Problems of ecological monitoring of surface waters

The main objectives of the Water Framework Directive 2000/60/EC of 23 October 2000, establishing a framework for Community action in the field of water policy, is to protect and to prevent all kinds of water from pollution and to achieve by 2015 a good ecological and chemical state of water. One of the tools used to achieve these objectives is monitoring, which should provide consistent and complete information on the state of ecological and chemical status of waters. Control of the dynamics of ecological state changes in aquatic ecosystems is a task of special ecological monitoring, which should be based on principles other than regular monitoring of environmental pollution. The most important component of the monitoring of surface waters is an assessment of their ecological status. For the assessment of ecological status of surface waters various criteria were developed. The main characteristics of the ecological status are usually the indicators of species diversity, reflecting the richness and diversity of water biocenosis. Despite their strength the indicators of biodiversity have some serious drawbacks. It can therefore be assumed that the most adequate criterion that reflects the ecological status of surface water is the material, energetic or kinetic balance of production and destruction of organic matter. At the same time, this balance characterizes the trophic state of water bodies, because the degree of water trophy is conditioned by the final balance of these processes. The indicators presented by the author can be used for the ecological monitoring, for assessing the trophic level of surface waters and at the same time their state of ecological balance. They also can be applied in solving engineering tasks and in mathematical modelling.