68
M. Rz˛ etała
4.3 Number of Water Bodies and Morphometric
Parameters
The number of artificial water bodies is difficult to determine, mainly due to the fact
that we do not know how many small water storage facilities there are. Inventories of
water bodies carried out within some catchments or within individual administrative
units point to rapid changes in the number and capacity of such reservoirs. The
number, water area and retention capacity of the largest anthropogenic water bodies
have also been increasing steadily. In 1998, there were 40 water bodies in Poland
with capacities greater than 10 hm
3 each, which had a total capacity of 3.2 km
3 and
an area of 463 km
2 , and there were another 61 water bodies with capacities ranging
from 1 to 10 hm
3 each [14]. Two decades later, there are already 50 water bodies with
a capacity greater than 10 hm
3 each. Their total retention capacity is slightly more
than 3.7 km
3 , and their total area is 530 km
2 (Table 4.1). Choi´ nski and Skowron [14]
state that the total capacity of water bodies (with capacities greater than 1 hm
3 ) in
Poland accounts for around 18% of the water resources retained by Polish lakes and
around 6% of the volume of water flowing out of the territory of Poland annually,
and the total area of these water bodies accounts for nearly 18% of the total area of
lakes in Poland. The total area of all artificial water bodies in Poland is estimated
at around 1,000 km
2 , and the corresponding water resources amount to several km
3
[14].
Some areas in Poland deserve to be called anthropogenic lake districts owing to
the number of water bodies present there and their total area [15, 16]. This label
is used to denote the Muskau Bend—an area situated close to the border in southwestern Poland where there are many such water bodies in the former lignite mining
area [17]. A similar name is also given to the Silesian Upland and the O´ swi˛ ecim
Basin together with the outskirts of the neighbouring regions in southern Poland
[18]. The Upper Silesian Anthropogenic Lake District is the largest such district in
Poland (Fig. 4.6). It covers an area of 6,800 km
2 and includes approximately 4,700
water bodies. There are 70.5 bodies of water per 100 km
2 in the area, its lake density
amounts to 2.74%, and the total water surface area is 185.4 km
2 [18]. In the 1960s,
only 3,100 water bodies with a total area of 113.4 km
2 were present within the Upper
Silesian Anthropogenic Lake District. Lake density amounted to 1.68%, and there
were on average 45.77 bodies of water per 100 km
2 [19]. Peculiar features of the
Upper Silesian Anthropogenic Lake District include the diverse origins of the water
bodies found there and the high urbanisation level of the area (the Lake District
coincides, among others, with the Upper Silesia-D˛ abrowa Basin Metropolis).
4.4 Selected Issues of Water Balance
The water balance of anthropogenic water bodies is highly complex, which results
from the complexity of both natural (e.g. climate) and anthropogenic (e.g. water
transfers, dynamic changes in water body surface) conditions that determine this
M. Rz˛ etała
4.3 Number of Water Bodies and Morphometric
Parameters
The number of artificial water bodies is difficult to determine, mainly due to the fact
that we do not know how many small water storage facilities there are. Inventories of
water bodies carried out within some catchments or within individual administrative
units point to rapid changes in the number and capacity of such reservoirs. The
number, water area and retention capacity of the largest anthropogenic water bodies
have also been increasing steadily. In 1998, there were 40 water bodies in Poland
with capacities greater than 10 hm
3 each, which had a total capacity of 3.2 km
3 and
an area of 463 km
2 , and there were another 61 water bodies with capacities ranging
from 1 to 10 hm
3 each [14]. Two decades later, there are already 50 water bodies with
a capacity greater than 10 hm
3 each. Their total retention capacity is slightly more
than 3.7 km
3 , and their total area is 530 km
2 (Table 4.1). Choi´ nski and Skowron [14]
state that the total capacity of water bodies (with capacities greater than 1 hm
3 ) in
Poland accounts for around 18% of the water resources retained by Polish lakes and
around 6% of the volume of water flowing out of the territory of Poland annually,
and the total area of these water bodies accounts for nearly 18% of the total area of
lakes in Poland. The total area of all artificial water bodies in Poland is estimated
at around 1,000 km
2 , and the corresponding water resources amount to several km
3
[14].
Some areas in Poland deserve to be called anthropogenic lake districts owing to
the number of water bodies present there and their total area [15, 16]. This label
is used to denote the Muskau Bend—an area situated close to the border in southwestern Poland where there are many such water bodies in the former lignite mining
area [17]. A similar name is also given to the Silesian Upland and the O´ swi˛ ecim
Basin together with the outskirts of the neighbouring regions in southern Poland
[18]. The Upper Silesian Anthropogenic Lake District is the largest such district in
Poland (Fig. 4.6). It covers an area of 6,800 km
2 and includes approximately 4,700
water bodies. There are 70.5 bodies of water per 100 km
2 in the area, its lake density
amounts to 2.74%, and the total water surface area is 185.4 km
2 [18]. In the 1960s,
only 3,100 water bodies with a total area of 113.4 km
2 were present within the Upper
Silesian Anthropogenic Lake District. Lake density amounted to 1.68%, and there
were on average 45.77 bodies of water per 100 km
2 [19]. Peculiar features of the
Upper Silesian Anthropogenic Lake District include the diverse origins of the water
bodies found there and the high urbanisation level of the area (the Lake District
coincides, among others, with the Upper Silesia-D˛ abrowa Basin Metropolis).
4.4 Selected Issues of Water Balance
The water balance of anthropogenic water bodies is highly complex, which results
from the complexity of both natural (e.g. climate) and anthropogenic (e.g. water
transfers, dynamic changes in water body surface) conditions that determine this