應用集水區水文模式SWMM評估德基水庫集水區之水資源涵養量

Application of a Stormwater Management Model (SWMM) to Assess the Water Resource Conservation Capability in the Deji Reservoir Watershed

曾俊偉(Chun-Wei Tseng) ； 陳起鳳(Chi-Feng Chen) ； 吳憶茹(Yi-Ru Wu) ； 林鎮洋(Jen-Yang Lin)

《台灣林業科學》 35卷2期 (2020/06) Pp. 103-121

https://doi.org/10.7075/TJFS.202006_35(2).0001

摘要

集水區之水資源涵養量計算方法雖有土壤孔隙率、水文平衡收支法、基流資料估值法及消退曲線位移法等計算方法，但多屬於靜態計算單一時期的水資源涵養量，較無法推估全年度或全集水區尺度之水資源涵養量。有鑑於此，本研究利用集水區水文模式SWMM（暴雨逕流管理模式），以集水區尺度動態模擬評估集水區內之年水資源涵養能力，以及土地利用型態變遷所造成的影響。研究區域為大甲溪上游之德基水庫集水區，藉由德基水庫集水區共4年期之土地利用型態變遷分析與相關氣象水文資料建置SWMM水文模式，進而推估集水區土地利用型態變遷對水資源涵養量的影響。研究結果顯示，集水區內之森林土地利用型態比例較多則可增加水資源涵養能力，德基水庫集水區約61%的年降雨量不隨逕流流出，而涵養於集水區中。然而，土壤中的水資源涵養量會受到如降雨量、降雨強度、地質、坡度等各種環境因素所影響，本研究針對降雨量以及土地利用型態探討水資源涵養量的變化，採用2009年及2010年度之降雨量資料進行水資源涵養量分析結果顯示，不同降雨型態對水資源涵養量的影響較土地利用型態變遷的影響大，但於同一種降雨型態下，不同土地利用型態對水資源涵養量也有明顯影響。

關鍵字

SWMM水文模式 ； 動態模擬 ； 土地利用型態變遷 ； 水資源涵養量

並列摘要

Water resource conservation can be calculated with soil porosity, a water balance method, base flow estimation, and a depletion curve method. However, most of these belong to static state calculations in a single period. This study used the Stormwater Management Model (SWMM). The SWMM can dynamically simulate the water resource conservation capability with land-use changes, and determine the impacts of land-use changes in the study area. The research area of the Deji Reservoir was the upstream portion of the Dajia River. Meteorological, hydrological, and landuse data were gathered, and 4 yr of land-use changes were put in the SWMM model to analyze the Deji Reservoir water resource conservation. Furthermore, impacts of land-use changes on water resources conservation changes were also estimated. Results showed that when the proportion of forest land use was higher, the resource conservation capacity was higher. About 61% of the annual rainfall was conserved in the watershed of the Deji Reservoir. Water resource conservation can be more finely calculated in the future, for example, using different kinds of trees. In addition, water resource conservation is affected by various factors, such as rainfall, the rainfall intensity, geology, slope, etc. This study used rainfall data from 2009 and 2010 to analyze water resource conservation. Results showed that the impacts of different rainfall patterns on water resource conservation were greater than those of land-use changes. Under the same rainfall pattern, different land uses also had an obvious influence on the amount of nutrients.

並列關鍵字

stormwater management model ； dynamic simulation ； land-use change ； water resource conservation capability