Figure 1. Ground-water resources of Madison County, Ohio (adapted from Ground-Water Resources of Madison County map, M. Hallfrisch, 1994, ODNR Division of Water; illustration prepared by Carlos Lopez).
Michael J. Estadt
A. Wayne Jones
Larry C. Brown
Karen T. Ricker
Water stored under the earth's surface is a plentiful, yet precious, resource in most areas of Ohio. Many human activities may affect the quality and quantity of this resource. However, the availability and quality of this resource are influenced directly by the properties of the geologic formations that hold water. The chemical and physical nature of these formations varies from area to area, creating a wide range of water yields and quality at different depths. This publication contains information about the ground-water resources underlying Madison County. Its purpose is to help the reader better understand the factors that influence the quantity and quality of ground water. An overview of the county's water resources is provided in the publication Water Resources of Madison County, AEX-480.49.
Much of the water-resource and water-quality terminology used in this publication is described in Extension Fact Sheets AEX 460 and 465. Ohio Extension publications are available through the Madison County office of Ohio State University Extension.
Geologic formations (e.g., sand, gravel, limestone, sandstone) have the ability to receive, store, and transmit water. In general, if a formation is capable of yielding enough water to support a well or spring, it is called an aquifer. The material from which the formation was originally made influences its ability to store and transmit water. For example, sand and gravel allow water to flow through easily. By comparison, shale, which originated from compacted layers of mud and clay, generally allows very little water to flow through it unless the shale is highly fractured.
The regionally extensive carbonate aquifer, which is composed of layers of limestone and dolomite, is the principle source of ground water in west-central Ohio, including Madison County. Limestone is consolidated limy mud or calcareous sand, sometimes with fossilized seashells. The main mineral is calcium carbonate, CaCO3. Dolomite is similar to limestone, but has few recognizable fossils; its main mineral is calcium magnesium carbonate, (Ca,Mg)CO3. Limestone and dolomite are technically referred to as carbonate rocks, though they are collectively referred to as limestone. The limestone and dolomite formations which underlie most of western Ohio were deposited about 400 to 450 million years ago. These formations are covered by a layer of glacial till, which is an unsorted mixture of clay, silt, sand, gravel, and boulders deposited by the glacial processes.
Limestone formations are usually good sources of ground water because of their naturally formed solution channels, joints, and fractures, which provide for water storage capacity and pathways for water movement from one area to another. The number of fractures and other openings varies greatly from one location to another and affects the amount of water that may be encountered when drilling a well. The position of such fractures cannot be readily determined from the land surface; therefore there is always some uncertainty as to the production capability of a proposed well.
Another source of ground water in the west-central portion of the county is lenses, (or pockets) of sand and gravel that were deposited by glacial activity. These deposits may be interbedded in the glacial till, or deposited as glacial outwash. Glacial till generally does not provide enough water to support a well.
The yield of a well, in gallons per minute (gpm), will vary considerably depending on the age and depth of the well, the diameter of the casing, well construction, pump capacity and age, and most importantly, properties of the geologic formation. The exact yield and depth of each well will depend on the properties of the geologic formation at the specific location of the well.
To support the development of ground-water availability assessments in Ohio, the Ohio Department of Natural Resources (ODNR), Division of Water, maintains a statewide database of more than 700,000 well logs. The Water Resources Section of the Division manages this valuable database, which includes some information collected by the U.S. Geological Survey (USGS) and the Ohio Environmental Protection Agency (Ohio EPA). Since 1948, well-log information has been collected to increase the understanding of the ground-water resources in Ohio (since the early 1950's, well drillers have been required by State law to file a construction log of each new well). Geologists and hydrogeologists continue to study the state's ground-water resources. As a result, Ohio is one of only a few states that has been completely mapped for ground-water availability (each county has a published, county-specific, ground-water map).
Estimates of the size, shape, geologic make-up, and yields of aquifers have been mapped in Madison County. The map presented in Figure 1 is a generalized representation of the water-bearing formations underlying Madison County (adapted from map by M. Hallfrisch, 1994). This illustration is based on a hydrogeologic interpretation of the well-log data from Madison County and surrounding areas. It should be used only as a guide to understanding the ground-water resources in the county. The section below provides a brief description of the types of aquifers illustrated on the map in Figure 1.
Figure 1. Ground-water resources of Madison County, Ohio (adapted from Ground-Water Resources of Madison County map, M. Hallfrisch, 1994, ODNR Division of Water; illustration prepared by Carlos Lopez).
Area A denotes the dominant source of ground water in the county. This limestone and dolomite aquifer may yield up to 500 gpm at depths typically less than 350 feet. Test wells in northern Darby and Pike townships yielded in excess of 1000 gpm. Domestic and farm wells in this area are developed in sand and gravel lenses and can produce in excess of 100 gpm. These wells are typically 35 to 140 feet deep.
These outwash sand and gravel deposits, illustrated as Area B, underlie the floodplains of many larger streams in the county. Yields of up to 500 gpm are available to properly constructed large-diameter wells.
Figure 2 is a generalized cross section (referenced in Figure 1 as the line X-X') of a portion of Madison County. This cross section illustrates the range of depth to bedrock as well as the variation in composition of the glacial till in Oak Run Township.
Figure 2. Generalized cross section of Madison County, Ohio (adapted from Underground Water Resources map, M-7, ODNR Division of Water; illustration prepared by Kim Wintringham).
Area C denotes the ancestral Teays River Valley and its tributaries. This ancient drainage channel was filled with glacial deposits after the carbonate bedrock channel was eroded. This area may contain several zones of productive sand and gravel deposits yielding up to 500 gpm. Extensive test drilling may be required to locate the most productive deposits.
Area D consists of sand and gravel deposits underlain by the regional carbonate aquifer. Sand and gravel may not be present in the till at all locations, and these deposit areas are variable in thickness of the glacial till over bedrock. Substantial amounts of water may be obtained from properly constructed wells. The carbonate bedrock may yield up to 500 gpm at depths of less than 350 feet.
Illustrated as Area E is the regional carbonate bedrock aquifer overlain with sand and gravel lenses interbedded in the glacial till. Yields of as much as 100 gpm may be obtained from properly constructed large-diameter wells in the carbonate bedrock. Most domestic wells in this area yield 10 to 20 gpm from the sand and gravel at depths of less than 200 feet.
Water bearing sand and gravel deposits interbedded with thick glacial till are illustrated as Area F. Sufficient quantities of water (5 to 25 gpm) for domestic and farm use may be developed. The underlying shale and shaley limestone may yield only meager amounts of water.
The water level in any well does not remain constant, but changes in response to several factors. Rainfall distribution and amount may affect the ground-water recharge and discharge, and subsequently may affect the water level in area wells. Also, wells that are hydraulically connected to a stream may show fluctuations in the water level as the stream level changes. In some cases, depending upon the hydraulic properties of the geologic formation, the intense pumping of a well or number of wells may cause the water level in some nearby wells to be lowered.
The ODNR Division of Water, in cooperation with the USGS, manages a statewide network of water-level observation wells. The network currently consists of 102 State-operated sites equipped with continuous water-level recorders. Water-level data are collected to provide a database for scientists and water resources managers to learn about short- and long-term water-level fluctuations in various aquifers.
The ODNR Division of Water monitors four wells in Madison County located in the London area. Observation Well M-2 is located near the London City well fields, Well M-3 is located north of the Farm Science Review site on SR 38, Well M-4 is located at the London Fish Hatchery, and Well M-5 is located at the London Correctional site. Data on these wells are presented in Table 1.
| Table 1. Characteristics of observation wells in Madison County, Ohio.1 | ||||
|---|---|---|---|---|
| Well No. | M-2 | M-3 | M-4 | M-5 |
| Well Data | ||||
| Well Depth (feet) | 350 | 290 | 49 | 55 |
| Depth to Bedrock (feet) | 173 | 140 | ne2 | ne |
| Water-Bearing Formation3 | LS | LS | SG | SG |
| Land Surface Datum Elevation (feet) | 1035 | 1020 | 1112 | 1090 |
| Continuous Records Since | 8/1971 | 11/19744 | 6/1983 | 10/1986 |
| Historic Water Levels | ||||
| Lowest Water Level5 | 78.6 | 12.0 | 28.6 | 54.6 |
| Month/Year of Occurrence | 11/1994 | 12/1991 | 10/1994 | 1/1992 |
| Highest Water Level6 | +0.55 | 3.9 | +0.5 | 40.5 |
| Month/Year of Occurrence | 4/1980 | 2/1975 | 5/1989 | 4/1989 |
| 1. Data obtained from ODNR Division of Water. | ||||
| 2. Well developed in this formation did not encounter bedrock. | ||||
| 3. LS--Limestone; SS--Sandstone; SH--Shale; SG--Sand and Gravel. | ||||
| 4. Continuous record through 9/1982; periodic thereafter. | ||||
| 5. Water level (in feet) below land surface. | ||||
| 6. Positive sign indicates that water level was actually above ground surface. | ||||
Various state and federal agencies have participated in programs to determine the ground-water quality in Ohio. For nine wells in Madison County, water-quality data were available from the ODNR Division of Water. In Figure 1, these wells are noted as Chemical Analysis Sites 1 through 9. These sites are test wells that were part of a regional ground-water study.
The results from some of the chemical tests performed on these nine Madison County wells are given in Table 2. The chemical constituents listed are total dissolved solids, hardness (as CaCO3), iron, manganese, chloride, sulfate, and fluoride. For comparison purposes, secondary drinking water-quality standards for these chemical constituents also are shown. These standards are established by the U.S. Environmental Protection Agency (USEPA) for public water systems for aesthetic reasons (taste, odor, appearance, etc.), and are not enforceable. These chemical constituents do not pose a risk to human health (see notes in Table 2). For private wells, there are no legally enforceable drinking water-quality standards other than total coliform, which is an indicator of bacteriological quality.
Ground water, whether obtained from bedrock or glacial deposits, may require some treatment. In some areas, water containing calcium carbonate (CaCO3, i.e., hard water), and iron concentrations greater than 0.3 ppm may require treatment for some uses (see notes in Table 2). Wells drilled into shale or limestone may produce water that contains objectionable quantities of hydrogen sulfide gas (rotten egg odor). Hydrogen sulfide concentrations as small as 1 ppm can result in an offensive, rotten egg odor and taste. In general, the probability of obtaining hydrogen sulfide in objectionable amounts increases with the depth drilled.
The information in Table 2 can be used as a guide to what one might expect from an existing or new well developed in similar geologic material in the county. This information provides a general representation of the quality of water at the time of sampling. The data provided in Table 2 were taken from a water sample obtained just after the well was put into operation. Even though eight of these wells were developed in the limestone underlying Madison County, and these wells are in the range of 110 to 387 feet deep, some variation exists in the concentrations of these chemical constituents. Just as well yields differ, water quality will vary depending on aquifer properties at the specific location of each well. One should not forget that many human activities also affect the quality of ground water (see AEX 465).
| Table 2. Chemical constituents of selected Madison County, Ohio, wells.1 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Well No. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | WQ Std2 |
| Well Depth (feet) | 270 | 310 | 387 | 290 | 385 | 56 | 350 | 215 | 58 | |
| Capacity (gpm) | 1500 | 1400 | 200 | 525 | 25 | 9 | 450 | 200 | 15 | |
| Depth to Bedrock(ft) | 23 | 23 | 50 | 140 | 365 | ne3 | 238 | 143 | ne | |
| Water-Bearing Formation4 | LS | LS | LS | LS | LS | SG | LS | LS | SG | |
| Chemical Constituents5 | ||||||||||
| Total Dissolved Solids | 480 | 544 | 743 | 580 | 558 | 461 | 660 | 745 | 506 | 500 |
| Hardness (as CaCO3) | 390 | 450 | 571 | 460 | 377 | 389 | 480 | 512 | 432 | none7 |
| Iron | 1.1 | 0.78 | 0.5 | 1.1 | na6 | 1.6 | na6 | 0.93 | 9.0 | 0.3 |
| Manganese | 0.05 | 0.035 | na6 | 0.11 | 0.03 | 0.12 | na6 | 0.03 | 0.1 | 0.03 |
| Chloride | 4.0 | 1.5 | 14.3 | 6.0 | 36 | 3.0 | 9.5 | 8.0 | 4.0 | 250 |
| Sulfate | 91 | 84 | 245 | 170 | 111 | 91 | 180 | 257 | 80 | 250 |
| Fluoride | 1.7 | 1.7 | na | 1.4 | 0.9 | 1.5 | 69 | 0.6 | 1.6 | 2 |
| 1. Data on these wells taken from map by M. Hallfrisch; General location of each well is shown on Figure 1. | ||||||||||
| 2. USEPA Secondary Water Quality Standard. | ||||||||||
| 3. Well constructed in this formation did not encounter bedrock. | ||||||||||
| 4. LS--Limestone; SG--Sand and Gravel. | ||||||||||
| 5. Units are parts-per-million (ppm); comments as per Interpreting Your Water Test Report (1988); Total Dissolved Solids: Concentrations above 500 ppm may cause adverse taste and deteriorate domestic plumbing and appliances. Use of water containing 500 ppm is common. Hardness: Primary concerns are that more soap is required for effective cleaning, a film may form on fixtures, fabrics may yellow, and scales may form in boilers, water heaters, and cooking utensils. Iron and Manganese: Iron concentrations greater than 0.3 ppm and manganese concentrations greater than 0.03 may cause brown or black stains on laundry, plumbing fixtures and sinks. Metallic taste may be present which may affect the taste of beverages made from the water. Chloride: High concentrations may result in an objectionable, salty taste to water and the corrosion of plumbing in the hot water system. Sulfate: Concentrations in excess of 250 ppm may have laxative effect on persons unaccustomed to the water. Also affects the taste of water and will form a hard scale in boilers and heat exchangers. Fluoride: At concentrations greater than 1.5 ppm, fluorosis (mottling) of teeth may occur. USEPA Primary Standard is 4 ppm. | ||||||||||
| 6. Data not available or constituent not tested. | ||||||||||
| 7. No USEPA Secondary Standard. | ||||||||||
Madison County's ground-water resources are valuable assets to the county's citizens and industry. The availability and quality of these resources are directly influenced by the properties of the geologic formations underlying the county. The productive limestone, and sand and gravel formations that underlie much of Madison County have the potential to provide excellent water adequate for domestic, agricultural, industrial, and many municipal uses. By understanding the physical and chemical nature of these resources, better decisions can be made about ground-water protection, management, and use. This publication provides an overview of the county's ground-water resources. It should be used as a guide, and not as a substitute for detailed information and professional advice when drilling a well.
The Madison County office of Ohio State University Extension can provide other publications about the county's water resources. Your Extension agent, the Madison County Health Department, and Ohio EPA (Central District Office, 3232 Alum Creek Dr., Columbus, OH 43207-3417) can provide information on well-water testing and drinking-water quality. Your local health department and county Extension office also will be able to provide information about proper well construction and requirements for private water systems. For example, State law requires that each new well constructed must be cased to a minimum depth of 25 feet. The health department issues permits and inspects new well construction.
The ODNR Division of Water--Water Resources Section (Fountain Square, Columbus, OH 43224) is an excellent source of information on ground water. Some of the information in this publication was summarized from the map, Ground-Water Resources of Madison County, and other information available through the Division of Water. This map is much more detailed than that given in Figure 1, and the Water Resources Section can provide detailed information on ground-water availability and wells. The Water Resources Section also has conducted a ground-water pollution potential study for the county. This information was published in 1987 (see Bibliography). In regard to constructing a new well, the Division maintains a list of the State's registered and bonded well drillers. Hydrogeologists in the Division may be able to provide you with a list of well drillers who are familiar with geological conditions in your area, and provide technical assistance on proper well construction.
An additional excellent source of Ohio ground-water information is the USGS, Ohio District (975 W. Third Ave., Columbus, OH 43212). The USGS has conducted and published a number of ground- and surface-water investigations in Ohio. Additional information on Ohio's geological formations can also be obtained through the USGS, and through ODNR's Division of Geological Survey.
Ground- and Surface-Water Terminology. 1994. L. C. Brown and L. P. Black. AEX 460. Ohio State University Extension.
Ground-Water Pollution Potential of Madison County Ohio. 1987. ODNR Division of Water.
Ground-Water Resources of Madison County. 1993. M. Hallfrisch, ODNR Division of Water. (map).
Interpreting Your Water Test Report. 1988. D. Lundstrom and S. Fundingsland. AE-937, No. 13-AENG-10. North Dakota State University Extension Service.
Nonpoint Source Pollution: Water Primer. 1996. R. P. Leeds, L. C. Brown and N. L. Watermeier. AEX 465. Ohio State University Extension.
Ohio Ground-Water Quality. USGS National Water Summary--Ohio. 1986. U.S. Geological Survey Water-Supply Paper 2325.
Ohio Ground-Water Resources. USGS National Water Summary--Ohio. 1984. U.S. Geological Survey Water-Supply Paper 2275.
Southwest Ohio Water Plan. 1976. ODNR Division of Water.
The Bedrock Surface and the Distribution of the Consolidated Rocks in Montgomery, Greene, Clark, and Madison Counties, Ohio. 1951. S. E. Norris. Ohio Journal of Science 51(1):13-15.
The Water Resources of Madison County, Ohio. 1959. S. E. Norris. Bulletin 33. ODNR Division of Water.
Underground Water Resources (maps of various river basins). 1958-1962. ODNR Division of Water.
Water-Quality Assessment of Rattlesnake Creek Watershed, Ohio. 1979. K. F. Evans and R. L. Tobin. U.S. Geological Survey Water-Resources Investigations Report 79-17.
Water Resources Data, Ohio, Water Year 1995. Volume 1. Ohio River Basin Excluding Project Data. 1996. U.S. Geological Survey Water-Data Report OH-95-1.
Water Resources of Madison County. 1995. M. J. Estadt, K. T. Ricker and L. C. Brown. AEX-480.49. Ohio State University Extension.
Water Testing. 1988. K. Mancl. AEX 314. Ohio State University Extension.
This publication was produced through the Ohio Water Resources Education Project, in cooperation with: ODNR Division of Water; Ohio EPA; USGS, Ohio District; and Ohio Department of Health (ODH). Project leaders are Larry C. Brown and Karen T. Ricker. Partial support for this publication was provided by these cooperating agencies and programs: Ohio State University Extension, Madison County; Overholt Drainage Education and Research Program; and the Ohio Management Systems Evaluation Area project (USDA CSREES Grant No. 94-EWQI-1-9057).
The project leaders acknowledge the following reviewers: Michael Laughery (USDA NRCS, Madison County); Scott Golden (Environmental Health, ODH); Dave Cashell (ODNR Division of Water); Steve Hindall (USGS, Ohio District); and Mike Bondoc and Linnea Saukko (Ohio EPA, CDO).
A special thanks to Carlos Lopez and Kate Weber (Undergraduate Engineering Assistants) for illustration preparation and Kim Wintringham (Associate Editor, Section of Communications and Technology, Ohio State University Extension) for editorial and graphic production.
All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.
Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.
TDD No. 800-589-8292 (Ohio only) or 614-292-1868