Niger River Basin Evaporation for January 1985 - 1999

Throughout the year there is a clear north south divide in evaporation over the Niger basin. Only for July-August is actual evaporation estimated for the northern reaches, this links to rainfall and runoff levels peaking in the basin during these months. It is during these months that the inner delta (a vast inland floodplain) is at its greatest and evaporation losses from this are substantial. The period February to March has the lowest estimates for evaporation primarily because the soil moisture deficit is greatest and little rainfall has occurred in the preceding months. The lack of water during the dry period means actual evaporation does not occur despite the high temperature. Only in the lower delta reaches are there evaporation estimates for all months.

Evaporation Legend (mm/month)

Bargraph referencing the colours on the evaporation maps.

Other Niger Maps

Niger Evaporation Maps