BMPs: What is the Problem?

Lake Tahoe’s Clarity Decline

Current trends show that Lake Tahoe’s clarity has stabilized after declining at an alarming rate of over one foot per year since measurements began in 1968. The Lake Tahoe Total Maximum Daily Load has shown that fine sediment and nutrients in stormwater runoff coming from developed areas in the Lake Tahoe Region causes most of the lake’s clarity loss. Implementing Best Management Practices will play a major role in continuing to stabilize and ultimately restore Lake Tahoe’s water clarity. Thousands of properties are in compliance, have you done your BMPs?


What is Stormwater Runoff?

In an undisturbed watershed, the majority of stormwater is captured by vegetation, and absorbed and filtered through the soil. Development, such as roads, driveways and rooftops, alter the watershed by creating impervious surfaces that prevent stormwater from infiltrating. Instead, stormwater runs over the surface, collecting pollutants such as sediment, nutrients and oil and grease as it travels, enters the nearest stormdrain or stream and ultimately ends up in Lake Tahoe. Many people mistakenly think that storm drains lead to a sanitary sewer system, where the stormwater runoff is treated. While this is true in some communities, this is not true at Lake Tahoe! All storm drains eventually lead to Lake Tahoe. Runoff containing fine sediment and nutrients cloud the water and feed algal growth, which have led to over 30 feet of clarity loss since the 1960’s.