Urbanization impacts upon catchment hydrology and gully development using mutli‐temporal digital elevation data analysis

Abstract

Urbanization can change catchment hydrology, accelerating gully erosion and causing serious damage to urban structures like roads, bridges and buildings. Increased impervious surfaces lead to large, rapid increases in surface runoff in urban catchments during storm events, as well as changes in the upslope contributing area due to rerouting of urban runoff that can exacerbate erosion. Accounting for changes in surface drainage patterns Gama City, Brazil, is used to predict areas prone to accelerate gullying and develop a method of assessing the potential for gully erosion produced by urbanization. The method is based on the analysis and comparison of detailed digital elevation models (DEMs) of the natural condition before urbanization and the topography after urbanization. The study site is located in an area where changes in drainage patterns associated with rapid urbanization in the last 30 years have resulted in severe gullying. Our analysis identifi es areas potentially susceptible to gullying and highlights the erosional infl uence of increased fl ow concentration caused by urban occupation, a fi nding that has implications and applications for strategies to prevent gully development in cities or areas undergoing urban expansion. Copyright

Urban gully erosion in sub‐Saharan Africa: A case study from Uganda

“…Makanzu Imwangana et al (, ) documented the extensive occurrence of mega‐gullies in the high town of Kinshasa, Congo DR, causing extensive damage to urban infrastructure and propagating water and sediment problems farther downstream. Analogous phenomena have been observed in expanding urban areas of Brazil (Junior et al, ). Although the physical processes leading to gully initiation and evolution do not essentially differ between urban and rural areas, the controls on urban gully development are closely related to man‐made alteration of the natural drainage network associated with roads construction (Adediji et al, ).…”

“…Despite gully systems often represent a quantitatively relevant source of eroded sediments within a catchment, studies on gully erosion are quite limited when compared to those addressing sheet or rill erosion of soil by water (Poesen, Torri, & Vanwalleghem, ). Furthermore, gully erosion occurring in urban areas has received much less attention compared to rural and agricultural areas (e.g., Junior et al, , Makanzu Imwangana, Dewitte, Ntombi, & Moeyersons, ), despite its societal relevance. Moreover, most existing urban gully erosion studies focus on characterizing gully properties and dynamics at local scales, whereas they pose less attention to the design of mitigation measures and their sustainability and to the possible implications at larger spatial scales.…”

Spatial–temporal evolution of the distribution pattern of river systems in the plain river network region of the Taihu Basin, China

“…These changes have strongly threatened the ecological integrity and ecosystem functions of river systems (Dudgeon, 2006). Thus, an increasing need to investigate the impacts of urbanization on river systems for the sustainable planning, management and conservation of rapidly urbanized river basins has been realized (Karr, 1999;Norris and Thoms, 1999;James and Marcus, 2006;Junior et al, 2010;Pinto and Maheshwari, 2011).…”

Impacts of Urbanization on River Systems in the Taihu Region, China

“…The studies of the impacts of urbanization on river systems have made significant progress over the past 60 years, and these advances have been focusing mainly on rapidly urbanized regions around the world [9]. Overall, the impacts of urbanization on river systems were mainly embodied in the fluvial geomorphology, hydrology and ecology, but the impacts were inconsistent for river systems of different stream orders and human needs [10][11][12]. Generally, main rivers of a high stream order were widened because of the increase of the runoff volume caused by river channel dredging and impervious surface increases, and tributaries of a low stream order were narrowed gradually or even disappeared because of river channel sedimentation and urban occupation [13][14][15].…”