地理漫步·世界地理英语30篇（3）
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Lake Chad Basin: Hydrological Fragility in a Shifting Climate Zone
乍得湖流域：气候过渡带中的水文脆弱性
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Lake Chad, straddling Chad, Cameroon, Niger, and Nigeria, occupies a Sahelian transition zone between savanna and desert.
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Its surface area has shrunk by over 90% since the 1960s due to reduced rainfall and increased irrigation withdrawals.
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Unlike tectonic or volcanic lakes, Chad is a shallow, endorheic basin fed mainly by the Chari River’s seasonal floods.
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Evaporation exceeds inflow during prolonged droughts, exposing vast mudflats that alter regional albedo and dust emission.
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Transboundary water management remains weak despite shared dependence on this shrinking hydrological node.
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Aquifer recharge depends critically on floodplain infiltration during high-flow years—a process increasingly disrupted.
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Vegetation belts migrate southward as groundwater tables drop, intensifying pastoralist-farmer land-use conflicts.
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Satellite data show seasonal lake expansion now occurs later and contracts earlier each year on average.
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Sediment cores from basin margins record centuries of wet-dry oscillations linked to Atlantic sea-surface temperature shifts.
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Restoration efforts focus on re-establishing natural flood pulses rather than static water-level targets.