Headquarters North Bay Office East Bay Office South Bay Office 150 Executive Park Blvd, Ste 4200 505 San Marin Dr, Ste A220 1101 Marina Village Pkwy, Ste 104 20863 Stevens Creek Blvd, Ste 400 San Francisco, CA 94134 Novato, CA 94945 Alameda, CA 94501 Cupertino, CA 95014 (415) 534-7070 (415) 534-7070 (510) 937-2310 (408) 516-1090 Memorandum
Re: El Camino Real Dewatering Project
Date: August 22, 2025
To: Robert Ovadia, P.E., Town of Atherton DPW Director
From: Eric Biland, P.E., QSD/P, LEED AP, Senior Project Manager Freyer & Laureta, Inc. (F&L) is pleased to submit this Technical Memorandum (Memo) to the Town of Atherton (the Town) to address flooding issues along the El Camino Real Corridor (ECR) within the Town.
Storm events regularly cause flooding along the ECR Corridor, particularly at intersections, as documented in the "Town of Atherton Townwide Drainage Study Update" (April 2015) (the Study) and observed in the field with this study.
This Memo outlines solutions to flooding events along the ECR Corridor within the Selby Lane and ECR drainage areas. Improvement development utilized the following:
• a topographic study (including surface information) provided by the Town on October 5, 2024; • field information collected on December 5 and 14, 2024; Additional field information to verify existing catch basins and flooding was collected by F&L on January 22 and February 04, 2025 (see Appendix 2 for photos) • utility maps from West Bay Sanitary District, Fair Oaks Sewer Maintenance District, PG&E, Comcast, Cal Water, and AT&T;
• as-builts from Caltrans and the Town of Atherton;
• the ECR Complete Streets Gap Closure Study (under development by the Town as of 2025). • "Town of Atherton Townwide Drainage Study Update" (April 2015) (the Study) • Bess Utility Report (July 1, 2025) and CCTV footage (June 26, 2025) This Memo also details proposed solutions to mitigate extensive flooding events along ECR from Selby Lane to Isabella Ave. The proposed solutions consist of a combination of point and a dewatering system along the east side of ECR. See Appendix 5 and Appendix 5A for proposed dewatering project plans. 1 BACKGROUND
The Town's drainage infrastructure includes traditional storm drains, developed channels, and dry pits for storm flow percolation.
The Town is divided into 4 main drainage areas (see Appendix 1). Currently, ECR lacks a developed piped drainage system for the stormwater runoff from the western drainage areas, relying mainly on ditches, culverts and overland flow to convey runoff.
ATTACHMENT 3
FREYER & LAURETA, INC. Civil Engineers · Surveyors · Construction Managers 2 Storm events routinely cause flooding along ECR Corridor, creating safety issues particularly along the westside of intersections. This information is detailed in the Townwide Drainage Study. The majority of the flooding on the west side of ECR is due to the local topography, low spots along the west side of ECR, and the high crown in ECR. There is significantly less stormwater runoff on the east side of ECR. Flows are eventually conveyed to the existing storm drain elements in Redwood City and unincorporated San Mateo County. Drainage areas are shown in Appendix 1. Existing conditions and reported flooding are shown in Appendix 2 Runoff from the Selby Lane drainage area is conveyed overland to the west side of ECR where it floods the intersection. Runoff from this drainage area is eventually conveyed to the Redwood City stormdrain system via surface features.
A 42” Reinforced Concrete Pipe (RCP) storm drain segment starts at a catch basin at the intersection of Selby Lane and ECR. It crosses ECR but it is capped immediately past the Caltrans Right of Way on the east side. Currently, stormwater flows fill the 42” RCP through the catch basin on the west side of ECR and then slowly dissipate through the joints and end condition. Since there is no existing developed stormdrain system immediately on the east side of ECR, the 42” RCP is not a useful element for stormwater conveyance or detention and should be sealed off from any future dewatering improvements. Ground Penetration Radar (GPR) was conducted at the intersection of Selby Lane and ECR. See field observations and 42” RCP As-built in Appendix 2A.
On the South of Isabella Ave, runoff from the Atherton Channel drainage area is conveyed by a 36” RCP storm drain running along the west side of ECR and discharges into Atherton Channel near the Isabella Ave. and ECR intersection.
Proposed flooding mitigation solutions combine point improvements (primarily along the east side of ECR) and a dewatering system along the west side of ECR. The overall dewatering system is designed to reduce the amount of surface flooding and assist in the operation of future bioretention areas proposed in the ECR corridor improvements. 2 ALTERNATIVES
The alternatives to the localized flooding along ECR considered various criteria, including existing drainage patterns, existing storm infrastructure, cost considerations, constructability constraints, and the integration of storm drain system improvements with future road improvements.
The following alternatives were evaluated based on the aforementioned criteria:
2.1 Alternative 1: Regrading
This solution focuses on regrading intersections and ditches along ECR. Field observations have identified depressions that would create unacceptable stormwater spread along the ECR. Implementing this alternative would also necessitate an extensive and costly regrading project along the entire length of ECR.
2.2 Alternative 2: A Dewatering System Consisting Of One New Storm Drain Alignment And One Lift Station
This alternative proposes a dewatering system utilizing a single new storm drain alignment, starting at Stockbridge Ave. and conveying ponded stormwater to the Atherton Channel via a lift station at Isabella Avenue. A dewatering system combines ground surface and underground pipelines to drain puddled water in concentrated areas to a working stormdrain system. As a result, a dewatering system is most beneficial as it reduces the overflow in puddling areas. For this alternative, significant pipe depths would be required at Isabella Avenue due to the alignment's trajectory against the existing ground slope. Constructability considerations, specifically maintaining a wet well depth below 30 feet, a minimum storm drain slope of 0.1%, and a minimum cover of 3 feet at the alignment's origin, limit FREYER & LAURETA, INC. Civil Engineers · Surveyors · Construction Managers 3 the alignment's starting point to Stockbridge Avenue. This alignment would consist of approximately 4,200 linear feet (LF) of 12-inch HDPE pipe with depths ranging from 4 ft. to 27 ft.
2.3 Alternative 3: A Dewatering System Consisting Of Two New Storm Drain Alignments And Two New Lift Stations
This Alternative proposes two segments to address the flooding at intersections along ECR.
Segment 1 begins at Stockbridge Avenue and extends north along the east side of ECR to a proposed lift station at Selby Lane. This segment consists of 1,260 LF of 12” HDPE SDR 26 gravity line, 420 LF of 6” HDPE laterals, and drains stormwater from Stockbridge Avenue and Selby Lane. The collected stormwater is then pumped from a lift station at Selby Lane to a discharge structure that releases overland flows towards Redwood City via the paved curb and gutter that starts approximately 130 feet south of Renato Court.
This design aims to maintain the existing drainage pattern, where runoff from the Selby Lane drainage area flows towards Redwood City.
Segment 2 starts at Almendral Ave. It includes approximately 3,144 LF of 12” HDPE gravity line, 87 LF of 10” HDPE, 92 LF of 8” HDPE, and collects stormwater along the west side of ECR to a new lift station at Isabella Avenue. The collected stormwater would be pumped to an intermediate structure that will drain via gravity into the Atherton Channel through a 12” HDPE pipe. A level float within the intermediate manhole will signal the pumps to stop before the water level in the Atherton Channel reaches its peak capacity, avoiding any impact to the Channel’s flood capacity. Dewatering resumes once the Atherton Channel has excess capacity.
There will be no stormwater segments between Stockbridge Ave and Almendral Ave. Existing grades in this area permits flow to either Stockbridge Ave or Almendral Ave where stormwater will drain to Segment 1 or 2, respectively.
For budgeting purposes, the Alignments proposed in Alternative 3 can be constructed separately in two phases. 3 DESIGN CRITERIA
Alternatives 2 and 3 consist of new pipe segments installed through Horizontal Direction Drilling (HDD), that convey stormwater via gravity and pumped systems. The proposed improvements are described in Section 4.
3.1 Pipe Alignments
Pipe segments are designed as 12” HDPE gravity lines along ECR, with a minimum slope of 0.1%. Laterals include 6”, 8”, and 10” HDPE pipes.
The pipes are sized at 6”-12” to minimize the stormwater volume stored within the system and maximize the drawdown of surface flooding. The 12” pipe size was selected to enhance constructability while providing a pipe diameter sufficient for cleaning purposes and maintaining a suitable drainage velocity.
Drain inlets (DI), either drop inlets or catch basins, measuring 12” x 12”, were added in areas where flooding was observed at lateral street intersections within ECR. These drain inlets connect to the main pipe segment along the ECR Corridor via 12” laterals. The drain inlets would be equipped with trash capture inserts. These inserts, in conjunction with the low drainage velocity, are designed to control the amount of debris and silts that reach the lift stations.
FREYER & LAURETA, INC. Civil Engineers · Surveyors · Construction Managers 4 All proposed pipes, both main line and laterals, have a minimum cover of 4 feet, with depths ranging from 4 ft to 17 ft.
The vertical clearance between the proposed utilities and existing utilities ranges from approximately 0.5 ft to 7.24 ft.
The location for the main 12” pipe corridor was selected based on anticipated future ECR improvements. The proposed gravity pipeline is designed to be located beneath the proposed future bike lane. Appendix 3 illustrates proposed pipe segments in relation to the road improvement options considered by the Town. Additionally, the proposed segments are located such that they can accommodate future tie-ins for bioretention areas.
3.2 Lift Stations
Lift stations are designed as duplex pump systems. To minimize individual pump size, both pumps in each of the lift stations can operate simultaneously to achieve the maximum dewatering flow.
Both Lift Stations will require a PG&E service meter and can be equipped with Supervisory Control and Data Acquisition (SCADA) technology to facilitate operations and maintenance.
Flow rate calculations
Flow rate determination relies on the total estimated drainage volume after storm subsidence and the desired drainage time.
The estimated volume lifted by the stations comprises of two components: stored volume and ponded volume. • Stored volume represents water detained within each dewatering systems, encompassing the 12” HDPE main trunk pipe, DIs and associated laterals, the wet well, and manholes. • Ponded volume estimation utilizes AutoCAD Watershed Analysis. The methodology and the results are presented in Appendix 4.
Flows and velocities have been calculated based on the total volume and various dewatering times. Lower velocities within the dewatering system are preferred to facilitate trash/silt settlement before the lift station. 4 PROPOSED IMPROVEMENTS
This section describes design considerations specific to each pipe segment and proposed Point Solutions. For Plan and Profile of the pipe segments, see Appendix 5 and Appendix 5A.
4.1 Proposed Alignments And Lift Stations
4.1.1 Alignment 1 – Selby Lane Lift Station
Segment 1 dewaters flooding between Stockbridge Ave. and Selby Lane.
It consists of approx. 1,260 LF of 12” HDPE at 0.1% slope and 420 LF of 6” HDPE laterals at varying slopes, with invert depths ranging from 4 ft. to 9ft., 4 Catch Basins with associated 12” laterals and a lift station described below.
The lift station at Selby Lane consists of a 4’ diameter, 6ft. - deep wet well with a duplex system of 2 identical Flygt NP3069 model at 2.4 HP each. The pump discharge through a 6” pipeline to a traffic-rated pop-up emitter installed 335ft. north of the intersection of Selby Rd along ECR. From here, the stormwater is conveyed overland through its established drainage pattern to Redwood Creek. For this application, the pumping system is mostly effective when operated at 500 Gallons Per Minute (gpm) at a head of 10ft. Total Dynamic Head (TDH) (See Appendix 6 for Pump Curve).
FREYER & LAURETA, INC. Civil Engineers · Surveyors · Construction Managers 5 The total volume processed by the lift station at Selby Lane is summarized in Table 1.
Table 1: Total Volume and Drainage Velocity at Selby Lane Lift Station Volume (Gallons)
Stored Volume
Catch Basins (Note 1) 200
Wet Well (Note 2) 1,500
Pipe (Note 3) 7,570
Manholes (Note 4) 2,400
Ponded Volume Selby Lane (Note 5) 700
Stockbridge Ave. (Note 6) 2,500
Total Volume 14,870
Drainage Flow (gpm) (Note 7) 500
Velocity (ft/s) (Note 7) 1.49
Notes
1 4 (four) 12"X12" Catch Basin structures, average depth = 4ft. 2 Diameter 4’ and 4ft water depth
3 1,260 LF 12" HDPE SDR 26, including 420 LF 6” HDPE laterals 4 4 (four) MH diameter 4’, 6ft depth of water
5 Volume estimated through AutoCAD Watershed Analysis
6 Reported Flooding #99, #8 (Appendix 2). Flooding Volume estimate using AutoCAD Watershed Analysis (Appendix 4).
7 Drainage Flow and Velocity are estimated based on calculated total volume and 30 minutes dewatering time.
4.1.2 Alignment 2 - Isabella Ave. Lift Station
Segment 2 dewaters flooding at intersections south of Almendral Ave.
It consists of approx. 3,144 LF of 12” HDPE at 0.1% slope, and 8”-10” HDPE laterals totaling 179 LF, with invert depths ranging from 4 ft. to 21ft., 12 DI’s/Catch Basins and a lift station described below.
The lift station at Isabella Ave. is a 17 ft. deep 6’ diameter wet well, duplex pumping system with 2 identical Flygt NP3102 LT 3-phase 5HP. The pumping system’s duty point is 650 gpm at 25 ft. TDH (see Appendix 7 for Pump Curve).
It has a discharge pipeline of 8” to an intermediate manhole before discharging by gravity to the Atherton Channel.
Pumps are controlled by a transducer located in the wet well, as well as by a level sensor installed in the intermediate manhole. This level float would be set at the same hydraulic grade as the Atherton Channel running at full capacity and it will signal the pumps to stop during Atherton Channel peak flow, ensuring that the dewatering system is not overwhelming the Channel’s capacity. The pumps will remain off until the level in the Atherton Channel subsides to allow for available Channel capacity before resuming the dewatering process.
The total volume processed by the lift station at Isabella Ave. is summarized in Table 2.
FREYER & LAURETA, INC. Civil Engineers · Surveyors · Construction Managers 6 Table 2: Total Volume and Drainage Velocity at Isabella Ave. Lift Station Volume (Gallons)
Stored Volume
Dis/Catch Basin (Note 1) 600
Wet Well (Note 2) 2,000
Pipe (Note 3) 18,170
Manholes (Note 4) 6,200
Ponded Volume
Almendral Ave.(Note 5) 750
372 CA-82 (Note 6) 750
Isabella Ave. (Note 7) 750
Total Volume 29,220
Drainage Flow (gpm) (Note 8) 650
Velocity (ft/s) (Note 8) 1.92
Notes
1 6 (Six) 12"X12" DI structures and 6(Six) 12”x12” Catch Basin Structures, average depth = 4ft. 2 Diameter 6’ and 11ft water depth
3 3,144 LF 12" HDPE SDR 26, including 92 LF 8” HDPE and 87 LF 10” HDPE laterals 4 11 (eleven) MH diameter 4’, 6ft depth of water average 5 Reported Flooding #89, Flooding Volume Estimate using AutoCAD Watershed Analysis (Appendix 4). 6 Reported Flooding #101, Flooding Volume Estimated using AutoCAD WaterShed Analysis (Appendix 4). 7 Reported Flooding #110, Flooding Volume Estimated using AutoCAD Watershed Analysis (Appendix 4). 8 Drainage Flow and Velocity are estimated based on calculated total volume and 45 minutes dewatering time.
9 Volume totals are rounded up to the nearest 10.
4.2 Point Improvements
For the proposed location and conceptual detail, see Appendix 5 and Appendix 5A. All reported flooding number are referred from the Appendix 2.
From field visits and research, F&L proposes the following improvements to the flooding locations:
Observed Flooding at Selby Lane: STA 6+50.00
• Install a new valley gutter to convey runoff to proposed catch basin.
Reported Flooding #25: 208 CA-82, Atherton, CA 94027, STA: 16+00.00 • Pavement elevation at bus station concrete pad is too high causing water to collect in the surrounding area.
Pavement to be regraded.
Reported Flooding #99: Curb entrance at Stockbridge Ave from ECR, STA: 19+00.00 • Regrade existing valley gutter. Stormwater to be conveyed to Selby Lane proposed Lift Station.
Reported Flooding #8: Intersection at ECR and Stockbridge Ave., STA: 19+00.00 FREYER & LAURETA, INC. Civil Engineers · Surveyors · Construction Managers 7 • Pavement has depression and will be regraded to allow for overland flow.
Reported Flooding #89: Intersection at ECR and Almendral Ave.,STA: 29+57.72 • Pavement has depression. Pavement at the intersection and gutter to be regraded. Stormwater to be conveyed to Isabella Ave. proposed Lift Station.
Reported Flooding #101: Private Driveway, 372 CA-82 STA: 34+40.61 • Flooding at the two exits of the existing 12” culverts crossing ECR to Lloyden Court. A catch basin was added to drain flooding through segment 2 dewatering system.
Reported Flooding #78: Entrance at 385 Lloyden Park Lane, STA: 33+96.46 • The two existing 12-inch culverts outfalling at the entrance of 385 Lloyden Park Lane, which release water collected from the southbound side of ECR, will have a manhole and a catch basin installed on the southbound side of the culvert (opposite the existing outfall pipe). This modification will allow stormwater to be diverted into the proposed 12-inch HDPE storm drain pipe.
Reported Flooding #15: Entrance at Lloyden Park Lane from Lloyden Dr., STA: 34+97.46 • Valley gutter to be added at the entrance of Lloyden Park Lane to allow runoff to flow north of ECR.
Reported Flooding #113: Curb entrance at Fair Oaks Lane from ECR, STA: 46+24.37 • Regrade gutter to allow runoff to flow overland.
Reported Flooding #110: Intersection at ECR and Isabella Ave, STA: 58+50.00 • Existing gutter to be regraded on the south side of the interspection to direct flow into the new catchbasin. • Pavement has depression and will be regraded to allow for overland flow on the North Side.
Reported Flooding #28: ECR., STA: 80+75.00
• Existing ditch has depression and will be regraded to allow for overland flow. 5 ENGINEER’S ESTIMATE
This section outlines the total costs for both pipe segments described in Section 4, covering design, permitting, construction, and construction management. The Town should also consider ongoing maintenance expenses, such as pump servicing, pipe cleaning, and drain inlet insert replacement. Maintenance costs are not included in the Memo.
List of Expected Maintenance:
• Vactor Service
• Debris removal from Drop Inlets
• Wet Well cleaning/maintenance
• Valve pit cleaning/maintenance
5.1 Engineer’s Estimate – Alignment 1 (Selby Lane Lift Station) Item No Item Unit Quantity Unit Price Total Cost
1 F&L Design Cost LS 1 $ 170,000 $ 170,000
Permitting (Note 1) $ 30,000
2 Caltrans LS 1 $ - $ -
3 PG&E LS 1 $ 30,000 $ 30,000
FREYER & LAURETA, INC. Civil Engineers · Surveyors · Construction Managers 8 4 Fish and Wildlife LS 1 $ - $ -
Environmental $ 110,000
5 Environmental Review and CEQA Processing LS 1 $ 35,000 $ 35,000 6 Construction Cost (Note 2) LS 1 $ 1,055,200 $ 1,055,200 7 Construction Management Costs (Note 3) LS 1 $ 158,300 $ 158,300 Total $ 1,448,500
Notes:
1. Anticipated permitting for Selby Lane Lift Station include Caltrans ROW encroachment and new PG&E service for the Lift Station equipment. Caltrans waives permitting fees between agencies.
2. A detailed Engineer’s Estimate for the Construction Cost for Selby Lane Lift Station alignment can be found in Appendix 8A.
3. Construction Management Cost are estimated to 15% of the total Construction Cost (line Item 6).
5.2 Engineer’s Estimate – Alignment 2 (Isabella Ave. Lift Station) Item No Item Unit Quantity Unit Price Total Cost
1 F&L Design Cost LS 1 $ 170,000 $ 170,000
Permitting (Note 1) $ 80,000
2 Caltrans LS 1 $ - $ -
3 PG&E LS 1 $ 30,000 $ 30,000
4 Fish and Wildlife LS 1 $ 50,000 $ 50,000
Environmental $ 110,000
5 Environmental Review and CEQA Processing LS 1 $ 35,000 $ 35,000 6 Construction Cost (Note 2) LS 1 $ 3,622,000 $ 3,662,000 7 Construction Management Costs (Note 3) LS 1 $ 543,300 $ 549,300 Total $ 4,496,300
Notes:
1. Anticipated permitting for Isabella Lane Lift Station include Caltrans ROW encroachment, new PG&E service for the Lift Station equipment and permitting for new outfall into Atherton Creek. Caltrans waives permitting fees between agencies.
2. A detailed Engineer’s Estimate for the Construction Cost for Selby Lane Lift Station alignment can be found in Appendix 8B.
3. Construction Management Cost are estimated to 15% of the total Construction Cost (line Item 6) CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com
CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com
CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com
CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com
CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com
CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com
CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com
PONDING VOLUME METHODOLOGY AND RESULTS
Ponded volume estimation utilizes AutoCAD Watershed Analysis to define watersheds based on the provided surface.
Depression-type watersheds on the south-bound (SB) side of El Camino Real between Selby Ave. and Isabella Ave. are identified, along with their lowest points and any associated draining or conveyance structures. Watersheds lacking drainage structures at their lowest points undergo further analysis. This analysis extracts the edge of each considered watershed and determines the lowest point on each depression's edge, defining the “spill-over” point where water drains into adjacent surface areas. Within each watershed, the contour matching the “spill-over” point elevation is identified, and the ponding volume is calculated from the watershed's lowest point to this contour using a conic approximation volume calculation method.
This methodology identified significant ponding (deeper than 4” and covering an area encroaching into the right of way) at several locations, as detailed in the following tables and exhibit.
The identified locations correspond to observed floods, as reported by residents and documented by F&L during the 12.14.2024 field visit (Appendix 2).
CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com Feet 0 40 80
Selby Lane Observed Ponding - 1
Project: El Camino Real Dewatering ProjectBasin Description: Selby LaneContour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (ft) Volume Volume Volume Volume (sq. ft) Avg. End Avg. End Conic Conic (cu. ft) (cu. ft) (cu. ft) (cu. ft)
36.60 0.25 N/A N/A 0.00 N/A 0.0036.62 2.52 0.02 0.03 0.03 0.02 0.0236.64 0.00 0.02 0.03 0.05 0.02 0.0436.64 12.70 0.00 0.00 0.05 0.00 0.0436.66 4.74 0.02 0.17 0.23 0.17 0.2136.66 40.06 0.00 0.00 0.23 0.00 0.2136.68 12.52 0.02 0.53 0.75 0.50 0.7136.68 79.35 0.00 0.00 0.75 0.00 0.7136.70 138.05 0.02 2.17 2.93 2.15 2.8636.72 189.02 0.02 3.27 6.20 3.26 6.1136.74 228.93 0.02 4.18 10.38 4.17 10.2936.76 0.51 0.02 2.29 12.67 1.60 11.8936.76 264.71 0.00 0.00 12.67 0.00 11.8936.78 0.38 0.02 2.65 15.32 1.83 13.7236.78 318.33 0.00 0.00 15.32 0.00 13.7236.80 0.24 0.02 3.19 18.51 2.18 15.9036.80 375.44 0.00 0.00 18.51 0.00 15.9036.82 434.69 0.02 8.10 26.61 8.09 24.0036.84 0.42 0.02 4.35 30.96 2.99 26.9936.84 494.75 0.00 0.00 30.96 0.00 26.9936.86 2.98 0.02 4.98 35.94 3.57 30.5636.86 558.15 0.00 0.00 35.94 0.00 30.5636.88 7.87 0.02 5.66 41.60 4.22 34.7836.88 626.90 0.00 0.00 41.60 0.00 34.7836.90 715.34 0.02 13.42 55.02 13.41 48.19 Selby Ln. Observed Ponding (2)
Project: El Camino Real Dewatering ProjectBasin Description: Selby Ln. Contour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (ft) Volume Volume Volume Volume (sq. ft) Avg. End Avg. End Conic Conic (cu. ft) (cu. ft) (cu. ft) (cu. ft)
36.52 0.03 N/A N/A 0.00 N/A 0.0036.54 0.16 0.02 0.00 0.00 0.00 0.0036.56 0.39 0.02 0.01 0.01 0.01 0.0136.58 0.73 0.02 0.01 0.02 0.01 0.0236.60 1.17 0.02 0.02 0.04 0.02 0.0436.62 1.71 0.02 0.03 0.07 0.03 0.0736.64 2.36 0.02 0.04 0.11 0.04 0.1136.66 3.14 0.02 0.05 0.16 0.05 0.1636.68 0.00 0.02 0.03 0.19 0.02 0.1836.68 4.04 0.00 0.00 0.19 0.00 0.1836.70 0.27 0.02 0.04 0.24 0.04 0.2236.70 5.06 0.00 0.00 0.24 0.00 0.2236.72 1.01 0.02 0.06 0.30 0.06 0.2736.72 6.20 0.00 0.00 0.30 0.00 0.2736.74 1.94 0.02 0.08 0.38 0.08 0.3536.74 7.47 0.00 0.00 0.38 0.00 0.3536.76 11.87 0.02 0.19 0.57 0.19 0.5436.78 14.55 0.02 0.26 0.84 0.26 0.8136.80 17.45 0.02 0.32 1.16 0.32 1.1336.82 20.57 0.02 0.38 1.54 0.38 1.5136.84 23.90 0.02 0.44 1.98 0.44 1.9536.86 27.50 0.02 0.51 2.49 0.51 2.4636.88 32.12 0.02 0.60 3.09 0.60 3.0636.90 36.34 0.02 0.68 3.78 0.68 3.7436.92 40.23 0.02 0.77 4.54 0.77 4.5136.94 44.06 0.02 0.84 5.38 0.84 5.3536.96 47.85 0.02 0.92 6.30 0.92 6.2736.98 51.61 0.02 0.99 7.30 0.99 7.2637.00 56.03 0.02 1.08 8.37 1.08 8.34
37.02 72.18 0.02 1.28 9.66 1.28 9.62
37.04 103.69 0.02 1.76 11.42 1.75 11.3737.06 133.62 0.02 2.37 13.79 2.37 13.7337.08 155.23 0.02 2.89 16.68 2.89 16.6237.10 198.15 0.02 3.53 20.21 3.53 20.1537.36 4.20 0.26 26.30 46.51 20.04 40.1837.36 5.40 0.00 0.00 46.51 0.00 40.1837.38 0.40 0.02 0.06 46.57 0.05 40.2337.38 3.41 0.00 0.00 46.57 0.00 40.23 Flood Report #25
Project: El Camino Real Dewatering ProjectBasin Description: Stockbridge AveContour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (ft) Volume Volume Volume Volume (sq. ft) Avg. End Avg. End Conic Conic (cu. ft) (cu. ft) (cu. ft) (cu. ft)
41.75 277.16 N/A N/A 0.00 N/A 0.0041.80 236.34 0.05 12.84 12.84 12.82 12.8241.85 198.51 0.05 10.87 23.71 10.86 23.6841.90 163.96 0.05 9.06 32.77 9.05 32.7341.95 132.75 0.05 7.42 40.19 7.40 40.1342.00 104.88 0.05 5.94 46.13 5.93 46.0642.05 80.35 0.05 4.63 50.76 4.62 50.6842.10 59.16 0.05 3.49 54.25 3.47 54.1542.15 41.31 0.05 2.51 56.76 2.50 56.6542.20 26.79 0.05 1.70 58.46 1.69 58.3442.25 15.61 0.05 1.06 59.52 1.05 59.3942.30 5.14 0.05 0.52 60.04 0.50 59.88 Flood Report #8
Project: El Camino Real Dewatering ProjectBasin Description: Stockbridge Ave.Contour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (ft) Volume Volume Volume Volume (sq. ft) Avg. End Avg. End Conic Conic (cu. ft) (cu. ft) (cu. ft) (cu. ft)
41.80 0.33 N/A N/A 0.00 N/A 0.0041.85 0.78 0.05 0.03 0.03 0.03 0.0341.90 1.35 0.05 0.05 0.08 0.05 0.0841.95 2.02 0.05 0.08 0.17 0.08 0.1642.00 2.62 0.05 0.12 0.28 0.12 0.2842.05 3.44 0.05 0.15 0.43 0.15 0.4342.10 4.51 0.05 0.20 0.63 0.20 0.6342.15 5.81 0.05 0.26 0.89 0.26 0.8942.20 7.98 0.05 0.34 1.23 0.34 1.2342.25 10.68 0.05 0.47 1.70 0.46 1.6942.30 14.68 0.05 0.63 2.33 0.63 2.3242.35 20.30 0.05 0.87 3.21 0.87 3.2042.40 27.10 0.05 1.18 4.39 1.18 4.3842.45 34.27 0.05 1.53 5.93 1.53 5.9142.50 41.95 0.05 1.91 7.83 1.90 7.8142.55 49.80 0.05 2.29 10.13 2.29 10.1042.58 54.37 0.03 1.56 11.69 1.56 11.6642.60 57.36 0.02 1.12 12.81 1.12 12.7842.60 7.65 0.00 0.00 12.81 0.00 12.7842.65 51.24 0.05 1.47 14.28 1.31 14.0942.65 64.72 0.00 0.00 14.28 0.00 14.0942.65 929.14 0.00 0.00 14.28 0.00 14.0942.70 199.16 0.05 28.21 42.49 25.97 40.0742.75 294.31 0.05 12.34 54.82 12.26 52.3342.80 381.79 0.05 16.90 71.73 16.86 69.1842.85 476.17 0.05 21.45 93.18 21.41 90.5942.90 577.61 0.05 26.34 119.52 26.30 116.8942.95 686.20 0.05 31.60 151.12 31.56 148.4543.00 802.42 0.05 37.22 188.33 37.18 185.62
43.05 930.01 0.05 43.31 231.64 43.27 228.89
Flood Report #99
Project: El Camino Real Dewatering ProjectBasin Description: Stockbridge Ave. Contour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (ft) Volume Volume Volume Volume (sq. ft) Avg. End Avg. End Conic Conic (cu. ft) (cu. ft) (cu. ft) (cu. ft)
42.15 4.26 N/A N/A 0.00 N/A 0.0042.15 4.59 0.00 0.00 0.00 0.00 0.0042.15 1.30 0.00 0.00 0.00 0.00 0.0042.20 27.89 0.05 0.73 0.73 0.59 0.5942.20 6.10 0.00 0.00 0.73 0.00 0.5942.25 62.82 0.05 1.72 2.45 1.47 2.0642.30 17.71 0.05 2.01 4.47 1.90 3.9642.30 133.57 0.00 0.00 4.47 0.00 3.9642.35 8.91 0.05 3.56 8.03 2.95 6.9142.35 198.32 0.00 0.00 8.03 0.00 6.9142.40 1.54 0.05 5.00 13.02 3.62 10.5342.40 271.30 0.00 0.00 13.02 0.00 10.5342.45 339.91 0.05 15.28 28.30 15.25 25.7842.50 390.33 0.05 18.26 46.56 18.24 44.0242.55 446.72 0.05 20.93 67.49 20.91 64.9342.55 1.26 0.00 0.00 67.49 0.00 64.9342.58 492.79 0.03 7.41 74.90 5.19 70.1242.58 5.00 0.00 0.00 74.90 0.00 70.1242.60 535.00 0.02 5.40 80.30 3.94 74.0742.60 8.39 0.00 0.00 80.30 0.00 74.0742.65 582.37 0.05 14.77 95.07 11.01 85.0842.67 82.43 0.02 6.65 101.71 5.89 90.9742.75 15.98 0.08 3.94 105.65 3.59 94.5642.80 11.15 0.05 0.68 106.33 0.67 95.2442.85 7.19 0.05 0.46 106.79 0.45 95.69 Flood Report #89
Project: El Camino Real Dewatering ProjectBasin Description: Almendral Ave.Contour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (ft) Volume Volume Volume Volume (sq. ft) Avg. End Avg. End Conic Conic (cu. ft) (cu. ft) (cu. ft) (cu. ft)
47.35 1.90 N/A N/A 0.00 N/A 0.0047.40 8.02 0.05 0.25 0.25 0.23 0.2347.45 18.09 0.05 0.65 0.90 0.64 0.8747.50 38.62 0.05 1.42 2.32 1.39 2.2547.55 73.53 0.05 2.80 5.12 2.76 5.0147.60 125.98 0.05 4.99 10.11 4.93 9.9447.65 203.95 0.05 8.25 18.36 8.17 18.1147.70 304.75 0.05 12.72 31.08 12.63 30.7447.75 414.54 0.05 17.98 49.06 17.91 48.6547.80 537.47 0.05 23.80 72.86 23.73 72.3947.85 712.77 0.05 31.26 104.11 31.15 103.5447.85 679.90 0.00 0.00 104.11 0.00 103.54 Flood Report #101
Project: El Camino Real Dewatering ProjectBasin Description: ECRContour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (ft) Volume Volume Volume Volume (sq. ft) Avg. End Avg. End Conic Conic (cu. ft) (cu. ft) (cu. ft) (cu. ft)
46.96 0.06 N/A N/A 0.00 N/A 0.0046.98 0.38 0.02 0.00 0.00 0.00 0.0047.00 0.97 0.02 0.01 0.02 0.01 0.0247.02 1.84 0.02 0.03 0.05 0.03 0.0447.04 2.99 0.02 0.05 0.09 0.05 0.0947.06 4.39 0.02 0.07 0.17 0.07 0.1747.08 5.83 0.02 0.10 0.27 0.10 0.2747.10 7.27 0.02 0.13 0.40 0.13 0.4047.12 8.71 0.02 0.16 0.56 0.16 0.5647.14 10.14 0.02 0.19 0.75 0.19 0.7547.16 11.56 0.02 0.22 0.97 0.22 0.9647.18 13.07 0.02 0.25 1.21 0.25 1.2147.20 15.27 0.02 0.28 1.50 0.28 1.4947.22 17.52 0.02 0.33 1.82 0.33 1.8247.24 19.73 0.02 0.37 2.20 0.37 2.1947.26 21.92 0.02 0.42 2.61 0.42 2.6147.28 24.08 0.02 0.46 3.07 0.46 3.0747.30 26.22 0.02 0.50 3.58 0.50 3.5747.32 28.32 0.02 0.55 4.12 0.55 4.1247.34 30.41 0.02 0.59 4.71 0.59 4.7047.36 32.46 0.02 0.63 5.34 0.63 5.3347.38 34.51 0.02 0.67 6.01 0.67 6.0047.40 36.57 0.02 0.71 6.72 0.71 6.7147.42 39.22 0.02 0.76 7.48 0.76 7.4747.44 43.38 0.02 0.83 8.30 0.83 8.3047.46 47.68 0.02 0.91 9.21 0.91 9.2147.46 0.17 0.00 0.00 9.21 0.00 9.2147.48 51.16 0.02 0.51 9.73 0.36 9.5747.48 1.11 0.00 0.00 9.73 0.00 9.57
47.50 55.01 0.02 0.56 10.29 0.43 9.99
47.50 2.86 0.00 0.00 10.29 0.00 9.9947.52 59.28 0.02 0.62 10.91 0.50 10.5047.52 5.42 0.00 0.00 10.91 0.00 10.5047.54 73.14 0.02 0.79 11.69 0.66 11.1547.56 82.98 0.02 1.56 13.25 1.56 12.7147.58 93.73 0.02 1.77 15.02 1.77 14.4847.60 105.83 0.02 2.00 17.02 1.99 16.4747.62 119.35 0.02 2.25 19.27 2.25 18.7247.64 133.53 0.02 2.53 21.80 2.53 21.2547.66 148.12 0.02 2.82 24.61 2.82 24.0747.68 163.38 0.02 3.11 27.73 3.11 27.1847.68 0.03 0.00 0.00 27.73 0.00 27.1847.70 179.61 0.02 1.80 29.53 1.21 28.3947.70 4.19 0.00 0.00 29.53 0.00 28.3947.72 210.64 0.02 2.15 31.67 1.63 30.0247.74 240.05 0.02 4.51 36.18 4.50 34.5347.76 274.50 0.02 5.15 41.33 5.14 39.6747.78 313.28 0.02 5.88 47.20 5.87 45.5447.78 2.01 0.00 0.00 47.20 0.00 45.5447.80 356.39 0.02 3.58 50.79 2.57 48.1147.80 10.74 0.00 0.00 50.79 0.00 48.1147.82 424.14 0.02 4.35 55.14 3.35 51.46 Flood Report #101 (2)
Project: El Camino Real Dewatering ProjectBasin Description: ECRContour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (ft) Volume Volume Volume Volume (sq. ft) Avg. End Avg. End Conic Conic (cu. ft) (cu. ft) (cu. ft) (cu. ft)
47.72 0.80 N/A N/A 0.00 N/A 0.0047.74 3.57 0.02 0.04 0.04 0.04 0.0447.76 8.32 0.02 0.12 0.16 0.12 0.1647.78 15.00 0.02 0.23 0.40 0.23 0.3947.78 1.08 0.00 0.00 0.40 0.00 0.3947.80 22.50 0.02 0.24 0.63 0.19 0.5847.80 11.01 0.00 0.00 0.63 0.00 0.5847.82 30.27 0.02 0.41 1.04 0.40 0.9747.82 30.36 0.00 0.00 1.04 0.00 0.9747.84 96.97 0.02 1.27 2.32 1.21 2.18 Flood Report #110 (1)
Project: El Camino Real Dewatering ProjectBasin Description: Isabella AveContour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (ft) Volume Volume Volume Volume (sq. ft) Avg. End Avg. End Conic Conic (cu. ft) (cu. ft) (cu. ft) (cu. ft)
56.15 11.02 N/A N/A 0.00 N/A 0.0056.20 28.46 0.05 0.99 0.99 0.95 0.9556.25 49.36 0.05 1.95 2.93 1.92 2.8856.25 0.93 0.00 0.00 2.93 0.00 2.8856.30 39.99 0.05 1.02 3.96 0.78 3.6656.30 81.28 0.00 0.00 3.96 0.00 3.6656.35 265.37 0.05 8.67 12.62 8.23 11.88 Flood Report #110 (2)
Project: El Camino Real Dewatering ProjectBasin Description: Isabella AveContour Contour Depth Incremental Cumulative Incremental Cumulative Elevation Area (ft) Volume Volume Volume Volume (sq. ft) Avg. End Avg. End Conic Conic (cu. ft) (cu. ft) (cu. ft) (cu. ft)
56.15 0.59 N/A N/A 0.00 N/A 0.0056.20 25.93 0.05 0.66 0.66 0.51 0.5156.25 79.51 0.05 2.64 3.30 2.51 3.0256.35 315.87 0.10 19.77 23.07 18.46 21.4856.35 291.34 0.00 0.00 23.07 0.00 21.4856.35 0.00 0.00 0.00 23.07 0.00 21.4856.35 0.00 0.00 0.00 23.07 0.00 21.4856.35 0.00 0.00 0.00 23.07 0.00 21.48 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D JOB NO. SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com TOWN OF ATHERTON ······ ABBREVIATIONS: LEGEND:
12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D JOB NO. SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com GENERAL NOTES: GENERAL NOTES (CONTINUED): EROSION AND SEDIMENT CONTROL NOTES:
12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.0 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.1 © 2025 Microsoft Corporation © 2025 Maxar ©CNES (2025) Distribution Airbus DS © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2025 Microsoft Corporation © 2025 Maxar ©CNES (2025) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.2 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.3 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.4 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 4.0 ° Æ °
12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 4.1
4.2 12/20/2024
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EB
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CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS
150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com
12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D JOB NO. SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com TOWN OF ATHERTON ······ ABBREVIATIONS: LEGEND:
12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D JOB NO. SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com GENERAL NOTES: GENERAL NOTES (CONTINUED): EROSION AND SEDIMENT CONTROL NOTES:
© 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.0 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.1 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.2 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.3 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.4 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.5 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.6 © 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.7 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.8 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 3.9 ° Æ 12/20/2024 PROJ. ENGR: DRAWN: CHECKED: SCALE: DESIGNED: DATE: DESCRIPTION OF REVISIONS EB DATE ITEBIT APP'D 373001 JOB NO. OF - SHEETS SHEET CONCEPTUAL DESIGN CIVIL ENGINEERS • SURVEYORS • CONSTRUCTION MANAGERS 150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com 4.0
4.1 12/20/2024
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150 Executive Park Blvd • Suite 4200 • San Francisco, CA 94134 (415) 534-7070 • www.freyerlaureta.com
Company
Contact
Phone No.
PROPOSAL
NP 3069 MT 3~ ADAPTIVE 434
Created On: 3/19/25
Project:
NP 3069 MT 3~ Adaptive 434
Created By:
Garrett Young
Created On:
3/19/25
Last Update:
-
NP 3069 MT 3~ Adaptive 434 | Configuration Summary
Flygt's self-cleaning non-clog N-pumps feature innovative designs and functions that deliver high sustained efficiency and the most reliable operation. This makes them the most reliable choice available for a broad range of wastewater applications for tough applications such as unscreened sewage, wastewater and sludge up to an 8 percent solids concentration. Impeller material available in Hardened cast Iron, Hard Iron and Stainless Steel to fit any wastewater application.
Nominal (mean) data shown. Under- and over-performance from this data should be expected due to standard manufacturing tolerances. Please consult your local Flygt representative for performance guarantees.
Installation
Installation Type
P - Semi-Permanent, Wet
Motor
Rated Voltage
460 V
Coupling
Y
Motor Efficiency Class
Standard
Rated Power
2.4 Hp
Materials
Impeller Material
Hard-Iron
Volute Material
Grey Cast Iron
Stator Cover Material
Grey Cast Iron
Performance
Explosion Proof
true
Approval
FM
Max. Pumped Media Temp.
104 °F
Impeller Diameter
152 mm
Project:
NP 3069 MT 3~ Adaptive 434
Created By:
Garrett Young
Created On:
3/19/25
Last Update:
-
NP 3069 MT 3~ Adaptive 434 | Product Details
N 3069
Wastewater N-Technology Pump With Adaptive N® Impeller
Flygt N-pumps take on the toughest applications and get the job done. Every component is designed and manufactured to deliver sustained high efficiency. Thanks to patented N-technology with its innovative self-cleaning impeller, Flygt N-pumps deliver the highest total efficiency. They lower your energy bill and reduce unplanned maintenance costs. That adds up to total peace of mind – and big savings over the long term. Most solid objects entering the pump will pass through the impeller between the impeller vanes. If an object gets caught on the leading edge of one of the vanes, it will slide along the backswept shape towards the perimeter of the inlet.
Flexible and Modular Design
o This self-cleaning pump features innovative functions that make it the best choice for a broad range of applications. The modular hydraulic design enables you to tailor the hydraulics to meet the requirements of virtually any application. Replaceable wear ring in two materials, gray iron or Hard-Iron, for different operation conditions o Hardened gray iron impeller for typical wastewater applications o Hard-Iron impeller for abrasive and corrosive applications o Stainless steel impeller for special applications that require duplex stainless steel o Short shaft overhang reduces shaft deflection and increases seal and bearing life o Motor designed for submersible use. Heat is concentrated to the stator core for improved cooling properties o The double mechanical seal system consists of two sets of mechanical shaft seals that work independently to provide double security. o Griploc mechanical face seal system secures locking to the shaft, no rubber friction, no grub screws and no shaft damage o Motor cable SUBCAB ® specially developed for submersible use.
Product Features
o Sustained high efficiency
o Hardened cast iron, optional Duplex stainless steel and Hard-Iron impellers o State-of-the-art wastewater pump with enhanced Adaptive N® hydraulic o Sustained high efficiency with energy savings up to 25% o Flexible and modular design
o Robust and reliable
Construction Materials
Impeller Material
Hard-Iron
Volute Material
Grey Cast Iron
Stator Cover Material
Grey Cast Iron
Motor
Rated Power
2.4 Hp
Motor Denomination
13-08-4BB
Motor Efficiency Class
Standard
Version Code
070
Frequency
60 Hz
Max P2 (1x)
2.36 Hp
Number Of Poles
4 Number Of Phases
3 Rated Motor Speed
1,705 RPM
Rated Voltage
460 V
Rated Current
4 A
Start Current
17 A
Starting Current, Direct Starting
17 A
Starting Current, Star Delta
5.67 A
Start Current Ratio
4.24 Insulation Class
F
Approval
FM
Total moment of inertia
0.2815 ft²lbf
Type of duty
S1
Stator Variant
1 Motor Module
151
Motor Issue
12 Locked Rotor Code
G
Max starts per hour
15 Power Factor 100%
0.78 Power Factor 75%
0.68 Power Factor 50%
0.54 Efficiency 100%
71.3 %
Efficiency 75%
71.9 %
Efficiency 50%
68.6 %
Project:
NP 3069 MT 3~ Adaptive 434
Created By:
Garrett Young
Created On:
3/19/25
Last Update:
-
NP 3069 MT 3~ Adaptive 434 |Hydraulic Data & Performance Curve Nominal (mean) data shown. Under- and over-performance from this data should be expected due to standard manufacturing tolerances. Please consult your local Flygt representative for performance guarantees.
Project:
NP 3069 MT 3~ Adaptive 434
Created By:
Garrett Young
Created On:
3/19/25
Last Update:
-
Selection Fluid
Series
N 3000
Name
NP 3069 MT 3~ Adaptive 434
Frequency
60 Hz
Total Flow
300.00 USgpm
Total Head
10.00 ft
Pump Flow
300.00 USgpm
Pump Head
10.00 ft
System Type
Single Pump
Operating Pumps
1 Standby Pumps
No Standby Pump
Curve Code
434
Impeller Diameter
152 mm
Inlet Diameter
113 mm
Outlet Diameter
3 in
Number Of Vanes
2 Fluid Type
Water
Fluid Temperature
39.2 °F
Specific Gravity
1 Density
62.428 lb/ft³
Dynamic Viscosity
1.567212 cP
Fluid Vapor Pressure
0.118 psi
Design Point Design Curve
Flow
356.58 USgpm
Head
12.48 ft
Overall Efficiency (ηo)
35.04 %
Pump Efficiency (ηp)
48.96 %
Input Power (P1)
3.21 Hp
Shaft power (P2)
2.3 Hp
NPSHR
16.21 ft
Static Head
4.00 ft
Flow To BEP Ratio
111.9 %
Rated Speed
60 Hz
Max Flow
577.05 USgpm
H@QMin
28.24 ft
H@QMax
2.79 ft
BEP
49.6 %
BEP Flow
318.67 USgpm
BEP Head
13.96 ft
Max P2
2.36 Hp
Specific Energy
0.000112 kWh/USgal
Project:
NP 3069 MT 3~ Adaptive 434
Created By:
Garrett Young
Created On:
3/19/25
Last Update:
-
NP 3069 MT 3~ Adaptive 434 | Duty Analysis
Nominal (mean) data shown. Under- and over-performance from this data should be expected due to standard manufacturing tolerances. Please consult your local Flygt representative for performance guarantees.
Name Q (1x)
[USgpm]
H (1x)
[ft]
P2 (1x)
[Hp]
Q
[USgpm]
H
[ft]
P2
[Hp]
ηp
[%]
SE
[kWh/USgal]
NPSHr
[ft]
DP @ 1x 356.58 12.48 2.3 356.58 12.48 2.3 48.96 0 16.21 Project:
NP 3069 MT 3~ Adaptive 434
Created By:
Garrett Young
Created On:
3/19/25
Last Update:
-
NP 3069 MT 3~ Adaptive 434 | Dimensional Data & Drawing Company SHAPE Inc
Contact Garrett Young
Phone No. 9259976632
Email [email protected]
NP 3102 LT 3~ ADAPTIVE 423
Created On: 5/1/25
Project:
NP 3102 LT 3~ Adaptive 423
Created By:
Travis Harper
Created On:
5/1/25
Last Update:
-
NP 3102 LT 3~ Adaptive 423 | Configuration Summary
Flygt's self-cleaning non-clog N-pumps feature innovative designs and functions that deliver high sustained efficiency and the most reliable operation. This makes them the most reliable choice available for a broad range of wastewater applications for tough applications such as unscreened sewage, wastewater and sludge up to an 8 percent solids concentration. Impeller material available in Hardened cast Iron, Hard Iron and Stainless Steel to fit any wastewater application.
Nominal (mean) data shown. Under- and over-performance from this data should be expected due to standard manufacturing tolerances. Please consult your local Flygt representative for performance guarantees.
Installation
Installation Type
P - Semi-Permanent, Wet
Motor
Rated Voltage
460 V
Coupling
Y
Motor Efficiency Class
Standard
Rated Power
5 Hp
Materials
Impeller Material
Hard-Iron
Volute Material
Grey Cast Iron
Stator Cover Material
Grey Cast Iron
Performance
Explosion Proof
No
Max. Pumped Media Temp.
104 °F
Impeller Diameter
158 mm
Project:
NP 3102 LT 3~ Adaptive 423
Created By:
Travis Harper
Created On:
5/1/25
Last Update:
-
NP 3102 LT 3~ Adaptive 423 | Product Details
Description
N 3102
Wastewater N-Technology Pump With Adaptive N® Impeller
Flygt N-pumps take on the toughest applications and get the job done. Every component is designed and manufactured to deliver sustained high efficiency. Thanks to patented N-technology with its innovative self-cleaning impeller, Flygt N-pumps deliver the highest total efficiency. They lower your energy bill and reduce unplanned maintenance costs. That adds up to total peace of mind – and big savings over the long term. Most solid objects entering the pump will pass through the impeller between the impeller vanes. If an object gets caught on the leading edge of one of the vanes, it will slide along the backswept shape towards the perimeter of the inlet. Due to the mechanical self-cleaning design, a sludge concentration up to 8% can easily be pumped.
Flexible and Modular Design
o This self-cleaning pump features innovative functions that make it the best choice for a broad range of applications. The modular hydraulic design enables you to tailor the hydraulics to meet the requirements of virtually any application.
o Replaceable wear ring in two materials, gray iron or Hard-Iron, for different operation conditions o Hardened gray iron impeller for typical wastewater applications o Hard-Iron impeller for abrasive and corrosive applications o Stainless steel impeller for special applications that require duplex stainless steel o Short shaft overhang reduces shaft deflection and increases seal and bearing life o Motor designed for submersible use. Heat is concentrated to the stator core for improved cooling properties o The double mechanical seal system consists of two sets of mechanical shaft seals that work independently to provide double security. Available in Tungsten carbide (WCCR) or Silicone carbide (SiC) depending on pumped media.
o Griploc mechanical face seal system secures locking to the shaft, no rubber friction, no grub screws and no shaft damage o Motor cable SUBCAB ® specially developed for submersible use.
Product Features
o Sustained high efficiency
o Hardened cast iron, optional Duplex stainless steel and Hard-Iron impellers o State-of-the-art wastewater pump with enhanced Adaptive N® hydraulic o Sustained high efficiency with energy savings up to 25% o Flexible and modular design
o Robust and reliable
Construction Materials
Impeller Material
Hard-Iron
Volute Material
Grey Cast Iron
Stator Cover Material
Grey Cast Iron
Motor
Rated Power
5 Hp
Motor Denomination
18-11-4AL
Motor Efficiency Class
Standard
Version Code
060
Frequency
60 Hz
Max P2 (1x)
4.41 Hp
Number Of Poles
4 Number Of Phases
3 Rated Motor Speed
1,760 RPM
Rated Voltage
460 V
Rated Current
7 A
Start Current
40 A
Starting Current, Direct Starting
40 A
Starting Current, Star Delta
13.33 A
Start Current Ratio
6.09 Insulation Class
H
Approval
Standard
Total moment of inertia
0.6432 ft²lbf
Type of duty
S1
Stator Variant
62 Motor Module
135
Motor Issue
12 Locked Rotor Code
H
Max starts per hour
30 Power Factor 100%
0.82 Power Factor 75%
0.77 Power Factor 50%
0.65 Efficiency 100%
86.8 %
Efficiency 75%
87.5 %
Efficiency 50%
86.6 %
Project:
NP 3102 LT 3~ Adaptive 423
Created By:
Travis Harper
Created On:
5/1/25
Last Update:
-
NP 3102 LT 3~ Adaptive 423 |Hydraulic Data & Performance Curve Nominal (mean) data shown. Under- and over-performance from this data should be expected due to standard manufacturing tolerances. Please consult your local Flygt representative for performance guarantees.
Project:
NP 3102 LT 3~ Adaptive 423
Created By:
Travis Harper
Created On:
5/1/25
Last Update:
-
Selection Fluid
Series
N 3000
Name
NP 3102 LT 3~ Adaptive 423
Frequency
60 Hz
Total Flow
650.00 USgpm
Total Head
25.00 ft
Pump Flow
325.00 USgpm
Pump Head
25.00 ft
System Type
Parallel Pumps
Operating Pumps
2 Standby Pumps
No Standby Pump
Curve Code
423
Impeller Diameter
158 mm
Inlet Diameter
150 mm
Outlet Diameter
6 in
Number Of Vanes
2 Fluid Type
Water
Fluid Temperature
39.2 °F
Specific Gravity
1 Density
62.428 lb/ft³
Dynamic Viscosity
1.567212 cP
Fluid Vapor Pressure
0.118 psi
Design Point - Single Pump Design Point - System
Flow (1x)
335.8 USgpm
Head (1x)
25.47 ft
Overall Efficiency (1x)
45.22 %
Pump Efficiency (1x)
51.89 %
Input Power (P1) (1x)
4.79 Hp
Shaft power (P2) (1x)
4.17 Hp
NPSHr (1x)
13.43 ft
Static Head
18.00 ft
Flow To BEP Ratio (1x)
55.1 %
Flow
671.6 USgpm
Head
25.47 ft
Overall Efficiency (ηo)
45.22 %
Pump Efficiency (ηp)
51.89 %
Input Power (P1)
9.57 Hp
Shaft power (P2)
8.34 Hp
NPSHR
13.43 ft
Static Head
18.00 ft
Flow To BEP Ratio
55.1 %
Design Curve - Single Pump Design Curve - System
Rated Speed
60 Hz
Max Flow (1x)
1,092.61 USgpm
H@QMin (1x)
35.11 ft
H@QMax (1x)
3.22 ft
BEP (1x)
65.6 %
BEP Flow (1x)
609.8 USgpm
BEP Head (1x)
18.6 ft
Max P2 (1x)
4.41 Hp
Rated Speed
60 Hz
Max Flow
2,185.23 USgpm
H@QMin
35.11 ft
H@QMax
3.22 ft
BEP
65.6 %
BEP Flow
1,219.61 USgpm
BEP Head
18.6 ft
Max P2
8.81 Hp
Specific Energy
0.000177 kWh/USgal
Project:
NP 3102 LT 3~ Adaptive 423
Created By:
Travis Harper
Created On:
5/1/25
Last Update:
-
NP 3102 LT 3~ Adaptive 423 | Duty Analysis
Nominal (mean) data shown. Under- and over-performance from this data should be expected due to standard manufacturing tolerances. Please consult your local Flygt representative for performance guarantees.
Name Q (1x)
[USgpm]
H (1x)
[ft]
P2 (1x)
[Hp]
Q
[USgpm]
H
[ft]
P2
[Hp]
ηp
[%]
SE
[kWh/USgal]
NPSHr
[ft]
DP @ 1x 486.38 21.92 4.29 486.38 21.92 4.29 62.8 0 13.03 DP @ 2x 335.8 25.47 4.17 671.6 25.47 8.34 51.89 0 13.43 Project:
NP 3102 LT 3~ Adaptive 423
Created By:
Travis Harper
Created On:
5/1/25
Last Update:
-
NP 3102 LT 3~ Adaptive 423 | Dimensional Data & Drawing Company Shape
Contact Travis Harper
Phone No. 9168925147
Email [email protected]
ENGINEER’S ESTIMATE
CONSTRUCTION COST
ALIGNMENT 1 – SELBY LN. LS
Item No Item Unit Quantity Unit Price Total Cost
Mobilization/Swpp/Traffic Control - - - $ 34,500
1 Mobilization/Demobilization LS 1 $ 7,000 $ 7,000
2 Traffic Control LS 1 $ 5,000 $ 5,000
3 Construction Staking & Survey LS 1 $ 17,500 $ 17,500
4 Stormwater Pollution Prevention LS 1 $ 5,000 $ 5,000
Drain Inlets/Manholes - - - $ 691,600
5 Sheeting, Shoring, & Bracing LS 1 $ 22,500 $ 22,500
6 Dewatering Operations LS 1 $ 8,500 $ 8,500
7 12" HDPE Storm Drain by Open Trench LF 1,260 $ 320 $ 403,200 8 6" HDPE Forcemain by Open Trench LF 420 $ 200 $ 84,000 9 Curb Catch Basins EA 4 $ 8,300 $ 33,200
10 48" Diameter Storm Drain Manhole EA 4 $ 35,000 $ 140,000 11 Pop-up Emitter EA 1 $ 200 $ 200
Supplementary Grading - - - $ 104,050
12 Regrading SF 1,370 $ 65 $ 89,050
13 Valley Gutter LF 100 $ 150 $ 15,000
14 Dewatering Station at Selby Lane (Pumps, Wet
Well, Control Center, Valve Pit, SCADA, new
PG&E service)
LS 1 $ 125,000 $ 125,000
Subtotal $955,200
Contigency (10%) $100,000
Total $1,055,200
ENGINEER’S ESTIMATE
CONSTRUCTION COST
ALIGNMENT 2 – ISABELLA AVE. LS
Item No Item Unit Quantity Unit Price Total Cost
Mobilization/SWPP/Traffic Control - - - $ 65,500
1 Mobilization/Demobilization LS 1 $ 13,000 $ 13,000
2 Traffic Control LS 1 $ 10,000 $ 10,000
3 Construction Staking & Survey LS 1 $ 32,500 $ 32,500
4 Stormwater Pollution Prevention LS 1 $ 10,000 $ 10,000 Drain Inlets/Manholes - - - $ 576,800
5 Sheeting, Shoring, & Bracing LS 1 $ 42,500 $ 42,500
6 Dewatering Operations LS 1 $ 16,500 $ 16,500
7 Storm Drain Inlet EA 6 $ 6,000 $ 36,000
8 Curb Catch Basins EA 6 $ 8,300 $ 49,800
9 48" dia 24”Diameter Storm Drain Manhole EA 11 $ 35,000 $ 420,000 10 48” Deep Storm Drain Manhole EA 1 $ 12,000 $ 12,000
11 Horizontal Directional Drilling LF 3322 $ 625 $ 2,076,250 12 New Outfall to Atherton Channel LS 1 $ 50,000 $ 50,000 Supplementary Grading - - - $ 153,450
13 Regrading SF 2,130 $ 65 $ 138,450
14 Valley Gutter LF 100 $ 50 $ 15,000
15 Dewatering Station At Isabella Ave (Pumps, Wet Well, Control Center, Valve Pit, SCADA, New PG&E Service)
LS 1 $ 400,000 $ 400,000
Subtotal $ 3,322,000
Contigency (10%) $ 340,000
Total $ 3,662,000