A PRACTICAL EXPRESSION OF EFFICIENCY OF DETENTION STORAGES FOR POLLUTION AND WATER SUPPLY CONTROLS

First, an expression of efficiency of detention storages for water quality and supply controls, which was derived by the authors, is briefly explained. The expression contains several parameters, which represent characteristics of (1) rainfall time sequence, (2) land-use and (3) the storage-treatment system. The rainfall characteristics all over Japan are analyzed using data of AMeDAS, the automatic meteorological data acquisition system of the Japan Meteorological Agency, and, then, values of the parameters relating to the expression are summarized on the map of Japan with contours. A process of estimation of the efficiency by the proposed method is exemplified for a hypothetical and typical size of a house detention pond in the Tokyo area.