3 Development and Protection of Water …
45
fishing, which remains a major burden at 2,583 man-days per year. In order to improve
the quality of water in these lakes, it is necessary to modernize wastewater systems,
limit pollution flows from agricultural areas, and manage tourism and recreational
development [20].
Karkonoski National Park features postglacial lakes in the form of ponds and
small peat bog lakes. The latter reflect the pH of their parent bogs and tend to be
acidic at 3.0–3.5 due to the presence of humus acids [22]. PTTK (Polish Tourist
and Sightseeing Society) lodges in the park and private lodges use water from the
park’s lakes. Surface water quality is low due to significant acidity and elevated
concentration of selected ions [23]. Given the low mineral content in the park’s
waters and their strong acidity, they are sensitive to external factors. The main factor is
polluted precipitation water, although the acidity of precipitation has been decreasing
since the 1990s [24].
Bory Tucholskie National Park features 23 natural lakes and one artificial reservoir for a total capacity of 41 mln m
3 . Lake water quality is good and very good. The
park’s lakes feature low mineral content and low nitrogen and phosphorus content—
concentrations 30–40% lower than in other regions in Poland [25, 26]. The only
problem in some of the lakes is low oxygen content in summer and winter [27]. The
lakes’ hydrochemical and biological state varies significantly. Some of the lakes are
humus lakes, while others are transitional lakes at various stages of trophic evolution.
Humus lakes are also outflow-free lakes characterized by cascading patterns relative
to one another and strong water acidity due to the influx of humus substances and
acid rain. Surface waters in the park are affected by groundwater whose chemistry is
driven by the local climate water balance [26]. Lake oligotrophication or dystrophication may be an outcome of changes in hydro-geologic conditions and land cover
[28].
Lake dystrophic processes are also accelerated by human impact in the form
of forest clearing and plowing of arable land before afforestation as well as the
construction of drainage ditches in the park [29]. On the other hand, transitional
lakes are gutter lakes connected with each other via the Struga Siedmiu Jezior. It
is important to note that the trophic state of lakes increases rapidly with the course
of the Struga [26]. The only water usage in the park is that for fish ponds and fish
management catches. Some water is also used by a tree farm in Klosnów. This
is the only surface water collection site in the park—it is found on Lake Ostrowite.
Discharge ranges from 4,000 m
3 to 6,000 m
3 per month. Finally, the park’s hydrologic
system is sensitive to external changes of all types.
Uj´ scie Warty National Park—its current surface water system is the outcome
of a strong human impact in the region [30]. The outcome is a weak hydrographic
network, as manifested by the current surface area of Lake Kostrzy´ nskie (37.2 ha),
which used to cover the area between the Odra and Warta rivers [31]. The existence of
Lake Kostrzy´ nskie and four other lakes formed from ancient river channels depends
on water levels in the Odra and Warta rivers, flood stages, and groundwater levels [30].
Also, there is one lake in the park located on the Northern Polder—Lake Sier˙ zant—
with a surface area of 2.9 ha. The park first and foremost functions as a water retention
area. Water tourism and fishing are also available in the park. Water in the park is
45
fishing, which remains a major burden at 2,583 man-days per year. In order to improve
the quality of water in these lakes, it is necessary to modernize wastewater systems,
limit pollution flows from agricultural areas, and manage tourism and recreational
development [20].
Karkonoski National Park features postglacial lakes in the form of ponds and
small peat bog lakes. The latter reflect the pH of their parent bogs and tend to be
acidic at 3.0–3.5 due to the presence of humus acids [22]. PTTK (Polish Tourist
and Sightseeing Society) lodges in the park and private lodges use water from the
park’s lakes. Surface water quality is low due to significant acidity and elevated
concentration of selected ions [23]. Given the low mineral content in the park’s
waters and their strong acidity, they are sensitive to external factors. The main factor is
polluted precipitation water, although the acidity of precipitation has been decreasing
since the 1990s [24].
Bory Tucholskie National Park features 23 natural lakes and one artificial reservoir for a total capacity of 41 mln m
3 . Lake water quality is good and very good. The
park’s lakes feature low mineral content and low nitrogen and phosphorus content—
concentrations 30–40% lower than in other regions in Poland [25, 26]. The only
problem in some of the lakes is low oxygen content in summer and winter [27]. The
lakes’ hydrochemical and biological state varies significantly. Some of the lakes are
humus lakes, while others are transitional lakes at various stages of trophic evolution.
Humus lakes are also outflow-free lakes characterized by cascading patterns relative
to one another and strong water acidity due to the influx of humus substances and
acid rain. Surface waters in the park are affected by groundwater whose chemistry is
driven by the local climate water balance [26]. Lake oligotrophication or dystrophication may be an outcome of changes in hydro-geologic conditions and land cover
[28].
Lake dystrophic processes are also accelerated by human impact in the form
of forest clearing and plowing of arable land before afforestation as well as the
construction of drainage ditches in the park [29]. On the other hand, transitional
lakes are gutter lakes connected with each other via the Struga Siedmiu Jezior. It
is important to note that the trophic state of lakes increases rapidly with the course
of the Struga [26]. The only water usage in the park is that for fish ponds and fish
management catches. Some water is also used by a tree farm in Klosnów. This
is the only surface water collection site in the park—it is found on Lake Ostrowite.
Discharge ranges from 4,000 m
3 to 6,000 m
3 per month. Finally, the park’s hydrologic
system is sensitive to external changes of all types.
Uj´ scie Warty National Park—its current surface water system is the outcome
of a strong human impact in the region [30]. The outcome is a weak hydrographic
network, as manifested by the current surface area of Lake Kostrzy´ nskie (37.2 ha),
which used to cover the area between the Odra and Warta rivers [31]. The existence of
Lake Kostrzy´ nskie and four other lakes formed from ancient river channels depends
on water levels in the Odra and Warta rivers, flood stages, and groundwater levels [30].
Also, there is one lake in the park located on the Northern Polder—Lake Sier˙ zant—
with a surface area of 2.9 ha. The park first and foremost functions as a water retention
area. Water tourism and fishing are also available in the park. Water in the park is