Lake Tahoe Info tracks monitoring programs throughout the Tahoe Region. Featured monitoring programs have detailed monitoring data, maps, and photos available in the system. Other Monitoring Programs are tracked with useful information such as partnering agencies, related indicators, and documents.
Click a featured monitoring program to see program details and access monitoring data for individual monitored sites.
TRPA and local partners monitor bicycle and pedestrian activity throughout the Region to understand high use areas, mode-split, and support grant applications and reporting. Count information also informs policies and programs targeted to improve and support active transportation.
TRPA monitors background noise levels in all Area Plans in the Tahoe Basin to ensure noise levels are not disturbing people and wildlife, and to maintain the unique characteristics of the Basin. Each Area Plan has its own allowable noise level in TRPA's thresholds, with maximum average 24-hour allowable noise levels ranging from 45 decibles (dB) in wilderness areas to 65 dB in industrial areas.
TRPA regularly monitors noise along highway corridors in the Lake Tahoe Basin to ensure noise limits are not being exceeded. Because noise from highways is the largest source of background noise in the Basin, noise limits near highways ensures the serenity of the Tahoe Basin is maintained.
TRPA regularly monitors noise from motorized watercraft in the shorezone of Lake Tahoe to ensure noise levels are not being exceeded. Shorezone noise limits are in place to maintain the serenity of Lake Tahoe and to protect sensitive wildlife.
The Tahoe Resource Conservation District (Tahoe RCD) is leading the effort to measure pollutants in urban runoff at Lake Tahoe to help evaluate the combined effectiveness of pollutant control measures and consistently track and report monitoring findings. This effort, known as the Regional Storm Water Monitoring Program (RSWMP) is a collaborative program supported by regulatory agencies, local government representatives, and scientists in the Lake Tahoe region.
The RSWMP Data Management System (DMS) was created for Tahoe RCD by the Desert Research Institute (DRI) and Geosyntec. The DMS retrieves and analyzes stormwater monitoring data to evaluate effectiveness of regional stormwater management strategies. That monitoring data is automatically retrieved from the DMS and displayed in LT Info. This page can be used to explore and understand the RSWMP monitoring program and select monitoring data.
Funding for RSWMP implementation, DMS development, and display on LT Info was provided by the California State Water Resources Control Board.
TRPA began monitoring perennial streams in 2009 to determine if TRPA thresholds for stream habitat are being met, and to detect changes in the overall condition of the Tahoe Basin's streams. Bioassessment, which uses benthic macroinvertebrates (BMI) and physical stream habitat to assess overall stream health, is used to monitor the Basin's streams. To obtain a stream health "score", the California Stream Condition Index (CSCI) is used. The CSCI is a model that compares the BMI found in sampled streams against the BMI expected to be found in pristine streams in the Sierra Nevada.
Tahoe Yellow Cress (TYC, Rorippa subumbellata) is a small native plant that grows on the shoreline of Lake Tahoe and no where else in the world. It lives only on the sandy beaches and dunes at the ever-changing margin of the lake. Impacts from recreation and development first led to conservation concerns in the 1970’s and TYC has been listed as endangered in both states since 1982. In 1999, a multi-agency and private interest group task force was formed to develop and implement a conservation strategy to promote the recovery and conservation of TYC. The conservation strategy provides an adaptive management framework and options for avoiding, minimizing, and mitigating impacts to TYC and its habitat on public and private lands. The TYC Stewardship Program recognizes the critical role of private landowners in ensuring the long-term survival of TYC.
A similar species can be found growing alongside TYC on the shores of Lake Tahoe. TYC has plump round fruits, fleshy leaves, and a compact growth form, while western cress (Rorippa curvisiliqua) is often taller, the fruits are elongated and narrow, and the leaves are less fleshy and turn purple with age. In contrast to the rarity of TYC, western cress is very widespread throughout the western U.S.
In partnership with the state DOTs, TRPA collects, monitors, and analyzes roadway traffic volume data from several dozen count stations throughout the Tahoe region.
TRPA conducts on-going monitoring to inform transportation policy and programs with the goal of providing a successful multi-modal transportation system that appeals to users, supports mobility needs, and decreases dependency on the private automobile. TRPA has been monitoring transportation performance since the early 1970s including traffic counts, travel mode choice, and demographic and air quality trends so that planners can evaluate the Lake Tahoe Region’s transportation system and use best available science to inform policy-making. The 2016 FAST Act requires states and MPOs to develop targets for specific performance measures related to safety, transit, and roadway/bridge conditions. To comply with FAST Act regulations, TRPA has prioritized identifying performance measures and setting targets for transit to help transit agencies improve the efficiency and effectiveness of the level of service they provide in Tahoe.
Lake clarity measurements have been taken continuously by UC Davis Tahoe Environmental Research Center (TERC) since 1968, when a white disk, called the Secchi disk, could be seen down to 102.4 feet. It is one of the longest, unbroken clarity records in the world. Secchi depth is the most widely used method of clarity measurement, and the values are consistent with laser-based measurements also taken by TERC researchers. Water transparency in Lake Tahoe is largely controlled by particles blocking light penetration either by scattering or by absorption. The decline in transparency is likely a result of additions of fine sediment particles and growth of phytoplankton (algae) mainly from stormwater runoff, stream erosion, atmospheric deposition, and changes to lake mixing.
Lake Tahoe Info tracks many other monitoring programs. Click the Other Monitoring Programs link to see the full suite of monitoring activities in the basin. These other monitoring programs are no less important than the featured programs above, but LT Info has not yet integrated an inventory of individual monitoring sites or the actual observed data for these other pgorams.