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Poking Around the Pocomoke

Written on: July 13th, 2022 in Wetland Assessments

By Brittney Flatten, DNREC’s Watershed Assessment and Management Section

This summer, the Wetland Monitoring and Assessment Program (WMAP) team is doing wetland condition assessments in the Pocomoke River watershed. During an assessment, scientists look at soil quality, rate sources of water, evaluate the plant community, and identify stressors in or around the wetland. These observations help determine if the wetland is healthy and functioning. This work is part of WMAP’s ongoing project to assess wetlands in every watershed in Delaware and the Pocomoke is last on the list! Because the Pocomoke watershed is a small and relatively remote part of our state, it doesn’t always get the attention it deserves. Let’s take a moment to learn about some unique natural features in this part of Delaware.

Plant Communities in the Pocomoke

The Pocomoke watershed is home to the Great Cypress Swamp. According to Delaware Wild Lands, it is the largest freshwater wetland and contiguous block of forest in Delaware. At its largest, it was probably 60,000 acres, but much of that has been lost due to timbering and drainage for agriculture. A few years ago, our blog featured a post from Delaware Wild Lands about wetland and habitat restoration in Great Cypress Swamp.

As you might’ve guessed from the previous fact, some swamps in the Pocomoke watershed have bald cypress trees. Bald cypresses tolerate being partly submerged in water so they can live in very wet conditions. You can spot cypress trees in wetlands by their knees- woody structures that grow aboveground. Scientists haven’t reached a consensus on the purpose of knees, but one hypothesis is that knees help provide extra stability in soft, wet soils. For even more support, bald cypress trees have buttressed roots which flare out at the bottom of the tree compared to typical straight trunks. Bald cypresses are also deciduous conifers, so they drop their needles every year unlike evergreen conifers which keep their needles year round. The Great Cypress Swamp and Trap Pond State Park in the neighboring Nanticoke watershed are thought to have some of the northernmost natural bald cypress stands in the United States. These unique ecosystems are much more common further south in the Carolinas and Louisiana, but you can find them right here in the first state!

You may come across Atlantic white cedar swamps in this part of Delaware too. These swamps typically have a mix of Atlantic white cedar, gum, and maple trees. They are important habitat for sphagnum moss and even rare insect-eating carnivorous plants!

Want to explore other plant communities in Delaware? Check out University of Delaware’s Statewide Vegetation Community Map.

The Deep and Dark Pocomoke River

The mainstem of the Pocomoke River is known for its dark and sometimes mysterious appearance. The small headwater tributaries are in the Great Cypress Swamp, but further downstream before draining into the Chesapeake Bay, the Pocomoke can reach depths of 45 feet, which is rare for a river that is less than 100 feet wide. Most of Delaware and Maryland’s eastern shore are in the coastal plain ecoregion, where land is flat and near sea level, so rivers have a low slope and move slowly. When combined with the presence of large, forested wetlands, conditions can create blackwater streams. The leaf litter from cypress and cedar wetlands decomposes very slowly in low-oxygen waters and releases tannic acid into nearby streams, which gives the water its dark, yet clear appearance. Blackwater streams will naturally have lower dissolved oxygen and are more acidic, but there are still plenty of fish, reptiles, and amphibians that like to hang out in these ecosystems.

Preserving the Pocomoke

DNREC scientists in the Divisions of Watershed Stewardship, Fish and Wildlife, and Parks and Recreation all work to preserve unique natural areas in Delaware, through assessing wetland condition, documenting plant and wildlife communities, and protecting land with conservation areas, easements, and more. Non-profit organizations like Delaware Wild Lands and The Nature Conservancy work to preserve and restore cypress and cedar forests in Delaware and Maryland’s lower eastern shore. You can get involved too by learning more about protecting Delaware’s wetlands and watersheds. If you want to see these cool ecosystems in action, visit Trap Pond State Park or Pocomoke River State Park in Maryland. You can also learn more on the Delaware Wild Lands page for Great Cypress Swamp.

Results from previous assessment years and watersheds can be found in our library.

Tags: assessment, freshwater wetlands, Tidal Wetlands, Wetlands