都市域における浅層地下水涵養源の同位体水文学的考察
スポンサーリンク
概要
- 論文の詳細を見る
As well as reducing groundwater recharge by precipitation, urbanization creates a new important source of water for groundwater recharge, that is mains leakage. Although it has been realized by a water balance method that urban groundwater recharge is often as high, or higher, than pre-urbanization rates owing to the downward percolation of mains leakage, the increases have rarely been quantified in a direct manner. In this study, contribution of mains leakage to the discharge of springs in the Kurome River basin and Shakujii River basin, both in Tokyo, were evaluated through a comparison among the δD and δ<SUP>18</SUP>O of spring water and mains leakage (tap water). In the moderately-urbanized Kurome River basin, all the springs represented almost 100% precipitation contribution. This is also the case in the more urbanized upper reaches of the Shakujii River basin, where precipitation alone could account for 85-100% of the discharge of springs. Precipitation was found to play a less important role in spring discharge in the highly-urbanized lower reaches of the Shakujii River basin (impermeable surface ratio: some 0.8 and more), were some springs contained substantial proportions of mains leakage of as much as 30-70%. On the other hand, it is worthy of notice here that, even in central Tokyo, the isotopic composition of most spring waters was indicative of predominant contribution of precipitation, which is contrary to the results of the previous studies on the basis of a water balance method.
- 日本水文科学会の論文
日本水文科学会 | 論文
- 山地源流域の湧水の形成過程に及ぼす岩盤地下水の影響
- 湖水の循環と混合
- 日本水文科学会ハワイ火山水文巡検報告(その3)マウイ島のUSGSの実験流域
- 日本水文科学会ハワイ火山水文巡検報告(その2)マウイ島の自然環境と水利用
- 富士山周辺の湧水および地下水の水質について