Total Drawdown In Pumping Well Expressed Given Factors Related To Hydraulic Characteristics Calculator

Total Drawdown Formula:

\[ s_t = B \times q + (C \times q^2) \]

Factors Related To Hydraulic Characteristics (B):

Factors Related To Characteristics Of The Well (C):

Pumping Rate (q):

m³/s

Total Drawdown (sₜ):

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1. What is Total Drawdown?

Total Drawdown is the reduction in hydraulic head observed at a well in an aquifer, typically due to pumping a well as part of an aquifer test or well test. It represents the combined effects of aquifer characteristics and well construction on water level decline.

2. How Does the Calculator Work?

The calculator uses the Total Drawdown formula:

\[ s_t = B \times q + (C \times q^2) \]

Where:

\( s_t \) — Total Drawdown (m)
\( B \) — Factors related to Hydraulic Characteristics of the aquifer
\( C \) — Factors related to Characteristics of the Well
\( q \) — Pumping Rate (m³/s)

Explanation: The equation accounts for both linear and quadratic relationships between pumping rate and drawdown, representing aquifer loss and well loss components respectively.

3. Importance of Total Drawdown Calculation

Details: Accurate drawdown estimation is crucial for well design, pump selection, determining sustainable yield, and assessing aquifer performance during pumping tests.

4. Using the Calculator

Tips: Enter hydraulic characteristics factor (B), well characteristics factor (C), and pumping rate (q) in m³/s. All values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What do the B and C factors represent?
A: B represents aquifer characteristics (transmissivity, storage coefficient), while C represents well characteristics (well efficiency, construction quality).

Q2: How are B and C factors determined?
A: These factors are typically determined through step-drawdown tests or aquifer performance tests by analyzing drawdown data at different pumping rates.

Q3: What is typical range for drawdown values?
A: Drawdown values vary widely depending on aquifer properties and pumping rates, typically ranging from a few centimeters to several meters.

Q4: Why does the equation include a quadratic term?
A: The quadratic term (C×q²) accounts for turbulent flow and well losses that increase disproportionately with higher pumping rates.

Q5: When is this equation most applicable?
A: This equation is particularly useful for analyzing step-drawdown test data and predicting drawdown at different pumping rates for well design.