Storm Water Management in Accra, Ghana - Presentation

Storm water management

in Accra, Ghana

Heather Troutman Asiedu-Danquah

Urban water cycleProf. dr.-ing. wolfgang dickhaut

Resource efficiency in architecture and planning

Summer semester2015

June 16, 2015

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Urban water cyclesProf. dr.-ing. wolfgang dickhaut

Resource efficiency in architecture and planning 2

Table of content

General overview

Projects

Overview of the study area Climate and precipitation Storm water drainage Flood situation

Urban env’tal sanitation project-odaw drainage improvement-Korle lagoon ecological restoration project




Climate and precipitation data

Mean annual rainfall in Ghana for the period 1981 - 2010Source: Logah et. al. (2013)





Source: http://people.eku.edu/davisb/Africa/Ch5notes.htm





Source:

5




Climate and precipitation data - Return Periods

One day rainfall occurrences

June 27, 1960 98 mm

June 22, 1973 175 mm

July 14, 1991 157 mm

June 9, 2002 123mm

October 25, 2011157mm

Most Extreme one day rainfall occurrence

July 4, 1995 – 244mm

Source: https://www.modernghana.com/news/223779/1/are-the-municipal-solid-waste-management-practices.html

Source: Adopted from Okyere, Yacouba & Gilgenbach (2012)




Storm water drainage

Source: Adank et. al (2011)

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Avg. precipitation756 mm/year

Accra area1,261 km2

Avg. Storm water9.5 million m3/year




Linkages b/n hydrological, economical and political context of

flood in Accra

Source: Adopted from Okyere, Yacouba & Gilgenbach (2012)

Natural factors human factors

floods

impacts




Urbanisation & sanitation

Source: Adank et. al (2011)




flood situationJune 03, 2015

http://www.ghanaweb.com/GhanaHomePage/NewsArchive/artikel.php?ID=362491&gallery=0&VOLGNR=1

Overview of event

12 hours of rainfall

263 mm

About 35 settlements affected

150 people killed

About 9,200 people affected

http://graphic.com.gh/news/general-news/44408-annual-floods-in-accra-an-engineering-failure.html

Response

Clear debris from recent floods, as well on de-silting of choked drains

Clearing all structures in waterways

Source: UN

CT G

hana, 2015




flood situationJune 03, 2015

Actors

NADMOUNITED NATIONSInter-Agency Working Group for Emergencies (IAWGE)UNICEFWHOThe Ghana Red Cross

Source: UNCT Ghana, 2015

Suggested Long term solutions

120 km of storm drains along the major river basins

To construct water retention reservoirs

Addressing issues of waste collection and disposal




Common response

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Source: http://citifmonline.com/wp-content/uploads/2015/06/dysilting-of-odaw-river-2.jpg

Odaw river desilting

Source: http://citifmonline.com/wp-content/uploads/2015/06/dysilting-of-odaw-river-6.jpg




Source: (world bank report)

Projects

Phase 1: 1996 – 2004Dredging and lining of primary and secondary

storm drains

Phase 2: 2004 – 2007Lagoon restoration

Erosion controlConstruction of small

bridges

Urban Environmental Sanitation Project

Legal Impetus

Ghana Environmental Sanitation Policy

Ghana Poverty Reduction Strategy

United Nations Millennium Development Goals

#6: combating HIV/AIDS, malaria and other diseases

#7: ensuring environmnetal sustainability




Uesp - Odaw drainage improvement

Objective: “To alleviate flooding, the profile of the channel had to be reconstructed into a rectangular/trapezoidal shape,

so it could carry a 1:25 years flood”.

Source: (Bam International, 2014)

Under the budget of Ghana’s Urban Environmental Sanitation

Project

The Odaw Drain is the main outflow channel for Accra’s storm water drainage network in Accra.

Scope of workConstruction of a concrete-lined

channel.Length: 3.4 kilometres

Width: 23 metres Depth: 5 metres




Source: (Bam International, 2014)

Urban Environmental Sanitation Project

Uesp - Odaw drainage improvement




Impacts on Lagoons

Source: (PMI, n.d)

Pollution

About 90, 000 people living around the catchment of the lagoon

Total surface area is about 0.6 km2 and drains a total catchment area of about 400km2

The Odaw river enters the Korle lagoon and has a large concentration of industrial wastes

Korle lagoon ecological restoration project




UESPRound 2(KLERP)

Source: (PMI, n.d)

Objective: to improve Accra’s drainage, flooding and sanitation problems

Ensuring good flood waterconveyance to the sea

Implement the sewer pumpstation and offshore outfall pipeline.

4 phased project




Source: (PMI, n.d)

Phase 1

Dredging of the lagoon

Creation of storm water canals

Removal of swamps to reduce flooding

Creation of green areas

Construction of an inceptor

Construction of a pump station

Outfall installation works

Infrastructure works

Sediment removal and re- dredgingof the lagoons

Sediment removal in the canals &drains

Fencing & beautification works

Design, supervise and construct bulkservices including roads, water, sewer,storm water, drainage

To execute the required EnvironmentalImpact Assessment.

Phase 2 Phase 3 Phase 4

UESPRound 2(KLERP)




Recommendations and conclusions

Waste management solutions

Urban development solutions – creating sustainable housing

Covered drainage with pv cells

Construction of retention reserviors




Thank you!!