18 The Multidimensional Aspect of Water Resources …
443
actions is assumed in the case of “internal” communes, that is ones located in the
central part of the Pozna´ n metropolis (Fig. 18.5), than in communes situated in
the “boundary zone”, which additionally neighbour on communes from outside the
metropolitan area.
18.4.5 Flood Risk and Rainwater Management
Management of the space comprising the metropolitan area requires the establishment of safe living conditions, the provision of protection against floods and their
effects, protection against local small-scale flooding and the inflow of pollution, and
also the regulation of microclimatic conditions. Implementation within the Pozna´ n
metropolis of the objectives of the so-called Flood Directive, i.e. on the assessment
and management of flood risks [35], should take into consideration the reach of flood
risk zones and the scale of flood risk, together with a designation of the protective
function.
Within the metropolis, areas threatened by flooding with a probability of occurrence of 1% (once every 100 hundred years) include those situated in the River
Warta Valley along the following sections (Fig. 18.6): the Pozna´ n Warta Gorge
(between ´
Srem and Oborniki), the Obornicka Valley of the Warta (below Oborniki),
and partially above ´
Srem (source: Hydroportal, Polish Water State Water Holding).
In the directions of spatial development of the metropolis, areas exposed to flood
risk should be excluded from development or classified as land with special conditions
of building development and utilisation. The nature of actions connected with flood
risk management in the metropolis has been specified in the “Flood Risk Management
Plan for the Drainage Basin of the River Odra”, which was implemented in 2016. The
catalogue of primary objectives of flood risk management in the drainage basin takes
into consideration groups of both technical and non-technical actions connected with:
halting the increase of flood risk, minimising the existing flood risk, and improving
the system of flood risk management [52]. Within the area covered by the present
study, these actions concern the entire River Warta Valley along the section between
´
Srem and Oborniki, and the catchment area of the River Sama (commune of Szamotuły), the River Mała Wełna (commune of Skoki), and the River Cybina (commune of
Swarz˛ edz)—Fig. 18.6. The minimisation of flood risk in the metropolitan area can be
attained through the implementation of a cohesive programme targeted at changing
the method of usage of the river valleys of the Warta and its tributaries. This should
contribute to reducing susceptibility and exposure, and also the sensitivity of development and society to floods, as well as other extreme phenomena, for example
drought. Limiting the area’s exposure to floods by determining opportunities for the
utilisation of floodlands in a manner insusceptible to the effects of flooding (e.g.
parks, recreational areas) constitutes an alternative (ecological) method of providing
a system of technical flood protection, which usually has a negative impact on the
state of the natural environment. Spatial analyses of components of the hydrological
balance in urbanised catchment areas of the Pozna´ n metropolis have demonstrated,
443
actions is assumed in the case of “internal” communes, that is ones located in the
central part of the Pozna´ n metropolis (Fig. 18.5), than in communes situated in
the “boundary zone”, which additionally neighbour on communes from outside the
metropolitan area.
18.4.5 Flood Risk and Rainwater Management
Management of the space comprising the metropolitan area requires the establishment of safe living conditions, the provision of protection against floods and their
effects, protection against local small-scale flooding and the inflow of pollution, and
also the regulation of microclimatic conditions. Implementation within the Pozna´ n
metropolis of the objectives of the so-called Flood Directive, i.e. on the assessment
and management of flood risks [35], should take into consideration the reach of flood
risk zones and the scale of flood risk, together with a designation of the protective
function.
Within the metropolis, areas threatened by flooding with a probability of occurrence of 1% (once every 100 hundred years) include those situated in the River
Warta Valley along the following sections (Fig. 18.6): the Pozna´ n Warta Gorge
(between ´
Srem and Oborniki), the Obornicka Valley of the Warta (below Oborniki),
and partially above ´
Srem (source: Hydroportal, Polish Water State Water Holding).
In the directions of spatial development of the metropolis, areas exposed to flood
risk should be excluded from development or classified as land with special conditions
of building development and utilisation. The nature of actions connected with flood
risk management in the metropolis has been specified in the “Flood Risk Management
Plan for the Drainage Basin of the River Odra”, which was implemented in 2016. The
catalogue of primary objectives of flood risk management in the drainage basin takes
into consideration groups of both technical and non-technical actions connected with:
halting the increase of flood risk, minimising the existing flood risk, and improving
the system of flood risk management [52]. Within the area covered by the present
study, these actions concern the entire River Warta Valley along the section between
´
Srem and Oborniki, and the catchment area of the River Sama (commune of Szamotuły), the River Mała Wełna (commune of Skoki), and the River Cybina (commune of
Swarz˛ edz)—Fig. 18.6. The minimisation of flood risk in the metropolitan area can be
attained through the implementation of a cohesive programme targeted at changing
the method of usage of the river valleys of the Warta and its tributaries. This should
contribute to reducing susceptibility and exposure, and also the sensitivity of development and society to floods, as well as other extreme phenomena, for example
drought. Limiting the area’s exposure to floods by determining opportunities for the
utilisation of floodlands in a manner insusceptible to the effects of flooding (e.g.
parks, recreational areas) constitutes an alternative (ecological) method of providing
a system of technical flood protection, which usually has a negative impact on the
state of the natural environment. Spatial analyses of components of the hydrological
balance in urbanised catchment areas of the Pozna´ n metropolis have demonstrated,