State Water Resources Research Institute Program
Project ID: 2011NV180B
Title: Effects of Regional Climate Change on Snowpack in Northern Nevada: Research and Education
Project Type: Research
Start Date: 3/ 1/2011
End Date: 2/28/2013
Congressional District: NV02
Focus Categories: Climatological Processes, Hydrology, Water Supply
Keywords: Nevada, Climate Change, Snow Water Equivalent
Principal Investigators: Schumer, Rina; Makowski Knust, Anna
Federal Funds: $ 26,962
Non-Federal Matching Funds: $ 57,664
Abstract: The Bureau of Reclamation (BOR) currently uses a decision support system (DSS) to manage the Truckee River water system and adhere to the operating agreement in place for the River. Application of the DSS requires a coordinated effort among researchers, operational product designers, and water managers. For example, the Truckee River Riverware operations model is driven by a daily streamflow time series. Currently, a representative time series is selected based on volumetric forecasts from a variety of sources. The Natural Resource Conservation Service (NRCS) uses a model that employs empirical relationships between historical observations of precipitation and streamflow, and also considers the results of physically based precipitation-runoff models developed by the National Weather Service and the Desert Research Institute.
These precipitation-runoff models can also be used to evaluate the impact of climate variations on streamflow in the Truckee River watershed. Water resource managers are increasingly required to incorporate information related to climate in their decisions. Like many watersheds in the Sierra Nevada, it is likely that the first sign of global warming in the Truckee River watershed will be an earlier start to the spring runoff (Dettinger, et al., 2004), requiring a modification of reservoir operation on the river. The resultant reduction in streamflow in the late summer directly affects Truckee River water quality issues, as dissolved constituent concentrations increase dramatically under low flow conditions. The Truckee River Operating Agreement Joint Environmental Impact Statement/Environmental Impact Report identified water quality of the Truckee River as a key concern for flow management. As a result, management practices in the basin may require modification based on predicted flows.
Snowmelt accounts for the majority of the annual streamflow in the Sierra Nevada and other mountainous regions. Physically-based precipitation-runoff models in these areas estimate streamflow by deterministic representation of the accumulation and depletion of snowpack. Physical processes, such as sublimation, evaporation, infiltration, and subsurface flow, are combined with an energy balance and a water balance, resulting in streamflow estimates.