Runoff Discharge Characterization
Description
Monitoring and characterization of runoff discharges are
often required to effectively understand and address
stormwater impacts.
Experience
-
Caltrans Statewide Discharge
Characterization Study
-
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
-
Caltrans Tahoe Highway Runoff
Characterization Study
-
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
-
Caltrans Areas of Special Biological
Significance Study
-
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
-
Caltrans Monitoring and Research Program
Data Summary Report
-
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
-
Caltrans Construction Sites Runoff
Characterization Study
-
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
-
Caltrans Aquatic Toxicity
Testing
-
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
