SWITCH Training Kit: Pilot Training, Entebbe, 28-29 July 2010

Water Demand Management in the City of the Future

The concept of water demand management and the benefits this can bring

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Demand Management

The development and implementation of strategies, policies, measures or other initiatives aimed at influencing demand, so as to achieve efficient and sustainable use of the scarce water resource

(Savenije and van der Zaag, 2002).

Any action that modifies the level and/or timing of demand for a particular resource

(White and Fane, 2001).

The looming water scarcity (1) World population to raise from 6.7 billion in mid-2007

to > 9.2 billion by 2050 There are finite global water resources Increased pollution rates Growing demand due to

o Increased populationo Increased affluence and industrial activities

Impact of climate change:o e.g. 2° temp raise ~ shortage for 1-4 billion people in

developing countrieso Increase in hydrological extremes

Per capita water availability steadily decreasing

Projected water & food scarcity in 2025

2b people (25%) will have absolute water scarcity

2.7b people (33%) will need to develop their water resources by 25%

Source: http://www.iwmi.cgiar.org/home/wsmap.htm#A1

The looming water scarcity (2)

By 2050, ~ 1/3 of pop in low-income countries will face severe shortage

Water scarcity more critical in urban areas, where >50% of global pop live (since 2007)

o 2000 – 2030, pop increase of 2.12 bn for urbano 95% of this increase in low-income countries

There is need for a paradigm shift in the way urban water services are managed, to prevent demand exceeding supply

Integrated Resource Planning (IRP)

Planning to meet multiple objectives at optimum costs

Customers do not demand for a resource but for a service, i.e. end-uses, rather than water itself

IRP – a systematic & participatory planning process to evaluate least cost analyses of both demand-side & supply side options

IRP considers both supply and demand options For sustainable UWM, utility managers need to

adopt WDM, which has been neglected in the past

WDM within the IRP framework WDM is the promotion of policies & measures that

serve to control/restrict demand for, use or waste of water supply/other water services

WDM then become integrated vertically, at o Policy levelo Utility levelo Consumer level

…. horizontally, in terms of o Technological interventions o Economic interventions o Social/educational/legislative interventions

….and strategically, in terms of time projections

DM measures include those aimed ato Increasing system efficiency at utility level, e.g.

Reduction in systems losses

o Increasing end-use efficiency, e.g. Domestic water efficiency measures, Public education

o Promoting locally & unused available resources, e.g. Rainwater Harvesting, Greywater reuse

o Promoting substitution of resource use, e.g. Waterless toilets, Greywater reuse

o Using economic instruments to promote efficient use of water Flexible water tariffs

(adapted from White & Fane, 2001)

Demand Management

Domestic Water Use

Rainwater harvesting and greywater reuse

Demand management in Entebbe - 1

Which water demand management measures have been used in Entebbe?

o Increasing system efficiency at utility level, e.g. Reduction in systems losses

o Increasing end-use efficiency, e.g. Domestic water efficiency measures, Public education

o Promoting locally & unused available resources, e.g. Rainwater Harvesting, Greywater reuse

o Promoting substitution of resource use, e.g. Waterless toilets, Greywater reuse

o Using economic instruments to promote efficient use of water Flexible water tariffs

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Demand management in Entebbe - 2

Which water demand management measures could be considered?

o Increasing system efficiency at utility level, e.g. Reduction in systems losses

o Increasing end-use efficiency, e.g. Domestic water efficiency measures, Public education

o Promoting locally & unused available resources, e.g. Rainwater Harvesting, Greywater reuse

o Promoting substitution of resource use, e.g. Waterless toilets, Greywater reuse

o Using economic instruments to promote efficient use of water Flexible water tariffs

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Assessing Supply and Demand Options

Economic benefits

Demand management measures o Save water consumed (volume in Ml)

Reducing the volumes treated and distributed Reducing the volumes of wastewater

o Save the cost of abstracting, treating and distributing the saved water

o Save the cost of collecting, treating and disposing of wastewater

o Delay / reduce capital expenditure required for enhancing water supply

o Reduced water loss improves the financial performance of the water service provider

Environmental benefits

Reduced consumption of watero Saving limited water resources

Reduced wastewater flows Reduced damage from leakage flows Reduced consumption of energy

o Saving limited resources of fossil fuelso Reducing emissions of greenhouse gases,

and thereby mitigating climate change

Social benefits Increased access to water supplies

o Reduced consumption by some users makes water available for others

o E.g. Transfer from high volume consumers to consumers with intermittent supplies

Improving hygiene and health Improving school attendance and performance Improving productivity and incomes

Increased social benefit from watero Transfer of water from uses with low social value to uses with

higher social valueo E.g. From leakage / waste to billed consumptiono e.g. From garden watering to bathing

Who Benefits from WDM? Customers who receive improved water supplies

o New customerso Existing customers

Customers who reduce their consumption, who get lower bills

The water service provider, from reducing losses, thereby increasing billed water volume and revenue

Future generations, from reduced depletion of resources, reduced carbon emissions and reduced pollution

WDM in municipality / health premises Educational campaigns for behavioural change Consider ways to improve water efficiency and water

conservation Investigate leakages within properties Influence building by-laws for installation of water-

efficient devices in the new buildings Work with the Trade/Commerce bureaus of standards

to regulate for water-efficient devices Carry out public sensitisation on WDM, starting with

schools

Acknowledgements

Sam Kayaga, WEDC Stuart White and Andrea Turner, ISF