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close this bookWater Supply: Water Supply, Wastewater, Irrigation - Initial Environmental Assessment Series No. 7 (NORAD, 1994)
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Environmental impact assessment (EIA) of development aid projects
Initial environmental assessment.

Oslo, June 1994

Norwegian Agency for Development Cooperation NORAD
P.O. Box 8034 Oslo Dep., 0030 Oslo. Telephone: 47 22
3144 00

Design: Petter Wang og Anne Kvalheim
Translated from norwegian by: Anglo Oversetterservice
Typesetting by: Akersposten/Ullern Avis
Printed: Reclamo, Oslo 1994


The natural resource base in our world today is exposed to constantly increasing pressures. Environmental problems are on the increase in developing countries as well as in developed countries. In developing countries, ecological stress strikes large and vulnerable population groups, and hinders social and economic development in many areas.

In 1987 the World Commission on Environment and Development, in their report "Our Common Future", described the problems we are facing, and the measures which must be taken to solve them.

Environmental problems in the developing countries makes demand on Norwegian development aid. Four Norwegian White Paper Nos. 36 (1985-85),34 (1986-87) and 51 (1991-92) on major questions concerning Norwegian aid to developing countries, and No. 46 (1988-89) on Norway's follow-up of the recommendations of the World Commission, have stressed the importance of taking environmental issues into account in Norwegian assisted development aid projects. In 1990 this was further articulated in the NORAD strategy paper "NORAD in the nineties". In the NORAD strategy document Part II "Strategies for bilateral aid" (1992) it is determined that all ongoing and planned development aid projects must be assessed with regard to environmental impacts.

This booklet has been compiled to help NORAD desk officers and planners to integrate environmental considerations into projects within water supply, wastewater management, and irrigation at an early stage in the planning process. It is one of a series of booklets presenting guidelines for environmental impact assessment (EIA) of various types of development projects. Experience and ideas from corresponding material compiled by other countries (OECD, the World Bank) have been integrated in this EIA-system.


An initial assessment has the objective helping project desk officers and planners to assess a project in relation to environmental impacts. The initial assessment shall provide a survey of environmental impacts likely to ensue if a project is implemented. Usually an initial assessment will be based on easily accessible information, former research, the local population's views, etc.

Only potential environmental impacts, direct and indirect, are identified in the initial assessment. Estimates are not assumed to be substantiated by special accounts or registrations, but rather come under a full assessment. An initial assessment ought to be mastered by personnel without specialist knowledge of that particular project type, or of environmental consequences in general. In the course of an initial evaluation, the project desk officer may nevertheless find it necessary to consult environmental expertise.

The initial assessment should attempt to clarify both positive and negative environmental impacts. However, since the major positive effects are usually included in the main project account, the initial assessment will tend to lean towards potential negative impacts.

The EIA-system affords no easy solutions to weighing positive and negative aspects against one another in a decision-making process. This is because there are seldom clear objective criteria or threshold values for which environmental effects are acceptable or not.

This booklet provides a survey of required information as well as questions that need to be answered in an initial assessment of projects and activities within water supply, wastewater management, and irrigation.

To offer a brief overview of the subject, Part I describes what these project categories normally comprises, and what environmental impacts in particular can be expected. It stresses an account of the special problems often faced by projects and activities in developing countries and tropical areas.

Part II offers a more specific account of the kind of information that ought to be available as well as questions that should be answered in an initial assessment of projects.

1.1 Introduction

In addition to water supply, wastewater management and irrigation, this booklet also mentions water resources management, sanitation and water-related health aspects. Water is important for all life and human activity. Water is also a basic ingredient in hydropower development, agriculture, industry, aquaculture etc.. It may therefore be relevant to refer to other initial assessment booklets in this series when considering environmental impacts related to use of water.

The Earth is often termed "the blue planet" because water is the dominating component of the surface. Nevertheless approximately 1.2 billion of the world's population have inadequate water supply, and approximately 1.8 billion lack satisfactory sanitation conditions. In the course of the last decade the global water supply situation has improved slightly, while the situation as regards sanitation and drainage has not improved when viewed in relation to the population growth. There are many indications, however, that the water supply situation will deteriorate, especially in cities and densely populated areas. Prognosis show that by the year 2000 some 40% of Africa's population will be urbanised - and 50% by the year 2020 (NORAD/NVE). Access to water resources is already critical in many city areas, where both surface sources and groundwater sources may in addition be contaminated.

In many developing countries the large population growth creates competition and conflict as regards the water resources. Increased consumption of water for various purposes has lead to pollution problems. At the same time deforestation, soil erosion, desertification, salinization etc. will change the size and quality of the water resources. Poverty and need can be a substantial cause to environmental destruction and pressure on the water resources.

1.2 Management of water resources

An environmentally sound management of water resources demands a holistic planning which takes into account the relations between social, economic and ecological aspects in the whole watershed area. The various measures or activities as regards water resources are considered in this context. Integrated water resources planning can function as a total framework to which development projects and measures are subordinated. Management plans have, however, limited value if they are not based on a political will and the means to implement them. Political agreement as regards the management of water resources that are common to several countries may be especially complicated. According to UNCED 1992, Agenda 21, it is a principle that water management and planning should be implemented at the lowest relevant administrative level. This may entail transfer of responsibility from central political levels to local levels where the authorities in close co-ordination with the users and entrepreneurs take over all or parts of the management responsibility.

Water must be regarded as both a social and an economic benefit. By valuing the water economically and by setting a price on the water to the user, more efficient usage can be achieved This is especially important in areas where water is, or can become, a scarce commodity. In arid areas there are examples of cities where there is a re-utilisation of water at a rate of over 90%, while other cities re-cycle very little. Pricing of water can adversely affect the poor sections of the population who have inadequate means of payment. However, this problem is attempted addressed through various price mechanisms and differentiation of prices.

Water resources management with the objective of improved water supply can result in a series of measures in the watershed area, e.g. conservation of forested areas, activities to reduce pollution from agriculture, animal husbandry and industry, erosion prevention measures, specific considerations as regards construction activity and infrastructure etc..

1.3 Project types within water supply, wastewater management, sanitation and irrigation

Roughly, measures within these sectors can be classified under one or more of the following:

· Establishment of practical facilities for water supply, management of sanitation problems, wastewater management and irrigation that are economical in terms of resources. This may also entail rehabilitation and/or expansion of existing facilities.

· Technical, professional or financial strengthening of institutions and authorities to ensure the long-term functioning of the facilities.

· Establishment and follow-up of operation and maintenance programmes, training of personnel, consultancy services, and user-oriented awareness campaigns on health and hygiene.

· Assistance to establish overall management plans for water supply and wastewater treatment.

· Assistance with regard to development of legislation, strategies and research.

1.3.1 Water supply

a) Water for households

Water supply projects are often initiated with the objective of ensuring adequate health and hygiene conditions for the population. A safer water supply may be important as regards water-related diseases (cf. chapter 3.3). The time saved with regard to the time and effort previously used for water collection can be made available for other activity. In most countries this may be an advantage for the women, as they usually have the responsibility for collecting water. Improved water supply can also benefit the welfare measures as regards care of children, reduce the frequency of diarrhoea among children, and improve the general health.

b) Water for other purposes

Water is part of the production processes in many types of industries, agriculture and other economic activity. The potential for development of an area or region will in most cases be dependent on the access to water. Certain activities, i.e. mining, may require large amounts of water. As regards demands to water quality, the food industry for instance requires a high degree of water purity (cf. other initial assessment booklets).

c) Choice of technology and institutional considerations

Groundwater sources and surface sources are the two main sources of water. However, various techniques for rainwater harvesting may also be relevant (cf. chapter 2.2 on the characteristics of these sources).

At the village level water supply based on groundwater sources usually consists of several wells located in the area without any comprehensive purification facility or distribution system to the households or other users. As regards groundwater wells one distinguishes between open wells dug by hand, or wells drilled by machines. From the open wells the water is usually brought to the surface through the help of buckets and winches, while from the drilled wells the water is brought up by hand pumps or motor-driven pumps. If pumps are used one must ensure that the maintenance and servicing facilities needed are accessible locally. Localisation of wells and pumps is primarily done in accordance with hydrological assessments, but the final localisation must take the local population's desires and needs into consideration. One must ascertain if there exists plans, traditional rights, taboos, specific ownership or user aspects, or other restrictions to potential well sites. The well sites must be protected against infiltration of wastewater or seepage from latrines or other pollution elements. If the groundwater is to be used in larger water supply units, for instance to cities and industry, motor-driven pumps must be used. Systems based on solar energy may become more widespread. The advantage with this source of energy is that it is renewable and does not pollute. Other environmentally beneficial sources of energy to water supply systems on a smaller scale may be windmills, water-wheels and big-gas generators.

Surface sources are usually most relevant for supply of large amounts of water to households, industry, irrigation and power supply. But surface sources can also be utilised for small scale water supply. At village level surface water can be purified for use in households through relatively simple sand filtration techniques. Surface sources can constitute the basis for large water supply facilities with purification and disinfectation units for supply to cities and densely populated areas. Collection of water in reservoirs may be necessary to ensure stable water supply during dry periods. The reservoirs may vary in size from small dams to large reservoirs or artificial lakes. Transfer of water from one area to another through the construction of canals and dams has been tried in some areas in the world, but this represents costly and land demanding methods of water supply.

Water harvesting can be an important supply source many places. This can be done by the individual households or by the establishment of a common facility where it is possible to collect rainwater directly or from roofs or cliffs through the establishment of earthworks or terracing in the terrain. The collection of dew dripping from trees following a cool night in warm areas may also be relevant.

In arid or semi-arid areas with access to saltwater various forms for de-salinization, e.g. distillation, membrane processes or ion-exchange methods, may be used in order to make the water suitable for water supply purposes. The de-salinization process methods entail fairly expensive investments and running costs, and large amounts of energy.

All types of water supply require that one considers aspects like organisation, administration, access to qualified personnel with relevant experience, local participation and the possibilities for funding of operation and maintenance. Some projects may require that the technology chosen is known and accepted locally and is user friendly (appropriate technology). At village level there are examples where locally produced technology, though technically not the most advanced, has given the best solutions. In rehabilitation and upgrading activities the choice of technology is to a large extent determined by the existing facilities. In such cases an evaluation must be made of the existing technology determining whether there is a basis to continue utilising this technology or if new adapted solutions should be chosen. Women are often a primary target group when it comes to choice and adaptation of water supply systems to households, and the needs of this group should especially be considered.

1.3.2 Wastewater management and sanitation a) Objectives

Development of water supply has in some places been implemented without giving enough consideration to sanitation and an adequate treatment and disposal of wastewater. The operation of the existing wastewater purification facilities may be inadequate. Uncontrolled discharges and irresponsible handling, in addition to poor sanitation, can have several negative environmental and health impacts. Poor sanitation solutions may cause a water supply system to increase the spread of disease instead of reducing it. The treatment of wastewater and improval of sanitation should in some cases be an integrated part of water supply projects.

The objectives of projects within wastewater management and sanitation are to reduce the discharge and spread of infectious and environmentally detrimental substances, treat wastewater and faeces so that both water and the nutrients can be utilised for other purposes, and reduce the contamination of groundwater and surface water to ensure utilization. Project components and activities can include establishment of pipelines for collection and transport of wastewater, pump stations, various treatment methods, purification, discharge and re-utilisation of wastewater, various small-scale sanitation systems for villages and cities, and measures to drain rainwater in the cities.

The projects must be based on satisfactory data on type and volume of the waste matter present, institutional aspects, and the characteristics of the environment. Substances which may be present in wastewater and which can cause considerable pollution are organic substances, nutrients (e.g. nitrogen and phosphorous), salts, contagion (infective agents - pathogens), toxic substances (e.g. heavy metals, pesticides), oil residue, particles and solid matter (cf. chapter 3.2 for a description of the impact of these substances on the environment). Given an adequate planning, an appropriate technology, and that the operational phase ensures proper maintenance and care, the projects within wastewater management and sanitation should generally have a positive impact on the environment.

b) Choice of technology and institutional conditions

There are several alternatives as to choice of technology and location of sanitation facilities and facilities for collection, treatment and deposition of wastewater, plus use of sewage sludge and compost. Some of them are briefly described below.

Project types and technology choices will usually vary between village and cities. At village level the technical solutions can be simple, but the institutional and social aspects are nevertheless important. Local institutions must be able to manage and maintain sanitation systems and any wastewater treatment plant or system. Local participation may be the key to success. Sanitation solutions on village level are often confined to various latrine solutions, of which the infiltration latrines, dug by hand or drilled, and compost latrines are the best environmental choice. Measures to motivate use of latrines must take culturally based attitudes into consideration (cf. chapter 2.3). Latrine solutions may be combined with deposition of organic waste. The compost from such facilities may be used in agriculture. Water closets are expensive and require relatively large amounts of water, drainage systems and purification units.

In the cities there may be a need for measures for development and rehabilitation of pipelines and purification units for sewage. Wastewater should not go in the same pipes as rainwater, so-called combined sewers, if these pipes are not constructed in such a manner that they have capacity for this. In many cases it may be practical and economically sensible to link industrial wastewater systems to public sewage systems, given that there exists adequate systems for prior treatment of such discharges. In cities and densely populated areas where sewage purification systems have already been installed there may be a need to introduce solutions for re-utilisation of purified wastewater for other purposes in the vicinity, e.g. aquaculture, agriculture and irrigation.

Procedures for treatment of wastewater in tropical areas can vary from those used in temperate zones. Simple techniques, for instance stabilization ponds, can utilise the advantage of the warm climate and reduce the costs of treatment. Re-circulation may be relevant to save water, but may entail high investment costs. Treatment of wastewater before re-utilisation or discharges can be classified in accordance with the level of purification; primary, secondary or tertiary. The level of purification is dependent on which substances are found in the waste water. Both anaerobe [Without air) and aerobe (with air) conditions may be utilised in ponds and lagoons for primary and secondary treatment. Where the area is too small for ponds, oxidation (aerobe) ditches can be an alternative. Various filtration methods exist for secondary treatment. And various tertiary treatment methods exist for the removal of specific substances in the wastewater. These may be complex in development, use and maintenance, and require highly qualified personnel. Use of chlorine occurs to purify wastewater and sources for drinking water to reduce the amount of contagion. If used incorrectly, chlorine may lead to pollution and cause environment and health damages.

Sludge from purification units may be used as soil enhancement for agriculture, forestry, and grazing if industrial waste has not been released in the sewage system with the resulting risk of heavy metals and toxic substances in the waste. Filtration of wastewater to groundwater sources may be done in cases of water shortage and where the soil has the capacity to filter pollutants before the water reaches the groundwater. Lakes, rivers and marine areas are relevant surface recipients. The pollution impacts will vary depending on the degree of prior purification and characteristics of the recipient (cf. chapter 3.2). Separate standards as to the discharge contents and demands to water quality may exist in the individual countries. If not, the guidelines issued by the World Health Organisation (WHO) may be useful.

1.3.3 Irrigation

a) Objectives

Irrigation, or artificial watering, has as its primary objective to increase agricultural production. Some places irrigation, through the establishment of large irrigation systems with canals and dams, has been practiced for more than 5000 years. Many see a close relationship between the efficiency of such irrigation and stability in the civilizations, also termed hydraulic cultures or regimes which through history have evolved around the irrigation systems. Irrigation makes it possible to cultivate areas with little rainfall, stabilise water supply in regions containing large variations of annual rainfall, increase the extent of cultivated areas, plus increase the harvest frequencies to two or more per year.

Some countries in arid areas, or in areas with large seasonal variations in rainfall, are very dependent on irrigation. In order to meet the food needs of a rapidly increasing population the development of irrigation has been extensive during the last 30 years in many developing countries. The development is in several places related to settlement projects where many people migrate to new areas. The objectives can be to offer landless new possibilities or to relieve areas with a high population density. This has in reality lead to a situation where most areas that are suitable for irrigation have already been developed.

Studies have revealed that the utilisation of the water resources in many irrigation systems is not optimum, and that much can be gained by a more efficient utilisation of water to reduce waste. Activities addressing these aspects can be maintenance of canals and other irrigation structures, altered water resources management and distribution' and better co-ordination of the timing of water deliveries to coincide with the start of cultivation processes. The target should be enough water to the right time, equally distributed over frequently great distances. The environmental impacts from irrigation can be substantial if the aspects of water resources management and the considerations of local natural aspects are not respected (cf. chapter 3.6).

b) Choice of technology and institutional conditions

Various types of irrigation can be used depending on the local conditions, crop types, and the type of water resources that are being utilised. Rivers, dams and reservoirs, and groundwater sources are relevant both for large- and small-scale systems. Large-scale irrigation systems usually utilise surface sources, especially rivers. However, the utilisation of groundwater sources has in recent years increased in some countries. The most common types of irrigation systems based on surface sources consist of networks of canals and/or plowed furrows to lead the water to the fields, often combined with sluices in rivers, pipes, and small and large dam facilities. Gravity is primarily used, but can be co-ordinated with the use of pumps. Drip irrigation is a type of irrigation which supplies water either in droplets or thin spray through holes in plastic pipes which are either buried in the ground or located on the surface. Sprinklers spraying the area in a simulation of rain are also used. These two methods represent new technology which is intensive in terms of money and management. But this technology also has the potential to reduce common irrigation-related environmental problems. Systems utilising gravity with the help of canal systems and terracing in sloping terrain, plus flooding, are characteristic of rice cultivation. While drip irrigation is often used to water perennial crops, e.g. coffee and vegetables, and in plantations and nurseries.

Groundwater sources being used for irrigation must be rechargeable. In larger systems where the water is pumped to canals or sprinklers and drip irrigation, the sources have to be monitored closely. Small-scale irrigation can be developed by simple methods where the groundwater table is close to the surface. Pumping or manual lifting of the water from wells, represents low costs. Collection of water from streams, surface run-off, and precipitation by building small dams is common. The dams are simple to maintain, and have proved to be a successful form for irrigation, both with regard to water resources management, crops and environment. The rivers can form the basis for the construction of larger dams and reservoirs, often with the common objectives of irrigation and hydro-electric power supply (cf. booklet 6. Hydropower development). Wastewater is often used for irrigation and can represent a sensible type of reutilisation where water resources are scarce, given that the wastewater does not contain heavy metals and toxic substances in concentration levels that are hazardous to the environment and humans.

The soil's chemical characteristics, infiltration capacity, and capacity to retain humidity should be considered in irrigation activities. Many types of irrigation place great demands to good drainage, and there may be a need for drainage canals to lead excessive water away from the fields.

Planning and implementation of irrigation projects places specific demands to professional co-ordination where engineers, soil experts, hydrologists, health experts, social scientists and economists should participate. The projects must be planned carefully to avoid user conflicts. As regards rice cultivation a close co-ordination between farmers and the responsible authorities is necessary. In large irrigation systems this can be achieved by establishing water user organisations. Training programmes are especially important if irrigation is to be introduced in areas where it has not been practiced earlier.

2.1 The hydrological cycle

The greatest disparities as regards the distribution of water between regions are found in tropical zones. Large areas have generally poor rainfall, but there can often be substantial seasonal or annual variations as to rainfall amount. Humid sub-tropical areas can receive relatively large amounts of rainfall, which usually arrives in regular rain periods. Arid areas can be sub-divided into three categories; extremely arid (less than 60mm annual rainfall), arid (60-200mm), and semi-arid (200-700mm). Areas rich in rainfall can be sub-divided into humid (700-1000mm) and wet (more than 1000mm annual rainfall). There are several other types of categorisation, and what is perceived as humid or arid areas may vary from country to country.

Integrated water resources management and planning must build on an understanding of the hydrological cycle. The hydrological cycle can roughly be said to be the movement of the water from the earth's surface to the atmosphere and back. Important processes in this system are evaporation, transpiration (water vapour created through biological processes in nature, e.g. vegetation), condensation (through temperature shifts), cloud creation, precipitation, surface runoff water collection (in oceans, lakes, pools and ice) and infiltration in soil structure which both creates and replenishes groundwater aquifers. An intrusion in the hydrological cycle, for instance through a water supply activity, does not change the fundamental processes, but it may change the balance and their mutual relationship. The figure under illustrates the hydrological cycle.

The hydrological cycle

Natural characteristics of the terrain are of great importance to the balance of the hydrological cycle. Aspects like climate, geology, topography, vegetation and soil types play a considerable role. The latter three are especially important as to surface run-off, evapotranspiration (evaporation and transpiration) and groundwater recharge. In tropical areas evaporation is a major factor as regards the water balance. Removal of vegetation and reduction of the area shaded by trees and leaves may lead to less evapotranspiration but increased run-off. Surface run-off increases with steeper terrain and when the soil has a low infiltration capacity. Soil and vegetation cover may influence the hydrological cycle by reducing flood problems and securing water for the dry season through groundwater replenishment. This shows the importance of co-ordinating the management of soil, vegetation and water.

2.2 Characteristics of soil types, climate and various water resources

The soil in tropical areas is often low in organic material (humus) content and consequently has poor capacity to retain water. The soil is therefore especially vulnerable to human exploitation e.g. agriculture, animal husbandry, forestry, construction activity etc.. If damages are incurred to the vegetation cover there may be considerable soil erosion (cf. chapter 3.4).

The most important factor as to the amount of water in an area is the climate defined by factors like the variation of the precipitation and temperature in the area. Knowledge about the regional climate conditions, especially the seasonal variations, is an important requirement for the assessment of the suitability of the water sources and which environmental impacts an exploitation can lead to.

Some water source characteristics of importance for water supply activities are described below. The characteristics and quality of the water resources may be inadequately assessed in developing countries, and the existing data may be unreliable. The data base should therefore be considered thoroughly before the project is planned.

a) Surface water includes streams, rivers, natural lakes, reservoirs and dams. Due to the good dissolution capacity of the water, water will always contain various amounts of dissolved substances. The precipitation and the surroundings of the water source (geology, vegetation etc.) are decisive for the water's natural quality. Generally the water quality is more stable in large lakes where water normally has a long detention period, i.e. the relationship between the lake's volume and the received water per time unit, than in smaller lakes. Many surface water resources are used as recipients for wastewater. And run-off water from the water shed area can carry pollutants from various human activities. During flood periods the water quality will also be decided by the amount of erosion-related matter it contains.

b) Groundwater sources. Groundwater is led to the groundwater aquifers via precipitation and surface water. In arid areas groundwater is normally the most important, and many places the sole, source of water supply. Groundwater aquifers are relatively stable if not affected by human activity. Depending on the geological and hydro-geological conditions the groundwater may be quite close to the surface or very deep down. Some groundwater aquifers, for instance those we find in parts of North Africa and the Middle East, may contain large amounts of water. But these aquifers were in earlier geological periods covered by impermeable rock which prevented replenishment from surface sources. These so-called fossil groundwater aquifers may have stayed unchanged for thousands of years. Since they cannot be recharged by natural means, they must be considered a non-renewable resource. Even though groundwater is well protected against pollution, a series of potential risks exist which should be considered as to possible utilisation of groundwater. A mapping of possible existing and future risks concerning the relevant groundwater source should be implemented. Due to the long detention period of groundwater, a contamination of the groundwater may render it useless for other use for a long time.
c) Rainwater. Water supply comprising direct collection of rainwater etc. is normally based on local initiatives. The environmental impacts of rainwater use are usually small, but it is important to be aware that airborne pollution may reduce the water quality (also cf. chapter 1.3.1c).

2.3 Socio-cultural conditions

The socio-cultural conditions related to water sources, water resources management, and sanitation can vary substantially from country to country, culture to culture, and between rural and urban areas. One should especially focus the issues of ownership rights to water resources, the women's role and relationship as regards water sources and water usage, taboos and symbolic values connected to water and sanitation, local traditional technology, local management and institutional structures, and the expressed needs and priorities of the local community.

Ownership rights to water may represent a considerable power factor in the local community if individuals retain this right rather than the respective users. Many places access to water is an individual right, based on water fees. However free access is also practised, for instance in some irrigation systems. Access to wells and other water sources may in some countries be based on caste or religious identity. There are also examples of specific ownership rights limiting the access of women to water sources; for instance men's ownership rights and management responsibility may limit the possibility of women to participate in deciding where a water pump is to be located.

In many cultures it is women, and sometimes children, who have the responsibility to secure water to the individual household. The women must therefore have special knowledge on where and how to find water, and find solutions when resources are scarce. This knowledge is often disseminated at the water source itself, which may also represent an important information-sharing centre for women. Where natural conditions (e.g. drought) limit the access to water, some women may use many hours daily to fetch water. In slum areas or the outskirts of cities there are often few water points, and the quality of the water may be poor. Water must therefore be fetched from sources outside the city. In gender-segregated cultures adult women may have limited liberty to show themselves in public, and the children end up with the burden of fetching water.

Water may be assigned strong symbolic values in some cultures, and be important for rituals and presentations. Water can for instance be associated with fertility, and groundwater can be regarded as a metaphor for kinship with subterranean life. As an aesthetic landscape factor the water in rivers, lakes, waterfalls, canals, dams etc. plays an important role. And water also plays an important role for the population's sense of belonging to an area.

Tradition and religion may have importance for the way a population relates to sanitation. In some cultures there may be relatively complicated rules as to who can use the same latrines. There are examples of father not being able to share latrines with married sons, and father in law not being able to share latrines with sister in law. When such conditions exist separate latrines are required. There are also great differences between cultures as regards touching faeces. In some cultures one must avoid contact, while one in other cultures will utilise the waste from latrines for various purposes.

The specific knowledge irrigation demands from for instance rice farmers, may yield status in the local community so that farmers practicing irrigation have a higher ranking than other farmers.

Conflicts regarding water and social unrest related to management of water resources exist in many developing countries. These may range from international conflicts and struggles between nations to secure water rights, to local conflicts as regards how water for irrigation shall be spread over large distances and between many farmers. It is not uncommon that water is acquired illegally, stolen from canals, or that sabotage occurs on irrigation systems.

The institutions responsible for water supply, wastewater management, sanitation and irrigation may be inefficient. This may be due to lack of material and economic resources, and inadequate competence and legislation for the regulation. In addition the responsibility for water management may be divided amongst several ministries and institutions with a weak degree of co-ordination and clearly defined responsibilities.


This overview is concerned with direct as well as indirect environmental impacts. It is often difficult to draw a clear distinction be tween these two types. Direct environmental impacts can be attributed to certain characteristics as regards water supply, wastewater facilities, sanitation, and irrigation. The indirect impacts may, however, emerge as a result of other types of activities that projects entail, or that projects in one way or another affect cultural or other socio-cultural conditions in the project area.

This survey also presents proposals for measures to mitigate possible negative environmental impacts.

The environmental impacts described below are based on the information concerning the characteristics of the projects (chapter 1) compared with the descriptions of the environment the projects affect (chapter 2).

3.1 Excessive exploitation of the water resources

Projects within water supply must be considered on the basis of adequate data. In many countries the data on the condition of the water resource may be inadequate both in terms of quantity and quality. At the same time the existing utilisation may be taking place in uncontrolled forms.

The extraction of groundwater can cause the groundwater table to sink if the extraction rate is larger than the natural replenishment and recharge of the resource. Reduced water supply capacity and production are the result. Wells and boreholes which are to be equipped with hand pumps usually have so small an impact that there is little danger of the groundwater table sinking. However, in extreme drought situations the replenishment can be so small that such wells may go dry if they have been made too shallow. Though the groundwater table does sink in periods, and is usually restored again after periods of good rains, even a brief impact may be critical for the users. In projects that include establishment of many wells with motor-driven pumps or facilities for supply of water to a city, the technical factors are present that may cause a permanent lowering of the groundwater table. This may be a risk even if the projected capacity of the system is considered to be on the safe side. Large irrigation facilities demand large amounts of water, and can cause excessive exploitation of the groundwater aquifers.

The lowering of the groundwater table may cause settling damages to buildings, and lead to reduced or dry vegetation in the vicinity. The water quality in the groundwater aquifers that are excessively exploited may be reduced through salinization of the water. Special consideration should be given as regards the utilisation of groundwater resources in coastal areas, where sea water may enter the groundwater aquifers.

The extraction of water from surface sources e.g. streams and rivers can reduce the respective downstream flow. The extraction volume of water must be decided in accordance with normal and low water flow. If the extraction is large compared to normal water flow, the impacts downstream must be considered. This especially pertains to projects that include transfer of water from one watershed area to another area and extraction of water for irrigation purposes. Increased evaporation may also reduce the re-circulation stream or return water flow. Reduced water flow will have impacts on other usage and the ecology of the water resource. Pollution problems may increase due to reduced dilution. The discharge of wastewater to the same water resource may compensate for the extraction (cf. chapter 1.3.2 and chapter 3.2). The impacts of extraction of water from lakes, dams and reservoirs is described in chapter 3.5.
Measures that utilise surface sources, or which cause substantial changes in the watershed, may change the run-off pattern, reduce the infiltration, and thereby impact the replenishment of the groundwater aquifers. Over time the sum of various activities, or a considerably large project, may cause a permanent lowering of the groundwater table. The impacts of various measures in areas with important groundwater aquifers must therefore be carefully considered (cf. other EIA booklets).

In connection with water supply and irrigation projects one must especially consider the level of utilisation and capacity in the seasons with little rainfall and the long-term variations in the precipitation cycles. In arid and semi-arid areas where surface water resources are limited and there is a slow recharging of the groundwater, it may be necessary to establish strict priorities as regards the usage of water. Use of price mechanisms is one method that is being used increasingly.

3.2 Pollution problems

The danger of polluting the drinking water is greatest in cases where the same water source is utilised as source of drinking water, recipient for wastewater, and various other purposes e.g. laundry, washing of tools, bathing etc.. Where possible the source of drinking water should be located upstream of discharge points and other sources of pollution. Also in the case of smaller groundwater based facilities in villages one must protect against such sources of pollution, especially in connection with open wells (also cf. chapter 3.3). Inadequate or incorrectly located latrines, plus livestock which drink from waterholes and open wells, will reduce the quality of the drinking water. Waterholes or open wells are generally more vulnerable to pollution than drilled wells with water pumps. Waterholes and open wells can also be polluted by small animals falling into them. Use of covers can reduce this problem. When animals are butchered and their entrails are deposited in areas draining to a drinking water source, disease may be transmitted to people if the animal has been a carrier of contagious organisms. Surface sources may be polluted if large numbers of birds reside there. Other activity in the watershed area like agriculture, animal husbandry, waste deposits, plus accidents e.g. leakage from oil or chemical tanks, traffic accidents to tankers etc., and damage to water pipelines may cause substantial pollution of water sources (cf. other EIA booklets in this series). In the case of large groundwater facilities it may be relevant to protect a certain area to limit the risk of contaminating the groundwater. Discharge of raw or poorly purified wastewater may contain considerable amounts of infective bacteria, particles, and waste material. The discharge point should therefore not be at the edge of the water, but be immersed in the river itself and be led out to deep water in lakes or oceans.

Material or substances which can cause substantial pollution problems, and which are common in wastewater are:

· Organic material: Fragments of decomposed biological matter, excrement etc.. Discharges to water sources may alter the oxygen balance and create anaerobic (oxygen-free) conditions. This can cause fish death and alter the composition of species. Bad smell and taste may ensue because of gas development in the water.

· Nutrients: Nitrogen and phosphorous are especially important. The introduction of these nutrients can lead to eutrophication, algae blooming and growth.

· Salts and minerals: Large concentrations of salts, for instance nitrates, in drinking water can be harmful to the health of humans and animals. The channelling of wastewater containing salts to cultivated areas can cause salinization of the soil.

· Contagion: Wastewater may contain large amounts of micro organisms, some of which induce disease (pathogenic).

· Toxic substances: Heavy metals like mercury, cadmium, lead, and artificially created organic substances that cannot decompose, e.g. the residue of chemical pesticides, are often found in waste water. Many such substances can accumulate in food chains. In rare instances radioactive substances may also be found in wastewater.
· Oil residue: Dependent on the type of industry in the area the wastewater may contain oil. Oil and fats can also stem from households. The toxicity of the oil may vary greatly in accordance with various chemical compositions.

· Particles: Wastewater can contain large amounts of particles which may cause siltation of the water source, damage to technical facilities etc..

· Solid matter: Some substances in wastewater may be classified as solid matter; e.g. paper, textiles, and plastic. In addition to a visual degradation of the water source, the solid matter may affect other activities.

As regards discharge to lakes one must consider that lakes constitute part of a larger run-off system which includes rivers and streams in addition to run-off and seepage water from the watershed area and groundwater sources. The introduction of pollution to the lake can therefore come from various sources, also upstream through transport by water. When assessing the impacts of fresh discharges the existing sources of pollution must also be mapped, for instance through water quality studies or the development of so-called theoretical pollution accounts. In this context new discharges of wastewater can be considered in relation to the total existing discharges.

Rivers have a certain self-purification mechanism which is due to a quicker decomposition of organic material, dissolution and dilution of wastewater, and a natural decomposition of pathogenic organisms. This self-purification mechanism is dependent on the length of the river and conditions like flood level, turbulence, temperature and flow velocity. Common pollution impacts of wastewater to lakes and rivers are decomposition of organic matter which may disturb the oxygen balance, discharge of nutrients (primarily phosphorous and nitrogen), which stimulates algae blooming and may cause vegetation growth. In addition chemical pollution may reduce the diversity of species through the introduction of substances (environmental toxins) which enter the food chain through algae and fish.

Discharges which are defensible in rivers may cause considerably more serious impacts in estuaries. An estuary is an area at the mouth of a river or a bay where the water is a mixture of sea water and freshwater (brackish water zone). Such zones are among the most biologically productive areas in the world, partly because the tides cause a rapid circulation of nutrients, and partly because of the great diversity of species. The ecosystem can here be extremely vulnerable. The pollution impact is dependent on the capacity to blend which is decided by the flow of freshwater and the tide activity. The stratification of the water may imprison the pollution. Generally wastewater should not be discharged in estuaries.

Sea water has a large capacity to receive and dissolve wastewater. Controlled discharges of wastewater to marine environments through a planned localisation of discharge points and technically adequate discharge pipes may be a simple solution to wastewater problems of coastal communities.

Groundwater sources are in principle better protected against pollution than surface sources. Soil and rock generally have a good capacity to retain or hold back pollution. However, these capacities vary so that assessments are necessary in order to ascertain the retention capacity. A groundwater source which has been contaminated must be considered destroyed since it may take a very long time to become pure again. The discharge of wastewater to soil may under specific soil, geological and topographical conditions cause nutrients to reach the groundwater. A high content of nitrate can affect the quality of the groundwater and have negative effects on the health of the users. The nitrate content in groundwater sources must be ascertained prior to usage as drinking water. If pollution has reached the groundwater table, or there is a danger of such, pumping should be stopped to avoid drawing the pollution towards the wells. The risk of contamination of groundwater sources is great in areas with a high groundwater table and in areas which are periodically subjected to floods where direct contact between surface water and groundwater can ensue. Pollution sources, for instance sanitation facilities, should not be located to such areas. A high content of iron and minerals in the groundwater may be undesirable, and acidic water may cause corrosion and destroy water pumps in a relatively short period. The grease used in some pumps can pollute the drinking water causing an unappetizing film on the water surface. All activities involving extraction of groundwater should be accompanied by a monitoring programme with reporting routines which register groundwater levels and water quality.

In addition to the above, smell and noise can be a pollution problem as regards treatment processes for wastewater and sludge disposal. These problems can be mitigated by a protected localization of facilities and use of soundproofed machinery.

Irrigation may, through canals, lead to the spread of waste matter and residue of pesticides. If wastewater is used for irrigation as part of a re-utilisation strategy, pollution may ensue if the wastewater is not properly purified.

3.3 Water-related health problems

Water has the characteristic of being both a carrier and a cure for diseases. In some cases a water supply facility can cause a reduction of the prevalence of one disease, but increase the frequency of another. The planning of water supply projects must take adequate consideration to health and hygiene to avoid increasing the prevalence of diseases. In the case of irrigation projects and establishment of dams, water-related diseases may increase considerably. Pollutant discharges from re-circulation and purification units, in addition to groundwater contamination from disposal areas for sewage sludge, can cause health problems. Maintenance and control are often crucial to limit these impacts.

Water-related diseases can be acute or chronic and be classified in four groups:

1. Water-borne diseases are caused by organisms that survive in water and which if ingested can cause various diarrhoea diseases like cholera, dysentery, and typhoid fever. The emergence of these diseases is often related to drinking water supply and may cause wide-spread epidemics in areas with large water supply systems.

2. Water-washed diseases. Various infection diseases, for instance skin diseases, eye diseases and some types of diarrhoea can be spread by washing clothes and sick people in water also used for other purposes.

3. Water-based diseases. Various parasites and worms spend part of their life cycles in host organisms, for instance snails, which exist in water. When larvae are released these may infest people who are in contact with the water. Examples of such diseases are bilharzia and guinea worm.

4. Water-associated vector-borne diseases. Many surface water resources are habitats for insects which can relay diseases. One example is the mosquito, with the corresponding diseases of malaria, filariasis and yellow fever.

Some of the most common water-related diseases plus examples of measures to limit the spread of these are described below:

Schistosomiasis, also termed bilharzia, is caused by a worm living parts of its life in a snail before attacking humans. In rural areas one is vulnerable to infection during activities like irrigation agriculture, water fetching, fishing, laundry, plus bathing. The disease transfer risk can be reduced by having water sources for drinking, food preparation and laundry separate from water sources for agriculture and wastewater. The habitats for snails can be limited by avoiding stagnating water, removal of plant growth alongside ponds and canals, and ensuring good drainage and sanitation conditions.

Malaria and filariasis (elephantiasis). Both these diseases are spread by the mosquito. Malaria is transferred as one-celled organisms (protozoan) which reproduce in human beings. Filariasis is a roundworm. The adult worm lives in human lymph nodes, and the larvae (microfilaria) are spread by the mosquito. The spread of the disease can be restricted through elimination of reproduction sites for mosquitoes., like stagnating water or pools to small site elements like tin cans and old tires filling with rainwater. The aquatic growth can give good conditions for reproduction in larger pools. Canals and drainage must be maintained to create a constant movement in the water masses.

Onchocerciasis (river blindness) is due to a roundworm transferred through bites from a fly (the black fly) and is most common in Africa, but is also present in Latin America. The worm resides immediately under the skin of human beings. However, if the worm reaches the eyes blindness can result. The fly reproduces in floating turbulent water e.g. waterfalls and rapids. Insects are good fliers, and can fly more than 50km from the birth site. The disease can not be controlled by improving water supply and sanitation programmes. In some cases the disease may be controlled by for instance avoiding development of open sluices in connection with irrigation facilities and hydropower development which results in rapid flow of water and turbulence. Previously the only protection against the disease was to move from the area or introduce chemicals. However a medical drug has now been developed which makes the worms sterile and halts the reproductive cycle. It is therefore hope of controlling disease.

Guinea worm infects only human beings and is spread exclusively through infected drinking water. Approximately one year after infected water has been ingested one or more worms will project through the skin. The worms are approximately 1-2 mm thick, up to 1 metres long and use 3-8 weeks to exit (2-3 cm per day). Infected people can be sick and partly disabled for up to half a year, and can in worst cases suffer permanent disabling. The disease is wide-spread in both Asian and African countries, and can be prevented by relatively simple measures like filtering drinking water before usage and avoiding that infected persons approach the water sources. As soon as water is in contact with a worm, or the blister where the worm exits, thousands of larvae will be pumped into the water. If the worm's life cycle of one year is broken for two years the disease will be eradicated from the area.

Gastroenteritis diseases are caused by various pathogenic micro organisms (virus, bacteria, protozoa) which are spread through water which has been polluted by human excrement. The diseases include cholera, typhoid fever, and diarrhoea which may be serious for babies. The spread of the disease can be limited by halting faecal pollution by improving water supply to households and sanitation conditions. Groundwater is usually more secure than surface water. Disinfecting with chlorine or filtration may reduce the risk.

An important disease prevention measure is securing enough water for washing of hands and body, laundry, and other washing. This is especially important in order to limit the spread of disease through washing. The World's Health Organisation (WHO) has developed recommendations for volume of water per person and standards for water quality. The drinking water is often contaminated after the water is collected or during the collection through the utilization of dirty utensils or cups which have lain on the ground. Instruction as regards hygienic treatment of water should be a part of the water supply project. To avoid stagnant water by the well proper run-off should be ensured through for instance the construction of concrete gutters.

In cities and densely populated areas with water supply networks one can ascertain if an epidemic is water-related by comparing the expansion of the epidemic with the extent of the water pipe network. The causes for epidemics can be difficult to identify, but it is important that measures are initiated immediately to limit the spread. The spread of infection through drinking water is often due to a combination of random pollution and inadequate purification. Good purification units that are responsibly run are the best preventive measure. If epidemics ensue health authorities must immediately consider if restrictions as regards the use of water should be implemented.

Other health impacts related to water supply and drainage projects are the risks of accidents during the construction and operations phase, accidents as a result of gases in sewage systems, and accidents in connection with treatment of industrial waste and hazardous waste (cf. also booklet 11, Waste Management). Safety measures and training may be necessary to avoid accidents.

3.4 Erosion

Soil erosion is mechanical strain on the soil surface caused by running water, wind, waves etc., and constitutes as such an important geomorphological process. Soil erosion becomes an environmental problem when it exceeds in volume and velocity the natural production of soil causing the soil to be worn down and washed away. In tropical areas it may take between 200-1000 years to build up a new top layer with soil of 2-3 cm. depth. In many developing countries the water induced erosion is one of the most serious environmental problems where the annual erosion rate may exceed the natural renewal rate by 18-100 times. The main causes are human activities where the natural vegetation cover is removed or damaged through construction activity, transport, agriculture, grazing, forestry, mining etc. (cf. Other EIA booklets in this series). Various social factors like poverty and population growth may be underlying causes for intensification of agriculture in marginal or vulnerable areas with ensuing erosion.

There are three main types of water-induced erosion; splash erosion (caused by rainwater hitting the soil surface and moving soil particles), rill erosion (caused by water digging furrows in the soil surface in sloping terrain), and gully erosion (which is the formation of gullies or ravines). Increased erosion also causes increased runoff because the soil's capacity to retain water is dependent on the vegetation cover. This results in a reduced replenishment of groundwater, and an increased flow in streams and rivers creating an increased danger of erosion. A related problem to erosion is siltage. Erosion material carried by the water in streams and rivers may reduce water quality and cause undesirable deposition and sedimentation in other parts of the water source. The rate of nutrient introduction may exceed the natural rate and contribute to eutrophication in water resources. As a consequence spawning areas for fish may be damaged. Erosion material retained by artificial dams will sediment there and may reduce the life span of the dam and a possible electric power plant's production capacity (cf. booklet 6. Hydropower development).

Erosion, transport of sediments and sediment deposition are complicated processes. And the impact of activities may be difficult to predict. A cautious attitude should therefore underlie the project planning and implementation. Activities within water supply, wastewater management and irrigation have in common that they can be considerably adversely affected by existing erosion and at the same time can contribute to increased erosion. It may be relevant to implement erosion preventing measures in the watershed area as an integrated part of the projects. These activities may consist of planting, terracing, and securing forested areas and other vegetation to maintain a stable water supply.

Soil erosion as a consequence of measures within water supply and wastewater management is usually limited and local. In the vicinity of rural water points the erosion may ensue as a consequence of the strain on the vegetation cover due to grazing and trampling by animals and humans. This is especially the case in areas with extensive animal husbandry that are periodically subject to drought (cf. booklet 2. Animal Husbandry). Water and drain pipes laid out on the surface can become physical barriers and cause changes in the migration patterns of humans and animals, with the ensuing erosion in paths and trampled areas. This may be considerable in areas where the dry seasons alternate with periods of substantial rainfall.

Erosion is a common problem in irrigation, and it is difficult to avoid it completely. Irrigation canals are usually dug in soil where the canal walls are vulnerable to erosion, especially given a fluctuating water flow velocity. If the canal walls crumble large amounts of silt may be led out to the fields. Continuous and good maintenance in addition to a controlled water management, including not channelling floodwater into the canals, is necessary in order to avoid the problem. The canals may also be built of concrete, but this is expensive and may reduce the replenishment of the groundwater. The terracing often practiced in rice cultivation can result in erosion and landslides if the terrain is too steep and the vegetation is completely removed. Erosion may be caused in the case of drip irrigation in hilly terrain if the soil is not adapted to the method or if the irrigation intensity exceeds the infiltration capacity of the soil. As regards dam construction erosion may ensue in shore/bank areas. People who have moved from the inundated area to the watershed area of the dam may indirectly cause erosion, through for instance agriculture, which may harm the watershed area and contribute to siltation of the dam.

3.5 Specific impacts of regulation and construction of dams

A dam will alter the downstream flow of water. The flow may be substantially reduced, and the water source may in periods be dry. A positive impact can be that the reservoir has a stabilising function on the water flow volume, causing less variation in the water flow, something which may contribute to enhanced flood control. Large open water surfaces can lead to increased evaporation which may cause reduced volume of water downstream. The impacts of altered water flow can be registered all the way to the sea or ocean outside the river mouth. The water table level may change in areas surrounding a reservoir, and a lowering of the groundwater table downstream is a possibility if the water flow is reduced. Changes to the groundwater table can cause impact on the vegetation, the water supply from wells, and the stability of the bedrock formations. Due to less dilution reduced water flow may increase the concentration and damages of substances in waste and other discharges. Discharges upstream can reduce the water quality in the reservoir. The ecology and the aquatic fauna of the water source can be affected either directly through physical changes to the environment, e.g. a river running dry, erosion or barrier impacts, or indirectly through a qualitative and quantitative change of available nutrients and change of the reproductive conditions. The reservoirs can in addition be the reproductive centre for infective organisms (cf. chapter 3.3). The risk of dam breach must be considered due to the catastrophic implications such a breach would have downstream. A flood wave may cause loss of human life, animals, buildings, technical installations, harvests and soil. It is important to establish adequate safety procedures as regards the construction and operation of dams. Very large reservoirs can result in seismic impacts and local earthquakes with subsequent dam breaches.

Operation of multiple-use reservoirs is complicated and conflicts may arise between the usages of irrigation and hydropower. Irrigation demands high water levels, in contrast to flood control, where it is important to have low water levels in the reservoir. Detailed procedures should be established for the management of the reservoir under such hydrological circumstances.

A serious consequence of large dam developments is the removal of people who live in the inundated area (cf. chapter 3.8).

3.6 Specific impacts of irrigation

Common environmental impacts of irrigation in addition to the spread of diseases, erosion, changes in water flow and the removal of people (cf. chapters 3.3, 3.4, 3.5, 3.8), are waterlogging, salinization, alkalinization, and the washing out of soil. This especially pertains to gravity-based irrigation, and in a lesser degree to spread or drip irrigation.

The waterlogging of soil is caused if the watering exceeds the plants' consumption, the evaporation, and the drainage capacity of the soil. If waterlogging or water saturation occurs the groundwater table is lifted. Plants can thereby only utilise the top layers of the soil profile, something which is especially damaging to plants with deep root systems. A high groundwater table in the first part of the growth season can force the development of a shallow roots system causing the plants to be especially vulnerable in the ensuing dry seasons.

Salinization is the accumulation of mineral salts; sodium, calcium and magnesium in the top layers of soil, including the roots zone. A white scab, or powder, on the surface is characteristic of serious salinization. However, one will register a reduced harvest before the salinization is visible. The deeper layers of groundwater often have a higher content of salts than the surface water. Irrigation can cause the groundwater table to rise so high that the capillary forces of the soil pressures the water to the surface where evaporation creates a continuous deposition and accumulation of mineral salts. Salinization may also ensue if the water used for irrigation has a high saline content and intensive sun causes extensive evaporation. The salinization problem can be serious and has through history caused large areas of agriculture to be laid fallow. Currently over 50% of the soil in global irrigation systems is affected by salinization. Assessments show that the annual amount of land laid fallow due to salinization equals the amount of new area made available to production. The accumulation of salts can be reduced with good drainage, and/or avoiding use of water sources with a high saline content.

Alkalinization is not as common as salinization, but may cause even more serious damage to the soil. Groundwater or surface water rich in sodium which is used for irrigation can increase the concentration of sodium ions in the top layers of the soil through the same processes that cause salinization. Sodium changes the soil structure, makes the soil difficult to work with and nearly impenetrable for water. The alkalinization problem can be reduced by establishing deep horizontal drainage, adding large doses of organic fertiliser, or through permanent use of acids. Treatment requires thorough analysis and expertise.

Washing out of nutrients from the soil may take place if too much water is used.

Many of the causes of waterlogging, salinization, alkalinization and washing out can be removed by improving the management of water and the maintenance of the irrigation systems. The use of sprinklers and drip irrigation can also reduce the problems. Since large areas of irrigated arable land is laid fallow due to destruction of the soil it may be both cost effective and environmentally beneficial to invest in the rehabilitation of such areas rather than identifying new areas for irrigation.

3.7 Impacts for ecosystems, natural- and cultural landscapes and cultural relics

Some tropical environments have a great biological diversity and contain many conservation-worthy fauna and flora species.

Such ecosystems can be vulnerable to changes in the hydrological cycle, for instance in connection with a project which causes substantial changes to the water balance subsequent to the extraction of water. Ecosystems especially vulnerable to intrusions in the hydrological cycle are estuaries, wetlands, mangrove forests, delta areas, lagoons, littoral zones, shore/bank areas etc.. Relevant ecological impacts are discussed in the previous chapters.

Many water sources, both natural and artificial, are of considerable importance for the landscape's scenic content and the populations' sense of belonging to an area. Such water sources can be important landscape elements or landmarks. Activities within water supply, irrigation and drainage can change the landscape considerably. This especially pertains to the construction of dams, large purification facilities and canals. Careful shaping of facilities and installations, topographic adaptation and landscape maintenance should be considered during the planning and implementation of the projects. The projects can, at best, contribute to the beautification rather than the destruction of the landscape aestebtics and scenic value. Also in the case of smaller projects that do not have any substantial impact on the landscape must consideration be given to cultural relics, burial grounds plus sites or objects of religious importance.

3.8 User conflicts and other impacts for the community

Water supply, irrigation and wastewater management can through environmental impacts, the impounding of areas, and resource utilisation create competition and conflicts as regards access to a limited locality or resource. Conflicts due to use of areas may arise when interests and activities exclusively binds or impounds areas, and when there is competition between private and public interests. Surface water sources are in many cases multiple-use sources where various user interests place a variety of demands to the water volume, quality and area. At the same time these same users impact the environment, resource base and water quality. The bank and shore zones along water sources and the sea are especially vulnerable to user conflicts because many activities take place in these border zones between water and land, while at the same time the respective natural environments are often especially vulnerable. Water usage conflicts with negative environmental impacts are often due to urbanization and lack of co-ordinated water usage management. Land reclamation in the form of fill in of water ways, delta areas and sea areas is often chosen because the conflicts in relation to private land tenure are then usually less than the comparable acquisition of land area. Landfills may impact fishing areas or hinder sea transport. Conflicts between local and national user interests may arise. In later years the conflicts have increased between local traditional area and resource utilisation and the utilisation related to the tourist industry. The tourist industry is in several countries a national economic priority. Tourist industries place high demands to water quantity and quality, and may have the desire of greatest possible control of the water resources. This may cause problems for the traditional water usage for the settlements in the vicinity. Generally conflicts may force interests to utilise less suited areas like for instance marginal areas or vulnerable natural areas.

Water supply or irrigation projects can lead to an uncontrolled migration to the area by population groups establishing themselves in the vicinity of water supply facilities, distribution networks and canals, and subsequently stealing water from these. In addition to the subsequent competition for water resources, the new settlements can cause indirect environmental impacts through the activities of the immigrants, for instance agriculture. Social unrest is inevitable when establishing large-scale irrigation. The local population which has to move because of the project may suffer reduced living standards. Those remaining in the area may have their lifestyles changed as they must alter their traditional land use and agricultural practice. The target group for the project which moves into an area must adapt to new conditions, and maybe also lifestyles if irrigation represents a new and unknown production method. Conflicts may arise between the immigrants and residents as the residents have their access restricted to water and other natural resources. Measures to reduce the extent of such conflicts, e.g. training, information, and strengthening of institutions, should be carefully considered before implementation. Large population groups may be forced to move in connection with construction of dams. In addition to the social and psychological impacts this may cause, it is possible that various indirect environmental impacts will result in the settlement areas (cf. booklet 6, Hydropower development).

If the rural water supply and sanitation activities do not take adequate consideration to the desires, priorities, taboos etc. of the local population (cf. chapter 2.3), the result may be that wells and latrines may be left standing un-utilised. And conflicts may arise in the local community, for instance between owners and users or/and between genders.

4 Relevant literature

Brown, E.P, and Nooter, R. 1992: "Successful Small-Scale Irrigation in the Sahel". World Bank Technical Paper No. 171. Washington D.C.

Cairncross, S. 1992: Sanitation and Water Supply. Practical Lessons from the Decade. DP number 9. Water and Sanitation Discussion Paper Series. IBRD/World Bank.

DANIDA, 1988: "Environmental Issues in Water Resources Management", Ministry of Foreign Affairs/DANIDA, Copenhagen, Denmark.

Le Moigne, 1992: "Country Experiences with Water Resources Management. Economic, Institutional and Environmental Issues". World Bank Technical Papers No. 175. Washington D.C.

Le Moigne, G. Barghouti, S. Garbus, L, 1992: "Developing and Improving irrigation and Drainage Systems". World Bank Technical Papers No. 178. Washington D.C.

Kristoffersen, Herald, 1986: "Water Management and Land Use Intensity in Irrigated Paddy Cultivation. The Kirama Oya Basin and The Urubokka Oya Basin, Hambantota District, Sri Lanka", NORAD, Oslo.

McCommon, Carolyn, 1990: "Community Management of Rural Water Supply and Sanitation Services". UNDP/World Bank Water and Sanitation Programme.

NORAD, 1990: "Water and Sanitation. Towards Better Health and Improved Quality of Life". NORAD, Oslo

NORAD/NVE, 1990: "Water and Sanitation: NORAD's policy at the end of the water decade". Seminar report, Oslo.

UNEP, 1982: "Environmental Guidelines for Irrigation in Arid and Semi-Arid Areas". UNEP, Nairobi.

UNEP, 1982: "Environmental Guidelines for Watershed Development", Nairobi, Kenya (Ed: Yusuf l. Ahmad)

UNEP, 1988: "Environmental Guidelines for Domestic Wastewater Management". UNEP, Nairobi.

1 Project description

As a basis for initial assessment, a description of the project must be available. In most cases it will be relevant to present several alternative technical solutions and localities. Activities in the construction phase as well as the operational phase of the project must be included.

This description will to a certain extent be based on the regular technical and economic description of the project, possibly after consultations with project planners or other relevant institutions in the country in question. The following questions aim to elicit information that is relevant with regard to environmental impacts. Relatively detailed information may be required concerning production processes, use of inputs, localisation etc.. The information resulting from the initial assessment can be included in the project document being presented for approval. In the case of more comprehensive projects, the information can be collected in an appendix to this document. The following specifies what is considered as essential background information for an initial environmental assessment:

a. The need for the project. Give a brief description of how the need for the project has emerged. What are the purposes of the project? Who are the target group(s) among the population? Is the project focusing one or more parts of a more extensive system within water supply, drainage or irrigation? Will the project entail new construction or upgrading of existing facilities? Are activities within other sectors, such as industry, tourism etc., expected as a result of the project?

b. Alternatives considered. Give a brief presentation of localisation alternatives, including technical alternatives that have been discussed with regard to the project. If possible, give a brief description of any differences in infrastructure requirements etc.. The 0-alternative, that is the impacts of not implementing the project, may also be relevant to consider.

c. Description of the project and potential main alternatives. Give a relatively comprehensive description of the alternative(s) that are viewed as relevant. This description should include e.g. choice of technology, localisation of any facilities with relevant map references, transport needs, labour requirements and impacts on existing or planned activities in the area. This information should cover both the constructional and the operational phases.

d. Conditions for project implementation. Give an account of the public and private physical initiatives (infrastructure, etc.) and any other external prerequisites that are necessary for the implementation of the project e.g. participation of the local population, local institutional and administrative conditions, including their environmental competence.

2 Description of the environment

Give a brief description of the natural and man-made environment in which the project is to be located. This information should normally be included in the given project documents, but may also have to be supplemented through collection of information and consultations with relevant institutions, professional units, local populations, or short surveys in the project area.

Where appropriate the information should also be presented in thematical maps or illustrations. Sources as well as the reliability of the presented information should be indicated briefly. The description should contain an account of:

Natural environmental conditions:

· Geology and soil conditions.
· Hydrological and hydro-geological conditions.
· Topography.
· Climate.
· Vegetation and fauna, with emphasis on: particularly vulnerable ecosystems and vulnerable and conservation-worthy animal and plant species.
· Unique and conservation-worthy natural landscapes.

Man-made environmental conditions:

· Socio-economic and socio-cultural conditions.
· Demographic conditions,
- size of affected population groups, and - any ethnic belonging and variations.
· Health situation,
- with special emphasis on environmentally related diseases.
· Settlement pattern and means of production,
- specified for ethnic group, class or caste, and
- division of labour organised on the basis of gender and age within the population groups in question.
· Existing land use and utilisation of natural resources,
- also including more extensive utilisation of nature areas.
· Unique and conservation-worthy cultural landscapes or objects and buildings og historic, archeological, architectonic, cultural, aesthetic or scientific value.
· Existing environmental problems and environmental stress,
- for example current pollution of water and rate of soil erosion.
· Other existing or planned activities that may hold future consequences for the water supply, water quality, wastewater management or irrigation.

3 Checklist

The aspects included in the following checklist must be commented on. In case the problem is irrelevant, this must be substantiated. If the listed impacts can be expected to appear, their extent and degree should be estimated. Compare with Part I of this booklet if some questions should be unclear. One should be aware that questionaire checklists like these are not always 100% adequate with regard to all environmental questions which can be relevant to ask. It may therefore be useful to compare the use of the checklist to the use of other analytic tools for project assessment, e.g. logical framework analysis, gender analysis, assessments of socio-cultural and socio-economic conditions, as well as assessment of choice of technology and existing institutional conditions. This may also prove to be necessary to secure an integrated approach to the assessment of the project.

It is necessary to specify which groups of the population will be affected by the different types of direct or indirect environmental impacts. A rough division can be as follows:

· The project's target group. This is the group of the population which one expects will benefit directly from the project. This group may, however, also be subject to certain negative environmental impacts.

· The remaining local population. This group will not benefit from the project in any primary way, although both positive and negative consequences may be experienced.

· Resettled population groups. These are groups who either settle in the area or move away from it as a result of the project or the development initiated by it.

Within these three groups it may also be relevant to specify if the environmental impacts from the project can be related to specific parts of the population, such as low-income groups, indigenous groups etc., combined with a further specification of gender and age within these groups.

Will the project

1. Lead to excessive exploitation of water resources, e.g. the groundwater sources and surface water sources?

Water supply and irrigation:

· Is the project planned on the basis of adequate data on the volume and condition of the water resources? Has for instance a hydrological mapping of the area which describes the capacity of the groundwater aquifer and the depth of the groundwater table been implemented?

· Is it certain that the extraction rate of groundwater does not exceed the natural replenishment of the resource?

· Is there a risk that extraction of groundwater may lead to the intrusion of saltwater from a nearby coastline and thereby reduce the quality of water?

· Is the project area especially vulnerable to the impacts of a lowered groundwater table?

· Will extraction of water from surface sources, for instance a river, cause a reduced water flow downstream with impacts on the ecology and utilisation of the watercourse?

· Will extraction from surface sources cause reduced recharging of the groundwater in the area or in any other manner substantially affect the hydrological cycle?

· Are there existing or planned activities in the area/watershed area which may affect the water resources and thereby alter the preconditions for the project?

· Have the possibilities for re-circulation of water been investigated and assessed during the project planning?

2. Cause pollution problems?

Water supply:

· Will the wells be adequately secured so that these are not contaminated by people, animals, or activities in the area?

· Will periodic control of the water quality in the drinking water wells be implemented?

· Can the intended utilised groundwater source contain so much nitrate that it may be a health hazard?

· Is the groundwater acidic (low pH) thereby causing corrosion and destruction of water pumps?

· Are the intended utilised pumps dependent on grease for maintenance which may contaminate the drinking water?

· Will any use of chlorine as disinfectant be implemented cautiously?

· Will reduced water flow as a consequence of inundation or substantial extraction of water lead to reduced dilution of pollution in the river and thereby increase the pollution concentration?

· Will water extracted from surface sources be sufficiently purified in well-adapted purification units?

Wastewater management and sanitation:

· Will activities within wastewater management and re-circulation of wastewater be based on thorough assessment of the content of the wastewater, the recipient capacity to receive substances and, in the case of discharges to soil, the soil's capacity to filter substances?

· Will activities for discharge of wastewater to surface water sources be based on assessments of existing pollution?

· As regards discharge to lakes will consideration be given to the fact that these constitute part of a larger integrated run-off system which includes rivers, streams etc.?

· Will discharge of wastewater take place in estuaries?

· Is there a danger of contamination of groundwater sources from the surroundings, so that it may be relevant to secure or protect a certain area around the sources to limit the risk of pollution?

· Will smell or noise from treatment processes for wastewater and sludge deposition be a problem for the immediate environment?


· Is there a risk that irrigation through canal systems will spread pollution from agriculture (for instance residue of pesticides) and other activities?

· Will reduced water flow as an impact of dam construction or substantial extraction of water lead to less dilution of pollution in the river and thereby increased concentration of this pollution?

3. Cause health problems?

Water supply:

· Will due consideration be given in the planning and implementation of the project to health and hygiene to avoid increasing the frequency of disease? For instance will one establish separate training programs for health and hygiene, and implement regular maintenance of the facilities?

· Will water sources for the purposes of drinking and preparation of food be held separate from sources for other purposes?

· Will one, for instance through training, secure that the water is not polluted when it is fetched or afterwards?

· Will adequate drainage of well areas be secured to prevent water stagnation?

· Will enough water be secured for the purposes of washing of hands and body, laundry, or other washing?

· Is there a risk of urban water supply systems spreading diseases and causing epidemics due to inadequate purification units, poor maintenance etc.?

Wastewater management and sanitation:

Also confer with the checklist questions under 2 above.

· Will latrines be placed so that they cannot pollute drinking water sources?


· Is the risk for spread of water-related diseases assessed before implementation of the project?

· Will canals be located in the terrain so that one does not obtain passages with stagnant water? And will adequate maintenance be ensured to prevent the growth of plants in canals and ponds which make good habitats for f.ex. snails which transfer bilharzia?

· Will wastewater be utilised for irrigation? If so, is the wastewater properly purified prior to such utilisation?

· Will turbulence be created through the establishment of dams and/or sluices increasing the spread risk of river blindness?


· Is the risk for work-related accidents during the construction and operational phase reduced to a minimum?

4. Cause soil erosion?

Water supply and wastewater management:

· Can an area around water points suffer erosion due to strain on the vegetation cover caused by trampling of humans and animals and increased grazing?

· Will water and drain pipes located on the surface become physical barriers and cause changes in the transport or migration patterns for humans and animals, with subsequent erosion in new paths and transport routes?


· Is there a risk that irrigation canals can cause considerable erosion?

· Will adequate maintenance of canals and facilities be secured. And will a controlled management and distribution of the water resources in the irrigation system be implemented in order to avoid floods and subsequent erosion and destruction of facilities?

· Have assessments of the soil type been made in cases of drip irrigation to ensure that the soil is suited for this type of irrigation?

· Will new dams be constructed in areas especially vulnerable to erosion?


· Are there cases of soil erosion in the watershed area that may adversely impact the project by reducing the water quality, reduce the recharging of groundwater sources, cause siltage of dams etc.? If so, has the project taken this into consideration and planned/suggested erosion prevention measures in the watershed area?

5. Cause inundation of large areas through dam construction?

Water supply and irrigation:

· Will dams of such size be built that large areas containing settlements, agriculture, conservation-worthy fauna and flora, beautiful and valuable landscapes, and cultural relics will be covered by water?

· Will inundation cause substantial changes to the water flow downstream?

Confer initial assessment booklet 6. Hydropower development for a more thorough assessment of dam establishments.

6. Cause waterlogging, salinization or other damages to the soil?


· Have the contents and characteristics of the soil and water been assessed prior to implementation of the project?

· Will drainage canals be constructed with capacity to prevent the problems of waterlogging? And will they enable a thorough "cleansing" of the soil if salinization and alkalinization occurs?

· Will the management of the water resources in the irrigation system ensure the correct amount of water to the right time?

7. Affect vulnerable ecosystems or conservation worthy landscapes and cultural relics?

Water supply, wastewater management and irrigation:

Will the project affect ecosystems which are especially vulnerable to intrusions in the hydrological cycle; e.g. estuaries, wetlands, mangrove areas, delta areas, littoral zones and shore/bank areas?

· Will the project affect water resources or other landscape elements of special importance to the scenic value or affect the local population's sense of belonging to the area?

· Will the project affect cultural relics, burial sites, or places or objects of religious importance?

· Will special considerations be given to the design of facilities and installations to ensure an adaptation to the landscape?

8. Cause user conflicts or other impacts for the community?

Water supply and sanitation:

· Will the localisation of wells and water pumps be based on assessments of land tenure, ownership rights to water resources, and the role of women as regards water and water usage?

· Will adequate consideration be given to the population's wishes, any traditions, taboos and symbolic values connected to water and sanitation?

· Is there a risk that the water supply may cause an inadvertent migration to the area which may cause conflicts as regards the usage of water and other natural resources?

· Can the establishment of water supply for new activities in the area, for instance tourism, create conflicts with the existing water supply system through competition as regards the same resource?

· Is there a risk that increased competition as regards water resources indirectly forces certain population groups to move from the area to more vulnerable areas?

Wastewater management:

· Can conflicts as regards area utilisation ensue due to wastewater treatment ponds requiring relatively large areas?

· Can discharge of wastewater disturb other use of the water resource, for instance fishing, washing, bathing etc.?


· Will irrigation be introduced to an area where this previously has not been practiced?

· Is the project based on extensive migration to the area as part of a settlement project?

· Can an uncontrolled migration to the area be a consequence of the project?

· Will measures to reduce social unrest and conflicts between the residents and the immigrants be given consideration in the project?

· Irrigation farmers can f.ex. acquire some prestige compared to other farmers in the local community. Will the project take adequate consideration to traditions, power structures etc. in the area?

· Will the project, though it be new constructions or rehabilitation of existing irrigation facilities, adequately consider the role of the water management as regards productivity, damage to facilities and the emergence of negative environmental impacts?

· The construction of dams may force population groups to move from the area. Will the project ensure that conditions are made for a relocation of settlements with the least possible conflicts?

Confer also question 5 above as regards the construction of dams.


· Will the project adequately consider the development of institutions, water user organisations and other types of co-ordination between the local population (users: households, farmers, industry) and local and central authorities to achieve an environmentally sound management of the water resources?

· What are the possibilities for the project to become a part of an integrated water resources management plant?