The watershed of the Sangha ( 213 400 km2) is a sub-basin of the Congo River basin, extending in Cameroon, Central African Republic and Republic of Congo in Central African forest medium. These rural people are dependent on natural resources. Their income-generating activities are carried according to the rainfall rate. However, during these last decades, the basin has known robust rainfall variability wich destabilizes the ways of life of the populations. Thus, this work seeks to contribute to the study of pluviometric hydro variability in this area while highlighting the impacts and farmers'' reactions to its consequences, and identify the limitations of these reactions by providing avenues for adaptation sustainable hydro rainfall variability. The socio-economic surveys will understand the impact of this phenomenon and the perception and reactions of local communities. To highlight the spatial and temporal variability in rainfall and flow, no time to daily, monthly and yearly on the area, the beginning and end of rain will be determined, the parameters of variability, the variables focused reduced the low-pass filter Hanning of order 2, the row breaks and water balance will be calculated.