How Does Erosion Affect Water Quality?

How Does Erosion Affect Water Quality

Erosion, or the wearing away of earthen material, results in faster moving surface water.

Instead of soaking into the soil, rainfall, commercial wastewater, and municipal wastewater quickly run downhill into large water bodies.

Any pollutants in the wastewater and storm water are carried along with it in high concentrations.

Erosion speeds up water contamination.

Plants Act As Filters

Erosion is more likely to happen in areas with little to no vegetation. Grasses, trees, and shrubs hold soil together with their root systems.

This, in turn, absorbs surface water rather than allowing it slide directly into lakes and streams.

It has the effect of spreading out any pollutants. This lowers the concentration of those pollutants in the water supply.

Slow It Down

Water flows faster depending on a few things:

  • Steeper slopes
  • Fewer plants and barriers
  • Heavier rainfall
  • Dense soils

For example, a steep, hard-packed dirt hillside without much grass in a heavy rainfall area will see high rates of erosion.

In contrast, a hillside with sandier soils (allows water to penetrate) and some grass, trees, and shrubs will deal with the heavy rainfall much better.

Spread It Out

The goal of any filter is to reduce the concentrations of unwanted substances.

Whether this is your home water filter or a grassy hillside, the overall idea is the same.

We want to spread out contaminants to make them more manageable.


Concentrated contaminants like the herbicides Alachlor and Atrazine can have life-altering effects.

Atrazine can harm developing fetuses in the womb.

Alachlor can damage the liver, kidneys, spleen, the lining of the nose, and eyelids. It can also cause cancer.

  • Note: Alachlor was specifically designed for controlling (killing) grasses and weeds. This is done so crops can grow, but it destroys the integrity of the soil over time. It also poisons people.

Overworked Soils

In overworked soils, these contaminants can build up. The soil becomes denser and as rain falls they follow the paths of least resistance.

These paths are often erosion channels leading to low ground. Low ground is where water accumulates into ponds, lakes, rivers, and streams.

These are the water sources we rely on in communities around the world.

Conclusion: How Does Erosion Affect Water Quality?

Fast-moving water carries pollutants into water supplies quickly over eroded soil.

Those concentrated pollutants are harder to filter, requiring more energy.

The solution to better water in erosion-prone areas involves:

  • More plants to hold on to the soil.
  • Healthy root systems to hold nutrients and filter harmful substances.
  • Water filters in homes and businesses.

Learn More About Water Quality

Interested in the water quality where you live?

We created an easy way to find water quality data for cities across the United States.

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