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The drawdown in aquifer calculation determines the maximum lowering of the groundwater table caused by pumping or artesian flow, taking into account the efficiency of the well. It provides a crucial measure of how effectively a well is performing in extracting groundwater.
The calculator uses the formula:
Where:
Explanation: The formula calculates the actual drawdown in the aquifer by multiplying the measured drawdown inside the well by the well's efficiency factor.
Details: Accurate drawdown calculation is essential for determining well performance, assessing aquifer characteristics, designing pumping systems, and managing groundwater resources effectively.
Tips: Enter well efficiency (typically between 0 and 1) and the measured drawdown inside the well in meters. Both values must be positive numbers.
Q1: What is well efficiency?
A: Well efficiency refers to the ratio of the drawdown in the aquifer at the radius of the pumping well to the drawdown inside the well, indicating how effectively the well transmits water from the aquifer.
Q2: What are typical well efficiency values?
A: Well efficiency typically ranges from 0.6 to 0.8 (60-80%), though this can vary based on well construction, aquifer characteristics, and well maintenance.
Q3: Why is drawdown measurement important?
A: Drawdown measurement helps determine the sustainable yield of a well, assess aquifer properties, and identify potential issues with well performance or clogging.
Q4: How is drawdown inside the well measured?
A: Drawdown is typically measured using pressure transducers or manual water level measurements before, during, and after pumping tests.
Q5: What factors affect well efficiency?
A: Well efficiency is affected by well design, screen characteristics, development methods, aquifer properties, and the degree of well clogging or incrustation over time.