2 Description of the Project

2.1 Location and Nature of Project

2.1.1 Most of the watercourses in Mui Wo remain untouched at their upper reaches and are partially channelised at their downstream ends near River Silver. Pak Ngan Heung River, Luk Tei Tong River and Tai Tei Tong River merge at Silver River before passing Mui Wo township to Silver Mine Bay. The Luk Tei Tong (2) River is a tributary of Luk Tei Tong River and flows through an existing floodplain to the north of the Luk Tei Tong Village.

2.1.2 The drainage improvement works of the Project comprise the following:

· Construction of approximately 80m long gabion with natural bed at the upstream of the Pak Ngan Heung River, approximately 180m of three cells 3m x 2m diversion box culvert and approximately 100m of rectangular channel at downstream of the Pak Ngan Heung River;

· Construction of approximately 200m of 0.75m wide U-Channel at Ling Tsui Tau Village in Mui Wo;

· Construction of approximately 350m and 240m long of gabion channels at Luk Tei Tong By-pass Channel and Luk Tei Tong River respectively; and .

· Widening three existing bottlenecks with gabion lined at Tai Tei Tong River.

2.1.3 The general layout plans for the above drainage improvement works are shown in Figures 2.1 to 2.3. Alternative drainage improvement methods, channel alignments and designs had been considered in order to identify a practical, cost-effective and environmentally friendly scheme, with features including:

Pak Ngan Heung River, Tai Tei Tong River and Luk Tei Tong River

· Channel beds constructed using natural materials such as small cobbles and boulders to provide suitable environment for many organisms dependent on the existing watercourses. The existing river bed would not be touched as far as possible.

· Channel slopes lined with gabion.

· Depth of the channels varied to re-create the pool-riffle sequence found in natural streams.

· Larger pools in the stream and river currently maintained for crop irrigation would be re-instated.

Luk Tei Tong By-pass Channel

· The existing Luk Tei Tong (2) River would not be affected.

· To avoid affecting the ground water table in the adjacent marsh, a shallow and wide section of by-pass channel would be constructed, with bed lined with natural materials and banks lined with rock-filled gabion.

· The remainder of the Luk Tei Tong By-pass Channel bed would be designed as compensatory marshland habitat.

2.2 Works Programme

2.2.1 The drainage improvement works would commence in June 2006 and is expected to complete by June 2009.