Bani River - Talo Dam

Talo Dam

In 2006 the Talo Dam was constructed to irrigate parts of the floodplain to the south of the river near the town of San. Prior to the construction of the dam, these areas were only fully flooded in very wet years, the most recent of which occurred in 1967. The dam is located 43 km west of San, 66 km downstream of Douna and 110 km upstream of Djenné. The dam acts as a weir in that water can flow over the top of the retaining wall. The construction of the dam was highly controversial. The environmental impact assessment commissioned by the African Development Bank was criticised for not fully taking into account the hydrological impact downstream of the dam.

The retaining wall is 5 m high and 295 m in length, creating a reservoir with a capacity to retain 0.18 km3 of water. This volume represents 1.3% of the average annual discharge of the river (over the period 1952-2002 the average discharge was 13.4 km3). A downstream flow of 10 m3/s can be maintained during the dry season by opening a sluice gate. From the published information it is unclear how much of the total discharge will be diverted for irrigation and, of the diverted water, how much will drain back into the river. The downstream effect of the dam will be to delay the arrival of the annual flood and to reduce its intensity.