Urban stormwater management in the City of Pacific Grove

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A watershed-related issue examined by the ENVS 560/L Watershed Systems class at CSUMB.

An example of stormwater discharge through Greenwood Park in Pacific Grove, CA. Image by Fred Watson


Discharge from urban areas, like the city of Pacific Grove, may contain pollutants that flow into coastal waters. Since Pacific Grove is upstream of the Monterey Bay National Marine Sanctuary (MBNMS), an Area of Special Biological Significance (ASBS), they are under pressure to comply with urban stormwater regulatory standards set by the State Water Resources Control Board (SWRCB)[1]. The SWRCB is responsible for permitting and regulating prohibited waste discharges into ASBS under the California Ocean Plan amendments. Direct discharge from municipal separate storm sewer system (MS4s) outfalls into ASBS/MPA receiving waters are listed as 303(d) impaired water bodies under the Clean Water Act (CWA). In response to regulations, the city of Pacific Grove and other regional municipalities formed the Monterey Regional Stormwater Management Program (MRSWMP). Other cities included are: Carmel, Del Rey Oaks, Marina, Monterey, Pacific Grove, Sand City, and Seaside. The MRSWMP has been responsible for obtaining National Pollution Discharge Elimination (NPDES) stormwater permits. One urban stormwater management practice is implemented BMPs with low-impact development strategies to comply with the newly proposed 90% reduction in contaminant load.

Directional stormwater flow in Pacific Grove. Map by: Kirk Post


The City of Pacific Grove, California is located in the northwest portion of the Monterey Peninsula. Pacific Grove contains multiple watersheds, including the Greenwood Park Watershed. Greenwood Park is located in a highly urbanized area and contributes large volumes of stormflow runoff, discharging into the Monterey Bay ASBS. Approximately 43% of the watershed is covered by impervious surfaces and maintains an average slope of 8%, resulting in minimal percolation of seasonal precipitation.

Impervious landcover on the Monterey Peninsula highlighting the Greenwood Park Watershed. Map by: Kirk Post


Many stakeholders are involved in the management of stormwater runoff in Pacific Grove by reducing environmental impacts in areas around Pacific Grove.

Regulatory Background: Laws and Policies

Many laws and policies have been implemented and enforced to reduce pollutants and contaminants being discharged into ASBS off the coast of Pacific Grove.


Federal laws and policies include:

  • United States Environmental Protection Agency (US EPA)
    • Clean Water Act: Amendment Sect:402(p) established framework for stormwater discharge permits and regulations under the National Pollutant Discharge Elimination System (NPDES) permit system.
      • The NPDES permit system under the CWA maintains both Phase I and Phase II municipal Storm drain (MS4s) operators to comply and obtain NPDES permits.
Phase I-As of 1990 permits include municipal separate storm sewer systems (MS4s) defined as medium or large, serving >100,000 people.
Phase II-Beginning in 1999 permits include State’s General Storm Water Permit for Small Municipal Separate Storm Sewer Systems (MS4) comply with NPDES permit components (6). NPDES Phase II program
  • Marine Life Protection Act


State laws and policies include:

  • State Water Resources Control Board (SWRCB)
    • Urban stormwater runoff Cease and Desist order
    • Exception to the California Ocean Plan for Areas of Special Biological Significance Waste Discharge Prohibition for Storm Water and Nonpoint Source Discharges, with Special Protections.[2]
  • Porter-Cologne Act[3]
    • Stormwater discharge monitoring requirements
    • Stormwater management task force
    • Guidance on quantifiable effectiveness of municipal stormwater programs
    • School educational materials required by municipal stormwater permits


Regional laws and policies include:

  • Monterey Regional Storm Water Management Program (MRSWMP)
  • Central Coast Regional Water Quality Control Board (CCRWQCB)
  • Regional Wastewater Pollution Control Agency (MRWPCA)


Local laws and policies include:

  • Cease and Desist from Discharging Waste to Areas of Special Biological Significance (ASBS) in Violation of Prohibitions Prescribed by the State Water Resources Control Board (February 11, 2005)[4]
  • RWQCB requirements directing all cities to develop and implement a set of Best Management Practices (BMPs)
  • City Ordinance
  • Urban Storm Water Quality Management and Discharge Control

Regulatory and Program Timeline[5]

Following is a timeline of events for the State Board’s development of the ASBS Special Protections and the City’s request for an exception:

  • 2004 State Board notifies ASBS dischargers of the requirement to prohibit waste discharges into the ASBS.
  • 2005 Central Coast Regional Water Quality Control Board drafts Cease and Desist Orders (CDO) to require Pacific Grove, Monterey and others to either apply for and receive an exception to the Ocean Plan or cease the discharge of storm water runoff into the ASBS. The CDOs have been held in abeyance while State Board drafts Special Protections and conducts the CEQA review of a General Exception.
  • 2005 State Board requires municipalities and other discharges to apply for exceptions to the Ocean Plan to allow the discharges to continue.
  • 2006 State Board releases initial draft Special Protections to address storm water and

nonpoint source discharges into ASBS.

  • 2006 City of Pacific Grove submits one of twenty-seven ASBS Exception Requests
  • 2007 State Board deems City of Pacific Grove exception request to be complete (see Attachment 3).
  • 2008 State Board issues revised draft Special Protections
  • 2008-2009 Central Coast ASBS jurisdictions develop proposal for a Regional Monitoring Program
  • 2010 State Board issues CEQA Initial Study and Notice of Preparation of an EIR for a General Exception to discharges into ASBS statewide
  • 2011 State Board issues CEQA Draft Program Environmental Impact Report and sets hearings for adoption of the Special Protections (see Attachment 5)
  • 2012 Final version-Exception to the California Ocean Plan for Areas of Special Biological Significance Waste Discharge Prohibition for Storm Water and Nonpoint Source Discharges, with Special Protections.[2]


Water Quality Monitoring and Science

Data Collection Programs

  • Urban Watch Report-The program was initiated in 1997 as a collaborative management and education tool supported by Coastal Watershed Council, the City of Monterey, and the Water Quality
  • Protection Program of the Monterey Bay National Marine Sanctuary


  • National Water Quality Inventory
  • Monitoring of stormwater quality within the City of Pacific Grove is performed by multiple entities including:
    • Citizen Watershed Monitoring Network organizes annual First Flush
    • Urban Watch, and Snapshot monitoring activities for the Monterey region that document stormwater quality conditions for the first storm of the season
    • Monterey Bay Sanctuary Citizen Watershed Monitoring Network (Citizen)[8]
  • Monterey Bay Sanctuary Citizen Watershed Monitoring Network

Management Strategies

The City of Pacific Grove and Monterey County participants in the Monterey Regional Storm Water Management Program have created have established municipality specific contact diagrams to more effectively create and implement BMPs.[9]

Current Overview

The city of Pacific Grove maintained 34 discharge pipes (10-54 inches in diameter) from its Municipal Separate Storm Sewer System (MS4s). Additional city surface runoff from the Pebble Beach watershed flowed into coastal areas within the Monterey Bay National Marine Sanctuary as non-point source runoff. Urban stormwater discharge from 246 point sources was specifically viewed as a source of allochthonous contaminants within the California Ocean Plan. On October 18, 2004, the State Water Board notified municipal stormwater parties to cease stormwater and non-point discharge into ASBS, while obtaining permits no later than May 31, 2006. Permits for special exceptions must be approved by SWRCB, CEQA, and US EPA. On March 16, 2012 Attachment B issued a Final Environmental Impact Report (FEIR). A statewide general exception to the Ocean Plan included implementation of Regional Water Board special protections in permitting for discharges into ASBS. The Ocean Plan states that:

“Waste shall not be discharged to areas designated as being of special biological significance. Discharges shall be located a sufficient distance from such designated areas to assure maintenance of natural water quality conditions in these areas.”

The absolute discharge prohibition in the Ocean Plan is applied unless an “exception” is granted. New regulations within Attachment B specified a 90% reduction in pollutant loading during storm events, for the applicant’s total discharges, and discharges that do not alter receiving water quality outlines within the Final Environmental Impact Report [10]. The City of Pacific Grove has been actively working towards preemptively complying with newly proposed regulatory standards by establishing the Monterey Regional Stormwater Management Program[11], implementing Best Management Practices (BMPs), aided by funding from 2006 State Water Board Proposition 84 Area of Special Biological Significance grant that contains three phases, including dry weather diversion system, Greenwood Park detention wetland (completed by summer of 2014), and Low Impact Development incetives.






  • 2002 Model Urban Runoff Program: A How-To guide for Developing Urban Runoff Programs for Small Municipalities. July 1998 (revised February 2002, by the California Coastal Commission)[15]
  • 2002 Memorandum of Agreement (MOA) for the Monterey Regional Storm Water Pollution Prevention Program[16][11]
  • 2005 CASQA California Ocean Plan, Areas of Special Biological Significance, Waste Discharge Prohibition[17]
  • 2006 Proposition 84 Areas of Special Biological Significance (ASBS) Grant Program(The Safe Drinking Water, Water Quality and Supply, Flood Control, River and Coast Protection Bond Act)[18]
  • 2006 MACTEC Engineering and Consulting, Inc. for Phase III dry weather and stormflow runoff into Pacific Grove area of ASBS.[19]
  • Date unknown Urban Forest Management Plan. By RBF consulting.[20]
  • Annual Reports: Monterey Regional Storm Water Management Program (MRSWMP)
    • Low Impact Development (LID) technologies implemented as Best Management Practices BMPs throughout the watershed.
  • Best Management Practices (BMPs)


  • 2010 Integrated Regional Water Management Plan (IRWMP). Monterey Peninsula, Carmel Bay, and South Monterey Bay Integrated Regional Water Management Regional Acceptance Process Materials[21]
  • 2011 iTree[22]
  • 2011 Report and data on Pacific Grove Stormwater Outfalls[23]
  • 2012 Current Greenwood Park Monitoring by CSUMB[24][25]
  • 2012 (March 19) Request for Proposals (RFP): Design, Environmental Review and Permitting of a Stormwater Treatment System at Greenwood Park[26]


  1. http://www.waterboards.ca.gov/water_issues/programs/stormwater/
  2. 2.0 2.1 http://www.waterboards.ca.gov/water_issues/programs/ocean/asbs/docs/asbs_eir022112clean.pdf
  3. http://www.waterboards.ca.gov/laws_regulations/docs/portercologne.pdf
  4. http://www.waterboards.ca.gov/centralcoast/board_info/agendas/2005/feb/item28/item28_2005_0008_cdo_pg_2_03_05_final.pdf
  5. http://www.ci.pg.ca.us/age/CCO/A-CCO20110302/15b.pdf
  6. http://www.waterboards.ca.gov/centralcoast/board_info/agendas/2005/feb/item28/item28_2005_0008_cdo_pg_2_03_05_final.pdf
  7. http://www.monterey.org/LinkClick.aspx?fileticket=vPF8dkMtHbY%3d&tabid=927&mid=5113&language=en-US
  8. http://montereybay.noaa.gov/monitoringnetwork/about_us.html
  9. http://monterey.org/en-us/departments/planspublicworks/engineering/stormwaterprogram/mrswmp.aspx
  10. http://www.waterboards.ca.gov/board_info/agendas/2012/mar/032012_4cs1.pdf
  11. 11.0 11.1 Monterey Regional Stormwater Management Program http://www.montereysea.org/index.php
  12. http://montereybay.noaa.gov/
  13. Monterey Bay Sanctuary Citizen Watershed Monitoring Network http://montereybay.noaa.gov/monitoringnetwork/pdf/ff2011.pdf
  14. http://sanctuarysimon.org/monterey/sections/waterQuality/project_info.php?projectID=100141&sec=wq
  15. Monterey Bay Sanctuary Citizen Watershed Monitoring Network http://www.co.monterey.ca.us/msea/Literature/Documents/MURP.pdf
  16. Memorandum of Agreement for the Monterey Regional Storm Water Pollution Prevention Program http://www.ci.pg.ca.us/pubworks/mrswmp/MRSWMP_a.pdf
  17. http://waterboards.ca.gov/water_issues/programs/ocean/docs/asbs/wrkshp083105/casqa.pdf
  18. http://www.waterboards.ca.gov/water_issues/programs/grants_loans/asbs/docs/prop84_asbsguidelines.pdf
  19. MACTEC Report
  20. Urban Forest Management Plan. By: RBF consulting http://www.ci.pg.ca.us/pubworks/CC%20Presentation_Final.pdf
  21. Monterey Peninsula, Carmel Bay, and South Monterey Bay Integrated Regional Water Management Regional Acceptance Process Materials http://www.mpwmd.dst.ca.us/Mbay_IRWM/Mbay_IRWM.htm
  22. http://www.ci.pg.ca.us/pubworks/iTree.pdf
  23. http://ccows.csumb.edu/pubs/proj_pubs/2011/ENVS660_PGStormwater/index.htm
  24. Watson, F., Krone-Davis, P., and Smith, J. 2012 in prep. Streamflow gaging at Greenwood Park, Pacific Grove, California: January-April 2012. Report prepared for Monterey Bay Sanctuary Foundation and the City of Pacific Grove. The Watershed Institute, California State University Monterey Bay, Publication No. WI-2012-3. Available from: http://ccows.csumb.edu/pubs/
  25. CSUMB Class ENVS 660: Pugh K, Arenas R, Cubanski P, Lanctot M, Purdy A, Bassett R, Smith J, Hession S, Stoner K, Ashbach R, Alberola G, Jacuzzi N, Watson F. 2011. Stormwater outfall watershed delineation, land cover characteristics, and recommended priorities for monitoring and mitigation in the City of Pacific Grove, California. The Watershed Institute, California State Monterey Bay, Publication No. WI-2011-02, 74 pages. http://ccows.csumb.edu/pubs/reports/CSUMB_ENVS660_ClassReport_PGStormwater_120306.pdf
  26. http://www.ci.pg.ca.us/RFP%20Wetland_GreenwoodPark.pdf



This page may contain student work completed as part of assigned coursework. It may not be accurate. It does not necessary reflect the opinion or policy of CSUMB, its staff, or students.