ABSTRACT
ABSTRACT: The authors carried out a series of studies of the water balance in the Isawa-gawa alluvial fan, Iwate Prefecture, Northeast Japan. The study focuses on generating basic data that can help towards the sustainable use of groundwater as well as the general management of both surface water and groundwater. Specifically, studies have been carried out to (a) prepare a model of the topographical features of this fan, (b) understand the water balance between groundwater in the widespread aquifer of the fan and the rivers Isawa-gawa and Kitakami-gawa, and (c) speculate on the prospect of the future water balance between surface water and groundwater. As a result, the authors understood the hydrogeomorphological and hydrogeological outline of the Isawa-gawa alluvial fan. Hydraulic simulations suggest that the effect of global warming on the water balance of the Isawa-gawa alluvial fan will be relatively small, although the level and storage of groundwater (recharge-discharge) will fall from spring to autumn, whilst the increases of precipitation and thawing will increase them from autumn to spring.
