Transformation of the Kai Tak River | News on the Kai Tak River
 

Kai Tai River, commonly known as the Kai Tak Nullah, with a length of 1.5km, is the waterway situated between Kowloon City and San Po Kong. Historically called ‘Long Jin River’, Kai Tak Nullah was constructed in the course of airport expansion during the Japanese occupancy in 1940s. It connects both historically and geographically urban housing settlements and monuments of a few generations, like Wong Tai Sin Temple, Tai Hom Village, Morse Park, Nga Tsin Wai Walled Village, and Tung Tau Estate. The open nullah is a channel collecting the natural rainfalls, with its catchment areas covering a few Eastern Kowloon districts, like San Po Kong, Diamond Hill, Chi Wan Shan, Wong Tai Sin and Kowloon City. Within such a rich context, it also witnessed the urban transformation of Kowloon Peninsula, through stages including rapid urbanization, turned into a nullah during the WWII and eventually polluted by untamed sewage discharges from factories in the vicinity.
In the 60s and 70s, due to reasons of illegal pollutant discharges from factories, untamed domestic sewage from squatter huts, and mistaken connections of surface waters in the vicinity, etc., the open Kai Tak Nullah was seriously polluted, thus released unpleasant smells. Although relevant authorities had been cleansing the nullah from time to time, the improvement was hardly noticeable such that the dilapidated environment and the smells continues to bother the local residents. In 1986, the Environmental Protection Department (EPD) started to monitor the water quality of the rivers in Hong Kong systematically and up to the mid-90s, the water quality of the Kai Tak Nullah was still graded as ‘poor’ or ‘extremely poor’, which reflects the degree of pollution. In order to resolve the pollution problem, the EPD has begun to take fundamental measures from the 90s, starting projects like the sewage collection project in Eastern Kowloon, and the construction of water gate to prevent reverse flows of polluted rainwater in dry seasons. At the same time, the government also demolished squatter huts around the catchments reducing the volume of untreated sewage discharge into the nullah. In 1995, the Tolo Harbour Effluent Export Scheme began piping the treated effluent from the Sha Tin and Tai Po Sewage Treatment Works to the Kai Tak Nullah. In this way, the flow volume of the nullah increased and improved the water quality along the whole waterway.

In 2001, the Drainage Services Department (DSD) began to deal with the illegal sewage discharges, discovered more than 90 mistaken connections and rectified over 90% of them. The next year, the authority also constructed the concealed pipe for the dry-season sewage drainage, further reduced the unpleasant smells. In 2004, the government completed the Kai Tak Transfer Scheme by diverting the rainfalls from Central Kowloon via the Kai Tak Nullah to the sea. It not only has drastically reduced the risk of flooding in the Central Kowloon, it also increased the flow along the nullah, thus recovering its function of flood prevention. Since 2005, the water quality of the Kai Tak Nullah has improved and the water quality indices from the six monitoring stations graded the water quality in the Kai Tak Nullah as ‘good’ or ‘excellent’. Since then, the downstream of the nullah became a natural habitat that attracts fishes and birds.

With the improvement of drainage works in recent years, the Kai Tak Nullah gradually resumes its water quality as in the past. In Sep 2007, the nullah was renamed publicly as the “Kai Tak River” – the process of rediscovering a lost human landscape towards a social sustainability began.