Quantification of Variabilities of Baseflow of Watersheds

Abstract

The U.S. Geological Survey National Water-Quality Assessment Project conducted a study of 225 sites in the Chesapeake Bay watershed to estimate base flow. Baseflow is the estimated volumetric discharge of water, primarily from groundwater sources, that is relayed to the measurement sites. The study is necessary in order to address the nation’s water supply for changes in the environment. Baseflow is estimated using a recursive digital filter. Calculating the variability of baseflow water discharge is important to make informed decisions about water regulation. We explored the estimation of variability of baseflow using two methods: the bootstrap method and the Delta method. Each method has its own limitations and requirements. Ultimately, bootstrapping was shown to be a reasonable recommendation for estimating baseflow variability. The bootstrapping algorithm was parallelized in order to compute numerous iterations on multiple processors for big data analysis. The derivation of the variability of a non-constant streamflow was also considered for further study, but not implemented.