Stormwater Management

At their meeting of October 27, 2009, the City Council approved the city's participation in the Central Coast Regional Water Quality Control Board (RWQCB) and the Low Impact Development Center's Joint Effort Project for the development of Hydromodification Control Criteria methodology for the Central Coast Region. The council also approved the city's participation in the collaborative program for local municipalities for the development of best management practices (BMPs) for public education, public participation, and pollution prevention.

Finally, the City Council approved the incorporation of additional requirements set forth by the RWQCB into the city's Storm Water Management Plan (SWMP) and authorized the city manager to approve minor modifications to the SWMP, as required by the RWQCB in response to annual reporting and plan implementation.

Storm Water Management Plan
The City of Arroyo Grande's SWMP was approved by the Central Coast RWQCB on December 15, 2009, in accordance with state guidelines for the National Pollutant Discharge Elimination System (NPDES) permit for small municipalities. The permit requires that BMPs, measurable goals and timetables be developed for six minimum control measures (MCMs) included in the SWMP. The MCMs are as follows:
  • Public Education
  • Public Participation
  • Illicit Discharge Detection and Elimination
  • Construction Site Storm Water Runoff Control
  • Post-Construction Storm Water Management
  • Pollution Prevention / Good Housekeeping for Municipal Operations
The SWMP outlines a five-year plan to improve the quality of stormwater through BMPs which are designed to reduce the volume of stormwater runoff into our creeks and streams and to eliminate the discharge of pollutants to the city's stormwater collection system. The approved SWMP will require a new way of doing business for developers, businesses, residents, and the city. The city is currently in the third year of the five year SWMP.

Annual Reporting
The city submitted its second Annual Report of progress toward implementation of the BMPs described in the SWMP in December, 2011. The report documented the activities the city performed in year two (September 15, 2010 - September 14, 2011) to implement the various BMPs.

Countywide Joint Efforts
The city is participating in two countywide joint efforts related to stormwater management. The first is the San Luis Obispo County Partners for Water Quality (the Partners Group) created for the purpose of mutual participation in countywide public education and outreach programs. The Partners Group is made up of city and county staff and other interested stakeholders with meetings held quarterly.

The second joint effort group that the city participates in is the San Luis Obispo Countywide Hydromodification Technical Advisory Committee (HTAC). The HTAC is made up of representatives from San Luis Obispo, Santa Barbara, Santa Cruz, and Monterey counties, and the engineering, development and consulting communities. The HTAC meets monthly for the purpose of developing interim and long-term hydromodification management criteria and low impact design (LID) objectives.

Although the city has begun the implementation of BMPs in all six of the MCMs, the full impact of the measures required for protecting and preserving our watershed have not yet been felt. The design of new development projects is already subject to LID guidelines that will stress reducing stormwater runoff by infiltrating it onsite rather than collecting it in off-site drainage systems.

Post-construction stormwater controls that will treat stormwater pollution at its source are required and an inspection program is being developed to ensure their continued maintenance and operation. Construction sites will be subject to stricter controls on runoff. Improving city procedures for development review and construction site inspections will be necessary.