Engineering: issues, challenges and opportunities for development ...

ENGINEERING FOR DEVELOPMENT: APPLICATIONS AND INFRASTRUCTURE■■■local management and financing;affordability; and,equitable services for all.One of the hardest lessons for the water supply and sanitationsector is that making the initial capital investment is oftenthe easiest part of the job. It is often relatively easy to find theresources (money, labour, materials and organization) for onebig push to build something. It is, however, much more difficultto maintain a truly sustainable system.The constraints identified as contributing to or causing the failureof water supply, and especially sanitation services, include:■■■■■■■■■■■■■poor organizational structures in the responsible agency;lack of spare parts;inappropriate technology;lack of trained staff;tied funding;an absence of career opportunities;insufficient funds;legal framework problems;lack of motivation by sector personnel;non-involvement of the users;the low profile of operation and maintenance in the sectorin general;inadequate tariff and collection systems; and,negative political interference.Global challengesCities all over the world are facing a range of dynamic globaland regional pressures, and difficulties in efficiently andtransparently managing ever-scarcer water resources, deliveringwater supply and sanitation services. There are equal challengeson disposing of wastewater and minimizing negativeimpacts to the environment. In order to develop solutions tomanage urban water more effectively, these global and regionalpressures must be recognized and used to drive the design andmanagement processes of urban water systems (Khatri andVairavamoorthy, 2007). 145■ Climate change is predicted to cause significant changes inprecipitation and temperature patterns, affecting the availabilityof water and the effectiveness and required capacityof sanitation infrastructure.■ Population growth and urbanization are enforcing rapidchanges leading to a dramatic increase in high-quality waterconsumption. Frequently, this demand for water cannotbe satisfied by the locally available water resources, whilethe discharge of insufficiently treated wastewater increasescosts for downstream users and has detrimental effects onthe aquatic systems.■ Existing infrastructure is ageing and deteriorating. It isa technological and financial challenge to maintain andupgrade it in such a way that quality water can continue tobe delivered to all sectors, and so wastewater can be adequatelycollected and treated.Climate changeThere is little dispute that the Earth system is undergoing veryrapid changes as a result of increased human activities. As aresult of these changes it is generally accepted that we havebegun to witness changes in the natural cycles at the globalscale. Clearly these changes will severely impact the urbanwater cycle and how we manage it. Components of the urbanwater cycle, like water supply, wastewater treatment, andurban drainage are generally planned for life spans over severaldecades. Hence there is a need for us to pay attention to thesechanges in the context of how these systems will be designedand operated in the ‘city of the future’.Although the regional distribution is uncertain, precipitationis expected to increase in higher latitudes, particularly in winter.This conclusion extends to the mid-latitudes in most ofthe General Circulation Model results. Potential evapotranspiration(ET) rises with air temperature. Consequently, evenin areas with increased precipitation, higher ET rates may leadto reduced runoff, implying a possible reduction in renewablewater supplies. More annual runoff caused by increasedprecipitation is likely in the high latitudes. In contrast, somelower latitude basins may experience large reductions in runoffand increased water shortages as a result of a combination ofincreased evaporation and decreased precipitation.The frequency and severity of droughts could also increase insome areas as a result of a decrease in total rainfall, more fre-145 Khatri, K., and Vairavamoorthy, K. 2007. Challenges for urban water supply and sanitationin the developing countries. Water for a changing world: Enhancing local knowledgeand capacity, (Symposium, 13–15 June), 50th anniversary, UNESCO-IHE Institutefor Water Education, Delft.© CCBY - Amit Dave - Reuters, Corbis Waiting at the water wellat Natwarghad, India.285