OBSERVATION OF TOTAL LOAD FROM A MOUNTAINOUS CATCHMENT AREA IN THE ABE RIVER

Abstract

In mountainous rivers, bed load, suspended load and washload are considered to flow at all depths. A Total Load Trapping Equipment system, capable of trapping all sediments within a unit width, was developed and placed at the Oshima check dam located upstream of the Abe River to measure sediment discharge. Based on four observations, the main results are as follows : (1) under normal flooding conditions, the ratio of suspended load plus washload to total load was nearly 80% or more and at times close to 100% in this river ; (2) the suspended load plus washload obtained was greater than that obtained at other rivers ; and (3) the bed load estimated using the Ashida-Takahashi-Mizuyama formula was greater than the measured amount in many cases, although the difference was smaller at peak flow. The bed load estimated using the Meyer-Peter-Muller formula was smaller than the measured quantity, but remained within one order when the sediment discharge increased.