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Sand Dams & Subsurface Masonry Dams

A sand dam is a reinforced concrete or stone masonry weir built across a seasonal, sandy dry riverbed in arid drylands.

How a Sand Dam Works

Rainy Season: Sand & Water Flow Down River
══════════════════════════════════════════════════════════►
                  [ Coarse Sand Accumulates ]
                  [ Storing 40% Volume Water]
   River Bed  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
              │                               │
              │  REINFORCED CONCRETE WEIR     │
              │  Anchored to Bedrock          │
              └───────────────────────────────┘
  1. Sediment Trapping: Flash floods deposit heavy coarse sand behind the weir.
  2. Artificial Sand Aquifer: Over 1 to 3 rainy seasons, the sand bed stores millions of liters of filtered water (up to 40% by volume).
  3. Zero Evaporation: Underground storage eliminates evaporative loss and mosquito breeding.
  4. Lifespan: 30 to 50+ Years with minimal maintenance.