Figure 6. Average drought severity between 1970 and 2010 for both south-eastern (S-E) and north-western (N-W) areas

From

Spatio-temporal Drought Characterization for the Upper Tana River Basin, Kenya Using Standardized Precipitation Index (SPI)

Raphael M. Wambua, Benedict M. Mutua, James M. Raude

World Journal of Environmental Engineering. 2015, 3(4), 111-120 doi:10.12691/wjee-3-4-2