Investigating the Impact of Aquifer Long Term Replenishment on the Potomac Aquifer System in Virginia

Groundwater plays a fundamental role in water resource sustainability in Virginia (USA), but overpumping has caused significant declines in the potentiometric surface in the Potomac Aquifer System (PAS). With water levels falling, communities are at risk of wells running dry, saltwater intrusion, and land subsidence. The Sustainable Water Initiative for Tomorrow (SWIFT) project is an aquifer long-term replenishment (ALTR) project that uses continuous recharge into the multi-layered confined aquifer system to restore the potentiometric surface over space and time and increase storage in the system. The SWIFT Research Center (SWIFT-RC) is a 1 million gallon per day (MGD) demonstration facility in Suffolk, Virginia that recharges the PAS through a multi-screen well. Addressing research questions about the impact of continuous, sustained recharge on aquifer systems is crucial to the long-term sustainability of an ALTR project. Quantifying how flow moves through the multi-layered system is necessary to communicate travel times and water quality impacts on the aquifer system. This work uses injectate as an intrinsic tracer, an in-situ flowmeter, and a bromide tracer test to evaluate how flow is distributed through the eleven screens in the recharge well and to assess how flow distribution changes over time. Typically, flow distribution in multi-screen wells is estimated only once over the length of a project and assumed to remain constant for modeling purposes; by measuring flow distribution using multiple methods over the course of the project, this work shows that flow distribution is not constant. In future ALTR projects, developing a consistent and robust monitoring plan to use injectate as an indicator of movement through the aquifer system, paired with other methods to monitor changes in flow distribution, will be a critical part of effectively evaluating how flow moves through the groundwater system.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Civil Engineering

Department dc:contributor.department

Civil and Environmental Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2022

Author dc:creator

• Martinez, Meredith Grace

Chairs dc:contributor.committeechair

• Widdowson, Mark A.
• Bott, Charles B.

Committee members dc:contributor.committeemember

• Strom, Kyle Brent
• Burbey, Thomas J.
• Pruden, Amy

• groundwater
• multi-aquifer
• flowmeter
• tracer test
• indirect potable reuse

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:34280

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/109537