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Dissolved Oxygen

In fast-moving streams, rushing water is aerated by bubbles as it churns over rocks and falls down hundreds of tiny waterfalls, saturating these streams with oxygen. In slow, stagnant waters, oxygen only enters the top layer of water, and deeper water is often low in dissolved oxygen concentration due to decomposition of organic matter by bacteria that live on or near the bottom of the reservoir. Dams slow water down, and therefore can decrease the dissolved oxygen concentration of water downstream.

Additionally, bacteria decompose organic wastes, including leaves, grass clippings, dead plants or animals, animal droppings, and sewage, removing dissolved oxygen from the water when they breathe. Bacteria also use oxygen to digest dead algae, which bloom when fertilizers run off into waterways. If more food (organic waste or algae) is available for the bacteria, more bacteria will grow and use oxygen, and the dissolved oxygen concentration will drop.

Removing trees can also affect dissolved oxygen concentrations in different ways. In general, as water temperature increases, dissolved oxygen drops. The bare soil exposed from removing the tree can erode, increasing the amount of dissolved and suspended solids in the water and decreasing dissolved oxygen concentrations.

Depleted dissolved oxygen in water will restrict or eliminate aquatic life. While some species of fish and aquatic insects can tolerate lower levels of oxygen for short periods, prolonged exposure will affect biological diversity and in extreme cases, cause massive fish kills.


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  • Adopt

    Are you a member of a group or organization in your community that would be interested in adopting this waterway? Contact us if you’re interested in learning more about stream adoption.

    Learn more about adopting a stream

  • Remove unused dams.

    If you have an antiquated or unneeded dam on your property, contact the Cumberland River Compact to discuss the feasibility of removing it. Walk the stream and inventory the location of any dams or obstructions, and let the Compact know so we can add these to our database or potential removal projects.

    Resources include:

    • Dam Inventory, Removal and Stream Restoration – Cumberland River Compact
    • How Dams Damage Rivers and How Dams are Removed – American Rivers
  • Limit Fertilizer

    Fertilizers, pesticides and other pollutants can attach themselves to soil particles and find their way to your creek.

    Resources include:

  • Allow for natural growth near waterways

    If you live or work next to a waterway, leave a 35′ to 100′ no mow zone on its banks. Allow natural and native plant growth in this buffer area or plant native trees, bushes, and groundcover. This vegetation can filter pollutants before they reach your waterway and provide other water quality benefits that far exceed those of a mowed lawn. Native plants and grasses require less watering and fertilizer and also provide important habitat for native species of wildlife.

    Resources include:

  • Plant a rain garden

    Rain gardens can filter and infiltrate stormwater that flows across your yard.

    Resources include:

  • Pick up after your pet.

    Pick up after your pet when s/he is on a walk, at the dog park, or in your own backyard. Dispose of this waste in the trash or toilet. Many pet stores and retailers sell biodegradable bags for picking up waste. Some companies offer pet waste removal services. You can also start a pet education campaign in your neighborhood and/or distribute biodegradable pet waste bags.

    Resources include:

  • Employ agricultural best management practices.

    Excluding farm animals from this waterway and providing them with alternative sources of water can prevent animals from trampling streamside vegetation and defecating in the waterway.

    Resources include:

  • Organize with others in your community. Make your voices heard and your votes count.

    Participate in community planning efforts and advocate for relevant measures that improve or protect water quality. Write to your elected official and let them know this is concern or invite them to speak about the impairment with your home-owners association. When elections come up, vote for candidates who will address the problem and hold them accountable to their promises. Support local watershed / environmental associations.

    Resources include:

  • Spread the word.

    Do your neighbors, family, or roommates know about the problem? Now that you know how to be an effective steward, enlist the help of others in your neighborhood. Share iCreek or resources within it with your neighbors and encourage them to join the effort to protect your creek.

  • Compost or recycle yard debris.

    Bacteria decompose organic wastes, including leaves, grass clippings, and other yard debris. These bacteria require dissolved oxygen from the water to breathe. When excess organic waste (or algae) is available to bacteria, excess bacteria grow, depleting dissolved oxygen levels required by other aquatic species.

    Resources include: