This research conducted a GIS analysis of twenty-eight sub-watersheds in Massachusetts and considered five factors which the literature suggested influenced base flow. The literature suggested a positive relation between precipitation, forest cover and base flow and a negative relationship between impervious surfaces, soil drainage class, slope and base flow. A multiple regression analysis of the sub-watershed information confirmed the literature for two factors (soil drainage class and slope) and questioned it on three factors (impervious surfaces, precipitation, and forest cover). The resulting predictive equation indicated that imperviousness and precipitation were the most significant factors affecting base flow. The first derivative of the predictive equation indicated that the interaction effects between these factors had a substantial impact on the base flow values. A number of land use impacts were also considered in this research. Natural land use features such as open land, wetland, forest cover, agricultural, and recreation uses were found to promote the infiltration and increase base flow. These uses promote base flow because their surfaces are more pervious than unnatural surfaces such as high density/multi-family residential, industrial and commercial areas which are mostly covered by impervious surfaces reducing base flow. The research also used a case study of two Massachusetts sub-watersheds to consider the effectiveness of structural stormwater Best Management Practices for promoting base flow. Two sub-watersheds were considered: the Neponset where stormwater BMPs had been implemented and Quinsigamond that had not implemented them. The case study results suggested that structural stormwater BMPs were effective in increasing base flow.