山坡地區遇上連日豪雨時,不但引起土壤沖蝕和山崩,更易造成逕流集中,使洪峰逕流量大幅增加,帶來下游地區嚴重洪水及泥砂災害。而雨水貯集可以有效的減少逕流量,進而達到防洪減災的效果,而所收集來的雨水也可以做進一步的利用,如缺水時可引至農田灌溉,或者也可以引至社區作爲澆花、洗車、沖廁等用途,達到水資源的有效利用。本研究選擇汐止市爲模擬對象,利用地理資訊系統(GIS)及農業非點源污染模式(AGNPS)模擬分析出合適的雨水貯集設施設置地點。
本研究設計在一定之逕流量、輸砂量、及坡度等適合設置雨水貯集設施限制條件,利用AGNPS的特性,由電腦幫我們篩選出符合限制條件的地點。本研究一共在研究區526個方格中找到36個方格符合設置雨水貯集設施之地點,這些方格絕大部分都分佈在集水區的上游地區。因此確信可以利用AGNPS模式來做爲自動選址的方法,以節省大量的人力、物力及時間。
Torrential rain in slope land area, not only cause soil erosion but also landslide, even cause more runoff to concentrate and increase flood peak runoff, and deliver severe soil and sand calamity in downstream areas. Rainwater catchment, however, can reduce runoff, control flood and decrease calamity. Collected rainwater can be further utilized, for example, to irrigate farmland, for landscaping or car wash. It can achieve effective water resource use. This study selected Hsichih County and used GIS as well as AGNPS model to determine suitable sites to set up rainwater catchment systems.
Criteria to select the rainwater catchment sites are based on, runoff volume, sediment yield and land slope. From the AGNPS output, we can decide the best sites to install rainwater catchment systems. Out of 526 cells, 36 cells were selected. These cells are distributed in the upstream area. The AGNPS model may also automatically determine the best sites, which can save a great deal of manpower, resources and time.