Orientation Information:
Watershed Assessment and Monitoring
Introduction
Watershed Assessment and Monitoring (WAM) is a key component of the San Mateo
Countywide Water Pollution Prevention Program (Program). The general goals of the WAM
component are to:

characterize creek function, health and water
quality conditions in representative watersheds in
San Mateo County and evaluate potential
stormwater runoff impacts;

develop plans to address specific pollutants of
concern (POC) associated with stormwater runoff
such as mercury and polychlorinated biphenyls
(PCBs) and perform related special studies (e.g., to
identify POC sources); and

evaluate long-term trends in water quality and thereby inform the Program’s efforts to
improve the effectiveness of its Best Management Practices (BMPs) to prevent or
reduce stormwater runoff impacts.
The Program focuses on using integrative tools such as creek walks and bioassessments to
characterize creek condition. The monitored creeks are typically receiving waters for
stormwater discharges from municipal storm drain systems.1 The Program also participates in
1
Direct monitoring of stormwater runoff (e.g., at stormwater outfalls) is considered impractical at this time due to
the inherent difficulties in obtaining statistically representative samples. These difficulties include the large
number of discharge points, the high spatial and temporal variability in stormwater runoff pollutant
concentrations, the unpredictable and intermittent nature of storm events, and the variability in flows.
D:\687295770.doc
1
regional collaborative efforts that develop information needed to improve water quality in San
Francisco Bay and watersheds throughout the Bay Area.
Unlike other Program components, all WAM-related activities are implemented by the
countywide Program for the benefit of its municipalities. Although the Program's
municipalities are not responsible for implementing WAM component tasks, municipal staff
may assist with WAM component projects in their jurisdiction. There are no Performance
Standards for WAM component activities. The WAM Subcommittee meets approximately
every other month to plan and oversee implementation of this component’s activities. The
subcommittee also takes an annual field trip to a project location.
NPDES Permit Requirements
The Program's National Pollutant Discharge Elimination System (NPDES) permit formerly
included Provision C.8 - Monitoring Program. Provision C.8 specified that the Program
prepare an annual Monitoring Program Plan with watershed monitoring activities and special
studies to determine BMP effectiveness or pollutant impacts. A new Monitoring Program Plan
was developed and implemented each year by the WAM Subcommittee, allowing the Program
to respond to previous years' monitoring results, regional developments, and the general
evolution in monitoring techniques. However, a November 2003 court order that resulted
from a Baykeeper lawsuit required that the Program's NPDES permit specify monitoring types,
intervals and frequencies, and that any changes to the Stormwater Management Plan (such as
developing a new annual Monitoring Program Plan) are changes to the permit and are subject
to a public notice and comment period. In response, the Program's NPDES permit was
amended in July 2004 to remove Provision C.8 and adopt the last Monitoring Program Plan
prepared by the Program, which covered WAM component activities through the end of FY
2004/05, but no further. As a result, the Program has not had any monitoring-related permit
requirements since July 2005, but since that time the WAM Subcommittee has continued
implementing similar and logical follow-up monitoring activities to past years.
WAM Component Activities
The WAM Subcommittee selects activities that are
consistent with previous NPDES permit requirements, the
Program's Stormwater Management Plan (November 2003
version), available budget, monitoring activities by other
Bay Area municipal stormwater programs, and regional
monitoring programs. The monitoring locations selected
D:\687295770.doc
2
are generally within representative urban watersheds in San Mateo County.
Typical activities include:

Performing creek walks using the Unified Stream Assessment (USA) protocol, which
employs visual observations to provide an overall picture of the condition and features
of creek channels and riparian corridors.

Collecting screening-level biological, physical and chemical water quality data from
creeks. These data are often referred to as "environmental indicators" that characterize
creek aquatic ecosystem health and water quality conditions. Field activities include
benthic macroinvertebrate (BMI) bioassessments,
field instrument probe measurements (e.g., pH and
dissolved oxygen), and collecting grab water samples
for toxicity screening and chemical analysis.2

Assessing levels and types of trash in creeks using the
Rapid Trash Assessment protocol developed by staff
from the California Regional Water Quality Control
Board, San Francisco Bay Region (Regional Water Board) and modified for stormwater
management programs by the Santa Clara Valley stormwater program.3

Developing plans to address POC (e.g., PCBs, mercury, pesticides, and trash)4 and
perform related special studies, such as case studies to determine sources of PCBs to
urban runoff.5 The Program's POC-related work is coordinated with and assists the
Total Maximum Daily Load (TMDL)6 cleanup plans under development by the Regional
Water Board.
For an example of a report on a screening-level creek monitoring program see Water Quality Screening in the
Cordilleras Creek Watershed in San Mateo County, California, prepared for SMCWPPP by EOA, Inc., May 2007.
3For an example of a report on a trash assessment study see Pilot Study to Identify Trash Sources and Management
Measures at an In-stream Trash Accumulation Area, San Mateo County, California, prepared for STOPPP by
EOA, Inc., August 2005.
4For an example of a plan addressing POC see Pollutant Prevention and Control Measures Plan, prepared for
STOPPP by EOA, Inc., June 29, 2001, revised January 2004.
5For an example of a report on a POC-related special study see Case Study Investigating Elevated Levels of PCBs
in Storm Drain Sediments in the Pulgas Creek Pump Station Drainage, San Carlos, California, prepared for
STOPPP by EOA, Inc., June 2003.
2
6
A TMDL is a cleanup plan for a water body impaired by one or more POC. TMDLs examine water quality
problems, identify sources of pollutants, and specify actions to restore water quality.
D:\687295770.doc
3

Participating in collaborative regional water quality programs, including the Bay Area
Macroinvertebrate Bioassessment Information Network (BAMBI) and the San Francisco
Estuary Regional Monitoring Program (RMP). BAMBI is assisting Bay Area municipal
stormwater programs to refine and standardize BMI bioassessment protocols,
coordinate bioassessment work in the region, and manage and interpret bioassessment
data (see http://cleanwaterprogram.org/bambi_home/index.htm). The RMP monitors
pollutant concentrations in water, sediments, and fish and shellfish tissue in San
Francisco Bay. A major goal is to provide information on how pollutant concentrations
in the Bay are responding to management measures (see www.sfei.org/rmp/index.html).
Municipal Regional Permit and WAM Activities
The Bay Area Phase I municipal stormwater NPDES permits are being reissued as one
Municipal Regional Permit (MRP). The MRP will replace the Program's current NPDES
permit and the other Bay Area Phase I permits. A Tentative Order for the MRP was released
for public comment in December 2007. Similar to previous draft versions of the MRP, the
WAM-related provisions in the Tentative Order are much more prescriptive and extensive
than the requirements in the Program's former NPDES permit. If adopted, the Tentative
Order would expand the level of implementation of the Program's current WAM component
activities and require numerous new activities, including bacterial indicator monitoring,
pollutant and toxicity testing of creek bed sediments, toxicity identification evaluations,
geomorphologic studies, pump station investigations, and loading and source analysis studies
for numerous pollutants. The Program has requested clarification regarding how these very
extensive proposed requirements would lead to improvements in water quality. Other Bay
Area stormwater management agencies have expressed similar concerns. A hearing to take
testimony from the public on the Tentative Order took place in March 2008, but it is unclear
when the MRP will be adopted and what final form its water quality monitoring provisions
will take.
On a positive note, adoption of the MRP would provide an opportunity for increased
coordination and collaboration among Bay Area watershed assessment programs, including
municipal stormwater programs. This new collaborative organization, tentatively designated
the Regional Monitoring Collaborative (RMC), would lead to improved cost-effectiveness of all
of the participating programs through improved knowledge sharing and economies of scale.
Program staff is participating in the planning of the RMC, which is at a very early stage.
D:\687295770.doc
4