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1.1 General
1.2 Definitions and principles of water framework planning
2. Environmental impacts and protective measures
3. Notes on the analysis and evaluation of environmental impacts
3.1 Interrelated aspects
3.2 Analysis of use and quality of natural water resources
3.2.1 Determination of natural water supply
3.2.2 Determination of usable water supply
3.2.3 Determination of water demand
3.2.4 Hydrological balance and general planning
3.3 Analysis of effect on ecosystem, natural resources and resource utilisation
3.4 Analysis of effect on health and hygiene
3.5 Socio-economic and socio-cultural impact
3.6 Administrative and political framework
4. Interaction with other sectors
5. Summary assessment of environmental relevance
1.1 General
Water occurs as surface water and groundwater and is regarded as a renewable resource. The water supply of a region is normally limited. Quantitative renewal through the hydrological cycle depends essentially on rainfall, with wide quantitative and periodic variations as well as considerable regional differences.
The water supply rarely meets demand in terms of quantitative, periodic and geographical distribution, or in terms of water quality. This calls for controlling measures, i.e. targeted water resources management. Water resources management therefore signifies the regulation of all human uses of, and effects on, surface water and groundwater, thereby necessitating the development of objectives and general conditions covering all sectors for the utilisation of water resources by competing users, guaranteeing the environmental compatibility of water resources management activities.
Over-use, changes in land-use, climatic shifts etc. may in the long term impair the capacity for renewal, thereby reducing water supplies and their use.
A distinction should be made between those uses which do not involve actual water consumption (e.g. water used for cooling purposes) and those in which water is wholly or partially consumed or contaminated. Measures to protect against the damaging effects of water (e.g. flood protection) should be regarded as uses.
Peripheral conditions of water resources management are determined not only by technical and economic considerations but also by sociological, socio-cultural, legal, medical/hygienic and political aspects.
Water resources management is a vital tool of infrastructure policy and is particularly important for
- safeguarding the basis of life in rural and urban areas of habitation, through the provision of an adequate supply of safe drinking water
- improving hygiene in rural and urban areas of habitation, through controlled removal of sewage and waste, with measures to check the spread of water-borne diseases where necessary
- increasing agricultural production through soil improvement, irrigation and drainage
- promoting industrial production through the supply of potable and industrial water
- developing the transport system through the development of shipping routes on rivers, canals and lakes
- improving energy supply through development of hydroelectric power and supply of cooling water for thermal power stations
- extracting mineral resources through regulated pumping and discharge of groundwater (mine drainage water)
- protecting and preserving natural habitats by satisfying ecological water demand and measures to protect areas of water
- developing aquaculture by safeguarding natural and artificial habitats for aquatic organisms
- safeguarding habitats and agricultural and industrial production sites through measures to protect against flood and, where applicable, erosion, desiccation and desertification
- reducing the workload of women through targeted water provision
- developing tourism by safeguarding recreational areas on rivers, lakes and coasts.
In certain cases, these activities may be in competition with one another.
1.2 Definitions and principles of water framework planning
According to the relevant German guideline (16), the General Water Resources Management Plan embodies interrelated aspects and dependencies of the water resources management system within a planning area. It should set out water resource conditions in this planning area and allow an assessment of the likely effects of changes.
General Water Resources Management Plans are normally drawn up for natural geographical units, i.e. river basins or parts thereof. The area limits are the overground watersheds. General Water Resources Management Plans for economic areas or parts of economic areas should if possible be developed on the basis of general plans for the relevant river basins.
For the planning area it is necessary to clarify at the different levels (local, regional, national) when, where and how much water is available or needs to be provided, and where applicable in what quality, and what water resources management activities are necessary to balance supply and demand. These measures should be examined in terms of their financial, economic and ecological viability. In this process it is necessary to take account of current and foreseeable future general conditions within the planning area and within the overall natural geographical unit (e.g. river catchment area). Planning horizons are normally between 10 and 30 years.
A General Water Resources Management Plan summarises statements on
- current and foreseeable water demand
- possible ways of meeting water demand out of the water supply in the form of hydrological balances
- hydrogeological conditions in the planning area
- current and future occurrence and availability of water in terms of quantity and quality and periodic and geographical fluctuations
- possible ways of developing usable supply (formation of new supply, regenerative capacity)
- drainage control and flood protection (flood risks, high-water peaks, flood plains)
- maintenance of water purity (burden imposed by outfalls, self-cleaning properties)
- potential risks for surface water or groundwater due to existing or future uses (accidents, unsafe transportation of harmful substances, improper storage of refuse, commercial and industrial waste, discharge of agricultural pollutants such as fertilisers and pesticides)
- need for regulations covering those who discharge contaminants (quantities, quality, degree of pretreatment).
It is necessary to examine not only standard circumstances but also critical circumstances and periods, which are particularly important for correct design of water management schemes. Investigations must be carried out to see which bodies of water and which hydrologically important areas and regions require precautionary safeguards.
A General Water Resources Management Plan does not provide planning data and dimensional values for specific individual projects. Rather, it provides a basis for defining general conditions applicable to large areas for overall infrastructural development, e.g.:
- housing policy (urban and regional planning, rural development)
- location issues for the development of trade and industry
- conservation areas (flood plains, erosion protection, groundwater protection, with resettlement measures where necessary)
- statutory safeguards and conservation measures
- conditions governing emergency water supplies.
A General Water Resources Management Plan does however embrace the applicable general conditions of water management, and incorporates relevant measures. Only in this way can appropriate solutions be found and the important goal of regionally and socially fair distribution of water be achieved.
The General Water Resources Management Plan is a governmental (i.e. state) function which in Germany is performed at a number of levels:
- ministry, highest water authority
- water management administration (relevant offices, hydro-meteorological, hydrometric and hydro-geological departments)
- independent administrations (associations, user groups, cooperatives, traditional structures at target-group level).
To establish priorities for the utilisation and protection of water resources and keep the General Water Resources Management Plan permanently updated it is necessary to have a suitable legal framework and a properly functioning administration with the requisite powers and technical expertise; this includes the ability to resolve international problems.
2. Environmental impacts and protective measures
Very often the impact of an individual project, such as a small dam or the diversion of a small part of the runoff, is minimal and is limited to the local area, making a quantitative assessment of the impact difficult. If a number of projects are combined, such as chains of dams on a river course, or if the entire discharge is diverted, the effects may be serious.
Regulatory water management activities and the impact which they have essentially relate to:
- the damming and diversion of surface water (dams, reservoirs, small barrages, diversion works, pumping stations, open channels, pipelines) for the purpose of discharge regulation, flood protection, supply of drinking water and industrial water, hydroelectric power generation etc.); activities often serve a number of purposes at once (e.g. multi-purpose reservoirs), which means that many different aspects have to be coordinated within a complex framework;
- extraction of groundwater (dug wells, bore wells, spring water chambers), preferably for supplying drinking water and irrigation water; if these facilities are not properly designed, there is a high risk of contamination both of water drawn and of underground water stocks;
- transportation from the place of extraction to the place of consumption (portable vessels, open channels, pipelines); there is a high risk of contamination with all open and accessible systems;
- collection and utilisation of rainfall (cisterns, "rainwater harvesting"); over-use of this naturally limited supply is largely ruled out.
Water stocks can be adversely affected both in terms of quantity, i.e. in their quantitative, geographical and periodic availability (over-use), and in terms of their quality (pollutants).
In the case of surface waters, a change in runoff conditions means changes of flow cross-section, head, roughness and runoff rates. Changed flow behaviour causes changes to erosion and sedimentation processes. Damming can reduce high-water peaks, but also causes flooding of ecologically valuable areas, forces resettlement, creates stillwater zones and interferes with the habitats of aquatic flora and fauna, particularly migration conditions for fish. In addition, water that is accessible to humans and animals promotes the spread of water-borne diseases (malaria, bilharzia, parasitic diseases and dysentery).
The large number of hydrological and hydraulic variables alone necessitates the provision of a reliable database, backed up by long-term observations. Flawed planning assumptions, e.g. of possible flood discharges, causing dam failure or incorrect operation of barrages, can cause excessive flooding, resulting in serious damage.
In the case of groundwater, over-use may be caused by wells that are situated too close together or where drawdowns overlap, causing progressive lowering of the water table. Formation of new water reserves can be adversely affected by changes in land-use. Discharges of pollutants, be they intermittent (accidents, improper storage of waste, well contamination) or widespread (agricultural fertilisers and pesticides, large-area disinfestation of locusts etc.), may impair groundwater quality.
Long-term lowering of the water table over large areas may be necessary in the case of land used for agricultural purposes in order to prevent saturation and salination. However, in most cases this is harmful to natural vegetation and crops which then increase water demand because of the irrigation required and may intensify existing over-use.
Connate groundwater is a non-renewable water resource and therefore should not be exploited if at all possible.
Improved water resources management frequently generates secondary and tertiary effects such as an increase in demand (increase in per capita consumption of drinking water, increase in livestock numbers, expansion of agricultural irrigation) with further effects on the ecological and social framework for example (destruction of vegetation and soil through over-grazing and trampling by livestock, deforestation to create farming land, intensification of erosion by water and wind, conversion of nomads to a settled form of existence, concentration of habitation in well-supplied areas, closer contact and also conflicts of interest between different ethnic groups).
Often the situation arises where urgent environmental problems can only be resolved by considering other regions in a national analysis (otherwise, for example, building flood defences may expose those living downstream to greater risk of flood).
A General Water Resources Management Plan should contribute to the sustainability of water management projects through a long-term, multi-sector and large-area approach, preserving natural water resources and ensuring maximum environmental compatibility.
An essential conservation element in a General Water Resources Management Plan involves early consideration of the environmental effects of water management activities for the following reasons:
- Development planning and social priorities and likely effects of water management activities should be compared and evaluated; different activities or activities planned for different social groups and decisions should be made transparent by setting out the costs and benefits (the involvement of the population groups affected is extremely important); this will enable alternative solutions to be developed at an early stage;
- Preventive environmental protection i.e. the avoidance or minimisation of environmental problems in advance is generally far more effective and economical than corrective environmental protection, i.e. a subsequent clean-up or "rehabilitation" of polluted and partially destroyed environments afterwards.
A General Water Resources Management Plan provides planners with a tool whereby negative environmental effects and flawed developments can be avoided or at least alleviated, and requisite counter-measures or compensatory measures can be envisaged.
Depending on geo-ecological conditions and utilisation of the natural geographical unit, water management activities may, for example, affect the following:
- the climate (e.g. air temperature, air humidity, evaporation, radiation and heat),
- the quantity of available groundwater and surface water (acceleration of drainage through flood control, drainage retardation, infiltration),
- the quality of the groundwater and surface water (dilution, reduction or concentration of pollutants),
- soil quality and the area usable for agricultural and forestry purposes (groundwater level, soil degradation, erosion, sedimentation),
- habitats for terrestrial and aquatic flora and fauna (alteration and intersection of habitats, marshes, swamps),
- health and hygiene (living conditions for pathogenic organisms, drainage and sewage).
Measures to prevent negative environmental effects in the various areas of use (e.g. agriculture, industry) must be set forth in the General Water Resources Management Plan, but they must be tackled in the individual sectors.