摘要：Over the last 40 years, Lake Chad, once the sixth largest lake in the world, has decreased
by more than 90% in area. In this study, we use a hydrological model coupled with a
lake/wetland algorithm to simulate the effects of lake bathymetry, human water use, and
decadal climate variability on the lake's level, surface area, and water storage. In addition
to the effects of persistent droughts and increasing irrigation withdrawals on the shrinking,
we find that the lake's unique bathymetry—which allows its division into two smaller
lakes—has made it more vulnerable to water loss. Unfortunately the lake's split is favored
by the 1952–2006 climatology. Failure of the lake to remerge with renewed rainfall in the
1990s following the drought years of the 1970s and 1980s is a consequence of irrigation
withdrawals. Under current climate and water use, a full recovery of the lake is unlikely
without an inter-basin water transfer. Breaching the barrier separating the north and
south lakes would reduce the amount of supplemental water needed for recovery.
