Re-optimization and

reoperation study of the

Akosombo and Kpong dams

Dr Marloes Mul

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

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

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)

• 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

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

• 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

Thank you for your attention