流域スケールの土地の乾湿および浅層地下水流動予察のための地形学的手法

概要

論文の詳細を見る
Typical arrangement patterns of "L1" and "upland" were found to be feasible topographic measures for predicting the flow system and fluidity of shallow groundwater in Lowlands including fans. L1 is defined as the latest depositional surface of about 20,000 yr B.P., and is the oldest of geomorphic surface in the lowlands. The other younger surfaces are of erosional origin, and are consist of subsurface layers with a much higher permeability than L1. Accordingly, the arrangement patterns of L1 effectively control the flow systems of lowland shallow groundwater. The arrangement patterns, varying according to subsidence, were classified into three categories : "opened downstream", "closed downstream" and "buried", and corresponded to "divergent", "convergent" and "divergent" flow systems, respectively. The uplands also vary in arrangement from "normal" to "buried" patterns according to the subsidence. For the "intermediate" pattern between them, a row of uplands is arranged at the distal fan, and is accompanied by a shallow basinlike geologic structure from the proximal to the middle fans, where the clayey upland-soil is buried and acts as an aquiclude, obstructing both seepage and the downward discharge of groundwater. Thus, the distal upland row can be a distinct evaluation criterion of its low fluidity.
日本ペドロジー学会の論文
2003-06-30