[A-HW25] 都市域の地下水・環境地質

★ [AHW25-P01] 甲府盆地の地下水資源評価に向けた水収支解析

ポスター講演3分口頭発表枠

*市川 温¹、高部 裕也²、中村 高志³、馬籠 純³、石平 博³ (1.京都大学大学院工学研究科、2.山梨大学大学院医学工学総合教育部、3.山梨大学国際流域環境研究センター)

キーワード：水収支, 地下水資源, 甲府盆地

Water use in Yamanashi Prefecture is highly dependent on groundwater resources, and a number of groundwater investigations have been carried out. However, groundwater recharge, which is the most crucial factor for its proper management, remains uncertain. This study conducted a water balance analysis of Kofu basin aiming at assessment of its groundwater resources. The water balance of Kofu basin consists of temporal change of groundwater and surface water amount, precipitation, river and groundwater discharge coming from the surrounding mountain regions, evapotranspiration and river discharge going out from the outlet of the basin. The observation datasets were utilized to estimate precipitation and river discharge. An advection-aridity approach was used to estimate actual evapotranspiration. The temporal change of groundwater amount was found to be small enough to be ignored compared other components based on groundwater level observations and the temporal change of surface water was assumed to be negligible. Groundwater inflow from the surrounding areas was estimated as difference of other inflow and outflow components. The annual amounts of each components per unit area of Kofu basin were estimated as follows; precipitation: 1090mm, river inflow: 5090mm, evapotranspiration: 340mm, river outflow: 6500mm, groundwater inflow: 650mm.