Description: A prototype Hanford barrier was deployed over the 216-B-57 Crib at the Hanford Site in 1994 to prevent percolation through the underlying waste and to minimize spreading of buried contaminants. This barrier is being monitored to evaluate physical and hydrologic performance at the field scale. This report summarizes data collected during the period FY 2005 through FY 2007. In FY 2007, monitoring of the prototype Hanford barrier focused on barrier stability, vegetative cover, evidence of plant and animal intrusion, and the main components of the water balance, including precipitation, runoff, storage, drainage, and deep percolation. Owing to a hiatus in funding in FY 2005 through 2006, data collected were limited to automated measurements of the water-balance components. For the reporting period (October 2004 through September 2007) precipitation amount and distribution were close to normal. The cumulative amount of water received from October 1994 through September 2007 was 3043.45 mm on the northern half of the barrier, which is the formerly irrigated treatment, and 2370.58 mm on the southern, non-irrigated treatments. Water storage continued to show a cyclic pattern, increasing in the winter and declining in the spring and summer to a lower limit of around 100 mm in response to evapotranspiration. The 600-mm design storage has never been exceeded. For the reporting period, the total drainage from the soil-covered plots ranged from near zero amounts under the soil-covered plots to almost 20 mm under the side slopes. Over the 13-yr monitoring period, side slope drainage accounted for about 20 percent of total precipitation while the soil-covered plots account for only 0.12 mm total. Above-asphalt and below-asphalt moisture measurements show no evidence of deep percolation of water. Topographic surveys show the barrier and protective side slopes to be stable. Plant surveys show a relatively high coverage of native plants still persists …
Date: February 1, 2008
Creator: Ward, Andy L.; Link, Steven O.; Strickland, Christopher E.; Draper, Kathryn E. & Clayton, Ray E.
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