With a current population growth rate of 2% per year in Lomma, Lund and Staffanstorp and a total anticipated increase of 11% from 2010 to 2017, there is high pressure to provide additional residential and commercial space in existing urban areas (County Administrative Board of Skåne, 2009).
SUSANNAH FLOOD BRA SIZE SERIES
Although the rainfall triggered the flooding, its extensive impact was exacerbated by a series of landscape attributes resulting from agricultural drainage and urbanisation. The event became a turning point in how future storm water policies should be devised, with the establishment of a trans-municipal water authority (Höjeå Water Council, 2012). All three municipalities suffered major financial losses owing to damage to property and infrastructure. In summer 2007, prolonged periods of heavy rain caused extensive flooding within the catchment area. Within the heavily urbanised region of southern Sweden, the municipalities of Lomma, Lund and Staffanstorp constitute the three major conurbations in the 316 km 2 Höjeå river catchment, before the river reaches its outlet in the Öresund Sea (Fig. Department of Agriculture Soil Conservation Services (SCS-CN) (now the USDA Natural Resources Conservation Service (USDA NRCS) (SCS, 1972), having become a well-recognised tool in research and landscape planning world-wide (e.g. Different methods and models for examining this effect are now available, with the curve number approach originally developed by the U.S.
The specific effects of land cover changes in increasing surface runoff have also been covered by e.g. The role of residential areas in terms of green infrastructure benefits and a range of ecosystem services have been explored in a number of research studies (e.g. the UK constituting between 35 and 47% of the total urban green space (Goddard et al., 2009). World-wide, residential areas make up a large proportion of the urban landscape, with domestic gardens in e.g. This runoff originates from both public and private land. (2011) reported that urban landscapes with an impermeable land cover of 50–90% can generate 40–83% surface runoff from a given rainfall event. In a recent review on urban green space, Pataki et al. The effect of this development pattern is an increase in surface runoff, which often leads to unpredicted pluvial flooding in areas outside recognised river floodplains (RIBA, 2011). Floods are also strongly related to the increased area of impermeable surfaces in the urbanised landscape, where settlements and urbanisation form a solid impervious barrier in the hydrological system. Flooding can take place following extreme weather events, such as prolonged periods of precipitation or short and intense rainstorms. Water has its routes and trails through urban and rural landscapes and when flooding occurs, people experience the hydrological cycle, often with detrimental effects on property, infrastructure, businesses, and human health and well-being (Reacher et al., 2004). However, adapting a systems approach in combining vegetative structures and permeable paving materials with subsurface infiltration beds can help mitigate the impact of surface runoff, particularly in urban developments on clay-rich soils. Increased area of impermeable surface cover will increase surface runoff in all residential areas, irrespective of building density, soil group and rainfall intensity. conserving existing vegetated surfaces on sandy soil and incorporating permeable paving materials and sub-surface infiltration beds in development on clayey soils. It may therefore be appropriate to apply different planning considerations to residential developments depending on the existing soil group, e.g. A similar pattern is likely to occur if rainfall intensity increases. However, increasing the density of built-up areas on sandy soils is likely to be more disruptive to the hydrological balance and to generate a greatly increasing difference in runoff as building density and impermeable surface area increase. The results indicated that identical amounts of surface runoff are generated by low-density residential areas on heavy clay soils and high-density residential areas on sandy soils. The Soil Conservation Service curve number (SCS-CN) method was applied to analyse urban development in the Höjeå river catchment in southern Sweden. This study examined these contributions and the associated effect of different surface covers and sustainable drainage systems on runoff generation. Depending on the spatial density of built cover and location within a catchment, residential areas make varying contributions to surface runoff throughout different rainfall events.
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