DESIRABLE RANGE OF DIMENSIONLESS WIDTH AND DEPTH VERSUS DIMENSIONLESS DISCHARGE AND APPLICATION TO RIVERS AT DESIGN AND IMPROVEMENT STAGES

Abstract

It is an important issue to determine the river cross-section which is satisfied with functions of the flood control and the river environment. Fukuoka has derived the relationships of dimensionless width and depth versus dimensionless discharge considering floods and river basin characteristics.The purpose of this study is to show the application method of Fukuoka's equation to rivers at design and improvement stages. At first, we determine desirable range which dimensionless width and depth versus dimensionless discharge holds for rivers with various cross-sections. Secondly, we suggest that river width and cross section at an improvement stage should be improved up to the safety level of 1/30.