Water Retention and Erosion Control

Retaining water -- rain or snow melt -- is the primary way to prevent erosion of soil. In some places, local ordinances require this. Even without the force of a law, it makes good sense to do so.

  • Topic: Watering
  • Author: Mary Ann Walz
  • Keywords: site preparation, watering, erosion control
  • Date: March 2006

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Retaining water—rain or snow melt—is the primary way to prevent erosion of soil. In some places, local ordinances require this. Even without the force of a law, it makes good sense to do so. Plants benefit from the moisture and need the nutrients found in good top soil to ensure healthy growth. Many places have such shallow top soil that losses of even fractional inches are inevitable.

So how can you retain the water in place?

One of the easiest ways to do this is through the use of a good cover of mulch on flower beds. The mulch softens the raindrops and helps absorb excess moisture so the water does not form a sheet and flow away.

On slopes, even slight ones, a system of swales and berms slows the runoff and helps keep water in place. A swale is a slight depression made along the contour of the slope, while the berm is the raised area beneath the swale, also along the contour line of the slope. The swale will collect extra water and be a place where plants requiring extra moisture can be planted. When water is colleted in a swale, erosion will not occur.

Adding good amounts of compost to planting areas will make the soil more friable and better able to retain moisture.

Terracing on slopes make level planting areas where water will be retained to minimize erosion.

Hard surfaces, such as driveways or parking areas, can create a great deal of runoff so the edges should be contoured to catch the runoff. This runoff can be used to advantage to make moister planting areas.

Roofs also create an enormous amount of runoff. Catch this water in a rain barrel for later use as irrigation water or create piping or shallow ditches to move water by gravity to planting areas away from the house or building.