Earth Partnership for Schools


Soil moisture and drainage have a direct bearing on the species and woodland communities that grow on your site. Soil drainage indicates a relationship to how much water is in the soil and the influence of topography on the water. Factors such as soil texture and type and climatic patterns influence the amount of water in the soil as well. Soil moisture indicates the amount of water available for plant use. Identifying the topography and drainage of your site will help you determine potential moisture gradients, from wet to dry, located on your site. In this activity, you will estimate, through regular observations and simple field tests, moisture and drainage conditions on your site.

  1. Soil Texture / Drainage:
  • Directions:
    • Walk around the school grounds at different times of the year and at different times during a rain cycle.
    • Observe where water collects and where water drains quickly, check soil moisture on slopes, under trees, and in specific microclimates. Compare the descriptions of the following gradients with your observations of your school landscape. Look for areas on the extreme ends of the gradient. It is these areas that greatly restrict plant choices.
      • Flooded - Areas where standing water is present most of the growing season.
      • Wet - Areas where standing water is present most of the growing season, except during times of drought. Wet areas are found at the edges of ponds, rivers, streams, ditches, and low spots. Wet conditions exist on poorly drained soils, often with a high clay content.
      • Moist - Areas where the soil is damp. Occasionally, the soil is saturated and drains slowly. These areas usually are at slightly higher elevations than wet sites. Moist conditions may exist in sheltered areas protected from sun and wind.
      • Well-drained - Areas where rain water drains readily, and puddles do not last long. Moisture is available to plants most of the growing season. Soils usually are medium textures with enough sand and silt particles to allow water to drain through the soil.
      • Dry - Areas where water drains rapidly through the soil. Soils are usually coarse, sandy, rocky or shallow. Slopes are often steep and exposed to sun and wind. Water runs off quickly and does not remain in the soil.

  1. Drainage Field Test: This field test will help you to determine if you have a poorly drained soil on your site.
  • Materials needed:
    • shovel
    • bucket of water
    • stopwatch
  • Directions: Dig a hole about one foot deep, and fill it with water. If it takes more than one hour to drain, you may have poorly drained soil.
  1. Moisture Field Test : For this activity, you will estimate how much moisture is in the soil through simply feeling the soil at field capacity. Field capacity is the amount of moisture held in the soil after water has drained away two or three days after a rainstorm.
  • Materials needed:
    • shovel
    • paper towels
  • Directions:
    • Dig a hole about 8" deep two or three days after the rain has saturated the soil.
    • Take a small handful of soil from the bottom of the hole. Then feel the soil to estimate its moisture content. Determine if the soil feels:
      • Dry - The soil will feel dry, will not stay in a ball or is very sandy.
      • Moist - The soil will feel moist in your hand. Water will not squeeze out.
      • Wet or saturated - When squeezed in a ball water is left in your hand.