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D. Absalon et al.
the group of specific synthetic and non-synthetic pollutants and also chemical indexes
characterising the presence of substances particularly harmful to water environment,
which have been identified in the catchment.
The aim of monitoring carried out by the State Inspection for Environmental
Protection is providing knowledge about the status of water, necessary for taking
actions for the improvement of the condition and protection of water from pollution.
Research results obtained based on the monitoring enable classification of elements
of water quality, ecological status or chemical status as well as the assessment of the
status of surface water bodies that are dam reservoirs.
The analysis encompassed only these reservoirs for which operational or diagnostic monitoring was carried out in the years 2012–2017, and the scope of tasks
was comparable for them.
7.3 Conditions of Water Quality in Dam
Reservoirs—Selected Issues
The studied reservoirs are located in different regions of Poland, and they perform
different functions, e.g., flood protection, power engineering, water supply, tourism,
and recreation, aiding water transport, and fish harvesting. Some of them are multipurpose reservoirs serving many functions at the same time. An exception is the
Czaniec reservoir (the last one in the Soła Cascade) which only supplies potable
water. The analysed dam reservoirs have a very diversified time of water exchange
and ability to accumulate river load. Water exchange conditions and their morphometric parameters influence water quality. Pollutant load in the reservoirs depends
mainly on the degree of human impact in their catchment [27]. Substances polluting
water come mainly from point sources and dispersed sources [28]. Nowadays, rivers
in Poland are still heavily polluted with pollutants from sewage and agriculture
[29]. In the case of sewage discharged to water, these may by toxic substances such
as heavy metals, polycyclic aromatic hydrocarbons (PAHs) or petroleum products.
Surface runoff from agricultural areas contaminates water with fertilising substances
(organic and mineral) and plant protection sprays (pesticides). Point sources and
dispersed sources are sources of biogenic substances (phosphorus and nitrogen).
The process of eutrophication caused by human activity is called cultural eutrophication [30]. Pollutants reaching water easily connect to the silt and clay sediment
fraction and are thus transported in the deep water as suspended load. The chance
of these pollutants being trapped in sediments in reservoirs may contribute to the
improvement of water quality downstream of the reservoir [31]. Dam reservoirs trap
clastic and organic material, transported in the solid form and diluted. Processes
of accumulation of material in reservoirs depend on many factors constant or variable in time, e.g.: size and shape of the reservoir, number and quality of river load
brought from the catchment, and mainly the level of water in the reservoir and the
course of hydrological phenomena in the river on which the reservoir was formed.
D. Absalon et al.
the group of specific synthetic and non-synthetic pollutants and also chemical indexes
characterising the presence of substances particularly harmful to water environment,
which have been identified in the catchment.
The aim of monitoring carried out by the State Inspection for Environmental
Protection is providing knowledge about the status of water, necessary for taking
actions for the improvement of the condition and protection of water from pollution.
Research results obtained based on the monitoring enable classification of elements
of water quality, ecological status or chemical status as well as the assessment of the
status of surface water bodies that are dam reservoirs.
The analysis encompassed only these reservoirs for which operational or diagnostic monitoring was carried out in the years 2012–2017, and the scope of tasks
was comparable for them.
7.3 Conditions of Water Quality in Dam
Reservoirs—Selected Issues
The studied reservoirs are located in different regions of Poland, and they perform
different functions, e.g., flood protection, power engineering, water supply, tourism,
and recreation, aiding water transport, and fish harvesting. Some of them are multipurpose reservoirs serving many functions at the same time. An exception is the
Czaniec reservoir (the last one in the Soła Cascade) which only supplies potable
water. The analysed dam reservoirs have a very diversified time of water exchange
and ability to accumulate river load. Water exchange conditions and their morphometric parameters influence water quality. Pollutant load in the reservoirs depends
mainly on the degree of human impact in their catchment [27]. Substances polluting
water come mainly from point sources and dispersed sources [28]. Nowadays, rivers
in Poland are still heavily polluted with pollutants from sewage and agriculture
[29]. In the case of sewage discharged to water, these may by toxic substances such
as heavy metals, polycyclic aromatic hydrocarbons (PAHs) or petroleum products.
Surface runoff from agricultural areas contaminates water with fertilising substances
(organic and mineral) and plant protection sprays (pesticides). Point sources and
dispersed sources are sources of biogenic substances (phosphorus and nitrogen).
The process of eutrophication caused by human activity is called cultural eutrophication [30]. Pollutants reaching water easily connect to the silt and clay sediment
fraction and are thus transported in the deep water as suspended load. The chance
of these pollutants being trapped in sediments in reservoirs may contribute to the
improvement of water quality downstream of the reservoir [31]. Dam reservoirs trap
clastic and organic material, transported in the solid form and diluted. Processes
of accumulation of material in reservoirs depend on many factors constant or variable in time, e.g.: size and shape of the reservoir, number and quality of river load
brought from the catchment, and mainly the level of water in the reservoir and the
course of hydrological phenomena in the river on which the reservoir was formed.