Rio Blanco Oil Shale Company has been conducing environmental monitoring studies on Tract C-a since the completion of baseline and interim period inventory studies on September 30, 1977. The monitoring studies have been conducted to assess the impact of oil shale operations on Tract C-a and the vicinity as development progresses. Prior to October 13, 1980, however, the development was confined to surface disturbances in a relatively small area related to construction activities, and dewatering the reinjection. Therefore the data collected between October 1, 1977 and October 13, 1980 are largely indicative of baseline conditions.