the year 2000. These requirements do not include those of publicly-owned electric power plants nor the recirculated water requirements of industry, Bundesminister des Innern (1972).
develop in the future, the cause is either that.the natural distribution of the water res- ources is locally inadequate (possibly temporary) or that the water resources no longer satisfy quality requirements.
on a regional level. Two possible forms of management used in the FRG are:
Where regional problems in meeting water requirements already exist or are likely to These problems can be solved by management of water resources (i) water transfer from one catchment area to another
(ii) regulating reservoirs
Problems due to inadequate water resources are arising in almost all of the metropoli- tan areas of the FRG shown on Figure 4, including the Bremen area, the Ruhr industrial dis- trict, the Rhine-Maine area, the Rhine-Neckar area of Stuttgart-Karlsruhe-Mannheim and the NÜrnberg-Fürth-Erlangen area. All these regions either have adequate water as a result of specific measures of water resource management, or plans have been made for an adequate supply of water in the future. For example, river management initiated at the turn of this century has supplied additional water to the North-rhine-Westfalen industrial complex (the Ruhr district) from a system of reservoirs located in the neighbouring Sauerland mountains.
The required water flows from these reservoirs via the River Ruhr to the metropolitan area and is used primarily to ensure the supply of potable water. The discharge of water from this reservoir system is controlled so that the River Ruhr has a constant flow rate of 20 m3/sec in the Ruhr District.
water supply its effluent load is kept down so that the resulting cost for processing the potable water is very low. The very large quantities of effluent produced in the metropoli- tan area are discharged into the Emscher River which runs to the north of the Ruhr. In order to prevent any additional effluent load on the Rhine due to the great quantities of waste water carried by the Emscher, a large-scale treatment plant has been built just up- stream of the confluence of the Emscher and the Rhine. When the last phase of this plant has been built, it will be capable of treating 20 m3/sec.
this area has an adequate supply of water from the Weser River, its quality is extremely poor due to a high degree of contamination and to salinity; thus the cost of processing would be high. To reduce this processing cost and to improve the quality of the potable water, part of the water supply is obtained from reservoirs in the Harz mountains via a pipe- line system 250 km long.
The transfer of major quantities of water in the form of a 'moving wave' (Ruhr District) or pipeline system (Bremen) will cause a corresponding effluent movement in the area being supplied. These increased quantities of effluent cause an additional load for the natural receiving waters. Thus, the conurbation of Central Wurttemberg
-
especially the Stuttgart area-
is supplied primarily from the Danube lowlands and from Lake Constance, with a total of 5.5 m3/sec of potable water, via a long-distance pipeline system.potable water will have increased to 12.8 m3/sec (Bundesminister des Innern, 1971). The constantly increasing amount of effluent discharged into the Neckar River will create an urgent need for improvement of its low water flow rate. Even if all potential effluent treatment measures are exploited, the river's flow rate will need to be increased by 20 m3/
sec in the near future. The construction of several reservoirs (with a total capacity of 200 million m3) in the upper reaches of the Neckar River is being considered for this pur- pose.
Water transfer from one catchment to another is accomplished by a variety of techniques in the FRG, depending on the type of exploitation in the area being supplied. Whereas the Stuttgart and Bremen conurbations are supplied with potable water from remote watersheds via pipeline systems, a supply of industrial water or an input of water to improve the low flow rate of a river cannot be accomplished via a pipeline system because this would be too expen- sive in view of the quantities of water to be moved. Thus, it is intended to use the proj- ected Main-Danube canal to move 15 m3/sec from the Danube to the Regnitz-Pegnitz-Main water- shed, ie to the Nurnberg-Furth-Erlangen conurbation, in order to increase the low flow rate of these rivers. At the same time this water management measure is intended to provide new impetus to the industrial and trade development of this area.
Because the Ruhr water is used primarily for a potable
A different type of water supply system is used in the Bremen metropolitan area. While
By 1990 this influx of
52
Projected impact
of
community scale urban olater conservation measures11-1.5.2 'Sealing' the surface
The area occupied by housing, industry and transport in the FRG is continually increasing.
Thus, in 1970 as much as 10% of the total territory of the FRG was built-up, 50% more than in 1938. Until 1.980 an annual loss in the order of 45 O00 hectares of agricultural and forestry area for construction purposes is likely. This continual increase in the use of open areas for construction purposes causes a reduction of the pervious area in the affected regions. As a result of this artificial 'sealing' of the surface, precipitation will run off more quickly on the surface, and canalisation of natural stream courses wil1,accelerate this effect. Especially where separate foul and storm sewers are used, surface runoff is moved to the nearest water course via the shortest route possible. As a result of this develop- ment, flood waves in the rivers will be more frequent and will be steeper, while low flows will reduce and last longer. Depending on local conditions, severe lowering of the ground- water table may occur, so that public water supply systems which obtain potable and indus- trial water from these groundwater resources are forced to satisfy their water requirements from other sources.
Contamination of groundwater by effluent draining from unsafe sewage systems occurs in almost all urban and industrial districts of the FRG. Groundwater used for water supply must be protected against such harmful effects to safeguard the public water supply; the Water Acts afford a legal tool for this purpose.
11-1.6 PROJECTED IMPACT OF COMMUNITY-SCALE URBAN WATER CONSERVATION MEASURES
The German towns in the coastal area of the North Sea can be supplied with local alluvial groundwater, which is sufficiently recharged by precipitation to prevent drawdown problems.
There are no problems of saline intrusion into the groundwater reservoirs.
Desalination of seawater is not yet used in Germany, and those coastal islands which have insufficient natural freshwater are supplied with extra water via pipelines from the mainland.
water using sprinkling. This type of effluent disposal has declined in use during recent years for health reasons, and it has not been practised where the groundwater is used for any purpose requiring drinking water quality.
ment Law requires water protection areas to be defined and established. This became necess- ary because industrial, housing, and roads are claiming more and more land. The definition and establishment of water protection areas is supervised by the water authorities of the states, and each area is subdivided into 3 zones, each zone depending on the degree of dan- ger to the water supply.
Difficulties in protecting water supplies in urban conurbations against pollution will lead in the future to the closing down of smaller water treatment plants and the creation of larger ones giving better protection; however, water transportation over longer distances will be the price paid for such changes.
In some parts of the FRG, pretreated effluent has been removed by percolation to ground-
To protect the groundwater reservoirs of the FRG against pollution, the Water Manage-
11-1.7 WATER SUPPLY EFFECTS
The mean annual precipitation for the FRG is approximately 200 O00 million m 3 . After deduc- tion of all losses, the remaining resource is 16 O00 million m3 of groundwater and 30 O00 million m3 of surface water, ie a total of 46 O00 million m3 which can be used;
not poor in water resources.
zation during the cycling of river water, potable and industrial water, and wastewater.
Table reflects the water requirements in the FRG, (Batelle-Institut e.V., 1972).
arately because engineering developments, particularly in coaling techniques, are difficult to predict.
the FRG is The useful quantity of water available can be increased as a result of multiple utili- The cooling water requirement of electric power plants for a public supply is given sep-
Water
;upnZy
effectsTable 9. Water requirements in the FRG, in 1000-million m3
User 1969 1975 1980 1985 2000
According to Table 9 , the water requirement of industry has the greatest growth rate, some 2.3% per annum on average.
ment will have doubled, rising from about 11 O00 million m3 in 1969 to 22 O00 million m3 by the year 2000. As a proportion of the total water requirement, the industrial share will rise from 39.6% in 1969 to 50.3% in the year 2000. The largest user of industrial water is the chemical industry, and its share of the total water requirement rose from 28.8% in 1959 to 35.8% in 1969; estimates suggest that it will be 54.9% by the year 2000.
sources, one-third being from groundwater and spring water while two-thirds was from sur-
face water. this percentage does
however represent one quarter of the total public supply.
Subdividing the industrial water requirement according to use shows that the greatest increase in demand will be for cooling water, rising from 7 800 million m3 in 1969 to 16 700 million rr3 in the year 2000. The expected rise in the cooling water requirement of public electric power plants is from 12 400 million m3 in 1969 to 15 900 million m3 in the year 2000. Thus, the greatest use of water by industry and in public electric power plants is for cooling purposes.
power plants. The specific cooling water use for non-recirculating cooling systems is 150 litres/kWh, and 80 litres/kWh for recirculating cooling systems. The cooling water required by a recirculating cooling system to produce one kilowatt hour is therefore slightly more than half that required by a non-recirculating system. However, the capital cost of recir- culating cooling systems is considerably greater than that of non-recirculating systems. In 1969 a total of 12 000 million m3 of water was used for non-recirculating systems, compared with 4 400 million m3 for recirculating systems.
in 1969 was produced with recirculating systems, and this percentage is expected to rise by 50% by the year 2000 because of the limited water resources available for cooling purposes.
Consequently, by the year 2000 the industrial water require-
In 1969, 93% of the industrial water requirement was met from privately financed The remaining 7% was provided by public water supplies;
Data or predictions for different types of cooling systems are available for public
Approximately 40% of the power generated The water required for irrigation in agriculture will not change significantly.
Domestic requirements from the public water supply are expected to rise from 2 600 million m3 in 1969 to 4 700 million m3 in the year 2000.
steadily increasing demands for personal comfort by the population. In terms of consumption per inhabitant, the requirement is expected to rise from 118 litres per inhabitant per day
in 1969 to a level of 204 litres per inhabitant per day in the year 2000.
and 40% from surface water resources. Because most of the high-quality groundwater resources are already being used for water supply, groundwater resources of a lower quality together with surface water resources must be developed to meet the continually increasing water
requirement. Thus, in Northrhine-Westphalia, the region with the greatest population density, already about two-thirds of the water requirements are met by surface water, and only one- third from groundwater.
ed from the same sources in the year 2000 as today, some 14 O00 million m3 of water would be required from groundwater sources.
This increase is due in part to
Today, about 60% of the water requirements in the FRG is met from groundwater resources
On the assumption that the water supply for domestic and industrial use was to be obtain- This would mean that the annual groundwater recharge of
54