Urban stormwater management in the City of Watsonville

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The town of Watsonville was incorporated on March 30, 1868. It came under a city charter in 1903. Watsonville is named after Judge John Watson, who came to the valley in 1851. Agriculture and food processing are the main industries in the Pajaro Valley economic structure. Watsonville has a rich agricultural community and the Pajaro Valley is famous for its strawberries , apples, and cut flowers. Nearly 70 percent of the population in Watsonville is Latino [1].


The City Of Watsonville has a storm drain system which directs storm water runoff from streets along gutters and through underground pipes to discharge into the major waterways, and eventually the Monterey Bay. This includes the maintenance of 2000 storm drain inlets, 50 miles of storm water pipeline, and 15 storm water pumps located along Corralitos Creek and the Pajaro River [2]. The system is only designed to control flooding. The storm water is untreated drains flows directly into the ocean.


  • Pajaro River


Regulatory Background

Many laws and policies have been implemented and enforced over the last few decades to reduce pollutants and contaminants being discharged into the Pajaro River, and the Watsonville Slough Complex.


  • National Pollutant Discharge Elimination System(NPDES):This program regulates storm water discharges from municipal storm sewer systems (MS4s), construction areas, and industrial activities. The program focuses on point sources, and operators of point sources are required to receive an NPDES permit before they can discharge. The program aims to prevent and reduce storm water runoff containing harmful pollutants from entering local water bodies.
    • Storm Water Discharges From Municipal Separate Storm Sewer Systems (MS4s) NPDES Permit Program Basics
      • Phase I Issued in 1990 and requires "medium" and "large" cities or certain counties with populations of 100,000 or more to obtain NPDES permit coverage for their storm water discharges MS4s Overview.
      • Phase II Issued in 1999 and requires regulated small MS4s in urbanized areas and small MS4s outside the urbanized areas that are designated by the permitting authority, to obtain NPDES permit coverage for their storm water discharges.Storm Water Phase II Final Rule


  • SWRCB Order No. 2009-0009-DWQ [1] for construction General Permit regulates construction acitivites that disturb one or more acres of soil with required permits for related storm water discharges. The permit requires measures to prevent erosion and reduce sediment and other pollutants in their discharges for the entire construction period.
  • SWRCB Order No. 97-03-DWQ [2] for industrial activities must use the best technology available to reduce pollutants discharged on their premises. In addition, they are required to develop both a storm water pollution prevention plan and a way to monitor their progress.
  • SWRCB Order No. 2003-0005-DWQ Municipal
  • Order No. 2004-0008-DWQ: Aquatic Pesticides
  • Order No. 97-10-DWQ: Discharges to Land By Domestic Wastewater Systems


Water Quality Control Plan for the Central Coastal Basin [3]



  • 1997 Current Industrial Activities Storm Water General Permit
  • 2009 Storm Water Management Plan approved.
  • 2010 City of Watsonville Urban Water Management Plan [4]
  • 2011 Water Quality Control Plan for the Central Coastal Basin

Resources at Stake

A large percent of the population relies on the continued health and vitality of the agricultural industry for their income and livelihood. Storm water problems are a continuous threat to that economic sector due to past scares with E.coli contaminated lettuce in the region.[3] Also, the Watsonville Slough system is comprised of Harkins, Gallighan, Hanson, Struve, and Watsonville Sloughs and drains an area of approximately 50 km2 (13,000 acres).[4] This area contains significant coastal habitats including, salt marsh, brackish and fresh water marsh and the diversity of habitats within this coastal area makes the Watsonville Slough a valuable resource for both coastal plant communities as well as fish and migratory birds.

Management Strategies

  • Low Impact Development Best Management Practices are outlined in the Design Guide.[5] The Design Guide is similar to the hydromodification control standards active in Marin County. This is an interim guide while the City of Watsonville irons out a common hydromodification control standard with the Central Coast Regional Water Quality Control Board. The Design Guidance replaces the City of Watsonville’s Storm Water Land Development Standards.
  • The Storm Water Control Plan provides information on the status of measurable goals, an evaluation of Best Management Practices (BMPs) and their effectiveness and any revisions to BMPs or measurable goals.Cite error: Closing </ref> missing for <ref> tag


  1. Watsonville History
  2. Sewer/Storm Drains
  3. Flynn, Dan. E. coli-Contaminated Lettuce Came from a California LGMA Grower. 2013 Jan 15. www.foodsafetynews.com
  4. Non-Point Source Program - CCA NPS Watershed Assessment for Watsonville Slough
  5. Low Impact Development Best Management Practices - Design Guide



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