We at the Illinois River Watershed Partnership love to get our hands in the soil for all kinds of watershed enhancement projects.  One of these projects is our annual Riparian Project tree planting event in Northwest Arkansas.  We talk about riparian zones a lot but what exactly is a riparian zone and why is it so important?  What makes for a healthy riparian zone?  Why do we plant trees for riparian zone improvement?  How can you help the IRWP enhance and preserve our riparian areas?

A typical riparian areaA typical riparian buffer zone

Photo Credit:  Manitoba Riparian Health


Riparian zones are the vegetated strips of land adjacent to streams where terrestrial plants transition to more water-loving plants at the water’s edge.  These areas help protect against soil erosion and stabilize the stream banks.  They provide water storage, runoff control, and water filtration that promotes water quality and protects against flooding.  Riparian zones provide habitats for a variety of plants, animals, fish, and aquatic insects.

Healthy riparian zones may vary some depending on location, geology, and climate but they all have several things in common:

  • Dense, diverse, native vegetation that is a mix of trees, shrubs, and water-loving grasses, rushes, and sedges.
  • Soil stays moist through most of the year.
  • Stream flow and level changes are usually gradual.
  • Water is usually clear, save for natural debris that helps create habitats for aquatic creatures.
  • A diverse array of plants, aquatic life, mammals, and birds.

A section of Oostanaula Creek, Tennessee before riparian restoration

A section of Oostanaula Creek, Tennessee before riparian restoration

Photo Credit: University of Tennessee Institute of Agriculture

By comparison, unhealthy riparian zones are usually sparsely vegetated without much variety in the types of vegetation, often consisting of upland vegetation and weeds.  Some impaired zones may even be bare soil that shows signs of erosion such as rills or gullies.  The soil may be hard and dry, directing more runoff to streams.  This can lead to muddy water and flash flooding that causes further erosion.  The water may have elevated concentrations of nutrients such as nitrates and phosphates or contaminants such as oil, grease, and gasoline.  The lack of shade can mean higher average and maximum water temperatures which means less oxygen in the water, limiting the types of fish and other aquatic life that can survive and promoting the growth of algae.  This affects the food chain and results in fewer mammals and birds living in the area.

A section of Oostanaula Creek, Tennessee after riparian restoration

A section of Oostanaula Creek, Tennessee after riparian restoration

Photo Credit: University of Tennessee Institute of Agriculture


So how do efforts like the IRWP’s Riparian Project help?  When riparian zones recover naturally, woody plants like trees and shrubs are the first to grow.  This is because they are more resistant to the forces of erosion.  As they take root, they help stabilize the stream banks so that plants like grasses, sedges, and rushes can grow and further hold the soil in place.  As the trees continue to grow, their canopy provides shade that can help regulate water temperatures.  The tree canopy also helps protect against the erosive effects of rain fall on bare soil.  When you plant trees in riparian zones, you are simply copying nature’s important first step to recovery!

An IRWP volunteer unloads a tree for planting

An IRWP volunteer unloads a tree for planting

So what can you do to help?

You can get involved by helping the IRWP plant trees on Saturday, September 13.  Click here to find a planting location near you.  You can also contact us  to volunteer or let us know if there are any locations in your area where you think restoration efforts such as tree plantings or removal of invasive species may help an impaired riparian area recover.

Spread the word.  Get involved.  We’d love to see you and your friends there!


Related Links:

IRWP Riparian Project

Register to Volunteer Saturday!


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