Water, Adaptive Management
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Lake Tahoe was losing its famed clarity quickly and there was a significant threat to a $3 billion dollar per year economy. Millions of dollars were being invested to fix the problem but there was little evidence to show the benefits of these investments, target funding toward the most treatable sources, or understand how much treatment was needed to return the lake to its previous beauty.
To address this issue, the Lahontan Regional Water Quality Control Board (Lahontan) and Nevada Division of Environmental Protection (NDEP) collaborated to develop the Lake Tahoe TMDL. The Lake Tahoe TMDL is a science-based plan to better understand the causes of the loss in lake clarity, determine how much pollution needs to be reduced to reinstate historic clarity, and develop a workable, cost-effective implementation strategy.
Environmental Incentives worked closely with Lahontan and NDEP, and in partnership with Northwest Hydraulic Consultants, 2NDNATURE, and Sitka Technology Group to design, test and launch the Lake Tahoe TMDL Management System. Environmental Incentives provided the primary linkage between policy makers and technical investigators to ensure that TMDL Integrated Water Quality Management Strategy (IWQMS) analyses were policy relevant and cost effective. These investigations involved evaluations of pollutant load reductions at typical sites, as well as extrapolations to estimate basin-wide potential load reductions. We also assisted with the identification and analysis of load allocation options.
As part of this effort, we produced one of the first reasonable assurance analyses for TMDL implementation, the Lake Tahoe TMDL Pollutant Reduction Opportunity Report, through management of five technical teams and technical editing of the draft product. This report provided a first estimate of the potential basin-wide pollutant load reductions at several levels of effort, and has proved to be a critical tool in developing TMDL implementation strategies.
This first of its kind TMDL implementation plan led to development of the Lake Clarity Crediting Program – a sediment and nutrient reduction accounting system for urban areas that gets permittees credit for effective actions. During the first 5-year permit cycle, permittees in California and Nevada exceeded the sediment load reduction target of 10%. This program has also created unusually positive relationships by aligning the incentives of regulators and permittees, and has replaced stringent effluent concentration limits with load reduction credits in their permit. Permittees have supported a 21% load reduction target in their next permit.
The Water Board is grateful for the strong partnerships in the Lake Tahoe basin. Working together, we’ve successfully reduced fine sediment reaching the lake by more than 10% and have gained unprecedented support of our new permit, with its redoubled target of 21% load reduction.”
Robert Larsen, Lahontan Water Board