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Competency Area 3: Drainage and irrigation AEM

PO 20. Understand the benefits and risks to the environment that are potentially inherent from a drainage system.

The major positive environmental effects and concerns with drainage implementation are:

  • Increased productivity and value of land – wet soils can be used for more intensive land usesImproved trafficability, timeliness, and cost efficiency
  • Reclaim soils laden with salts (in arid regions) or to divert or collect water from other potential contaminant areas (barnyards, septics)
  • Vector control and public health – stagnant waters and wet areas are eliminated that are conducive to disease-causing organisms
  • Reduced erosion – saturated soils cannot adsorb additional water so these may induce more surface runoff and erosion, and saturated sloping soils are less stable

The major negative environmental effects and concerns with drainage implementation are:

  • Land use conversion – wet soils and wetlands converted to agricultural land or other intensive (industrial, urban) land uses
  • Habitat conversion – bio-diverse areas converted to mono-culture ecological systems (corn, soybean fields or houses and lawns)
  • Water quantity manipulations – drainage water discharges may alter receiving stream hydrographs (i.e., extensive uncontrolled surface drainage may increase downstream peak flows and induce flooding)
  • Water quality alterations – water discharged from drainage systems may contain undesirable concentrations of sediment and/or other contaminants that may enter receiving waters, as compared with runoff and leaching which occurs naturally