Perhaps you’ve never considered the unsung heroes of flood prevention. Today we will visit one of these heroes. We are standing in front of the Ho Chung Lowland Pumping Station. This station plays a vital role in managing water levels. It helps protect the surrounding areas from flooding.
The story of Ho Chung River and this pumping station is intertwined with Sai Kung’s development. Rapid development increased surface runoff. The original Ho Chung River couldn’t handle the increased water flow. This resulted in a need to improve drainage and reduce flood risks.
In 2007, the Drainage Services Department or DSD began a project to improve the Ho Chung River. The project finished in 2009. The DSD widened the river channel. This was done by moving back the southern river bank. This widening significantly reduces flood risks.
But that is not all. The DSD incorporated new ecological conservation features. These features enrich the aquatic and riparian environment. These enhancements promote the river’s ecology. The overall cost of the project was about $160 million HKD.
Let’s delve into some of the ecological measures implemented. The river walls have holes called in-stream refugia. These holes provide refuge for fishes and invertebrates. They offer protection during high flow times. These refugia come in different forms. Some are isolated. Others are sets of interconnected holes.
Another interesting feature is the fish ladder. The original design was a concrete ramp. It had stones to help fish cross a Fung Shui weir. To improve its ecological utility, the design was changed. Now, it features randomly placed cobbles and boulders. This creates ripples and pools. This simulates a natural stream flow. The fish ladder allows fish and migratory invertebrates to pass. One example is the mitten crab.
Deflectors are lines of rocks placed along the riverbed. They vary in length. They induce variations in flow direction and velocity. This creates zones of different water depth. This creates diverse micro-habitats for various species.
During the widening of the Ho Chung River, large rocks were found. Instead of removing them, they were left in place. These rocks serve as resting places for turtles and birds.
Natural substrates were used in the widened part of the riverbed. This maintains the natural benthic habitat. It also enhances the river’s ecological value. The widened part covers about 7,750 square meters.
Interestingly, the Ho Chung area has significant archaeological history. A rescue excavation in 1999 unearthed remains from three cultural phases. These phases include Late Neolithic, Tang and Song dynasties, and Ming and Qing dynasties. The Ho Chung Archaeological Site is located on the southern bank of the Ho Chung River.
The excavation revealed a Neolithic workshop. It was used for manufacturing stone tools. This discovery provides valuable insights into the prehistoric people of Hong Kong. Artefacts from the Tang and Song dynasties suggest an ancient pier existed here. Porcelain sherds from various kilns across the country were found.
The Ho Chung Lowland Pumping Station and the improved Ho Chung River represent a blend of engineering and ecological awareness. The project protects the community from floods. It also enhances the natural environment. Next time you see a seemingly ordinary pumping station, remember the vital role it plays. Remember the thought and effort that goes into protecting our communities and preserving our natural heritage.