A critical flow flume and several temporary gaging stations were installed on the site to characterize the surface water system. The site is drained by a central stream that flows into Melton Branch. Two smaller tributaries are located on either side of the site. The site lies within the White Oak Creek watershed, thus drainage from the site is monitored by the established system for the drainage basin. A monitoring well network of 18 wells was installed on site to characterize the groundwater flow regime and to collect data on the aquifer properties. The aquifer underlying the site is relatively low in permeability (2.57 x 10/sup -5/ cm/sec), anisotropic, and flow is controlled by the secondary porosity formed by the pervasive jointing. The surrounding tributaries are the local discharge areas for the groundwater system, but, based on the water budget and the geologic investigations, it appears that part of the groundwater discharge may directly enter Melton Branch. Water samples collected from the wells and streams indicate that the site is uncontaminated by surrounding activities on the ORR. 47 references, 34 figures, 15 tables.