Julie Weatherington-Rice, Ann D. Christy, and Jane L. Forsyth, Bennett and Williams Environmental Consultants Inc., Columbus, OH 43231; Department of Food, Agricultural, and Biological Engineering, The Ohio State University, Columbus, OH 43210; and Department of Geology, Bowling Green State University, Bowling Green, OH 43403

Abstract. This paper describes the importance of subsurface fractures in Ohio glacial tills and provides a historical perspective on fracture research and educational efforts in Ohio. It also serves as an introduction to and overview of this special issue of The Ohio Journal of Science. OHIO J SCI 100 (3/4): 36-38. 2000

Dedication: This special issue is dedicated to the memories of George W. White and Richard P. Goldthwait. They provided the foundation and inspiration for the work that is presented here. And the work continues.

1. What did you find?

We found how water moves through the fine-grained materials that cover our Ohio bedrocks. These mechanisms for movement always existed, and some isolated researchers noted pieces of this process even one hundred years ago. Therefore this is a revisiting, not a completely new discovery. It had been visited before, several times, but no one in a decision-making position had remembered it and it had never become part of the scientific canon of the engineering, hydrogeology and land-use planning fields. What we are looking at are basic physical properties of soils and till, a base level discovery of underlying physical natural properties of the earth (especially in fine-grained glacial tills, lacustrine (lake) deposits and marine clays). Although fractures in rock had long been recognized and even mapped and included in decision making in hydrogeology and petroleum engineering, the environmental professionals and decision makers did not recognize fractures when they occurred in unlithified (not hardened) materials such as glacial tills which overlie the familiar fractured bedrocks. Our research has both expanded the knowledge of these physical properties in the softer materials and, even more importantly, we have looked at the significance of these features.

To give you some background, let us explain that during the last two million years, most of the northern half of the North American continent was repeatedly covered with glaciers. When the glaciers melted, they left deposits (a few inches to hundreds of feet thick) of loose sediments on top of the buried landscapes. Glacially derived deposits cover approximately two-thirds of Ohio. Most of these sediments are fine-grained, consisting of clay, silt, and sand with some gravel and boulders. After the glaciers melted, the land dried out and vertical cracks began to form or expand in the deposits. These cracks were often quite deep, sometimes penetrating through the whole deposit to the buried surface of the bedrock below. On top of these cracked deposits, the soils of most of Ohio and the Midwest formed. At least 95 soil series are known to have formed on fractured materials in Ohio, mostly of ice age origin.

For years, engineers, and many geologists considered these glacial deposits to be slowly or very slowly permeable because as observers, they did not recognize the presence of the fractures or cracks. Laboratory tests on small samples confirmed the assumption that infiltrating rainwater moves very slowly through these materials. However irregularities, such as fractures, are commonly excluded or even purposefully removed from samples submitted for laboratory testing because they are mistakenly thought to have occurred during the sampling procedure.

It was thought that these fine-grained deposits represented excellent places to bury solid and industrial wastes and to locate other potentially contaminating activities. This was the widespread perception and common practice, even though some geologists and soil scientists had long recognized the existence of fractures. In reality, fractures can act as pathways for very rapid water and contaminant flow. These glacial materials that the engineers and geologists thought could not leak, actually do, far faster than we are able to measure with traditional laboratory testing procedures. Consequently, when toxic materials are spilled on the ground or released from an underground sources (e.g., leaking landfills, underground storage tanks, septic systems, livestock lagoons), those toxic materials may be carried rapidly to our underlying ground-water resources. While this rapid transport insures yearly recharge of our ground-water aquifers, it is a critical point of failure when contaminants are moving with that water. Therefore, when we consider installing land uses that could potentially contaminate ground water, we must be certain to site these facilities in areas without prolific aquifers that may be contaminated.

Keep in mind, these fractures provide the recharge water needed to keep Ohio water supply wellfields pumping. So fractures can help us and they can hurt us. But we first need to know where they exist in order to plan our land uses appropriately.

2. What difference does it make that we know this information?

We can now explain anomalous behavior such as rapid travel of contaminants and significant annual recharge of aquifers in fine-grained materials which had been presumed to be very poorly permeable, and therefore could not possibly allow for these observed and documented rapid contaminant break-throughs and well fields with sustainable high yields. We can now explain what we've already been seeing instead of vehemently denying its existence.

3. Who cares?

Those who care include decision makers, governmental agency personnel, and land-use planners who make decisions about water supply planning and environmental cleanups in glacial settings.

4. Who should care?

Everyone who uses ground water as a water supply source, everyone who is responsible for keeping contamination out of ground water and everyone who is concerned with ground water recharge reaching our lakes, rivers and streams (i.e., everyone who works with or relies upon the underground portion of the hydrologic cycle) should care.

5. What are the public (environmental) policy implications of your work? To Ohio? Beyond Ohio?

As we address this question, it is important to keep in mind that we are a group of scientists, engineers and experts in the law. We are primary researchers, not an advocacy group who encourages political decisions based on the research of others. Over the last two decades in Ohio, several of us have helped to develop regional ground-water protection programs to keep our ground water safe and clean in buried valley settings such as the Great Miami River Buried Aquifer. We now understand that we must provide the information needed to develop these same types of policies for our finer-grained areas. These areas with fine-grained glacial materials need to have every new land-use decision evaluated through the mask of fracture flow as an important controlling factor of water and contaminant movement. Society as a whole has to make a commitment to protect, to "do no harm." Our planners need to screen every potential land use to determine if that land use is appropriate in that setting. We all need to set up criteria for areas we choose to protect, critical areas that are currently important aquifers or may become important ground water sources in the future. The first best choice and highest use of our ground water aquifers is water supply, not waste disposal or pollution dilution. We, as a state, must not knowingly create environmental sacrifice zones, especially in the areas where we already have operating public water supply aquifers.

6. Do you expect that any environmental policies or regulations will be changed as a result of this work?

They already have. Over the last ten years, the Ohio Department of Natural Resources (ODNR) has been modifying the state groundwater pollution potential (DRASTIC) maps (uniform statewide ranking of groundwater vulnerability) to include fractures in their rankings. DRASTIC (Aller et al., 1987) internationally used, has been widely adopted by the ODNR Division of Water, and many maps of ground water vulnerability have been developed by that agency on a county by county basis. DRASTIC maps are produced by combining seven input variables. Several of these can be extended or modified to allow DRASTIC to support variable fracture densities. This important information should be used to determine areas where sustainable regional ground water recharge will supply underlying important ground water aquifers. The sustainable recharge for these aquifers will need to be measured accurately if Ohio is going to be able to support significantly increased ground water demands projected for mid-century by ODNR. Conversely, these carefully crafted DRASTIC maps can also be used to identify areas with very limited available ground water supplies, locations where it may be more appropriate to site some of our more potentially contaminating land uses such as landfills.

The first opinion of a legal tribunal in the United States to formally acknowledge the role of fractures in ground-water law was CF/Water et al. v. Schregardus (1998 LEXIS Env. Rep. 12, WL 939721) in which the Ohio Environmental Review Appeals Commission found that the decision to permit a landfill had been made upon an invalid factual foundation, and returned a decision to the Ohio EPA "to conduct an investigation into the application in light of the undisputed presence of fractures in the till overlying the aquifers." The landfill in question was the proposed Clarkco Landfill in Tremont City, Ohio.

7. To what extent will this research contribute to the broad area of environmental science?

We need to rethink our environmental transport models, our ground water remediation techniques, and our land use decisions in light of the existence of fractures. We can no longer blithely assume that our fine-grained granular media assumptions hold in glacial settings.

8. Where do you see the work leading? Next Steps?

Some of the science of our work could lead to (either by us or others) additional research in: geo-biochemical activities along the fractures, additional causes of fractures, and variations of fracture characteristics with various parameters. We find each day that we see new and different directions to take our fracture research. The challenge has been to rein in our collective creative imaginations and try to bite off manageable pieces of the future projects.

We have submitted a proposal to the OARDC Interdisciplinary Team Research Grant program to develop a standardized method for fracture studies, to survey public perceptions of waste disposal and fractures, and to provide the opportunity for ongoing fracture research and environmental education by constructing a permanent soils/ geologic test pit at the OSU Molly Caren Farm in London, Ohio. We propose to design the educational materials for that pit based upon the public perceptions and knowledge gaps identified in the survey.

We are planning to apply for major funding from either NSF or USEPA to establish a fully funded interdisciplinary, multi-institution center for fracture flow studies. This type of a center usually requires a funding level of $1 million or more per year for three to five years. We are currently in conversation with research counterparts at other universities in Ohio, Michigan, Maryland, Tennessee, Iowa, South Dakota, as well as Canada, Denmark and Finland.

We also intend to apply for environmental education funds to support holding workshops at the permanent soils/geologic test pit constructed as part of the OARDC grant, if funded. Researchers will use the results of the public attitudes survey developed under this OARDC grant to help guide the writing of educational materials. Different workshops and conferences will be planned for various audiences: university researchers, environmental professionals and agency personnel, students in K-12 and in higher education, and interested members of the lay public.

How may I order additional copies of this issue?

Single copies of this issue are available ($35, non-members; $20; members). Five or more copies, each ($20, non-members; $10, members). Orders are postpaid from The Ohio Academy of Science, 1500 West Third Ave., Suite 223, Columbus OH 43212-2817. Phone or FAX 614-488-2228. Outside Franklin County Toll Free, if needed, 1-800-OHIOSCIence. Email [oas@iwaynet.net]. Website [http:///www.ohiosci.org].

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This document was written by Julie Weatherington-Rice and Dr. Ann Christy. It was reviewed by Mr. C. Scott Brockman, Mr. Mike Angle , and Dr. Earl Murphy.