Hanford Site ground-water monitoring for 1992

Abstract

Monitoring activities were conducted to determine the distribution of radionuclides and hazardous chemicals present in ground water as a result of Hanford Site operations and, whenever possible, relate the distribution of these constituents to Site operations. A total of 720 wells were sampled during 1992 by all Hanford ground-water monitoring activities. The Ground-Water Surveillance Project prepared water-table maps of DOE`s Hanford Site for June 1992 from water-level elevations measured in 287 wells across the Hanford Site and outlying areas. These maps are used to infer ground-water flow directions and gradients for the interpretation of contaminant transport. Water levels beneath the 200 Areas decreased as much as 0.75 m (2.5 ft) between December 1991 and December 1992. Water levels in the Cold Creek Valley decreased approximately 0.5 m in that same period. The water table adjacent to the Columbia River along the Hanford Reach continues to respond significantly to fluctuations in river stage. These responses were observed in the 100 and 300 areas. The elevation of the ground-water mound beneath B Pond did not change significantly between December 1991 and December 1992. However, water levels from one well located at the center of the mound indicate a water-level rise of approximatelymore » 0.3 m (1 ft) during the last quarter of 1992. Water levels measured from unconfined aquifer wells north and east of the Columbia River in 1992 indicate that the primary source of recharge is from irrigation practices.« less