The FRIEND-Water program (FWP) is the oldest and the most transverse program within the UNESCO IHP. It allows large communities of hydrologists to collaborate across borders on common shared data and scientific topics, addressed through 8 large world regions. Research priorities evolve according to the projections given by the member States during the IHP councils. FWP further activities follow the IHP IX program with the support of the Montpellier UNESCO Category II Center ICIREWAD.

People from the Senegalese Peanut Basin deal with a dramatic increase of water scarcity due both to a rain deficit and a surface water salinization. We carried out the analysis of daily rain from 1950 to 2015 and water salinity of 78 wells on 300 km². We confirm a climatic break in 1970 leaded a long dry period until 2009, with a decreased of the rainy day number per year, probably driving a large extension of well salinization and salt soil crusting accelerated by a large tidal event in 1984.

The research of ruptures on rainfall and discharge long serial data from 1950 to 1995 on 3 close basins (of 2000 to 6000 km²) in Central African Republic has shown a high variability. The continental rupture of 1970 marking the drought on large West and Central African river basins is not clearly observed. However, all the studied basins have shown a degradation of their hydrological regimes since the end of the 1980s due to the drought severity.

This paper analyses the change of total suspended sediment (TSS) and total organic nitrogen (TON) loads of the Red River from 1960–2015 in which numerous dams in both China and Vietnam have been constructed. Strong decrease of TSS and TON loads allocated to the dam impoundments in spite of population and deforestation increase. The TSS flux decrease has driven a clear reduction of associated elements (nitrogen), which let to hypothesis a change in biogeochemical processes in the coastal zone.

Laos and Vietnam have switched from net forest loss to net forest expansion between 1990 and 2015. Based on long-term field measurements of land use, river flows, and weather data, we demonstrate that forest expansion can have extreme, yet opposite, impacts on water resources, depending on how the newly established tree-based cover is managed. The conversion of annual crops to teak plantations in Laos or to naturally regrowing forests in Vietnam led to increased and decreased flows, respectively.