430
R. Graf and K. Pyszny
reduction of the active biological area and the so-called sprawl of building development (the development of housing), also in the vicinity of environmentally valuable areas. Presently registered climate changes cause the ever more frequent occurrence of extreme weather phenomena, such as drought and torrential precipitation.
Approximately 38% of the territory of Poland is affected by drought and the excessive exploitation of water resources [6]. The connection of these changes with an
increase in urbanisation is associated among others with the problem of rainwater
retention in cities, its appropriate management and utilisation in periods of resource
shortages, and also with the necessity of collecting, treating and reusing municipal
sewage. The surface run-off generated in cities in consequence of intense precipitation is usually channelled away through storm sewage systems to surface waters or
storage (detention) reservoirs, which constitute an element of cities with a sustainable rainwater management system [18–21]. In the case of cities it is assumed that
approximately 90–100% of precipitation is channelled away directly to rainwater
receptacles, whereas on areas with single-family housing nearly one half of precipitation is discharged directly to a receptacle, with the remainder shaping ground
run-off [22–26]. By speeding up the flow of precipitation to rivers, the municipal
rainwater sewage system frequently brings about an increase in the flood hazard,
however in areas with a low infiltration capacity its action may limit the risk of
occurrence of local small-scale flooding.
Polish cities often lack storage reservoirs that would halt and collect rainwater,
and thus the problem in question is analysed in terms of increasing the share of
biologically active zones in the city structure [27, 28]. Through the intensification of
rainwater retention and infiltration processes and the concomitant slowing down of
water outflow, these areas contribute to the stabilisation of water circulation conditions in catchment areas with a high index of development. In municipal areas,
the concept of rainwater management is implemented among others by the utilisation of Low Impact Development (LID), Water Sensitive Urban Design (WSUD),
and Sustainable Urban Drainage Systems (SUDS) [29]. Depending on the nature of
urban space, priority is given to actions contributing to an increase in green areas
within fixed properties, e.g. the erection of green roofs, the setting up of local small
ponds or the construction of car parks. These activities facilitates rainwater development and limits the need for channeling precipitation away through rainwater
sewage systems. The sustainable utilisation of water resources in metropolises is
made possible by comprehensive surface water management systems which enable
the pro-environmental and economic reutilisation of water, and thereby water security
management for both man and the natural environment.
R. Graf and K. Pyszny
reduction of the active biological area and the so-called sprawl of building development (the development of housing), also in the vicinity of environmentally valuable areas. Presently registered climate changes cause the ever more frequent occurrence of extreme weather phenomena, such as drought and torrential precipitation.
Approximately 38% of the territory of Poland is affected by drought and the excessive exploitation of water resources [6]. The connection of these changes with an
increase in urbanisation is associated among others with the problem of rainwater
retention in cities, its appropriate management and utilisation in periods of resource
shortages, and also with the necessity of collecting, treating and reusing municipal
sewage. The surface run-off generated in cities in consequence of intense precipitation is usually channelled away through storm sewage systems to surface waters or
storage (detention) reservoirs, which constitute an element of cities with a sustainable rainwater management system [18–21]. In the case of cities it is assumed that
approximately 90–100% of precipitation is channelled away directly to rainwater
receptacles, whereas on areas with single-family housing nearly one half of precipitation is discharged directly to a receptacle, with the remainder shaping ground
run-off [22–26]. By speeding up the flow of precipitation to rivers, the municipal
rainwater sewage system frequently brings about an increase in the flood hazard,
however in areas with a low infiltration capacity its action may limit the risk of
occurrence of local small-scale flooding.
Polish cities often lack storage reservoirs that would halt and collect rainwater,
and thus the problem in question is analysed in terms of increasing the share of
biologically active zones in the city structure [27, 28]. Through the intensification of
rainwater retention and infiltration processes and the concomitant slowing down of
water outflow, these areas contribute to the stabilisation of water circulation conditions in catchment areas with a high index of development. In municipal areas,
the concept of rainwater management is implemented among others by the utilisation of Low Impact Development (LID), Water Sensitive Urban Design (WSUD),
and Sustainable Urban Drainage Systems (SUDS) [29]. Depending on the nature of
urban space, priority is given to actions contributing to an increase in green areas
within fixed properties, e.g. the erection of green roofs, the setting up of local small
ponds or the construction of car parks. These activities facilitates rainwater development and limits the need for channeling precipitation away through rainwater
sewage systems. The sustainable utilisation of water resources in metropolises is
made possible by comprehensive surface water management systems which enable
the pro-environmental and economic reutilisation of water, and thereby water security
management for both man and the natural environment.