Lake Tahoe is an Outstanding National Resource Water and is world renowned for its exceptional clarity. Unfortunately, the clarity of Lake Tahoe is declining at an alarming rate of over one foot each year. The loss of clarity is due largely to soil erosion and surface runoff associated with the development of urban areas in the Tahoe Basin.

Participants in the Lake Tahoe Basin restoration effort are aggressively trying to reduce the amount of non-point sources of nutrients and sediments entering the Lake using management measures called BMPs, or Best Management Practices. This program is important because controlling non-point source sediment and nutrient pollution is the best way to keep Lake Tahoe reverse the trend of clarity loss.

The framework for these innovative watershed management measures comes from a variety of water quality protection laws, outlined in the Regional Plan for the Lake Tahoe Basin, the Water Quality Management Plan for the Lake Tahoe Basin (208 Plan) and the Federal Clean Water Act (CWA) of 1972.

What is a Lake Tahoe Best Management Practice?

At Lake Tahoe, Best Management Practices (BMPs) are defined as "structural and nonstructural practices proven effective in soil erosion control and management of surface runoff in the Lake Tahoe Region." Eroding soils and surface water runoff transport pollutants, sediment, and nutrients to the Region's rivers and streams, which lead to Lake Tahoe. Pursuant to subsection 25.5.A of the TRPA Code of Ordinances, all property owners in the Tahoe Basin are required to install infiltration facilities designed to accommodate the volume of runoff from a six-hour storm with a two-year recurrence probability (or a twenty year/one hour storm, which is approximately one inch of precipitation in an hour). These infiltration facilities are BMPs.

Best Management Practices vary from site-to-site, and include temporary best management practices and permanent best management practices. Temporary BMPs are utilized to keep sediment on-site when an area is disturbed by construction. Permanent BMPs are utilized to minimize erosion on residential, commercial, and public service properties when they aren't disturbed by active construction.

Sometimes BMPs are relatively simple, such as revegetating a bare slope behind a home, and sometimes they are more complex, such as a storm water pre-treatment system for a large parking area. However, whether simple or complex, BMPs are site-specific. Adequate BMP requirements and correct installation can be accurately determined with a site evaluation by a professional with your local Resource Conservation District (RCD) or the Tahoe Regional Planning Agency (TRPA).

In order for a BMP to be effective, it must be maintained and monitored.Click here to learn more.

Why are Best Management Practices important?

Lake Tahoe is losing its crystal water clarity at the alarming rate of more than a foot a year. At the current rate of decline, it is estimated that Lake Tahoe will lose its blue brilliance in just ten years.  Non-point source (NPS) pollution, or pollution originating from many diffuse sources is contributing to the decline in Lake Tahoe's water clarity. NPS pollution is caused when rain or snowmelt causes overland flow that transports various pollutants from the ground's surface directly into the surface waters that lead to Lake Tahoe.

Research has found that the addition of sediment and nutrients such as nitrogen and phosphorus from non-point source pollution to Lake Tahoe promotes algal blooms that result in a further loss of water clarity. The best way to prevent this is to slow and store runoff using BMPs.

Who Needs To Implement Best Management Practices?

All property owners in the Lake Tahoe basin need to implement BMPs, whether they own residential or commercial properties. Public service property managers are also required to implement BMPs, however, public lands may be on a slightly different implementation schedule.

All the watersheds in the Tahoe Basin were prioritized for BMP implementation depending on various factors including soil erodibility, steepness of terrain, ratio of development to undisturbed land, and relative inputs of nutrients and sediment from the watershed. Utilizing this data, the watersheds were determined to be Priority One, Two or Three.

Property owners in Priority One watersheds are required under Section 25 of the TRPA Code of Ordinances to implement BMPs on their property by October 15, 2000. Click here for a summary of the public notifications made for Best Management Practice Retrofit Requirements in the Lake Tahoe Basin.

Subsequent target dates for full implementation of BMPs are October 15, 2006 for property owners in Priority Two watersheds, and October 15, 2008 for property owners in Priority Three watersheds. Click here to refer to the map to locate the priority watershed where your property is located.