Hai Kou He river management

Hai Kou He river is the main draining river from Dain Chi lake to the upper basin of the Yangtze River. In the thirteenth century before it was dredged it was a small river, but even so the local people understood that it was the main drag for drainage of Dian Chi lake（Feng sixteenth century）. Therefore, hydraulic engineering for dredging the river was regarded after Kunming City was established as the capital of Yunnan province in Yuan Dynasty.

The earliest event to governing the Hai Kou He river was recorded by the document in 1273, Yuan Dynasty（Yuan History 1956）. According to the document, Mr. Zhang Li Dao, the agricultural administrator of Provincial Government of Yunnan, forced 2000 labourers to dredge and extend the Hai Kou He river. The idea of water governing from Da Yu（the first emperor of China in history, he was became to be the emperor due to successful water management）was adopted by Mr. Zhang Li Dao in implementing of engineering, what to do was to leading more water into the river but not follows the convention to making more and more mounds around the living areas to stop flood. Based on this, the river was dredged more deeply and broadly, accumulated soil in the river was moved and a new riverbank was built that enlarged Hai Kou He river to a width of 20m and a length of 10km after three years. After this project, drainage was effectively improved in the river that brought a decline of the water level in the lake from 1890m（a. s. l.）in the twelfth century to 1888.5m, the size of the lake was also diminished to 410km2 from 510.1km2, thousands of hectares of cultivable land were formed as a result of this change（Dian Chi Hydraulic Engineering-Graphy 1996）.