An overview of the state of practice of storm water management in Accra, Ghana with recommendations for improved management practices that go beyond top-down, centralized and very expensive western technologies, better responding to the existing functional capacity and needs of the city.

1. Storm water
management
in Accra, Ghana
Heather Troutman Asiedu-Danquah
Urban water cycle
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning
Summer semester
2015
June 16, 2015
1

2. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. 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

3. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 3
Climate and precipitation data
Mean annual rainfall in Ghana for the period 1981 - 2010
Source: Logah et. al. (2013)

4. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 4
Climate and precipitation data
Source: http://people.eku.edu/davisb/Africa/Ch5notes.htm

5. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning
Climate and precipitation data
Source:
5

6. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 6
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, 2011
157mm
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)

7. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning
Storm water drainage
Source: Adank et. al (2011)
7
Avg. precipitation
756 mm/year
Accra area
1,261 km2
Avg. Storm water
9.5 million m3
/year

8. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 8
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

9. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 9
Urbanisation & sanitation
Source: Adank et. al (2011)

10. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 10
flood situation
June 03, 2015
http://www.ghanaweb.com/GhanaHomePage/NewsArchive/artikel.php
?ID=362491&gallery=0&VOLGNR=1
Overview of event
12 hoursof rainfall
263 mm
About 35 settlementsaffected
150 peoplekilled
About 9,200 peopleaffected
http://graphic.com.gh/news/general-news/44408-annual-floods-in-accra-an-
engineering-failure.html
Response
Clear debrisfrom recent floods, aswell
on de-silting of choked drains
Clearing all structuresin waterways
Source:UNCTGhana,2015

11. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 11
flood situation
June 03, 2015
Actors
NADMO
UNITED NATIONS
Inter-Agency Working Group for
Emergencies(IAWGE)
UNICEF
WHO
TheGhanaRed Cross
Source: UNCT Ghana, 2015
Suggested Long term solutions
120 km of storm drainsalong themajor river
basins
To construct water retention reservoirs
Addressing issuesof wastecollection and
disposal

12. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning
Common response
12
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

13. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 13
Source: (world bank report)
Projects
Phase 1: 1996 – 2004
Dredging and lining of primary
and secondary storm drains
Phase 2: 2004 – 2007
Lagoon restoration
Erosion control
Construction of small bridges
Urban Environmental Sanitation Project
Legal Impetus
GhanaEnvironmental Sanitation Policy
GhanaPoverty Reduction Strategy
United NationsMillennium Development Goals
#6: combating HIV/AIDS, malariaand other
diseases
#7: ensuring environmnetal sustainability

14. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 14
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 thebudget of Ghana’sUrban
Environmental Sanitation Project
TheOdaw Drain isthemain outflow
channel for Accra’sstorm water drainage
network in Accra.
Scope of work
Construction of aconcrete-lined channel.
Length: 3.4 kilometres
Width: 23 metres
Depth: 5 metres

15. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 15
Source: (Bam International, 2014)
Urban Environmental Sanitation Project
Uesp - Odaw drainage improvement

16. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 16
Impacts on Lagoons
Source: (PMI, n.d)
 Pollution
 About 90, 000 peopleliving around the
catchment of thelagoon
 Total surfaceareaisabout 0.6 km2
and
drainsatotal catchment areaof about
400km2
 TheOdaw river enterstheKorlelagoon
and hasalargeconcentration of
industrial wastes
Korle lagoon ecological restoration project

17. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 17
UESP
Round 2(KLERP)
Source: (PMI, n.d)
Objective: to improve Accra’s drainage, flooding and sanitation problems
 Ensuring good flood water
conveyanceto thesea
 Implement thesewer pump
station and offshoreoutfall pipeline.
 4 phased project

18. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 18
Source: (PMI, n.d)
Phase 1
 Dredging of
thelagoon
 Creation of
storm water
canals
 Removal of
swampsto
reduceflooding
 Creation of
green areas
 Construction of
an inceptor
 Construction of a
pump station
 Outfall
installation works
 Infrastructure
works
 Sediment removal
and re- dredging
of thelagoons

Sediment removal
in thecanals&
drains

Fencing &
beautification
works
 Design, supervise
and construct bulk
servicesincluding
roads, water,
sewer,
storm water,
drainage
 To executethe
required
Environmental
Impact
Assessment.
Phase 2 Phase 3 Phase 4
UESP
Round 2(KLERP)

19. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 19
Recommendations and
conclusions
 Waste management solutions
 Urban development solutions – creating sustainable housing
 Covered drainage with pv cells
 Construction of retention reserviors

20. Heather Troutman Asiedu-Danquah
Urban water cycles
Prof. dr.-ing. wolfgang dickhaut
Resource efficiency in architecture and planning 20
Thank you!!