Reconstruction of the Kyu-kitakami River Diversion Facility and Consideration for the Environment

Abstract

The discharge of the Kitakami River fluctuates very sharply, from just a few m³ / sec during dry periods to about 4000 m³ / sec following a typhoon. During times of drought or extended dry periods the water in the estuarine area becomes oxygen-deficient., which adversely affects the Yamato-shijimi; heavy flows from the Kitakami River also have an impact on the cultivation of marine species in Oppa Bay.This report describes how we used numerical simulation models and observations of currents, water temperature, DO, salinity, SS etc., to estimate the influence of the river flow during periods of heavy flow and the reduction in oxygen-deficiency attributable to the diversion facility.