Lake Chad the Yobe River in Nigeria/Niger. Despite high levels of evaporation, the lake is fresh water. Over half of the lake's area is taken up by its many small islands (including the Bogomerom archipelago), reedbeds and mud banks, and a belt of swampland across the middle divides the northern and southern halves. The shorelines are largely composed of marshes. Because Lake Chad is very shallow—only at its deepest—its area is particularly sensitive to small changes in average depth, and consequently it also shows seasonal fluctuations in size. Lake Chad has no apparent outlet, but its waters percolate into the Soro and
Chad–Nigeria relations the 1980s. Most religious violence was domestic in origin, but Nigerian police arrested a few Libyans, and Nigerian apprehension of Libyan infiltration through Chad intensified. Nigeria's 1983 economic austerity campaign also produced strains with neighboring states, including Chad. Nigeria expelled several hundred thousand foreign workers, mostly from its oil industry, which faced drastic cuts as a result of declining world oil prices. At least 30,000 of those expelled were Chadians. Despite these strains, however, Nigerians had assisted in the halting process of achieving stability in Chad, and both nations reaffirmed their intention to maintain close ties. In May 2014, in