Marjorie L. Townsend
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 and formations. This publication contains information about the ground-water resources underlying Geauga 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 Geauga County, AEX-480.28.
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 Geauga 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 The material from which the formation was originally made influences its ability to store and transmit water.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.
Consolidated and unconsolidated aquifers are found in Geauga County. The consolidated sedimentary bedrock is composed of alternating layers of sandstone and shale. The shale that is exposed in parts of the county is from the Cuyahoga Formation of the Mississipian Age. The two most important and extensive sandstone formations are the Sharon and Massillon Members of the Pottsville Formation, both of which are of the Pennsylvanian Age.
The retreat of the glaciers left layers of clay-rich glacial till on top of the bedrock. Although this provides some protection from pollution caused by human activity, it also results in reduced well yields. Geauga County is one of the more geologically diverse areas of the state, and this is reflected in its complex drainage systems.
The coarse-grained sand and gravel aquifers found in the south-central part of Geauga County are among the most productive aquifers in Ohio. Additionally, the productivity of well fields developed in such aquifers may be enhanced by induced infiltration from adjacent streams. The unconsolidated sediments found in the northwest corner of Geauga County are mostly fine-grained. These materials are less permeable because of their high percentages of mixed fine sand, silt, and clay. Subsequently, well yields are generally lower in these deposits.
Pottsville Group bedrock consisting of alternating beds of sandstone and shale are found in south-central Geauga County. Glacial deposits cover this Pennsylvanian System bedrock in nearly all of the area. A small area in Burton has permeable deposits of sand and gravel in an ancient buried valley. This is the best well field area in Geauga County.
In the western third of Geauga County, consolidated sedimentary layers of Mississippian and Pennsylvanian age form the bedrock. The Sharon Conglomerate (sandstone) of Pennsylvanian age is the most common bedrock in the area. In northern Thompson and Chardon townships, shale bedrock of the Mississippian System is overlain by thick impermeable clay deposits. Well yields are very poor, and dry wells are not uncommon. In areas of thick glacial deposit cover, adequate domestic and farm water supplies are obtained from wells penetrating discontinuous sand and gravel lenses within the till.
Southward dipping bedrock composed of shale interbedded with water-bearing sandstone is found in Thompson, northern Montville, and northern Hamden townships. The overlying glacial till, ranging in thickness from a few feet to 270 feet, is composed primarily of clay with small amounts of sand and gravel.
In southeastern Geauga County, the overlying glacial till is composed predominantly of clay with occasional lenses of sand and gravel. The hills of Parkman, Huntsburg, and Montville townships are capped by Sharon conglomerate which reaches a maximum thickness of 100 feet.
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 Geauga County. The map presented in Figure 1 is a generalized representation of the water-bearing formations underlying Geauga County (adapted from map by A. C. Walker, 1978). This illustration is based on a hydrogeologic interpretation of the well-log data from Geauga 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 Geauga County, Ohio (adapted from Ground-Water Resources of Geauga County map, A. C. Walker, 1978, ODNR Division of Water; illustration prepared by Carlos Lopez).
Figure 2 is a generalized cross section (referenced in Figure 2 as the line A-A') of a northeastern portion of Geauga County extending to Lake Erie. This cross section shows the range of depth to bedrock as well as the variation in composition of the glacial till, and the Chagrin River Valley.
Figure 2. Generalized cross section of Geauga County, Ohio (adapted from Underground Water Resources map, E-3, ODNR Division of Water; illustration prepared by Kim Wintringham).
Area A denotes the most productive aquifer in Geauga County. Permeable sand and gravel deposited in buried valleys is capable of yielding greater than 1000 gpm to properly constructed wells.
Yields of up to 300 gpm may be obtained from lenses of sand and gravel interbedded with silt and clay in the area illustrated as Area B. Test drilling may be necessary to locate the coarser deposits.
In the areas denoted as Area C, wells will produce sustained yields of 25 to 100 gpm. Yields exceeding 100 gpm may be available for short periods of intermittent pumping. Generally, the bedrock is covered with 15 to 75 feet of glacial material.
Thin lenses of sand and gravel are interbedded with glacial till in the area denoted as Area E. Permeable glacial deposits may yield 10 to 25 gpm. Wells that do not encounter permeable deposits in the till may be drilled into the underlying bedrock to obtain water adequate for farm and domestic uses.
Area F illustrates thick glacial cover over sandstone and shale bedrock. Some wells constructed in sand and gravel in the till above the bedrock may be found, but most wells are constructed in the bedrock where yields of up to 25 gpm are possible.
Discontinuous lenses of sand and gravel interbedded with fine-grained silt and clay are found in valley fill denotes as Area G. Glacial deposits may exceed 200 feet in total depth. Yields of only 3 to 10 gpm are possible.
Area 4-H illustrates areas where yields of less than 3 gpm are common. Additional water storage may be necessary for domestic needs.
The poorest aquifer in the county is denoted as Area I. Impermeable deposits, basically consisting of clay overlying shale or shaley sandstone, have very poor production for even minimal domestic supplies. Dry wells are common.
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 currently does not monitor any wells in Geauga County. However, from 1951 to 1991, the Division did monitor one well located southeast of Chagrin Falls. Observation Well GE-3A was 120 feet deep and the depth to bedrock was approximately 89 feet. Continuous water-level measurements were recorded at the well from 1951 to 1991. The lowest level recorded on Observation Well GE-3A was 52.8 feet below land surface in October 1965; the highest level recorded was 7.6 feet below land surface in April 1991. The Division of Water expects to re-activate this well in the future.
Various state and federal agencies have participated in programs to determine the ground-water quality in Ohio. For 3 wells in Geauga 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 3.
The results from some of the chemical tests performed on these Geauga County wells are given in Table 1. The chemical constituents listed are total dissolved solids, hardness (as CaCO3), iron, chloride, and sulfate. 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.
Table 1. Chemical constituents of selected Geauga County, Ohio, wells.1 | ||||
---|---|---|---|---|
Well No. | 1 | 2 | 3 | WQ Std2 |
Well Depth (feet) | 189 | 85 | 220 | |
Capacity (gpm) | na3 | na | na | |
Depth to Bedrock (feet) | na | na | na | |
Water-Bearing Formation4 | SS | SS/SH | SS | |
Chemical Constituents5 | ||||
Total Dissolved Solids | 198 | 395 | 242 | 500 |
Hardness (as CaCO3) | 164 | 315 | 220 | none6 |
Iron | 4 | 3 | 0.03 | 0.3 |
Chloride | 4 | 6 | 2.7 | 250 |
Sulfate | na | na | 32 | 250 |
1. Data on these wells taken from Underground Water Resources maps, E-1 for sites 1 and 2 and E-3 for site 3, ODNR Division of Water; General location of each well is shown on Figure 1. | ||||
2. USEPA Secondary Water Quality Standard. | ||||
3. Data not available. | ||||
4. SS-Sandstone; SH-Shale. | ||||
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: 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. Sulfate: Concentrations in excess of 250 ppm may have a 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. | ||||
6. No USEPA Secondary Standard. |
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 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 hydrogen sulfide 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 quality of water at the time of sampling. The data provided in Table 1 were taken from a water sample obtained just after the well was put into operation. Even though all of these wells were developed in the sandstone underlying Geauga County, and their depth is in the range of 85 to 220 feet, 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).
Geauga 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 sandstone and shale formations that underlay more than half the area of the county do not have the potential to yield more than 25 gpm, and often yield less. Careful planning of domestic and commercial development is necessary to locate adequate ground-water supplies for these 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 Geauga County office of Ohio State University Extension can provide other publications about the county's water resources. Your Extension agent, the Geauga County Health Department, and Ohio EPA (Northeast District office, 2110 East Aurora Road, Twinsburg, Ohio, 44087) 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 Geauga 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 1994 (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.
Geohydrology, Ground-Water Quality, and Simulated Ground-Water Flow, Geauga County, Ohio. 1990. S. M. Eberts, E. S. Bair, and J. T. de Roche. U.S. Geological Survey Water-Resources Investigations Report 90-4026.
Ground- and Surface-Water Terminology. 1994. L. C. Brown and L. P. Black. AEX 460. Ohio State University Extension.
Ground-Water Conditions in Geauga County, Ohio. 1978. V. E. Nichols. U.S. Geological Survey Water-Resources Investigations Report 80-28.
Ground Water Pollution Potential of Geauga County Ohio. 1994. Report No. 12. ODNR Division of Water.
Ground-Water Resources of Geauga County. 1978. A. C. Walker, 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. 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.
The Silurian Salty Deposits in Eastern Lake, Northwestern Ashtabula, and Northeastern Geauga Counties. Ohio. 1978. S. E. Norris. U.S. Geological Survey Open-File Report 79-269.
Underground Water Resources (maps of various river basins). 1958-1962. ODNR Division of Water.
Water Resources Data, Ohio, Water Year 1995. Volume 2. St. Lawrence River Basin and Statewide Project Data. 1996. U.S. Geological Survey Water-Data Report OH-95-2.
Water Resources of Geauga County. 1995. M. L. Townsend, K. T. Ricker, and L. C. Brown. AEX-480.28. 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, Geauga County; Geauga 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: Allen Bonnis (USDA NRCS Geauga County); Tom Franek (Headwaters Land Trust, and Lake SWCD); Randy James (Ohio State University Extension, Geauga County); Scott Golden (Environmental Health, ODH); Steve Hindall (USGS, Ohio District); and Dave Cashell (ODNR Division of Water).
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.
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