The Soap Lake floodplain is a natural detention basin in the upper Pajaro River watershed, storing water and reducing peak flows that would otherwise increase flooding in the lower portions of the Pajaro River watershed. The Soap Lake Floodplain Preservation Project (Soap Lake Project) is designed to preserve the natural floodplain characteristics and flood storage capacity through the acquisition of land and flood conservation easements.
The goal of the Soap Lake Project is to protect approximately 9,100 acres of agricultural lands in the upper Pajaro River Watershed, the approximate area inundated by the 100-year flood flows.
The Soap Lake floodplain is a seasonal feature of the watershed that was identified as extremely important for flood protection. Soap Lake is created when significant rain events cause flooding of low-lying areas and flows backup on the Pajaro River upstream of the San Benito River. Approximately 9,100 acres of the relatively flat land straddling the San Benito and Santa Clara County boundary in the Soap Lake area floods during a 100-year storm event. The floodplain acts as a natural control for increased flows from the upper Pajaro River watershed and without the flooding of this area, the downstream flows would increase significantly, impacting the flood vulnerable communities in the Lower Pajaro River Watershed.
The Pajaro River Watershed Flood Prevention Authority (FPA) is implementing the Soap Lake Project to preserve the floodplain attenuation benefits provided by the Soap Lake area. The goal of the Soap Lake Project is to protect approximately 9,100 acres of agricultural lands in the upper Pajaro River Watershed, the approximate area inundated by the 100-year flood flows. The Soap Lake Project is designed to preserve the natural floodplain characteristics through the acquisition of land and flood conservation easements and, where the purchase of an easement is not feasible, the fee title purchase of the property. The FPA is encouraging the floodplain acquisitions by providing grant funds to and partnering with agencies and organizations pursuing acquisitions within the Soap Lake floodplain. Acquisitions have been funded through a Proposition 50 Integrated Regional Water Management Grant from the Department of Water Resources (DWR). The total grant was for approximately $4.1 million, of which, approximately $3.5 million was used for land acquisitions. The FPA used grant funds to support land and easement acquisitions in the Soap Lake Floodplain through the award of grants to reimburse acquisition costs incurred by the participating agencies and organizations. Approximately 4,600 acres in the floodplain have been preserved, in part by the FPA and partner agencies. The FPA continues to pursue additional funding and partnership opportunities to support land and easement acquisitions in the Soap Lake Floodplain.