Hydromorphic Response of Groundwater and Surface Water Systems
Engineering Hall 2430 - Colloquia Room
Environmental Engineering Seminar
Dr. Brian Thomas
University of California, Irvine
The objective of this research is to illustrate how human impacts including urban storm water regulation and groundwater withdrawals have altered groundwater and surface water interaction. First, the behavior of groundwater elevations in Boston is investigated to address the impact of storm water recharge best management practices. Results illustrate that recharge practices in Boston have resulted in a very small yet statistically significant increase in groundwater elevations in Back Bay. Further, hybrid multivariate regression model developed for the study are used to illustrate future storm water planning scenarios. Secondly, I explore the effect of human withdrawals in the characterization of groundwater-surface water (gw-sw) behaviors using baseflow recession analysis. Linear behaviors are assumed to illustrate the effect of including human withdrawals in estimation of baseflow parameters, which for the linear assumption is termed the baseflow recession constant. The performance of traditional estimators is compared to newly derived estimators; the results suggest that traditional semi-log estimation approaches adapted to include withdrawal terms are preferred. Further, analysis of variance methods are developed to identify factors which give rise to variability in estimates of the baseflow recession constant. Among the factors considered, both drainage density and human withdrawals were found to have significant and similar explanatory power for the baseflow recession constant. Thus, results document the importance of incorporating human withdrawals into models of the baseflow response of a watershed.