Quantitative Analysis of Groundwater Effluent and Reservoir-Water Influent in a Small Pond Using 222Rn- and Water-Balance Equations

JARQ : Japan Agricultural Research Quarterly
ISSN 00213551
書誌レコードID(総合目録DB) AA0068709X
38-04-06.pdf198.34 KB

Percolation of water from a pond may cause a landslide in a hilled rural area. Before measures to prevent such landslides can be planned, it is essential to identify reservoir-water influent from the pond. We describe an analytical method that uses 222Rn- and water-balance equations to quantify groundwater effluent and reservoir-water influent simultaneously, which is impossible using the conventional method that measures only surface-water inflow and outflow. We selected F pond, Nagano Prefecture, as the study site. We estimated the rate of 222Rn dispersion to the atmosphere by assuming a stagnant film between water and air with thickness inversely proportional to the rate of dispersion. By a laboratory experiment, we estimated the film to be about 830 ?m thick and found that the film thickness was not influenced by wind velocities less than 1.5 m s-1. A preliminary investigation suggested that reservoir-water was mixed very well. The groundwater effluent and the reservoir-water influent during the investigation were calculated to be 0.67 × 10-3 m3 s-1 and 0.41 × 10-3 m3 s-1 respectively, by making 222Rn- and water-balance equations and solving them. This analytical method is expected to be useful for not only prevention of a landslide but also for effective use of water and prediction of water quality.

作成者 HAMADA Hiromasa KISHI Satoru

stagnant film


公開者 Japan International Research Center for Agricultural Sciences
国立情報学研究所メタデータ主題語彙集(資源タイプ) Journal Article
開始ページ 253
終了ページ 258
DOI 10.6090/jarq.38.253
権利 Japan International Research Center for Agricultural Sciences
言語 eng