Posted on

Quantifying Hydraulic Conductivity: Slug Test

Objectives: Quantify hydraulic conductivity in an unconfined aquifer based on slug test data of changes in water levels over time.

1.  The biggest unknown in groundwater problems is knowing the hydraulic conductivity of an aquifer.  While there are multiple methods available for quantifying hydraulic conductivity one of the most popular methods is the slug test.  This method artificially changes the water level in a well and monitors the response back to the static level.  Using the data provided below and foldable aquifer model address the following problems.

Table1. Time vs drawdown data.

Time (sec) H-h/(H-Ho)
1 1
10 0.89
20 0.75
30 0.64
50 0.3
100 0.28
120 0.2
180 0.08
200 0.05
300 0.02

A. Quantify the hydraulic conductivity using the Hvorslev method.   

B. Based on the value of hydraulic conductivity above determine if this geologic unit makes a better aquifer or confining unit.   Please explain your answer.

Foldable Aquifer ModelDownload

Below is a second class problem (PDF)
Slug Test Class Problem II
Download
Creative Commons License


This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Posted on

Three Point Problem

Objectives: Identify the direction of groundwater flow in two dimensions and quantify the specific discharge in an unconfined aquifer.

1. The following problem contains of an unconfined limestone aquifer with three monitoring wells.  The monitoring wells are positioned at each of the corners of the triangular aquifer.  Using the water levels shown in wells complete the following tasks.  

A. Determine the direction of groundwater flow based on the water levels in wells A-C. 

B.  Calculate the groundwater gradient across the unconfined aquifer.

C.  Quantify the specific discharge (q) in the unconfined aquifer.

Foldable Aquifer ModelDownload
Creative Commons License


This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Posted on

Hydraulic Head Across Aquifers

Objectives: Determine the hydraulic head across an aquifer system with two distinct hydraulic conductivities.


1. As water flow from one aquifer to another aquifer with differing hydraulic conductivities there must be a change in hydraulic head or a change in discharge.  In the problem below, we are going to assume that water flow from Well A to Well C, through a two-aquifer system.  Both aquifers are confined by an upper shale unit and the discharge (Q) through the aquifers is 20 m3/day.   Using the foldable aquifer model address the following problems.

A. Determine the hydraulic head in Well B. 

B.  Determine the hydraulic head in Well C.

C.  Identify if the aquifer at Well C is confined or unconfined based on the water level in the well.

Foldable Aquifer ModelDownload
Creative Commons License


This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.