Ventura River Watershed

Existing conditions:

The Ventura River watershed encompasses 228 square miles, and is 31 miles long. Its two principal tributaries are San Antonio Creek from the east and Coyote Creek from the west. The annual average flow of the Ventura River is 13,600 acre-feet. It is a highly fluctuating, intermittent stream, running usually only in the winter month's "wet season." The area averages 14 inches of precipitation per year, with ranges varying from 5 to 40 inches. The Ventura River ecosystem supports 23 species of special concern.

Completed in 1959, Casitas Dam is the key component of the Ventura River Project. Casitas Dam is located on Coyote Creek about 2 miles above the junction of the creek and the Ventura River. Robles Diversion Dam is located on the Ventura River about 1.5 miles downstream from the confluence of Matilija Creek and North Fork Matilija Creek. The structure is rockfilled with a timber cutoff wall and a rolled earth core. The dam diverts water into the headworks of the Robles-Casitas Canal.

Robles-Casitas Canal carries water from Robles Diversion Dam to Lake Casitas. The canal is about 4.5 miles long with a capacity of 500 cubic feet per second. There are 4.5 miles of concrete canal and 0.9 mile of 78-inch reinforced concrete pipe, called the Robles-Casitas Diversion Conduit.

In addition to the steelhead, species found along the river include the California condor, California red-legged frog, and California Brown pelican. The major issue within this watershed is the dramatic historical decline of the southern steelhead, which is an indication of the general health of the aquatic ecosystem. More than 5,000 steelhead formerly migrated up the river and Matilija Creek before the dam was built in 1948. Now, less than 100 fish make their way up the river. The dam blocks access to more than 20 miles of some of the best remaining steelhead habitat in southern California.

Much of the upper parts of the watershed are protected as part of the Matilija Wilderness. Removal of Matilija Dam would provide fish passage to historic breeding waters in the upper watershed, and greatly enhance the opportunities for restored habitat for many other species of concern.

Description of Watershed Resources:

Area: 173629.76 acres

Naturally Occurring Waterways: 461.12 miles

Percentage of Free Flowing River Miles: 92 %

Percentage of River Miles in Protected Lands: 11 %

Protected Lands: 12 %

Number of Dams: 6

Number of Selected Watershed Projects: 4

Number of Stream Crossings: 559

Near-Stream Roads: 254.02 miles

Average Precipitation per Year: 25.68 inches

Percentage Area above 15% Slope: 41.43 %

Number of CalWater Units: 21

WBS TMDL Rivers 7

Number of Special Status Species: 6

Anadromous Fish:

Small numbers of adult steelhead have been reported in most years. Robles Diversion Dam (1958) diverts water to Casitas Reservoir on Coyote Creek, and causes de-watering of the lower river and blocks steelhead migration. Above the Diversion Dam, riparian vegetation is abundant with good spawning and rearing habitat. Habitat just below the Diversion Dam is generally poor. Further downstream at Casitas Springs ("The Narrows") is very good habitat with thick riparian cover, abundant spawning areas and perennial flows present.

The Matilija Dam (constructed in 1948) is located 16.2 miles upstream. Access to almost all of Matilija Creek is blocked by Matilija Dam (1948). Below the dam, spawning habitat is scoured and poor but rearing habitat is fair due to constant surface flow. This creek is considered the key to restoring steelhead in Ventura system. Many of the tributaries of the Matilija Creek would provide suitable habitat if the dam is removed (e.g, Murrieta Creek, Old Man Canyon Creek, Upper North Fork Matilija Creek).

Status of Watershed Planning Efforts:

The Ventura River Watershed Planning effort started in 1996 and has received funding from the Coastal Conservancy. The project targets the creation of a watershed management plan for the Ventura River watershed that can provide a framework for dealing with a wide range of issues on public and private lands. The plan will also tie together a number of on-going, separate resource management programs (e.g., estuary restoration, steelhead management, recreation trail, among others). The purpose of the effort is to develop a comprehensive watershed management plan for the Ventura River watershed.

Restoration Goals and Objectives Related to Wetlands:

Erosion and sedimentation control;
Riparian enhancement, and
Habitat restoration.

List of Major Restoration Activities:

Restoration activities involve the planning for the removal of dams, erosion / sedimentation control, the restoration of southern steelhead trout, riparian enhancement, stream bank protection, water quality management, and wetland restoration.

As part of the dam removal planning, consideration will be given to providing access and day-use recreational facilities, extension of the coast-to-mountain bicycle trail, outdoor educational facilities, and acquisition of non-federal in holdings in the Los Padres National Forest.

The Bureau of Reclamation has initiated an appraisal study to be completed in the spring of 2000. Congress allocated $100,000 to study the dam’s removal. A demonstration project to commence decommissioning of the dam occurred in the fall of 2000, before the Secretary Babbitt left office.