As we met Dr. Coffman and started our exploration of the Kallang River with my NUS GE3255 project group, it seemed as if we were seeing the past and the present at the same time.

The restored river was slowly flowing into the surviving remnants of its channelized past.

   

Figure 1: The restored stretch. (Photo Credit: my groupmate Teo Ying Qi)|

Figure 2: The surviving remnants of the river’s channelized past. (Photo Credit: Teo Ying Qi)

Shock – the emotion I had upon realizing that the beautiful curves of the river that I saw had been so brutally tortured to fit into the thin concretized channel that flowed (figures 1 and 2). A 2.7 km long straight concrete channel was what the Kallang River used to be at the Bishan-Ang Mo Kio Park (BAMK). In the 1970s, canals and drains were built to alleviate flooding in various parts of Singapore. The aim was to rapidly convey the rainwater runoff as well as the polluted waters from one point to the other (in this case mainly the ocean). But with increasing precipitation and urbanisation, the Kallang River canal needed more capacity than it had. This led to the restoration of the river into its naturalized state in BAMK park. Under the Public Utilities Board’s (PUB) flagship project Active, Beautiful and Clean Waters (ABC) programme in 2010-12, the canal was transformed into its current self that runs through a 3.2 km long meandering channel.

The concrete slabs of the canal were removed and stacked up to create Recycle Hill. And a series of soil bioengineering techniques and earth control measures were implemented along the river’s stretch to prevent soil erosion and stabilize the stream banks. About ten bioengineering techniques were tested out at BAMK before seven were finally applied along the river. We found many gabions, riprap, and bioretention swales (bioswale) while exploring the river.

Figure 3: The gabions we observed on the field trip. (Photo Credit: my groupmate Ruan Xinpei)

BAMK park is now a habitat for a wide range of species of birds, dragonflies, wildflowers, and other aquatic and riparian flora, and fauna. The Kallang River hosts Singapore’s notable otters (we were lucky enough to see them during our field visit). It also provides leisure and recreational opportunities to the communities located around BAMK park, but for all Singaporeans since it is centrally located.

Figure 4: The otters we spotted during our field trip. (Photo Credit: my groupmate Yeo Bin Jie, Benjamin)

Studying this restoration and its impacts on hydrogeology, biodiversity, and ecosystems made me appreciate the restoration efforts that were involved in bringing this river to life again!