Choosing the Right Well Type

Types of Water Wells

Dug Wells Dug wells are one of the oldest types of wells and are created by excavating a hole in the ground until the water table is reached. They are typically shallow, ranging from 10 to 30 feet deep. These wells are usually lined with stones, bricks, or concrete to prevent collapse. Dug wells are relatively easy and inexpensive to construct but are more prone to contamination and may have a lower water yield compared to other types.

Driven Wells Driven wells are constructed by driving a small-diameter pipe into the ground, usually in sandy or loose soil. These wells are typically 30 to 50 feet deep and have a driven point at the bottom that filters out sand and particles. Driven wells are more durable and provide cleaner water than dug wells, but their depth is limited by the soil type and can only be used where the water table is high.

Drilled Wells Drilled wells are created using drilling rigs that can penetrate deep into the earth, reaching depths of several hundred feet. These wells are lined with casing to prevent collapse and contamination. Drilled wells can access water from deeper aquifers, providing a more reliable and clean water source. They are the most expensive to construct due to the specialized equipment and labor required, but they offer the highest water yield and quality.

Factors to Consider

Water Demand and Usage Consider the amount of water required for your household, agricultural, or industrial needs. Drilled wells are best suited for high-demand situations due to their ability to provide a continuous and abundant water supply. For lower water needs, such as for a small home or garden, a dug or driven well may suffice.

Soil and Rock Type The type of soil and rock in your area will significantly influence the choice of well. Dug wells are suitable for areas with soft soil but are less effective in rocky terrain. Driven wells work well in sandy or loose soil but are ineffective in rocky conditions. Drilled wells are versatile and can penetrate through various soil and rock types, making them suitable for most locations.

Depth of Water Table The depth of the water table in your area will determine the type of well you can install. In areas with a shallow water table, dug and driven wells can be effective. However, if the water table is deep, a drilled well will be necessary to reach the water source.

The Installation Process

Planning and Design

Selecting the Well Location Choosing the right location for your well is crucial. The site should be easily accessible for drilling equipment and far from potential sources of contamination, such as septic systems, livestock areas, and chemical storage. The location should also be chosen based on hydrogeological surveys to ensure a sufficient water supply.

Designing the Well System The well system design includes selecting the appropriate well type, determining the depth and diameter of the well, and choosing suitable materials for casing and lining. A well-designed system will ensure long-term efficiency, water quality, and ease of maintenance.

Drilling

Types of Drilling Methods

• Rotary Drilling: This method uses a rotating drill bit to bore through the earth. It is suitable for most soil and rock types and can reach significant depths.
• Percussion Drilling: Also known as cable-tool drilling, this method involves repeatedly raising and dropping a heavy drill bit to break and penetrate the ground. It is effective in hard rock formations but is slower than rotary drilling.

Step-by-Step Drilling Process

1. Site Preparation: Clear the area and set up the drilling rig.
2. Drilling: Begin drilling using the chosen method until the desired depth is reached.
3. Casing Installation: Insert casing to prevent the well walls from collapsing and to protect the water source from contamination.
4. Well Screen Installation: Install a well screen at the bottom of the casing to filter out sediment and allow water to flow into the well.
5. Gravel Packing: Add gravel around the well screen to improve water flow and filtration.

Well Construction

Casing and Lining The casing is a crucial component that maintains the structural integrity of the well and prevents contaminants from entering the water supply. It is typically made of steel, plastic, or concrete and is installed from the surface to the bottom of the well.

Installing the Well Screen The well screen is placed at the bottom of the well to allow water to enter while keeping out sand and other particles. It is usually made of stainless steel or plastic and comes in various designs, such as slotted, perforated, or continuous slot screens.

Development and Pump Installation

Well Development Techniques Well development involves cleaning out fine particles and debris from the well to improve water flow. Techniques include:

• Surging: Alternately injecting and removing water to agitate and clean the well.
• Airlifting: Using compressed air to lift water and debris out of the well.
• Chemical Treatment: Using chemicals to dissolve and remove clogging materials.

Installing the Pump System The final step is installing a pump to draw water from the well. The type of pump depends on the well depth and water demand. Common types include:

• Submersible Pumps: Installed inside the well and suitable for deep wells.
• Jet Pumps: Installed above ground and ideal for shallow wells.
• Hand Pumps: Manual pumps used for small-scale water needs or as a backup system.