2 Assessment of Water Resources in Poland
17
2.2 The Water Resources of Poland
The size of global water resources depends primarily on climatic conditions.
According to the International Glossary of Hydrology Dictionary [3], water resources
are defined as the totality of currently and potentially available waters of the quantities
and qualities required to meet specific needs. However, water resources are usually
only taken to be those waters involved in the circulation of precipitation falling on
land and its transformation into outflow (the land phase of the hydrological cycle).
Many studies, therefore, equate water resources with the river outflow of a given
area.
Water resources are very variable, both temporally and spatially, which results
from the temporally and spatially variable distribution of atmospheric precipitation,
whose course is random (Fig. 2.1). Changes in the distribution of atmospheric precipitation may cause extreme phenomena, including floods and droughts. The occurrence of sudden and frequent precipitation can lead to frequent floods. In turn, a
lack of precipitation may lead to drought and, consequently, to desertification. Water
resources are, therefore, extremely sensitive to climate change. Climate change in
Poland is contributing to the increased frequency of droughts and floods resulting
from deficits or high levels of precipitation [4].
The amount of water resources is best determined by total outflow. It is calculated
based on long-term observation of flow in entire basins—including outside Poland—
from a total area of 351,028 km
2 , which is 12.3% larger than the country itself.
The average annual total outflow from Poland in the years 1951–2015 was about
61 km
3 , ranging from 37.5 km
3 in 1954 to 89.9 km
3 in 1981 [5]. For the shorter
period 1975–2015, the average annual total outflow was 63.2 km
3 . Figure 2.1 shows
0
10
20
30
40
50
60
70
80
90
0
100
200
300
400
500
600
700
800
900
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
2009
2011
2013
2015
km 3
mm
Precipitaon
Water oulow total
Fig. 2.1 Precipitation and outflow, 1971–2015 (own study based on the data from [1])
17
2.2 The Water Resources of Poland
The size of global water resources depends primarily on climatic conditions.
According to the International Glossary of Hydrology Dictionary [3], water resources
are defined as the totality of currently and potentially available waters of the quantities
and qualities required to meet specific needs. However, water resources are usually
only taken to be those waters involved in the circulation of precipitation falling on
land and its transformation into outflow (the land phase of the hydrological cycle).
Many studies, therefore, equate water resources with the river outflow of a given
area.
Water resources are very variable, both temporally and spatially, which results
from the temporally and spatially variable distribution of atmospheric precipitation,
whose course is random (Fig. 2.1). Changes in the distribution of atmospheric precipitation may cause extreme phenomena, including floods and droughts. The occurrence of sudden and frequent precipitation can lead to frequent floods. In turn, a
lack of precipitation may lead to drought and, consequently, to desertification. Water
resources are, therefore, extremely sensitive to climate change. Climate change in
Poland is contributing to the increased frequency of droughts and floods resulting
from deficits or high levels of precipitation [4].
The amount of water resources is best determined by total outflow. It is calculated
based on long-term observation of flow in entire basins—including outside Poland—
from a total area of 351,028 km
2 , which is 12.3% larger than the country itself.
The average annual total outflow from Poland in the years 1951–2015 was about
61 km
3 , ranging from 37.5 km
3 in 1954 to 89.9 km
3 in 1981 [5]. For the shorter
period 1975–2015, the average annual total outflow was 63.2 km
3 . Figure 2.1 shows
0
10
20
30
40
50
60
70
80
90
0
100
200
300
400
500
600
700
800
900
1975
1977
1979
1981
1983
1985
1987
1989
1991
1993
1995
1997
1999
2001
2003
2005
2007
2009
2011
2013
2015
km 3
mm
Precipitaon
Water oulow total
Fig. 2.1 Precipitation and outflow, 1971–2015 (own study based on the data from [1])