Policies in line to handle climate change
April 4, 2008
Policies to reduce the amount of fine sediments and nutrients entering Lake Tahoe are on the right track to handle climate change, according to a Tahoe Environmental Research Center scientist who recently released a new study on global warming and Lake Tahoe.
A study about climate change and how it could affect water circulation in the lake and change the conditions for fish and plants was presented by TERC Director Geoffrey Schladow at a conference March 18.
Since, he has had many agencies around the basin make inquiries.
“I think agencies were concerned about what does this mean,” Schladow said. “It’s fortunate that a lot of the effort by a lot of the agencies in both states and the federal government seem to be on the right track.”
The study combined 40 years of weather data in the basin with mathematical models of climate change to create scenarios of future lake conditions. The team then took those scenarios and used a lake physics model to see how combinations of air temperatures, cloudiness and wind speed would affect the mixing of water layers.
Currently the lake mixes on average every four years with the deepest mixing in February. Mixing circulates oxygen through the lake and supports aquatic life. It also brings nutrients up from the bottom of the lake which could support algae growth.
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The study showed that lake mixing could become less frequent and deep and could stop by 2019.
Less water mixing would mean less oxygen to deeper parts of the lake, which could affect the creatures that live on the bottom of the lake. There is also a worry that if oxygen is gone, the phosphorous that is locked up on the lake floor could be released to the surface and fuel algae growth.
But Schladow said many of the policies around the lake, including the lake’s regional plan and the Total Maximum Daily Load goals are on track to help mitigate these changes.
“We think the negative affect of climate change could be best reduced or mitigated by the same nutrient reduction strategy embodied in the TMDL,” Schladow said.
Schladow’s team has been studying climate change and the lake for the past four months, and plans to extend the study and release a paper by August describing the work done.
He is also looking into funding for a study on how climate change affects water quality. That study would look more specifically at climate change, nutrients and clarity.
Knowing this information is helpful in developing policies, Schladow said.
“It’s a great advantage,” Schladow said. “It would be a shame to spend millions designing a system that couldn’t cope with the changed hydrology.”
The new regional plan is able to adapt to scientific findings with significant support, said Tahoe Regional Planning Agency spokesman Dennis Oliver.
“Researchers need to continue analyzing and monitoring global warming and lake mixing to verify what they think they see,” Oliver said. “Nutrient loading has been a big issue all along and we’ve been concerned about that.”