Results 171 to 180 of about 8,442,772 (211)

Interpretation of Step-Drawdown Tests with the Differential Evolution Approach

Journal of Hydrologic Engineering - ASCE, 2022
A step-drawdown test is a common hydrogeological investigation tool employed for identifying the hydraulic characteristics of an aquifer as well as assessing the efficiency of the pumping conditions. Several graphical and optimization-based solution techniques have been devised for analyzing data sets obtained from step-drawdown tests to retrieve ...
A Ufuk Şahin, Emin Ciftci
exaly   +4 more sources

An approach to interpretation of step drawdown tests

Hydrogeology Journal, 2006
To understand the behaviour of drawdown with discharge under site-specific conditions, a step drawdown test (SDT) was conducted on a tubewell in alluvium near Delhi, India, and the data were analyzed to find the value of well efficiency. The entrance velocity of groundwater into the well screen was computed to see if it exceeded the safety limit of 0 ...
Shashank Shekhar
exaly   +2 more sources

The analysis and planning of step drawdown tests

Quarterly Journal of Engineering Geology and Hydrogeology, 1977
Summary A step drawdown test is a pumping test in which the drawdown in a well is observed while the discharge rate from the well is increased in steps. The methods of analysis and the criteria for planning step drawdown tests are discussed and evaluated in order to produce an optimum test programme and a comprehensive test analysis.
Lewis Clark
exaly   +2 more sources

Step-Drawdown Test Analysis by Computer

Ground Water, 1975
ABSTRACT Many geohydrologists believe that the step‐drawdown test is useful in determining many important characteristics of a well, whereas others altogether question its utility. In addition to this controversy, its application is hindered because the graphical analysis of data is unwieldy.
Otto J Helweg, John W Labadie
exaly   +2 more sources

A General Solution to the Step-Drawdown Test

Ground Water, 1994
Abstract A more general solution to the step‐drawdown test, called the General Well Function, GWF, is proposed to replace the classic Jacob's step‐drawdown equation for situations when the time that wells are continuously pumped varies greatly. Jacob's equation requires a preselected discharge duration and does not incorporate time as
Otto J Helweg
exaly   +2 more sources

Numerical analysis of step-drawdown tests: Parameter identification and uncertainty

Journal of Hydrology, 2010
An inverse, numerical model is presented as an interpretation method for step-drawdown tests. The model consists of an axi-symmetric model to simulate radial flow in a horizontally stratified aquifer, and a nonlinear regression analysis to identify hydraulic parameters and quantify parameter uncertainty.
L Lebbe, A Vandenbohede
exaly   +2 more sources

Type-Curve Solution of Step-Drawdown Test

Ground Water, 1971
Abstract A set of type‐curves is presented which simplifies and quickens the solution of the Rorabaugh equation for drawdown in a pumping well by eliminating the trial‐and‐error computations. Type‐curve analysis of test data in the field, before pumping is discontinued, provides an indication of the accuracy and adequacy of test data ...
exaly   +2 more sources

Parameter Estimation for Step-Drawdown Tests

Ground Water, 1992
Abstract Step‐drawdown tests may be used to evaluate the well loss component of the well drawdown and to obtain estimates of the aquifer properties. A procedure that analyzes step‐drawdown tests with pumping stages of unequal time durations was formulated and developed into a computer program; the method is applicable to confined ...
exaly   +2 more sources

Well Loss Estimation: Variable Pumping Replacing Step Drawdown Test

Journal of Hydraulic Engineering, 2002
An optimization method is presented for simultaneous estimation of aquifer parameters and well loss parameters utilizing all the drawdowns observed during a variable rate pumping or multiple step pumping test. The proposed method does not require any graphical analysis.
Sushil K Singh
exaly   +2 more sources

Transient analysis of a step-drawdown test using a time-varying well-loss equation

Hydrogeology Journal, 2022
Eunhee lee, Kyoochul Ha
exaly   +2 more sources