The Ventura County Watershed Protection District developed a complete watershed model of the Calleguas Creek system, including Revolon Slough, using the Modified Rational Method. Sub-watersheds were carefully digitized; land surface imperviousness was compared to the latest aerial photos, and routing reaches were measured from Rocky Peak to Mugu Lagoon. The majority of watershed sub-areas are less than 100 acres, but in some rural areas, larger sub-areas seemed appropriate. For each sub area, input variables include these parameters: area in acres, time of concentration in minutes, percent effective imperviousness, hydrologic soil type, and rainfall zone with storm frequency.

For additional information, please visit the Calleguas Watershed Management Plan website.

Operations and Maintenance field crews regularly inspect and clear obstructions from the over 200 miles of improved and unimproved channels within the District’s jurisdiction. Each year, thousands of cubic yards of silt and debris are removed from waterways.

District staff must keep debris from clogging flood control channels and reservoirs. Silt is an ongoing by-product of nature. During heavy storms, eroded soils wash into fast-moving creeks. The silt is carried downstream where it settles out in low-lying channels.

Channel Cleanouts are critical to keeping stormwater flowing unimpeded. Water pollution degrades surface waters making them unsafe for drinking, fishing, swimming, and other activities. As authorized by the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution by regulating point sources (pipes or man-made ditches) that discharge pollutants into waters of the United States.


NPDES Cleanout Slide Show

2023 NPDES Channel Cleanout Schedules by Supervisoral District

The Ventura County Sheriff’s Office of Emergency Services (OES), in conjunction with many of the incorporated communities and special districts in the county, is preparing a Regional Hazard Mitigation Plan. The plan will identify the risks posed by natural and human caused disasters, and prioritize ways to reduce disaster impacts. The plan is required under the Disaster Mitigation Act of 2000 as a pre-requisite for receiving certain forms of Federal disaster assistance.

Disasters in Ventura County

As last year’s wildfires demonstrated, Ventura County is highly vulnerable to disasters. In the past ten years alone, Ventura County has received five Presidential disaster declarations for fires, earthquakes, landslides, and flooding. Each year, these hazards cause damage that is not significant enough for a disaster declaration but nonetheless costs county residents, businesses, and taxpayers millions of dollars. The risks posed by these hazards increases as the county’s population continues to grow.

The Disaster Mitigation Act of 2000

In response to the rising cost of responding to, and recovering from, disasters, the President signed the Disaster Mitigation Act of 2000 (Public Law 106-390) on October 30, 2000. Among other initiatives, the law encourages a planning process based on cooperation between state and local authorities, and the community-at-large, to reduce the effects of disasters. The law rewards local and state pre-disaster planning and promotes sustainability as a strategy for disaster resistance. Under the regulations implementing this law, states and local governments must have an approved, adopted hazard mitigation plan in place by November 1, 2004, to continue to be eligible for disaster assistance. The Federal Emergency Management Agency (FEMA) is responsible for reviewing and approving state and local plans.

For more information, please visit the County Regional Hazard Mitigation Plan website.

Ventura County is highly vulnerable to damage from floods due to the geographic location and orographic conditions. Since 1992, there have been five Presidential disaster declarations for flooding in Ventura County. In addition, at least every five years, a flood or flood-related hazard causes damage that is not significant enough for a disaster declaration but, nonetheless, costs county residents, businesses, and taxpayers millions of dollars. The risks posed by these hazards increase as the county’s population continues to grow.

In 1994, Congress authorized the Flood Mitigation Assistance (FMA) Program to provide funding to assist states and localities in implementing measures to reduce or eliminate the risks due to flood hazards. In particular, the FMA Program was designed to reduce the long-term damage to buildings, manufactured homes, and other structures insurable under the National Flood Insurance Program (NFIP). The FMA Program is implemented by the U.S. Department of Homeland Security’s Federal Emergency Management Agency (FEMA) through its state partners.

The goals of the FMA Program are to:

  • Reduce the number of repetitively damaged structures and the associated claims on the National Flood Insurance Program.
  • Encourage long-term, comprehensive mitigation planning.
  • Respond to the need of the communities participating in the NFIP to expand their mitigation activities beyond floodplain development review and permitting.
  • Complement of other Federal and state mitigation programs with similar, long-term mitigation goals.

The FMA Program is a pre-disaster mitigation program made available to states on an annual basis. Although individuals are not eligible for FMA grants directly, their local government may submit an application on their behalf. However, all local jurisdictions that apply for FMA grants must be an active participant in the NFIP.

Two types of FMA grants are available to local communities: planning grants and project grants. Planning grants are awarded to local governments to develop or update a flood mitigation plan that includes: public involvement, coordination with other agencies or organizations, flood hazard area inventory, problem identification, and review of possible mitigation actions. Project grants are awarded to communities that already have a FEMA-approved mitigation plan and want to implement the strategies set forth in the plan to reduce the risk of flood damage to structures insurable under the NFIP. The mitigation of repetitively damaged structures is a high priority

In California, the Governor’s Office of Emergency Services (OES) administers the FMA Program and is responsible for selecting projects for funding throughout the state. The OES then forwards selected applications to FEMA to determine final eligibility.

In 2003, the OES awarded a FMA planning grant to Ventura County to develop a flood mitigation plan. The county, in turn, entered into a Cooperative Agreement with the Ventura County Watershed Protection District (referred to hereafter as the District) to develop the flood mitigation plan because the District has the technical expertise to develop a flood mitigation plan and currently administers the floodplain management program on behalf of the county. The District is preparing the flood mitigation plan in parallel with the multi-jurisdictional hazard mitigation plan for Ventura County, and elements of the flood mitigation plan will be incorporated into the hazard mitigation plan. The completed flood mitigation plan will address planning for risks associated with flooding, post-fire debris flow, and dam failure. It will also address how to mitigate and reduce the number of repetitive loss structures in the county. The flood mitigation plan for the District was prepared with input from Ventura County residents and stakeholders, responsible officials, and URS Corporation (consultants); and with the support of the OES and FEMA.

For more information, please visit the Flood Mitigation Plan for Ventura County.


Ventura River

The mission of the Ventura Countywide Stormwater Quality Management Program is to enhance, protect and preserve water quality in Ventura County water bodies using proactive and innovative ideas for preservation of biodiversity, ecological viability and human health. The goal is to work as a countywide team with public agencies, private enterprise, the environmental community and the general public to locally implement Clean Water Act requirements, balancing the actions taken with social and economic constraints.

Stormwater Monitoring Program

The Stormwater Monitoring Program includes both stormwater management and scientific elements. The collection and analysis of stormwater samples across Ventura County and the analysis and interpretation of the resulting data are the central activities of the Stormwater Monitoring Program. The Stormwater Monitoring Program is currently conducted with the following four major objectives at its focus:

  • Characterizing stormwater discharges from monitoring sites representative of different land uses – industrial, agricultural, and residential
  • Establishing the impact of stormwater discharges on receiving waters by conducting receiving water quality, mass emission, and bioassessment monitoring
  • Identifying pollutant sources based on analysis of monitoring data, inspection of businesses, and investigation of illicit discharges
  • Defining stormwater program effectiveness using data collected before and after implementation of pollution prevention programs
  • For more information, please visit the Ventura Countywide Stormwater Quality Management Program website.

Integrated Pest Management Program for Ventura County Flood Control Facilities (IPMP) provides the objectives and methods for pest management at Ventura County Watershed Protection District facilities.  These facilities include dams, levees, open channels, pipes and culverts.
Report: Integrated Pest Management Program for Ventura County Flood Control Facilities 2016.

The Watershed Protection District completed a 17-month pilot study to determine if raptors could be attracted to levees, reduce burrowing rodent damage, and outperform our rodenticide program.
Study: Raptor Pilot Study for Levee Protection, December 2017