This is an internal DOE Geothermal Program planning and control document. Many of these reports were issued only in draft form.

Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company (Westinghouse Hanford) are collaborating on a field study of the effects of gravel admixtures on plant growth and soil water storage in protective barriers. Protective barriers are engineered earthern covers designed to prevent water, plants, and animals from contacting buried waste and transporting contaminants to groundwater or the land surface. Some of the proposed designs include gravel admixtures or gravel mulches on the barrier surface to control soil loss by wind and runoff. The purpose of this study is to measure, in a field setting, the influence of surface gravel additions on soil water storage and plant cover. The study plots are located northwest of the Yakima Gate in the McGee Ranch old field. Here we report the status of work completed in FY 1989 on the creation of a data management system, a test of water application uniformity, field calibration of neutron moisture gages, and an analysis of the response of plants to various combinations of gravel admixtures and increased rainfall. 23 refs., 11 figs., 6 tabs.

Pacific Northwest Laboratory (PNL) is conducting the water-erosion control task of the Hanford Protective Barriers Program to assess barrier stability against soil erosion and slumping. The purpose of the barriers is to protect shallow-burial waste sites at the Hanford Site from water infiltration, biointrusion, and surficial erosion for up to 10,000 years. These aboveground, mounded structures will consist of layered, fine-grained sediment and rock designed to direct surface- and ground-water pathways away from the buried waste. The fine-grained sediment for the barrier will be obtained from the McGee Ranch on the Hanford Site. The purpose of the FY 1989 field work was to test two hypotheses concerning the behavior of McGee Ranch soil: runoff may occur on very dry, fine-grained sediment prior to complete saturation and rainsplash is an important erosional process for this type of sediment. This report describes plot construction, sediment sampling, and calibration testing of the rainfall simulator. Baseline stratigraphic and sedimentologic data include bulk density and textural properties of sediment in the test plots. Baseline precipitation data consist of predetermined raindrop sizes, rainfall intensities, plot coverage, and operational data for the simulator. 10 refs., 3 figs., 4 tabs.

This is an internal DOE Geothermal Program planning and control document. Many of these reports were issued only in draft form. (DJE -2005)