屏東平原地下水流灰色模式分析

Grey Model Analysis of Groundwater Flow in Pingtung Plain

張聖麒

指導教授 ： 葉一隆

國立屏東科技大學/工學院/土木工程系所/碩士(2007年)

https://doi.org/10.6346/NPUST.2007.00009

摘要

地下水位變化受邊界條件與地質條件等因素影響，而這些因素之信息具隨機性與模糊性，故地下水流系統可視為一灰色系統。本文使用灰色水力傳導係數將達西定律推展成灰色達西定律，利用灰色達西定律與質量守恆定理推導出灰色地下水流方程式，並利用有限元素法離散控制方程式且使用C語言撰寫成灰色數值模式。灰色有限元素模式對於現地的地質之非均質性分佈所使用之參數值是一區間值，比將地下水流系統視為白色系統，使用單一參數值之誤判而造成錯誤，更符合現地的狀況，因此利用灰色數值模式來分析屏東平原地下水流況，可知變異的範圍，將可使地下水資源利用之規劃與決策更具彈性。本研究利用灰色數值模式針對1996及1997年進行屏東平原地下水模擬，並與實際地下水位觀測值結果比較，以探討各鄉鎮之淨補注量情形。由分析結果可知1997年豐水期所模擬的淨補注量比1996年的大，而枯水期淨抽水量亦比1996年的大；由分析亦可得知枋寮鄉、高樹鄉、萬巒鄉及新埤鄉在此二年的淨補注量是1997年會比1996年多，主要是1997年的降雨量比1996年多，而且此四個鄉鎮靠近東邊的側向補注區，會受到側向補注量及水力傳導係數的影響，造成地下水位變動較大。

關鍵字

灰色度 ； 地下水位 ； 不確定性 ； 屏東平原

並列摘要

Since the variation in groundwater heads is affected by boundary types and geologic conditions, which contain random and obscure characteristics, a groundwater flow system can be regarded as a grey system. This study incorporated grey hydraulic conductivity into Darcy’s law, which was expanded to become the grey Darcy’s law. Furthermore, the grey groundwater flow equation was derived from combining the grey Darcy’s law and Mass Conservation theory. The grey numerical computation model was written in C software and utilized a discretely controlled equation with the finite element method. The parameters of the heterogeneous distribution in the field were represented with an interval in the grey finite element model that can reduce errors when compared with a white system that used point values to represent the parameters. Furthermore, the parameter values were represented with an interval that conformed to the field conditions. This research used simulated groundwater flows conditions from both 1996 and 1997 in Pingtung Plain. The grey numerical model variables were compared to the observed groundwater levels in the fields to determine the net amount of recharge in various villages and towns. The results showed that the net amount of recharge in 1997 was larger than in 1996 in the wet seasons; however, the net amount of discharge in 1996 was larger than in 1997 in the dry seasons. In addition, the results showed that the net amount of recharge and discharge were different in four townships, FangLiau, Gaushu, WanLuan, and SinPi during these two years. The difference was due to more rainfall in 1997 than in 1996. Additionally, these four townships are located in the eastside of the lateral recharge area that have variable recharge, hydraulic conductivity, and variation of groundwater levels. This research showed that the analysis of groundwater flow conditions with the grey numerical model can obtain the ranges of variation that would make the planning and decision making of groundwater resources more flexible.

並列關鍵字

Grey degree ； Groundwater level ； Uncertainty ； Pingtung plain

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