| dc.description.abstract | California’s mountainous topography, exposure to occasional heavily moisture-laden
storm systems, and varied communities and infrastructures in low lying areas make it highly
vulnerable to floods. An important question facing the state—in terms of protecting the public
and formulating water management responses to climate change—is “how might future climate
changes affect flood characteristics in California?” To help address this, we simulate floods on
the western slopes of the Sierra Nevada Mountains, the state’s primary catchment, based on
downscaled daily precipitation and temperature projections from three General Circulation
Models (GCMs). These climate projections are fed into the Variable Infiltration Capacity (VIC)
hydrologic model, and the VIC-simulated streamflows and hydrologic conditions, from
historical and from projected climate change runs, allow us to evaluate possible changes in
annual maximum 3-day flood magnitudes and frequencies of floods. By the end of the 21st
Century, all projections yield larger-than-historical floods, for both the Northern Sierra Nevada
(NSN) and for the Southern Sierra Nevada (SSN). The increases in flood magnitude are
statistically significant (at p<=0.01) for all the three GCMs in the period 2051–2099. The
frequency of flood events above selected historical thresholds also increases under projections
from CNRM CM3 and NCAR PCM1 climate models, while under the third scenario, GFDL
CM2.1, frequencies remain constant or decline slightly, owing to an overall drying trend. | |
