Prior to the removal of Matilija Dam a variety of downstream facilities must be upgraded to accommodate anticipated changes in sediment transport and flow elevations. These upgrades include modifications to bridges, levees, and water diversion structures along with the acquisition of lands, easements and rights of way from willing sellers.
- Santa Ana Boulevard Bridge. The old Santa Ana Boulevard Bridge was seismically deficient and served as a major bottleneck in the Ventura River floodplain. The new, wider, longer and taller replacement bridge – substantially complete by the end of October 2022 – will enhance sediment transport, reduce the need for maintenance after major storm events, and improve migration up and down the Ventura River for the federally-endangered southern California steelhead.
- Camino Cielo Bridge. The current river crossing at Camino Cielo requires reconstruction following major storm events to repair damage and restore access for local residents. A new bridge will eliminate this recurring problem, improve steelhead migration, and avoid negative impacts from increased sediment flows during and after Matilija Dam removal.
- Robles Diversion. Anticipated upgrades to this facility will improve sediment management, maintenance and fish passage under current and future conditions, and will address challenges that are currently impacting water supply reliability by enabling surface water diversions at critical times when flows in the river are sufficient.
- Flood Protection. The community of Meiners Oaks immediately downstream of the Robles Diversion currently lacks adequate flood protection, and will benefit from a new levee and/or other measures to accommodate both current and future river and sediment flows. The existing Live Oak Acres and Casitas Springs levees do not currently meet FEMA standards, and will be upgraded to protect adjacent communities from significant risks to life and property under current and future conditions.
- Local Water Supplies. A variety of local water supply alternatives will also be developed and implemented prior to dam removal – or as adaptive management measures – to address the concerns of downstream water supply agencies regarding reduced groundwater recharge due to increased sediment flows.
- Real Estate and Utilities. Acquiring lands, easements and rights of way from willing sellers together with associated utility relocations will support the components outlined above, protect critical floodplain habitat, and enhance recreational opportunities all along the Ventura River.
When all of the above have been completed, accumulated sediment will be flushed from Matilija Reservoir during a major storm event using two new orifices at the base of Matilija Dam, with dam removal to follow. Other core elements of the Project include the design and implementation of long-term monitoring and adaptive management plans, recreation and stewardship plans, and overall program management.
