Estimating Snowmelt Infiltration by Numerical Integration of Soil Moisture Data

ABSTRACT Predicting snowmelt infiltration into soils is critical for water supply management, which has prompted a call for additional research on infiltration beneath snowpack. This study estimates snowmelt infiltration, through a first‐order diagnostic process, using soil moisture data available, for example, through snowpack telemetry (SNOTEL) in the USA, and the global High Resolution Daily Multilayer Soil Moisture Dataset. Given soil moisture versus time at various depths, depth‐integrated moisture content provides total water volume versus time. Snowmelt infiltration is estimated based on the assumption that increases in total water volume result from infiltration at the soil surface. This study details the codes written for numerical integration of soil moisture data, then documents model verification using infiltration data simulated by HYDRUS‐1D, model validation using infiltration measured in a field study, and model application with three North American case studies across a range of elevations. For these case studies, an estimated 12%–36% of snow water equivalent (SWE) infiltrated to soil moisture. Codes and data are available through the online repository HydroShare.