Water is pumped from a well tapping an unconfined aquifer at a rate of 2400 m³/day. A no-drawdown boundary exists at a distance of 5 km from the well centre. Assuming the well to be fully penetrating, compute the steady state drawdown at the well face. Given: Initial saturated thickness = 50 m, hydraulic conductivity = 20 m/day, effective well radius = 1 m.

Structural Analysis
6th Edition
ISBN:9781337630931
Author:KASSIMALI, Aslam.
Publisher:KASSIMALI, Aslam.
Chapter2: Loads On Structures
Section: Chapter Questions
Problem 1P
icon
Related questions
icon
Concept explainers
Question
**Example Problem on Aquifer Pumping and Steady State Drawdown Calculation**

**Problem Statement:**

Water is pumped from a well tapping an unconfined aquifer at a rate of 2400 m³/day. A no-drawdown boundary exists at a distance of 5 km from the well center. Assuming the well to be fully penetrating, compute the steady-state drawdown at the well face. 

**Given Data:**
- Initial saturated thickness \(b_0\) = 50 m
- Hydraulic conductivity \(K\) = 20 m/day
- Effective well radius \(r_w\) = 1 m

**Step-by-Step Solution:**

1. **Understand the given data and parameters:**

   - **Pumping rate (Q):** This is the rate at which water is extracted from the well, given as 2400 m³/day.
   - **No-drawdown boundary distance (R):** This is the distance at which there is no drop in the water table, located 5 km (5000 meters) from the well center.
   - **Initial saturated thickness (b_0):** The initial depth or thickness of the aquifer from which water is being pumped, given as 50 m.
   - **Hydraulic conductivity (K):** This is the measure of the aquifer's ability to transmit water, given as 20 m/day.
   - **Effective well radius (r_w):** The radius of the well where the drawdown is to be calculated, given as 1 meter.

2. **Apply the formula for steady-state drawdown in an unconfined aquifer:**

   The general formula is:

   \[ s = \frac{Q}{2 \pi K} \ln\left(\frac{R}{r_w}\right) \]

3. **Substitute the given values into the formula:**

   - Pumping rate (Q) = 2400 m³/day
   - Hydraulic conductivity (K) = 20 m/day
   - No-drawdown boundary distance (R) = 5000 m
   - Effective well radius (r_w) = 1 m

   \[ s = \frac{2400}{2 \pi \times 20} \ln\left(\frac{5000}{1}\right) \]

4. **Calculate the logarithm term:**

   \[ \ln\
Transcribed Image Text:**Example Problem on Aquifer Pumping and Steady State Drawdown Calculation** **Problem Statement:** Water is pumped from a well tapping an unconfined aquifer at a rate of 2400 m³/day. A no-drawdown boundary exists at a distance of 5 km from the well center. Assuming the well to be fully penetrating, compute the steady-state drawdown at the well face. **Given Data:** - Initial saturated thickness \(b_0\) = 50 m - Hydraulic conductivity \(K\) = 20 m/day - Effective well radius \(r_w\) = 1 m **Step-by-Step Solution:** 1. **Understand the given data and parameters:** - **Pumping rate (Q):** This is the rate at which water is extracted from the well, given as 2400 m³/day. - **No-drawdown boundary distance (R):** This is the distance at which there is no drop in the water table, located 5 km (5000 meters) from the well center. - **Initial saturated thickness (b_0):** The initial depth or thickness of the aquifer from which water is being pumped, given as 50 m. - **Hydraulic conductivity (K):** This is the measure of the aquifer's ability to transmit water, given as 20 m/day. - **Effective well radius (r_w):** The radius of the well where the drawdown is to be calculated, given as 1 meter. 2. **Apply the formula for steady-state drawdown in an unconfined aquifer:** The general formula is: \[ s = \frac{Q}{2 \pi K} \ln\left(\frac{R}{r_w}\right) \] 3. **Substitute the given values into the formula:** - Pumping rate (Q) = 2400 m³/day - Hydraulic conductivity (K) = 20 m/day - No-drawdown boundary distance (R) = 5000 m - Effective well radius (r_w) = 1 m \[ s = \frac{2400}{2 \pi \times 20} \ln\left(\frac{5000}{1}\right) \] 4. **Calculate the logarithm term:** \[ \ln\
Expert Solution
steps

Step by step

Solved in 3 steps with 2 images

Blurred answer
Knowledge Booster
Field Applications of Hydraulic Conductivity
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
Structural Analysis
Structural Analysis
Civil Engineering
ISBN:
9781337630931
Author:
KASSIMALI, Aslam.
Publisher:
Cengage,
Structural Analysis (10th Edition)
Structural Analysis (10th Edition)
Civil Engineering
ISBN:
9780134610672
Author:
Russell C. Hibbeler
Publisher:
PEARSON
Principles of Foundation Engineering (MindTap Cou…
Principles of Foundation Engineering (MindTap Cou…
Civil Engineering
ISBN:
9781337705028
Author:
Braja M. Das, Nagaratnam Sivakugan
Publisher:
Cengage Learning
Fundamentals of Structural Analysis
Fundamentals of Structural Analysis
Civil Engineering
ISBN:
9780073398006
Author:
Kenneth M. Leet Emeritus, Chia-Ming Uang, Joel Lanning
Publisher:
McGraw-Hill Education
Sustainable Energy
Sustainable Energy
Civil Engineering
ISBN:
9781337551663
Author:
DUNLAP, Richard A.
Publisher:
Cengage,
Traffic and Highway Engineering
Traffic and Highway Engineering
Civil Engineering
ISBN:
9781305156241
Author:
Garber, Nicholas J.
Publisher:
Cengage Learning