The Impact of Accurate Parameterization of Snow Storage in Operational Hydrology Models

A. C. Burnop
Venkataramana Sridhar, Boise State University
J. P. McNamara
A. N. Flores

Abstract

Ensuring that model inputs and parameters are correct and accurate is one of the largest challenges with hydrologic modeling, especially in regions with complex topography where snow is the predominant source of available water for the year. In these regions, meltwater does not necessarily enter a catchment where snow falls, but where it melts. Significant redistribution and differential melt can cause highly heterogeneous water inputs. Proper parameterization of end-of-season snow storage is essential. Aerial depletion curves relating changes in snow water equivalent to changes in snow covered area are commonly used to parameterize the impact of heterogeneous snow storage. However, little guidance exists to define the shape of depletion curves. In this research we evaluate the impact of the level of detail in aerial depletion curves on the performance of the National Weather Service’s operational hydrologic model, the Sacramento Soil Moisture Accounting Model (SAC-SMA) coupled with the SNOW-17 model. We apply curves developed from detailed field measurements and remote sensing to determine the level of detail required to accurately simulate streamflow and soil moisture in the Dry Creek Experimental Watershed located just north of Boise, Idaho.