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Microdams

…also called, Net & Pan, bunds, Demilunes or Zai pits.

Permaculture is a design philosophy that emphasizes sustainable and regenerative practices to create harmonious ecosystems. In arid regions, where water scarcity is a significant challenge, permaculturists often use microdams in the form of “net and pan” or “bunds,” to enhance water retention and improve soil and vegetation. Microdams are small-scale earthworks designed to capture and store rainwater, allowing it to slowly infiltrate the soil and benefit the surrounding landscape.

Digging net & pan microdams in a degraded landscape by the Just diggit project.
The results are obvious. This landscape can start living again. Great work by the Just diggit project.

How Microdams Work:

Microdams are typically constructed in natural drainage channels or contour lines on the land. They are simple, low-cost structures that can be built using shovels and other basic tools. The key components of microdams include:

  1. Bunds or Contour Lines: Bunds are small ridges or embankments constructed along the contour of the land. They act as barriers to slow down and retain rainwater runoff.
  2. Net and Pan System: The microdams create a “net and pan” effect, catching water and allowing it to infiltrate the soil within the enclosed area (pan) between the bunds. This maximizes water retention and reduces erosion.
  3. Vegetation: Microdams are often planted with a variety of drought-resistant and native vegetation, which further enhances water retention and prevents soil erosion. The plants help to stabilize the bunds and increase the area’s overall ecological diversity.

Benefits of Microdams in Arid Regions

  1. Water Conservation: By capturing rainwater runoff, microdams help conserve precious water resources, especially in arid regions with limited rainfall.
  2. Improved Soil Moisture: The net and pan system allows rainwater to slowly infiltrate the soil, recharging groundwater and increasing soil moisture levels. This benefits plants and crops during dry periods.
  3. Enhanced Vegetation Growth: With improved water availability, vegetation within the microdam area thrives, promoting biodiversity and providing food and habitat for wildlife.
  4. Erosion Control: Microdams reduce soil erosion by slowing down and trapping water, preventing it from carrying away topsoil and nutrients.
  5. Sustainable Agriculture: In arid regions where conventional agriculture can be challenging, microdams may help to provide a reliable and sustainable water source for small-scale farming and gardening.
  6. Microclimate Creation: The vegetation in and around the microdam area creates a microclimate that is more favorable for plant growth, resulting in a green oasis amidst arid surroundings.
  7. Flood Mitigation: During heavy rainfall, microdams can help control runoff and prevent flooding downstream by storing excess water.
  8. Groundwater Recharge: As rainwater infiltrates the soil within the microdam area, it contributes to recharging the groundwater, which can be vital for maintaining well levels and other water sources.

Microdams are an excellent example of how permaculture principles can be applied to create sustainable solutions for water management in arid regions. They demonstrate the power of working with nature to conserve water, enhance soil health, and foster ecological resilience in challenging environments.

Worthwhile videos

https://www.youtube.com/watch?v=8hq0uMCNGYg&pp=ygUNZGlnZ2luZyBidW5kcw%3D%3D

https://youtu.be/uHDSTCmQ8jY

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