Groundwater and Water tables 101: Basic Things to Know Before you Drill a Well

//Groundwater and Water tables 101: Basic Things to Know Before you Drill a Well

Groundwater and Water tables 101: Basic Things to Know Before you Drill a Well

Are you planning on drilling a well? Before you pick up that shovel (or, more likely, call that well-drilling company), there are a few things you need to know that can help you improve the flow and quality of your new water source.

Plan your water supply

You can’t just drill in any convenient location and expect that there will be a strong enough flow of clean and accessible water. Before you start drilling, you should consult a few resources to help you determine the best location. For instance, in some cases, you may be able to find topographical maps that can help you identify where geological features (like aquifers and the water table) will be. This will help you determine where your well will be the most successful, as well as the locations where drilling the well will be cheaper. You can also employ a water surveyor to help you identify things like groundwater depth, potential yield, and suitability.

What will you need to look for before you start drilling?

1) Your water requirements

You will need to know your own household’s water requirements before you start drilling your well. This will impact the construction of the well along with its location. A higher water demand will require a larger borehole and casing size, which will increase the cost of your well. Just remember that calculating the right amount of water and flow means factoring in your everyday water use (for drinking, cooking, bathtubs and showers, dishwashers and washing machines, toilets, etc.), as well as seasonal use (watering lawns and gardens, washing cars, filling swimming pools, flooding skating rinks, etc.), and (in some cases) fire protection.

2) Water availability

You don’t just need to know that there is water available for your well; you also need to know where the best water access point is. Surveying can help you identify this, as well as any available geological or topographical maps. These can help you identify how far down the water table is, what the groundwater flow is, where the aquifers are, what types of aquifers you have access to, and how deep you need to drill your well to ensure the appropriate static water level (which will also dictate how powerful a pump you need). This information will help prevent you from ending up with a dry or low-yielding well that could cost you a lot more money in the long run.

3) Aquifer types

A successful well is going to tap into an aquifer—an underground deposit of permeable rock or loose material that channels water and is thus able to produce useful water quantities for your well. You will not only need to establish where the best aquifer is, but also what type of aquifer it is. Aquifers can be confined or unconfined, and consolidated or unconsolidated. Unconsolidated aquifers are composed of porous media that allows water to pass between grains. Consolidated aquifers are still composed of porous media, but the grains of which are cemented together. Unconfined aquifers are not confined by rock layers and are only bound by the water table. Confined aquifers (artesian aquifers) lie beneath impermeable materials.

The type of aquifer you choose to drill your well into should be based on required flow rates and water levels, as well as on potential contamination sources; however, the type of aquifer will also impact the price of your well. For instance, unconfined aquifers are often unconsolidated and closer to the surface, which makes them easier and less deep to drill; however, they are more susceptible to contamination due to their proximity to the surface and their porous nature. Confined aquifers are most often consolidated, which seals them off from surface contaminants, but which also requires more expensive drilling. However, confined aquifers, due to their depth and confining pressure, cause the static water level to rise above the top of the aquifer. In some cases, the static water level will rise above the ground surface, forming a flowing artesian well.

Ready to start planning your well?

For the best results, contact American Water Surveyors (AWS) for information about well drilling that may impact you, including information on legislation and the latest technology, as well as for help finding the best place to drill your well.

By |2019-04-04T15:12:41+00:00April 4th, 2019|Uncategorized|