404
T. Ciupa and R. Suligowski
official reports of state and local government institutions, as well as numerous reports
in the mass media, are an important source of information reaching a wide range of
society. According to media reports, in Polish cities only in the summer half of
2018 there were several dozen flash floods, for example: 5/10—Bolesławiec, 5/11—
Gda´ nsk, Łód´ z, 5/16—Brzeziny, 6/2—Szczecin, 7/11—Pozna´ n, Lubo´ n, 7/15—
Bydgoszcz, 7/16—Białystok, 7/17—Radomsko, 7/18—Łód´ z, Siedlce, 7/20—Szczawnica; 7/27—Pleszew, 7/30—Pabianice, Bytom Jaworzno, Ruda ´
Sl˛ aska, Tarnowskie
Góry, 8/1—Pleszew, 8/14—Limanowa, 9/1—Ruda Sl˛ aska, Opole, 9/4—Białystok,
Słupsk, 9/9—Ostrowiec ´
Swi˛ etokrzyski, 9/17—Zakopane, Nowy Targ, Kro´ scienko.
Some of them concerned descriptions of the effects of events related to flooding of
roads, parking lots, metro stations, residential and commercial buildings. In general,
they were the result of insufficient capacity and patency of rainwater drainage,
capacity of hydraulic engineering structures and valleys, etc.
Much greater scale of threats in some Polish cities is caused by transit rivers,
especially during regional floods with rainy genesis, characteristic for the summer
season [95]. They have a large spatial coverage of the inundation, a long duration
of the flood, and severe economic losses are the consequence. A typical mechanism
of their formation is the inflow of warm and humid sea air from the northern part
of the Mediterranean (mainly the Adriatic Sea) or the Black Sea, controlled by
a low-pressure center with a center over mid- or southern Poland. There is longlasting high-intensity precipitation covering a large area of Poland then. Typical
examples of this large-scale mechanism in the last few decades were the floods in
July 1970 [96] and 1997—millennial flood [97, 98], August 1972 [99], May and
June 2010 [100, 101]. The most severe effects were related to the two largest rivers:
the Vistula—1020 km long and the Odra—840 km and their upper tributaries [102,
103]. The most frequently mentioned cities located by the Vistula River that have
been affected by catastrophic floods in history are: Kraków, Sandomierz, Warszawa,
Tczew, Gda´ nsk, and Malbork [104, 105], and by Odra: Racibórz, K˛ edzierzyn-Ko´ zle,
Opole, Wrocław, Słubice, Nowa Sól, Krosno Odrza´ nskie [106, 107]. Flooded rivers
inundated urban areas located behind the river shafts numerously, and the resulting
floodplains persisted for many days. The flood in July 1997 caused 55 people to
die in Poland. About 100,000 people were evacuated at that time, and 47,000 of
residential buildings, 1,700 bridges and culverts, 71 hospitals, almost 1,000 schools
and kindergartens, 100 intakes of drinking water were flooded and damaged [108].
Cities in Poland are less and less threatened by mid-winter and spring thaw floods.
A large event of this type was in March-April 1979, due to the very intense longlasting snowfall at the turn of 1978/1979. The cities located in the Bug and Narew
basins (including Ostroł˛ eka, Pułtusk) and Warta basin (including Pozna´ n, Kalisz)
were at risk. Recently, the thaw flood occurred at the turn of February and March
2011 in the Note´ c and lower Warta catchments (Pozna´ n).
Small rivers draining cities during the mid-winter and spring thaw are not a flood
hazard, because due to the accelerated melting of the snow cover and increased
evaporation within roads, parking lots, built-up areas, etc. there is a significant loss
of water resources accumulated in the snow cover. For example, in the urbanized
catchments of Kielce, the average maximum specific runoff in March (1998–2003)
T. Ciupa and R. Suligowski
official reports of state and local government institutions, as well as numerous reports
in the mass media, are an important source of information reaching a wide range of
society. According to media reports, in Polish cities only in the summer half of
2018 there were several dozen flash floods, for example: 5/10—Bolesławiec, 5/11—
Gda´ nsk, Łód´ z, 5/16—Brzeziny, 6/2—Szczecin, 7/11—Pozna´ n, Lubo´ n, 7/15—
Bydgoszcz, 7/16—Białystok, 7/17—Radomsko, 7/18—Łód´ z, Siedlce, 7/20—Szczawnica; 7/27—Pleszew, 7/30—Pabianice, Bytom Jaworzno, Ruda ´
Sl˛ aska, Tarnowskie
Góry, 8/1—Pleszew, 8/14—Limanowa, 9/1—Ruda Sl˛ aska, Opole, 9/4—Białystok,
Słupsk, 9/9—Ostrowiec ´
Swi˛ etokrzyski, 9/17—Zakopane, Nowy Targ, Kro´ scienko.
Some of them concerned descriptions of the effects of events related to flooding of
roads, parking lots, metro stations, residential and commercial buildings. In general,
they were the result of insufficient capacity and patency of rainwater drainage,
capacity of hydraulic engineering structures and valleys, etc.
Much greater scale of threats in some Polish cities is caused by transit rivers,
especially during regional floods with rainy genesis, characteristic for the summer
season [95]. They have a large spatial coverage of the inundation, a long duration
of the flood, and severe economic losses are the consequence. A typical mechanism
of their formation is the inflow of warm and humid sea air from the northern part
of the Mediterranean (mainly the Adriatic Sea) or the Black Sea, controlled by
a low-pressure center with a center over mid- or southern Poland. There is longlasting high-intensity precipitation covering a large area of Poland then. Typical
examples of this large-scale mechanism in the last few decades were the floods in
July 1970 [96] and 1997—millennial flood [97, 98], August 1972 [99], May and
June 2010 [100, 101]. The most severe effects were related to the two largest rivers:
the Vistula—1020 km long and the Odra—840 km and their upper tributaries [102,
103]. The most frequently mentioned cities located by the Vistula River that have
been affected by catastrophic floods in history are: Kraków, Sandomierz, Warszawa,
Tczew, Gda´ nsk, and Malbork [104, 105], and by Odra: Racibórz, K˛ edzierzyn-Ko´ zle,
Opole, Wrocław, Słubice, Nowa Sól, Krosno Odrza´ nskie [106, 107]. Flooded rivers
inundated urban areas located behind the river shafts numerously, and the resulting
floodplains persisted for many days. The flood in July 1997 caused 55 people to
die in Poland. About 100,000 people were evacuated at that time, and 47,000 of
residential buildings, 1,700 bridges and culverts, 71 hospitals, almost 1,000 schools
and kindergartens, 100 intakes of drinking water were flooded and damaged [108].
Cities in Poland are less and less threatened by mid-winter and spring thaw floods.
A large event of this type was in March-April 1979, due to the very intense longlasting snowfall at the turn of 1978/1979. The cities located in the Bug and Narew
basins (including Ostroł˛ eka, Pułtusk) and Warta basin (including Pozna´ n, Kalisz)
were at risk. Recently, the thaw flood occurred at the turn of February and March
2011 in the Note´ c and lower Warta catchments (Pozna´ n).
Small rivers draining cities during the mid-winter and spring thaw are not a flood
hazard, because due to the accelerated melting of the snow cover and increased
evaporation within roads, parking lots, built-up areas, etc. there is a significant loss
of water resources accumulated in the snow cover. For example, in the urbanized
catchments of Kielce, the average maximum specific runoff in March (1998–2003)