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Over the past 15 years, we have worked on numerous projects across Arkansas and come to know her ecology incredibly well. Each site we’ve tackled presented unique challenges, yet upon completion, each contributed in its own distinctive manner to the restoration of the surrounding environment. Throughout our time getting to know the needs of each of Arkansas’ unique ecoregions, one ecological phenomenon holds a special place in our hearts: Wetlands! Not only do wetlands provide a unique aesthetic to any given park or project site, but they are also an incredibly effective and not to mention a natural way to mitigate stormwater runoff.
According to the EPA, Wetlands are areas where water covers the soil or is present at or near the surface of the soil all year or for varying periods during the year, including during the growing season. This prolonged presence of water creates conditions that favor the growth of specially adapted plants and promote the development of characteristic wetland soils.
Wetlands are found on every continent and in every condition except Antarctica. Their conditions vary due to regional and local differences in soils, climate, hydrology, vegetation, and human disturbance. However, the EPA recognizes two categories: coastal or tidal wetlands and inland or non-tidal wetlands.
As the name suggests, these wetlands are found along the coast and are closely associated with partially enclosed coastal bodies of water where freshwater from rivers and streams mix with salt water from the ocean.
The water in these coastal areas typically has high salt levels and constantly fluctuates due to tidal action, making it unsuitable for most plants. As a result, many of these shallow coastal areas are mostly mud flats or sand flats with little to no vegetation.
This is not to say that no plants have successfully adapted to this environment. Several grass genera have adapted along the Atlantic, Gulf, and Pacific coasts. At the same time, in more tropical climates, like southern Florida and Puerto Rico, you can find tree and shrub genera that thrive in saline conditions.
Non-tidal wetlands are commonly found in floodplains along rivers, streams, or the margins of a lake or pond. These wetlands include marshes, wet meadows, swamps, and other similar environments.
(If you want a complete list, see the EPA’s Wetland Classifications and Types list!)
Several non-tidal wetlands are seasonal, meaning they are dry one or more seasons out of the year. Herbaceous plants dominate these areas, and frequently, they occur in poorly drained depressions, floodplains, and shallow water areas along the edges of lakes and rivers. Major United States regions that are favorable to inland marshes include the Great Lakes coastal marshes, the prairie pothole region, and the Florida Everglades.
Non-tidal wetlands would be what we see in Arkansas. According to a study presented to Congress in 1990, it is estimated that Arkansas originally had 9.8 million acres of wetlands, representing almost 30% of the state's total surface area. However, by the mid-1980s, that number had dropped to 2.8 million acres or a 72% loss (Dahl 1990).
Arkansas' Delta region, which contained around 8 of the original 9.8 million acres of wetlands, suffered the most tremendous losses. Approximately 875,000 acres remain, an 89% loss, greater than in any other Delta state (Dahl 1990).
The decrease in wetland acreage is mainly due to the land used for agriculture and urban expansion. Of course, agriculture was and continues to be one of the pillars of our economy. According to the USDA’s National Agricultural Statistics Service, as of 2022, Arkansas was in the top 10 states in producing several essential crops. While we depend on this business to sustain our economy, it’s important to us that we note that EDG believes the future of Arkansas Agriculture is the introduction of Regenerative Agriculture–but that’s another article for another day!
The question remains: if they occur in poorly drained areas and floodplains, isn’t that a problem? Our cities are not designed to be covered in water all year or even for various periods during the year. What makes them an essential part of our ecosystem?
YES! Wetlands are among the most productive ecosystems in the world, comparable to rainforests and coral reefs. This is due to the biodiversity found in these habitats.
One of the easiest ways to conceptualize a wetland's immense variety of organisms is to think of it almost like a “biological supermarket.” Because of its biodiversity, it attracts several different animal species who act as customers at the supermarket. Dead plant material breaks down in the water to form small particles of organic material, which small insects, fish, reptiles, and many other animals eat.
Not only do wetlands increase the biodiversity of the local environment, but they also protect the surrounding area from potential flooding by reducing the frequency and intensity of floods, acting as natural buffers, and storing a significant amount of floodwater. According to the EPA, a wetland typically stores approximately one million gallons of water per acre of wetland.
Moreover, “wetlands store carbon within their plant communities and soil instead of releasing it to the atmosphere as carbon dioxide. Thus, wetlands help to moderate global climate conditions.”
As Dahl noted in the study referenced above, Arkansas' number of naturally occurring wetlands is decreasing significantly. If we are to continue to see the benefits of these ecological wonders, we need to take action. This is where wetland restoration and construction come into the discussion.
In short, wetland restoration manipulates a former or degraded wetland’s physical, chemical, or biological characteristics to return to its natural functions. These practices can include re-establishing a former wetland or repairing a degraded one.
Voluntarily restoring wetlands has recently grown as an area of interest across the federal family, with several agencies now being incorporated into preserving these assets. Various agencies are responsible for lobbying legislation stipulating the protection of these areas and other wildlife.
While preserving existing wetlands should be a priority, it does nothing to account for the acres of wetlands lost to urban sprawl over the years. This is why scientists, engineers, and landscape architects are constructing systems replicating a natural wetland's functions.
These constructed wetlands use natural processes such as select vegetation and soils to improve local water quality. While it might seem like extra effort, they are often less expensive to build than more traditional stormwater treatment options and have low operating and maintenance costs.
The restoration and construction of wetlands is a stormwater treatment method that EDG has championed in Arkansas over the past several years—one of our most notable wetland projects is Osage Park in Bentonville. Osage Park’s 12-acre wetland system, designed by Principal and Co-Founder Martin Smith, is a piece of green infrastructure that soaks up and filters stormwater, as previously mentioned, before slowly releasing it, decreasing flooding downstream and improving the water quality. This is an example of where we utilized an existing wetland that was already performing this process; all we did was expand it and create a connection to Lake Bentonville to magnify these already naturally occurring benefits.
William E. Clark Wetlands in Little Rock is a similar project whose main goal was to restore a natural sandbar habitat on the Arkansas River's banks that collects and filters runoff from a large watershed in east Little Rock. Our team worked closely with city officials, the public, nonprofit organizations, and specialists from various fields of expertise in river sandbar habitat restoration. The design included opening a manmade revetment that allowed the river to flow into a 6' deep aquatic passageway into the sandbar. This channel creates a prime aquatic spawning habitat for various indigenous species of the Arkansas River.
Not only have these wetlands improved the surrounding ecosystems, but they also add to the aesthetics of community space and give visitors the chance to engage with an ecological phenomenon that is otherwise unknown.
Collective action is needed, whether through voluntary restoration initiatives or the construction of artificial wetlands. As stewards of our environment, we must recognize the profound importance of wetlands, advocate for their preservation, and actively participate in endeavors that ensure a sustainable and vibrant future for these unique ecosystems.
