Figure 1. Ground-water resources of Ross County, Ohio (adapted from Ground-Water Resources of Ross County map, J.J. Schmidt, ODNR Division of Water; illustration prepared by Carlos Lopez).
Ray Wells
James M. Raab
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 and formations. This publication contains information about the ground-water resources underlying Ross 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 Ross County, AEX-480.71.
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 Ross County office of Ohio State University Extension (614-775-3200).
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 originally was 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 major source of ground water in south-central Ohio, and Ross County, is the unconsolidated aquifer composed of coarse-grained sand and gravel. This highly permeable aquifer is found in the Scioto River valley, as well as portions of the Deer Creek, Paint Creek, and North Fork Paint Creek valleys. These types of aquifers form as the result of glacial outwash. Under much of the Scioto River is a buried valley aquifer, so-called because it resulted from the filling of the pre-glacial Teays River valley. This aquifer provides some of the state's most abundant ground-water supplies.
Other sources of ground water are the lenses (or pockets) of sand and gravel that are interbedded in the glacial deposits of clay, silt, and fine sand. This type of aquifer is found in the glaciated northern and western portions of Ross County and in the drainage channels of some smaller streams in other parts of the county.
Limestone formations that occur below the glacial till are a major source of ground water in the far southwestern portion of Ross County, within the Paint Creek watershed. Limestone formations usually are adequate sources of ground water because of their naturally formed solution channels, joints, and fractures, which provide water storage capacity and pathways for water movement.
Shale and shaley sandstone bedrock aquifers are located in the eastern and southern portions of Ross County. These aquifers yield very limited supplies of ground water because of their impervious nature.
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 for Ross County. The map presented in Figure 1 is a generalized representation of the water-bearing formations underlying Ross County (adapted from map by J. J. Schmidt, 1980). This illustration is based on a hydrogeologic interpretation of the well-log data from Ross 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 Ross County, Ohio (adapted from Ground-Water Resources of Ross County map, J.J. Schmidt, ODNR Division of Water; illustration prepared by Carlos Lopez).
A large unconsolidated aquifer, illustrated in Figure 1 as Area A, is comprised of permeable sand and gravel, with thin layers of clay and silt, which were deposited by glacial meltwater. Located in areas adjacent to the Scioto River, wells in this aquifer yield in excess of 1000 gpm. These high yielding wells range from 85 to 125 feet in depth, and induce recharge by river infiltration.
Figure 2 is a generalized cross section (referenced in Figure 1 as the line X-X') of a portion of Ross County. This cross section, which dissects the Scioto River, Lick Run, Dry Run, Little Walnut Creek, and Walnut Creek valleys, illustrates the range of depth to bedrock as well as the variation in composition of the glacial materials. This cross-section clearly shows the large buried valley aquifer of highly permeable sand and gravel that underlies the Scioto River valley in this area.
Figure 2. Generalized cross section of Ross County, near Chillicothe, Ohio
(adapted from Underground Water Resources map M-11, ODNR Division of
Water, illustration prepared by Kim Wintringham.)
Area B is also characterized by thick, permeable deposits of sand and gravel similar to those of Area A. However, these deposits are beyond the recharge influence of the Scioto River. Wells in this area yield from 100 to 500 gpm. Test drilling may be required to locate the coarser deposits.
Permeable deposits of sand and gravel beneath areas adjacent to Paint Creek, Deer Creek, and North Fork Paint Creek are denoted as Area C. Properly constructed wells yielding from 100 to 500 gpm range in depth from 55 to 85 feet. The higher yielding wells are located in areas recharged by stream infiltration.
Area D contains thin to thick lenses of permeable sand and gravel interbedded in thick layers of clay. Located in the valleys of Paint Creek and North Fork Paint Creek, wells that yield 25 to 75 gpm can be developed at depths of 30 to more than 150 feet. Test wells are often necessary to locate the isolated coarse water-bearing deposits.
Relatively thick clay deposits with water-bearing lenses of sand and gravel make up this upland area in the northern portions of Ross County. Wells in Area E that yield 10 to 25 gpm can be developed at depths of as much as 110 feet. If water-bearing deposits cannot be found, the limestone bedrock in areas west of the Scioto River can be developed from wells up to 200 feet in depth.
Area F illustrates shallow unconsolidated deposits of clay with thin lenses of sand and gravel overlying limestone bedrock in the Paint Creek valley. Yields satisfactory for domestic use can usually be developed at depths of less than 120 feet. These wells may yield 10 to 25 gpm.
Thick deposits of clay, silt, and fine sand with thin layers of sand and gravel partially filling the pre-glacial Teays River drainage channel are denoted as Area G. From these deposits located in the southeastern corner of the county, wells may yield 10 to 25 gpm. If permeable deposits are not encountered, deeper drilling into the non-water bearing shale is not recommended.
Area 4-H is made up of thick glacial deposits of silt and clay interbedded with thin lenses of sand and gravel. Wells developed in the sand and gravel lenses yield 3 to 10 gpm at depths of up to 250 feet. West of the Scioto River, some wells are drilled into the limestone bedrock at depths of 250 feet or more, and produce similar water yields.
Thin glacial deposits, illustrated as Area I, contain a limited amount of permeable sand and gravel. These deposits are found in narrow stream channels that cut between shale ridges. Wells drilled into these deposits generally yield less than 5 gpm at depths of 50 to 165 feet.
Very limited supplies of ground water can be obtained from thin clay deposits and the underlying shale and shaley sandstone bedrock denoted as Area J. This area makes up a large portion of Ross County. Most of this area is unglaciated, or has only thin glacial deposits over the ridge tops. Wells drilled into the shale generally yield less than one gpm. Dug wells, ponds, and cisterns are also used as water sources in areas not served by the Ross County Water Company, which serves portions of five counties.
The water level in any well usually does not remain constant, but may change depending on several factors. Rainfall distribution and amount may affect 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 on 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 ground-water levels in two wells in Ross County. These wells, noted as Observation Wells RO-7 and RO-8 in Figure 1, are located near Bainbridge and Chillicothe, respectively. Observation Well RO-7 is 67 feet deep and RO-8 is 95 feet deep. Both wells were constructed in sand and gravel deposits. Continuous water-level measurements have been recorded at Observation Well RO-7 since February 1971, and at RO-8 since May 1983. The lowest level recorded on Observation Well RO-7 at Bainbridge was 45.9 feet below land surface in December 1989 (previous record low of 45.8 in July 1988); the highest level recorded was 20.9 feet below land surface in February 1971. The lowest level recorded on Observation Well RO-8 in Chillicothe was 32.6 feet below land surface in December 1988; the highest level recorded was 18.9 feet below land surface in May 1995.
Various state and federal agencies have participated in programs to determine the ground-water quality in Ohio. For six wells in Ross County, water-quality data were available from the ODNR Division of Water, and the Ohio EPA Division of Drinking and Ground Water. In addition, information on a seventh well is included from Pickaway County, located just north of Clarksburg. In Figure 1, the six Ross County wells are noted as Chemical Analysis Sites 1 through 6. These sites are municipal wells.
The results from some of the chemical tests performed on these Ross County wells are given in Table 1. The chemical constituents listed are total dissolved solids, hardness (as CaCO3), iron, and chloride. 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 1). 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 and manganese concentrations greater than 0.3 and 0.03 ppm, respectively, may require treatment for some uses (see notes in Table 1). 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 sulfur in objectionable amounts increases with the depth drilled.
The information in Table 1 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 water quality at the time of sampling, which was not the same for all wells. In most cases, the data provided in Table 1 were taken from a water sample obtained just after the well was put into operation. Even though four of these wells were developed in the permeable sand and gravel underlying Ross County, and these wells are in the range of 72 to 100 feet deep, some variation exists in the concentrations of each 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 1. Chemical constituents of selected Ross County, Ohio, wells.1 | ||||||||
|---|---|---|---|---|---|---|---|---|
| Well No. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | WQ Std2 |
| Well Depth (feet) | 69 | 100 | 76 | 89 | 80 | 85 | 250 | |
| Capacity (gpm) | 75 | 500 | 100 | 400 | 12 | 2400 | 10 | |
| Depth to Bedrock (feet) | ne3 | ne | 72 | ne | ne | 85 | 169 | |
| Water-Bearing Formation4 | SG | SG | G, LS | SG | SG | SG | LS | |
| Chemical Constituents5 | ||||||||
| Total Dissolved Solids | 451 | 293 | 438 | 475 | 594 | na6 | 777 | 500 |
| Hardness (as CaCO3) | 396 | 244 | 380 | 356 | 480 | na | 570 | none7 |
| Iron | 2.3 | 0.09 | 1.5 | 0.0 | 3.6 | 2.3 | na | 0.3 |
| Chloride | 8.0 | 3.2 | 6.0 | 13.0 | 3.0 | 40 | na | 250 |
| 1. Data on wells 1 and 2 taken from Underground Water Resources map M-11 and on wells 3-5, map M-12, ODNR Division of Water; Data on well 6 obtained from Ohio EPA Division of Ground and Drinking Water; Data on well 7 taken from Pickaway County Ground-Water Resources, AEX-490.65. 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. SG--Sand and Gravel; G--Gravel; LS--Limestone. | ||||||||
| 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: Concentrations greater than 0.3 ppm 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. | ||||||||
| 6. Data not available, or constituent not tested. | ||||||||
| 7. No USEPA Secondary Standard. | ||||||||
Ross 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 sand and gravel formations that underlie part of Ross County have the potential to provide excellent water adequate for domestic and agricultural uses, and many industrial and 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 Ross County office of Ohio State University Extension can provide other publications on the county's water resources. Your Extension agent, the Ross County Health Department, and Ohio EPA (Southeast District Office, 2195 Front St., Logan, OH 43138) 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 Ross County, and other information available through the Division. 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 1991 (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.
Background Water-Quality Monitoring, Triangle Sanitary Landfill, South Salem, Ohio. 1992. Eagon & Associates, Inc., Worthington, OH. Report Prepared for Triangle Landfill, Inc.
Floods at Chillicothe (Ross County), Ohio. 1964. G.W. Edelen, F.H. Ruggles and W.P. Cross. U.S. Geological Survey Hydrologic Investigations Atlas 45.
Ground- and Surface-Water Terminology. 1994. L. C. Brown and L. P. Black. AEX 460. Ohio State University Extension.
Ground-Water Pollution Potential of Ross County Ohio. 1991. Report No. 24. ODNR Division of Water.
Ground-Water Resources of Ross County. 1980. J. J. Schmidt, ODNR Division of Water. (map).
Hydraulic Analysis, Paint Creek at State Route 772, Chillicothe, Ohio. 1981. U.S. Geological Survey Open-File Report 81-350.
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. 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.
Underground Water Resources (maps of various river basins). 1958-1962. ODNR Division of Water.
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 Ross County. 1995. R. A. Wells, K. T. Ricker and L. C. Brown. AEX-480.71. 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, Ross County; Ross Soil and Water Conservation District; 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: Doug Pauley (USDA NRCS, Ross County); Maynard Muntzing (OSU Extension Agent, Retired, and Member of Ross County Regional Planning Commission); Dave Cashell (ODNR Division of Water); Scott Golden (Environmental Health, ODH); Steve Hindall (USGS, Ohio District); and Mike Preston (Ohio EPA, SEDO).
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