Shàn È 單鍔 (1031–1110), zì Jìyǐn 季隱, of Yíxìng 宜興 (Chángzhōu, Jiāngsū), was a Northern Sòng jìnshì of Jiāyòu 4 (1059) under the examination administration of Ōuyáng Xiū. Refusing to take official office, he devoted himself for over thirty years to the field study of the hydraulic system of the Wú region — Sūzhōu, Chángzhōu, and Húzhōu — riding alone in a small boat through every channel and creek to survey their sources and topography. His treatise, the Wúzhōng shuǐlì shū (KR2k0061), was submitted by his friend Sū Shì 蘇軾 to the throne in Yuányòu 6 (1091) but the proposal was suspended when Sū was impeached. His upstream-weir-closure thesis nevertheless was implemented in stages by Xià Yuánjí (Yǒnglè era) and Zhōu Chén (Zhèngtǒng era), and his work remained the foundational reference for the SòngYuánMíngQīng Tàihú-basin hydraulic debate.