Monitoring the restoration of waters
Monitoring is needed for provision of information for use in restoration planning. Monitoring during and after restoration also plays an important role in water resources management. For certain sites, the state environmental administration has monitoring data available spanning several decades, which allows reliable examination of eutrophication trends. The monitoring of waters carried out by the state also provides valuable basic information about waters to various research institutes.
However, there are many areas on which there is no information whatsoever regarding water quality and species breakdown. In these areas, observations can be made locally, with measurement of the depth of visibility or of water levels, for instance. Knowledge of changes in aquatic vegetation and fish fauna is also of great help in assessment of the status of the waters and in determination of the need for restoration.
Restoration is best supported by systematic, long-term observation. There are many variables describing the status of waters, which can be divided into the biological and physico‑chemical groups. The former are used as the primary classification criteria. The habitat requirements of fish, algal, aquatic plant and zoobenthic species are fairly well known, so these can be used for deduction of the physico-chemical characteristics of waters. Changes in biological variables require a monitoring period of several years, but the values of physico-chemical variables change more frequently. It is often beneficial if people living on different sides of a water body can participate in the observation.
Observations about the status of waters are important
- for assessing the current status and the changes in it,
- for deciding whether measures are needed,
- for estimating the scope of such measures, and
- for assessing the effects of the measures implemented.
What is monitored?
There are many variables describing the status of waters. These can be divided into three groups: the biological, physico-chemical and morphological. Biological variables are used as the primary classification criteria. The habitat requirements of fish, algae, aquatic plants and zoobenthic species are fairly well known, so they can be used for deduction of physico-chemical and morphological characteristics of waters. Changes in biological variables require a monitoring period of several years, but the values of physico-chemical variables change more frequently. Certain morphological characteristics of waters, such as the structure of the shores and bottom, are preconditions for biological diversity, and they also have a great impact on physico-chemical variables.