Stormwater Monitoring Following Caldor Fire Was Positive, But More Monitoring Needed | South Lake Tahoe


LAKE TAHOE, CA / Nev. – On October 24, during the atmospheric river-driven storm, League to Save Lake Tahoe staff and Pipe Keepers citizen science volunteers collected stormwater samples, performed qualitative visual observations, and took quantitative measurements indicators of water quality, including turbidity. Participants monitored stormwater at 25 sites, including 16 storm drains and 8 stream sites on Tahoe’s south shore that drain areas burned by the Caldor fire.

Their work provided a snapshot of conditions at selected sampling sites at one point in time, and therefore does not tell a full story of how the storm of October 24, or any weather event since the Caldor fire, has had an impact on the quality or clarity of Lake Tahoe’s water. Stormwater monitoring must continue – by agencies, research institutes and citizen scientists – and the results must be compared and synthesized over time to gain a conclusive understanding of the short and long term impacts on the lake. Tahoe that may occur due to the Caldor fire. . Pipe Keepers will continue to monitor monthly flows at 10 sites until at least June 2022, with additional monitoring to take place as determined during the course of the project.

The first readings of the Pipe Keepers’ work were surprisingly positive (i.e. low turbidity readings) given the intensity of the storm and precipitation over the recently burned areas, but these readings are only a set of measurements and data, not conclusions. Turbidity and nutrient concentrations, as well as the volume and duration of stream flows, determine the amount of sediment, ash, and nutrients carried into Lake Tahoe.

Data collection by Citizen Scientists and League staff follows standard methods and protocols, including quality assurance and control, to ensure validity, accuracy, and comparability with other monitoring efforts. Pipe Keepers’ citizen science data collection complements the professional and robust monitoring of water quality and stream flow that takes place under the Lake Tahoe Interagency Monitoring Program (LTIMP), which uses automatic sampling devices and stream flow gauges at fixed locations around the Tahoe Basin. The US Geological Survey and the UC Davis Tahoe Environmental Research Center are very important contributors to the program, along with many others.

The Tahoe Science Advisory Board recently approved an expansion of the LTIMP program in light of the high likelihood that winter precipitation could displace soils and ash from the slopes burned during the Caldor fire and into the lake. The League has advocated for the expansion of LTIMP, knowing that the data it produces would be crucial to understanding how wildfires can create delayed consequences for Lake Tahoe.

Pipe Keepers’ citizen science data contribution complements LTIMP, in particular by providing visual observations and qualitative data that is not otherwise captured, including photographs and descriptive reports of the environment surrounding the sites of sampling. It also adds other measurements of nutrient loadings and turbidity, which are determined by laboratory analysis. Citizen scientists have the option of visiting different sites as needed, where autosamplers and flow meters are attached. Finally, citizen science engages the community directly in environmental science, which builds an ethic of environmental stewardship.

Collaboration between scientists, public agencies, research institutes, non-profit organizations and community members will help to better understand the environmental impacts of forest fires, identify priority areas to be addressed and help implement solutions to protect, preserve and conserve Tahoe Blue.

The impacts of the Caldor fire on Lake Tahoe are not yet fully understood. Thanks to the work of scientific agencies, research institutes, governments and citizen scientists, the impacts will be discovered in time.


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