96
J. Dawidek et al.
side). This form of basins supply occurs only when there is a difference in the value
of limnological effective rise of crevasses (from the upper and lower side of the water
in the river). Potamophase begins with contrafluent inflow of river waters and “old”
waters pushing deep into the basin. Confluent recharge and the change of direction
of basin supply starts after crossing the shore point, at the height of upper water
crevasse.
Division by the manner of water exchange
The basins of the floodplain lakes are particularly dynamic ecological systems in
which there is a constant exchange of matter and energy. The classic pattern of water
exchange rate in the basin assumes its uninterrupted movement within the entire bowl
(CSR – Continuously Stirred Reactor) [38]. The rate of water exchange in the basin
results primarily from the characteristics of the basin, e.g. geological structure, relief,
surface of the basin, and the bathymetry of the basin itself [39]. In the Polish scientific
literature, there are two types of water exchange in relation to lakes: horizontal and
vertical, and a situation where the role of these forms of exchange is so variable
that none of them is dominant. In the world literature, the rate of water exchange is
generally determined on the basis of the ratio of the capacity of the lake basin to the
volume of the supply (in the case of nondrainage lakes). However, the capacity of
the basin to the drainage (in the case of outflow lakes) or the capacity of the basin
to the sum of the supply and drainage (in the case of flowing lakes) has always been
implemented. The role of genetic forms of supply in terms of groundwater resources
(base flow) or quick flow component of the supply is relatively rarely described in
the literature.
There are three types of floodplain lakes due to the way of water exchange;
evaporation-dominated, exchange-dominated and flood-dominated [40]. In the case
of evaporation-dominated lakes, the vertical form of water exchange in the basin is
dominant. The largest share in the revenue side of the water balance is precipitation,
while the evaporation is the largest share in the expenditure side. Lakes of this type
have short-lived potamophase, and for most of the year, the hydrological condition
of the lake is determined by the resources of the catchment.
In flood-dominated lakes, the quantity and quality of water in the lake basin is
determined by river recharge. The duration of potamophase in a hydrological year
often exceeds six months, which is conducive to equalization of water levels in
the reservoir during the year. Long-lasting potamic recharge also determines the
physicochemical parameters of waters, which are similar to the waters of the parent
river [24]. The most difficult to identify is the type of exchange-dominated lakes,
due to the lack of threshold values of, e.g. evaporation or outflow, or the duration
of potamophase and limnophase. The functioning of such lakes is shaped by both
extrazonal potamic factors and interzonal factors of the catchment.
So far, no precise and objective criterion has been developed for the division of
floodplain lakes due to water exchange. Two criteria can be adopted to objectively
assign floodplain lakes to a specific type:
J. Dawidek et al.
side). This form of basins supply occurs only when there is a difference in the value
of limnological effective rise of crevasses (from the upper and lower side of the water
in the river). Potamophase begins with contrafluent inflow of river waters and “old”
waters pushing deep into the basin. Confluent recharge and the change of direction
of basin supply starts after crossing the shore point, at the height of upper water
crevasse.
Division by the manner of water exchange
The basins of the floodplain lakes are particularly dynamic ecological systems in
which there is a constant exchange of matter and energy. The classic pattern of water
exchange rate in the basin assumes its uninterrupted movement within the entire bowl
(CSR – Continuously Stirred Reactor) [38]. The rate of water exchange in the basin
results primarily from the characteristics of the basin, e.g. geological structure, relief,
surface of the basin, and the bathymetry of the basin itself [39]. In the Polish scientific
literature, there are two types of water exchange in relation to lakes: horizontal and
vertical, and a situation where the role of these forms of exchange is so variable
that none of them is dominant. In the world literature, the rate of water exchange is
generally determined on the basis of the ratio of the capacity of the lake basin to the
volume of the supply (in the case of nondrainage lakes). However, the capacity of
the basin to the drainage (in the case of outflow lakes) or the capacity of the basin
to the sum of the supply and drainage (in the case of flowing lakes) has always been
implemented. The role of genetic forms of supply in terms of groundwater resources
(base flow) or quick flow component of the supply is relatively rarely described in
the literature.
There are three types of floodplain lakes due to the way of water exchange;
evaporation-dominated, exchange-dominated and flood-dominated [40]. In the case
of evaporation-dominated lakes, the vertical form of water exchange in the basin is
dominant. The largest share in the revenue side of the water balance is precipitation,
while the evaporation is the largest share in the expenditure side. Lakes of this type
have short-lived potamophase, and for most of the year, the hydrological condition
of the lake is determined by the resources of the catchment.
In flood-dominated lakes, the quantity and quality of water in the lake basin is
determined by river recharge. The duration of potamophase in a hydrological year
often exceeds six months, which is conducive to equalization of water levels in
the reservoir during the year. Long-lasting potamic recharge also determines the
physicochemical parameters of waters, which are similar to the waters of the parent
river [24]. The most difficult to identify is the type of exchange-dominated lakes,
due to the lack of threshold values of, e.g. evaporation or outflow, or the duration
of potamophase and limnophase. The functioning of such lakes is shaped by both
extrazonal potamic factors and interzonal factors of the catchment.
So far, no precise and objective criterion has been developed for the division of
floodplain lakes due to water exchange. Two criteria can be adopted to objectively
assign floodplain lakes to a specific type: