Recharge estimate for the Hanford Site 200 Areas plateau

An evaluation was made to assess the magnitude of recharge from natural precipitation on the Hanford Site 200 Areas plateau. Two sources of data were used in the evaluation moisture accumulation in a 200 East Area closed-bottom lysimeter for 13 yr, and distribution of 137Cs in a solid-waste trench in which contaminated soil had been buried for 10 yr. Cesium-137 contaminated soil was placed in a solid-waste burial ground. After 10 yr, the distribution of 137Cs detected beneath the trench bottom above the background radiation level. Thus, there was no measurable downward recharge. However, 137Cs was detected above the trench suggesting negative recharge. In summary, the recharge rate was found to be zero or negative, within the estimated error of measurement, for two locations on the Hanford Site 200 Areas plateau. 11 refs., 5 figs