Shan Pui River underwent engineering work by the government after the Yuen Long floods in the 1960s. The trunk and tributaries were turned into Yuen Long Nullah. The present design of Yuen Long Nullah is simple and monotonous. And the water flow is low, as if it was just a ditch. It can hardly fulfil the community’s expectations regarding the cityscape. Even worse, the channel is often full of rubbish, and stinks. Consequently, there is a strong public desire for environmental improvement. On the other hand, the damage channelisation wrought on the ecology and hydrology has long been criticised by environmental groups. They also demand that the government restore the channelised river.

River restoration aims to return the natural landscape and condition of the channelised river. River projects that damage the natural environment are being scrutinised in many countries, and river restoration efforts are underway. Building ecological riverbanks, reviving vegetation and biodiversity have become the trends in river projects around the world.

In January 2007, the Drainage Services Department commissioned a consultancy to conduct a feasibility study on the restoration of Yuen Long Nullah. According to the consultancy report completed in 2009, the current capacity of Yuen Long Nullah had to be maintained in order to cope with 1 in 50 year rainstorms. The consultancy report proposed that nullah’s original alignment, capacity, structural materials and shape be retained, and greening works should be implemented on the walls of the riverbank. Under this proposal, however, the meandering river and its natural landscape cannot be restored.

In view of the poor water quality, the consultancy suggested that water from upstream of Yuen Long New Town be intercepted, and a new channel could be installed to collect wastewater running into the nullah, and treated at Yuen Long Sewage Treatment Works. The consultancy also suggested that wastewater that had undertaken secondary treatment at Yuen Long Sewage Treatment Works be pumped back to the river upstream of Yuen Long New Town, so a stable and clean water flow could be maintained in the nullah all year round. However, this means building an interception facility additional to the inflatable dam downstream of Yuen Long New Town, which will further disturb the river’s hydrology. Furthermore, wastewater that has undergone secondary treatment still contains certain amounts of E. coli, and people should avoid direct contact with it. After a rainstorm, the water level of Yuen Long Nullah may rise a few metres within a short period. Due to safety concerns, people should keep out of the channel after restoration.

The natural Shan Pui River had multiple functions. After the river was channelised to become Yuen Long Nullah, only the single function of flood control remained. And other long-term problems arose. Therefore, there should be multiple aims, for avoiding future problems and fulfilling different needs of society. Based on the concept of river restoration, the original state and functions of Shan Pui River should be referred to as much as possible. Some of the functions, such as irrigation and navigation, may not need total revival; others such as water quality, landscape, ecology, recreation and microclimate regulation should be considered in restoring Shan Pui River, so the environmental impacts of the artificial channel can be minimised.


The present design of Yuen Long Nullah is simple and monotonous. And the water flow is low, as if it was a ditch.


The present design of Yuen Long Nullah is simple and monotonous. And the water flow is low, as if it was a ditch.


The water level in Yuen Long Nullah rises significantly and quickly after a rainstorm.


Water quality, landscape, ecology, recreation and microclimate regulation are some of the factors that should be considered in attempts to partly restore Shan Pui River.

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