Runoff Discharge Characterization

Over 100 sites were monitored to characterize stormwater discharges from Caltrans facilities throughout California. Stormwater runoff from the following types of facilities was monitored: highways, rest areas, maintenance yards, park & ride lots, inspection/weigh stations, construction sites, and toll plaza sites. Runoff from all sites was analyzed for a wide range of water quality parameters.

OWP Tasks

• Technical Assistance and Planning

Report/Study Link: Caltrans Statewide Discharge Characterization Study
OWP Contacts: Kevin Murphy

The purpose of this study was to characterize the stormwater runoff from highway sites in the Lake Tahoe Basin. Runoff from six sites during multiple storms was analyzed for a wide range of water quality parameters. In addition, the treatment performance of double-barrel sand traps was evaluated.

OWP Tasks

• Technical Assistance and Planning

Report/Study Link: Caltrans Tahoe Highway Runoff Characterization Study
OWP Contacts: Kevin Murphy

An ASBS is defined in the California Ocean Plan as a coastal marine area that requires protection of species or biological communities to the extent that alteration of natural water quality is undesirable. The ASBS study characterized stormwater runoff from Caltrans highways that discharges to ASBSs on the California coast. This project also included several natural streams that discharge into or near ASBSs in order to compare the water quality of Caltrans stormwater runoff to natural, unimpacted runoff in these areas.

OWP Tasks

• Assisted in Study Planning
• Conducted Historical Review of Caltrans Stormwater Monitoring Data
• Assisted with Development of Sampling Method
• Assisted in Writing Project Study Plan
• Provided Monitoring Coordination and Assistance
• Provided Review of Project Deliverables and Data Evaluation

Report/Study Link: California Transportation Commission Presentation on Areas of Special Biological Significance (ASBS)
OWP Contacts: Tod Granicher

Every year, Caltrans submits a report to the State Water Resources Control Board that discusses steps that have been taken during the previous year to comply with the department's NPDES permit. This report includes a summary of all stormwater data produced during the previous storm season. Statistics reported in this document are generated by processing the raw analytical data using the Caltrans Data Analysis Tool. Data are presented in tabular format grouped by monitoring site.

OWP Tasks

• Compiled and Organized Analytical Data
• Processed Data Using Caltrans Data Analysis Tool
• Produced the Report

Report/Study Link: Caltrans Monitoring and Research Program Data Summary Report
OWP Contacts: Tod Granicher

A sampling study was conducted to develop a baseline set of construction site stormwater quality concentrations. During the four-year study, 120 storm events were monitored at 27 sites. Sites were selected to represent a wide range of typical Caltrans construction activities, geographic areas, and hydrometeorologic conditions as well as other site-specific conditions.

OWP Tasks

• Technical Assistance and Planning

Report/Study Link: Caltrans Construction Sites Runoff Characterization Study
OWP Contacts: Kevin Murphy

Toxicity testing was conducted as part of a number of Caltrans studies in which effluent from treatment BMPs was discharged into receiving waters. EPA three-species bioassays (fathead minnow, water flea, and algae) were conducted, as wells as a 96-hour bioassay for rainbow trout.

OWP Tasks

• Assisted in Study Planning
• Provided Technical Assistance During Toxicity Tests
• Assessed Study Results
• Reviewed Study Reports

OWP Contacts: Dipen Patel | Tod Granicher | John Johnston