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Rainwater Harvesting Methods. What do we need to do with water?. Slow it, Spread it, Sink it!. Brad Lancaster: “Rainwater Harvesting for Drylands and Beyond”. The 8 Principles of Successful Rainwater Harvesting. Berm and Basin. Good for planting trees in!. Planting microbasins. Mulching!.
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What do we need to do with water? Slow it, Spread it, Sink it!
Brad Lancaster: “Rainwater Harvesting for Drylands and Beyond”
Mulching! • Organic Matter (dead plants) • Living Mulch (ground cover) • Rock Mulch
Using hard runoff areas to fill mulched or vegetated retention spaces: paved areas and roads.
Boomerang Berms Endpoints point uphill and are slightly lower, allowing an overflow at one or both ends when basin is full. A good idea to reinforce overflow point with rocks.
Cascading • More, smaller earthworks will spread out flow and stop overloading • Can combine several techniques
Boomerang berms to focus water around trees and contour swales below on hillsides (can link to keyline dams).
Swales/ Berm and Basins on Different Slopes • The steeper the slope, the narrower earthworks need to be and the more of them we need. • On very steep slopes they must be reinforced (with rock or concrete).
Overflows • Pipes can be necessary if a road goes over the top • Can also use a permeable stone “wet crossing”
Net and Pan Upper half of pan is catchment surface draining water to lower half where water infiltrates into tree root zone.
Check dams Water moving downslope carries with it sediment and organic matter. The faster it moves, the more it erodes and carries. In gullies, erosion can happen fast. Check dams are barriers that make the water slow and pool, depositing its sediment behind the dam, forming a terrace.
Planting into fertile sediment behind dam is recommended – it will stabilize the terrace and is often fertile and good for growing.
Check dams can be used inside diversion swales to control flow rate and erosion
