Lee Kong Chian Natural History Museum

Freshwater Biomonitoring


‘Biological monitoring’ or ‘Biomonitoring’ of freshwaters is the use of aquatic organisms to detect change, often due to pollution, in rivers and lakes. Fish, algae and benthic invertebrates can be used as ‘bioindicators’ of pollution or disturbance because they demonstrate differential sensitivities to pollution. However, because community level information is complex and requires expert interpretation, Biotic indices of water quality and ecological condition are developed as compound metrics of condition for ease of interpretation for operational management of these systems and communication to the public.

Benthic (bottom-dwelling) invertebrates are most commonly used in the assessment stream health worldwide and are being increasingly adopted for standing waters (Rosenberg and Resh, 1993). These animals are without an internal skeleton and visible with the naked eye. They include insect larvae, snails, shrimps, and various worms that live almost entirely in the sediments at the bottom of lakes and streams. Some worms and midge larvae are able to tolerate relatively polluted waters whilst others, such as mayflies and stoneflies are sensitive to pollution. Their presence and/or abundance, weighted by their sensitivity to pollution is used to calculate biotic indices of water quality and ecological health. Because the presence of different invertebrates in the sediments is indicative of the conditions of the freshwater system throughout their aquatic life-span, the use of these indices in a comprehensive monitoring programme effectively complements periodic chemical point-sampling which may miss ‘one-off’ or rare pollution events.

Freshwater Biomonitoring in Singapore
A biotic index for reservoir water quality and one for stream health were developed using benthic macroinvertebrates in collaboration between local and international universities and the Public Utilities Board (PUB), Singapore. The BQISING index of tropical reservoir water quality is developed by the National University of Singapore (NUS)(Clews et al., 2009; Loke et al., 2010) and concurrently, the University of Canterbury, New Zealand developed the SingScore index of waterway health in Singapore (Blakely and Harding, 2010).

These biotic are now being applied in Singapore under the ‘Long-term Bio-index Project’ undertaken by the Freshwater Section of the Ecological Monitoring Informatics and Dynamics (EMID) group at the Tropical Marine Science Institute (TMSI), NUS with support and funding from the PUB. The EMID group specialises in ecological monitoring and assessment of aquatic systems whilst the Catchment and Waterways department of the PUB is responsible for the management of Singapore’s ‘raw’ waters. Biomonitoring work is undertaken under a National Parks Board research permit.

In Singapore, the operational use of biotic indices in a national biomonitoring programme to detect pollution began in October 2011. This programme now serves as additional surveillance monitoring to complement the water quality and algal sampling which is routinely conducted by the PUB. This programme tracks changes in environmental and water quality to ensure that Singapore’s waters are healthy. Such information can then contribute towards management decisions for the development of pollution control measures and best management practices, and also provide a means to test the effectiveness of these strategies in mitigating and minimising pollution. In Singapore, the Active, Beautiful, Clean (ABC) Waters Programme aims to improve flood control, water quality and to enhance biodiversity through in-stream, bank-side and wetland design features (PUB, 2011). Routine assessment and evaluation of rehabilitation projects through biomonitoring improves our understanding of freshwater ecosystems in Singapore. This will help us to effectively create new habitats, reduce pollution and enhance biodiversity in Singapore.


Blakely, T. J. & J. S. Harding, 2010. The SingScore: A Macroinvertebrate Biotic Index For Assessing The Health Of Singapore’s Streams And Canals. Freshwater Ecology Research Group, Research Report, University of Canterbury, New Zealand.

Clews, E., E. Low, C. Belle, L. Loke, P. Todd, H. Eikaas, & P. Ng, 2010. A Pilot Biotic Index For Reservoir Water Auality Assessment. National University of Singapore and the Public Utilities Board, Singapore.

Clews, E., & A. D. Tran,  2010. Jacks of all trades. Pp. 106–125. In Yeo, D. C. J., L. K. Wang, & K. K. P. Lim (editors), Private Lives: An Exposé of Singapore’s Freshwaters. Raffles Museum of Biodiversity Research, Singapore. pp 258.

Loke, L. H. L., E. Clews, E. Low, C. C. Belle, P. A.Todd, H.S. Eikaas & P. K. L. Ng, 2010. Methods for sampling benthic macroinvertebrates in tropical lentic systems. Aquatic Biology 10: 119–130.

Metcalfe-Smith, J. L., 1996. Biological water-quality assessment of rivers:use of macroinvertebrate communities. In Petts, G. and Calow, P. (editors.), River Restoration pp 17–43. Blackwell, Oxford.

Morse, J. C., Y. J. Bae, G. Munkhjargal, N. Sangpradub, K. Tanida, T. S. Vshivkova, B. Wang, L. Yang & C. M. Yule, 2007. Freshwater Biomonitoring with Macroinvertebrates in East Asia. Frontiers. Ecology and the Environment 5 1 33–42.

Ng, P. K. L., R. T. Corlett & H. T. W. Tan (editors), 2011. Singapore Biodiversity. An Encyclopedia of the Natural Environment and Sustainable Development, Editions Didier Millet, Singapore, 552 pp.

PUB (Public Utilities Board), 2011. Active, Beautiful, Clean Waters Design Guidelines. PUB, Singapore.

Rosenberg, D. M. & V. H. Resh, (editors.), 1993 .Freshwater Biomonitoring and Benthic Macroinvertebrates. Chapman and Hall: New York, NY, USA.

Tang H. B., L. K. Wang & M. Hämäläinen, 2010. A Photographic Guide To The Dragonflies Of Singapore. Raffles Museum of Biodiversity Research, National University of Singapore. 222 pp.

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