Lake Tahoe is one of the largest alpine lakes in the world, known internationally for it's remarkable clarity. Its blue waters, though, are threatened by man's disturbance of the surrounding and sensitive lands. Their erosion not only disfigures the beauty of the area but clogs streams with sediment and enlarges deltas into Lake Tahoe. Accompanying the eroded particles on their journey to the Lake are nutrients such as nitrogen and phosphorus that promote the growth of algae. As algal populations flourish, the lake clarity diminishes.

Sediment and nutrient input have been a problem in the Tahoe Basin since it began to see land development in the late 1800's. Back then, grazing and logging were the major contributors to soil loss from this fragile environment. Fire has also taken a toll on the land. Today, sources of erosion include roads, building construction, off-highway vehicle routes, ski areas and grazing allotments. Fertilizers used indiscriminately on golf courses (usually found adjacent to riparian areas), ski areas and lawns add to the nutrient load reaching Lake Tahoe.

The USDA Forest Service is not immune to most of these disturbances because it manages lands that either encompass or are adjacent to these highly-developed and heavily-used areas. The lands managed by the Forest Service in the Tahoe Basin (75% of the land area in the Basin) come under the jurisdiction of several regional, state (California and Nevada) and local agencies, most of which have a strong emphasis on water quality. Thus the erosion problems encountered by the Forest Service in the Tahoe Basin are numerous and varied. Their solution can involve regulatory complexities that border on Draconian nightmares.

With an annual budget averaging $500,000, some of which has come from the Santini-Burton Act of 1980, the Lake Tahoe Basin Management Unit has taken the lead in Tahoe in restoring over 3000 acres of disturbed land that has threatened water quality in the Tahoe Basin. Projects in the last decade have included the following:

Former Jenning's Casino Site - Following acquisition of this parcel, the Forest Service removed the foundations of a partially-constructed casino and rehabilitated the disturbed area. The disturbed area was reshaped to its approximate original contours and revegetated with grasses and shrubs. Burke Creek, which had been diverted to a straight road side ditch, was rerouted through a meandering rock-lined channel that is now thickly vegetated with willows. The Creek was directed into and out of the excavated site to make a sedimentation pond which now attracts geese, ducks and other riparian-dependent birds. The project not only restored a drastically disturbed riparian area but assured continued health of a meadow downstream. Water quality monitoring results show that Burke Creek, which drains a residential and industrially developed watershed, drops a significant amount of sediment in the pond. In addition, the meadow filters out additional sediment as well as significant amounts of nutrients.

Santa Fe Road - Downstream of a golf course, housing development and major highway was an area originally slated for homes. A road was paved through the area and named "Santa Fe". The area reverted to multi-agency ownership including ElDorado County, the USFS and the State of California. Forest Service monitoring of the small creek running through the area showed high concentrations of nutrients and sediments. Together with the County, the Forest Service closed the Santa Fe Road in 1988, removed the asphalt, and revegetated the newly-expose soil. A rock rubble barrier was placed in the creek to partially divert it into the adjacent meadow. This lessens the energy of the creek during high flows and encourage sediment deposition. Since nutrients such as nitrogen and phosphorus adsorb to sediment particles, an added benefit is their deposition as well uptake by the meadow vegetation. Continued monitoring of the creek should indicate the effects to water quality of this project.

Blackwood Canyon - For 100 years this watershed was overgrazed and heavily logged. In the 1950's and 1960's an extensive floodplain for Blackwood Creek was mined for gravel. By the 1960's, following a few intense rain-on-snow events, the channel had downcut and straightened resulting in an enlarged delta at the mouth of Blackwood Creek. Since the late 1970's close to a million dollars have been spent stabilizing the watershed.

Projects include paving three miles of heavily-used road, installing gates for seasonal road closures, constructing gully plugs and check dams, and rock lining small tributary channels. A diversion structure was built in 1979 above the mining site to reroute Blackwood Creek into its original and more meandering channel. The ponds now serve to attenuate flow energy, allowing for sediment deposition. The former quarry operation site, paved and compacted by years of use, was first ripped to remove the thick layer of gravel and base rock then ripped again to break up the compacted soil beneath. Topsoil was brought in, mixed with the mineral soil, seeded, fertilized and mulched.

The fisheries in Blackwood Creek had suffered from the loss of habitat following the degradation of its channel. Projects to enhance habitat include boulder placements in the main channel as well as combination boulder-log structures keyed into the channel banks. Their success has already been apparent in the numbers of spawning rainbow trout attracted to these structures.