Groundwater Monitoring Wells are essential tools for assessing the quality and quantity of groundwater. These wells help environmental scientists, geologists, and engineers collect valuable data on subsurface conditions, water levels, and potential contaminants. One of the methods used to install these wells is hand augering. While less mechanized than other drilling methods, hand augering is a practical, cost-effective approach, especially in remote or sensitive areas where minimizing environmental disturbance is crucial. This article provides a comprehensive guide to hand augering a groundwater monitoring well, outlining the steps, tools, and best practices involved.
Hand augering involves manually drilling into the ground using a hand auger, a tool designed to bore holes into soil. The process is labor-intensive but can be highly effective in specific situations, such as shallow wells or areas with soft soil conditions. The depth that can be achieved with hand augering typically ranges between 5 to 10 meters, depending on soil type, water table depth, and the physical endurance of the operator.
To successfully hand auger a groundwater monitoring well, the following tools and equipment are essential:
1. Hand Auger: A basic auger consists of a T-handle attached to a shaft with a helical screw blade at the bottom. The blade cuts into the soil as the operator turns the handle, bringing soil to the surface.
2. Auger Extensions: These are used to increase the depth of the hole as the auger progresses downward. Extensions can be added or removed as needed.
3. Shovel: A shovel is useful for clearing loose soil and debris from around the auger hole.
4. Soil Sampling Tools: Depending on the purpose of the well, soil samples may need to be collected at various depths. Tools such as a soil core sampler or a split-spoon sampler are commonly used for this purpose.
5. PVC Pipe or Well Casing: After reaching the desired depth, a PVC pipe or well casing is inserted into the hole to maintain the well structure and prevent collapse.
6. Sand and Bentonite: Sand is used to fill the annular space around the well screen, while bentonite clay is used to seal the well, preventing surface contaminants from entering.
7. Well Screen: A well screen, typically made of slotted PVC or stainless steel, allows water to enter the well while keeping out sediments.
8. Caps and Protective Covers: The well is capped with a protective cover to prevent contamination and ensure safety.
1. Site Selection and Preparation: Choose a location based on the specific monitoring needs and accessibility. Clear the area of vegetation and debris to create a stable working environment.
2. Start Augering: Position the hand auger on the ground and begin turning the handle clockwise. The auger blade will cut into the soil, bringing up loose material. After a few turns, lift the auger out of the hole to remove the soil, then continue the process. Repeat until the desired depth is reached.
3. Adding Extensions: As the hole deepens, attach extensions to the auger shaft to reach greater depths. Ensure that the connections between the auger and the extensions are secure to prevent disconnection during use.
4. Soil Sampling: If soil sampling is required, collect samples at predetermined depths using appropriate tools. Label and store the samples for laboratory analysis.
5. Installing the Well Casing: Once the desired depth is achieved, insert the well casing or PVC pipe into the hole. The well screen should be positioned at the bottom where the water is expected to enter.
6. Backfilling and Sealing: Fill the annular space around the well screen with clean sand to facilitate water entry. Above the sand layer, add a bentonite seal to prevent surface water from contaminating the well.
7. Capping and Securing the Well: After the well is installed, cap the top of the casing to protect it from debris and contaminants. If required, add a protective cover or fence around the well to ensure safety and prevent tampering.
· Safety: Hand augering is physically demanding, so it's essential to take frequent breaks, stay hydrated, and use proper lifting techniques to avoid injury.
· Soil Conditions: Hand augering is best suited for soft soils such as clay, silt, and loose sand. Hard, rocky, or compacted soils may require alternative drilling methods.
· Environmental Impact: Hand augering is a low-impact method, making it ideal for environmentally sensitive areas. Minimize disturbance by carefully managing soil and avoiding contamination of the site.
· Data Accuracy: Ensure accurate depth measurements and proper documentation of the soil samples and well construction details. This data is crucial for reliable groundwater monitoring.
Hand augering is a practical and cost-effective method for installing shallow Groundwater Monitoring Wells. While it requires physical effort and careful planning, the technique offers significant advantages, particularly in remote or sensitive areas. By following the correct procedures and best practices, hand augering can provide reliable access to groundwater, enabling effective monitoring and management of this vital resource.