Environmental Advances (Jul 2023)
Multi-criteria evaluation for long-term water resources augmentation planning with consideration of global change
Abstract
Rapid river basin urbanization inevitably results in drastic increase of water demand which necessitates the development of new water supply schemes to meet the sectorial water resource requirements. Various proposed water resources schemes will need to be evaluated and assessed and the optimum scheme selected for implementation. To prepare for capital budgeting, river basin managers need a set of comprehensive tools for objective decision-making to plan for the water works based on projected water demand due to population growth and water resources regime changes attributed to climate change. A multi-criteria analysis (MCA) approach has been developed for water resources planning with consideration of global changes to plan suitable schemes at various future years, using a set of technical evaluation tools, which comprise (i) water availability, (ii) system reserve capacity, (iii) climate resilience (iv) undeveloped (remaining) yield capacity and (iv) residual flow with respect to environmental flow. The indicators are based on a water resources index (WRI), defined as the ratio of the actual water resource availability (WRA) to the average water resources capacity (WRC) for a specified duration. The novel approach has been applied to Klang River basin in Malaysia, an example of a highly urbanized basin which is heavily dependent on inter-basin water resources. Water demand projection shows that the existing planned water works are inadequate beyond the medium time-horizon between the next five to ten years. There is thus an urgent need to attain water resource self-sufficiency for long-term sustainability. Proposed schemes are evaluated considering climate change up to year 2100. Analysis shows that Klang River basin can benefit from a coastal reservoir designed to intercept the basin river discharge for water resource development to reduce its dependence on inter-basin transfer from the adjacent Selangor River and Langat River basins which are under accelerated development and urbanization to avoid further water competition. The study is an outcome of the program entitled “National Water Balance System (NAWABS)” implemented by the Department of Irrigation and Drainage, Malaysia for basin-level water resource planning and operation towards drought preparedness.
