Cover Image
close this bookEnvironmental Handbook Volume I: Introduction, Cross-sectoral Planning, Infrastructure (GTZ, 1995, 591 p.)
close this folderInfrastructure
close this folder10. Urban water supply
View the document1. Scope
View the document2. Environmental impacts and protective measures
View the document3. Notes on the analysis and evaluation of environmental impacts
View the document4. Interaction with other sectors
View the document5. Summary assessment of environmental relevance
View the document6. References

5. Summary assessment of environmental relevance

Generally speaking, it will not be possible to assess the severity of the impacts created by urban water supply systems by following a standard, fixed procedure and it will be more a matter of weighing the good intention of developing a life-preserving resource against the related consequences of interfering with the ecological equilibrium that will follow under the laws of nature. Those responsible for the project also need to be aware of the fact that drinking water performs the role of a pacemaker, in the widest sense of the word, for sociocultural and socioeconomic conditions and care therefore needs to be exercised in bringing it into play as a contributory factor to structural improvement.

An assessment of the environmental relevance of urban water supply can be undertaken by considering the following questions:

- the appraised water resources, and multi-sectoral use,

- evidence for efficient water use in present and planned urban water supply systems combined with efficient disposal,

- planning considerations of significance for environment-orientated urban water supply projects.


5.1 Appraised water resources, and multi-sectoral use

- Evaluation of the current availability and quality of water resources in the light of multi-sectoral use and seasonal variations in availability, quality and use.

- Reliable appraisal of the future availability and quality of water resources and reliable monitoring of their present availability and quality (constant measurement, hydrogeological, hydrological, chemical, physical and biological checks, and professional analyses and appraisals).


5.2 Evidence for efficient water use in existing or planned urban water supply systems coupled with efficient disposal

- Constant monitoring of the use of water resources by the body operating the urban water supply system in collaboration with other water resource users.

- Consumption monitoring, control of consumption (during dry periods), monitoring of water losses, and quality monitoring of the water supplied from the urban water supply system.

- Evidence of the need for rehabilitation work to be done on the urban water supply system, and particularly on the water distribution system, classified by priority.

- Efficient implementation of statutory codes and regulations,

- Efficient disposal and disposal monitoring,

- Effective provisions for improving the availability of water resources by means of artificial infiltration, retention basins, dams.

- Efficient re-use of cleaned water.


5.3 Curative measures for inefficient water use in existing urban water supply schemes and inefficient disposal

Curative measures may need to be applied to one or more of the items listed in 5.2

5.4 Important planning considerations for environment-orientated urban water supply projects

There is no fundamental reason why urban water supply systems should not be planned and constructed in an environment-orientated way. However, for this to be the case, there are a number of preconditions that have to be met which, in particular cases, may sometimes entail severe restrictions on water consumption.

The planning of environment-orientated urban water supply projects will call for:

- the environmental impacts of planned urban water supply systems to be checked for improvements, amendments and extensions likely to affect the acceptability of a project and the considered need for and benefits from it, against the background of country-specific value systems. (Simple unquestioning adoption of standards from the industrialised countries may lead to major planning errors.)

- an attitude of problem-awareness directed to regional conditions to be created among project planners and population in connection with the environmental implications of water consumption. (Policies restrictive of consumption in areas short of water and areas at risk ecologically, the importance of introducing cost-covering tariffs, the implementation of statutory codes and regulations).

- careful on-site investigation of conditions, such as what the requirement is, water availability and quality, the regenerative capacity of the resource, the risk of pollutant intrusion, and impacts of water abstraction on the ecology, with the services of specialist multi-disciplinary bodies being called upon to deal with particularly involved questions (depletion of water resources, consequences of water table lowering).


These on-site investigations must also cover the condition of existing systems and an assessment of existing shortcomings and obvious errors in the techniques employed likely to have repercussions on the improvement of the existing systems and practices.

The local investigations should pay particular attention to socio-economic questions, such as family income, income of women, stress on women caused by transporting water, attitude of the population to the scarcity and importance of water as a resource, willingness to pay, and other questions such as the willingness of the population to assist in keeping a watch on the efficient use and distribution of water and to play some part in repair work.

- assistance with the setting up of indigenous monitoring bodies to ensure that the requisite environmental precautions specific to the project are taken.