Introduction

The River Rhine flows from the Swiss Alps through Germany, France and The Netherlands into the North Sea (Fig. 7.1). With a length of 1320 km, the River Rhine is the longest river in Western Europe with a total catchment area of about 185,000 km2. The catchment has a population of approximately 50 million.

Fig. 7.1. The Rhine Basin and its countries.

© CAB International 2004. Climate Change in Contrasting River Basins

Fig. 7.1. The Rhine Basin and its countries.

© CAB International 2004. Climate Change in Contrasting River Basins

As a result of industrial development and population growth, water demands increased for a large range of functions such as domestic water supply, industry, agriculture, hydropower generation, recreation, navigation and cooling purposes. In view of the functions and uses, the Rhine has undergone many modifications and has turned into a heavily engineered river. In the past the river was considered wild and it took more than 100 years to turn it into a navigable river, to canalize it, to equip it with power stations in the Alsace Plain and to make it the main water supply in the lower reaches. Worldwide, the Rhine is among the inland waterways with the highest traffic density, with the port of Rotterdam being the largest seaport and Duisburg one of the largest inland ports in the world (CHR, 1993).

Water use and agriculture in the Rhine Basin

Under present-day conditions, about half of the total area of the Rhine Basin is used for agriculture, approximately one-third is covered with forest, 11% is built-on area and the remainder consists of surface water. Agricultural land use is an important element in the rainfall-runoff relations in the Rhine Basin. Investments in land drainage, external water supply and large-scale use of biocides and fertilizers have increased agricultural production. Yet, at only 10% of total extraction, agricultural water use is relatively low compared to that in arid climates. In this context, Dutch water management practices use a large amount of Rhine water to maintain a constant (ground) water level in the polders and low-lying areas of the delta in the summer.

Another important water use is navigation, which requires minimum water depths and is limited by maximum flow velocities. Hence, the Rhine, its tributaries and branches have been partially canalized and divided into sectors, separated by locks. Use of Rhine water for human consumption varies between 5% and 15% of the mean annual discharge. This may not seem much, but consumption is not spread evenly over the year: the demand is greatest in summer, when the mean discharge is lowest. This means that the available water must be carefully apportioned during dry summers (Speafico and Kienholz, 1996; RIZA, 2000).

About 20 million people depend on Rhine water as a source of drinking water (Dieperink, 1997). Most of them live in Germany and in The Netherlands. In the western part of The Netherlands, groundwater is often too brackish to be used as drinking water.

Threats to the water resources system

In recent years (1988, 1993, 1995 and 1998) peak flows and even small flood events caused substantial socio-economic problems, especially in the lower parts of Germany and The Netherlands. The encroachment of urban and industrial expansions along the river, together with agricultural developments, makes it impossible for the river to inundate the original valley. Approximately 85% of the floodplains have been withdrawn from the natural river. Hence the risk of flooding has increased, especially in downstream areas.

The Rhine has been subjected to enormous amounts of pollutants over a long period of time. Pollution reached its maximum between 1960 and 1975, when the Rhine was described as an open sewer. In particular, high loads of organic waste (sewage) resulted in oxygen levels too low for many fish species. The Rhine became a dead river, losing its function as provider of drinking water and depositing large amounts of polluted sediments in the river's tidal areas and on its floodplains. The situation improved significantly due to the installation of water treatment works by industries and cities during the 1970s and 1980s. However, accidents can still take their toll. A fire at Sandoz Chemical Industry in Basel, Switzerland, in 1986 led to severe pollution of the Rhine, resulting in massive death of macrofauna and fish.

The different water demands and uses often compete and impose stress on the water resource system in terms of human security and nature values. Increasing demands have led to a range of measures to control water resources. Specific measures concern drinking water supply and water pollution control, flood protection, energy production, navigation and more recently the ecological rehabilitation of the river. The relatively large number of countries, however, makes it difficulty to develop a common vision to cope with developments that may impact the trans-boundary water resources system of the basin. The pollution events of the 1970s and 1980s gave an impulse to the already existing International Commission for the Protection of the Rhine (IPCR), which has the commitment of all the important tributary countries. This Commission prepares plans for further improvement of the water and ecological quality of the river. It developed the Rhine Action Programme, which has a reduction of (sediment) pollution as one of its key objectives, and 'Rhine 2020', which focuses on flood protection.

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