What size pit is necessary for optimal water gathering?

Pit Design and Construction

When building a pit for a solar still, it’s essential to create a shallow, wide depression rather than a deep, narrow one. A 2-3 foot depth allows for sufficient water collection and evaporation space, while a 4-6 foot diameter provides ample surface area for the still to operate efficiently. The pit should be dug in a location that receives direct sunlight and is protected from wind and precipitation.

Water Collection and Liner Material

The bottom of the pit should be lined with a durable, waterproof material such as a plastic tarp or a layer of clay. This liner will help to prevent water from seeping into the surrounding soil and ensure that the collected water remains clean and free from contaminants. A 1/4 inch layer of sand or small rocks should be placed on top of the liner to create a smooth, even surface for the still’s collection tray.

Placement and Orientation

The pit should be positioned in a location that receives direct sunlight for at least 6 hours a day. The still should be oriented to face the sun, with its collection tray facing downwards to allow for efficient water collection. A slight incline of the still’s collection tray (about 1-2 degrees) will help to promote water flow and prevent stagnation.