78
M. Rz˛ etała
Tertiary sediments present in the bottom of the basin and also from the waste used to
backfill the flooded mineral working in the initial period of land reclamation. Such
an increase in salinity between reservoir inflow (c—513.0−602.4 μS/cm, Na
+ —
8.3−19.1 mg/dm
3 , Cl
− —17.0−43.0 mg/dm
3 ) and outflow (c—522.0−658.0 μS/cm,
Na
+ —21.5−39.2 mg/dm
3 , Cl
− —63.2−121.0 mg/dm
3 ) has not been documented in
limnological studies to date and points to the effects of man-made transformations
of the environment which create new directions for water migration via old mines
which are now filled with water [18]. The process of transfer of saline water outside
Upper Silesia via surface watercourses should be considered a highly undesirable
phenomenon.
4.6 Role of Water Bodies
Artificial water bodies in Poland mostly serve numerous functions despite the many
environmental protection problems related to the lentic water environment [7, 10, 18,
24, 25, 43]. Together with their immediate surroundings, they fulfil important natural
and landscape roles, e.g. serving as locations where birds breed and nest, shaping
the local climate and microclimate, influencing the water self-purification process
and favouring the formation of mineral deposits [10, 44, 45]. Storage reservoirs are
used primarily for economic purposes such as water supply (industrial, municipal,
agricultural), flood protection, recreation and tourism, the breeding of fish and other
aquatic organisms, energy production, inland transport, the extraction of mineral
resources, etc. [46].
4.6.1 Flood Control Importance
Flood protection is among the most important functions of anthropogenic reservoirs.
In practice, many water bodies are of little or no flood protection relevance owing to
their limited or absent water damming potential (such water bodies are very similar
to natural lakes). Most water bodies can be made to serve flood protection purposes,
but usually, only the largest reservoirs enable the effective reduction of flood waves.
It is especially those reservoirs which offer flood control storage, and a large part of
their usable storage often remains available during high water stages. The amount of
flood control storage is determined to take into account environmental conditions in
the water body catchment area. Therefore, it varies and ranges from a few hm
3 (e.g.
the Dzier˙ zno Du˙ ze, Przeczyce, Por˛ abka, Poraj, Sulejów, D˛ ebe, Topola, Kozielno,
Bukówka Reservoirs) through around a dozen hm
3 (e.g. the Wióry or Turawa Reservoirs) to several dozen hm
3 (e.g. the Goczałkowice, Tresna, Dobczyce, Czorsztyn,
Ro˙ znów, Solina, Włocławek, Nysa, Otmuchów Reservoirs).
So-called dry reservoirs and flood polders, in which water is retained only during
high-water stages, are also used to control flooding. The largest polders are Buków,
M. Rz˛ etała
Tertiary sediments present in the bottom of the basin and also from the waste used to
backfill the flooded mineral working in the initial period of land reclamation. Such
an increase in salinity between reservoir inflow (c—513.0−602.4 μS/cm, Na
+ —
8.3−19.1 mg/dm
3 , Cl
− —17.0−43.0 mg/dm
3 ) and outflow (c—522.0−658.0 μS/cm,
Na
+ —21.5−39.2 mg/dm
3 , Cl
− —63.2−121.0 mg/dm
3 ) has not been documented in
limnological studies to date and points to the effects of man-made transformations
of the environment which create new directions for water migration via old mines
which are now filled with water [18]. The process of transfer of saline water outside
Upper Silesia via surface watercourses should be considered a highly undesirable
phenomenon.
4.6 Role of Water Bodies
Artificial water bodies in Poland mostly serve numerous functions despite the many
environmental protection problems related to the lentic water environment [7, 10, 18,
24, 25, 43]. Together with their immediate surroundings, they fulfil important natural
and landscape roles, e.g. serving as locations where birds breed and nest, shaping
the local climate and microclimate, influencing the water self-purification process
and favouring the formation of mineral deposits [10, 44, 45]. Storage reservoirs are
used primarily for economic purposes such as water supply (industrial, municipal,
agricultural), flood protection, recreation and tourism, the breeding of fish and other
aquatic organisms, energy production, inland transport, the extraction of mineral
resources, etc. [46].
4.6.1 Flood Control Importance
Flood protection is among the most important functions of anthropogenic reservoirs.
In practice, many water bodies are of little or no flood protection relevance owing to
their limited or absent water damming potential (such water bodies are very similar
to natural lakes). Most water bodies can be made to serve flood protection purposes,
but usually, only the largest reservoirs enable the effective reduction of flood waves.
It is especially those reservoirs which offer flood control storage, and a large part of
their usable storage often remains available during high water stages. The amount of
flood control storage is determined to take into account environmental conditions in
the water body catchment area. Therefore, it varies and ranges from a few hm
3 (e.g.
the Dzier˙ zno Du˙ ze, Przeczyce, Por˛ abka, Poraj, Sulejów, D˛ ebe, Topola, Kozielno,
Bukówka Reservoirs) through around a dozen hm
3 (e.g. the Wióry or Turawa Reservoirs) to several dozen hm
3 (e.g. the Goczałkowice, Tresna, Dobczyce, Czorsztyn,
Ro˙ znów, Solina, Włocławek, Nysa, Otmuchów Reservoirs).
So-called dry reservoirs and flood polders, in which water is retained only during
high-water stages, are also used to control flooding. The largest polders are Buków,