根據近幾年的研究結果發現，越來越多的研究傾向將地理資訊系統與水資源模式作結合，充分利用地理資訊系統所提供之操作便利性、資料準確性、高處理效率且所展繪之圖面具有易讀性及親切性等優異的資料分析及展示功能，進行研究區域之環境背景資料建置與環境問題之分析探討。 大屯溪位於台灣西北部一未設流量測站之河川，本研究主要目標為以流域集水區之水平衡為基礎概念，並依據流域內歷年降雨量資料，結合地理資訊系統輔助擷 取所需之水文參數，求得此一小集水區內逕流、蒸發散、灌溉量、入滲量與迴歸水量。希冀藉由此一大屯溪流域之河川流量推估與各段河川內之生態基流量初步分析，作為一套水資源分析決策支援模式與探討。 推估結果顯示在河川流量方面，根據上中下游不同控制站的區域特性推估情況：在豐水期的五月到十月期間月平均流量約在12.11cms到60.24cms之間。枯水期的四月到十一月期間月平均流量約在3.68cms到18.27cms之間。可知大屯溪為豐枯水量差異極大的河川；生態基流量估算部份，依照河川流域內的不同特性，在中下游區位流速較高，不易符合Tennant法研究訂定之最低流速標準，須加以改善。 Ecological problem is concerned by many hydrological and water management studies. The combination of hydro science and geographic information system provides high preference of graph display and effective data integration. This study combines hydro science and geographic information system to analyze the ecological and hydrological management problem of Ta-Tun River Basin. Da-Tun River Basin located at west-north part of Taiwan. The aim of this research is to calculate the annual river flow. We are trying to get the hydraulic index such as runoff, evaportranspiration, infiltration, returned water and environmental flow assessments etc. by using GIS. We can try to build the Decision Support System and river basin model through GIS. ArcGIS is used for visualizing spatial data, performing spatial analysis, and creating maps to show the results of our research. According to the River Basin’s characteristics. which differs from control stations, the estimation result shows that Ta-Tun river has its characteristics.The assessment shows the different river section has different characteristics. This results shows the river flow is about 12.11cms to 60.24cms between May to October, and the rover flow is about 3.68cms to18.27cms between April to November. The Tennant method was used in this as the standard index to check study the correlation between the flow depth and flow velocity with ecological sustauability. The results show that the ecological flow indexes of the Ta-Tun river basin did not reach the suggest standard, further efforts are required to improve the current situation.
