Lushui ketan 潞水客談

Lushui ketan 潞水客談 "Guest talks of River Lu", also called Xibei shuili yi 西北水利議, is a book on water conservation written during the late Ming period 明 (1368-1644) by Xu Zhenming 徐貞明 (d. 1590), courtesy name Rudong 孺東, from Guixi 貴溪, Jiangxi. He was once the district magistrate of Shanyin 山陰, and his highest office was Vice Directorate for Palace Delicacies (shangbao xiaoqing 尚寶少卿). Xu was known for his expertise of hydrology of the capital region.

The book of 1 juan was written after the author personally travelled through the various prefectures and counties of the capital region, conducting a thorough survey of the sources and courses of the rivers and springs there. It was completed during the reigns of the Longqing 隆慶 (1567-1572) and Wanli 萬曆 (1573-1619) emperors, and contains about seven thousand characters.

The work takes the form of dialogues between a guest (ke 客) and Xu Zhenming, through which the author shares his views. It discusses extensively the advantages and disadvantages of various water management methods, advocating the construction of sluices and dams along rivers such as the Hutuo 滹沱 and Zhang Rivers 漳河, and the transformation of dry fields into paddy fields. These measures, he argues, would ease the burden of transporting grain from the south to the north, reduce the cost of grain tribute, and lessen the corvée labour and taxes imposed on the southern regions.

The discussion includes an exposition on the importance and feasibility of agricultural irrigation in the capital area. The book provides a detailed analysis of fourteen benefits of developing water conservancy projects there, as well as the difficulties and challenges that might arise in carrying out such large-scale hydraulic works. It sets forth the principles for eliminating water disasters and developing irrigation in the capital region—namely, unified planning combined with section-by-section management and also proposes plans and steps to change the system of transporting grain from the south to the north. The book emphasizes that "when water is concentrated, it causes harm; when it is dispersed, it brings benefit". Accordingly, it advocates building irrigation channels in the upper reaches of the Hai River 海河, opening distributary channels in the lower reaches to divert floodwaters, retaining low-lying lakes and marshes for water storage, and reclaiming the surrounding wetlands into polders for cultivation.

Based on the different conditions of each river system, the author thus suggests suitable methods of governance. His ideas later played a significant role during the Yongzheng reign-era 雍正 (1723-1735) of the Qing period 清 (1644-1911), when In Siyang (Ch. Yinxian 胤祥, 1686-1730), Prince Yixian 怡賢親王, initiated major projects to manage the waterways and develop irrigated fields near the capital.

The text is found in the series Jifu hedao shuili congshu 畿輔河道水利叢書. It is also integrated into Xu Guangqi's 徐光啟 (1562-1633) Nongzheng quanshu 農政全書 and the compendium Ming jingshi wenbian 明經世文編.