Single-Well Injection-Drift Test to Estimate Groundwater Velocity

Area of Science:

• Hydrogeology
• Environmental Science

Background:

• Traditional groundwater velocity estimation methods are often time-consuming and expensive, requiring extensive fieldwork.
• The extraction phase in conventional tests can be a significant bottleneck in terms of cost and duration.

Purpose of the Study:

• To present a novel, simplified algebraic equation for estimating groundwater velocity.
• To validate a new single-well injection-drift test method against established multi-well techniques.

Main Methods:

• A single-well injection-drift test involving forced-gradient injection of tracer-amended water.
• Monitoring conservative solute tracers during natural-gradient drift back through the well.
• Analyzing breakthrough curve data to determine mean tracer travel times.
• Comparing single-well results with dual-well (1D) and multi-well (2D) tracer transport data.

Main Results:

• The single-well injection-drift test estimated groundwater velocity at approximately 0.64 ft/day.
• Dual-well analysis yielded a groundwater velocity of 0.55 ft/day.
• Multi-well analysis indicated a groundwater velocity of 0.60 ft/day.
• Results from the single-well method showed excellent agreement with dual- and multi-well analyses.

Conclusions:

• The developed algebraic equation and single-well injection-drift test provide a simple, rapid, and effective means to estimate groundwater velocity.
• The method eliminates the need for a costly and time-consuming extraction phase.
• This approach offers a validated and efficient alternative for hydrogeological investigations.