District-scale water management: impacts on infrastructure, energy, pollution and greenhouse gas emissions

This paper explores the impact of water conservation and rainwater harvesting practices implemented at the site or district scale on the infrastructure, energy and water cycles of their larger urban systems. A case study is presented of a conceptual development in a Southeast Asian climate. Two technologies are examined: water-efficient fixtures and appliances and rainwater harvesting and beneficial use. Practices to reduce water consumption at the site or district scale have implications in the larger system, ranging from reductions in water that has to be treated and distributed, reductions in wastewater that has to be collected and treated, and reductions in energy consumed. Similarly, using rainwater for irrigation will reduce the amount of potable water demand, and will have system energy implications. The paper considers performance criteria for the entire water-energy system, including peak runoff, pollutant loads, energy and carbon footprints.