to the north and the fuel and target manufacturing facility ("M Area") to the west. In the headwater areas, the Tims Branch system is a "losing stream" (its base is above the water table and water seeps into the ground). As Tims Branch flows toward the confluence with Upper Three Runs, the stream elevation intersects the groundwater and it transitions to a "gaining stream" (water flows into the stream from the groundwater). Key morphological features relevant to potential studies in this stream include: 1) a rip-rap stabilized streambed "drop" followed by a catch basin, drain and overflow weir in the M Area outfall tributary ("outfall ditch"), 2) Steed's Pond (a former farm pond located approximately midway along Tims Branch which served as a sediment trap in the past but the dam is no longer present), and 3) several "beaver" dams and associated pools.