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- Pumping Tests
- Analysis and Evaluation of Pumping Test Data
- Analysis and Evaluation of Pumping Test Data

The first edition of this book appeared as No. The aims of ILRI are: collect information on land reclamation and improvement from all over the world; - To disseminate this knowledge through publications, courses, and consultancies; - To contribute - by supplementary research - towards a better understanding of the land and water problems in developing countries. All rights reserved. This book or any part thereof may not be reproduced in any form without written permission of the publisher. This is the second edition of Analysis and Evaluation ofpumping Test Data.

An aquifer test or a pumping test is conducted to evaluate an aquifer by "stimulating" the aquifer through constant pumping , and observing the aquifer's "response" drawdown in observation wells.

Aquifer testing is a common tool that hydrogeologists use to characterize a system of aquifers, aquitards and flow system boundaries. A slug test is a variation on the typical aquifer test where an instantaneous change increase or decrease is made, and the effects are observed in the same well.

This is often used in geotechnical or engineering settings to get a quick estimate minutes instead of days of the aquifer properties immediately around the well. Aquifer tests are typically interpreted by using an analytical model of aquifer flow the most fundamental being the Theis solution to match the data observed in the real world, then assuming that the parameters from the idealized model apply to the real-world aquifer.

In more complex cases, a numerical model may be used to analyze the results of an aquifer test, but adding complexity does not ensure better results see parsimony.

Aquifer testing differs from well testing in that the behaviour of the well is primarily of concern in the latter, while the characteristics of the aquifer are quantified in the former. Aquifer testing also often utilizes one or more monitoring wells , or piezometers "point" observation wells. A monitoring well is simply a well which is not being pumped but is used to monitor the hydraulic head in the aquifer. Typically monitoring and pumping wells are screened across the same aquifers.

Most commonly an aquifer test is conducted by pumping water from one well at a steady rate and for at least one day, while carefully measuring the water levels in the monitoring wells. When water is pumped from the pumping well the pressure in the aquifer that feeds that well declines. This decline in pressure will show up as drawdown change in hydraulic head in an observation well. Drawdown decreases with radial distance from the pumping well and drawdown increases with the length of time that the pumping continues.

Additional aquifer characteristics which are sometimes evaluated, depending on the type of aquifer, include:. An appropriate model or solution to the groundwater flow equation must be chosen to fit to the observed data. There are many different choices of models, depending on what factors are deemed important including:.

Nearly all aquifer test solution methods are based on the Theis solution; it is built upon the most simplifying assumptions. Other methods relax one or more of the assumptions the Theis solution is built on, and therefore they get a more flexible and more complex result. Lubin , for two-dimensional radial flow to a point source in an infinite, homogeneous aquifer. It is simply. The well function is approximated by the infinite series. Typically this equation is used to find the average T and S values near a pumping well , from drawdown data collected during an aquifer test.

This is a simple form of inverse modeling, since the result s is measured in the well, r , t , and Q are observed, and values of T and S which best reproduce the measured data are put into the equation until a best fit between the observed data and the analytic solution is found. Even though these assumptions are rarely all met, depending on the degree to which they are violated e. Steady-state radial flow to a pumping well is commonly called the Thiem solution, [2] it comes about from application of Darcy's law to cylindrical shell control volumes i.

In this expression h 0 is the background hydraulic head , h 0 - h is the drawdown at the radial distance r from the pumping well, Q is the discharge rate of the pumping well at the origin , T is the transmissivity , and R is the radius of influence, or the distance at which the head is still h 0. These conditions steady-state flow to a pumping well with no nearby boundaries never truly occur in nature, but it can often be used as an approximation to actual conditions; the solution is derived by assuming there is a circular constant head boundary e.

Of critical importance in both aquifer and well testing is the accurate recording of data. Not only must water levels and the time of the measurement be carefully recorded, but the pumping rates must be periodically checked and recorded. The US Geological Survey has some very useful free references on pumping test interpretation:.

More book titles can be found in the further reading section of the hydrogeology article, most of which contain some material on aquifer test analysis or the theory behind these test methods. From Wikipedia, the free encyclopedia. Transactions, American Geophysical Union.

Leipzig: J. Gebhardt: Darcy's law Groundwater flow equation Theis equation Thiem equation Hooghoudt equation.

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An aquifer test or a pumping test is conducted to evaluate an aquifer by "stimulating" the aquifer through constant pumping , and observing the aquifer's "response" drawdown in observation wells. Aquifer testing is a common tool that hydrogeologists use to characterize a system of aquifers, aquitards and flow system boundaries. A slug test is a variation on the typical aquifer test where an instantaneous change increase or decrease is made, and the effects are observed in the same well. This is often used in geotechnical or engineering settings to get a quick estimate minutes instead of days of the aquifer properties immediately around the well. Aquifer tests are typically interpreted by using an analytical model of aquifer flow the most fundamental being the Theis solution to match the data observed in the real world, then assuming that the parameters from the idealized model apply to the real-world aquifer. In more complex cases, a numerical model may be used to analyze the results of an aquifer test, but adding complexity does not ensure better results see parsimony.

The first edition of this book appeared as No. The aims of ILRI are: collect information on land reclamation and improvement from all over the world; - To disseminate this knowledge through publications, courses, and consultancies; - To contribute - by supplementary research - towards a better understanding of the land and water problems in developing countries. All rights reserved. This book or any part thereof may not be reproduced in any form without written permission of the publisher. This is the second edition of Analysis and Evaluation ofpumping Test Data.

In order to determine the groundwater resources and potentials of the Khanewal District of Pakistan, a geophysical method in combination with pumping test data were used. An analytical relationship between the aquifer parameters interpreted from surface geoelectrical method and pumping test was established in order to estimate aquifer parameters from surface measurements where no pumping tests exist. For the said purpose, 48 geoelectric investigations were carried out using Schlumberger vertical electrical sounding VES. Seven of the soundings were conducted where pumping tests had been carried out at borehole sites.

Abstract: Single well test is more common than aquifer test with having observation well, since the advantage of single well test is that the pumping test can be conducted on the production well with the absence of observation well. A kind of single well test,which is step-drawdown test used to determine the efficiency and specific capacity of the well, however in case of single well test it is possible to estimate Transmissivity, but the other parameter which is Storativity is overestimated, so the aim of this study is to analyze four pumping test data located in KAWRGOSK area by using cooper-Jacob's time drawdown approximation of Theis method to estimate the aquifer parameters, also in order to determine the reasons which are affecting the reliability of the Storativity value and obtain the important aspect behind that in practice. Keywords: aquifer parameters, single well test, Cooper-Jacob's straight line method 1. The most important method to estimate the aquifer parameters are testing with having observation well, but it's cost more than conducting pumping test without observation well which is called single well test, so that since the last decade there are many experiences that are tried to discover a method to estimate the aquifer parameters through analyze single well test data such as choi,Byung-soo, which tried to find out the Storativity by determining skin factor and effective wellbore storage, and the method of P. Ballukraya, et al, it derived an equation to estimate Storativity by recovery test, Also M.

Recently, composite analysis CA , which simultaneously analyzes all drawdown data from multiple observation wells, has been applied to determine the hydraulic parameters of an unconfined aquifer. Moench claimed that the value of specific yield S y determined from non-composite analysis nonCA is sometimes unrealistically low as compared with that obtained by water-balance calculation, and results from CA are better representative of aquifer properties than those from nonCA. The results show that the mean estimates of hydraulic conductivity and S y determined from CA are close to those determined from nonCA.

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## 2 Comments

## Bartlett A.

more modern method of analyzing pumping tests in unconfined aquifers with Analyzing and evaluating pumping test data, however, is as much an art as a.

## Alix R.

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