During both the planning and the implementation phase constraints may arise. Suggestions for overcoming challenges is included in the following section.
10.2.1 Lack of data
The following best available data are needed to enable efficiency plans to be prepared:
• Demographic data (population and employment) and projections
• Monthly water production data
• The number of water accounts by customer class
• Monthly water sales (usage) data by customer class
• Planned changes to the water system (capital improvement projects, annexations, new planned customers or new water intensive industries that may change your future customers)
If certain types of data are not available or are inadequate then estimates must be used. Data gaps can be filled by using data from similar water utilities or research projects. Figures 10.1–10.3 shows how water is generally used in single-family homes in the Australia and the United States. Outdoor use (primarily for landscape irrigation) is highly variable and depends on rainfall and temperatures during the growing season. (Similar data from Australia are presented in Chapter 5).
If data of this type is not yet available, end uses could be estimated in the absence of local data based on estimate of litres per household per day and how effective various efficiency measures will be in reducing water use in existing and/or new homes. Breakdown of end uses presented in Figures 10.1–10.3 may help inform these estimates by illustrating the typical uses in the home in a developed country.
Table 10.2 presents World Health Organisation (WHO) requirements for level of service for domestic water use to meet human health and sanitation needs. Figure 10.4 illustrates the average per capita water use of listed countries.
Irrigation, 39%
Shower and bath, 25%
Toilet, 9%
Washing machine, 7%
Taps, 6%
Evaporative air conditioner, 4%
Leaks, 4%
Hand watering, 3%Pool & spa, 2%
Dishwasher, 1%
Figure 10.1 Average domestic end uses by area, Perth, Australia.Source: WSAA (2013).
Shower, 30%
Outdoor, 20%
Tap use/bath use/other, 19%
Clothes washer, 16%
Toilet, 14% Dishwasher, 1%
Figure 10.2 Average domestic end uses by area, Melbourne, Australia.Source: WSAA (2013).
Conservation, 86.7 lcd , 31%
Faucets, 40.9 lcd , 15%
Showers, 37.9 lcd , 14%
Clothes Washers, 40.1 lcd , 15%
Toilets, 36.3 lcd , 13%
Leaks, 18.9 lcd , 7%
Other Domestic, 5.7 lcd , 2%
Baths, 4.5 lcd , 2%
Dishwashers, 3.8 lcd , 1%
Typical Single Family Home Indoor Water Use With Conservaon
Toilets, 76.1 lcd , 28%
Clothes Washers, 57.2 lcd , 21%
Showers, 47.7 lcd , 17%
Faucets, 42 lcd , 15%
Leaks, 37.9 lcd , 14%
Other, 5.7 lcd , 2%
Baths, 4.5 lcd , 2%
Dishwashers, 3.8 lcd , 1%
Typical Single Family Home Indoor Water Use Without Conservaon
Figure 10.3 Average indoor end uses of water in single-family homes in the United States.Source: American Water Works Association (1999).
The Human Development Reports prepared by the United Nations Development Programme documents that some countries do not have adequate access to reliable water supplies for human health needs. The first goal of these countries is to extend service. Being more efficient with existing supplies, such as reducing non-revenue water, is part of the solution.
4151515151515272736364646 86 135149164173187193210 250 287301320 366374386 493 575
0 75 150 225 300 375 450 525 600
MozambiqueCambodiaRwandaEthiopiaUgandaAngloHaiti Burkina FasoBangladeshNigeriaGhanaKenyaChinaNigerIndia United KingdomUnited StatesPhillipinesGermanyDenmarkAustraliaNorwayAustriaFranceMexicoJapanSpainBrazilPeruItaly
Liters per Capita per Day (lcd)
Figure 10.4 Water use (litres) per capita per day in 2002 for listed countries. Source: United Nations Development Program (2006).
Table 10.2 Summary of requirement for water service level to promote heatlh.
Service level Access measure Needs met Level of
health
Consumption–cannot be assured Very Hygiene–not possible (unless high
practised at source)
Consumption–should be assured High Hygiene–hand washing and basic
food hygiene possible,
laundry/bathing difficult to assure unless carried out at source 100 m or 5 minutes total collection time)
Consumption–assured Low
Hygiene–all basic personal and food hygiene assured, laundry and
Consumption–all needs met Very low Hygiene–all needs should be met
Source: Howard and Bartram (2003).
10.2.2 Knowledge of efficiency measures
Water efficiency planners are often hampered by a general lack of knowledge about water-saving devices and measures. For more information on measures than the table of example measures presented in Appendix 3, good sources of information are the efficiency plans of agencies that have an efficiency programme as well as Internet sites of water supply utilities that are active in the efficiency field.
Guidebooks and manuals have been written on the topic and they can serve as a resource for those new to the field. Many new professionals start by accessing information from local and regional information networks. A wealth of information is available on the Alliance for Water Efficiency web site (http://
www.a4we.org). For a list of internet resources see Appendix 2.
10.2.3 Availability of long-range capital facility plans
Deferring or downsizing capital projects is a major source of potential benefits for the efficiency programme.
Unfortunately, the cost-benefit analysis is often hindered by the lack of long-term water supply capital facility plans (giving types of projects and cost estimates), and may be adversely affected if water use is reduced. Some government oversight agencies require that water supply plans list future capital facility projects, the schedule and cost estimates, and water efficiency programme measures be formulated to qualify for government financing.
If water use is growing and will exceed the capacity of supply sources and/or water treatment and distribution facilities, capital expansion projects will be needed. If the plans do not cover the normal efficiency planning period (usually 20 years), the costs of these unplanned facilities should be estimated.
Supply projects are normally designed to provide for growth over a 10- to 20-year period. Similarly, expansion of water treatment projects is designed for growth over approximately 10 years, for which the cost of the facilities can be estimated. For example, water treatment plants in the United States cost between US$1 million and US$2 million for a capacity of 3875 m3per day.