444
R. Graf and K. Pyszny
particularly in the city’s centre, the low share of zones where the process of rainwater
retention and infiltration is dominant; such zones shape the quantity of run-off and the
volume of groundwater resources [53–55]. As regards maintaining the equilibrium
of the hydrological balance in the municipal system, both impermeable surfaces,
which in the main generate surface run-off and valley-like drainage zones, which
may contribute to local increases in evapotranspiration, are equally unfavourable.
The share of surface run-off in the structure of the hydrological balance of municipal
catchment areas is approximately 10%, while in catchment areas with a high degree of
urbanisation (e.g. Bogdanka, Potok Junikowski) it rises to as much as 18%. This value
is higher than that measured for the catchment areas of tributaries of the River Warta
located outside the city, where surface run-off accounts for approximately 5–6% of
precipitation [53, 54]. The greatest surface run-off (>150–200 mm) is generated by
catchment areas with a degree of urbanisation of 40–60%, where the considerable
compactness of development may contribute to an increase in the risk of occurrence
of small-scale flooding at points of accumulation of water run-off [55]. The proper
management of water resources in the metropolitan area through the biotechnical
method of development of precipitation water, afforestation, or limiting the sealing
of surfaces of urbanised areas (e.g. green car parks) will exert a significant impact on
increasing the biologically active surface, which regulates the state of surface waters
and groundwaters in municipal catchment areas. As regards ensuring the security
and protection against the effects of extreme climatic and hydrological phenomena
in the context of the Pozna´ n agglomeration, it would appear advantageous to bring
about the integration of actions of many subjects on numerous planes, e.g. the spatial
and functional.
18.5 Summary and Conclusion
The integration of the water resources management system in the metropolitan
area is connected with the coordination of activities not only on the spatial and
functional levels but also on the social and environmental. Integrated management
of the metropolitan area is based on three pillars: equal access to a high-quality
natural environment, the efficient utilisation of natural resources in order to achieve
economic advantages, and maintaining the ecological equilibrium and the ability
of the natural system to regenerate. Identified problems connected with the risk of
non-attainment of environmental objectives, increasing pressure on existing water
resources, and flood risk make it necessary to ensure high standards of spatial development in metropolises. This requires taking into account the taking into consideration of an interdisciplinary approach, multisectoral and long-term planning, and the
broad cooperation of various groups of stakeholders, all the more so as the decided
majority of metropolitan functions are located in Pozna´ n [45]. An improvement of
the quality of management in the field of water resources in the metropolitan system
also requires the competent support of the authorities and necessitates the elaboration
and adoption of common principles of water resources management for a common
R. Graf and K. Pyszny
particularly in the city’s centre, the low share of zones where the process of rainwater
retention and infiltration is dominant; such zones shape the quantity of run-off and the
volume of groundwater resources [53–55]. As regards maintaining the equilibrium
of the hydrological balance in the municipal system, both impermeable surfaces,
which in the main generate surface run-off and valley-like drainage zones, which
may contribute to local increases in evapotranspiration, are equally unfavourable.
The share of surface run-off in the structure of the hydrological balance of municipal
catchment areas is approximately 10%, while in catchment areas with a high degree of
urbanisation (e.g. Bogdanka, Potok Junikowski) it rises to as much as 18%. This value
is higher than that measured for the catchment areas of tributaries of the River Warta
located outside the city, where surface run-off accounts for approximately 5–6% of
precipitation [53, 54]. The greatest surface run-off (>150–200 mm) is generated by
catchment areas with a degree of urbanisation of 40–60%, where the considerable
compactness of development may contribute to an increase in the risk of occurrence
of small-scale flooding at points of accumulation of water run-off [55]. The proper
management of water resources in the metropolitan area through the biotechnical
method of development of precipitation water, afforestation, or limiting the sealing
of surfaces of urbanised areas (e.g. green car parks) will exert a significant impact on
increasing the biologically active surface, which regulates the state of surface waters
and groundwaters in municipal catchment areas. As regards ensuring the security
and protection against the effects of extreme climatic and hydrological phenomena
in the context of the Pozna´ n agglomeration, it would appear advantageous to bring
about the integration of actions of many subjects on numerous planes, e.g. the spatial
and functional.
18.5 Summary and Conclusion
The integration of the water resources management system in the metropolitan
area is connected with the coordination of activities not only on the spatial and
functional levels but also on the social and environmental. Integrated management
of the metropolitan area is based on three pillars: equal access to a high-quality
natural environment, the efficient utilisation of natural resources in order to achieve
economic advantages, and maintaining the ecological equilibrium and the ability
of the natural system to regenerate. Identified problems connected with the risk of
non-attainment of environmental objectives, increasing pressure on existing water
resources, and flood risk make it necessary to ensure high standards of spatial development in metropolises. This requires taking into account the taking into consideration of an interdisciplinary approach, multisectoral and long-term planning, and the
broad cooperation of various groups of stakeholders, all the more so as the decided
majority of metropolitan functions are located in Pozna´ n [45]. An improvement of
the quality of management in the field of water resources in the metropolitan system
also requires the competent support of the authorities and necessitates the elaboration
and adoption of common principles of water resources management for a common