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Drawdown in aquifer refers to the lowering of the groundwater table caused by pumping or artesian flow. It represents the difference between the original water level and the current water level in a well or aquifer system.
The calculator uses the formula:
Where:
Explanation: This formula calculates the actual drawdown in the aquifer by subtracting well losses from the total observed drawdown at the well.
Details: Accurate drawdown calculation is crucial for understanding aquifer characteristics, determining well efficiency, and managing groundwater resources effectively.
Tips: Enter total drawdown and well loss values in meters. Both values must be non-negative numbers. The calculator will compute the change in drawdown in the aquifer.
Q1: What is the difference between total drawdown and aquifer drawdown?
A: Total drawdown includes both the drawdown in the aquifer and well losses, while aquifer drawdown represents only the actual lowering of the water table in the formation.
Q2: Why is it important to account for well losses?
A: Well losses account for energy losses as water enters the well, providing a more accurate measurement of the actual aquifer response to pumping.
Q3: What factors contribute to well losses?
A: Well losses include friction losses in the well screen, turbulent flow near the well, and any clogging or damage to the well structure.
Q4: How is well loss typically determined?
A: Well loss is often determined through step-drawdown tests where pumping rates are increased incrementally and drawdown is measured at each step.
Q5: What are typical values for drawdown in aquifers?
A: Drawdown values vary widely depending on aquifer properties, pumping rates, and duration. They can range from a few centimeters to several meters.