本文旨在探討後村圳灌溉區內爭水事件的歷史變遷過程，究明爭水性質發生轉變的過程及原因。後村圳是由清治時期開鑿的張厝圳及劉厝圳，於日治時期為臺灣總督府合併後而形成的水利系統，張厝圳及劉厝圳從開鑿之初即發生爭奪圳頭用地的訴訟事件，其後因圳道混雜、水權不明而衝突不斷，旱季時圳頭及圳尾地區的爭水事件頻傳；日治時期，臺灣總督府為發展農業生產，以公權力介入傳統水利運作，成立具公法人性格的水利組織，並以先進工程技術改建埤圳設施，灌溉水量的供應穩定得以確保。其後，總督府為了擴張水田面積，在大嵙崁溪上游興建桃園大圳，其引水量之大造成中、下游水利組合的供水量大幅減少，尤其是位於大嵙崁溪最末端的後村圳所受影響最大；加上遭逢昭和3年（1928）以來連續兩年旱災，後村圳灌溉區的農民迫於生計，群起向總督府申訴，促使總督府在後村圳的圳尾地區興建抽水站以改善當地供水，但未能有效解決旱季缺水的問題。顯示日治中期以後，後村圳灌溉區的爭水事件已有所質變。受到自然環境（旱災及洪災）及人文環境（桃園大圳）的雙重壓迫，天災人禍 交加之下，後村圳內部的爭水事件從灌溉區內部的「圳頭、圳尾之爭」，轉變為與外部的上游大型水利設施的「上游、下游之爭」。另也反映出臺灣總督府以近代的法人組織改造清代的埤圳主一人獨斷式管理，並以近代工程技術整頓及維護水利系統，逐漸將灌溉區內的農民統合為一個整體，因此在面臨旱災及桃園大圳等自然及人為的雙重危機之際，得以消弭清代以來的宿怨，口徑一致對外與臺灣總督府極力扶植的官設埤圳進行抗爭。然而，臺灣總督府著眼於桃園大圳灌溉面積較之後村圳廣大數倍，因而採取犧牲下游地區的政策方針，殖民政府面對環境危機及少數人民抗爭時，棄車保帥的態度在此展露無遺。

This article aims to explore the historical transition of the dispute of water conservancy in the irrigated area of Hòu Cun Zùn（後村圳）, study the process and reason that the nature of water conservancy occurred transition. Hòu Cun Zùn is a water systems formed in the Japanese ruled period by Jhang Cuò Zùn（張厝圳） and Lióu Cuò Zùn（劉厝圳） drilled in the time of the Qing Dynasty ruled period. At the beginning of the drilling of Jhang Cuò Zùn and Lióu Cuò Zùn, a litigation occurred to fight for land of weir. Afterwards, because the water right was unclear and the watercourse was intermixed , disputes of water conservancy constantly appeared. Scrambling for water between headstream and downstream occurred frequently. In the Japanese ruled period, in order to develop the agriculture, the Taiwan Government（臺灣總督府） intervene the traditional operation of water conservancy with authority, form the public organization of water conservancy, and rebuild the facilities of acequia, the supply of irrigated water was assured. In the 1920s , in order to extend the square measure of rice paddy, the Taiwan Government build the Taoyuan Dà Zùn（桃園大圳） in the headstream of Dà Ke Kǎn Si（大嵙崁溪）. The overdrafting of the Taoyuan Dà Zùn make the supply of water of Hòu Cun Zùn a great quantity of decreasing. Besides, two dry seasons continued appearing since 1928, farmers in the irrigated area of Hòu Cun Zùn held together to accuse to the Taiwan Government. That forced the Taiwan Government build pumping stations to improve the water supply, but it still could not solve the lack of water in dry season. It reveals the dispute of water conservancy in the irrigated area of Hòu Cun Zùn had been made a qualitative change. Constricted by environment and man-made interference, the dispute of water conservancy in the irrigated area of Hòu Cun Zùn had changed from scrambling for water between headstream and downstream of Hòu Cun Zùn to between Hòu Cun Zùn and Taoyuan Dà Zùn. It also reflects that the Taiwan Government sacrifice the area of downstream with less square measure of rice paddy when it faced the environmental crisis.