Protecting Watersheds: Riparian Conservation

Written By Coastal Prairie Conservancy

by Wanda Anglin

Image Courtesy of (Martin et al., 2012). More information can be found here.

The coastal prairie remnants protected by the Coastal Prairie Conservancy are part of a vast historic grassland. This ecoregion spans nearly 30,000 square miles along the Gulf of Mexico, stretching from west of the Mississippi Delta in Louisiana, through Texas, and down into Mexico, reaching the southern tip of the Laguna Madre estuary. Collectively known as the West Gulf Coastal Plain or Western Gulf Coastal Grasslands, this ecoregion goes by different names depending on the region: the “Cajun Prairie” in Louisiana, the “Coastal Prairie” in Texas, and the “Tamaulipeco Grassland” in Mexico.

Prior to European settlement, the Cajun Prairie is estimated to have spanned 2.5 million acres in southwest Louisiana, while the Texas Coastal Prairie encompassed approximately 6.5 million acres. Since the arrival of Spanish explorer and cartographer Alonso Álvarez de Pineda in Texas in 1519, the coastal prairie has undergone tremendous changes. Over 99.9% of the historic coastal prairie has been plowed for agriculture or bulldozed for the development of housing, buildings, and roads. Today, less than one-tenth of one percent (0.1%) of the native, undisturbed coastal prairie remains. It took just 500 years to wipe out millennia of prairie habitat.

The low, flat Coastal Prairie plain extends over 360 miles North to South and ranges from 50 to 100 miles in width. It serves as the transition zone between the landmass of North America and the ocean. Its position on the continent results in the prairie hosting thousands of miles of riparian environments, as watersheds carry melted snow and rain through the prairie toward the Gulf.

Of Texas’ 14 major rivers, all but three flow through the Coastal Prairie. Rivers, streams, and lakes are vital to the myriad of people, plants, and wildlife that call the coastal prairie home. It is not just the freshwater these bodies of water provide, but also sediments and nutrients that make life on the coastal prairie possible. Let’s take a look at how the riparian environments within the watersheds of 11 of Texas’ major rivers are affected, and what we can do to conserve what we have and restore what has been lost.

What’s a Riparian Zone?

Photo Courtesy of Ryan McGillicuddy.

The name for the relatively narrow band of land along river and stream banks is called the riparian zone, occasionally called a riparian corridor. It is a transition zone between the stream channel and the uplands. It has a different composition of plant species than the upland areas, and its health is crucial to the health of both the channel and the uplands, as well as for maintaining water quality and supporting fish and wildlife habitat.

Depending on the size of the river or stream, a riparian zone can range from 25 to over 200 feet in width. You can identify where the riparian zone ends and the uplands begins by observing the top of the slope where the vegetation changes. For example, in the riparian area, you will see plant species that prefer moist environments and can survive with extended wet feet, such as willows, rushes, and sedges. Depending on the region, at the top of the slope you will see typical upland vegetation. In the Coastal Prairie, you might encounter various types of tall prairie grasses, such as little bluestem and Indiangrass, along with a variety of forbs. In many upland areas near streams, you can also find trees like sugarberry, cedar elm, pecan, black willow, and honey mesquite.

Benefits of Healthy Riparian Environments

Riparian zones perform many ecological and structural functions in protecting streams, surrounding upland, downstream bodies of water, and wildlife habitat. Preventing degradation and restoring riparian environments to return them to working order provides many benefits such as: 

  • Provide beauty and opportunities to enjoy nature

  • Reduces changing landscapes that can affect property values and acreage use

  • Increases economic value through wildlife, livestock, timber, and recreational enterprises

  • Increases real estate value of property 

  • Protects diversity of aquatic and upland species

  • Connects habitats for a wide variety of wildlife including migratory species

  • Reduces flooding and flood intensity downstream

  • Reduces erosion that impacts everyone and everything in and downstream of bodies of water

  • Improves water quality as nutrients and contaminants are filtered in the floodplain and down into groundwater tables

  • Provides vegetation canopies to cool water, land, and wildlife as well as provide food for aquatic and riparian fauna

  • Reduces instances of invasions of undesirable exotic riparian species

Reducing Erosion

River Bank Erosion Photo Courtesy of Ryan McGillicuddy.

The preservation and restoration of native vegetation is one of the most critical ways to reduce erosion. When riverbanks are cleared of vegetation, they experience increased loss of soil, rock, and plant life, but the effects extend far beyond the immediate point of disturbance. Erosion can increase intensity of downstream flow which results in stream incision, down cutting, or gullying. This can lower the river deeper thus resulting in flooding less often. This may seem like a good idea, but in actuality, it means the nutrients and moisture do not spread out into the riparian area. There is less soaking in and filtering into the groundwater, which lowers the water table and affects areas beyond the riparian zone. 

Erosion also changes the size or quantity of deposits (rock, sand, silt) moving from upstream soil to downstream banks. While rivers and streams naturally change their meandering courses, they make changes over long periods of time, giving plants and animals time to adjust where they live. A sudden influx of heavy rock, sand, silt, or other sediments, can interrupt the efficient patterns of riffles, runs, and pools that the river has developed over time. A stream’s natural riffle-run-pool structure efficiently and effectively manages the water’s energy and controls how the river transports sediment. Disturbing that structure endangers the health of the riparian area and its inhabitants. 

Photo Courtesy of Ryan McGillicuddy.

For example, if a river bank is heavily eroded, all of the soil, sand, rock, roots, and plant material may get deposited over the downstream riffles. Riffles are the nurseries of rivers, where fish larvae and fingerlings thrive, along with vital species such as freshwater mussels. Without riffles, there are no future fish or mussels. Mussels clean river water very efficiently. In fact, they are called the livers of the river because of their ability to remove pollutants and nutrients.

It is not only vegetation on banks that prevent erosion. The roots and wood from fallen trees, and rocks of all sizes also help prevent erosion. People often remove these from their creek beds, but this is a mistake because they catch sediment, which helps build the natural environment slowly. They help dissipate energy, slowing water velocity and removing sediment from traveling downstream further. 

Allowing a river and its surrounding riparian environment to naturally evolve, or taking informed steps to restore any damage, supports water quality, wildlife habitat, and human well-being.

Moderate Flooding

Image Courtesy of Ryan McGillicuddy.

Those of us who live along the coast tend to think of floods negatively due to personal impacts on our communities. But if you consider the natural environment, flooding can be a beneficial part of the riparian zone. 

When water spills out of its normal channel, it extends into the riparian zone, and sometimes into the uplands during severe floods. The water is absorbed by the soil, trickling down into groundwater stores abd later being released back via gravity into the channel and lower areas of the riparian zone during dry conditions. In addition to this “battery” storage of water, the surrounding wetlands and frequently flooded areas close to the channel support species of fish and animals that are dependent on floodwaters. Also, some tree species, such as cypress and gum, need the flooding to thrive. Thus, a functioning floodplain provides many ecological benefits. 

Keeping these flood-prone riparian zones healthy and efficiently functioning benefits humans by naturally controlling and absorbing flood waters. When full of undisturbed native vegetation, riparian areas reduce the speed, force, height, and volume of flood waters as they move downstream. Clearing banks and using artificial methods of directing stream flows, such as using levees or straightening a creek to make it 'behave' as desired, are all human-made disasters that result in the loss of riparian zones and increased impacts from flooding.

Pollution

When most people think of pollution, they think of untreated industrial waste being piped directly into a body of water, or trash that is blown into urban sewer drains flowing into the water. While industrial polluters are an epidemic in the US responsible for a large quantity of damage to the quality of the riparian zone and the water within it, they are not the only major polluter to consider.

Agricultural land-use not only causes physical changes to riparian zones and the surrounding upland, but farmers also use chemical herbicides and pesticides to improve crop yields. When these substances seep into the groundwater or run off into a nearby stream, they harm animals, plants, and humans spreading the pollution downstream and ultimately into the oceans. 

Livestock farming, which includes cattle, pigs, goats, and sheep, is the biggest source of E.coli contamination of our streams and rivers. Even if the animals are not permitted to enter the body of water, rainwater carries the E.coli from their feces into nearby bodies of water as it traverses the watershed. All mammals carry E.coli, meaning sewage plants and septic tanks are major sources of E.coli contamination, which endangers us all. 

Loss of Habitat

Humans are the biggest endangerment to water quality and riparian areas as they siphon off unimaginable volumes of water for municipal, agricultural, and industrial uses. As population increases, development and the need for agriculture rise. Many areas around the country and world are seeing the effects. Often, we only talk about the effects on human life, but what about the wildlife? 

When you remove water from a stream, river, or lake, you are robbing wildlife of their habitat. Not just water-dwellers, but also those living in the riparian zone. Understanding the minimum or optimal freshwater inflows needed for wildlife living from the water’s edge to the uplands is challenging, making it even more difficult to appeal to or educate those who prioritize human needs.

But more and more people (especially readers of this blog) are beginning to understand when we endanger wildlife, we endanger ourselves. Upsetting the delicate balance of the food chain and the many systems that keep water clean and air breathable is detrimental to everything on our planet. 

Another way that habitat is lost is through invasive or highly aggressive plant species. The danger of plants, such as tropical species introduced in landscaping around homes and buildings, is that they can choke out native vegetation, turning the area into a monoculture, where one plant species dominates and eliminates diversity. Without plant diversity for food, shelter, and plant material for procreating and producing young, wildlife is diminished. 

One of the most prevalent invasives in Texas causing mono-culture environments along rivers (and elsewhere) is ligustrum, also known as waxleaf or large-leaf privet. A native of China, Japan, and Korea, this popular nursery plant and landscaper’s oft-preferred choice for hedges is a nuisance for the very reason that it is a favorite in yardscapes…it is resilient and fast-growing. One example I recently encountered in our Texas coastal prairie was in the Attwater’s Prairie Chicken Refuge . As a very experienced trail guide volunteer was sharing this amazing place, we decided to hike along the riparian zone. The San Bernard River and one of its tributaries, Coushatta Creek, run through the refuge. After seeing prairie diversity at its finest in the heat of the day, the cool shade of the riparian area was welcome. For a bit of the expedition, the same diversity was there among the towering trees and understory, but toward the south end of the refuge, the ground became bare and the color and intensity of the light filtering down to us changed. It was startling, making me pause to look around. I was in a ligustrum forest. There was nothing but ligustrum for a very long stretch of the walk. This in no way reflects on the Refuge, as removing ligustrum is costly, labor-intensive, and challenging. Since the monoculture consists entirely of ligustrum, removing it risks scouring the riverbank, causing erosion and potentially altering the river's structure, as previously discussed. Planting ligustrum is just one example of a human action that destroys wildlife habitat and will ultimately impact us.  

Though the challenges to our watersheds are increasing, there are organizations that make it possible for every citizen to educate themselves and participate in conservation and repair of our riparian zones.

Riparian Conservation in Action: WPPs

The goal of Watershed Protection Plans (WPPs) is to protect healthy water bodies from potential pollutant threats and to restore polluted water bodies. WPPs are community-driven and voluntary. Often initiated in areas that are beginning to see rapid development, these locally-driven projects bring diverse stakeholders together to address complex water quality problems across multiple jurisdictions. Stakeholders who craft and participate in implementing these plans come from many walks of life: landowners, ranchers, farmers, municipalities, businesses, residents (especially those with recreational interests), Chambers of Commerce, Soil and Water Conservation Districts, Groundwater Conservation Districts, state parks, oil and gas drillers, and more. 

The WPP approach to watershed management recognizes that solutions to water quality issues must be acceptable to the area’s stakeholders, economically feasible, and based on science-based environmental goals.

The planning process involves meetings and activities that integrate input from all watershed stakeholders to develop win-win solutions for the community, wildlife, and those benefiting from clean water and healthy riparian environments. Watershed protection planning is an effective tool to educate citizens about watersheds and water quality, aiming to motivate their participation in the WPP. During the planning process, stakeholders build relationships and open communication, leading to more effective resource coordination among local governments, state and federal agencies, and NGOs. WPPs promote a unified approach to seeking funding for implementation which can greatly accelerate the speed of implementation.  

Once a WPP is developed by the community’s representatives, it receives usually funding from the Environmental Protection Agency (EPA). 

WPPs are sponsored by one of 2 organizations: 

  • Texas State Soil and Water Conservation Board (TSSWCB)

  • Texas Commission on Environmental Quality (TCEQ)

There is little difference between the WPPs of these 2 sponsors, though TCEQ is most often in more urban areas. These organizations appoint a project manager, known as a watershed coordinator, to oversee the project, track grant spending, and monitor progress against the plan. A WPP’s day-to-day administration is facilitated by a watershed coordinator and its plans are maintained by the stakeholders. 

Learn more about WPPs and how one might save or restore water quality in your area:

How Can You Protect Watersheds?

The EPA offers tips on how small changes in your lifestyle can help keep your watershed clean and healthy:

  • Conserve water every day. 

    • Take shorter showers, fix leaks, and turn off the faucet when not in use.

    • Use native plants and trees that require little or no watering, fertilizers, or pesticides..

  • Take toxic household chemicals, antifreeze, oil, and pesticides to a recycling center or hazardous waste center rather than pouring them down the drain. 

  • Fertilize according to the product’s label…more is not better. Consider organic or slow release fertilizers.

  • Recycle yard waste in a compost pile and use a mulching mower.

  • Instead of concrete, use permeable surfaces like wood, brick, or gravel for decks, walkways, driveways, etc., which lets rain soak in rather than run off.

  • Pick up pet waste and dispose of it in the toilet or the trash.

  • Drive less; walk or bike. Many water pollutants come from car exhaust and fluid leaks.

To Learn more about riparian environments and conservation and how you can help:

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Bio: Wanda Anglin is a lifelong student and appreciator of the natural world and its interwoven systems. She is fortunate to live on a farm in a unique area of northeast Colorado County near Columbus, TX, where the coastal prairie meets the post oak savannah and Blackland prairie ecoregions as well as being home to the southeastern tail of the Lost Pines belt. All these ecotypes are seen on her small farm. As a Texas Master Naturalist, she participates in many citizen science projects that build on her understanding of how water, air, soil, flora and fauna, climate, and how humans choose to use Earth’s resources, are all inter-related. A change in one results in changes in the other systems. She jumps at every chance to share opportunities to help others understand how they can promote the natural world they want while enjoying Earth’s bounty responsibly.

Coastal Prairie Conservancy
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