Spring Water Budget of the Purchase College Bioswale.

Abstract

Roads, parking lots, and other impervious surfaces that cannot be infiltrated by water are a result of urbanization that increases the volume of stormwater runoff which negatively affects water bodies and urban soils. The conversion of grass and forest lands to impervious surfaces also impacts groundwater recharge and evapotranspiration. A bioswale constructed at SUNY Purchase College adjacent to the West 1 parking lot is a method of green infrastructure designed to recharge ground water by capturing and filtering stormwater runoff. This study aimed to determine if the bioswale at Purchase College receives enough water to maintain the necessary rate of evapotranspiration during the spring season. The quantitative movement of soil water in the bioswale was assessed by budgeting the amount of water that enters the study site through precipitation and exits through evapotranspiration. Over the course of the study, the sum of precipitation was greater than potential evapotranspiration by 28.4 mm. The lowest recorded storage water level of the bioswale was 29.4mm following the largest period of deficit recorded which lasted 17 days. Greater volumes and periods of surplus were recorded in comparison to deficit. Therefore, a drought never occurred and the bioswale received enough water to maintain the rate of evapotranspiration. However, this study does not cover a long enough period of time to experience drought conditions as it would be more likely to occur during summer months.