Modelling of reservoir water quality under the effects of Climate Change
Coping with climate change impacts has become an important issue across the world, particularly in light of continuing urbanization and the high costs associated with damage. In the Singapore context, changes in rainfall patterns, sea level rise, increasing temperature and related impacts are relevant. This study aims to address the possible effects of climate and socio-economic changes on Singapore’s freshwater reservoirs over the next 100 years. The information will be valuable in providing the scientific basis required to support Singapore making well-informed decisions on future developments with a view to safeguarding our water resources.
Water quality monitoring and modelling
Management of inland surface water quality is of great importance worldwide due to potential issue of eutrophication. The lake system of Gardens by the Bay (GBTB) is located in one of the most urbanized catchments in Singapore, and it receives storm water runoff from the fertilized gardens. The lake water is discharged back to Marina Reservoir, which serves as a drinking water source and recreational water body. Public health is thus a consideration when managing water quality in GBTB. Besides, aesthetic values of the lake system are significant, as GBTB is a popular tourist attraction.
As part of a research-based assessment of the water quality in GBTB, continuous water quality monitoring was carried out; Trophic state of the lake system was evaluated; A simplified water quality model was built for reproduction of ecological responses to nutrient input in the lake system; Prevention and mitigation methods for eutrophication and sustainable development of the lake system was suggested.
Coral & Seagrass
Marine infrastructure development projects (involving dredging, reclamation and construction works) are crucial for safety and economic development of regions, harbours and industrial activities worldwide. In tropical regions, however, these development activities often take place in the vicinity of critical but sensitive marine ecosystems such as coral reefs and seagrass beds. Hence, this research project aimed to:
- Improve our understanding of the natural dynamics of critical marine ecosystems (coral reefs and seagrass beds) in tropical coastal waters in response to environmental variability in turbidity and sedimentation;
- Generate advanced knowledge about stress responses and resilience of critical marine ecosystems (coral reefs and seagrass beds) to turbidity and sedimentation in tropical coastal waters;
- Deepen our understanding of factors determining the success and scale of (post-impact) recovery of critical marine ecosystems (coral reefs and seagrass beds) in tropical coastal waters (including the role of recruitment).
Ecosystem Services by Mangroves
Mangroves provide critical ecosystem services (nutrient cycling, pollutant capture, carbon sequestration, fisheries and biodiversity) and can reduce coastal vulnerability by buffering wave energy. Intertidal vegetation has been used for coastal defence in Northwest Europe for more than 15 years under the names of managed realignment or depoldering, though its use holds much promise in Southeast Asia.
Utilising field measurements, remote sensing, flume studies and hydrodynamic modelling (Delft3D), this project quantified the effectiveness of mangroves for wave attenuation, and the critical thresholds that determine their survival in Singapore and Thailand. This will aid their use for sustainable coastal defence in Southeast Asia, and increase the success of future restoration efforts.
Large-scale Sediment Transport and Turbidity in Singapore’s Coastal Waters
Suspended particulate matter has been steadily increasing around Singapore due to extensive human interferences such as dredging, reclamation and fluvial inputs. Increased turbidity particularly threatens coastal ecosystems. This project identified a sediment budget for Singapore’s coastal waters to determine the processes responsible for this increase, including sediment sources and sinks.
The sediment budget is determined through a combination of satellite imagery (including maps of surface sediment concentration), ground-referencing (of flow velocities, fine sediment concentration and laboratory analysis) and numerical modeling (of transport of sand and fine particles due to tide-, wind-, density-driven currents and waves).
This structured analysis and quantification of sedimentation and erosion parameters provides a better understanding of the uncertainties surrounding sediment sources, distribution and budgets in Singapore coastal waters.
The demand for water is increasing worldwide. To ensure supply, water resource managers build reservoirs that are often connected to form complex multi-reservoir systems. Different users compete for the same water in the reservoirs and have different objectives, such as drinking water supply, flood protection, recreation and electricity generation. Reservoir systems are operated with the support of operational management tools. The presence of multiple and conflicting objectives and the uncertainty associated with the hydro-meteorological processes calls for novel hydro-informatics tools.
The ‘Multireservoir’ project developed tools for the most complex water systems, in order to support appropriate management decisions.
The Upper Peirce Research Program
The Upper Peirce Research Program aimed to improve understanding of hydrodynamic, chemical, biological, and biochemical processes in tropical reservoirs through experimental work, modelling and advanced and innovative monitoring. This research is focused on the Upper Peirce Reservoir due to its importance as a major drinking water resource for Singapore.
The Must Have Box (MHBox) project focuses on understanding the causes of residual, non-tidal sea levels and currents (anomalies) in the Singapore region and from the understanding to develop a potential maritime decision support system for various potential stakeholders.
The SDWA “Peatland Water, Carbon and Ecosystems Management Research Programme” aimed to support large-scale science-based implementation of improved water management and improved spatial planning of production and conservation areas in peatlands in Southeast Asia.
Punggol-Serangoon Reservoir Study
The Punggol-Serangoon Reservoir Scheme was developed by PUB in an ongoing effort to ensure long-term and sustainable water supply for Singapore. SDWA and Deltares developed an extensive modelling framework based on coupled rainfall-runoff, loading, hydrologic, hydraulic, hydrodynamic and water quality models. An innovative aspect of the modelling framework was application of the newly developed loads model to determine the pollutants from the catchment based on land use information.
Ecotoxicology and risk assessment of trace contaminants
The bioavailability of trace contaminants, i.e. the fraction of the pollutants which is available to organisms, is controlled by the water/sediment physico-chemistry, but also by hydrodynamics and biological processes. This fraction is now recognized as a critical parameter in understanding ecological processes, aquatic toxicity to pollutants, but also the effectiveness of various water pollution control technologies. We worked at measuring this fraction, using both real organisms (e.g. bivalves), and also innovative biomimetic techniques (e.g. passive samplers).
Real Options Analysis
Complex engineering systems are usually designed to last for many years. Such systems will face many uncertainties in the future. Hence the design and deployment of these systems should not be based on a single scenario, but should incorporate flexibility. Flexibility can be incorporated in system architectures in the form of options that can be exercised in the future when new information is available. Incorporating flexibility comes, however, at a cost. To evaluate if this cost is worth the investment a real options analysis can be carried out. This approach is demonstrated through analysis of a case study of a previously developed static system-of-systems for maritime domain protection in the Straits of Malacca.