| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1987: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1986: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
The efficiency of storages for flood control is analyzed.When both drainage and storage facilities are used,the risk or frequency of flooding in a flood control system must be evaluated based on the joint frequency distribution of the"peak discharge"and the"total runoff"of a flood.Using the joint frequency distribution,the autors derived an expression of the contour of frequency of flooding on a plane on which the lateral and vertical axes respectively represent capacities of a drainage and a storage facilities.This contour is called the"equi-risk line".The results of the theoretical analysis are being applied to risk evaluation in flood control,by existing and planned storages in Osaka and Tokyo,Japan.
Then,another theory was presented for non-point pollutant control in urbanized basings.There are several alternative plans to reduce the volume of storm-generated non-point pollutant runoff to lakes and ponds.One of the most effective is to store flood runoff temporarily in storage facilities,and treat and release it to natural waters during periods of no precipitation.The efficiency of storage-treatment systems is usually evaluated by simulations of runoff,storage,and treatment processes with observed rainfall sequences as inputs.The authors presented a simple expression of efficiency of these storage treatment systems.
These expressions have some parameters,which represent meteorological and runoff characteristics of a basin,and capacities of the facilities.Using AMeDAS,the values of the meteorological parameters in the expressions are calculated,and displayed on the maps of Japan with contour lines.
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