A growing problem in the western United States is the increasing demand on the water supply by urban development, agriculture, and resource conservation. This paper presents a hydrologic assessment of Arivaca watershed, a small rural watershed in southeastern Arizona. Project Goal: Estimate the potential groundwater recharge of the watershed. This project will use ARDBSN, a hydrologic simulation model, linked to ARC/INFO GIS to simulate the effects of stock tanks and various land use practices on the potential recharge of the watershed. GIS algorithms used in the project as well as the results of the study will be discussed.