Rainwater Harvesting, Vol 2, Earthworks by Brad Lancaster

Eight Principles of Successful Rainwater Harvesting

  1. Begin with long and thoughtful observation.
  2. Start at the top of your watershed and work your way down.
  3. Start and simple. 
  4. Slow, spread, and infiltrate the flow of water.
  5. Always plan an overflow route, and manage that overflow as a resource.
  6. Create a living space.
  7. Do more than just harvest water.
  8. Continually reassess your system. 

Berm and Basin (aka swale)

  • Use on land sloped up to 18 degrees.
  • Use native perennial vegetation.
  • Variations: contour berm, boomerang berm, net and pan 


  • Used on steep land.
  • With or without retaining wall.

French Drain

  • Directs stormwater quickly into subsoil.
  • Only with sediment-free water, directly off roof, etc.

Infiltration Basin

  • Collect rainwater for trees and vegetation.
  • Plan for peak overflow.
  • Sunken garden beds.


  • Create micro-climates for seed germination and growth.
  • Use mechanical imprinter for more than 1 acre.


  • Benefits: increase rainwater infiltration, improve soil fertility, reduce evaporative loss, limit soil erosion, suppress weed growth.
  • Variations: vertical mulch.

Permeable Paving

  • Replace large areas of concrete with permeable pavers, gravel, etc.
  • Increases infiltration and reduces rainwater runoff and erosion.

Diversion Swale

  • Swale built slightly off-contour.
  • Gradually diverts rainwater away.
  • Slows, diverts, and promotes infiltration.
  • Variation: spreader drain

Check Dam

  • Slows, spreads, and infiltrates ephemeral watercourses during heavy rain.
  • Use on eroding arroyos, gullies, below culverts, near roads/paths. 
  • Variations: loose rock check dams, wire-encased rock gabions, brush check dam, one rock check dam.


  • Critical component of all earthworks.
  • Plant in or beside all earthworks, always. 

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