Using Above-Ground Objects to Raise the Lower Edge of a Groundsheet for Rainwater Collection

Raising the lower edge of a groundsheet with above-ground objects is a practical and easy way to create a simple, leak-resistant dam for collecting rainwater.

• Objects such as logs, rocks, sandbags, bricks, or even stacked lumber are placed at the lowest end of the sloped groundsheet.

• The lower end of the groundsheet is then draped over these objects, effectively forming a barrier that allows rainwater to pool on top of the sheeting.

• By anchoring the sheet’s edges down on the outer (downslope) side of the objects, you ensure water cannot escape underneath.

• : No excavation required—reduces labor and is ideal for temporary or rapid-deployment setups.

• : Materials can be removed or repositioned easily.

• : Less disturbance to the soil and less chance of undermining compared to traditional earthen dams.

• : Works in rocky terrain or areas where digging is not practical.

1. :

   • Place your plastic sheet or tarp on a smooth surface, making sure it slopes toward the intended lower (collection) end.

2. :

   • Place sturdy above-ground materials (e.g., logs, sandbags) in a line across the downslope edge where you want water to accumulate.

   • Build the “dam” high enough for the expected water depth, but with enough mass to resist moving when full.

3. :

   • Pull the lower end of the groundsheet over the dam objects, so the sheet covers both the inside (uphill side) and wrap a short distance down the front (downslope side).

4. :

   • Place additional rocks, sandbags, or other weights on the grounded flap of plastic to prevent water from leaking under (“piping” beneath the dam).

   • Ensure a snug fit—water should pool and push the plastic tight against the objects, creating a seal.

5. Optional: Add a Drain or Overflow:

   • For water transfer or to prevent overtopping, install a hose or a small pipe through the dam (under the plastic) at the lowest point.

• Use UV-resistant plastic for durability if collecting over extended periods.

• Prioritize objects with smooth edges to avoid tearing the groundsheet.

• Regularly inspect for leaks or slippage—re-anchor as needed after large rain events.

• Clean debris from the sheet to maximize water quality and flow.

• Emergency water collection in fields, gardens, or construction sites.

• Mobile setups for camping or temporary livestock watering points.

• DIY rainwater harvesting where building a permanent dam is impractical.

By utilizing above-ground objects to form the dam and covering them with the groundsheet, you achieve a fast, flexible, and effective means to collect and store rainwater with minimal resources and setup time.