No.238 研究課題 / Project
GISを用いた多摩川・鶴見川流域における水循環モデルの構築Simulation of Water Pollution caused by Urbanization, and Development of Hydrologic Cycle Model for the Tama River and the Tsurumi River Basins using GIS| 学術研究 Academic Research |
No.238 |
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| 代表研究者 Principal Investigator |
原 美登里 Midori Hara |
| 所属（採択当時） Affiliation |
東京大学空間情報科学センター客員研究員 Kyorin University |
| 研究内容要約 Research Summary |
古来より貴重な水源とされた多摩川・鶴見川流域が、どのように変化してき たのかを明らかにすることは、流域の水環境の復元や、水質を論じるうえにお いても有用であると考えられる。 本調査・研究は従来の水環境研究・水資源研究の基礎データである流量・取 水量・排水量・水質などのデータや、人口・土地利用などの人文データをコン ピューターにより整理・データベース化しており、これらは総合的な多摩川・ 鶴見川流域の環境浄化研究に汎用・活用されると考える。 また、今までは個別に保存されていた地図とデータを統合し、また調査結果 はコンピューター上でGISを用いて視覚的に表現してあるため、一般の人にも分 かりやすい。 We collected data on population, land use, water supply and water quality in the Tsurumi River basin within Kanagawa Prefecture, and organized them by developing a database. Then, based on the data collected from the Tsurumi River basin within Kanagawa Prefecture, we created a comprehensive map-based database. Changes in land use in the Tsurumi River basin from 1967 to 1990 clearly show a rapid increase in urban land use such as housing land, and a continuous decrease in permeable land such as agricultural areas, as well as forests and plains. In 1967, permeable land such as forests and agricultural areas covered much of the basin, while in 1990 most parts of the basin had been transformed into urban land use such as housing and industrial land. The Tsurumi River basin had about five times as large a population in 1990 as in 1960. Along with this phenomenon, a water-supply coverage rate also increased. On the other hand, there was no sewerage in 1960, according to data on sewerage coverage rates, which are closely associated with river pollution. Though the sewerage coverage rate has been increasing since then, raw sewage is still dumped without treatment in some areas. This is believed to have had a significant adverse effect on the water quality of the Tsurumi River. The same is true of the Tama River basin. Like in the Tsurumi River basin, there was a delay in the development of sewerage systems in the Tama River basin, despite rapid increases in the population and the supply of urban water. The delay resulted in the severe pollution of the Tama River system. According to year-to-year changes in data on the water quality of the Tsurumi River basin, an improvement tendency can be seen from BOD (which seems to have caused by the increase in the sewerage coverage rate), while pollution loading amount showed an increasing tendency. An increasing amount of wastewater (both treated and untreated water) was discharged into the Tsurumi River year by year, indicating that loading amount to the Tsurumi River was increasing. We investigated the Nikaryo Yosui Canal in order to evaluate pollution level in the Tsurumi River basin. It indicated that the amount of water in the canal was significantly smaller than before. This was associated with sewerage development, which caused a smaller amount of water to flow into the canal. A decrease in the amount of water in the Nikaryo Yosui Canal means a decrease in the amount of water in the Tama River. The self-purification of rivers is dependent on the amount of river water; therefore, we believe that the decrease in the amount of river water is related to the pollution of the Tama River system |
| 共同研究者 Collaborators |
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| 研究全文 Full Text |
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