Difference between revisions of "Urban stormwater management in the Monterey Bay region"

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*[http://www.montereysea.org/docs/program/annual_rpt_year_05/Monterey%20Regional%20Year%205%20Annual%20Report.pdf Year 5] (2010-2011)
*[http://www.montereysea.org/docs/program/annual_rpt_year_05/Monterey%20Regional%20Year%205%20Annual%20Report.pdf Year 5] (2010-2011)
*[http://www.montereysea.org/docs/program/annual_rpt_year_06/Monterey_Regional_Year_6_Annual_Report_final%202.pdf Year 6] (2011-2012)
*[http://www.montereysea.org/docs/program/annual_rpt_year_06/Monterey_Regional_Year_6_Annual_Report_final%202.pdf Year 6] (2011-2012)
*[http://www.montereysea.org/docs/program/annual_rpt_year_07/1%20%20%20MRSWMP%20Annual%20Report%20Year%207%20(2012%20-%202013)%20FINAL%2011-15-13.pdf Year 7] (2012-2013)
===== Annual Reports by City =====
===== Annual Reports by City =====

Latest revision as of 13:07, 29 March 2018

Integrated Regional Water Management Plan (IRWMP) for the Greater Monterey County. Map Provided by Greater Monterey IRWMP [1]


Over the past two decades, urban stormwater management has been gaining the attention of the public and decision makers in the Monterey Bay Region. Storm water management requirements have been grouped into two NPDES permit phases based on city size, per relevant Clean Water Act promulgation beginning in 1990. Cities with large (>250,000) and medium (100,000-250,000) populations were given a Phase I permit, and small populations (10,000 - 100,000) were given Phase II permits.[2] The Phase II cities collectively applied for a General Permit, and are organized under the Monterey Region Storm Water Management Program (MRSWMP). Permits must be renewed every 5 years.

On the Federal level, urban stormwater management is required by National Pollution Discharge Elimination System (NPDES) permitting for managing point source pollution, first instated by the Clean Water Act [3]. Industrial, municipal, and other facilities are all required to obtain permits to discharge waste to surface waters [4]. The State Water Boards provide oversight; California regulates construction, industrial facilities, and municipalities under this system [4].

NPDES Permit Type Applicable to Monterey Bay Region Municipalities

Phase I

Phase I regulations, effective since 1990, require NPDES permits for storm water discharges for certain specific industrial facilities and construction activities, and for “medium” and “large” municipal separate storm sewer systems (MS4s) generally serving populations greater than 100,000. The only Phase I city in the Monterey Bay Region is Salinas.[5]

Phase II

In December 1999, the EPA promulgated more regulations known as the Storm Water Phase II Final Rule for all MS4s with urbanized areas and municipalities with a population base greater than 10,000 with a population density greater than 1,000 persons per square mile, and includes construction sites of 1 to 5 acres.[2] In California, NPDES General Permits for small MS4s are overseen by the Regional Water Quality Control Board (RWQCB) and require the development of a management plans that discuss existing and proposed programs that will protect water quality by reducing or eliminating pollutant runoff from entering local water bodies.

Small MS4s are designated by:

  • Automatically designated by EPA because it is located within an urbanized area,


  • Individually designated by the RWQCB after considering factors such as high population density (1,000 residents per square mile), high growth or potential(growth greater than 25percent between 1990 and 2000 or anticipated growth greater than 25percent over a 10-year period), a significant contributor of pollutants to an interconnected permitted MS4, discharge to sensitive water bodies, and/or a significant contributor of pollutants to waters of the United States.

Phase II requires the implementation of six Minimum Control Measures (MCMs):

  • Public Education and Outreach on Storm Water Impacts
  • Public Involvement/Participation
  • Illicit Discharge Detection and Elimination
  • Construction Site Storm Water Runoff Control
  • Post-Construction Storm Water Management in New Development and Redevelopment
  • Pollution Prevention/Good Housekeeping for Municipal Operations

Each MCM has associated Best Management Practices (BMPs) and Measurable Goals to achieve permit requirements.

The Monterey Region Storm Water Management Plan (MRSWMP)

The purpose of the MRSWMP is to reduce discharge from Municipal Separate Storm Sewer Systems (MS4s) to the “maximum extent practicable,” to protect water quality, and to satisfy the appropriate water quality requirements of the Clean Water Act. It is the organizational framework that connects all the entities under the General Permit, and includes a description and map of the areas under the Program. It also describes the BMPs and Measurable Goals of each entity. [2]

The Monterey Regional Storm Water Mangement Plan Group includes the following entities:

Federal facilities (i.e. the Naval Postgraduate School), school districts, colleges and universities, and miscellaneous entities (i.e. Monterey Peninsula Airport) are excluded from these jurisdictions.

Additional entities ("Coordinating Entities") that coordinate some of their individual SWMP activities under this Program:

  • Monterey Peninsula Unified School District, Pacific Grove Unified School District, and the Carmel Unified School District
  • City of Carmel-by-the-Sea
  • Pebble Beach Co.
MRSWMP Annual Reports
Annual Reports by City

Other Monterey Bay Municipalities Annual Stormwater Reports


Annual Reports


King City

The King City SWMP was revised for final review in 2009 and the first year of the permit will end in early 2010[7]. The plan will have a 5 year implementation period. Over the course of the permit the City will be required to submit annual reports documenting the progress made each year in the form of measurable goals for each best management practice.

Annual Reports:

  • None currently exist


Annual Reports:


Annual Report Confirmations

Santa Cruz County Municipalities

Municipalities in the northern part of Monterey Bay are also involved in stormwater management activities.

Integrated Regional Water Management Plan (IRWMP)[8]

Type of IRWMP entities:

  • government agencies
  • nonprofit organizations
  • educational organizations
  • water service districts
  • private water companies
  • organizations representing:
  • agricultural
  • environmental
  • community interests


  • 1990 Phase I NPDES permitting promulgated by EPA
  • 1998 Monterey Region finishes developing the Model Urban Runoff Program (MURP) to assist small municipalities in developing their own programs for Phase II reqs
  • 1999 Phase II NPDES permitting promulgated by EPA (expands Phase I program)
  • 2000 In March, a Working Group consisting of public works representatives from all MRWPCA member entities decided to apply under a single NPDES General Permit (Phase II only)
  • 2002 A "Memorandum of Agreement for the Monterey Regional Storm Water Pollution Prevention Program" was prepared and executed to create regional organization and commitment to the NPDES permit, although community-level plans are also required; the agreement will terminate when the current NPDES permit expires

Resources at Stake

Common pollutants include pesticides, fertilizers, oils, salt, litter and other debris, and sediment, as well as fecal coliform bacteria resulting from illicit connections between sanitary and storm water sewage systems. These pollutants are a threat to public drinking and recreational water usage, spawning and wildlife habitat, aesthetic values, and can lead to fish kills.

Importantly, there are two areas--Pacific Grove and Carmel Bay-- in the region where stormwater has the potential to carry large pollutant loads into Areas of Special Biological Significance (ASBS). See Urban Discharges to Areas of Special Biological Significance on Monterey Peninsula for more information. One of the MRSWP's goals is to minimize surface runoff pollutants[9] from entering areas of biological significance in the Monterey Bay.


  • California American Water
  • Citizen Watershed Monitoring Network
  • California Coastal Commission
  • Monterey County Service Area 50
  • California State Coastal Conservancy
  • Monterey Peninsula Regional Park District
  • California Department of Fish and Game
  • NOAA Fisheries Service
  • California State University Monterey Bay
  • Pebble Beach Community Service District
  • California State Water Resources Control Board
  • Pebble Beach Company
  • Carmel Area Wastewater District Planning and Conservation League
  • Carmel River Steelhead Association
  • Central Coast Regional Water Quality Control Board
  • Carmel River Watershed Conservancy
  • Resources Conservation District of Monterey County
  • Carmel Unified School District
  • Seaside Basin Watermaster
  • Carmel Valley Association
  • State Department of Parks & Recreation
  • City of Carmel-by-the-Sea
  • Surfrider Foundation
  • City of Del Rey Oaks
  • The Nature Conservancy
  • City of Pacific Grove
  • City of Sand City U.S.
  • Army Corps of Engineers
  • City of Seaside
  • U.S. Fish and Wildlife Serve
  • Monterey Bay National Marine Sanctuary
  • Ventana Wilderness Society

Laws, Policies, and Regulations

The following is a list of laws, policies, and regulations that effect stormwater management:




The tools that are used to help manage stormwater issues are HEC-HMS [10] for hydrologic modeling, and water monitoring instruments to measure discharge at a particular point (preferably at the watershed outlet).


General funding sources for stormwater management exist on a federal, state, and local level. Service fees tend to be most prominent, with an equity-driven, cost-based rate structure that depends on peak discharge, discharge volumes, and contaminant concentrations [11]. Other revenue sources include general revenue appropriations; plan review, development inspection, and special user fees; special assessments; bonding for capital improvements; in-lieu of construction fees; capitalization recovery fees; impact fees; developer extension/latecomer fees; and federal and state grants, loans and cooperative programs.

Future Research

  • Possible Thesis topic: Effectiveness of management efforts
  • Continuous monitoring
  • Effective and preferred Best management practices (BMPs)


  1. IRWMP Maps
  2. 2.0 2.1 2.2 MRSWMP
  3. NPDES Background NPDES Background
  4. 4.0 4.1 Storm Water Management Factsheet
  5. Salinas Stormwater Program
  6. City of Gilroy, City of Morgan Hill and County of Santa Clara SWMP
  7. King City SWMP
  8. Integrated Regional Management Plan for the Greater Monterey County Region (IRWMP)
  9. TMDLs in the Monterey Bay Region of California
  10. Hydrologic Modeling System (HEC-HMS)
  11. Guidance for Municipal Stormwater Funding



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