Shan Pui River and Kam Tin River have undergone major drainage works during the Yuen Long New Town Development in the 1970s. The drainage works have not only improved the flood prevention capacities of the two rivers but also changed the environment and ecology in the vicinity.
To promote the functions and values of major rivers and to enhance the public awareness on conservation of Hong Kong rivers, Drainage Services Department has designated this trail as "Nam Sang Wai River Education Trail".
The Nam Sang Wai River Education Trail starts at Castle Peak Road in Yuen Long, goes around Nam Sang Wai via the Yuen Long Bypass Floodway, new channel of Kam Tin River and Shan Pui River. The Trail is about 5.5 kilometres long and takes 2 hours to complete. There are 10 Exhibition Panels along the trail to provide information on river training works and ecological aspects of the rivers.