Volunteers continue to measure Caldor Fire impact on Tahoe

Last month, during the storm driven by an atmospheric river, the League to Save Lake Tahoe’s staff and Pipe Keepers citizen scientist volunteers collected stormwater samples, made qualitative visual observations, and took quantitative measurements of water quality indicators, including turbidity.

Participants monitored stormwater at 25 sites, including 16 stormwater pipes and eight stream sites on Tahoe’s south shore that drain areas burned by the Caldor Fire. While readings from the Pipe Keepers’ work represent one set of measurements and are not conclusions, officials were surprised to find lower-than-expected turbidity given the intensity of the storm and precipitation on recently burned areas.

Work done last month provided a snapshot of conditions at select sampling sites at a single moment in time, according to a news release from the League to Save Lake Tahoe, and therefore does not tell a complete story of how the Oct. 24 storm, or any weather event since the Caldor Fire, has impacted the water quality or clarity of Lake Tahoe.

Stormwater monitoring must continue by agencies, research institutions 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 Lake Tahoe that may be occurring due to the Caldor Fire. The Pipe Keepers will continue monthly stream monitoring at 10 sites through at least June of 2022, with additional monitoring taking place as determined over the course of the project.

Data collection by the league’s citizen scientists and staff follows standard methods and protocols, including quality assurance and quality control, to ensure validity, accuracy and the ability to compare with other monitoring efforts. The Pipe Keepers citizen science data collection complements the water quality and stream flow monitoring that takes place through the Lake Tahoe Interagency Monitoring Program, which uses autosampler devices and stream flow gauges at fixed locations around the Tahoe Basin. The US Geological Survey and University of California, Davis Tahoe Environmental Research Center also contribute to the program, along with many others.

The Tahoe Science Advisory Council recently approved an expansion of the monitoring program in light of the high probability that winter precipitation could move soils and ash off of slopes burned during the Caldor Fire and into Lake Tahoe. The League to Save Lake Tahoe advocated for the expansion of the program, knowing data it produces may be crucial to understanding how wildfire can create delayed aftereffects for Lake Tahoe.

The contribution of Pipe Keepers provides visual observations and qualitative data that is not otherwise captured, including photographs…