以多變數判別方法區分濁水溪沖積平原需要維護之地下水監測井

地下水監測井長期與水接觸，井管金屬材料穩定度受地下水水質影響，可能產生微生物－化學性的腐蝕與淤積。但是產生問題的井壁，由於在地下，很難評估。本研究以深井攝影裝置，觀測濁水溪冲積扇之地下水監測井十五口，並根據各井地下水質資料以判别分析法建立區分函數，再去分區該地區所有檢測地下水質五十二口之監測井，以判斷各井需要清洗的緩急性。分析的結果顯示該地區有十八口監測井，是急需清洗，其地下水質的汚染特徵是水中有較高的硝酸鹽，導致地下水井井壁上微生物的滋生；另外十七口需要清洗的水井水中的鹽分、鈣、鎂濃度較高，在井管面形成抗腐蝕性的保護膜，可以不需要立刻清洗。因此監測井在清洗前後都必須判斷保護膜是否存在，才可以進行清洗，監測井在清洗前後都必須加氯殺菌，以維持清洗之期效。

關鍵字

地下水質；監測井

並列摘要

Groundwater monitoring wells have contacts with water constantly, and stability of metal materials has been effected by groundwater quality. Microorganism and electrical chemistry reaction may cause clogging and corrosion on metal surface. However, it is very difficult to evaluate performance of monitoring well due to the depth of the well. The purpose of this study is to arrange priority of well cleaning of fifty-two wells by photo graphic device and statistical discriminate analysis. Discriminate analysis is applied to classify three different groups: well need to be cleaned immediately, in the future, and unnecessary to clean. As a result, eighteen monitoring wells need to be cleaned immediately due to higher nitrate concentration in groundwater. Micro-organism growth in nitrogen over-fertilization is found to be the most significant factor contribute to well clogging and corrosion in our investigation area. Seventeen monitoring wells were classified to be cleaned in the future. Water quality in these wells contain hight salt, calcium and magnesium concentrations, which may form anticorrosive film on well surface to prevent bacterial and electrical corrosion. Since bacteria is the most important factor to cause monitoring well problems, it is required to add chlorine during the cleacing process.

並列關鍵字

Groundwater quality ； Monitoring well

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