NDLI: An approach to interpretation of step drawdown tests

Content Provider	Springer Nature Link
Author	Shekhar, Shashank
Copyright Year	2005
Abstract	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 0.03 m/s. Reynold's number (Re) was also calculated to study the nature of flow at the well screen. The decrease in efficiency of the well at higher discharge was attributed to an increase in turbulence and curvature of the flow path of water. An alternative, more efficient approach has been put forward, using a spreadsheet programme to fit a polynomial trend line on a plot of drawdown versus discharge and deriving a polynomial trend line equation. This equation predicts the behaviour of drawdown with discharge under site-specific conditions. The calculated efficiency of the tubewell can, at best, be regarded as a reflection of head loss on account of the laminar flow from the aquifer.Afin de comprendre le comportement du rabattement par rapport au débit d'exhaure dans un contexte spécifique, un pompage d'essai par paliers enchaînés a été effectué dans un forage en contexte alluvial, à proximité de Dehli (Inde); les données ont été analysées dans le but de quantifier l'efficacité du puits. La vitesse d'entrée de l'eau souterraine à travers la crépine a été évaluée pour déterminer si elle excédait la limite de sécurité de 0.03 m/s, et le calcul du nombre de Reynolds a permis d'étudier le régime d'écoulement à travers la crépine. La diminution de l'efficacité du puits pour les plus hauts débits a été attribuée à l'augmentation des turbulences et à la courbature des lignes de courant. Une approche alternative plus efficace a été mise en avant: elle utilise un tableur pour ajuster une courbe de tendance polynomiale sur la représentation graphique rabattement/débit et en tirer une équation caractéristique polynomiale. Cette équation anticipe l'évolution du rabattement avec le débit dans le contexte donné. L'efficacité du forage calculée peut, au mieux, être considérée comme le reflet des pertes de charge liées aux écoulements laminaires depuis l'aquifère.Para entender el comportamiento del descenso con la descarga bajo condiciones específicas del sitio se llevó a cabo una prueba de descenso escalonada en un pozo entubado en aluvión cerca de Delhi, India, y los datos se analizaron para encontrar el valor de la eficiencia del pozo.Se calculó la velocidad de entrada del agua subterránea a la malla del pozo para ver si se excedía el límite de seguridad de 0.03 m/seg y se calculó el número de Reynolds para estudiar la naturaleza del flujo en la malla del pozo.El decremento en eficiencia del pozo a descargas elevadas se atribuyó a un incremento en turbulencia y curvatura de la trayectoria de flujo del agua. Se propone un enfoque alternativo más eficiente usando un programa de hoja electrónica para ajustar una línea de tendencia polinomial en una gráfica de descenso versus descarga y se deriva una ecuación de tendencia de línea polinomial. Esta ecuación predice el comportamiento de descenso versus descarga bajo condiciones específicas del sitio. La eficiencia calculada del pozo entubado puede, cuando mucho, considerarse como un reflejo de la pérdida de presión por el flujo laminar del acuífero.
Starting Page	1018
Ending Page	1027
Page Count	10
File Format	PDF
ISSN	14312174
Journal	Hydrogeology Journal
Volume Number	14
Issue Number	6
e-ISSN	14350157
Language	English
Publisher	Springer-Verlag
Publisher Date	2006-02-04
Publisher Institution	International Association of Hydrogeologists
Publisher Place	Berlin, Heidelberg
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Step drawdown test Well efficiency Entrance velocity Trend line Tubewell design Waste Water Technology Water Pollution Control Water Management Aquatic Pollution Geology Hydrogeology
Content Type	Text
Resource Type	Article
Subject	Earth and Planetary Sciences Water Science and Technology

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

Erratum to: An approach to interpretation of step drawdown tests

Identification of aquifer and well parameters from step-drawdown tests

Understanding diagnostic plots for well-test interpretation

Interpretation of single-well tracer tests using fractional-flow dimensions. Part 1: Theory and mathematical models

Interpretation of single-well tracer tests using fractional-flow dimensions. Part 2: A case study

Review: Hydraulics of water wells—flow laws and influence of geometry

Hydrogeology of deep-well disposal of liquid wastes in southwestern Florida, USA

Water-Well Siting in Hard-Rock Areas: Identifying Promising Targets Using a Probabilistic Approach

Editor’s message

An approach to interpretation of step drawdown tests

Similar Documents

Erratum to: An approach to interpretation of step drawdown tests

Identification of aquifer and well parameters from step-drawdown tests

Understanding diagnostic plots for well-test interpretation

Interpretation of single-well tracer tests using fractional-flow dimensions. Part 1: Theory and mathematical models

Interpretation of single-well tracer tests using fractional-flow dimensions. Part 2: A case study

Review: Hydraulics of water wells—flow laws and influence of geometry

Hydrogeology of deep-well disposal of liquid wastes in southwestern Florida, USA

Water-Well Siting in Hard-Rock Areas: Identifying Promising Targets Using a Probabilistic Approach

Editor’s message

An approach to interpretation of step drawdown tests