Effects of Intraborehole Flow on Purging and Sampling Long-Screened or Open Wells

David L. Poulsen, Peter G. Cook, Craig T. Simmons, James L. McCallum, Shawan Dogramaci

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Hydraulic head differences across the screened or open interval of a well significantly influence the sampled water mixture. Sample bias can occur due to an insufficient pumping rate and/or due to native groundwater displacement by intraborehole flow (IBF). Proper understanding of the sampled water mixture is crucial for accurate interpretation of environmental tracers and groundwater chemistry data, and hence groundwater characterization. This paper uses numerical modeling to quantify sample bias caused by IBF in an un-pumped high-yield well, and the influence of pumping rate and heterogeneity on the volume of pumpage required to purge an IBF plume. The results show that (1) the pumping rate must be at least an order of magnitude greater than the IBF rate to achieve permeability-weighted yield, (2) purge volume was 2.2 to 20.6 times larger than the IBF plume volume, with the ratio depending on plume location relative to hydraulic conductivity and head distributions, and (3) after an example 1000-day un-pumped period, purging required removal of at least three orders of magnitude more water than the common practice of three to five well volumes. These results highlight the importance of knowing the borehole flow regime to identify IBF inflow and outflow zones, estimate IBF rates, and to develop a strategic sampling approach.

Original languageEnglish
Pages (from-to)269-278
Number of pages10
JournalGroundwater
Volume57
Issue number2
DOIs
Publication statusPublished - 1 Mar 2019
Externally publishedYes

Fingerprint

Purging
Groundwater
Sampling
well
sampling
Flow rate
Water
Hydraulic conductivity
Boreholes
pumping
plume
hydraulic head
Hydraulics
groundwater
effect
water
hydraulic conductivity
inflow
outflow
borehole

Cite this

Poulsen, David L. ; Cook, Peter G. ; Simmons, Craig T. ; McCallum, James L. ; Dogramaci, Shawan. / Effects of Intraborehole Flow on Purging and Sampling Long-Screened or Open Wells. In: Groundwater. 2019 ; Vol. 57, No. 2. pp. 269-278.
@article{26c2f61699b7482c831cccbd44150126,
title = "Effects of Intraborehole Flow on Purging and Sampling Long-Screened or Open Wells",
abstract = "Hydraulic head differences across the screened or open interval of a well significantly influence the sampled water mixture. Sample bias can occur due to an insufficient pumping rate and/or due to native groundwater displacement by intraborehole flow (IBF). Proper understanding of the sampled water mixture is crucial for accurate interpretation of environmental tracers and groundwater chemistry data, and hence groundwater characterization. This paper uses numerical modeling to quantify sample bias caused by IBF in an un-pumped high-yield well, and the influence of pumping rate and heterogeneity on the volume of pumpage required to purge an IBF plume. The results show that (1) the pumping rate must be at least an order of magnitude greater than the IBF rate to achieve permeability-weighted yield, (2) purge volume was 2.2 to 20.6 times larger than the IBF plume volume, with the ratio depending on plume location relative to hydraulic conductivity and head distributions, and (3) after an example 1000-day un-pumped period, purging required removal of at least three orders of magnitude more water than the common practice of three to five well volumes. These results highlight the importance of knowing the borehole flow regime to identify IBF inflow and outflow zones, estimate IBF rates, and to develop a strategic sampling approach.",
author = "Poulsen, {David L.} and Cook, {Peter G.} and Simmons, {Craig T.} and McCallum, {James L.} and Shawan Dogramaci",
year = "2019",
month = "3",
day = "1",
doi = "10.1111/gwat.12797",
language = "English",
volume = "57",
pages = "269--278",
journal = "Groundwater",
issn = "0017-467X",
publisher = "Wiley-Blackwell",
number = "2",

}

Effects of Intraborehole Flow on Purging and Sampling Long-Screened or Open Wells. / Poulsen, David L.; Cook, Peter G.; Simmons, Craig T.; McCallum, James L.; Dogramaci, Shawan.

In: Groundwater, Vol. 57, No. 2, 01.03.2019, p. 269-278.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effects of Intraborehole Flow on Purging and Sampling Long-Screened or Open Wells

AU - Poulsen, David L.

AU - Cook, Peter G.

AU - Simmons, Craig T.

AU - McCallum, James L.

AU - Dogramaci, Shawan

PY - 2019/3/1

Y1 - 2019/3/1

N2 - Hydraulic head differences across the screened or open interval of a well significantly influence the sampled water mixture. Sample bias can occur due to an insufficient pumping rate and/or due to native groundwater displacement by intraborehole flow (IBF). Proper understanding of the sampled water mixture is crucial for accurate interpretation of environmental tracers and groundwater chemistry data, and hence groundwater characterization. This paper uses numerical modeling to quantify sample bias caused by IBF in an un-pumped high-yield well, and the influence of pumping rate and heterogeneity on the volume of pumpage required to purge an IBF plume. The results show that (1) the pumping rate must be at least an order of magnitude greater than the IBF rate to achieve permeability-weighted yield, (2) purge volume was 2.2 to 20.6 times larger than the IBF plume volume, with the ratio depending on plume location relative to hydraulic conductivity and head distributions, and (3) after an example 1000-day un-pumped period, purging required removal of at least three orders of magnitude more water than the common practice of three to five well volumes. These results highlight the importance of knowing the borehole flow regime to identify IBF inflow and outflow zones, estimate IBF rates, and to develop a strategic sampling approach.

AB - Hydraulic head differences across the screened or open interval of a well significantly influence the sampled water mixture. Sample bias can occur due to an insufficient pumping rate and/or due to native groundwater displacement by intraborehole flow (IBF). Proper understanding of the sampled water mixture is crucial for accurate interpretation of environmental tracers and groundwater chemistry data, and hence groundwater characterization. This paper uses numerical modeling to quantify sample bias caused by IBF in an un-pumped high-yield well, and the influence of pumping rate and heterogeneity on the volume of pumpage required to purge an IBF plume. The results show that (1) the pumping rate must be at least an order of magnitude greater than the IBF rate to achieve permeability-weighted yield, (2) purge volume was 2.2 to 20.6 times larger than the IBF plume volume, with the ratio depending on plume location relative to hydraulic conductivity and head distributions, and (3) after an example 1000-day un-pumped period, purging required removal of at least three orders of magnitude more water than the common practice of three to five well volumes. These results highlight the importance of knowing the borehole flow regime to identify IBF inflow and outflow zones, estimate IBF rates, and to develop a strategic sampling approach.

UR - http://www.scopus.com/inward/record.url?scp=85057504355&partnerID=8YFLogxK

U2 - 10.1111/gwat.12797

DO - 10.1111/gwat.12797

M3 - Article

VL - 57

SP - 269

EP - 278

JO - Groundwater

JF - Groundwater

SN - 0017-467X

IS - 2

ER -