Traditionally, urban water managers have relied on large-scale, supply-side infrastructural projects to meet increased demands for water. This supply-side approach is under increasing pressure from a variety of mega-trends. To enhance urban water security, water managers are turning toward demand-side management.
Traditionally, urban water managers, faced with increasing demand for water alongside varying levels of supplies, have relied on large-scale, supply-side infrastructural projects, such as dams and reservoirs, to meet increased demands for water. This supply-side approach, however, is under increasing pressure from climate change, rapid population, and economic growth and even land-use changes impacting the availability of good quality water of sufficient quantities.
To enhance urban water security, water managers are turning towards demand-side management which aims to improve the provisions of existing water supplies before new supplies are developed. There are two types of policy tools available to achieve urban water security: fiscal tools and non-fiscal tools.
Fiscal tools to achieve urban water security
Fiscal tools include water pricing and the use of subsidies and rebates to modify water users’ behavior in a predictable, cost-effective way. Urban water managers typically price water using increasing block tariff rates, which contain different prices for two or more pre-specified quantities (blocks) of water with the price increasing with each successive block, or two-part tariff systems which contain a fixed charge and variable charge. Subsidies and rebates meanwhile are used to encourage water users to make sustainable consumption choices, for instance, subsidies are commonly used to encourage the uptake of water-saving devices and water-efficient appliances or technologies while rebates are commonly used to accelerate the replacement of old water-using fixtures and appliances. Overall, positive incentives are found to be more effective than disincentives in promoting water conservation.
New York City's On-Site Water Reuse Grant Pilot Program
New York City’s Department of Environmental Protection has launched its On-Site Water Reuse Grant Pilot Program to provide commercial, mixed-use, and multi-family residential property owners with incentives to install water reuse systems. Grants are available for water reuse systems at the individual building and district level, with district-scale projects involving two or more parcels of land such as a housing development, where the project reduces demand in the shared distribution system. Individual building-scale projects can receive up to $250,000 in reimbursement for a system designed to save at least 32,000 gallons per day (gpd), and district-scale projects are eligible to receive up to $500,000 in reimbursement for a system designed to save at least 94,000 gpd. The NYC Construction Code regulates two types of on-site water reuse systems that can be installed: wastewater reuse systems (black water, grey water, rainwater) for non-potable uses including flushing of toilets and urinals, laundry, and subsurface drip irrigation systems and rainwater reuse systems for non-potable uses including subsurface drip irrigation.
Non-fiscal tools to achieve urban water security
Urban water managers often rely on a range of non-fiscal tools to achieve urban water security including regulations as well as education and public awareness. Regulations often used include permanent and temporary ordinances that restrict certain types of water use during specified times and/or restrict the level of water use to a specific amount. Temporary and permanent ordinances are often used for a variety of purposes including restricting water levels during droughts as well as for ensuring new developments and renovations implement water-efficient fixtures and appliances. Meanwhile, education and public awareness are important to generate an understanding of water scarcity and create the acceptance of the need to implement water conservation programs.
Scottish Water's water and wastewater-related games
Scottish Water has developed three fun water and wastewater-related games as part of its Making It Clear program. The Pipeline Challenge lets players lay water supply and sewer pipes to complete a water and wastewater network as fast as they can. This fun, educational game takes users on a journey building the water supply and wastewater networks from the source to tap and then the wastewater back to the natural environment. The Clean It Up game lets users discover the treatment stages at a wastewater treatment plant with players taken through two key stages in a plant: the screening stage and the activated sludge stage. Finally, the Pumping Station game involves users controlling the water supply to all the people living in a block of flats with users experiencing the effort and energy required to supply clean tap water. As more people use the water, the more water needs supplying, but users will have to make sure they are not using too much energy in the process.
To achieve water security, urban water utilities can use a variety of fiscal and non-fiscal demand management tools to balance rising demand with limited and at times variable supplies.