Why do seasonal prairie pothole marshes often dry up during summer?

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Bald cypress trees with wide, flared trunks stand in still, shallow water in a Louisiana swamp, their green foliage creating a dense canopy. — Wetland Stately bald cypresses (*Taxodium distichum*) thriving in a Louisiana swamp.

Seasonal prairie pothole marshes often dry up during the summer because they are formed in low-lying depressions created by uneven glacial scouring, which primarily fill with precipitation and melted snow.1

Because these wetlands rely on these surface water sources rather than consistent groundwater or river flow, their water levels are highly sensitive to climate patterns and seasonal changes. As temperatures rise and precipitation patterns shift during the summer months, the water in these shallow depressions evaporates, causing the marshes to dry up.1