At first glance, Swiss water protection might be seen as a success story. However, a differentiated analysis of the situation reveals substantial deficits in the management of our water bodies. Major efforts are still needed with regard to the structure of streams and rivers as well as water quality in order to maximise diversity. Only then will this habitat, which is crucial for biodiversity in Switzerland, be able to meet the future challenges of climate change.
- 1. Energy production, agriculture, settlement growth, consumption, climate change (drivers)
- 2. River engineering, alteration of the water flow regime, input of nutrients and pollutants (pressures)
- 3. Micropollutants and nitrate in ground and surface waters, temperature increases, impairment of the structure of surface waters and flow rates, insufficient habitat quality (state)
- 4. Impaired habitats and the animal and plant world, flooding, groundwater pollution, drinking water production (impacts)
- 5. Restoration, regulations on protection and use, wastewater treatment (responses)
1. Energy production, agriculture, settlement growth, consumption, climate change (drivers)
Water bodies and water resources are used intensively by society and the economy in a wide variety of ways:
- for the production of drinking and process water,
- for energy production,
- as a place for leisure and recreation,
- and for wastewater disposal.
Settlement growth, intensive agriculture and the expansion of hydroelectric power increase the pressure on water bodies and affect water quality.
Climate change alters the temporal and spatial availability of water and increases the temperature of water bodies. When this is combined with more intensive use, conflicts of interest increasingly become an issue.
Water resources are coming under increasing pressure not just in Switzerland but also worldwide, with international competition for water increasing.
2. River engineering, alteration of the water flow regime, input of nutrients and pollutants (pressures)
As a reservoir for Europe, Switzerland has vast water resources. Despite the increase in population, water consumption by households, industry and commerce has declined since 1975. However, irrigation requirements are increasing as a result of climate change.
Intensive agriculture and the needs of society put pressure on the quality of groundwater and surface waters. Water quality is impaired by residues of fertilisers, plant protection products and components of personal care and cleaning products and drugs. Undesired substances also reach the water from roads and sealed surfaces. Even in very low concentrations, these micropollutants can have negative effects on water quality.
Intensive land use in the past resulted in the large-scale alteration of the structure of surface waters and the impoverishment of the landscape. Numerous watercourses accommodate engineering structures or have been straightened to provide for increasing land needs or to provide flood protection for settlements. Hence, the space originally available to watercourses has been limited to a single channel in many places.
Growth in settlement areas and the expansion of transport infrastructures put groundwater protection zones under increasing pressure. The open spaces around drinking water catchment areas are being increasingly used or built on and are no longer able to fulfil their protective function. This also means that the Waters Protection Act is not being implemented consistently enough with regard to groundwater protection. As a result, drinking water supplies sometimes have to be closed.
Hydropower production influences water volume and causes structural changes in the water bodies. Sufficient residual flow is necessary everywhere for watercourses to be able to sustainably fulfil their function as a habitat and a migration corridor for aquatic organisms. Around 25% of the 980 water withdrawal points that require remediation and were supposed to have been remediated by 2012 have still not been remediated.
During peak energy production, storage power plants generate fluctuations in downstream watercourses (hydropeaking). As a result, the water level, the flow rate and the river width are subject to very sudden changes. By 2030, free fish migration must be restored at about 1,000 hydropower plants across Switzerland. Moreover, 100 hydropower plants that cause hydropeaking must be remediated, in addition to 500 hydropower plants and other installations that cause bedload deficits.
3. Micropollutants and nitrate in ground and surface waters, temperature increases, impairment of the structure of surface waters and flow rates, insufficient habitat quality (state)
With regard to nutrient pollution, the water quality of surface water bodies has improved significantly since the 1960s. However, despite substantial progress, the state of many surface waters is still inadequate. Small water bodies are heavily polluted by nutrients and plant protection products from agriculture, while medium-sized and large water bodies contain micropollutants from households and industry as well.
The state of groundwater in Switzerland is still good enough to be able to obtain sufficient quantities of clean drinking water from groundwater sources. However, pollutants have been recorded in the groundwater at numerous monitoring stations of the National Groundwater Quality Monitoring Network (NAQUA), especially in intensively farmed regions. Groundwater is most severely affected by nitrate. Furthermore, residues of artificial, sometimes persistent, substances such as substances from the degradation of plant protection products have been detected in the groundwater at more than half the NAQUA monitoring stations. Even though these substances are largely within the limits of the Waters Protection Ordinance (WPO), they are generally undesirable in groundwater. Moreover, long dry spells can cause groundwater levels to fall temporarily.
The temperature of the Rhine near Basel has increased by over 2°C since the 1960s. Climate change and the discharge of heated water, for example from cooling plants and wastewater treatment plants, contribute to this development. Similar temperature increases can also be observed in other water bodies in the Central Plateau.
Climate change also influences the volume of water in watercourses: the water flow regime in non-glaciated catchment areas tends to increase in winter and decrease in summer. Pronounced low-water periods in summer can be expected more often in the future. Since a warmer atmosphere can hold more water, more frequent heavy precipitation can be expected, which can cause flooding.
Switzerland’s hydrological network comprises approximately 65,300km of rivers and streams.
- Today, 14,000km or 22% of the hydrological network have been significantly altered through structural interventions, for example, walls, artificial drops and bank reinforcement structures or culverted. In the Alpine valleys, as much as 52% of the entire network of watercourses at altitudes of less than 600 metres above sea level is in a poor ecomorphological state.
- 10,800km of watercourses range between significantly impaired and unnatural and require remediation. Watercourses in intensively farmed and low-lying areas are particularly severely impaired.
- Thanks to the remediation of increasing stretches of watercourses since the late 1980s, a slight increase in the number of near-natural rivers and streams can be observed.
- Alpine rivers downstream of storage power plants are particularly affected by changing flow rates (hydropeaking - surge and low flow) up to their points of entry into the pre-Alpine lakes.
- According to studies, the natural bed load regime in approximately 41% of surveyed watercourses (totalling 1,900km) is severely impaired.
Many, especially small, Swiss watercourses are in a biologically unsatisfactory state. For plants and invertebrates, the habitat quality is unsatisfactory at one-third of the monitoring sites; For fish, which have greater demands on the habitat, two-thirds of the sites are classified as inadequate. The reasons for this are deficient water body structures and frequently inadequate water quality.
Indicator Phosphorus concentration in lakes
Indicator Nitrate in groundwater
Indicator VOC in groundwater
Indicator Groundwater levels and spring discharge rates
Indicator Groundwater temperature
Indicator Temperature of watercourses
Indicator Low-flow events
Indicator Flood events
Indicator Biological status of surface waters
Indicator Structure of watercourses
Indicator Bathing water quality
4. Impaired habitats and the animal and plant world, flooding, groundwater pollution, drinking water production (impacts)
The water temperature is one of the most important regulators of life processes in surface waters. Aquatic organisms react sensitively to increases in temperature: for example, water temperatures of 18-20°C can trigger the development of stress symptoms in trout, whitefish and grayling. Temperatures in excess of 25°C can be fatal.
Micropollutants have negative impacts on aquatic ecosystems, even in very low concentrations. For example, endocrine disruptors can damage the hormonal systems of aquatic organisms and hence impair their fertility.
Changes in the structure of watercourses affect the plant and animal world: engineered watercourses lack the habitats necessary for the aquatic organisms (e.g. gravel banks, alternating areas of deep and shallow water, periodically flooded areas). Artificial obstacles create migration barriers for fish and other aquatic animals.
The substantial deterioration of water bodies and wetlands is reflected in the Red Lists of endangered species. More than one-fifth of the species that are threatened by extinction or are already extinct in Switzerland are linked to water bodies, and another fifth to shores and wetlands. Strongly fluctuating water volumes (hydropeaking) pose a threat to aquatic animals: when the water level surges, they are swept away, and during low flow, they risk being stranded on banks.
During floods, engineered watercourses lack space to accommodate the flood water and extensive flood damage can arise as a result.
Over 80% of the drinking water in Switzerland is sourced from groundwater. Approximately 40% of groundwater can be fed directly into the drinking water supply system without being treated, and a further 30% is treated with disinfectants as a precaution. However, the presence of residues from fertilisers and plant protection products in groundwater and the increasing development of groundwater protection zones are putting drinking water resources under considerable pressure in some regions. As a result of climate change, shortages in supply and, hence, conflicts between drinking water and other water uses (e.g. agricultural irrigation) could arise, in particular during periods of drought.
5. Restoration, regulations on protection and use, wastewater treatment (responses)
Switzerland has a good legislative basis for the protection of groundwater and surface water bodies in the Waters Protection Act and the associated ordinance. In order to restore their natural functions and strengthen the social benefits they provide, the remediation of rivers and lakes has been required under the provision of the Act since 1.1.2011.
In addition, the cantons must designate a minimum area for surface water bodies. Agricultural areas located within the surface water areas must be managed as ecological compensation areas. CHF 20 million has been added to the agricultural budget for this purpose. Around CHF 30-40 million per year is allocated to remediation measures. The cantons completed their strategic planning for these measures by the end of 2014. The first projects are already being implemented.
The negative impacts of hydropower production, e.g. hydropeaking (surge and low flow), must also be eliminated and fish migration must be ensured by 2030. CHF 50 million has been made available annually for this purpose (generated by the imposition of a surcharge on the transmission costs for high-voltage networks).
Thanks to the construction of the wastewater treatment plants (WTP), it was possible to achieve significant improvements in water quality from the 1960s. Around 1,500 million cubic metres of wastewater undergo appropriate treatment annually in the WTPs.
The problem of inputs of micropollutants into water bodies has been acknowledged. The implementation of micropollutant elimination measures began in 2016. According to the criteria established in the Waters Protection Ordinance, the cantons determine which wastewater treatment plants (WTPs) are to be expanded and then carry out the measures. If an additional treatment phase is added to around 100 specially selected WTPs in future, micropollutants can be removed from almost two thirds of all wastewater. The necessary investments are financed by a Switzerland-wide wastewater charge.
To reduce the inputs of plant protection products in water bodies, especially from agriculture, the Federal Council adopted an Action Plan on Risk Reduction and Sustainable Use of Plant Protection Products. It sets measurable goals and specifies concrete measures.
To counter the effects of climate-induced changes in the water cycle and prevent conflicts over utilisation, changes in water management are needed. The federal government is developing further scientific bases (e.g. climate change impact modelling) and provides practical measures for tackling water shortage problems.
The federal government works together with the riparian nations of transboundary water bodies on programmes for cross-sectoral water management in international catchment areas, such as “Rhine 2020”. Switzerland supports EU member states in implementing the European Water Framework Directive in accordance with international treaties and their national legislation.
Hydrological Yearbook of Switzerland 2021 (Summary)
Zustand der Schweizer Fliessgewässer
Coordinated biological surveys on the High Rhine and Aare 2001 to 2013 (Summary)
Mikroverunreinigungen in Fliessgewässern aus diffusen Einträgen
Last modification 20.12.2022