Beneath their calm, waterlogged surface, wetlands act like giant sponges, soaking up stormwater, cleaning it as they go, and preventing floods that could overwhelm our communities.
Though sometimes seen as nuisance areas, wetlands are actually nature's quiet superheroes. They work in the background to clean our water, store carbon, and keep us safe from floods. They're also home to a variety of wildlife and plants that may struggle to survive in other environments.
According to the U.S. Environmental Protection Agency (EPA), wetlands are areas where the frequent and prolonged presence of water is at or near the soil surface. Swamps, marshes and bogs are well-recognized types of wetlands. However, some wetlands have drier or varying water systems like vernal pools, playas and prairie potholes.
The amount of water present in a wetland fluctuates as a result of rain patterns, dry seasons and longer droughts.
Storing excess water
Wetlands play a critical role in flood prevention by acting as natural buffers and sponges that absorb, store, and slowly release excess water. This reduces the speed and volume of water flowing into downstream areas, preventing or easing the impacts of flooding.
Wetlands have a remarkable ability to absorb large amounts of water, especially during heavy rainfall or storm surges.
Their spongy, porous soils, dense vegetation and irregular topography of wetlands allow them to soak up water, slow down the movement of water and hold it temporarily. The United States Geological Survey (USGS) explains that as water enters the wetland, it encounters plant roots, stems, and other obstructions, which reduce its velocity.
This excess water soaks into the ground to replenish groundwater supplies and spreads across a larger area before being released gradually, preventing sudden runoff and reducing the risk of downstream flooding.
Floodplain wetlands, which are adjacent to rivers and streams and sometimes called a "river bottom," provide space for excess water to spread out during floods.
When rivers overflow their banks, floodplain wetlands absorb and dissipate the water over a wide area, reducing the height and force of the floodwaters. This buffering effect helps protect homes, farmlands and infrastructure from damage.
Natures water filter
Wetlands filter water through a combination of physical, chemical, and biological processes that remove pollutants, sediments, and excess nutrients from the water. As the water enters the wetland, its movement slows around plants, which allows sediments to drop to the wetland floor.
According to Jeremy Nickolai, Brazos River Authority's field operations manager, "Wetlands are important in maintaining water quality."
“They are like filters that catch sediment and contaminants before they get into streams," Nickolai said. "They slow down the water, reducing erosion and giving biological processes time to break nutrients and pollutants."
As water passes through the wetland, pollutants are trapped in the soil and either broken down by chemical reactions or absorbed by plants and microorganisms. Some wetlands also neutralize acidic or basic pollutants through chemical reactions with soil components.
Wetland plants absorb nutrients like nitrogen and phosphorus, which are often present in runoff from agricultural fields, sewage, or urban areas. Plants use these nutrients for growth, effectively reducing their concentration in the water and preventing them from contaminating downstream water bodies.
According to Science Direct, the soils in wetlands are often rich in organic material and are home to diverse communities of bacteria and other microorganisms. These microbes play a key role in breaking down pollutants, particularly organic matter, into less harmful compounds. Wetland soils high in organic matter like peat, have the ability to filter out pollutants, such as heavy metals, pesticides, and other contaminants.
Science Direct states that wetlands, especially those with plants that grow partially submerged, contribute to oxygenating the water. Plants like reeds and cattails transport oxygen from the air into their roots, which promotes aerobic decomposition of organic matter by microorganisms. This process helps further break down pollutants in the water.
Wetlands in Texas
According to Texas Parks and Wildlife Department (TPWD), although Texas is perceived as a dry state, it contains millions of acres of wetlands of varying types. They play critical roles in its ecosystems, supporting biodiversity, flood control, and water quality. These wetlands include coastal marshes, freshwater swamps, riparian zones, and playa lakes.
Wetlands are essential for maintaining biodiversity, protecting water quality, controlling floods, and also supporting recreation and tourism. Many of these areas are protected as wildlife refuges or state parks.
"Wetlands are very unique habitats for wildlife also, birds, amphibians and sometimes fish," said Nickolai. "Oxbow lakes are a type of wetland that happens when a portion of a stream or river gets isolated by erosion. Theses oxbows become inundated during higher flow events. Alligator gar will use these oxbows as nursery habitat."
There are a few notable wetlands to visit within the Brazos River Basin.
The playa lakes found in the Upper Basin are shallow, seasonal wetlands that fill with water after rainfall. They are crucial for groundwater recharge and provide important habitat for migratory birds, particularly waterfowl.
Visit here to view an interactive map to the location of the playa lakes.
In the Central Basin, the Lake Waco Wetlands offer 3.5 miles of nature trails for hiking, bird watching and photography. This wetland includes a research and education center that are open to the public.
And in the Lower Basin, you can visit Brazos Bend State Park. This park is home to freshwater wetlands, swamps and lakes. The park contains a variety of wetland habitats supporting alligators, birds, and other wildlife. The wetlands here play a role in flood control for the Brazos River.
The park offers 37 miles of hiking trails, an observatory, wildlife viewing platforms for birdwatching along with bank fishing and a fishing pier.
Wetlands are more than just landscapes, they’re lifesavers, quietly defending us from floods while helping to clean our water.