Sand point wells work by using a perforated pipe, driven or jetted into a sandy aquifer, to draw water directly from the surrounding saturated sand.
Here's a breakdown of how they function:
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The Sand Point: This is a length of pipe, typically 1.25 to 2 inches in diameter, with a screened or perforated section at the bottom. The perforations allow water to enter the pipe while ideally keeping out sand and larger particles. In areas like Sauble Beach, the aquifer is made of sand, and can extend deep underground (potentially hundreds of feet).
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Installation: The sand point is driven or jetted into the ground until it reaches the water table and the sandy aquifer. Driving involves pounding the pipe into the earth, while jetting uses water pressure to create a pathway.
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Water Extraction: A pump, typically a shallow well jet pump, is connected to the top of the pipe. The pump creates suction, drawing water up from the aquifer through the perforations in the sand point and into the pipe.
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Filtration: The surrounding sand acts as a natural filter, removing larger particles from the water. Some sand may still enter the well, so a filter at the pump is recommended.
Key Considerations:
- Aquifer Type: Sand point wells are best suited for shallow, sandy aquifers. They will not work in areas with bedrock close to the surface or with clay-rich soils.
- Water Quality: Water quality can vary depending on the location and the surrounding environment. Testing the water is crucial to ensure it's safe for consumption.
- Well Depth: Sand point wells are typically shallow, usually less than 25 feet deep. The depth is limited by the suction lift of the pump.
- Yield: The amount of water a sand point well can produce depends on the permeability of the aquifer. Sandy aquifers generally have good permeability.
- Maintenance: Regular maintenance, including cleaning the screen and checking the pump, is important to ensure the well continues to function properly.
In summary, sand point wells are a simple and cost-effective way to access groundwater in areas with suitable sandy aquifers. They rely on a screened pipe inserted into the saturated sand, from which water is pumped to the surface.
