Matilija Dam Ecosystem Restoration Project

VENTURA COUNTY, CALIFORNIA

Facts and History

Matilija Dam Facts
Location	15.6 miles from the ocean
Owner	Ventura County Watershed Protection District (VCWPD)
Date Constructed	1947
Purpose	Water supply and flood control
Preconstruction estimated cost	$682,000
Actual total dam cost	~$4 million
Constructed height	198 feet (1,125 elevation)
Current height	168 feet (1,095 elevation) (notched in 1965, 1977)
Width	620 feet
Thickness	8 feet at crest, 35 feet at base
Reservoir Capacity: Design	7,018 acre feet
Reservoir Capacity: After notching	3,800 acre feet (excluding sedimentation losses)
Reservoir Capacity: Current	Less than 500 acre feet (combined notching & sedimentation losses)
Reservoir Capacity: Projected	Zero capacity by 2020
Original Reservoir Area	126.8 acres
Drainage area of Matilija Creek above dam site	55 square miles
Original Spillway Capacity	60,000 cubic feet per second at water elevation 1,137 feet

Matilija Dam History
Prior to 1940	Viable steelhead/salmon population (over 5,000) and other wildlife/natural resources
1941	Corps of Engineers Study - concludes that Matilija would not provide adequate benefits to be cost effective for flood control & water supply
1945	County Bond issued passed - cost for Matilija to be $682,000
1946	June 18 - Construction begins
1947	Mr. Harold E. Burket, architect, warns County Supervisors of alkali-reactive aggregate
1948	March 14 - Dam completed - Report estimated 39 years before siltation would eliminate capacity - County sued engineers for cost overruns and lost
1949	Major fish kill behind dam due to stagnant/hot water
1952	Reservoir filled
1959	Casitas Municipal Water District assumes responsibility of dam
1964	Bechtel Corp. Safety study condemns dam and presents removal as an option
1965	Bechtel Corp. estimates dam removal cost at $300,000 - County elects to notch dam (remove a section 30 feet deep and 285 feet wide) to reduce reservoir capacity to 65% to relieve strain and allow dam to remain in place
1973	Study on littoral processes (Bickel) highlights impact to beaches - USFS estimates sediment contribution of Matilija's dammed watershed to be 116,000 cubic yards per year
1978	Dam notched second time (358 feet wide)
1998	County resolves to remove dam - study begins on dam removal
2000	Bureau of Reclamation - Appraisal Study - Secretary of the Interior Bruce Babbitt visits demonstration project
2001	Initiated the Matilija Dam Ecosystem Restoration Study between the Ventura County Watershed Protection District and the US Army Corps of Engineers
2004	Consensus on preferred project points by all stakeholders
2004	Completed Feasibility Study
2004	Ventura County Board of Supervisors approved the Final EIR/EIS
2004	US Army Corps of Engineers Chief's Report sent to Assistant Secretary of the Army
2005	Initiated the Design Phase of the Matilija Dam Ecosystem Restoration Project between the Ventura County Watershed Protection District and the US Army Corps of Engineers