The preservation and restoration of watersheds and stream environment zones (SEZs) are important components of the Conservancy's efforts to preserve and enhance the natural environment of the Lake Tahoe Basin.

A SEZ consists of a stream and its drainage, as well as marshes and meadows. Their preservation and restoration is essential to the health of the lake, because they provide natural treatment and conveyance of runoff, which they can reduce by as much as 70% to 90%.

SEZs also provide many other benefits. While they comprise only 5% of the land area within the Tahoe Basin, they are key habitat for wildlife, enhance the scenic values of the basin, and provide dispersed recreation opportunities for hikers.

Disturbance and urban encroachment seriously reduce the ability of an SEZ to carry runoff and filter out sediments and nutrients, however. And of the 17,700 acres of SEZ lands that originally existed on the California side of the basin, 4,400 have been disturbed, developed, or subdivided. Because these lands are so important, there is an urgent need to preserve and to restore as much of these lands as possible.

This program involves a number of direct and grant-funded activities including the removal of fill and improvements such as dams, the revegetation of slopes, and the restoration of stream channels.

The restoration of SEZ's and streams is a relatively new and complex field. Consequently, the Conservancy has, with its grantees, sought to include innovative techniques in its projects. For example, the Conservancy, in partnership with the City of South Lake Tahoe, the Tahoe Resource Conservation District, and the U.S. National Resources Conservation Services, restored a portion of Cold Creek by constructing a 6,000 foot meandering channel. A number of innovative methods were used such as protecting the restored channel with tree root-wads and sod and willow transplants and installing rock vortex weirs to help control stream flow.

Through this project, the Conservancy learned that successful stream restoration requires first determining the natural, stable form of a channel, which involves calculating the original slope, depth, width, and many other factors. Construction techniques should then emphasize the use of natural vegetation and materials, such as root wads and willow transplants, rather than rock and concrete. During construction, tracked equipment should be used, and metal landing mats put down, to minimize impacts on meadows and other fragile areas that are being worked on.

In the Griff Creek project, funded by a Conservancy grant to the North Tahoe Public Utility District, and the Lonely Gulch Creek project, undertaken by the Tahoe City Public Utility District with the aid of a Conservancy grant, rock-step pools were installed to restore the natural condition of the stream. Biodegradable erosion control blankets were used to protect newly constructed stream banks, along with cuttings of willow and other native plants.

To date, the Conservancy has authorized the expenditure of more than $6.1 million for ten SEZ and watershed projects and ongoing restoration of Conservancy lands, which involve the preservation and restoration of 35 acres of land and 1.2 miles of stream.

In addition to the projects mentioned above, the Conservancy has funded the Wolf Street, Kingswood West and Burton Creek projects in North Tahoe and the Meyers project in South Lake Tahoe. It has made possible, through grants, the City of South Lake Tahoe's Ski Run Boulevard project, El Dorado County's Arapahoe and Southern Pines projects, and Placer County's Tahoe City Water Quality Improvement Project.

Planning and design are being completed on the Carnelian Canyon and Snow Creek projects in North Tahoe, and restoration work is expected to begin in 1998.

The Upper Truckee River is in the planning and design stage and awaits funding. It is the largest project in the Conservancy's SEZ program, involving more than 200 acres of land.

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