Photo: BMLFUW/Rita Newman
Running waters – Rivers and brooks
Waterways are and always have been vital arteries of human settlement and economic activities in the country. “Proximity to waterways”, so often sought by people for transport, nourishment, etc., can also conceal hazards (e.g. due to flooding).
Which impacts can human utilisations have on running waters?Buildings and water abstractions to utilise water energy, the settlement of areas close to rivers and protective structures for flood control as well as the intensive utilisation of valleys for agricultural purposes have clear effects on brooks and rivers:
- Infrastructure, residential areas and traffic routes restrict the “living environment” water and are at risk
in cases of flood.
- Transverse structures, e.g. dams, interrupt the passability of rivers.
- In retaining spaces above retaining walls the flowing velocity is reduced, sludge deposits more easily, the
habitats of the animals living in those waters impoverish.
- The straightening and damming of the rivers lead to separation from side waters and monotonous water
structures.
- Excessive water abstractions at power stations deprive aquatics of their basis of life; water jump can
cause extreme water level variations and rinsing effects.
- Erosion and the washing away of nutrients from agriculture entail disturbances in the ecological balance
of waters.
All those impacts can significantly reduce the habitats and the species diversity of running waters, which is of importance in particular to the dwindling of many fish species. However, these interventions influence not only flora and fauna, but also the landscape we live in.
Again and again lakes and running waters have been contaminated by wastewaters. As nowadays most households and enterprises are connected to the public sewage networks and wastewaters are no longer directly introduced into waters, there are but few problems in this field at the moment and the quality of the water is for the most part excellent again.
Rivers and groundwater
Rivers and groundwater do not know any boundaries, they mutually influence each other. Any impact on a river in its upper reaches will influence its lower reaches and the people, animals and plants living there. For this reason the entire catchment area of a river, including its groundwater, is considered and managed.
A river catchment area comprises a river from its spring to the estuary mouth. It includes also all tributary brooks as well as the groundwaters of the region.
Austria has a share in three international river catchment areas: Danube, Rhine and Elbe. 96 percent of our federal territory are located in the catchment area of the Danube. Totally, 10 percent of the European territory are located in the River Danube’s catchment area. To allow detailed handling, the Austrian river catchment area of the Danube has been further subdivided into planning areas (sub-catchments).
Protection of waters
The Austrian network of running waters comprises 250 gauging points, at which water samples are checked for chemical/physical parameters up to 24 times a year. Sediment examinations (especially checks for heavy-metal contamination) and the determination of the biological water quality are conducted once a year.
Formerly, water(s) protection used to be geared exclusively towards maintaining the purity of water, i.e. keeping out degradable organic substances, foods and pollutants. Today, more emphasis is being place on the structural aspects of waters and thus the aquatic habitat.
For this reason, the notion of “water(s) protection” has been extended to embrace the ecological components that form a central part of the EU Water Framework Directive. In this respect, taking the natural state as a model, ensuring water organisms’ ability to reproduce, and the passability of water bodies are important aspects.
Concept of water-body stewardship (Stream Care Scheme)
In order to cope with the new requirements of an ecologically oriented planning of flood control in combination with the protection of the aquatic habitat, the Federal Water Engineering Administration at the Ministry of Life (“Bundeswasserbauverwaltung”) developed the “Stream Care Scheme” as a major planning tool for protective water management.
In the future, experts in the field of protective water management together with experts on area planning will have to aim at designing the “desired vicinity to the river” in consideration of hazard zone plans so that humans and their settlements will not be endangered by the water.
European Water Framework Directive (EU-WFD)
The European Water Framework Directive provides the framework and the objectives for the protection of water(s) for all EU Member States as well as for the integration of the public.
However, waters are not only important habitats for fish and small animals and sites for plants; they are also areas for living, recreation and adventure for ourselves. Those demands on waters are highly diverse and partly competing. For the purposes of the Water Framework Directive, and considering sustainability, future measures will have to combine and reconcile human demands and ecology.
The WFD promotes the efforts undertaken in Austria to harmonise the necessity of flood control, the utilisation of water power as well as the sustainable development of rural areas with the requirements of waters protection. In this way the securing of near-natural areas of living will be made largely compatible with the agricultural utilisation and settlement of valleys.
Status quo analysis 2005 of the WFD
The WFD stipulates that waters are divided into stretches (= water bodies) and that, in a first step, the impacts of human activity on the water status are assessed. After that, the status has to be monitored by means of a measuring programme in order to eventually deduce measures to improve the status.
So far, the following waters have been analysed in Austria:
- 940 water bodies of running waters with a catchment area of more than 100 km² each (total length of
11,500 km).
- 62 lakes, each with a surface area of over 50 hectares
- 162 near-surface groundwater bodies which, in their entirety, cover Austria, one thermal water body, and
eight groups of profound groundwater bodies
What has been surveyed?
The status of those waters has been assessed according to several criteria. The subject of the study was to which extent waters are influenced by the impact of human utilisations, that is, the introduction of harmful substances, pollutants and nutrients as well as by interventions in the run-off behaviour and structures.
The measuring values relate to biological and chemical-physical ratios and characteristics of the water structure, the so-called “hydromorphological components”:
Biological components: Algae, aquatic plants, small animals living on the bottom of waters and fish.
Physico-chemical components: General ratios like temperature, oxygen, degradable organic substances), nutrients (nitrogen and phosphorous compounds) and hazardous substances.
Hydromorphological components: Shape of the water, its banks and shape of the river bed, run-off behaviour, status of the habitat for fish, micro-organisms and plants.
Central objective “good ecological status”
With the EU Water Framework Directive the maintenance of well-functioning habitats in waters becomes the overall objective. This target situation is also referred to as a “good ecological status”. Wherever biological communities in bodies of water are already at a significant risk, restoring them has been set as the main objective.
According to the EU Directive, this should be achieved by the year 2015. Stock-taking of Austrian bodies of water has been carried out. The resulting report describes the current state of groundwater, rivers, streams and lakes.
Austria needs to take action in some areas in order to achieve a “good ecological status”. In many cases, the structures of rivers and streams has changed primarily because settlement and economic activities have been restricted to the valley bottom and due to the concomitant need for flood protection and use of water power. Improving this situation in the future will become more important than ever. Projects have already been launched to that purpose.
Ecological situation of surface waters today
The water quality of Austria’s water bodies is for the greatest part very good again. Measures taken to remove the organic and chemical pollutants from industrial and municipal sources have for the greatest part been successful. The investments in wastewater purification have thus been worth while. Hazardous substances have been detected only very rarely. As regards organic pollution and nutrient pollution about 80 percent of the water network studied comply with the good status.
Less favourable is the situation of the river structure (= hydromorphological situation). For approximately 56 percent of the assessed network of running waters the assessment indicated that the good status has been missed. Similar figures were determined also in many other European countries. In most cases these problems have a historical cause, namely the utilisation of water power and the protection against floods as well as the establishment of agricultural production areas.
Further, studies were conducted with intensively built-up waters whether the restoration of the good ecological status could have negative impacts on existing utilisations. They include 44 percent of the running-water stretches that were examined. They were provisionally identified as “artificial or heavily modified” waters. For a final identification, to follow by 2009, more surveys are required. To such stretches of waters, lower quality requirements would apply.
Objectives of the Austrian water policy
What are the challenges to be faced? Austria’s water policy aims at implementing the requirements of the Water Framework Directive in an efficient manner. The so-called “river management plans” have to specify how the target situation can be achieved for the individual river basins.
In general, rivers are to maintain their dynamic habitats again, they are to run freely and have the possibility to spread in their environments; fish must not be obstructed by transverse structures so they are able to reach their spawning grounds. It is crucial that underneath diversion hydropower plants residual water flow is sufficient. Also the connection of subsidiary water bodies with the main water bodies is of importance. In intensively farmed areas attention has to be paid to avoiding high nutrient inputs in surface waters and groundwater.
02.07.2008, Lebensministerium Öffentlichkeitsarbeit