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Clean Water Act: Chesapeake Bay Watershed Under Threat

The current administration’s proposed changes to the Clean Water Act could drastically remove protections that help keep our water clean, putting important ecosystems at risk.

Published March 22, 2019

The Chesapeake Bay is the largest estuary in the United States with more than 18 million people and 2,700 species calling its watershed home. Throughout its 64,000 square miles, interconnected rivers, streams, wetlands and tributaries feed into the Bay.

Vernal pool

If proposed changes to the Clean Water Act were to pass, some of these interconnected sources of life in the Chesapeake Bay watershed—vernal pools and ephemeral streams—could be at risk of ruin.

Vernal pools are still bodies of water in forests that fill up during the wet seasons, then dry up entirely during dry spells in late summer. That’s why they could be at risk—proposed changes to the Clean Water Act would remove protections of waters that don’t exist year-round, even if they serve as keystone habitats for hundreds of species. Biologists have documented over 700 species that use vernal pool habitats in the northeastern region of the United States.

Bull frog in a stream

Many species of forest-dwelling frogs, toads and salamanders make annual migrations to vernal pools for breeding, egg laying and aquatic larval development. Their survival depends on the continued existence of vernal pools throughout their range.

These temporary pools are especially important to woodland amphibians because they lack the presence of fish, which are a major predator of their aquatic larvae. Because vernal pools are dry by summer’s end, they’re not inhabited by fish that can be voracious predators of tadpoles and salamander larvae.

The lack of protection for vernal pools would create the opportunity for development, leading to loss of vernal pool habitat that’s critical to species diversity and the greater forest ecosystem.

Another seasonal body of water at risk under these changes is what experts call ephemeral streams, which flow seasonally or after rain events. During dry spells, they change from a continuously flowing stream to a series of pools connected by below-surface flow, or they dry up completely. Similar to vernal pools, they are important habitat to many species, including species of streamside salamanders that avoid fish predators by using these temporary streams for egg laying and aquatic larval development.

Both vernal pools and ephemeral streams also play a role in filtering the water we drink and the water that runs into the Chesapeake Bay, which we’ll explore next week—so stay tuned!

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