To save Lake Chad, you must harvest the Typha that clogs it. You must dredge the soil build up that Typha has created, to restore proper stream and lake beds. When the weeds are gone, the water that arrives will evaporate more slowly, and build up, until it can replenish the aquifers and reestablish "lake effect" rains. We CAN change the climate back here. The tributaries need clearing too.

All of that Typha is biomass. The charcoal you need can be readily made from Typha, as well as ethanol to export or use. And the soil that you need to dredge can be used to rehabilitate desertified soil.