Relevance

There are 63 tributaries that drain into Lake Tahoe, and one tributary that drains from the basin. The amount of water flowing through a stream is primarily dependent on the size of its watershed and the amount of precipitation within a given year. Streams provide critical habitat to a diversity of native and non-native fish populations and other riverine-dependent organisms. Historic logging, grazing, and land use interrupted the hydrologic integrity of many of the streams and tributaries draining into Lake Tahoe, and the results of these legacy activities are evident today. Alteration of stream flow regimes, such as water diversions, can result in adverse impacts to stream habitat diversity, function, and productivity of aquatic ecosystems and organisms. A component of the TRPA Regional Plan is to maintain a healthy functioning fishery through the conservation and restoration of natural flow regimes.

Human and Environmental Drivers

Weather, climate patterns, geology, elevation, and topography all significantly affect stream flow characteristics. Historic channel modifications associated with logging activities and land use (e.g., dams, water extraction, and within-watershed diversions, urban development and infrastructure, flumes, stream channelization, and flood control impoundments) that preceded the 1987 Regional Plan altered stream channel structure and watershed-specific hydrology.

No related projects or programs defined for this indicator.

Management Status Rationale

Implemented. Permits were reviewed to determine if any stream diversions were permitted and no new diversions were allowed. No permits have been issued that permitted new diversions.