16 The State of Water and Sewage …
379
people/1 km
2 ). Voivodships with the lowest population density are: Podlaskie (59
people/1 km
2 ) and Warmi´ nsko-Mazurskie (60 people/1 km
2 ). Less than 100 people
per 1 km
2 also live in the following voivodships: Lubuskie, Zachodniopomorskie and
Lubelskie. The largest population is recorded in cities. In nine most densely populated ones there are over 3000 people per 1 km
2 . In Poland, on average, there are 52
people per 1 km
2 in rural areas [22]. The cities with the largest population include:
Warsaw (1,744,351 people), Kraków (761,069), Łód´ z (700,982), Wrocław (635,759),
Pozna´ n, Gda´ nsk, Szczecin, Bydgoszcz, Lublin and Katowice—as of December 31,
2015.
Water resources accumulated in rivers, lakes and underground waters depend
on rainfall, influencing their supply and their natural renewal. The average annual
amount of precipitation in Poland in the years 1951–2015 was 625 mm. The total
renewable resources of Poland’s surface waters were described as the average annual
surface water runoff. Depending on the assumed period, the value of the average
annual outflow from the territory of Poland varies and fits in the range of 60–64 km
3
[26, 27]. The average annual total outflow from the territory of Poland in the years
1951–2015 was about 61 km
3 , while it ranged from 37.5 km
3 in 1954 to 89.9 km
3
in 1981 [28]). There is an explicit irregularity in the total outflow, which manifests
itself in the form of alternating cycles of years with high and low outflows. Clear
periods of high outflows occurred in 1977–1982, 1997–2002 and 2010–2011, while
low outflows occurred in 1988–1993 and 2003–2009. An increased frequency of high
and low outflows alternately has been recorded since 2001 [20]. In 2010, the outflow
was exceptionally high and amounted to 86.9 km
3 , while in 2015 it was extremely
low—40.8 km
3 [28].
In the analyzed period of 1999–2015, the average outflow for Poland was 61.1 km
3 .
The highest values were recorded in 2010 and they amounted to 86.9 km
3 , when a
rainfall flood occurred in Poland [25, 29]. The lowest outflow values were recorded
in 2015 and it amounted to 40.8 km
3 , which was the result of hydrological drought
occurring almost all over Poland [19]. In comparison to the other European countries,
the outflow from Poland is small (Michalczyk and Sposób in this volume, KubiakWójcicka in this volume). The countries with lower water resources include Belgium,
the Czech Republic, Denmark, Ireland, Luxembourg and Switzerland [23]. However,
due to the population of particular countries, the size of water resources is not so
favorable in Poland. On average, in the years 1999-2015, there were 1601 m
3 of
water per capita. In Europe, this rate is three times higher, and in the world even four
times higher than in Poland [18, 25, 26].
16.4 The State of Water and Sewage Management
in Poland in the Years 1999–2015
Depending on the analyzed period, the volume of water intake in Poland was
changing. The largest total amount of water intake in Poland was 14.03 km
3 (1990),
while the smallest was 10.5 km
3 (2015) [17]. Total water consumption in Poland
379
people/1 km
2 ). Voivodships with the lowest population density are: Podlaskie (59
people/1 km
2 ) and Warmi´ nsko-Mazurskie (60 people/1 km
2 ). Less than 100 people
per 1 km
2 also live in the following voivodships: Lubuskie, Zachodniopomorskie and
Lubelskie. The largest population is recorded in cities. In nine most densely populated ones there are over 3000 people per 1 km
2 . In Poland, on average, there are 52
people per 1 km
2 in rural areas [22]. The cities with the largest population include:
Warsaw (1,744,351 people), Kraków (761,069), Łód´ z (700,982), Wrocław (635,759),
Pozna´ n, Gda´ nsk, Szczecin, Bydgoszcz, Lublin and Katowice—as of December 31,
2015.
Water resources accumulated in rivers, lakes and underground waters depend
on rainfall, influencing their supply and their natural renewal. The average annual
amount of precipitation in Poland in the years 1951–2015 was 625 mm. The total
renewable resources of Poland’s surface waters were described as the average annual
surface water runoff. Depending on the assumed period, the value of the average
annual outflow from the territory of Poland varies and fits in the range of 60–64 km
3
[26, 27]. The average annual total outflow from the territory of Poland in the years
1951–2015 was about 61 km
3 , while it ranged from 37.5 km
3 in 1954 to 89.9 km
3
in 1981 [28]). There is an explicit irregularity in the total outflow, which manifests
itself in the form of alternating cycles of years with high and low outflows. Clear
periods of high outflows occurred in 1977–1982, 1997–2002 and 2010–2011, while
low outflows occurred in 1988–1993 and 2003–2009. An increased frequency of high
and low outflows alternately has been recorded since 2001 [20]. In 2010, the outflow
was exceptionally high and amounted to 86.9 km
3 , while in 2015 it was extremely
low—40.8 km
3 [28].
In the analyzed period of 1999–2015, the average outflow for Poland was 61.1 km
3 .
The highest values were recorded in 2010 and they amounted to 86.9 km
3 , when a
rainfall flood occurred in Poland [25, 29]. The lowest outflow values were recorded
in 2015 and it amounted to 40.8 km
3 , which was the result of hydrological drought
occurring almost all over Poland [19]. In comparison to the other European countries,
the outflow from Poland is small (Michalczyk and Sposób in this volume, KubiakWójcicka in this volume). The countries with lower water resources include Belgium,
the Czech Republic, Denmark, Ireland, Luxembourg and Switzerland [23]. However,
due to the population of particular countries, the size of water resources is not so
favorable in Poland. On average, in the years 1999-2015, there were 1601 m
3 of
water per capita. In Europe, this rate is three times higher, and in the world even four
times higher than in Poland [18, 25, 26].
16.4 The State of Water and Sewage Management
in Poland in the Years 1999–2015
Depending on the analyzed period, the volume of water intake in Poland was
changing. The largest total amount of water intake in Poland was 14.03 km
3 (1990),
while the smallest was 10.5 km
3 (2015) [17]. Total water consumption in Poland