The Accra Metropolitan Area (AMA) is suffering from a major urban infrastructure gap. The region’s increasing economic growth has triggered rapid urbanization, characterized by expansion of built-up environment – roads, parking lots, and other structures with impervious surfaces that do not allow water to infiltrate easily so as to replenish the water table.

1. EminentPanelConference,Accra,August7th -9th,2020
PRELIMINARY FINDINGS:
Cost-benefit analysis of the urbanisation
challenges in Accra, Ghana
Martin Oteng-Ababio,
Department of Geography and Resource Development, University of
Ghana

2. • Accra Metropolitan Assembly economic growth, increasing urbanisation and
infrastructural development conundrum
- Gt. Accra hosts 20% of Ghana’s pop and contributes 25% to GDP
- Urbanisation rate – 36% (1990); 55% (2010); and projected to 63.4% (2030)
- Infrastructural development to GDP– Ghana (2%); India (5.2%); China (8.8%)
• Some key challenges emerging –
- Rapid, unplanned growth – 70% people live in un-serviced slums (20% in Odaw catchment)
- Expansion of impervious surfaces and increasing runoffs
- Inadequate drainage systems and/or insufficient design capacities downstream
- Increasing volume and content of waste with less than 65% collection rate
• Decreased drainage containment capacity due to siltation, waste piling up and lack of
maintenace leads to perenial flooding of Accra with dire consequences – economic,
social, environmental, etc
Background informatiom

3. Perennial flooding and government interventions
• June 3, 2015 “Twin-disaster” (when flood
water caught fire at Circle)
• Social cost – 256 death
• Social cost - affected 53,000 people;
• Economic cost - losses amounted to US$55
million,
• Economic cost - reconstruction cost of US$105
million
• Most policy initiatives appear adhoc due
to inadequate funding, limited public
support, political liability; etc
• Over-concentration of desilting (dredging)
of Odaw channel at huge cost has yielded
limited dividends

4. Description of Interventions
1. Establish Retention Ponds
* Establish / rehabilitate two retention ponds in Patang and Haatso, BCR = 1.3
2. Storm Drain Widening
* Large storm drain (13.5km) in western part of Accra through Kissieman,
Dome and Taifa that discharges into the Caprice-Alajo drain, BCR = 1.8
3. Community Solid Waste Management
* Entrust a private entity with full responsibility within a given ‘camp based on
project done in Jamestown, Accra in 2014, BCR= 1.1

5. Intervention 1
Establish Retention ponds in Accra

6. Retention ponds
• Two additional retention ponds:
• Pantang retention pond
• 9ha
• 180,000 m3 capability at 2m depth
• Some encroachment into space from
squatters
• Haatso retention pond
• 8.1ha
• 162,000 m3 capability
• Private land

7. The cost to establish both retention ponds is 222m cedi –
largest cost is the nuisance cost of smell and mosquitos
Key assumptions for costs
• Retention pond cost 5.1 cedi/m3 capacity (Aerts,
2018)
• Land cost 13.7m for both ponds
• Relocation cost of squatters 2m cedi for Pantang
pond
Ongoing costs
• 10% maintenance cost on retention pond
investment (Aerts, 2018)
• Annual surveillance cost 50,000 cedi/pond/year to
prevent further encroachment
• Nuisance cost is estimated at 9m cedi/year/pond
• Communication cost 650,000 cedi/year
Nuisance
(smell,
mosquitos)
74%
Land
5%
Establishme
nt and
relocation
1%
Ongoing
20%
Costs to establish two retention
ponds (undiscounted)

8. Benefits: Two retention ponds would increase
flood mitigation benefits of GARID by 20%
GARID
• $200m spending on flood
mitigation infrastructure, SWM and
urban improvements
• Already approved by WB
• WB estimated that investments
deliver 91m cedi in flood reduction
benefits annually, increasing over
time
Two Retention ponds
• Expected to leverage substantial
planned investments by WB
• Annual benefits of flooding
increase by 20%
• 18m cedis per year rising with GDP
per capita growth
• These benefits are ‘expected value’
and account for rare but very costly
flooding events

9. Retention Ponds would accrue a total benefit of
GHS 285m, BCR = 1.3
Intervention Benefits
(millions
cedi)
Costs
(millions
cedi)
BCR
Retention Ponds 285 222 1.3
• There are 2.5 million people living in the Odaw River Basin with 161,000 people
at risk of flooding
• Retention ponds are a low-cost way to mitigate some flooding
• The investments would leverage large existing investments under GARID

10. Intervention 2
Storm Drain Widening

11. Storm drain would cost 124m cedi initially, then
6m every year in maintenance
Costs
• Upfront cost = 124m cedi
• Dredging cost = 13.39m cedi for 13.55km
• Concreting Cost, including steel = 110.64m
for 11.25km
• Ongoing costs 100m cedi until 2050 (95%
of this cost covers maintenance &
communication).
Current area near proposed storm
drain, Taifa Obohene

12. Intervention would lead to 12% reduction in possible
flood damages & 30% reduction in diarrheal disease
Benefits = 379m cedis
Flood mitigation benefits = 18m cedi
per year
• 20% increase in flood benefits under
GARID equivalent to GHS 285m at 8%
discount rate
• Reduced diarrheal disease = 5.6m cedi
per year
• 30% reduction in diarrhea disease in
population catchment around drain
(500,000 people)
• One bacterial study suggested that
uncovered drains account for 60% of
all diarrheal disease in Accra
• 25,000 cases of diarrhea avoided
• 10 lives saved per year, 6 of them
children
• All benefits rise over time with GDP
growth

13. BCR for Storm Drain
Intervention Benefits
(millions
cedi)
Costs
(millions
cedi)
BCR
Storm Drains 379 216 1.8

14. Intervention 3
Community based Solid Waste management

15. Intervention Description
• Entrust a private entity with full responsibility
within a given ‘camp’ – a defined area of roughly
50,000 people to:
• Provide frequent collection services via provided HH bins
• Clean streets of litter
• Address rodent and insect infestation
• Provide and remove skips
• Payment based on achieving defined goals and
cleanliness
• Requires involvement of people in community for
job creation and enforcement
• Improvement over status-quo passive SWM model
• Based on project done in Jamestown, Accra in 2014

16. The cost per camp is 6m cedis, with 1.2m in start
up costs
Population Description
• 50,000 people
• 3,125 compounds with 2 x 120L bins each
• Weekly collection
• Generates 100,000 L of waste per day
• 60% organic taken to compost plant
• 30% non-organic taken to skips and
emptied daily
• 20% recyclable taken by pickers to resell
Costs = 6m over 5 years
Start up costs = 1.2m
• 6250 bins @ 180 cedis each
• 3 large skips @ 3500 cedis each
• 9 tricycles (for pickers) @ 1800 cedis each
Ongoing costs = 4.8m over 5 years
• 985,000 cedi per year for daily skip emptying
• 900 cedi per skip per day
• 180,000 cedi per year for rubbish collection,
cleaning, de-silting and other tasks
• 5 years of operations before skips, bins and
tricycles need to be replaced

17. Intervention would lead to 6.4m cedi in benefits
Benefits = 6.4m cedi over 5 years
Willingness-to-pay for SWM services
• Theoretically encompasses all benefits of
SWM including health
• A study in Ghana noted a lower bound WTP
of 2 cedi per HH per day
• A benefit equivalent to GHS 1.5m per year
for a given camp of 12,500 households /
3,125 compounds.
• Over a 5-year period, the present value of
benefits is GHS 6.4m using an 8% discount
rate.
Speculative additional health benefits
• If one believes WTP does NOT include health
benefits
• 10% reduction in malaria and enteric
infections due to cleaner environment
• 5 deaths avoided per year
• 6,800 cases of enteric infection avoided
• 980 cases of malaria avoided
• 15m cedi over 5 years

18. BCR for Community based Solid Waste
Management
Intervention Benefits
(millions
cedi)
Costs
(millions
cedi)
BCR
Community SWM 6.4m 6.1m 1.1

19. Summary BCR for Urbanization Interventions
Intervention Benefits
(millions
cedi)
Costs
(millions
cedi)
BCR
Retention Ponds 285 222 1.3
Storm Drains 379 216 1.8
Community SWM
(figures for one
community)
6.4m 6.1m 1.1