92
J. Dawidek et al.
– dish lakes with the index size below five. They were characterized by slow
water movement in the basin and longer water exchange time (mainly based
on atmospheric supply).
Division by location in the valley
The location of the lake in the valley, in relation to the river bed or the edge of the
lagoon terrace, may also be a criterion for lakes classification. Four different types
of floodplain lakes can be separated:
– the lakes of modern meander belt. These are mainly oxbows and inter-levee lakes,
generally referred to as near-bed lakes.
– under-edge lakes. They are located on the opposite side of the floodplain terrace in
relation to the above mentioned lakes. They are located in sub-edge depressions.
They generally have a small surface area and the depth of the basin.
– lakes of the higher floodplain terrace
– large-radius oxbow lakes. They rarely occur, far from the river bed and are the
oldest lakes. They are characterized by very advanced processes of atrophy due
to silting and overgrowing of the basin.
Division by manner of lake connection with the river
The criterion of the lake belonging to a specific group is the way of its basin
connecting with the river. Three groups of lakes can be distinguished:
– lotic lakes, open lakes, well oxygenated reservoirs, rich in nutrients with a relatively fast metabolism. They are characterized by an apparent slowdown in the
rate of succession [30].
– lentic lakes, closed [31] with a very short duration of potamophase, which favors
the formation and maintenance of oxygen deficits. Denitrification and sulfate
reduction processes often dominate in bottom zones. The circulation of matter in
such lakes takes place mainly on the basis of indigenous substances.
– semiopen, semi-lotic lakes, characterized by a wide range of hydrological changes,
which results in differentiation of aerobic conditions and water trophy [32], as
well as a large mosaic of habitats.
In each of the above mentioned groups, there are also three forms that take into
account the shape of the lake. Straight, complex and irregular lakes differ in the
degree of complexity of the shoreline of the basins. In the case of straight reservoirs,
there is usually one formed basin, typically curved (croissant), being a part of a cutoff
river meander. The basins of complex lakes are usually connected through channels.
Sometimes it is one basin with a developed system of arms. Irregular lakes have
the most complex shape. These are usually several basins connected or a system of
irrigated inter-splitter depressions.
The method of connecting the lake with the river determines the dynamics of the
ecosystem and the physicochemical composition of the water. This issue is widely
discussed in the literature [16, 23, 33–36].
J. Dawidek et al.
– dish lakes with the index size below five. They were characterized by slow
water movement in the basin and longer water exchange time (mainly based
on atmospheric supply).
Division by location in the valley
The location of the lake in the valley, in relation to the river bed or the edge of the
lagoon terrace, may also be a criterion for lakes classification. Four different types
of floodplain lakes can be separated:
– the lakes of modern meander belt. These are mainly oxbows and inter-levee lakes,
generally referred to as near-bed lakes.
– under-edge lakes. They are located on the opposite side of the floodplain terrace in
relation to the above mentioned lakes. They are located in sub-edge depressions.
They generally have a small surface area and the depth of the basin.
– lakes of the higher floodplain terrace
– large-radius oxbow lakes. They rarely occur, far from the river bed and are the
oldest lakes. They are characterized by very advanced processes of atrophy due
to silting and overgrowing of the basin.
Division by manner of lake connection with the river
The criterion of the lake belonging to a specific group is the way of its basin
connecting with the river. Three groups of lakes can be distinguished:
– lotic lakes, open lakes, well oxygenated reservoirs, rich in nutrients with a relatively fast metabolism. They are characterized by an apparent slowdown in the
rate of succession [30].
– lentic lakes, closed [31] with a very short duration of potamophase, which favors
the formation and maintenance of oxygen deficits. Denitrification and sulfate
reduction processes often dominate in bottom zones. The circulation of matter in
such lakes takes place mainly on the basis of indigenous substances.
– semiopen, semi-lotic lakes, characterized by a wide range of hydrological changes,
which results in differentiation of aerobic conditions and water trophy [32], as
well as a large mosaic of habitats.
In each of the above mentioned groups, there are also three forms that take into
account the shape of the lake. Straight, complex and irregular lakes differ in the
degree of complexity of the shoreline of the basins. In the case of straight reservoirs,
there is usually one formed basin, typically curved (croissant), being a part of a cutoff
river meander. The basins of complex lakes are usually connected through channels.
Sometimes it is one basin with a developed system of arms. Irregular lakes have
the most complex shape. These are usually several basins connected or a system of
irrigated inter-splitter depressions.
The method of connecting the lake with the river determines the dynamics of the
ecosystem and the physicochemical composition of the water. This issue is widely
discussed in the literature [16, 23, 33–36].