Detention Basins

The District 12 State Route 73 Pilot Program was a multi-year field study conducted in Orange County. The primary objective was to assess the effectiveness of twenty-four pilot Best Management Practices (BMPs) for treating stormwater runoff from freeways. Included in the program were twenty detention basins. Different modes of operation (e.g., bypass, overflow, and batch) and different design volume fractions (e.g., 0.25, 0.50, 0.75, and 1.00) were investigated. Additionally, alternative inlets and outlets were investigated. Influent and effluent water quality samples were collected and compared, and operation and maintenance activities were recorded to develop maintenance protocols for the modified detention basins.

OWP Tasks

• Assisted in Study Planning
• Reviewed Designs of Detention Basins
• Provided Review of Installation/Construction Activities
• Provided Monitoring Assistance

Report/Study Link:
Caltrans District 12 State Route 73 Pilot Program – Detention Basins
OWP Contacts: David Alderete

The Caltrans Tahoe Basin Stormwater Pilot Program consists of both small-scale and full-scale pilot studies. Small-scale settling columns were constructed and operated intermittently to treat discrete batches of stormwater collected from various runoff events. The primary objective of this study was to determine the effectiveness of stormwater detention in reducing turbidity and nutrients from Tahoe stormwater runoff.

OWP Tasks

• Assisted in Study Planning
• Reviewed Experimental Designs and Methods
• Provided Technical Assistance
• Assessed Study Results
• Reviewed Study Reports and Recommendations

Report/Study Link:
Caltrans Tahoe Basin Small-Scale Pilot Studies – Detention/Settling
OWP Contacts: Dipen Patel | John Johnston

As part of the Caltrans Tahoe Basin Stormwater Pilot Program, four full-scale detention basins were designed and constructed on SR 267. These basins were designed as conventional detention basins or hold and release basins that utilize outlet valves to control the hold time of water. The objectives of this study were to determine the effectiveness of conventional and hold and release detention basins in removing turbidity and nutrients, hydraulic performance of the basins in the alpine climate, maintenance requirements, and construction and maintenance costs. No monitoring has been performed at these sites to date.

OWP Tasks

• Assisted in Study Planning
• Reviewed Designs of Monitoring Systems

OWP Contacts: Dipen Patel | John Johnston