6 Natural and Anthropogenic Lakes of River Valleys
103
(b) inflow regulated by means of a pumping station or a flap.
C lake with outflow toward the river
(a) gravitational outflow
(b) regulated outflow.
D lake without surface outflow, isolated from the river
E lake permanently connected with the river
F lake periodically connected with the river.
The complex system is a system of several (at least 2) lake basins, which are
connected by means of a narrow isthmus. As a result of dams constructions, one
reservoir was divided into several smaller ones. Breaks in the dams systems occurred
later, which led to the connection of some of the reservoirs. Lakes with a simple
system may occur within this type.
The formation and functioning of anthropogenic floodplain lakes are determined
by the type and scope of river bed regulation works. The river regulation is generally
defined as hydrotechnical activities (with the use of appropriate structures) aimed
at creating conditions for the formation of a uniform bed of a river with gentle
meandering arches and fixed cross-sections for three characteristic stages: low water
(LW), medium (MW) and high (HW). Measures to achieve this aim are: concentration
of the stream, consolidation of the shore, straightening of excessively sharp curves
of the river, extension of excessive narrowing, i.e., creation of conditions for the free
flow of ice to avoid dangerous blockages, as well as creation and maintenance of a
constant depth necessary for the proper flow [45].
The appearance of a large number of anthropogenic reservoirs in river valleys was
connected with the systematic regulation of major rivers in Poland, which began in
the nineteenth century. Lack of maintenance and renovation of neglected regulatory
buildings caused their technical condition, as well as the whole regulatory system,
was constantly deteriorating. Debris was deposited in the inter-groyne zones, and
new water reservoirs were created. In places where river groynes were destroyed,
blurring was created in existing, already settled inter-groyne spaces. These deformations widened as a result of the swelling wave and further erosion of the reservoir.
Therefore, such waters appeared most often after the passage of large floods, which
meant that these are relatively young objects.
6.5 Studies and Bathymetric Plans of Selected Floodplain
Lakes in Poland
The lakes of river valleys are one of the fastest growing types of water reservoirs and
at the same time the most perishable forms in the landscape. The highest disappearance rate was observed in the case of artificially cutoff anthropogenic lakes [49]. The
studies on floodplain lakes in Poland were carried out to a different extent (hydrological, hydrochemical, bathymetric). They included lakes located in the valleys of
103
(b) inflow regulated by means of a pumping station or a flap.
C lake with outflow toward the river
(a) gravitational outflow
(b) regulated outflow.
D lake without surface outflow, isolated from the river
E lake permanently connected with the river
F lake periodically connected with the river.
The complex system is a system of several (at least 2) lake basins, which are
connected by means of a narrow isthmus. As a result of dams constructions, one
reservoir was divided into several smaller ones. Breaks in the dams systems occurred
later, which led to the connection of some of the reservoirs. Lakes with a simple
system may occur within this type.
The formation and functioning of anthropogenic floodplain lakes are determined
by the type and scope of river bed regulation works. The river regulation is generally
defined as hydrotechnical activities (with the use of appropriate structures) aimed
at creating conditions for the formation of a uniform bed of a river with gentle
meandering arches and fixed cross-sections for three characteristic stages: low water
(LW), medium (MW) and high (HW). Measures to achieve this aim are: concentration
of the stream, consolidation of the shore, straightening of excessively sharp curves
of the river, extension of excessive narrowing, i.e., creation of conditions for the free
flow of ice to avoid dangerous blockages, as well as creation and maintenance of a
constant depth necessary for the proper flow [45].
The appearance of a large number of anthropogenic reservoirs in river valleys was
connected with the systematic regulation of major rivers in Poland, which began in
the nineteenth century. Lack of maintenance and renovation of neglected regulatory
buildings caused their technical condition, as well as the whole regulatory system,
was constantly deteriorating. Debris was deposited in the inter-groyne zones, and
new water reservoirs were created. In places where river groynes were destroyed,
blurring was created in existing, already settled inter-groyne spaces. These deformations widened as a result of the swelling wave and further erosion of the reservoir.
Therefore, such waters appeared most often after the passage of large floods, which
meant that these are relatively young objects.
6.5 Studies and Bathymetric Plans of Selected Floodplain
Lakes in Poland
The lakes of river valleys are one of the fastest growing types of water reservoirs and
at the same time the most perishable forms in the landscape. The highest disappearance rate was observed in the case of artificially cutoff anthropogenic lakes [49]. The
studies on floodplain lakes in Poland were carried out to a different extent (hydrological, hydrochemical, bathymetric). They included lakes located in the valleys of