金門地區地面水與地下水聯合運用

Conjunctive Use of Surface and Groundwater in Kinmen

洪有仁(Yu-Jen Hung)

指導教授 ： 劉振宇

國立臺灣大學/生物資源暨農學院/生物環境系統工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01424

摘要

為解決金門地區缺水問題及防止地下水含水層之海水入侵，本研究模擬分析各種情境之供水策略並提出金門地區地面水與地下水聯合運用方案供決策者參考，首先藉由地下水模式(MODFLOW)模擬出金門地區豐水年、平水年與枯水年之地下水水位變化，並藉此模式推求出豐、平、枯水年之安全出水量各為1460萬噸、1182萬噸及970萬噸，然後利用此模式分析各分區含水層之抽水量與地下水位變化關係，並求出月響應矩陣之係數，再利用線性規劃法，將所需目標函數與限制式等轉化成數學式。
目標函數為最小水位洩降值，限制式包括地下水抽水量及水位洩降之響應矩陣、地面水供水量、地下水供水量及需水量等，依此數理模式提出四項情境分析，再利用LINGO軟體求解各情境之最小水位洩降及各區可增抽水量，情境A則模擬海水淡化廠未如期完工，地下水總增抽量為42.96萬噸/年之結果顯示金西地區較金東地區適合增抽；情境B則模擬浚渫工程影響金東地區供水，改以金西地下水提供85.5萬噸/半年之地下水增抽量供給金東地區湖庫用水，結果顯示金西地區地下水位KM-001(湖埔國小)與KM-005(金門高中)在模擬期末均下降至海平面以上3.5公尺左右；情境C則模擬金門地區湖庫受藻類優養化影響供水，並改以金西地下水提供141.3萬噸/半年之地下水增抽量供給金東地區用水，結果顯示同樣在金西地區地下水位KM-001(湖埔國小)與KM-005(金門高中)在模擬期末均下降至海平面以上1公尺左右；最後在情境D則模擬金門地區之湖庫受到人為毒物污染，必須以金西地下水提供348萬噸/年之地下水增抽量供給金東地區用水，則結果顯示在金西地區大部分區域地下水水位皆已低於海平面。
本研究建議金東地區未來可疏浚原有供水湖庫或擴建海水淡化廠，而在缺水量不大時可經由輸水管線由金西地區增抽地下水供應，但必須考慮金西各分區最大可增抽之限制量，以避免造成當地含水層之海水入侵。

關鍵字

金門 ； 聯合運用 ； 響應矩陣 ； 地下水 ； MODFLOW

並列摘要

In order to resolve the problem of water shortage and avoid saltwater intrusion in Kinmen, this study used linear programming method to simulate various scenarios of water supply problems and proposed corresponding strategies associated with the conjunctive use of surface and groundwater. The numerical model, MODFLOW, was used to simulate groundwater level charges and estimate the groundwater safe yield in the wet, average and dry years in Kinmen. The analyze results revealed that the safe yields were 14.6, 11.82 and 9.7 million tons for the wet, average and dry years, respectively. A response matrix which links monthly pumping and drawdown was established based on the MODFLOW simulation.
The objective function was set to minimize drawdown which constrained by the response matrix, surface water supply, groundwater supply and total demand, and solved by LINGO. Four scenarios were investigated： Scenario A was a delay of desalination plant construction, resulting a 4.296×105 tons/year water shortage; Scenario B was a dredging works influenced the water supply in eastern Kinmen and resulting a 8.55×105 tons/half-year water shortage; Scenario C was the eutrophication of reservoirs influenced the water supply in eastern Kinmen resulting a 14.13×105 tons/half-year water shortage. The results of scenarios A, B and C show that the largest ground water table drop found in wells KM-001 and KM-005 were all above the sea level. However, in the Scenario D where the reservoirs water has been poison and resulting a 34.8×105 tons/year water shortage, the analytical results indicate that groundwater levels in most western Kinmen are lower than sea level at the end of year. The pumping of 34.8×105 tons/yr exceeds the safe yield of the groundwater and extensive saltwater intrusion may develop in western Kinmen.
Additionally, this work suggests that surface reservoirs dredging and construction of desalination plants should be carried out to supply the future water need in eastern Kimen. Furthermore, the groundwater in western Kinmen can supply partially water-needs in the eastern Kinmen using pipeline connection. However, the safe yield should not be exceeded to avoid seawater intrusion.

並列關鍵字

Kinmen ； conjunctive use ； response matrix ； groundwater ； MODFLOW

參考文獻

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