Modeling transport of nutrients & sediment loads into Lake Tahoe under climate change

Climatic Change
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Abstract

The outputs from two General Circulation Models (GCMs) with two emissions scenarios were downscaled and bias-corrected to develop regional climate change projections for the Tahoe Basin. For one model—the Geophysical Fluid Dynamics Laboratory or GFDL model—the daily model results were used to drive a distributed hydrologic model. The watershed model used an energy balance approach for computing evapotranspiration and snowpack dynamics so that the processes remain a function of the climate change projections. For this study, all other aspects of the model (i.e. land use distribution, routing configuration, and parameterization) were held constant to isolate impacts of climate change projections. The results indicate that (1) precipitation falling as rain rather than snow will increase, starting at the current mean snowline, and moving towards higher elevations over time; (2) annual accumulated snowpack will be reduced; (3) snowpack accumulation will start later; and (4) snowmelt will start earlier in the year. Certain changes were masked (or counter-balanced) when summarized as basin-wide averages; however, spatial evaluation added notable resolution. While rainfall runoff increased at higher elevations, a drop in total precipitation volume decreased runoff and fine sediment load from the lower elevation meadow areas and also decreased baseflow and nitrogen loads basin-wide. This finding also highlights the important role that the meadow areas could play as high-flow buffers under climatic change. Because the watershed model accounts for elevation change and variable meteorological patterns, it provided a robust platform for evaluating the impacts of projected climate change on hydrology and water quality.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Modeling transport of nutrients & sediment loads into Lake Tahoe under climate change
Series title Climatic Change
DOI 10.1007/s10584-012-0629-8
Volume 116
Issue 1
Year Published 2013
Language English
Publisher Springer
Contributing office(s) Branch of Regional Research-Western Region
Description 16 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Climatic Change
First page 35
Last page 50
Country United States
State Nevada;California
Other Geospatial Lake Tahoe
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