“CWE demonstrated exceptional project management and civil engineering design expertise. They effectively completed PS&Es for this complex system on a compressed schedule and met all project and grant funding timelines and requirements.
The PS&Es delivered were of outstanding quality and minimized the need for construction change orders. CWE’s Project Manager was very knowledgeable and had a firm handle on all aspects of the project. I strongly recommend using CWE for any civil engineering projects you may be considering.”
City of Los Angeles Garvanza Park Rainwater Capture and Use
Wing Tam, PE Assistant Division Manager
LA Sanitation – City of Los Angeles
Project Scope
Garvanza Park was retrofitted to enhance the water quality of runoff from an 85-acre watershed by retaining over one million gallons of urban runoff during each storm event. CWE assisted LA Sanitation, the City of Los Angeles, and North East Trees by conducting a study and design analysis. This determined the feasibility of routing urban and stormwater runoff from an existing 48-inch reinforced concrete storm drain pipe into a Best Management Practice (BMP) system.
The Garvanza Park system consisted of:
- A Hydrodynamic Separator and Settling Basin
- One Water-Tight Subsurface Detention Gallery
- One Subsurface Infiltration Gallery for Onsite Landscape Irrigation Use and Infiltration
CWE was first tasked with evaluating the existing conditions. This involved a full analyses of the site’s drainage capabilities, pollutant loads, current utilities and ground surveys. Feasibility and forecasting studies were conducted to determine the best way for the city to move forward.
Using this analysis and feasibility research, CWE began planning site enhancements. Starting with conceptual sketches, CWE started the process of designing stormwater treatment BMP infrastructures. Modifications and improvements were designed for existing infrastructure. Upgraded pump station designs were generated. Grading and drainage plans were generated to improve overall site performance while drastically reducing site erosion.
Additionally, the project provided for inline gross pollutant detection system that activated valves to shut the system down in cases of emergency. CWE also provided construction administration services, including supervision and inspections during the project’s construction phase. Water quality sampling was provided to evaluate project effectiveness.
Details
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Awards
This project received the prestigious:
California Stormwater Quality Association (CASQA) Outstanding Stormwater Best Management Practice (BMP) Implementation Project Award.
Existing and Best Practice Analysis
- Assessing Existing Storm Drain
- Drainage Analysis
- Delineating & Characterizing the Tributary Watershed
- Hydrologic/Hydraulic Calculations/Modeling
- Feasibility Report: Hydrology Study Findings and Anticipated Pollutant Loads
- Topographic Ground Survey & Utility Search
- Potholing
- Supervising a Geotechnical Analysis Including Infiltration Testing & Shoring Analysis
Enhancements
- Developing Conceptual Sketches
- Designing Stormwater Treatment BMP Infrastructure
- Storm Drain Modification
- Pump Station Design
- Supervisory Control and Data Acquisition (SCADA) System
- Design Plans (Including Grading, Drainage, and Erosion Control)
- Stormwater Pollution Prevention Plan (SWPPP)
