Matilija Dam Ecosystem Feasibility Study

Project Status:
26-Jul-2007 -- General Status
Work on the general DDR continues. The Design Agreement was signed in July 2005. The draft general DDR completion has been delayed due to funding limitations and changes in study priorities. In order to accommodate acceleration of various project feature design we have modified our schedule to maximize use of limited funds. The following are some of those items we have initiated or completed.General DDR: Primary purpose is to refine assumptions and recalculate feature characteristics to update project costs and document changes in feature design. Work has been completed to refine the hydraulic and sedimentation models and recalculate require levee heights. Some final review and re-evaluation is planned to fine tune model near Meiners Oaks (we may re-align the proposed levee to avoid vegetation and property use).Environmental coordination has been initiated. A final Biological Opinion has been received from National Marine Fisheries Service in April 2007. The ROD has been signed and the reports have been forwarded to Congress. NEPA has been completed for our Feasibility Phase. We have initiated the cultural resources Programmatic Agreement and section 106 consultation for the well and the programmatic agreement for the entire project.
26-Jul-2007 -- General Status (Cont.)

(Cont.)The sponsor was awarded a state grant to pay for foster park wells and some arundo removal. We have begun efforts to prepare the design (currently 75% complete)for the wells and for arundo removal planning (Sponsor is preparing and coordinating the arundo plan). The wells will be 90% designed and the design will be turned over to the Sponsor to complete the design and prepare the bid package. They will construct the wells. After the arundo plan is approved, the Sponsor will implement the removal plan. This was an included element in the FS but the sponsor was able to get funding before our project is authorized. They will seek credit if the appropriate authorization is passed as law after the fact. Levees: We are initiating the design phase to prepare plans for the Meiners Oaks Levee and Live Oaks Levee. The Casitas Springs Levee, included in the FS, is no longer being considered, as the sponsor has finished raising it since the FS was completed (Dec 04) and is no longer expected to be overtopped during the 100 year event. Robles High Flow Bypass, HFB : We have completed the Value Engineering study to review the High Flow Bypass structure. We have also initiated efforts to construct a physical model of the HFB to test various configurations under various flow conditions.Dam removal: We have initiated effort to review the Slurry system. Arundo removal efforts are being done by the sponsor with the Corps' support and we have initiated efforts to hold a VE study on dam removal phase work.


Comments:
01/30/06 - Click here to voice your comments: http://www.cespl.us/md_comments.htm

Comments And Responses:
01/31/06 - Click here to view the latest responses to you comments:
http://www.spl.usace.army.mil/cms/files/projects/matilija/comments_and_responses.pdf

"Corps Team Wins Planning Award: 08/11/05 - The Matilija Project Delivery Team won the the 2004 Outstanding Planning Achievement Award for its Matilija Dam Ecosystem Restoration Feasibility Study. Read more about the award in this news release. (Click Here)"

Soundclip: 11/24/04 - Dams on California's coastal rivers contribute to a shortage of sand on beaches. The Corps is working together with environmentalists and other government officials to remove one such dam so that sand can flow down this coastal river and fish can swim up it. KQED-Radio's California Report special, "Coastal Conflicts," talks with LA District study manager Jon Vivanti about the proposed removal of Matilija Dam.

Requires RealAudio Player:
http://www.kqed.org/.stream/real/radio/tcrmag/2004/11/2004-11-12e-tcrmag.rm.ram

Background

Matilija Dam was constructed by the Ventura County Watershed Protection District (formerly the Ventura County Flood Control District) in 1947 to provide a water supply for local agriculture needs and to offer limited flood protection for downstream communities. Large volumes of sediment quickly began to accumulate behind the dam, eventually leaving only a small, shallow reservoir, now estimated to hold only seven percent of its original capacity. The approximately six million cubic yards of trapped sediment cripples Matilija Dam’s water storage capacity and undermines its ability to provide flood protection. The dam blocks endangered steelhead trout from reaching prime spawning and rearing habitat. It further prevents the natural flow of sediments from the mountains to the ocean, depriving Ventura County beaches of much-needed sand.

In 1999 an effort was launched to assess the viability of removing the dam and restoring the ecosystem. Federal, state and local officials, along with non-governmental organizations and community members, formulated a plan to remove the dam and sediment, restore the ecosystem and mitigate potential impacts of the project. The five-year study resulted in seven alternatives—six requiring action and one requiring no action.

The Matilija Dam Ecosystem Restoration Feasibility Study is one of the largest dam removal studies in the country, and one of the largest ecosystem restoration studies undertaken by the Corps of Engineers west of the Mississippi River. The study focuses on ecosystem restoration in the Ventura River Watershed to benefit native fish and wildlife of the Ventura River and Matilija Creek in the vicinity of Matilija Dam, and improvement to the natural hydrologic and sediment transport regime to support coastal beach sand replenishment from the Ventura River.

The recommended plan includes full dam removal in one phase. Portions of the trapped sediment would be removed by slurry line to a downstream disposal site, with the remaining sediment to be contoured to restore a fish passage channel, allowing storms to naturally erode sediments downstream. The process of returning the river to pre-dam conditions will increase the flooding risk to infrastructure developed along the river corridor since construction of the dam. The recommended plan includes features to mitigate the induced flood risk by removing structures, replacing a bridge and raising and extending downstream levees. The removal of the dam will also cause impacts to downstream water supply facilities. A sediment bypass facility is proposed to reduce impacts to the Robles Diversion and Lake Casitas facilities, while construction of two ground water wells at Foster Park is included to reduce impacts to City of Ventura facilities.

The recommended plan also includes the removal of exotic and invasive plant species and the implementation of recreational trails and interpretive centers.

The cost of the recommended plan is estimated to be $110 million, with the federal cost share at 65 percent.

The schedule for project implementation assumes conditional authorization in the proposed Water Resources Development Act of 2004, no later than the end of 2004. After project authorization, the project would be eligible for construction funding consideration in the President’s budget. Once federal funds are appropriated, the Corps of Engineers and the non-federal sponsor would enter into a project cooperation agreement, which defines responsibilities for implementing, operating and maintaining the project.


Study Participants

Congressional Representative(s)
     Rep. Elton Gallegly (R-23)

Federal Agencies
     U. S. Fish and Wildlife Service
     U. S. Geological survey
     U. S. Forest Service, Los Padres National Forest
     U. S. Bureau of Reclamation
     National Marine Fisheries Service
     National Park Service
     National Fish and Wildlife Foundation

State Agencies
     California Coastal Conservancy
     California Department of Fish and Game
     California Regional Water Quality Control Board
     County of Ventura Agencies
     County Board of Supervisors
     Public Works
     Flood Control Department
     Government Affairs
     Solid Waste Management Department
     Casitas Municipal Water District

City Governments
     Ventura
     Oxnard
     Ojai
     Port Hueneme

Local Committees/Groups
     Matilija Coalition
     Friends of the Ventura River
     Matilija Environmental Science Area
     American Rivers
     Surfrider Foundation, Ventura Chapter
     Southern California Wetlands Recovery Project
     Fixing Stream Habitats Technical Assistance Program
     BEACON
     California Trout
     Aspen Environmental Group

Universities
     University of California Cooperative Extension
     California State University, Northridge


Frequently Asked Questions

Q1. What is the significance of the Matilija Dam removal project?
A1. This is one of the largest dams in the nation that is being considered for removal. The aging Matilija Dam provides little remaining water storage benefits and virtually no flood control benefits due to nearly 6 million cubic yards of sediment that has deposited behind the dam.

Dam removal will restore the natural flow regime and sediment transport from the Matilija Canyon to the Ventura River and shoreline area, and restore connectivity to upstream and downstream habitats for many fish and wildlife species. Over 17 miles of pristine steelhead spawning and juvenile rearing habitat in the Los Padres National Forest will once again become accessible after more than 55 years of blockage, doubling the amount of river miles currently available for fish passage. This project is particularly important for its potential contribution to the recovery of the Southern steelhead trout population, a federally listed endangered species. The project helps to replenish eroded segments of the river system where up to 10 feet of erosion has occurred since the construction of the dam, and benefits beach nourishment. Recreational opportunities are also being pursued, with new trails designed to link existing trail systems in the Ventura River valley to the Matilija Wilderness area in the Los Padres National Forest.

Q2. What does this project mean to the Corps?
A2. This is the first Corps of Engineers dam removal study of this scope and scale for the nation and sets a precedent for the Corps for future large-scale dam removal studies. There is continued interest in the Corps becoming more involved in studies of this nature in the future due to pressure from environmental groups to have federal involvement in these studies and projects. A recent American Rivers press release estimates that 60 dams in 15 states are scheduled for removal in 2004.

Q3. What is the preferred method of removal?
A3. There is not a specific method identified to remove the dam, however, the use of explosives is the most likely means currently identified. Other methods include diamond wire cutting, expansive chemicals, and hoe-ram. All of these methods were investigated in a previous study.
The removal and recontouring of nearly 6 million cubic yards of sediment trapped behind the dam will be addressed by a combination of mechanical (using a slurry pipeline) and natural erosion. Two million cubic yards of fine-grained materials (silts) will be fluidized with water and transported via a pipeline to several disposal areas located downstream. The remaining 4 million cubic yards will be placed in temporary sediment storage sites constructed around a 100-ft wide meandering channel (for fish passage). These stored sediments will erode during storm events and transported downstream.

Q4. How do you protect downstream water supply/diversion operations?
A4. Some of the sediment storage sites, which contain fines mixed with coarser grained material, will be protected with soil cement revetment to protect against erosion during more frequent storms (less than the 10-yr storm, < 12,500 cu ft/sec). This ensures that downstream turbidity in the water remains about the same for the project when compared to existing conditions. As portions of the trapped sediments are eroded downstream over time, the soil cement revetment will be removed in stages. Complete evacuation of trapped sediment is estimated to occur within 20 years.

Other measures include a high-flow bypass (radial gates) at the Robles Diversion Dam, 2 miles downstream, 2 wells at Foster Park, and a desilting basin betterment (paid for by the Sponsor) for waters diverted through the Robles Canal to Lake Casitas.

Q5. How did we reach this determination (for the Recommended Plan)?
A5. Through an extensive plan formulation process that included input from the Sponsor (Ventura County Watershed Protection District), the public, resource agencies, water agencies, and multiple environmental groups. Many alternatives were considered to address problems and the planning objectives for the study. The recommended plan maximizes the Ventura River ecosystem restoration benefits, while providing flood protection, continued water diversion operations and recreation.

Q6. Why did we select this method (of dam removal)?
A6. The method will be selected during the plans and specifications phase.

Q7. What are the challenges with implementing this method (of dam removal)?
A7. Assuming that explosives will be the selected method, some of the key considerations will be identifying the window in which blasting is allowed and collecting, hauling, and disposing of the blasted material.

Q8. What are the associated costs of the removal project?
A8. There are many separate features that are part of the project and contribute to the total cost. These include dam removal ($25M), elevating or constructing levees and floodwalls ($9M), modifying bridges ($10M), building a high-flow sediment by-pass ($7M), installing slurry lines and disposal area dikes ($29M), removing Arundo Donax, an invasive plant species ($9M), contouring remaining sediments upstream of the dam’s current location ($8M), preparing recreational trails ($1M), and creating a desilting facility for assurance that water can be diverted to lake Casitas ($6M) [Dollars are rounded in millions].

Q9. What is the cost share?
A9. All costs associated with ecosystem restoration will be cost shared 65 percent Federal and 35 percent non-Federal. Recreation components will be cost share 50/50. Currently, the desilting facility is identified as a feature that will be a 100 percent non-Federal cost.

Q10. Who will do the work?
A10. The U.S. Army Corps of Engineers will be responsible to complete the detailed design for the project, including the preparation of Plans and Specifications, in close coordination with the Ventura County Watershed Protection District. We will continue coordination with the numerous governmental organizations, agencies, and interest groups through the plans and specification phase.

After the design phase, the U.S. Army Corps of Engineers will be responsible for administering the construction contracts. A contractor will be selected after the plans and specifications are complete and a contract is executed with the Sponsor (Project Cooperation Agreement). The Ventura County Watershed Protection District will provide required lands and easements.

Q11. What is the timeline?
A11. The current estimated timeline is:

Milestone Date
     Initiate Plans and Specifications January 2005
     Complete Plans and Specifications August 2007
     Initiate Construction April 2008
     Complete Construction October 2011
     Complete Monitoring and Adaptive Management December 2016

Photos (Taken by Jay Field)

The Draft Report on the Matilija Dam Ecosystem Restoration Feasibility Study recommends removing the dam to free the reservoir of some six million cubic yards of trapped sediment. The project will restore a fish passage channel and allow the natural flow of sediment to support coastal beach sand replenishment from the Ventura River.


USACE Study Manager, Jon Vivanti (left), discusses the Matilija Dam removal project with KCAL-TV reporter Mark Coogan during a media visit to the dam near Ojai July 28.





Colonel Dave Turk, LA District Acting Commander, briefs the public at a meeting held to solicit comments on the release of the Matilija Dam Ecosystem Restoration Feasibility Study July 28 in Ventura County.




Ventura County Supervisor Steve Bennett thanks the plan formulation team for their work in drafting the Matilija Dam Ecosystem Restoration Feasibility Study at a public meeting July 28 in the county Hall of Administration.




Map


Related Links
http://matilijadam.org


Past Events

07/28/04 - Board of Supervisor Meeting Video Broadcasting of Matilija courtest of Ventura County - Windows Media File

Technical Documents

07/15/04 - Environmental Impact Statement / Environmental Impact Report are available at Matilija Dam Projects Website - http://matilijadam.org/index.htm

Contacts:

Study Manager
Jonathan Vivanti
(213) 452-3809
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Project Manager:
Darrell Buxton
(213) 452-4007
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Public Affairs Officer:
Jay Field (213) 452-3920
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Comments:

Click here to voice your comments: http://www.cespl.us/md_comments.htm