Dynamics of 137Cs bottom contamination of the Tsimlyanskoe reservoir

Analysis of data obtained in 1990 and 2000 on the 137Cs contamination of the bottom of the Tsimlyanskoe reservoir near the dam has revealed the salient variations of this contamination. The global fallout enters the water in the section near the dam from side tributaries and as a result of erosion from the closest water catchment areas. The fallout due to the accident at the Chernobyl nuclear power plant is added primarily with the solid runoff from the more highly contaminated catchment basins of the Don River. It is shown that shore abrasion, flows, and removal of sediment through the water outflow area influence the distribution of the 137Cs content over the zones and the characteristics of the variation of this distribution in time.