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Watershed Academy~Job Pathways for Water and Climate Resilience

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Restoring streams

February 14, 2023

Figure 1: On the left side is an unhealthy stream. On the right side is a healthy stream.

How is a Stream Restored?

Stream health is vital to a diverse and healthy environment. But, due to human influence, many streams have become unhealthy, leading to the loss of habitat and wildlife. For this lesson, you will learn signs of a healthy stream and ways to restore a stream.

Ways to restore a stream

When we restore nature, we want to work with nature. We are not opposing nature to fix it, we look at the natural process and try to emulate it. There are two main ways we restore streams.

  1. Piling up natural materials, like rocks, logs, and native plants along the edges of the stream
    1. Rock structures help slow down storm water flow (thus preventing erosion).
    2. How this is constructed is dependent on the type of erosion.
    3. This link includes different methods or stream banks constructions that help slow down erosion: 
  2. Restoring natural plant life
    1. Includes planting a diversity of native plants near the stream.
    2. Variety of structural plants (tall, medium, small)
    3. Planting these native plants help restore the stream by bringing structural plant diversity, a canopy, plant diversity, and a vegetation buffer.
  3. Induced Meandering
    1. You may have noticed that rivers aren’t straight, they usually curve and bend around. (insert graphic. Check out this video to find out why that happens.
    2. We want to replicate this movement is rivers because a river that curves is a lot healthier than a river that just flows straight. This is because the curves of the river help retain sediment, lessens erosion, and offer habitats for plants and wildlife.

Figure 2. Meandering river on left side and a straight river on the right. Notice the differences in health?

 

Signs of a Healthy Stream

  1. Structural Vegetation Diversity: More than three height classes in vegetation. This means that there is tall vegetation (like trees), medium vegetation (like shrubs), and short vegetation (like grass) surrounding the stream.
  2. Lower Bank Stability: The streams bank is stable and experiencing little to no erosion.
  3. Plant Diversity: A variety of plants is a sign of a healthy stream.
  4. Canopy shading the water: This helps cover the stream, making the stream have a cooler temperature. Cooler water means more oxygen, thus more life can inhabit the water.
  5. Water Quality: checking the turbidity, pH, and nutrients (Nitrogen and Phosphorous) helps determine stream health.
  6. Pools and Riffles: Pools are deeper sections of the stream  that provide still water while riffles are shallow parts will turbulent water. A stream needs a good mix of both as pools provide aquatic life shelter. Riffles are also important as it makes the water move fast, thus providing more oxygen to aquatic life.
  7. Vegetation Buffer:  Vegetation buffer is an area of dense vegetation that helps traps sediment and slow runoff . This is important as it prevents erosion in the stream .

An unhealthy stream would not meet the qualifications above! Rather, it would be the opposite. Fore example, a stream with a lot of erosion is unhealthy. Keeping in mind what a sign of a healthy stream is, we can develop ways to restore streams to that state of health!

In this lesson we learn that we can restore a stream! We do this by understanding what a healthy stream looks like and try to emulate it. A healthy stream has structural vegetation  diversity, lower bank stability, plant diversity, a (plant) canopy, good water quality, and a vegetation buffer!

Next up is a quiz! Can you recall what you just read?