Water Well Journal Q&A

GARY M. GIN, RG
The groundwater professional discusses well rehabilitation, aquifer storage and recovery, and critical issues impacting the industry.

By Thad Plumley

Gary M. Gin’s 27 years of experience in the water industry represent diversification.

While he specializes in integrated water resource planning and aquifer storage and recovery (ASR) systems, Gin also focuses on optimizing design and operations for injection wellfields, productions wells, and well rehabilitation projects in his role as a senior technical leader for groundwater infrastructure at Woodard & Curran Inc. in Scottsdale, Arizona.

That’s not even mentioning he has authored two articles for Water Well Journal in the last four years focusing on the diverse subjects of well development and using glass beads as a filter pack.

Gin has more than 8000 hours of operational experience with ASR systems and is an expert at analyzing water infrastructure hydraulics and adopting new technologies and approaches to sustain consistent well performance. He is also a seasoned program manager with a resume of more than 100 projects and a registered geologist in Arizona and Texas.

With such a varied background, WWJ thought midway through the year was the perfect time to catch up with Gin and discuss a variety of topics regarding the groundwater industry.

Water Well Journal: In your new position with Woodard & Curran, you will be working on well rehabilitation among several items. What’s the No. 1 item for a groundwater contractor to know about well rehab?
Gary M. Gin, RG: Collaboration is critical for successful well rehabilitation. All parties including consultants, owners, and contractors must first understand the current state of the well by asking the right questions, such as:

• What is the plumbness and alignment of the well?
• What are the factors that weaken the integrity of the well (root cause)?
• What are the necessary tools, approaches, and chemicals that will be effective in the well’s rehabilitation?
• What is the target concentration and volume of chemicals that need to be applied across the well screen?
• What is the most effective approach in the injection of chemicals into the well screen?
• What mechanical methods can be employed to properly make these chemicals effectively break down clogging agents?
• What indicators demonstrate that the well cleaning procedures
  are effective?

Collaboration must then continue during the rehabilitation phases to quantify what approaches are working and which ones are not. The ability to be agile and modify approaches when necessary has demonstrated increased project successes.

WWJ: You have spent much of your career working with aquifer storage and recovery (ASR) systems. Do you see it continuing to grow in use? Are you feeling busier than ever?
Gin: Across the nation, industries and municipalities are realizing that ASR/injection well systems are a reliable, cost-effective water resource asset for the storage of surface water or injection of advanced purified wastewater. At Woodard & Curran, our systematic and technical approaches and the “state of the science” has reached the point where operations of these systems are proving to be sustainable and reliable long-term. Higher-grade well materials are being selected, and systematic approaches are being implemented to enhance and optimize recharge performance over time.

In fact, directly recharging water from advanced water purification facilities into aquifers is not only one of the most climate-resilient supply options, but it can also be easily scaled based on population and economic activities. The use of ASR/injection well systems are increasing as municipal clients are addressing supply uncertainties and looking to diversify their water resources portfolio and increase resilience through storage and flexibility.

As surface water supplies are diminishing or displaced to other regional watersheds that are disconnected from critical populated basins, replenishment into local groundwater basins will keep those supplies in the basin, reduce overdrafting of aquifers, reduce subsidence rates, reduce saltwater intrusion, and promote the message that subsurface aquifers are a critical infrastructure.

ASR/injection well systems offer other benefits beyond augmenting a supplier’s water resources portfolio, such as:

• Collaboration with power companies to couple energy generation with recharge in ASR well systems
• Waste disposal of brine concentrate via injection wells at desalting wellfield facilities and advanced purification facilities
• Protection of coastal potable aquifers from saltwater intrusion and enhanced coastal aquifer supplies with injection barrier wells
• Significant success for in-situ plume remediation where elevated per- and polyfluoroalkyl substances (PFAS) or solvent exists.

WWJ: What role do you think groundwater contractors have to play in the growing use of ASR? What about their long-term role?
Gin: ASR well systems play a vital role in locally storing water resources for meeting peak demands, mitigating low to moderate supply shortages, sustaining growth, and providing alternative energy solutions. However, because ASR wells tend to clog often, this will require contractors to incorporate new and advanced well maintenance/cleaning services.

Conventional methods such as brushing and bailing are not sufficient. As an industry, we need to recognize that well clogging is deep-seated in the well annulus and at the borehole/aquifer interface. For these clogged ASR wells, a combination of chemical and mechanical methods is typically employed to improve the well’s long-term performance.

Here are questions that should be addressed before employing these advanced well cleaning services:

• What are the clogging agents?
• What chemicals and mechanical methods are available to break down these clogging agents?
• What is the effective volume and strength of the chemicals to be used?
• How are chemicals injected into the well screen?
• What are the mechanical methods that should be employed?
• What is the effective duration these methods should be employed?

WWJ: WWJ completed a three-part series on groundwater and data centers earlier this year. Do you think ASR is an option to control water use at data centers?
Gin: Definitely. Geothermal injection well technologies are being used at an accelerated pace to heat and cool buildings and facilities throughout the United States. Paying attention to the engineering and geochemical details will result in generating an alternative power source coupled with net losses in groundwater resources, which is a win-win especially when conventional means of heating and cooling are becoming more costly.

Injection wells are a critical asset for geothermal pump and injection systems, where there is a steady supply of consistent water temperature resulting in efficient, high-capacity systems per installation capital. In “Data Centers and Groundwater: Part 1” (January 2026 WWJ), pump and injection systems are defined as highly efficient systems.

However, the injection wells require costly maintenance due to the high frequency of well screen clogging and can be challenging to operate. We can take lessons learned from the water industry and transform those solutions into meaningful successes for the geothermal industry.

Additional attention needs to be placed on how to chemically balance the interactions between recharge and groundwater supplies, injection technologies, and strategies on how to optimize recharge operations, including rate and duration.

WWJ: You wrote about glass beads as a filter pack for the August 2025 issue of WWJ. Are you seeing an uptick in their use since that time?
Gin: Absolutely. Wells are costly to site, construct, and operate. Wells are critical assets that need to be highly efficient and be reliable when supply demands are increasing in densely populated areas. Municipalities cannot afford extended periods where wells are not operating and the maintenance required for operations.

We are utilizing higher grade materials to extend the life cycle of these well assets because we can’t afford to replace these wells every 10 to 15 years. I think that article helped explain the hydraulic benefits of glass beads—relationship between permeability and porosity—and that those benefits have been quantified by the other engineers.

Others in the water industry have quantified these hydraulic benefits in glass beads and that the use of glass beads as a filter pack media is not just anecdotal. From a life cycle perspective, wells are costly to drill, construct, and operate. The installation of glass beads as a filter pack media is a small percentage of the total project and operational costs, yet proves long-term pumping efficiencies in operations and during
maintenance.

WWJ: What is the most misunderstood aspect when it comes to the use of glass beads in water well systems?
Gin: Traditionally, filter pack media are designed with a broader gradation to retain most of the aquifer formation from entering the well screen. Glass beads are manufactured with a narrower size gradation than natural sand filter pack media. This narrower glass bead gradation results in a consistent pore diameter, as opposed to a traditional pack that would have pores of varying sizes.

This pore diameter is functionally equal to the maximum grain size of unconsolidated particles that can pass through the filter pack, allowing the well designer to select the maximum size of grains that will be removed from the formation.

To predict the size of sediment grains passing specific-sized pore spaces is a game-changer. Limiting the grain-size particulates that are developed out during backwash events extends the life cycle of pump bowl assemblies and retains consistent well hydraulics.

WWJ: You coauthored an article in the July 2022 issue of WWJ on well development. You noted well development is often the last stage of well construction but is actually among the most
important steps. Can you expand on that?
Gin: For wells drilled with drilling fluid products, standard methods and chemicals used for well development are not sufficient in breaking down these products along the borehole walls.

For newly commissioned ASR wells, insufficient well development could result in severely clogging these wells, pushing these drilling fluid products beyond the borehole annulus, which could lead to significant losses in both recharge duration and rate.

As an industry, we need to explore new well development approaches and utilize the optimal concentrations of chemicals to effectively break down these residual drilling fluids [click here to read article].

WWJ: The article noted the key components to successful well development include the culmination of time, planning, energy, and monitoring. Which one often proves to be the most difficult?
Gin: The emplacement of the chemicals in the well screen, coupled with the mechanical methods employed, are equally difficult to execute. I have been working with drilling contractors for the last eight years and we are making significant progress resulting in efficient water supply wells and ASR wells—more than 90% efficiency.

The collaboration between drilling contractors and consultants has allowed the water industry to devise and refine our well development approaches, and consultants are systematically tracking well development progress (pH, chlorine residual, solids removed, etc.). The collaboration with drilling contractors has yielded great results. It’s a win-win situation for them and the water industry: the industry makes significant improvements, one well at a time, and our clients are gaining confidence in our abilities. Wells are operating at sustained efficiencies over time, which is reducing maintenance costs.

We need to explore new well development approaches and utilize the optimal concentrations of chemicals to effectively break down these residual drilling fluids.

WWJ: Given your time in the industry and your work from all angles (consultant, municipal manager, educator, etc.), what is the single most important factor facing the groundwater industry today and in the near future?
Gin: The transfer of the fundamental knowledge of wells and hydrogeology across contractors, consultants, and municipal managers is in a state of chaos, leaving municipal managers overwhelmed and uncertain of our abilities to be successful.

Often in the water industry, we recommend silver bullet solutions or throw in unnecessary layers of complexities that go against the fundamentals of science, so most municipal managers believe everything we do is in a black box.

Just because the infrastructure is buried underground doesn’t mean hydrogeologists can’t make intelligent decisions. There are newer emerging technologies and approaches that address those uncertainties. The water industry needs to continue to advance technologies, stay rooted in the scientific fundamentals, and broaden our network of experts so that we can better serve clients and communities.

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Thad Plumley is the editor of WWJ and the director of publications for the National Ground Water Association. He can be reached at tplumley@ngwa.org, or (800) 551-7379, ext. 1594.