Santa Margarita Region MS4 Permit – Pyrethroids Evaluation

Jason E. Uhley, P.E.Jason E. Uhley, P.E.Riverside County Flood Control & Water Riverside County Flood Control & Water

Conservation DistrictConservation District

Santa Margarita Watershed Overview

Permit Requirements

Ongoing Activities

Presentation Outline

Issued within RWQCB jurisdiction on Countywide Basis

Santa Ana Region – Santa Ana RWQCB

Santa Margarita Region – San Diego RWQCB

Whitewater River Region – Colorado RWQCB

Introduction to NPDES MS4 Permits

General Watershed Information

Total Area 740 sq. mi.

Riv. Co. Area 540 sq. mi.

Riv. Co. Population 260,000

Watershed-Wide Non-Urban Land Use

93%

Hydrologic Modification Yes

Average Annual Rainfall 10-12” in valleys

2006-2007 Rainfall 2.6”

Impairments Nutrients, Metals, Turbidity

Santa Margarita

Unique Conditions in the Santa Margarita Watershed

Ephemeral – Receiving waters typically dry

Limited rising groundwater near SMR

No connectivity with urban runoff during dry conditions

Introduction to NPDES MS4 Permits

Issued to municipal operators of MS4 (cities and County)

Regulates stormwater and non-stormwater discharges

Eliminate non-stormwater discharges

Manage stormwater discharges

Santa Margarita NPDES MS4 Permit (SD RWQCB)

County of Riverside

Cities of Temecula, Murrieta and now Wildomar

RCFC&WCD

NPDES MS4 Basics

Permittee StructureRCFC&WCD

Principal Permittee

MurrietaCo-Permittee

TemeculaCo-Permittee

CountyCo-Permittee

Typical Permit Compliance Programs Address:

Legal Authority

Elimination of Illegal Connections/Discharges

Construction Inspection

Business Inspection

Municipal Facility and Activity BMPs

New Development BMPs

Public Education and Outreach

Watershed Monitoring/Annual Reporting

Introduction to NPDES MS4 Permits

Permit Requires Monitoring at Major Receiving Waters

Chemistry

Bioassessment

Toxicity

If Toxicity detected, must conduct TIE

After TIE verifies source, Toxicity Reduction Evaluation required

Basic Monitoring Program

Monitoring Locations

2005-2006 – Persistent Toxicity detected in wet weather flows

2006-2007 – Pyrethroids determined as likely source

2007-2008 - Initiated direct measurements for pyrethroids, TRE

Notes:

1) Have not conducted sediment toxicity tests

2) Toxicity not detected during dry weather, however, receiving waters are

limited to rising groundwater – no connectivity with urban runoff – during dry

conditions

Monitoring Results to Date

Monitoring

TIEs to verify persistence

Pyrethroids testing to assist with source tracking

Regulatory

CDPR Labeling Requirements

CASQA Pesticides Sub-committee

Education and Outreach

HHW/ABOP

Coordinate with Ag Commissioner and UC Cooperative Extension

Require IPM for municipal operations

Point of Sale Outreach

General Education/Outreach

Ongoing Activities

Toxicity Reduction Evaluation

Continued evaluation of persistence and magnitude of toxicity

Literature Review

Source Evaluation and Tracking

Pyrethroids monitoring

Surveys of various representative land uses

Evaluate store sales, Ag. Commissioner, and CDPR data

Develop new BMPs

Public Outreach

Continued lobbying of CDPR, EPA

Ongoing Activities

Annualized Costs $135,525

Toxicity Testing - $20,700

TIE - $69,625

Pyrethroids Monitoring $14,000

TRE Cost - $31,200

BMP Implementation – To Be Determined

Ongoing Activities