The document summarizes pre- and post-dam agricultural activities and irrigation development plans around the Akosombo and Kpong dams in Ghana. Before the dams, flood recession farming occurred on 51,800 hectares and dry season flows were insufficient for irrigation. After the dams, rainfed farming and small-scale irrigation increased, along with large-scale public and private irrigation projects totaling over 6,500 hectares. Planned irrigation development includes expansion of projects on the Kpong left bank, Kpong right bank, and Accra Plains totaling up to 150,000-200,000 hectares. Target values are identified for flood recession agriculture, irrigation water supply, and domestic water use in Accra and other areas

1. Re-optimization and
reoperation study of the
Akosombo and Kpong dams
Dr Marloes Mul

2. Pre-dam conditions
• 51,800 ha of flood
recession farming
• £160,000
• Dry season flows
insufficient for irrigation
• Fertile soils
• Timing unreliable
Post-dam conditions
• Rainfed farming
• Small scale irrigation
• Large scale public and
private irrigation
– Public – 5,500ha
– Private – 1,300 ha (and
2,000 within public
schemes)
AGRICULTURE COMPONENT

3. PRE- AND POST DAM AGRIC ACTIVITIES
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Before dam construction
Flood recession farming
Rainfed farming
After dam construction
Irrigation
Rainfed farming

4. PLANNED IRRIGATION DEVELOPMENT
• Irrigation (future)
– Kpong left bank – 3,800 ha
– Kpong right bank extension – 8,000ha
– Accra Plains Irrigation Project – upto 200,000 ha (but more
realistically 150,000ha
• Total water requirements (current 3,2 m3/s, future 105 m3/s)

5. • Flood recession agriculture
– Predictable flooded areas (larger the better, for
August and September)
• Irrigation
– Current 3,2 m3/s
– Future 105 m3/s
– Water level at intake (Kpong, Akosombo)
TARGET VALUES FOR AGRIC SECTOR

6. DAMAGES AGRIC SECTOR
• Costs
– Floods affecting irrigation infrastructure
– US$13,096 and US$ 19,828 per hectare
Flow in m3/s Q=3,000 Q=5,000 Q=7,000 Q=9,000 Q=10,000 Q=12,000 Q=14,150
Area Size (km2) 0 0 5 9 14 24 45
Future area (km2) 13 47 63 95 137

7. • Domestic water use
– Accra – 56 Mm3/a
– GWCL other 23 Mm3/a
– Other water users (industries, hotels) – 8.5 Mm3/a
• Infrastructural damages to be estimated per flood
– Hotels
– Houses
– Industries
TARGET VALUES FOR DOMESTIC

8. Thank you for your attention