| 摘要: | 地下水是供應民生、工業及農業活動的重要資源之一。地下水與地表水的交互作用會導致水的供需以及品質的改變，因此對於區域水資源管理而言，瞭解地下水與地表水之間的交互行為是很重要的。過去以有許多研究利用不同假設與模式致力於地下水與地表水間交互作用的探討，其中GSFLOW (Groundwater - Surface water Flow)採用了過去模式的優點，並基於PRMS (Precipitation Runoff
Modeling System ) 與MODFLOW-2005 (Modular Groundwater Flow) 模式進行地下水與地表水間交互作用的探討，然而應用於大尺度與複雜問題時，產生MODFLOW-2005與PRMS模式的複雜輸入檔則是極為挑戰的議題。為了解決此問題，本研究目的有 (1) 利用GMS (Groundwater Modeling System) 介面評估MODFLOW-2005與MODFLOW-2000的兼容性，並利用四種不同網格情境挑選最適合的網格大小，這些情境包括不同網格細化方式，X、Y與Z方向分別切割不同網格大小，包含 20 x 30 x 2、60 x 90 x 2、 120x 180 x 2、與180 x 270 x 2的網格數目；(2) 利用觀測數據與穩態模擬結果驗證越南胡志明市西北地區的地下水位分佈；(3) 利用不同的MODFLOW-2005套件評估研究場址的水頭變化，水預算和輸入數據造成的影響；(4) 分析土壤的日貯蓄變化以及PRMS輸入參數對於研究場址的土壤和非飽和帶的影響。本研究的成果顯示 (1) 本研究能利用GMS介面的優勢將GSFLOW中MODFLOW-2000的輸入結合到GMS中的MODFLOW-2005，而研究指出最適合進行數值模擬的網格大小為120 x 180 x 2；(2) 在MODFLOW-2005中，輸入與輸出的貯蓄率差異會影響約50%、約-332.25 m3的研究場址內單位體積供需變化，研究區域內的水頭分佈從西北向東南逐漸減小，並在西部，南部和東南部出現小於2 m的水頭值；(3) 本研究利用PRMS得到了相似的土壤和非飽和帶貯蓄量變化，飽和與非飽和帶的土壤貯蓄量之中的流入貯蓄量分別為50.35 ％和50.04 ％，而輸出貯蓄量則分別是49.65％和49.96％，儲存量變化分別為3.34 m3和1379.44 m3。徑流和入滲係數的變化造成土壤貯蓄變化增加約6.89倍 (23.02 m3），但是土壤區域的參數變化則造成非飽和帶的貯蓄變化下降約0.47倍 (652.37 m3)。;Groundwater is one of the important water resources to supply domestic, industry and agriculture activities. Groundwater and surface water interactions can lead to the changes of water budget and water quality. The understanding of the surface water and groundwater interaction behaviors is critical for the regional water resources management. Efforts have been devoted on the issues of groundwater and surface water interactions by using different approaches and various models. Taking advantages of recent studies in developing groundwater models, the Groundwater - Surface water Flow (GSFLOW) model based on the integrations of the Precipitation Runoff Modeling System (PRMS) and the Modular Groundwater Flow (MODFLOW-2005) model is developed to account for interactions between surface water and groundwater flows. However, the text input formats in MODFLOW-2005 and PRMS has limited the implementation of GSFLOW to practical problems with large-scale domains and complex parameter distributions. The objectives of the study are (1) to evaluate the compatibility of MODFLOW-2005 and MODFLOW-2000 based on Groundwater Modeling System (GMS) interface, and to evaluate suitable cell sizes by four testing cases, including the numbers of cells 20x30x2, 60x90x2, 120x180x2, and 180x270x2, in x, y, and z directions, (2) to validate the groundwater levels between observed data and steady-state simulated results in the northwest area of Ho Chi Minh-Vietnam, (3) to assess head variations, water budgets, and the particular effects of input data in various packages of MODFLOW-2005 for the study site, and (4) to analyze daily variations of storage changes, and effects of PRMS input parameters on soil and unsaturated zones at the study area. The results of the study show that (1) the study can take the advantage of GMS interface to incorporate inputs of MODFLOW-2000 in GMS for MODFLOW-2005 in GSFLOW. The suitable cells size of numerical simulations is 120 rows, 180 columns, and two layers for the study area. (2) In MODFLOW-2005, the volumetric budget of study area is influenced approximately 50 % for input and output storage, and -332.25 m3 for the difference of input and output storages. The head distribution decreases from northwest to southeast with low head values less than 2 m in west, south, and southeast of study area. (3) In PRMS, similar variation of soil and unsaturated zonal storages are obtained. The soil and unsaturated zonal storages are 50.35 % and 50.04 % for input storage, 49.65 % and 49.96 % for output storage, and 3.34 m3 and 1379.44 m3 for storage change, respectively. The alterations of runoff and infiltration parameters increase up to 6.89 times of storage changes (23.02 m3) in soil zone, and the changes of soil zone parameters decrease down to 0.47 times of storage changes (652.37 m3) in the unsaturated zone. |
