Using Basins to Slow or Prevent Flood Events


The Ventura County Watershed Protection District (VCWPD) has installed or assumed responsibility for more than 50 Debris and Detention Basins to help slow or prevent peak flood events. Many of these basins were built decades ago by other agencies like the Natural Resources Conservation Service (NRSC) to help with flood protection and debris flows during intense storms, so the present VCWPD focus is to now maintain and operate all the various basins regardless of when or who initially built which facility. Thus, whether built by, or transferred to VCWPD, the long term operation and maintenance is an ongoing and often expensive task. With many land use changes over the past 60 years, some of these basins no longer meet their original intended purpose, so VCWPD carefully allocates a sizeable portion of our limited available funds for upkeep and maintenance of all flood control facilities, while always seeking options to reduce annual maintenance costs.

There is also a constant process that evaluates whether these basins are providing the best possible flood protection, and if public funds should be spent to modify, deepen, or enlarge particular basins. Periodic studies of select basins are conducted by the VCWPD Design and Construction (D&C) engineering staff (in conjunction with our in-house Hydrology Section experts) to address the best use of available annual budgets, and whether or not some basins can be abandoned, retrofitted for multi-purpose use, and/or transferred to cities or surrounding property owners for future maintenance and upkeep. Cost-benefit analysis are conducted to guide VCWPD management in the decision making process. So functionality of the basins, hydrologic and hydraulic study/modeling to evaluate the flood control benefits of certain basins, and alternative evaluations for potential multi-purpose use of some basins (such as groundwater recharge to augment extraction well water supplies), helps to guide decision making with respect to the future of many debris and detention basins.


2005 Debris Basin Manual HERE. This is the official document.
Draft 2019 Debris Basin Manual HERE. This document contains all of the basins accepted by the District since 2005, and shows which basins have been obsoleted by the District. Please contact the District if you need official data on any of the new basins at