PLAN EVALUATION METHOD FOR INVESTMENT IN RAINFALL OBSERVATION FACILITIES

摘要

PROBLEM TO BE SOLVED: To provide an evaluation method that can contribute to optimal facilities investment planning, covering the review of the positions of rainfall radar installation and the addition of ground level rain gauges, by taking into consideration the mutually complementary relationship between the rainfall radars and the ground level rain gauges in evaluating a plan for investment in rainfall observation facilities.SOLUTION: A rainfall observation facility 1 comprises a rainfall radar 2 arranged in desired positions away from dam basins and ground level rain gauges 3 arranged within the dam basins; under a condition that a beam from the rainfall radar 2 is emitted at the minimum elevation angle α at which the beam can go over a topographic obstacle existing on the way of the beam toward the dam basins by classifying the dam basins by the beam height that permits reaching a targeted dam basin, the dam basin of each class is subdivided into subclasses of basins served by a dam in each sub-basin by the density of ground level rain gauges installed, which is the quotient of division of the number of the ground level rain gauges 3 by the remaining basin area, and a plan of investing in the rainfall observation facility 1 is evaluated from the relationship between the class according to the beam height and the sub-class according to the density of ground level rain gauges installed.