262
M. Gor˛ aczko
Brzeg, Głogów, Słubice, Kostrzy´ n, and Szczecin. In the same period, measurements
began on Warta River – in Gorzów Wielkopolski (1809) and Pozna´ n (1818) and
Note´ c River in Drezdenko (1811). These, however, are exceptions, as the overall
history of a systematic measuring of water levels of Polish rivers rarely goes back
more than 200 years. For example, the first measurements on Podkarpacie rivers such
as San, Raba, Dunajec, Wisłoka and Wisłok were made in 1887. Stream gauges on
rivers such as Bzura, Drw˛ eca, Wierzyca, Rega, Pars˛ eta, Słupia, Pasł˛ eka and Łyna
appeared only in the twentieth century [22]. Effectively, the current knowledge about
floods that occurred in the country prior to the late nineteenth century comes from
annals, lexicons, administrative documents, newspapers and other archives, i.e. [29–
31]. The main flaw of these records is that they lack the precise measurements of the
flood wave, consequently lacking the precise indication of the range of the floods.
This is exactly where high watermarks provide an exception, as by marking the
maximum levels of historical floods, they manage to provide a valuable reference
to assess the possibilities of high water rises in the area in regards to the current
conditions of the terrain. Placing high watermarks has value even today, despite the
existence of over 800 hydrological stations throughout the country [32] and the great
progress made in the last 20 years, in fields of methodology and technology of hydrological measurement. It is significant in spite of the developments in interpretation
and implementation of the obtained data (use of the modern measurement tools,
development of aerial and satellite terrain mapping, advancement of hydrological
modeling, creation of flood risk maps etc.). High watermarks placed along the river
flows, amongst the controlling bed cross-section, allows a credible verification of
flood forecasting.
Where placed in an open public spaces, high watermarks can bring awareness
to the potential threats posed by floods. By displaying the level once reached by
the water, they serve as a valuable referential for the entire surrounding terrain and
the structures existing within it. This is particularly significant on the areas directly
next to the river embankment. In modern times, due to the progressive process of
suburbanisation, these areas are commonly being transformed from farmlands into
residential zones. The new inhabitants of these terrains are rarely aware of the risks
they had taken by moving into the vicinity of the river, perceiving it as a mere attraction of the landscape. Some citizens place excessive trust into the flood protection
walls, even though the conclusion coming from the larger floods that occurred in
modern times in Poland is unequivocal that the efficiency of any technology and
methods for flood protection diminishes proportionally to the increase of the levels
of the water and duration of the increased water flow. It can even be concluded that
the existence of the flood barriers leads many into a false sense of security. Therefore, sharing the knowledge about the existence of high watermarks, especially in
schools is very important. Maintaining their good technical and aesthetic condition,
and even erecting new objects of that type immediately after an occurrence of a
maximum flood ought to be elements of the fundamental flood-protection education
in the given localities. Involvement in such actions is in the very interest of the local
population.
M. Gor˛ aczko
Brzeg, Głogów, Słubice, Kostrzy´ n, and Szczecin. In the same period, measurements
began on Warta River – in Gorzów Wielkopolski (1809) and Pozna´ n (1818) and
Note´ c River in Drezdenko (1811). These, however, are exceptions, as the overall
history of a systematic measuring of water levels of Polish rivers rarely goes back
more than 200 years. For example, the first measurements on Podkarpacie rivers such
as San, Raba, Dunajec, Wisłoka and Wisłok were made in 1887. Stream gauges on
rivers such as Bzura, Drw˛ eca, Wierzyca, Rega, Pars˛ eta, Słupia, Pasł˛ eka and Łyna
appeared only in the twentieth century [22]. Effectively, the current knowledge about
floods that occurred in the country prior to the late nineteenth century comes from
annals, lexicons, administrative documents, newspapers and other archives, i.e. [29–
31]. The main flaw of these records is that they lack the precise measurements of the
flood wave, consequently lacking the precise indication of the range of the floods.
This is exactly where high watermarks provide an exception, as by marking the
maximum levels of historical floods, they manage to provide a valuable reference
to assess the possibilities of high water rises in the area in regards to the current
conditions of the terrain. Placing high watermarks has value even today, despite the
existence of over 800 hydrological stations throughout the country [32] and the great
progress made in the last 20 years, in fields of methodology and technology of hydrological measurement. It is significant in spite of the developments in interpretation
and implementation of the obtained data (use of the modern measurement tools,
development of aerial and satellite terrain mapping, advancement of hydrological
modeling, creation of flood risk maps etc.). High watermarks placed along the river
flows, amongst the controlling bed cross-section, allows a credible verification of
flood forecasting.
Where placed in an open public spaces, high watermarks can bring awareness
to the potential threats posed by floods. By displaying the level once reached by
the water, they serve as a valuable referential for the entire surrounding terrain and
the structures existing within it. This is particularly significant on the areas directly
next to the river embankment. In modern times, due to the progressive process of
suburbanisation, these areas are commonly being transformed from farmlands into
residential zones. The new inhabitants of these terrains are rarely aware of the risks
they had taken by moving into the vicinity of the river, perceiving it as a mere attraction of the landscape. Some citizens place excessive trust into the flood protection
walls, even though the conclusion coming from the larger floods that occurred in
modern times in Poland is unequivocal that the efficiency of any technology and
methods for flood protection diminishes proportionally to the increase of the levels
of the water and duration of the increased water flow. It can even be concluded that
the existence of the flood barriers leads many into a false sense of security. Therefore, sharing the knowledge about the existence of high watermarks, especially in
schools is very important. Maintaining their good technical and aesthetic condition,
and even erecting new objects of that type immediately after an occurrence of a
maximum flood ought to be elements of the fundamental flood-protection education
in the given localities. Involvement in such actions is in the very interest of the local
population.