Sourcing groundwater contamination from possible mine drainage in Navarre, Ohio using MODFLOW

May 1, 2020   /  

Student: Alexis Lanier
Major: Geology
Minor: Ancient Mediterranean Studies
Advisor: Dr. Karen Alley

Alexis LanierThis study examines an abandoned underground coal mine in Navarre, Ohio to determine if it is the source of nearby groundwater contamination. Sourcing contamination is important to improve efficiency of remediation efforts. Samples were taken from domestic wells surrounding the mine and analyzed geochemically. Two wells were found to have significant contamination, consistent with that typically found in areas affected by mine drainage. MODFLOW, a groundwater modeling software, was used to characterize flow in the area and backward-track contamination at each sample well. Two wells, the same found to have significant contamination, tracked flow back to the mine of interest, while all others tracked flow elsewhere. Geochemical analysis and modeling together provide significant evidence that contamination from the two affected wells originates in the mine and can be considered mine drainage. However, consistent use of terms associated with mine drainage is necessary to protect affected areas.

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Global clean water supply is heavily dependent upon groundwater. Making up about 99% of Earth’s total liquid freshwater, groundwater is not only plentiful, it is also resilient to contamination. Most pollution must infiltrate into the ground to reach aquifers, passing through naturally occurring sediment filters. However, contamination from underground mines can seep directly into groundwater supplies, bypassing the usual mechanisms of infiltration and recharge. As a result, contamination from mines, commonly called acid mine drainage (AMD) or mine drainage, is a major concern in areas where drinking water is obtained from groundwater near mines. My study sought to find a methodology for identifying and sourcing contamination from abandoned underground mines, motivated by the need to protect and sustainably manage groundwater supplies. Continual contamination of water supplies slowly depletes water available for human use, so sourcing contamination is essential for its effective remediation.

I decided to focus my research on contamination in my hometown of Navarre, Ohio. Underground coal mines are common in the area, but are they the cause of groundwater contamination here? I chose a mine to examine, Fox 12, and took well samples from several houses surrounding the mine to be geochemically analyzed. I found that two wells in particular seemed to have higher contamination relative to the rest of the sample wells, and this contamination was consistent with mine drainage. To see if the contamination could be attributed to the mine, I created a groundwater flow model of the area using MODFLOW, a groundwater modeling software. This allowed me to backward-track contamination from each well to its source. Two wells, the same two found to be geochemically more contaminated than the rest, traced flow through the mine of interest. Observed trends in geochemistry and results from modeling agreed, placing the source of contamination for these wells in the study mine.

The specific results of my study conclude that mine drainage is present in Navarre, but not at concerning levels. On a wider scale, these results provide a framework for detecting and sourcing contamination from mine drainage, demonstrating it to be effective for areas with complex hydrogeological conditions. To ensure safe and consistent use of groundwater for human consumption as well as preserve natural freshwater ecosystems, we must protect aquifers from existing contamination, fixing the mistakes of the past to ensure the sustainable and responsible use of groundwater for the future.

Alexis will be online to field comments on May 8:
2-4pm EDT (PST 11am-1pm, Africa/Europe: evening)

54 thoughts on “Sourcing groundwater contamination from possible mine drainage in Navarre, Ohio using MODFLOW”

  1. Alexis, this is a very interesting study. I am interested to know the town’s reaction to your work. Did you share your findings with the town and how did they react?

    1. Dr. Florence, thank you! I have not yet given my findings to any specific town entity, but I got an idea of reactions when I requested to sample wells near the mine. People were generally curious, but not terribly concerned. Some seemed not to completely trust me, which was a little surprising. They were eager to share their own stories of mining and “strange water”, but most did not seem concerned about their own water.

      1. How interesting! Alexis, this is a very impressive project. Congratulations on your excellent work and best of luck in graduate school. You will be missed!

  2. Very well done, Alexis! Crisp, accessible writing and a fascinating scientific adventure. We’re very proud of you in your department!

    1. Thank you, Dr. Wilson! I couldn’t have done it without you all.

  3. Alexis,

    My parents live in Navarre so your study hits home for me. Thank you for focusing on this important topic and for clearly articulating your results.

    Congratulations and we look forward to welcoming you and your class to the alumni community!

    Meret Nahas ’10

    1. Meret! It’s just your old advisor saying hello. Hope all is well. Thanks for participating here!

      Mark A. Wilson

      1. Hi, Dr. Wilson, Lauren Vargo’s mom here. Exciting to see that you are sending another talented young woman into the field. Best wishes to all in the Geology Department.

        1. Thanks, Bambi! Give our best to Lauren — she’s one of our heroes!


    2. Meret,
      Thanks for your interest! It’s good to hear from someone else who knows the area. Have you seen or experienced anything to indicate mine drainage near your parents’ house?
      I’m excited to join such a distinguished community!

  4. Hi Alexis! Well done! Your research shows the power of looking at a problem from different perspectives – geochemical and hydrological. If you had only used one method, would you have come up with the same interpretation?

    1. Thank you, Dr. Pollock! If I had only used one method, I believe I would have come to the same general conclusion, but I would have had much less confidence in my results. The agreement present between the two methods provides validity to each. Each method serves as a check for the other, which is especially helpful when evaluating bias.

  5. Congratulations! This is such an important area of study and you’ve done a great job explaining its significance and the practical use of your methodology for finding contamination.

    1. Thanks, Emma! It’s great to hear from you! I’m glad to hear that; one of my major goals for the study was to have that practical component, to hopefully make a difference.

  6. Great job Alexis! Your topic is super important and I can’t wait to see how you continue this research in the future!

    1. Thank you, Emily! I hope I’ll be able to expand on some of this type of work in graduate school.

  7. This is super cool!

    Do you think there will be any long term reactions to your project? How about the methods you used?

    Good luck with next year and Congrats!

    1. Thanks, Brendan! I don’t think my project will cause any ripples through the community, but perhaps it can better inform future residents of possible concerns with their water. I believe my results have validated my methods to some degree, proving them useful in identifying contamination from abandoned underground mines. Hopefully, with this validation, these methods will be useful for future studies examining contamination in areas with a complex hydrogeology.

  8. Alexis, well done! I’ve always admired you, and I look forward to seeing what you get up to in the future.

    1. Thank you for the kind words, Henry! The admiration is mutual, and I’m excited to see what your bright future holds as well.

  9. Alexis, nice project, and so interesting to do a project close to home. I am curious as to whether your finding that elevated acidity does not correlate with presence of metals is novel, or whether that was already generally known.

    1. Thank you, Karen! It’s an unusual finding, as most occurrences of mine drainage are both highly acidic and metalliferous, but it’s not entirely novel. The effect of limestone dissolution on the pH of my samples plays an instrumental role in this relationship, and could be obscuring the correlation typically seen. Plumlee et al.’s “Geologic Controls on the Composition of Natural Waters and Mine Waters Draining Diverse Mineral-Deposit Types” (1999) does a great job of explaining this relationship, finding that acidity and metal content is generally correlated, but that low acidity does not preclude the presence of metals. However, to my knowledge, my study is novel in that it looks specifically at this relationship between groundwater and abandoned underground mines, as well as that it uses a combination of geochemical analysis and modeling to do it. The small sample size of my study is a significant limitation, though, and future work would improve this.

      1. Hey Alexis. To complete the circle, Karen Havholm was one of my fantastic teaching assistants when I was a geology students. And you, of course, were one of my very best TAs ever in my geology teaching. Cosmic!

  10. Great work, Alexis! I am curious: What techniques did you use to analyze the groundwater samples?

    1. Thank you, Dr. Faust! I sent my samples to STAR Lab at the OARDC, where they did a sulfate anion analysis through ion chromatography and a mineral analysis to determine the complete suite of elemental concentrations through inductively coupled plasma spectroscopy. To analyze the results, I ran several Spearman’s rho correlation tests, plotted my results on a Ficklin diagram (to compare my samples with other typical mine drainage compositions), calculated an acid mine drainage index for each sample (Gray, 1996), and classified the samples based on published methods from the ODNR (Calhoun and Kinney, 2016).

  11. Hey from across the kitchen table! Even though I’ve heard a lot about your project, I don’t know much about your experiences with MODFLOW. What are some of the software’s strengths/weaknesses?

    P.S. I’m so super very incredibly extremely profoundly proud of you!

    1. Hello from the other side of the table, Cara! The software is extremely flexible and versatile, which is part of what makes it so popular. There are a lot of derivative programs, using the base of MODFLOW to modify it for a more specific purpose. It’s also freely available from the USGS, so anyone can use it. However, it is command-line based, which means you either have to have some coding background to use it or you have to use a graphical user interface with it. It has a bit of a steep learning curve, with many nuances and variables. It’s an excellent program, so I would highly recommend it, but I would also recommend finding a good graphical user interface with help support as well as some experienced colleagues to contact if you run into troubles.

  12. What a wonderful project this is! I also enjoyed hearing some of the stories that our neighbors had! Nice poster to summarize it all up! You should be so proud! Words cannot begin to describe how proud we are of you😘

  13. Hi, Alexis, I am the mom of Lauren Vargo, ’13 COW grad from the Department of Geology. Wiles was her advisor, too. It is wonderful to see research with such a practical and local application. I had no idea that underground coal mines were just outside of Wooster. When were the mines “abandoned?” Had there been any issues/concerns with mine drainage in the past? I noticed your comment about people mentioning funny tasting water. I got the impression that you researched drainage from one specific mine. Can it be assumed then that drainage from other mines in the area are not a concern, also? Congratulations on a job well done! Best wishes!

    1. Hello Bambi! It’s great to hear from the parent of a fellow grad! Thank you for your interest. Yes, there are a lot of abandoned underground coal mines all over eastern Ohio. You are correct, I looked at contamination from one mine, Fox 12, which shut down in 1915. Many in the area are concerned about contamination, and so do not drink the water that comes from their well, instead opting to buy bottled water. As you walk down the road near the mine, orange iron particles are visible in the ditch. The water sometimes smells like sulfur, running orange at times. It cannot be assumed based on my results that contamination from other mines is not also a concern, as each mine is unique and the hydrogeology of the area is extremely variable, but it does provide some evidence that the limestone of the area does mitigate some possible contamination. Thanks again for your comment!

  14. Excellent work, Alexis! This is a really cool project.

    Are the mines literally underneath Navarre, or are they in the surrounding areas? If the latter, do they affect agriculture in the area?

    Also, I remember us having a conversation during AMRE 2 years ago about how I had never been to Navarre. I want to let you know that I did ride my bicycle through Navarre last year.

    1. Thank you, Dr. Fox! Some of the mines do lie directly underneath Navarre, but most are in areas on the outskirts of the town itself. These are near some of the farms, but the mines are so far down (my study mine was about 300 feet below the surface) that I don’t believe they would have any effect on agriculture. However, the drainage may affect nutrient availability in some areas.
      I remember that conversation as well, and I’m glad to hear it. Thanks for your interest!

  15. Hi Alexis. I am so proud of you in all of your accomplishments. I do not understand all of your work but I know it is very important and you have done a wonderful job. Love you!

  16. Hi, Alexis, does your research assist in resolving the drinking water issues at your house? I could tell talking with you over the past four years that the geology department at COW and the professors there were a great fit for you.

    1. Hello grandpa! My research doesn’t necessarily assist here, as the town does not have the resources to remediate, nor is the contamination severe enough to warrant additional resources. However, if remediation were to become a viable option in the future, I believe my research would be a good starting point for figuring out how to do it. A larger sample size would be beneficial, both in terms of samples and interpolation wells to characterize the geologic layers, however. They were an excellent fit for me, and I’m happy to have chosen to spend my time at Wooster! Thank you!

  17. Interesting work. Are the 2 wells in question have a linkage that can be tied to geographic proximity, well depth, presence of a certain formation, etc… that might illuminate where one could look next for contamination?

    1. Hello JD, thank you for your interest. The two wells do not have a similar depth, nor are they in a specific formation. However, they are the two closest wells to my study mine that are hydrologically downstream based on the potentiometric surface, which can tell us about how groundwater flows. Based on my results, I’d say that we should look for contamination at downstream wells that are geographically closest to the mines. This could be due to the presence of limestone in the study area; the further the water travels through the host rock, the more limestone it comes into contact with, and the more contamination is drawn out of the water. Thanks for the question!

  18. Hi Alexis! Great work! I am sorry we never had the chance to chat over coffee – maybe over the summer sometime.

    If you would not have collected these samples and done this research for this study, would any type of regular testing have been able to show similar results or be the reason for suggesting further study? I guess what I am asking is, can the community trust that possible contamination is being monitored regularly?

    1. Hello Stephanie! Thank you, and I’d be happy to chat sometime over the summer, as long as the pandemic eases up soon. Part of the concern regarding my study is that the area I examined lies primarily outside of the town proper, and the wells are largely privately-owned. So, testing is generally only done if the individual homeowners organize and finance it. At private wells like these, usually this is not the case and water is not regularly monitored, so if any changes in the system were to occur and contamination made worse, the residents may not have a way to know about it. That’s a main part of the motivation for my study; I sent the results of testing to each homeowner to make them aware of what’s in their water. However, public water suppliers, like those the town of Navarre or Wooster uses (“city” or “tap” water), are required to annually monitor their water and publish yearly findings called Consumer Confidence Reports (CCRs). Thanks again for your interest!

      1. Makes perfect sense! Thank you for clarifying, and thank you for your care and attention to your hometown. Best of luck to you after graduation!

        1. Thank you! Let me know if you have any other questions. Thanks again, best of luck in your future endeavors as well!

  19. Hi Alexis,

    Great job on the study – I particularly like the idea that one of the conclusions is that it’s tough to know what to call contaminated in setting where the natural waters are loaded with chemicals from the surrounding geology. Nice work and best wishes is the great Hydrogeology program as MSU.

    1. Hello Dr. Wiles,
      Thank you! I greatly appreciate all of your help with the project. It’s easy to call something contaminated or not, but in reality, everything lies on a spectrum. Where do we draw the line? That’s something I wanted to dig into with my study. Thanks again, I’m looking forward to beginning work with MSU!

    2. Hi, Dr. Wiles, Lauren Vargo’s mom, Bambi, here. Congratulations on mentoring another talented young woman geologist! Best wishes.

  20. Hi Alexis–

    So proud of you for doing a virtual presentation at IS Symposium. And, to top it off, you used MODFLOW!! Wow. That’s definitely not an easy program to use, but your experience using it on your IS will put you one step ahead of the game as you enter grad school. Also, I was really excited to see you do some research near Navarre. IS research in Ohio is a great thing, because it helps add to the geologic knowledge-base of our broader community.

    Again, great job finishing IS, doing this Symposium, and for finishing finals this week. -SJ

    1. Hello Dr. Judge,
      Thank you so much for all of your support! It was challenging, but enjoyable to learn how to navigate the intricacies of MODFLOW. I think it will definitely be worth the effort. Working to learn about where you live and work is important, so I’m glad to have gotten the opportunity to expand our knowledge of the area. Thanks again for everything!

  21. Fantastic! I would be interested to see about our city water, as sometimes I can smell and even taste the chlorine in it!

    1. Thanks, Aunt Heather! I’d be interested to see, too. There should be a Consumer Confidence Report (CCR) on your city water, which details annual testing results. It’s an important thing to look into. Thanks for the comment!

  22. Hey there! Your project is very detailed and precise ! Proud of you and all of the hard work you have done to accomplish something as meaningful as this. Maybe you could present your findings at a town hall meeting? Just the first steps in your amazing future! Proud of you !!

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