Flood hazard response to scenarios of rainfall dynamics and land use and land cover change in an urbanized river basin in Accra, Ghana

Understanding of flood hazard response to multiple scenarios of relevant determinants in urban centers is a precondition for proactive disaster risk management. Yet, studies on flood response to the effects of multiple agents in Sub-Saharan Africa countries is rare. This study simulates peak runoff...

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Autores principales:	Opoku Pabi, Sylvester Egyir, Emmanuel Morgan Attua
Formato:	article
Lenguaje:	EN
Publicado:	Elsevier 2021
Materias:	Flood hazard Urbanization Odaw River Basin Land use and Land cover change Rainfall intensity Flow Rate Environmental sciences GE1-350 Urban groups. The city. Urban sociology HT101-395
Acceso en línea:	https://doaj.org/article/a05d4194a8fe4ab78a34a0d2090e5c15
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spelling	oai:doaj.org-article:a05d4194a8fe4ab78a34a0d2090e5c152021-11-18T04:51:30ZFlood hazard response to scenarios of rainfall dynamics and land use and land cover change in an urbanized river basin in Accra, Ghana2590-252010.1016/j.cacint.2021.100075https://doaj.org/article/a05d4194a8fe4ab78a34a0d2090e5c152021-12-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S2590252021000209https://doaj.org/toc/2590-2520Understanding of flood hazard response to multiple scenarios of relevant determinants in urban centers is a precondition for proactive disaster risk management. Yet, studies on flood response to the effects of multiple agents in Sub-Saharan Africa countries is rare. This study simulates peak runoff and water flow rate to land use and land cover (LULC), and scenarios of rainfall intensity of different durations and return periods. An urban flood-prone Odaw River catchment of Accra, Ghana was studied for the possible hazard responses to variations in LULC and rainfall intensities and amounts. Landsat data for 2000, 2011 and 2020 were classified and analyzed for changes in LULC. Rainfall intensity was estimated for different durations; and 2, 10 and 25 years of return periods, using Intensity-Duration-Frequency (IDF) model. The rational and the successive flow routing hydrological models were used to simulate peak runoff and flow rate, respectively. Built-up area increased in coverage from 40% in 2000 to 65% in 2020, whereas woodland reduced from 10.5% to 4.0% for the same period. The peak runoff was highest in the built-up areas, and directly proportional to rainfall intensities and return periods. Replacing a given amount of woodland by equal amount of built-up area increased peak discharge by 3.5 times. Runoff peaked 30 mins after onset of rainfall for the 10-yr and 25-yr return periods, but peaked 1 hr for the 2-yr return period. We recommend that flood risk reduction strategies maintain substantial amount of woody vegetation and grassland, and provide quick early warning when extremely high rainfall intensity is anticipated. Land use planning organization should consider a range of flood hazard intensities, including rare and extreme events in their decisions.Opoku PabiSylvester EgyirEmmanuel Morgan AttuaElsevierarticleFlood hazardUrbanizationOdaw River BasinLand use and Land cover changeRainfall intensityFlow RateEnvironmental sciencesGE1-350Urban groups. The city. Urban sociologyHT101-395ENCity and Environment Interactions, Vol 12, Iss , Pp 100075- (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Flood hazard Urbanization Odaw River Basin Land use and Land cover change Rainfall intensity Flow Rate Environmental sciences GE1-350 Urban groups. The city. Urban sociology HT101-395
spellingShingle	Flood hazard Urbanization Odaw River Basin Land use and Land cover change Rainfall intensity Flow Rate Environmental sciences GE1-350 Urban groups. The city. Urban sociology HT101-395 Opoku Pabi Sylvester Egyir Emmanuel Morgan Attua Flood hazard response to scenarios of rainfall dynamics and land use and land cover change in an urbanized river basin in Accra, Ghana
description	Understanding of flood hazard response to multiple scenarios of relevant determinants in urban centers is a precondition for proactive disaster risk management. Yet, studies on flood response to the effects of multiple agents in Sub-Saharan Africa countries is rare. This study simulates peak runoff and water flow rate to land use and land cover (LULC), and scenarios of rainfall intensity of different durations and return periods. An urban flood-prone Odaw River catchment of Accra, Ghana was studied for the possible hazard responses to variations in LULC and rainfall intensities and amounts. Landsat data for 2000, 2011 and 2020 were classified and analyzed for changes in LULC. Rainfall intensity was estimated for different durations; and 2, 10 and 25 years of return periods, using Intensity-Duration-Frequency (IDF) model. The rational and the successive flow routing hydrological models were used to simulate peak runoff and flow rate, respectively. Built-up area increased in coverage from 40% in 2000 to 65% in 2020, whereas woodland reduced from 10.5% to 4.0% for the same period. The peak runoff was highest in the built-up areas, and directly proportional to rainfall intensities and return periods. Replacing a given amount of woodland by equal amount of built-up area increased peak discharge by 3.5 times. Runoff peaked 30 mins after onset of rainfall for the 10-yr and 25-yr return periods, but peaked 1 hr for the 2-yr return period. We recommend that flood risk reduction strategies maintain substantial amount of woody vegetation and grassland, and provide quick early warning when extremely high rainfall intensity is anticipated. Land use planning organization should consider a range of flood hazard intensities, including rare and extreme events in their decisions.
format	article
author	Opoku Pabi Sylvester Egyir Emmanuel Morgan Attua
author_facet	Opoku Pabi Sylvester Egyir Emmanuel Morgan Attua
author_sort	Opoku Pabi
title	Flood hazard response to scenarios of rainfall dynamics and land use and land cover change in an urbanized river basin in Accra, Ghana
title_short	Flood hazard response to scenarios of rainfall dynamics and land use and land cover change in an urbanized river basin in Accra, Ghana
title_full	Flood hazard response to scenarios of rainfall dynamics and land use and land cover change in an urbanized river basin in Accra, Ghana
title_fullStr	Flood hazard response to scenarios of rainfall dynamics and land use and land cover change in an urbanized river basin in Accra, Ghana
title_full_unstemmed	Flood hazard response to scenarios of rainfall dynamics and land use and land cover change in an urbanized river basin in Accra, Ghana
title_sort	flood hazard response to scenarios of rainfall dynamics and land use and land cover change in an urbanized river basin in accra, ghana
publisher	Elsevier
publishDate	2021
url	https://doaj.org/article/a05d4194a8fe4ab78a34a0d2090e5c15
work_keys_str_mv	AT opokupabi floodhazardresponsetoscenariosofrainfalldynamicsandlanduseandlandcoverchangeinanurbanizedriverbasininaccraghana AT sylvesteregyir floodhazardresponsetoscenariosofrainfalldynamicsandlanduseandlandcoverchangeinanurbanizedriverbasininaccraghana AT emmanuelmorganattua floodhazardresponsetoscenariosofrainfalldynamicsandlanduseandlandcoverchangeinanurbanizedriverbasininaccraghana
_version_	1718424995190800384

Flood hazard response to scenarios of rainfall dynamics and land use and land cover change in an urbanized river basin in Accra, Ghana

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