00 0.00 371.74 0.00 3.16 0.00 367.74 4.00 0.00 SDMH-01A 367.04 371.80 367.04 0.00 371.80 0.00 2.46 0.00 367.90 3.90 0.00 SDMH-02 365.96 372.10 365.96 0.00 372.10 0.00 3.17 0.00 366.82 5.28 0.00 SDMH-02A 367.79 372.70 367.79 0.00 372.70 0.00 2.47 0.00 368.53 4.17 0.00 SDMH-03 365.33 371.40 365.33 0.00 371.40 0.00 3.16 0.00 366.18 5.22 0.00 SDMH-03A 367.99 373.20 367.99 0.00 373.20 0.00 2.47 0.00 368.81 4.39 0.00 SDMH-04 364.40 369.80 364.40 0.00 369.80 0.00 8.34 0.00 365.40 4.40 0.00 SDMH-04A 368.25 374.00 368.25 0.00 374.00 0.00 2.47 0.00 369.08 4.92 0.00 SDMH-05 363.28 370.70 363.28 0.00 370.70 0.00 8.31 0.00 364.28 6.42 0.00 SDMH-05A 368.61 374.80 368.61 0.00 374.80 0.00 2.48 0.00 369.41 5.39 0.00 SDMH-06 361.44 371.30 361.44 0.00 371.30 0.00 8.29 0.00 362.40 8.90 0.00 SDMH-06A 368.89 374.90 368.89 0.00 374.90 0.00 2.48 0.00 369.82 5.08 0.00 SDMH-07A 369.45 374.80 369.45 0.00 374.80 0.00 1.38 0.00 370.00 4.80 0.00 SDMH-08A 369.52 374.70 369.52 0.00 374.70 0.00 1.38 0.00 370.15 4.55 0.00 SDMH-09A 369.55 374.70 369.55 0.00 374.70 0.00 1.38 0.00 370.22 4.48 0.00 SDMH-10A 369.78 375.40 369.78 0.00 375.40 0.00 0.99 0.00 370.31 5.09 0.00 SDMH-11A 369.80 375.60 369.80 0.00 375.60 0.00 0.98 0.00 370.42 5.18 0.00 SDMH-12A 370.12 375.67 370.12 0.00 375.67 0.00 0.58 0.00 370.56 5.11 0.00 SDMH13A 369.23 375.40 369.23 0.00 375.40 0.00 0.72 0.00 369.84 5.56 0.00 SDMH-14A 369.39 375.50 369.39 0.00 375.50 0.00 0.72 0.00 369.88 5.62 0.00 SDMH-15A 369.74 375.80 369.74 0.00 375.80 0.00 0.72 0.00 370.14 5.66 0.00 SDMH-16A 369.93 375.60 369.93 0.00 375.60 0.00 0.46 0.00 370.25 5.35 0.00 23-20001866 2/3/2025 CATCHMENT AREAS - 10 YEAR 24 HOUR STORM EVENT Element Area Drainage Weighted Accumulated Total Peak Rainfall Time ID Node ID Runoff Precipitation Runoff Runoff Intensity of Coefficient Concentration (acres) (inches) (inches) (cfs) (inches/hr) (days hh:mm:ss) Sub-01 0.59 Inlet-01 0.4000 0.28 0.11 0.55 2.341 0 00:07:13 Sub-02 1.34 Inlet-02 0.4000 0.35 0.14 0.78 1.456 0 00:14:21 Sub-03 2.45 Inlet-03 0.4000 0.37 0.15 1.27 1.295 0 00:16:57 Sub-04 3.57 Inlet-04 0.4000 0.40 0.16 1.61 1.125 0 00:21:09 Sub-05 4.87 Inlet-05 0.4000 0.39 0.16 2.25 1.157 0 00:20:14 Sub-06 5.45 Inlet-06 0.4000 0.43 0.17 2.09 0.957 0 00:27:13 Sub-07 0.71 Inlet-07 0.4000 0.34 0.14 0.51 1.770 0 00:11:29 Sub-11 52.41 Out-01 0.4000 0.42 0.17 21.17 1.010 0 00:25:03 Sub-12 89.18 Out-01 0.9000 0.45 0.41 72.25 0.900 0 00:29:59 Sub-13 61.89 Out-01 0.5500 0.45 0.25 30.64 0.900 0 00:29:59 Sub-15 0.76 CB6 0.7200 0.46 0.33 0.47 0.857 0 00:32:23 Sub-16 0.68 CB1 0.7200 0.44 0.32 0.45 0.928 0 00:28:34 Sub-17 1.20 CB4 0.7200 0.53 0.38 0.59 0.677 0 00:46:58 Sub-18 0.92 CB3 0.7200 0.49 0.35 0.51 0.770 0 00:38:21 Sub-19 0.97 CB2 0.7200 0.44 0.32 0.66 0.943 0 00:27:52 Sub-20 1.32 Inlet-01 0.7200 0.45 0.32 0.86 0.900 0 00:30:00 Sub-21 0.48 CB5 0.7200 0.44 0.31 0.33 0.957 0 00:27:15 23-20001866 2/3/2025 PIPE - BASIN FILLED TO 50% - 10 YEAR 24 HOUR STORM EVENT Element From (Inlet) To (Outlet) Length Inlet Outlet Average Pipe Pipe Manning's Peak Time of Max Design Max Flow / Total ID Node Node Invert Invert Slope Diameter Width Roughness Flow Peak Flow Flow Design Flow Time Elevation Elevation or Height Flow Velocity Capacity Ratio Surcharged Occurrence (ft) (ft) (ft) (%) (inches) (inches) (cfs) (days hh:mm) (ft/sec) (cfs) (min) Link-01 SDMH-01 SDMH-02 245.00 367.00 365.96 0.4200 18.000 18.00 0.0130 3.50 0 00:34 3.39 6.84 0.51 0.00 Link-01A SDMH-01A SDMH-01 9.96 367.05 367.02 0.2500 18.000 18.00 0.0130 2.47 0 00:37 2.57 5.26 0.47 0.00 Link-02 SDMH-02 SDMH-03 211.00 365.96 365.33 0.3000 18.000 18.00 0.0130 3.49 0 00:35 3.12 5.74 0.61 0.00 Link-02A SDMH-02A SDMH-01A 302.84 367.79 367.05 0.2500 18.000 18.00 0.0130 2.46 0 00:36 2.55 5.21 0.47 0.00 Link-03 SDMH-03 SDMH-04 309.00 365.33 364.40 0.3000 18.000 18.00 0.0130 3.46 0 00:37 3.49 5.76 0.60 0.00 Link-03A SDMH-03A SDMH-02A 80.69 367.99 367.79 0.2500 18.000 18.00 0.0130 2.47 0 00:35 2.69 5.26 0.47 0.00 Link-04 Inlet-01 SDMH-01 50.90 367.15 367.00 0.3000 18.000 18.00 0.0130 1.22 0 00:30 2.55 5.75 0.21 0.00 Link-04A SDMH-04A SDMH-03A 104.01 368.25 367.99 0.2500 18.000 18.00 0.0130 2.47 0 00:34 2.49 5.25 0.47 0.00 Link-05 SDMH-04 SDMH-05 223.40 364.40 363.28 0.5000 30.000 30.00 0.0130 8.54 0 00:22 4.57 29.04 0.29 0.00 Link-05A SDMH-05A SDMH-04A 141.45 368.61 368.25 0.2500 18.000 18.00 0.0130 2.47 0 00:34 2.54 5.28 0.47 0.00 Link-06 SDMH-05 SDMH-06 416.70 363.28 361.44 0.4400 30.000 30.00 0.0130 8.51 0 00:23 4.67 27.26 0.31 0.00 Link-06A SDMH-06A SDMH-05A 141.99 368.96 368.61 0.2500 18.000 18.00 0.0150 2.48 0 00:33 2.48 4.53 0.55 0.00 Link-07 SDMH-06 Inlet-07 8.94 361.44 361.23 2.3500 30.000 30.00 0.0130 8.49 0 00:23 7.16 62.86 0.14 0.00 Link-08 Inlet-07 Out-01 94.89 361.23 354.70 6.8800 30.000 30.00 0.0130 8.49 0 00:24 2.79 107.60 0.08 0.00 Link-09 Inlet-02 SDMH-02 31.38 366.05 365.96 0.2900 18.000 18.00 0.0130 0.77 0 00:14 2.14 5.63 0.14 0.00 Link-10 Inlet-03 SDMH-03 15.00 365.41 365.33 0.5300 18.000 18.00 0.0130 1.26 0 00:17 2.61 7.67 0.16 0.00 Link-11 Inlet-04 SDMH-04 50.82 364.67 364.40 0.5300 18.000 18.00 0.0130 1.60 0 00:21 2.01 7.66 0.21 0.00 Link-12 Inlet-06 Inlet-05 66.90 364.88 364.55 0.4900 18.000 18.00 0.0130 2.10 0 00:27 2.01 7.38 0.28 0.00 Link-13 Inlet-05 SDMH-04 26.90 364.55 364.40 0.5600 18.000 18.00 0.0130 3.76 0 00:21 2.91 7.84 0.48 0.00 Link-20 SDMH-14A SDMH13A 13.38 369.36 369.33 0.2500 18.000 18.00 0.0130 0.72 0 00:33 1.94 7.03 0.10 0.00 Link-25 CB2 SDMH-09A 26.16 370.83 370.70 0.5000 18.000 18.00 0.0130 0.66 0 00:28 2.35 7.43 0.09 0.00 Link-30 SDMH-09A SDMH-08A 10.37 369.55 369.52 0.2500 18.000 18.00 0.0130 1.38 0 00:39 1.88 5.65 0.24 0.00 Link-45A CB3 SDMH-11A 68.75 371.78 371.25 0.7700 18.000 18.00 0.0130 0.51 0 00:38 2.67 9.19 0.06 0.00 Link-49A CB6 SDMH-16A 98.00 371.01 370.03 1.0000 18.000 18.00 0.0150 0.46 0 00:32 2.64 9.10 0.05 0.00 Link-50A SDMH-12A SDMH-11A 128.61 370.22 369.90 0.2500 18.000 18.00 0.0130 0.58 0 00:47 1.43 5.24 0.11 0.00 Link-51A SDMH-11A SDMH-10A 10.00 369.91 369.88 0.2500 18.000 18.00 0.0130 0.99 0 00:41 2.19 5.25 0.19 0.00 Link-52A SDMH-10A SDMH-09A 50.93 369.78 369.65 0.2500 18.000 18.00 0.0130 0.99 0 00:41 1.95 5.31 0.19 0.00 Link-54A SDMH-08A SDMH-07A 26.23 369.52 369.45 0.2500 18.000 18.00 0.0150 1.38 0 00:39 2.16 4.70 0.29 0.00 Link-55A SDMH-07A SDMH-06A 156.46 369.45 369.06 0.2500 18.000 18.00 0.0130 1.38 0 00:39 2.02 5.25 0.26 0.00 Link-56A CB4 SDMH-12A 12.46 371.31 371.19 1.0000 18.000 18.00 0.0130 0.58 0 00:47 2.78 10.52 0.06 0.00 Link-57A CB1 SDMH-06A 12.52 371.01 370.89 1.0000 18.000 18.00 0.0130 0.46 0 00:29 2.62 10.50 0.04 0.00 Link-58A SDMH-16A SDMH-15A 78.75 369.93 369.74 0.2500 18.000 18.00 0.0130 0.46 0 00:33 1.43 5.16 0.09 0.00 Link-59A SDMH-15A SDMH-14A 98.90 369.74 369.49 0.2500 18.000 18.00 0.0130 0.72 0 00:33 2.08 5.28 0.14 0.00 Link-62A SDMH13A SDMH-06A 68.83 369.23 369.06 0.2500 18.000 18.00 0.0130 0.72 0 00:33 1.05 5.25 0.14 0.00 Link-64A CB5 SDMH-15A 12.50 371.48 371.36 1.0000 18.000 18.00 0.0130 0.32 0 00:27 2.38 10.50 0.03 0.00 23-20001866 2/3/2025 CATCH BASINS - BASIN FILLED TO 50% CAPACITY - 10 YEAR 24 HOUR STORM EVENT Element Inlet Catchbasin Initial Curb Peak Peak Peak Peak Inlet Total ID Location Invert Water Clogging Flow Lateral Flow Flow Efficiency Time Elevation Depth Factor Inflow Intercepted Bypassing during Flooded by Inlet Inlet Peak Flow (ft) (ft) (%) (cfs) (cfs) (cfs) (cfs) (%) (minutes) CB1 On Sag 371.01 0.00 50.00 0.47 0.45 N/A N/A N/A 0.00 CB2 On Sag 370.42 0.00 50.00 0.66 0.66 N/A N/A N/A 0.00 CB3 On Sag 371.78 0.00 50.00 0.51 0.51 N/A N/A N/A 0.00 CB4 On Sag 371.31 0.00 50.00 0.59 0.59 N/A N/A N/A 0.00 CB5 On Grade 371.48 0.00 50.00 0.33 0.33 0.33 0.00 100.00 0.00 CB6 On Sag 371.01 0.00 50.00 0.47 0.47 N/A N/A N/A 0.00 Inlet-01 On Sag 367.15 0.00 50.00 1.24 1.24 N/A N/A N/A 0.00 Inlet-02 On Sag 365.05 0.00 50.00 0.78 0.78 N/A N/A N/A 0.00 Inlet-03 On Sag 365.33 0.00 50.00 1.27 1.27 N/A N/A N/A 0.00 Inlet-04 On Sag 364.67 0.00 50.00 1.61 1.61 N/A N/A N/A 0.00 Inlet-05 On Sag 364.55 0.00 50.00 2.25 2.25 N/A N/A N/A 0.00 Inlet-06 On Sag 364.88 0.00 50.00 2.09 2.09 N/A N/A N/A 0.00 Inlet-07 On Sag 361.23 0.00 50.00 0.51 0.51 N/A N/A N/A 0.00 23-20001866 2/3/2025 MANHOLES - BASIN FILLED TO 50% CAPACITY - 10 YEAR 24 HOUR STORM EVENT Element Invert Ground/Rim Initial Initial Surcharge Surcharge Peak Peak Maximum Minimum Total ID Elevation (Max) Water Water Elevation Depth Inflow Lateral HGL Freeboard Time Elevation Elevation Depth Inflow Elevation Attained Flooded Attained (ft) (ft) (ft) (ft) (ft) (ft) (cfs) (cfs) (ft) (ft) (minutes) SDMH-01 367.00 371.74 367.00 0.00 371.74 0.00 3.50 0.00 367.79 3.95 0.00 SDMH-01A 367.04 371.80 367.04 0.00 371.80 0.00 2.46 0.00 367.93 3.87 0.00 SDMH-02 365.96 372.10 365.96 0.00 372.10 0.00 3.50 0.00 366.88 5.22 0.00 SDMH-02A 367.79 372.70 367.79 0.00 372.70 0.00 2.47 0.00 368.52 4.18 0.00 SDMH-03 365.33 371.40 365.33 0.00 371.40 0.00 3.49 0.00 366.24 5.16 0.00 SDMH-03A 367.99 373.20 367.99 0.00 373.20 0.00 2.47 0.00 368.81 4.39 0.00 SDMH-04 364.40 369.80 364.40 0.00 369.80 0.00 8.56 0.00 365.42 4.38 0.00 SDMH-04A 368.25 374.00 368.25 0.00 374.00 0.00 2.47 0.00 369.08 4.92 0.00 SDMH-05 363.28 370.70 363.28 0.00 370.70 0.00 8.54 0.00 364.29 6.41 0.00 SDMH-05A 368.61 374.80 368.61 0.00 374.80 0.00 2.48 0.00 369.41 5.39 0.00 SDMH-06 361.44 371.30 360.10 -1.34 371.30 0.00 8.51 0.00 362.42 8.88 0.00 SDMH-06A 368.89 374.90 368.89 0.00 374.90 0.00 2.48 0.00 369.82 5.08 0.00 SDMH-07A 369.45 374.80 369.45 0.00 374.80 0.00 1.38 0.00 370.00 4.80 0.00 SDMH-08A 369.52 374.70 369.52 0.00 374.70 0.00 1.38 0.00 370.15 4.55 0.00 SDMH-09A 369.55 374.70 369.55 0.00 374.70 0.00 1.38 0.00 370.22 4.48 0.00 SDMH-10A 369.78 375.40 369.78 0.00 375.40 0.00 0.99 0.00 370.31 5.09 0.00 SDMH-11A 369.80 375.60 369.80 0.00 375.60 0.00 0.98 0.00 370.42 5.18 0.00 SDMH-12A 370.12 375.67 370.12 0.00 375.67 0.00 0.58 0.00 370.56 5.11 0.00 SDMH13A 369.23 375.40 369.23 0.00 375.40 0.00 0.72 0.00 369.84 5.56 0.00 SDMH-14A 369.39 375.50 369.39 0.00 375.50 0.00 0.72 0.00 369.88 5.62 0.00 SDMH-15A 369.74 375.80 369.74 0.00 375.80 0.00 0.72 0.00 370.14 5.66 0.00 SDMH-16A 369.93 375.60 369.93 0.00 375.60 0.00 0.46 0.00 370.25 5.35 0.00 23-20001866 2/3/2025 CATCHMENT AREAS - BASIN FILLED TO 50% CAPACITY - 10 YEAR 24 HOUR STORM EVENT Element Area Drainage Weighted Accumulated Total Peak Rainfall Time ID Node ID Runoff Precipitation Runoff Runoff Intensity of Coefficient Concentration (acres) (inches) (inches) (cfs) (inches/hr) (days hh:mm:ss) Sub-01 0.59 Inlet-01 0.4000 0.28 0.11 0.55 2.341 0 00:07:13 Sub-02 1.34 Inlet-02 0.4000 0.35 0.14 0.78 1.456 0 00:14:21 Sub-03 2.45 Inlet-03 0.4000 0.37 0.15 1.27 1.295 0 00:16:57 Sub-04 3.57 Inlet-04 0.4000 0.40 0.16 1.61 1.125 0 00:21:09 Sub-05 4.87 Inlet-05 0.4000 0.39 0.16 2.25 1.157 0 00:20:14 Sub-06 5.45 Inlet-06 0.4000 0.43 0.17 2.09 0.957 0 00:27:13 Sub-07 0.71 Inlet-07 0.4000 0.34 0.14 0.51 1.770 0 00:11:29 Sub-11 52.41 Out-01 0.4000 0.42 0.17 21.17 1.010 0 00:25:03 Sub-12 89.18 Out-01 0.9000 0.45 0.41 72.25 0.900 0 00:29:59 Sub-13 61.89 Out-01 0.5500 0.45 0.25 30.64 0.900 0 00:29:59 Sub-15 0.76 CB6 0.7200 0.46 0.33 0.47 0.857 0 00:32:23 Sub-16 0.68 CB1 0.7200 0.44 0.32 0.45 0.928 0 00:28:34 Sub-17 1.20 CB4 0.7200 0.53 0.38 0.59 0.677 0 00:46:58 Sub-18 0.92 CB3 0.7200 0.49 0.35 0.51 0.770 0 00:38:21 Sub-19 0.97 CB2 0.7200 0.44 0.32 0.66 0.943 0 00:27:52 Sub-20 1.91 Inlet-01 0.7200 0.45 0.32 1.24 0.900 0 00:30:00 Sub-21 0.48 CB5 0.7200 0.44 0.31 0.33 0.957 0 00:27:15 23-20001866 2/3/2025 APPENDIX C AUTODESK STORM AND SANITARY SEWER ANALYSIS HYDRAULIC PROFILES 23-20001866 2/3/2025 1+00 1+50 2+00 2+50 3+00 3+50 4+00 4+50 5+00 Station (ft) 367 368 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:SDMH-12A 375.67 370.12 SDMH-11A 375.60 369.80 SDMH-10A 375.40 369.78 SDMH-09A 374.70 369.55 SDMH-08A 374.70 369.52 SDMH-07A 374.80 369.45 SDMH-06A 374.90 368.89 Link-50A 0.0025 0.58 1.43 128.61 18.00 0.42 Link-51A 0.0025 0.99 2.19 10.00 18.00 0.47 Link-52A 0.0025 0.99 1.95 50.93 18.00 0.55 Link-30 0.0025 1.38 1.88 10.37 18.00 0.65 Link-54A 0.0025 1.38 2.16 26.23 18.00 0.59 Link-55A 0.0025 1.38 2.02 156.46 18.00 0.65 370.22 369.90 369.90 369.88 369.78 369.65 369.55 369.52 369.52 369.45 369.45 369.06 2.98 370.56 2.85 370.42 4.02 370.31 2.50 370.22 3.68 370.15 3.85 370.00 2.51 369.82 1+00 1+50 2+00 2+50 3+00 3+50 4+00 Station (ft) 367 368 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:SDMH-16A 375.60 369.93 SDMH-15A 375.80 369.74 SDMH-14A 375.50 369.39 SDMH13A 375.40 369.23 SDMH-06A 374.90 368.89 Link-58A 0.0025 0.46 1.43 78.75 18.00 0.36 Link-59A 0.0025 0.72 2.08 98.90 18.00 0.39 Link-20 0.0025 0.72 1.94 13.38 18.00 0.50 Link-62A 0.0025 0.72 1.05 68.83 18.00 0.69 369.93 369.74 369.74 369.49 369.36 369.33 369.23 369.06 4.07 370.25 2.95 370.14 4.51 369.88 4.57 369.84 2.51 369.82 23-20001866 2/3/2025 1+00 Station (ft) 368 369 370 371 372 373 374 375 376 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB2 374.30 370.42 SDMH-09A 374.70 369.55 Link-25 0.0050 0.66 2.35 26.16 18.00 0.32 370.83 370.70 372.39 371.18 2.50 370.22 1+50 1+00 1+50 Station (ft) 368 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB3 374.30 371.78 SDMH-11A 375.60 369.80 Link-45A 0.0077 0.51 2.67 68.75 18.00 0.25 371.78 371.25 372.80 372.03 2.85 370.42 2+00 1+00 Station (ft) 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB4 375.69 371.31 SDMH-12A 375.67 370.12 Link-56A 0.0100 0.58 2.78 12.46 18.00 0.26 371.31 371.18 374.19 371.60 2.98 370.56 1+50 1+00 Station (ft) 368 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB5 375.85 371.48 SDMH-15A 375.80 369.74 Link-64A 0.0100 0.32 2.38 12.50 18.00 0.19 371.48 371.36 374.35 371.69 2.95 370.14 1+50 1+00 1+50 2+00 Station (ft) 368 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB6 374.88 371.01 SDMH-16A 375.60 369.93 Link-49A 0.0100 0.46 2.64 98.00 18.00 0.23 371.01 370.03 373.38 371.25 4.07 370.25 1+00 Station (ft) 367 368 369 370 371 372 373 374 375 376 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB1 374.89 371.01 SDMH-06A 374.90 368.89 Link-57A 0.0100 0.46 2.62 12.52 18.00 0.23 371.01 370.88 373.39 371.26 2.51 369.82 1+50 23-20001866 2/3/2025 1+00 2+00 3+00 4+00 5+00 6+00 7+00 8+00 9+00 Station (ft) 366 367 368 369 370 371 372 373 374 375 376 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:SDMH-06A 374.90 368.89 SDMH-05A 374.80 368.61 SDMH-04A 374.00 368.25 SDMH-03A 373.20 367.99 SDMH-02A 372.70 367.79 SDMH-01A 371.80 367.04 SDMH-01 371.74 367.00 Link-06A 0.0025 2.48 2.48 141.99 18.00 0.83 Link-05A 0.0025 2.47 2.54 141.45 18.00 0.81 Link-04A 0.0025 2.47 2.49 104.01 18.00 0.82 Link-03A 0.0025 2.47 2.67 80.69 18.00 0.78 Link-02A 0.0025 2.46 2.58 302.84 18.00 0.80 Link-01A 0.0025 2.47 2.67 9.96 18.00 0.79 368.96 368.61 368.61 368.25 368.25 367.99 367.99 367.79 367.79 367.04 367.04 367.02 2.51 369.82 4.69 369.41 4.25 369.08 3.71 368.81 3.41 368.53 3.26 367.90 3.22 367.74 23-20001866 2/3/2025 1+00 2+50 4+00 5+50 7+00 8+50 Station (ft) SDMH-01 371.74 367.00 SDMH-02 372.10 365.96 SDMH-03 371.40 365.33 SDMH-04 369.80 364.40 Link-01 0.0042 3.16 3.31 245.00 18.00 0.80 Link-02 0.0030 3.16 3.08 211.00 18.00 0.85 Link-03 0.0030 3.12 3.41 309.00 18.00 0.88 367.00 365.96 365.96 365.33 365.33 364.40 3.22 367.74 4.64 366.82 4.57 366.18 2.90 365.40 359 361 363 365 367 369 371 373 375 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID: 23-20001866 2/3/2025 359 361 363 365 367 369 371 373 375 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID: 10+00 11+50 13+00 14+50 16+00 SDMH-05 370.70 363.28 SDMH-06 371.30 361.44 Inlet-07 370.25 361.23 Link-05 0.0050 8.31 4.54 223.40 30.00 1.00 Link-06 0.0044 8.29 4.64 416.70 30.00 0.98 Link-07 0.0235 8.26 7.11 8.94 30.00 0.72 364.40 363.28 363.28 361.44 361.44 361.23 4.92 364.28 7.36 362.40 367.75 361.70 23-20001866 2/3/2025 1+00 Station (ft) 363 364 365 366 367 368 369 370 371 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:Inlet-06 368.88 364.88 Inlet-05 368.78 364.55 SDMH-04 369.80 364.40 Inlet-04 369.45 364.67 Link-12 0.0049 2.10 2.07 66.90 18.00 0.91 Link-13 0.0056 3.76 2.95 26.90 18.00 1.02 Link-11 0.0053 1.60 2.01 50.82 18.00 0.89 364.88 364.55 364.55 364.40 364.67 364.40 367.38 365.65 367.28 365.60 2.90 365.40 367.95 365.44 1+50 2+00 2+50 1+00 Station (ft) 364 365 366 367 368 369 370 371 372 373 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:Inlet-03 370.73 365.33 SDMH-03 371.40 365.33 Link-10 0.0053 1.26 2.61 15.00 18.00 0.81 365.41 365.33 369.15 366.18 4.57 366.18 1+50 1+00 Station (ft) 364 365 366 367 368 369 370 371 372 373 374 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:Inlet-02 371.55 365.05 SDMH-02 372.10 365.96 Link-09 0.0029 0.77 2.20 31.38 18.00 0.82 366.05 365.96 369.05 366.82 4.64 366.82 1+50 1+00 1+50 Station (ft) 366 367 368 369 370 371 372 373 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:Inlet-01 371.25 367.15 SDMH-01 371.74 367.00 Link-04 0.0030 0.84 2.48 50.90 18.00 0.67 367.15 367.00 369.75 367.76 3.22 367.74 23-20001866 2/3/2025 1+00 2+00 3+00 4+00 5+00 6+00 7+00 8+00 9+00 Station (ft) 366 367 368 369 370 371 372 373 374 375 376 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:SDMH-06A 374.90 368.89 SDMH-05A 374.80 368.61 SDMH-04A 374.00 368.25 SDMH-03A 373.20 367.99 SDMH-02A 372.70 367.79 SDMH-01A 371.80 367.04 SDMH-01 371.74 367.00 Link-06A 0.0025 2.48 2.48 141.99 18.00 0.83 Link-05A 0.0025 2.47 2.54 141.45 18.00 0.81 Link-04A 0.0025 2.47 2.49 104.01 18.00 0.82 Link-03A 0.0025 2.47 2.69 80.69 18.00 0.78 Link-02A 0.0025 2.46 2.55 302.84 18.00 0.81 Link-01A 0.0025 2.47 2.57 9.96 18.00 0.82 368.96 368.61 368.61 368.25 368.25 367.99 367.99 367.79 367.79 367.04 367.04 367.02 2.51 369.82 4.69 369.41 4.25 369.08 3.71 368.81 3.41 368.52 3.26 367.93 3.22 367.79 23-20001866 2/3/2025 1+00 1+50 2+00 2+50 3+00 3+50 4+00 4+50 5+00 Station (ft) 367 368 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:SDMH-12A 375.67 370.12 SDMH-11A 375.60 369.80 SDMH-10A 375.40 369.78 SDMH-09A 374.70 369.55 SDMH-08A 374.70 369.52 SDMH-07A 374.80 369.45 SDMH-06A 374.90 368.89 Link-50A 0.0025 0.58 1.43 128.61 18.00 0.42 Link-51A 0.0025 0.99 2.19 10.00 18.00 0.47 Link-52A 0.0025 0.99 1.95 50.93 18.00 0.55 Link-30 0.0025 1.38 1.88 10.37 18.00 0.65 Link-54A 0.0025 1.38 2.16 26.23 18.00 0.59 Link-55A 0.0025 1.38 2.02 156.46 18.00 0.65 370.22 369.90 369.90 369.88 369.78 369.65 369.55 369.52 369.52 369.45 369.45 369.06 2.98 370.56 2.85 370.42 4.02 370.31 2.50 370.22 3.68 370.15 3.85 370.00 2.51 369.82 1+00 1+50 2+00 2+50 3+00 3+50 4+00 Station (ft) 367 368 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:SDMH-16A 375.60 369.93 SDMH-15A 375.80 369.74 SDMH-14A 375.50 369.39 SDMH13A 375.40 369.23 SDMH-06A 374.90 368.89 Link-58A 0.0025 0.46 1.43 78.75 18.00 0.36 Link-59A 0.0025 0.72 2.08 98.90 18.00 0.39 Link-20 0.0025 0.72 1.94 13.38 18.00 0.50 Link-62A 0.0025 0.72 1.05 68.83 18.00 0.69 369.93 369.74 369.74 369.49 369.36 369.33 369.23 369.06 4.07 370.25 2.95 370.14 4.51 369.88 4.57 369.84 2.51 369.82 23-20001866 2/3/2025 1+00 Station (ft) 368 369 370 371 372 373 374 375 376 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB2 374.30 370.42 SDMH-09A 374.70 369.55 Link-25 0.0050 0.66 2.35 26.16 18.00 0.32 370.83 370.70 372.39 371.18 2.50 370.22 1+50 1+00 1+50 Station (ft) 368 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB3 374.30 371.78 SDMH-11A 375.60 369.80 Link-45A 0.0077 0.51 2.67 68.75 18.00 0.25 371.78 371.25 372.80 372.03 2.85 370.42 2+00 1+00 Station (ft) 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB4 375.69 371.31 SDMH-12A 375.67 370.12 Link-56A 0.0100 0.58 2.78 12.46 18.00 0.26 371.31 371.18 374.19 371.60 2.98 370.56 1+50 1+00 Station (ft) 368 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB5 375.85 371.48 SDMH-15A 375.80 369.74 Link-64A 0.0100 0.32 2.38 12.50 18.00 0.19 371.48 371.36 374.35 371.69 2.95 370.14 1+50 1+00 1+50 2+00 Station (ft) 368 369 370 371 372 373 374 375 376 377 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB6 374.88 371.01 SDMH-16A 375.60 369.93 Link-49A 0.0100 0.46 2.64 98.00 18.00 0.23 371.01 370.03 373.38 371.25 4.07 370.25 1+00 Station (ft) 367 368 369 370 371 372 373 374 375 376 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:CB1 374.89 371.01 SDMH-06A 374.90 368.89 Link-57A 0.0100 0.46 2.62 12.52 18.00 0.23 371.01 370.88 373.39 371.26 2.51 369.82 1+50 23-20001866 2/3/2025 359 361 363 365 367 369 371 373 375 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID: 1+00 2+50 4+00 5+50 7+00 8+50 Station (ft) SDMH-01 371.74 367.00 SDMH-02 372.10 365.96 SDMH-03 371.40 365.33 SDMH-04 369.80 364.40 Link-01 0.0042 3.50 3.39 245.00 18.00 0.85 Link-02 0.0030 3.49 3.12 211.00 18.00 0.91 Link-03 0.0030 3.46 3.49 309.00 18.00 0.91 367.00 365.96 365.96 365.33 365.33 364.40 3.22 367.79 4.64 366.88 4.57 366.24 2.90 365.42 23-20001866 2/3/2025 359 361 363 365 367 369 371 373 375 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID: 10+00 11+50 13+00 14+50 16+00 SDMH-05 370.70 363.28 SDMH-06 371.30 361.44 Inlet-07 370.25 361.23 Link-05 0.0050 8.54 4.57 223.40 30.00 1.02 Link-06 0.0044 8.51 4.67 416.70 30.00 1.00 Link-07 0.0235 8.49 7.16 8.94 30.00 0.97 364.40 363.28 363.28 361.44 361.44 361.23 4.92 364.29 7.36 362.42 367.75 362.30 23-20001866 2/3/2025 1+00 2+00 Station (ft) 363 364 365 366 367 368 369 370 371 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:Inlet-06 368.88 364.88 Inlet-05 368.78 364.55 SDMH-04 369.80 364.40 Inlet-04 369.45 364.67 Link-12 0.0049 2.10 2.01 66.90 18.00 0.92 Link-13 0.0056 3.76 2.91 26.90 18.00 1.04 Link-11 0.0053 1.60 2.01 50.82 18.00 0.90 364.88 364.55 364.55 364.40 364.67 364.40 367.38 365.66 367.28 365.61 2.90 365.42 367.95 365.46 1+50 2+50 1+00 Station (ft) 364 365 366 367 368 369 370 371 372 373 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:Inlet-03 370.73 365.33 SDMH-03 371.40 365.33 Link-10 0.0053 1.26 2.61 15.00 18.00 0.87 365.41 365.33 369.15 366.24 4.57 366.24 1+50 1+00 Station (ft) 364 365 366 367 368 369 370 371 372 373 374 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:Inlet-02 371.55 365.05 SDMH-02 372.10 365.96 Link-09 0.0029 0.77 2.14 31.38 18.00 0.88 366.05 365.96 369.05 366.88 4.64 366.88 1+50 1+00 1+50 Station (ft) 366 367 368 369 370 371 372 373 Elevation (ft)Max Depth (ft): Max Vel (ft/s): Max Q (cfs): Dn Invert (ft): Up Invert (ft): Slope (ft/ft): Dia (in): Length (ft): Link ID: Max HGL (ft): Min Pipe Cover (ft): Invert (ft): Rim (ft): Node ID:Inlet-01 371.25 367.15 SDMH-01 371.74 367.00 Link-04 0.0030 1.22 2.55 50.90 18.00 0.73 367.15 367.00 369.75 367.83 3.22 367.79 23-20001866 2/3/2025 APPENDIX D RETENTION BASIN VOLUME CALCULATIONS 23-20001866 2/3/2025 © 2023 Microsoft Corporation © 2023 Maxar ©CNES (2023) Distribution Airbus DS © 2023 TomTom Ó L:\Projects\2023\230035\ENGINEERING\Master Plan\T4734_hydro estimate.dwg, 12/13/2024 9:46:48 AM, _AutoCAD PDF (General Documentation).pc3 23-20001866 2/3/2025 Area 1 Land Use Type ai Area (sf)Area (ac)V (ac*ft) 1 R-2 0.55 2695993.46 61.89 5.11 2 Commercial 0.90 3884762.72 89.18 12.04 3 R-1 0.42 856519.30 19.66 1.24 4 R-1 0.42 2282786.50 52.41 3.30 5 Undeveloped 0.15 148104.00 3.40 0.08 Required Capacity 21.8 ac*ft Letzring R-3 0.9 268769.15 6.17 0.83 Required Capacity with Letzring 22.6 ac*ft Capacity per Survey (2' of freeboard)17.06 ac*ft Bottom Area (354.7 Contour):1.31AC Middle Area (360.1 Contour):2.17AC Top Area (365.5 Contour):2.90AC Basin Volume: (1/6)[Bottom Area+4(Middle Area)+Top Area]*Height (1/6)(1.31AC+4(2.17AC)+2.90AC]*10.8ft=23.20AC-ft City of Bakersfield Sump 48 White Huges V=0.15 ∗ܽ ∗ܣ This document was created by an application that isn’t licensed to use novaPDF. Purchase a license to generate PDF files without this notice. PROPOSED BASIN VOLUME 23-20001866 2/3/2025 Cut/Fill Summary Name 2ft Free Board Basin Vol. Totals Fill Factor 1.000 2d Area 187157.00 Sq. Ft. 187157.00 Sq. Ft. Fill 27515.41 Cu. Yd. 27515.41 Cu. Yd. Ó N 23-20001866 2/3/2025 Cut/Fill Summary Name 2ft Free Board Basin Vol. Totals Fill Factor 1.000 2d Area 127,425 Sq. Ft. 127,425 Sq. Ft. Fill 36,407 Cu. Yd. 36,407 Cu. Yd. Ó N 23-20001866 2/3/2025 APPENDIX E PROPOSED STORM DRAIN AND BASIN PLAN 23-20001866 2/3/2025 116122126116122126XXXXXXXXXXBUILDING P (TYPE 3)BUILDING R (TYPE 5) BUILDING A (TYPE 1)BUILDING B (TYPE 1) 8,912 SF B U I L D I NG C ( T Y P E 1 ) 8, 9 1 2 S F BUILDING N (TYPE 2) 5,092 SF BUILDING M (TYPE 2) 5,092 SF BUILDING L (TYPE 2) 5,092 SF B U I L D I NG D ( T Y P E 2 ) B U I L D I N G E ( T Y P E 2 ) B U I L D I NG F ( T Y P E 2 ) BUILDING G (TYPE 2)BUILDING H (TYPE 2)5,092 SFBUILDING J (TYPE 2)5,092 SFBUILDING K (TYPE 2)5,092 SFBUILDING Q (TYPE 4)5,092 SF6,939 SF376.10 FF3,325 SF 376.08FF 8,912 SF 376.0 FF 8,912 SF 375.6 FF 8, 9 1 2 S F 3 7 5 . 1 F F 5,092 SF 376.35 FF 5,092 SF 376.45 FF 5,092 SF 376.55 FF 5, 0 9 2 S F 3 7 6 . 6 5 F F 5, 0 9 2 S F 3 7 6 . 5 5 F F 5, 0 9 2 S F 3 7 6 . 6 6 F F 5,092 SF376.77 FF 5,092 SF377.23 FF5,092 SF377.11 FF5,092 SF377.03 FF9,363 SF376.05 FFKnow what'sbelow.before you dig.CallRWARNINGPOWERLINESOVERHEADPROJECT NO:22224-J-01LETZRINGSENIORHOUSING4215 LETZRING LN.AFFORDABLE HOUSINGBAKERSFIELD, CA 93304DRAWING SUBMITTAL SCHEDULEBUILDING PERMIT SUBMITTAL03/01/202413111 CAMINO DEL RIO NORTH,STUDIO 500SAN DIEGO, CA 92108619.297.0131WWW.SGPA.COM901 EAST MAIN STREETVISALIA, CA 93292559.733.0440QKSGPA 2023©HOUSINGAUTHORITY OFTHE COUNTY OFKERN601 24TH ST.BAKERSFIELD, CA 93301NOT FOR CONSTRUCT ION CITY OFBAKERSFIELDSTAMPNSHEET C-8STORM DRAIN PLAN23-200018662/3/2025 EXISTING BASIN N ÓL:\Projects\2023\230035\ACAD\Improvements\Off-Site\230035-TOPO.dwg, 8/29/2024 10:18:01 AM, _AutoCAD PDF (General Documentation).pc3 23-20001866 2/3/2025 PROPOSED BASIN N ÓSTAR JASMINE COURT ST HELENS AVE 23-20001866 2/3/2025 Ó23-20001866 2/3/2025 CURVE TABLE MATCHLINE STA 13+50SEE SHEET 8LETZRING LANE STA 10+00 - 13+50 N ÓFOXGLOVE COURT CALLA LILY DRIVE MATCHLINE STA 13+50SEE SHEET 823-20001866 2/3/2025 CURVE TABLE MATCHLINE STA 13+50SEE SHEET 7LETZRING LANE STA 13+50 - 19+00 NÓALLEY DRIVEWAYDRIVEWAY MATCHLINE STA 13+50SEE SHEET 723-20001866 2/3/2025 MATCHLINE STA 13+50SEE SHEET 10LETZRING LANE STA 10+00 - 13+50 N ÓFOXGLOVE COURT CALLA LILY DRIVE MATCHLINE STA 13+50SEE SHEET 823-20001866 2/3/2025 MATCHLINE STA 13+50SEE SHEET 9LETZRING LANE STA 13+50 - 19+00 NÓALLEY DRIVEWAYDRIVEWAY MATCHLINE STA 13+50SEE SHEET 723-20001866 2/3/2025 LETZRING LANE STA 10+09.96 ÓFOXGLOVE COURTLETZRING LANE LETZRING LANE LETZRING LANE LETZRING LANELETZRING SENIOR HOUSINGN N LETZRING LANE STA 11+42.01 23-20001866 2/3/2025 APPENDIX F AS-BUILT STORM DRAIN PLANS 23-20001866 2/3/2025 23-20001866 2/3/2025 sdmh rim=371.74 on qk datum ssmh rim =371.78 on qk datum monument is 370.95 SDMH-01 23-20001866 2/3/2025 SDMH-01 SDMH-02 23-20001866 2/3/2025 SSMH-03 SSMH-02 23-20001866 2/3/2025 150.51° 14.99 ft 24.56 ft5.77 ft82.88 f t 23-20001866 2/3/2025 APPENDIX G OFFSITE SUMP STUDY SLOPE ANALYSIS 23-20001866 2/3/2025 4400 YEAGER WAY Phone: 661 831 5100 info@soilsengineering.com BAKERSFIELD, CA 93313-2019 Fax: 661 831 2111 www.soilsengineering.com February 5, 2024 SEI File No. 23-19096 Housing Authority of the County of Kern 601 24th Street Bakersfield, CA 93301 Attention: Mr. Stephen M. Pelz Subject: Drainage Basin Investigation & Slope Stability Analysis Project: Letzring Senior Housing Offsite Drainage Basin Location: 35.313345, -119.028260 | Near Timber Mtn Wy & St. Helens Ave, Bakersfield, CA Reference [1]: Geotechnical Investigation Report Project: Letzring Senior Housing Location: 4215 Letzring Lane, Bakersfield, Kern County, CA SEI File No. 23-19096, Dated August 21, 2023 Dear Mr. Pelz: In accordance with your request, Soils Engineering, Inc. (SEI) has prepared this report, which details our findings from the field investigation conducted within the offsite sump. The proposed improvements will be to direct overflow water from the senior housing site to the offsite sump. The project is located at a preexisting sump, which is approximately 0.28 miles south of the Letzring Senior Housing project. The project site is northeast of the intersection of Timber Mountain Way & St. Helens Avenue, and bounded on all sides by residential housing tracts, save for the northwestern corner which looks onto railroad tracks. The basin has an approximately 5:1 slope with the toe at about 360’ in elevation. The sump is approximately 8 feet deep. FIELD INVESTIGATION Two (2) exploratory borings were drilled to a maximum depth of forty-one (41) feet below existing ground surface in the proposed drainage basin. The borings were advanced using an eight-inch diameter auger attached to a CME 75 drill rig. Earth materials encountered were logged, classified in accordance with the Unified Soils Classification System, and graphically presented on the Test Boring Logs (attached, Figures 2 and 3). Undisturbed soil samples of representative subsurface soils were obtained by driving a two and three-eighths (2-3/8) inch inside diameter split-barrel sampler in the soil layer in accordance with the Standard Test Method for Penetration Test and Split-Barrel Sampling of Soils (ASTM D1586). Penetration resistance of undisturbed soils was obtained by driving the above-described sampler using a 140-pound hammer falling a distance of 30 inches and recording blow counts for each six-inch increment of drive on Test Boring Logs. LABORATORY TESTING PROGRAM Undisturbed samples were retrieved during our drilling operation. # 200 washes were performed according to ASTM specifications D-1140, and results are shown on the document labeled as Figure A- 4. Direct Shear Tests were performed according to ASTM specifications D-3080, and results are shown on Figures C-3 and C-4. Permeability tests were performed in accordance with ASTM D2434 and the results are presented on Table 1. 23-20001866 2/3/2025 SOILS ENGINEERING, INC. Drainage Basin Investigation SEI File No. 23-19096 Project: Letzring Senior Housing Offsite Drainage Basin February 5, 2024 Location: 35.313345, -119.028260 | Near Timber Mtn Wy & St. Helens Ave, Bakersfield, CA Page 2 4400 YEAGER WAY Phone: 661 831 5100 info@soilsengineering.com BAKERSFIELD, CA 93313-2019 Fax: 661 831 2111 www.soilsengineering.com ENGINEERING REPORT Slope Stability Analysis: Slope stability analyses were performed for slopes with a depth up to 20 feet with 2:1 (H:V). The stability of the slope was analyzed for the static and pseudo-static condition. The horizontal ground motion site coefficient of 0.2 was used in the slope stability analysis. The slope stability analyses are presented in Figures A and B. The results of the critical factors of safety are presented in the following Table A: TABLE A CRITICAL FACTORS OF SAFETY MAXIMUM SLOPE HEIGHT – 15’ Maximum Slope (H:V) STATIC PSEUDO-STATIC 2 : 1 2.03 1.34 Based on our investigation and our analysis, there are no soil conditions that would preclude the construction of the proposed sump and the slopes are considered safe with safety factor greater than 1.5 for Static and 1.1 for Pseudo-Static. The subsurface soils, below the invert of the sump, consisted of cohesionless sandy soils classified as SP and SM, respectively, in the Unified Soils Classification System (USCS). Drainage: Based on the soil conditions encountered, the existing sump should drain in 7 days or less, provided the upper 6 inches of silt/sediments at the bottom of the sump is removed. Annual removal of silt buildup at the bottom of the sump should be performed to maintain effective drainage. We appreciate the opportunity to be of service and hope this provides the information you require. Please contact our office should you have any questions or if we can be of further assistance. Respectfully Submitted, SOILS ENGINEERING, INC. On Man Lau, P.E., G.E. Engineering Manager Attachments: Boring Location Map, Figure 1 Boring Logs, Figures 2 and 3 Slope Stability Analyses, Figures A and B Laboratory Testing Data Summary, Table 1 Sieve Analyses, Figure A-4, Direct Shear, Figures C-3 and C-4 © 2024 SOILS ENGINEERING, INC. 23-20001866 2/3/2025 B-1B-2Boring Location Map Figure 1 SEI File No. 23-1909623-200018662/3/2025 0 4 8 12 16 20 24 28 17/6 22/6 34/6 13/6 24/6 31/6 7/6 11/6 16/6 13/6 21/6 28/6 14/6 23/6 31/6 8/6 12/6 18/6 SM SP SM SILTY SAND; light yellowish brown, damp, poorly graded, cohesive. Dense. POORLY GRADED SAND; light yellowish brown, damp, fine to medium grained. Medium dense. Dense. SILTY SAND; light yellowish brown, moist, fine, cohesive, traces of clay. Medium dense. 120.0 118.2 96.7 95.6 98.8 102.5 2.7 1.7 3.1 3.4 4.5 24.4 SOILS ENGINEERING, INC. LOG OF TEST BORING BORING B-1A PROJECT:Letzring Senior Housing FILE NO:19096 BORING DATE:1/17/24 ELEV.:Approx. 355' BORING LOCATION:See Boring Location Map, Figure 1 START:1/17/24 DRILL METHOD:4.25" I.D. Hollow-Stem Auger FINISH:1/17/24 DESCRIPTION:Geotechnical Engineering Services DEPTH TO WATER -:N/A CAVING -:N/A LOGGER:LW Figure Number 2 ELEVATION/ DEPTH (feet) SOIL SYMBOLS SAMPLER SYMBOLS AND FIELD TEST DATA USCS Description Remarks Density pcf Moisture % Page 1 of 2 23-20001866 2/3/2025 32 36 40 44 48 52 56 16/6 28/6 38/6 19/6 27/6 38/6 11/6 32/6 36/6 SP SM SP POORLY GRADED SAND; light yellowish brown, moist, fine to medium grained. Dense. SILTY SAND; yellowish brown, moist, fine to medium grained, cohesive, traces of clay. POORLY GRADED SAND; light yellowish brown, moist, fine to medium grained. BOTTOM. 103.1 97.2 101.2 4.7 5.2 4.7 SOILS ENGINEERING, INC. LOG OF TEST BORING BORING B-1A PROJECT:Letzring Senior Housing FILE NO:19096 BORING DATE:1/17/24 ELEV.:Approx. 355' BORING LOCATION:See Boring Location Map, Figure 1 START:1/17/24 DRILL METHOD:4.25" I.D. Hollow-Stem Auger FINISH:1/17/24 DESCRIPTION:Geotechnical Engineering Services DEPTH TO WATER -:N/A CAVING -:N/A LOGGER:LW Figure Number 2 ELEVATION/ DEPTH (feet) SOIL SYMBOLS SAMPLER SYMBOLS AND FIELD TEST DATA USCS Description Remarks Density pcf Moisture % Page 2 of 2 23-20001866 2/3/2025 0 4 8 12 16 20 24 28 8/6 10/6 10/6 9/6 14/6 17/6 10/6 14/6 17/6 8/6 15/6 20/6 8/6 14/6 17/6 7/6 23/6 34/6 SM SC SP- SM SILTY SAND; light brown, damp, poorly graded, cohesive. Medium dense. CLAYEY SAND; light yellowish brown, damp, poorly graded, cohesive. POORLY GRADED SAND with low fine content; light yellowish brown, damp, fine to meidum grained. Dense. 103.6 108.9 113.2 95.2 116.5 102.2 4.4 3.1 6.1 3.4 3.5 1.8 SOILS ENGINEERING, INC. LOG OF TEST BORING BORING B-2A PROJECT:Letzring Senior Housing FILE NO:19096 BORING DATE:1/17/24 ELEV.:Approx. 355' BORING LOCATION:See Boring Location Map, Figure 1 START:1/17/24 DRILL METHOD:4.25" I.D. Hollow-Stem Auger FINISH:1/17/24 DESCRIPTION:Geotechnical Engineering Services DEPTH TO WATER -:N/A CAVING -:N/A LOGGER:LW Figure Number 3 ELEVATION/ DEPTH (feet) SOIL SYMBOLS SAMPLER SYMBOLS AND FIELD TEST DATA USCS Description Remarks Density pcf Moisture % Page 1 of 2 23-20001866 2/3/2025 32 36 40 44 48 52 56 12/6 29/6 27/6 6/6 23/6 17/6 16/6 18/6 21/6 CL SM Traces of clay, dense. SANDY CLAY; olive brown, moist, low to medium plasticity. Very stiff. SILTY SAND; yellowish brown, moist, fine, cohesive, traces of clay. Medium dense. BOTTOM. 111.4 89.5 108.0 6.3 23.5 22.8 SOILS ENGINEERING, INC. LOG OF TEST BORING BORING B-2A PROJECT:Letzring Senior Housing FILE NO:19096 BORING DATE:1/17/24 ELEV.:Approx. 355' BORING LOCATION:See Boring Location Map, Figure 1 START:1/17/24 DRILL METHOD:4.25" I.D. Hollow-Stem Auger FINISH:1/17/24 DESCRIPTION:Geotechnical Engineering Services DEPTH TO WATER -:N/A CAVING -:N/A LOGGER:LW Figure Number 3 ELEVATION/ DEPTH (feet) SOIL SYMBOLS SAMPLER SYMBOLS AND FIELD TEST DATA USCS Description Remarks Density pcf Moisture % Page 2 of 2 23-20001866 2/3/2025 1. Two (2) exploratory borings were drilled on 01/17/2024 using an 8-inch outside diameter hollow-stem auger. 2. No free groundwater was encountered to the maximum depth drilled of 41.5'. 3. Boring locations are shown on the Boring Location Map, Figure 1. 4. These logs are subject to the limitations, conclusions, and recommendations in this report. 5. Results of tests conducted on samples recovered are reported on the logs. Notes: Symbol Description Strata symbols Silty sand Poorly graded sand Clayey sand Poorly graded sand with silt Low plasticity clay Misc. Symbols Boring continues Soil Samplers California sampler KEY TO SYMBOLS 23-20001866 2/3/2025 Figure A 23-200018662/3/2025 Figure B 23-200018662/3/2025 CCCSHV % C, (ksf) F.A.QU, (ksf)C, (ksf) R.V. E.P. (psi)B-1A @ 6' SM 253.56 x 10-5B-1A @ 11' SP 3.12.75 x 10-2B-1A @ 16' SP 2.42.12 x 10-2B-2A @ 6' SM 26 0.19 32.4B-2A @ 16' SP-SM 6.0 0 37.8CONSTANT HEAD PERMEABILITY K - Coefficient of Permeability (cm/sec) CONSOLIDATION Cc - Compression Index Cs - Swell Index S.P. (pcf) - Swell Pressure HV % - Heave Precentage / Collapase (R)ESISTANCE VALUE RV - R-Value @ 300 psi EV - Expansion Press @ 300 psiS.G.USCSDIRECT SHEAR C (ksf) - Cohesion F.A. - Friction Angle S.G. - Specfic GravityR-VALUE @ 300 psi SEI File No. 23-19096Geotechnical Engineering Services4215 Letzring Lane, Bakersfield, CA 93304February 2, 2024Letzring Senior HousingHousing Authority of the County of KernKPERM.% < # 200CONSOLIDATION UNCONFINED COMPRESSIONE.I.TABLE 1E.I. - EXPANSION INDEX UNCONFINED COMPRESSION QU (ksf) - Unconfined Compression Strength C, (ksf) - Cohesion S.P. (pcf)TEST LOCATIONDIRECT SHEAR© 2024 SOILS ENGINEERING, INC.23-200018662/3/2025 SOILS ENGINEERING, INC. Client: Project: Project No.:Figure Housing Authority of the County of Kern Letzring Senior Housing 19096 A-4 SYMBOL SOURCE SAMPLE DEPTH Material Description USCSNO.(ft.) SOIL DATAPERCENT FINER0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 25.2 3.1 2.4 26.2 6.03 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report B-1A 6'SILTY SAND SM B-1A 11'POORLY GRADED SAND SP B-1A 16'POORLY GRADED SAND SP B-2A 6'SILTY SAND SM B-2A 16'POORLY GRADED SAND with low fine conntent SP-SM 23-20001866 2/3/2025 Tested By: SC Checked By: AL DIRECT SHEAR TEST REPORT SOILS ENGINEERING, INC. Client: Housing Authority of the County of Kern Project: Letzring Senior Housing Source of Sample: B-2A Depth: 6' Proj. No.: 19096 Date Sampled: 01/17/24 Sample Type: 2.50" x 6" TUBE Description: SILTY SAND; light brown, damp, poorly graded, cohesive. LL= N/A PI= N/A Assumed Specific Gravity= 2.65 Remarks:Test Date: 01/25/24 Figure C-3 Sample No. Water Content, % Dry Density, pcf Saturation, % Void Ratio Diameter, in. Height, in. Water Content, % Dry Density, pcf Saturation, % Void Ratio Diameter, in. Height, in. Normal Stress, ksf Fail. Stress, ksf Displacement, in. Ult. Stress, ksf Displacement, in. Strain rate, in./min.InitialAt TestShear Stress, ksf0 0.5 1 1.5 2 2.5 3 Horiz. Displacement, in. 0 0.1 0.2 0.3 0.4 1 2 3Vertical Deformation, in.0.015 0.01 0.005 0 -0.005 -0.01 -0.015 Horiz. Displacement, in. 0 0.1 0.2 0.3 0.4 Dilation Consol. 1 2 3 Fail. Stress, ksf0 2 4 6 Normal Stress, ksf 0 2 4 6 C, ksf f, deg Tan(f) Results 0.19 32.4 0.64 1 4.8 100.4 19.6 0.6485 2.38 1.00 22.2 100.4 90.7 0.6485 2.38 1.00 1.00 0.80 0.18 N/A 2 5.7 98.5 22.1 0.6787 2.38 1.00 20.6 98.5 80.4 0.6787 2.38 1.00 2.00 1.48 0.15 N/A 3 5.9 98.6 23.2 0.6773 2.38 1.00 20.3 98.6 79.5 0.6773 2.38 1.00 4.00 2.72 0.21 N/A 23-20001866 2/3/2025 Tested By: SC Checked By: AL DIRECT SHEAR TEST REPORT SOILS ENGINEERING, INC. Client: Housing Authority of the County of Kern Project: Letzring Senior Housing Source of Sample: B-2A Depth: 16' Proj. No.: 19096 Date Sampled: 01/17/24 Sample Type: 2.50" x 6" TUBE Description: POORLY GRADED SAND with low fine content; light yellowish brown, damp, fine to LL= N/A PI= N/A Assumed Specific Gravity= 2.65 Remarks:Test Date: 01/25/24 Figure C-4 Sample No. Water Content, % Dry Density, pcf Saturation, % Void Ratio Diameter, in. Height, in. Water Content, % Dry Density, pcf Saturation, % Void Ratio Diameter, in. Height, in. Normal Stress, ksf Fail. Stress, ksf Displacement, in. Ult. Stress, ksf Displacement, in. Strain rate, in./min.InitialAt TestShear Stress, ksf0 1 2 3 4 5 6 Horiz. Displacement, in. 0 0.1 0.2 0.3 0.4 1 2 3Vertical Deformation, in.0.03 0.02 0.01 0 -0.01 -0.02 -0.03 Horiz. Displacement, in. 0 0.1 0.2 0.3 0.4 Dilation Consol. 1 2 3 Fail. Stress, ksf0 2 4 6 Normal Stress, ksf 0 2 4 6 C, ksf f, deg Tan(f) Results 0 37.8 0.78 1 5.2 98.8 20.5 0.6743 2.38 1.00 22.0 98.8 86.5 0.6743 2.38 1.00 1.00 0.74 0.11 N/A 2 5.6 97.8 21.6 0.6920 2.38 1.00 19.9 97.8 76.1 0.6920 2.38 1.00 2.00 1.61 0.12 N/A 3 5.8 97.2 21.7 0.7025 2.38 1.00 20.1 97.2 75.8 0.7025 2.38 1.00 4.00 3.09 0.36 N/A 23-20001866 2/3/2025