Habitats throughout the watershed play a large role in determining the health of the Chesapeake Bay and the quality of our drinking water.
Vernal pools and ephemeral streams are bodies of water that are seasonal and may dry up completely or stop flowing during dry summer months or periods of drought. However, their temporary nature does not diminish their importance to our drinking water’s quality and health of the Chesapeake Bay.
Vernal pools, scattered throughout the Chesapeake Bay watershed, act as reservoirs that capture, store and filter polluted runoff from stormwater before it enters streams and rivers—which are often the source of our drinking water—and the Bay.
Water held in vernal pools gets filtered as it slowly infiltrates the soil. This subsurface flow often discharges from hillside springs, supplying cool, clean water into freshwater streams. This process keeps these streams flowing more evenly throughout the year. These “natural reservoirs” get topped off after every rain event, repeating the slow discharge of clean filtered stormwater runoff over and over.
Similar to vernal pools, ephemeral streams can also capture, store and filter out sediment from polluted runoff before it enters larger, permanent streams, rivers and tributaries, which are often the source of our drinking water.
A major issue facing the Bay is polluted stormwater runoff—rainwater entering the Bay that rushes over pavement instead of sinking into soil and getting filtered after a rain event. Toxins and pollutants that run into the Bay from the pavement can have a detrimental effect on the Bay’s inhabitants. Vernal pools and isolated freshwater wetlands function as filters for water headed to the Bay.
While these habitats help filter and protect the drinking water of 75 percent of the watershed’s residents, they also keep the Bay’s interconnected landscape and waterways intact and keep ecological systems functioning.
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