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GIS-based flood proneness screening:a prelude to stormwater management in rapidly urbanizing catchments

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GIS-based flood proneness screening:a prelude to stormwater management in rapidly urbanizing catchments
Absence of reliable hydro-climatic information is among the bottlenecks for inadequate and improper management of stormwater runoff in rapidly-urbanizing catchments.This paper explores the influence of catchment heterogeneity in understanding the proneness of urban catchments to stormwater-borne hazards.Using GIS techniques,satellite images,and field surveys,geomor-phological features and hydrologic characteristics of the Mbezi River catchment in Dar es Salaam-Tanzania were modeled to understand variations in their influence on flood hazards occurrence throughout the study catchment.The findings reveal that with GIS techniques public,domain Digital Elevation Models(DEMs)can provide preliminary but useful insights to inform stormwater management decisions in cities with limited hydrological data.Specifically,the heterogeneity characterization of the case study catchment indicates that Mbezi River is fem-leaf-shaped:it has a well-drained catchment(drainage density=1.9 km/km2),with total relief and elongation ratios of 265 m and 0.25,respectively.Results further revealed that the catchment is comprised of many natural sinks(blue spots)that,upon enhancement,can retain about 18 percent of stormwater runoff that could otherwise contribute to downstream runoff challenges.About 68 per-cent of the major sinks(with potential volume>2.4 m3)are located along the river flood plain where land is publicly owned.Additionally,more than 11.6 ha of land(as property)and 168 buildings.are in areas that were mapped to have large natural sinks and they are at risk to flooding when the sinks get filled.

flood risk mappingrunoff modellingflood controlrunoff routing

Given J.MHINA、Marina B.JENSEN、Thomas BALSTR?M

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Department of Environmental Science and Management,Ardhi University,Dar es Salaam B201,Tanzania

Department of Geosciences and Natural Resource Management,University of Copenhagen,Frederiksberg C 1958,Denmark

flood risk mapping runoff modelling flood control runoff routing

2025

地球科学前沿
高等教育出版社

地球科学前沿

影响因子:0.585
ISSN:2095-0195
年,卷(期):2025.19(1)