夏原吉在永樂元年到三年之間受命到江南治水。本文所關注的課題，是此一派任與夏原吉的治水作為，和永樂皇帝推翻建文皇帝之後亟欲確立其政權正當性的期望兩者之間的關係。通過考察夏原吉的派令、其治水措施之抉擇、其中牽涉的聖君論述，以及永樂皇帝對治水的態度及其轉變，本文發現這些行動與論述有著建立永樂政權正當性的斧鑿痕跡。此外，夏原吉的治水論述與具體作為，強調以「三江」來提綱挈領地整治當地水系，這和宋元以來治水江南者的實際作為之主流是相悖的，何以如此？本文將以永樂皇帝初上任時的歷史情境為基礎，提供一個初步的解釋：政治上的實際需求(永樂皇帝的期待與夏原吉在新朝建功之壓力)，與「三江」所承載的文化意義，以及當時既存的環境條件(此乃前代人力與自然相互作用之後的結果)相互作用，凝鑄成夏原吉深具歷史特殊性的抉擇。藉著本文的討論，筆者也提出研究取徑上的反省：除了環境的變遷以及水利的實際措施之外，水利史的研究似乎尚可將具體情境中的政治期待、文化意涵，與環境本有之條件所提供的可能性與限制性合併起來考量，以期在歷史的縱切面與橫切面上有更多層次的剖析。

Xia Yuanji (1366-1430) was appointed by the Yongle Emperor to take charge of water management in the Lower Yangzi Delta from 1403 to 1405. As is well known, the Yongle emperor ascended the throne by usurpation in 1402, and this article explores the relationship between Xia’s water management and efforts to establish the legitimacy of the Yongle administration. It is contended here that Xia’s appointment, his discourse on the sage-kings, and his choice of hydraulic strategies—as well as Yongle’s attitude toward water management—were closely related and directed at bolstering Yongle’s legitimacy. Taking inspiration from the theory of political ecology, I analyze the “Three Rivers” discourse formulated by Xia Yuanji from a political perspective. I argue that this discourse served to undergird Xia’s approach to water management because it implied that Yongle was a sage-king in the mold of the Great Yu, who was of course highly admired for his benevolence toward the people. The “Three Rivers” discourse also provided a clear description of the waterway system in the Lower Yangzi and laid out an effective way of taking advantage of the work done by Xia’s predecessors in the Yuan dynasty. Through an analysis of Xia’s approach to water management, this article also intends to offer a reflection on current research methodology. While existing literature on water management mostly focuses on environmental changes and concrete hydraulic policy, this article proposes that it is also important to pay due attention to historical actors’ political expectations and to the cultural implications of certain discourses in order to obtain a better understanding of the significance and consequences of a particular policy. Viewing hydraulic issues from this angle, this article maintains that water management is often more appropriately understood as an action directed at a political purpose, and not simply a response to a natural catastrophe.

夏原吉；永樂皇帝；治水；江南；正當性；三江

Xia Yuanji; Yongle Emperor; water management; Lower Yangzi Delta; legitimacy; Three Rivers