Droughts lead to significant environmental and economic consequences, especially in arid and semi-arid areas like the Sahel. While site-level assessments of drought in the Sahel are abundant, assessments at the scale of entire hydrological basins are less common. Here, we use a new drought index called the terrestrial water storage index (TWSI) to assess trends in drought throughout the Senegal River Basin. This area covers parts of Guinea, Mali, Senegal, and Mauritania, the study period is between 2003 and 2020. Over the entire period, water storage in the Senegal River Basin is increasing by 0.87 km3 y -1 on the total area of the basin. However, we observed two distinct phases within the time period: an overall water deficit between 2003 and 2012 and a surplus between 2013 and 2020. We also found variations in terrestrial water storage from highly negative at the end of the dry season (-12.47 cm in May 2003) to strongly positive at the end of the rainy season (15.30 cm in September 2020). Our study suggests that the TWSI can be a useful index for regional hydrological drought monitoring, especially for areas where meteo-hydrological observations are insufficient.

Water is an important resource for evolution and development of the economy of the North Development Region of the Republic of Moldova. From its availability and facilities to supply depend over 909 thousands inhabitants or 25% of the country population. The most important water resources are surface water that are represented mainly by the Dniester and the Prut rivers situated at the borders of the pilot region as well as groundwater. Internal rivers are characterized by low flow and do not represent significant resources. Surface water resources lead to decrease for the last decades due to different factors including reservoirs impact as well as climate change. Development of water supply and especially water sewerage system is an important factor in order to assure people and industries with water and qualitative life. In this regard, plus to evaluation of water resources dynamics, the aim of the present research is to identify the regional and local assessment of the state and use of public water supply and sanitation systems in the mentioned region for the last decade (2010-2020). Thus, total volume of abstracted water for public water supply systems was, on average, 18.8 mil. m3. For the study period, the total volume of water delivered to the population increased by 1.8 times (4.1 mil. m3), including in rural areas by 4.5 times (by 2.6 mil. m3), and in urban areas, by only 35 % (1.6 mil. m3). As a result of the expansion of the aqueduct network, ˜½ (48%) of the population of region has access to public water supply systems, including 83% in urban areas and only 31% in rural areas. Despite the rapid expansion of public aqueducts, water consumption per capita is low and is only 71 l/day, including 84 l/ day in urban areas and only 53 l/day in rural areas. Population access to the public sewerage systems is only 19%, including 55% in the urban areas and only 0.3% - in the rural areas. Slow expansion of the public sewerage systems is caused by higher costs compared to water supply systems, and most local public authorities do not consider them as a priority