Figure 1. Ground-water resources of Shelby County, Ohio (modified from R.J. Kostelnick, ODNR Division of Water, by R.A. Roberts).
Roger Bender
A. Wayne Jones
Kristina M. Boone
Larry C. Brown
Water stored under the earth's surface is a plentiful, yet precious, resource in most areas of Ohio. Humans greatly affect ground water. However, the availability and quality of this resource are influenced directly by the properties of the geologic formation that holds 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 Shelby County. Its purpose is to help the reader better understand the factors that influence the quantity and quality of ground water. Water resources terminology used in this publication is included in Surface and Ground Water Terminology, fact sheet AEX-460, which provides a listing of generally accepted water resource definitions. Fact sheet AEX-460 and the publication Shelby County Water Resources, AEX-480.75, are available through your county Extension office.
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, sands and gravels 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 carbonate aquifer, which is composed of layers of limestone and dolomite, is the principal source of ground water in west central Ohio, including Shelby County. Limestone consists of fossilized sea shells, shell fragments, calcareous sands and consolidated limy mud. Its 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. Both limestone and dolomite are commonly referred to as limestone or carbonate rocks. The limestone and dolomite formations, which underlie most of the western portion of Ohio, were deposited between about 400 and 500 million years ago. In most areas of this region, these formations are covered by a layer of glacial till, which is an unsorted mixture of clay, silt, sand, gravel and boulders deposited by glacial activity.
Limestone formations are usually good sources of ground water because of their naturally formed solution channels, joints and fractures, which provide water storage capacity and pathways for water movement. The number of fractures and other openings in limestone 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 openings rarely can be determined from the land surface; therefore, there is always some uncertainty as to the production capability of a proposed well.
Ground water also occurs in lenses (or pockets) of sand and gravel deposited by glacial activity. These deposits occur above the carbonate bedrock and may be imbedded in the glacial till or deposited in layers.
The actual 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.
The Ohio Department of Natural Resources (ODNR), Division of Water, maintains a statewide data base of more than 700,000 well logs. The Ground-Water Resources Section of the Division manages this valuable data base, 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. Geologists and hydrogeologists continue to study the state's ground-water resources, and as a result, Ohio is one of only a few states that has been completely mapped for ground-water availability (mapped by river basin, from 1959 to 1962).
Estimates of the size, shape, geologic make-up and yields of aquifers are being mapped county by county. Most of Ohio's counties have a completed map. The map presented in Figure 1 is a generalized representation of the water-bearing formations underlying Shelby County (adapted from map by Kostelnick, 1983). This illustration is based on a hydrogeologic interpretation of the well log data from Shelby County and surrounding areas. It should be used only as a guide to understanding the ground-water resources in the county. The remainder of this section provides a brief description of the types of aquifers illustrated on the map in Figure 1.
Figure 1. Ground-water resources of Shelby County, Ohio
(modified from R.J. Kostelnick, ODNR Division of Water, by R.A.
Roberts).
Area A in Figure 1 illustrates the outwash sand and gravel deposits in the Loramie and Turtle Creek flood plains. These areas may yield large water supplies to properly screened wells. Well yields of up to 500 gpm generally can be obtained from depths of less than 75 feet.
This buried valley, illustrated as Area B, is a tributary to the ancestral Teays River valley. Commonly misunderstood to be an underground river, the Teays valley is a remnant of an ancient drainage system that cut a valley into the limestone before the area was glaciated. Later, with the coming of glaciers, the valleys were completely filled with glacial deposits. Intermittent deposits of sand and gravel can be found interbedded with thick layers of clay-rich glacial till.
Deep sand and gravel deposits in the ancestral Teays valley may yield small industrial and municipal supplies. The coarsest deposits generally occur between 100 and 300 feet below the surface. Yields of up to 500 gpm are possible from properly-constructed wells. Flowing wells have been noted near Salem and Perry townships. Test drilling may be necessary to locate the coarser deposits that have the potential for maximum yields. Deeper drilling into the impermeable shale in the valley floor is not advised.
The limestone aquifer illustrated as Area C is part of the regional carbonate aquifer which underlies much of west central Ohio. It is overlain by 15 to more than 200 feet of glacial till, consisting principally of clay with intermittent deposits of sand and gravel. Most wells are drilled into the limestone, and yields generally are adequate for domestic and farm water supplies. Where openings in the rock have been enlarged by solution, drilled wells may yield over 150 gpm.
Figure 2 is a generalized cross section (referenced in Figure 1 as line X-X') of a portion of Shelby County. This cross section shows the range in depth to bedrock as well as the variation in composition of the glacial till. Three hypothetical wells are shown on the cross section to illustrate various conditions that may be encountered in this area. Well #1 in Figure 2 extends through approximately 75 feet of non-water-bearing till and is developed in the underlying limestone bedrock. Well #2 may supply domestic requirements from limited sand and gravel deposits above the bedrock, although larger supplies are probable in the limestone. Well #3 is supplied by extensive sand and gravel deposits in deep glacial till. The "?" in Figure 2 indicates that sufficient data have not been collected to properly characterize this specific area.
Figure 2. Generalized cross section of Shelby County, Ohio
(modified from Underground Water Resources map, H-2, ODNR Division of Water).
Ground-water supplies, whether they are developed from bedrock or glacial deposits, will require some treatment. High levels of hardness and iron can be encountered, and wells drilled into shale or limestone may produce water that is high in hydrogen sulfide. In general, the probability of obtaining sulfur in objectionable amounts increases with the depth drilled.
Area D is also part of the regional carbonate aquifer of west central Ohio. However, the water-bearing bedrock is thinner than in similar formations to the north. Yields of 25 to 100 gpm, considered adequate for industrial and municipal water supplies, may be developed from this aquifer at depths of less than 200 feet. Farm and domestic water supplies can usually be developed at depths of 60 to 120 feet.
Area E shows the thin outwash deposits in the Loramie Creek area. Shallow, irregular sand and gravel deposits within 75 feet of the surface may yield 25 to 100 gpm to properly screened wells.
Area F outlines the thin bedrock surface surrounding ancestral valleys. Well yields vary from 10 to 25 gpm from the thin limestone and shale present.
Thick clay, fine sand, and gravel over impermeable bedrock are found in these ancestral drainage channels, shown as Area G. Yields of 3 to 10 gpm may be developed for domestic supplies in the valley fill material. However, deeper drilling into the shale is not recommended, since dry holes do occur.
The water level in any well typically does not remain constant, but changes depending upon the proximity of adjacent wells and surface streams, and natural rainfall. Ground-water discharge and recharge greatly affect water levels in wells. The ODNR Division of Water monitors ground-water levels in one well in Shelby County. This well is located near Sidney and designated as SH-4 on Figure 1. This well is one of a number of wells throughout west central Ohio used to monitor the natural seasonal fluctuation, or the effects of nearby pumping, on water levels in the carbonate aquifer.
Observation well SH-4 is 280 feet deep and the depth to limestone is approximately 136 feet. It is representative of many limestone wells in the region. Continuous water level measurements have been recorded at SH-4 since September 1979. The lowest level recorded on SH-4 (Sidney) was 94 feet below land surface in October of 1982; the highest level recorded was 56 feet below land surface in April and June of 1990.
Various state and federal agencies have participated in programs to determine the ground-water quality in Ohio. For five wells in Shelby County, water-quality data were available from the ODNR Division of Water and the Ohio EPA Division of Drinking and Ground Water. In Figure 1, these wells are noted as Chemical Analysis Sites 1 through 5. These sites are municipal or commercial wells.
The results of some of the chemical tests performed on these Shelby 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 are also 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). There are no drinking water-quality standards for private wells.
The information in Table 1 can be used as a guide to what one might expect from an existing or new well. Even though four of these wells were developed in the limestone underlying Shelby County, and all are in the range of 110 to 231 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.
| Table 1. Chemical constituents of selected Shelby County wells. | ||||||
|---|---|---|---|---|---|---|
| Well No. | 1 | 2 | 3 | 4 | 5 | WQ Std1 |
| Well Depth (feet) | 110 | 214 | 231 | 105 | 200 | |
| Capacity (gpm) | 100 | 200 | 200 | 45 | -2 | |
| Depth to Bedrock (feet) | NE3 | 114 | 80 | 100 | - | |
| Water Bearing Formation4 | G | LS | LS | LS | LS | |
| Chemical Constituents5 | ||||||
| Total Dissolved Solids | 566 | 901 | 527 | 951 | 519 | 500 |
| Hardness (as CaCO3) | 470 | 610 | 400 | 668 | 425 | None6 |
| Iron | 1.7 | 3 | 1.4 | 6.6 | 1.5 | 0.3 |
| Chloride | 0 | 3 | 9 | 5.8 | 7 | 250 |
| Sulfate | - | - | - | 484 | 72 | 250 |
| 1 USEPA Secondary Water Quality Standard. | ||||||
| 2 Data not available. | ||||||
| 3 Well constructed in this formation did not encounter bedrock. | ||||||
| 4 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 rust-colored stains on laundry, plumbing fixtures and sinks. Metallic taste may be present and 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 havej laxative effect on persons unaccustomed to the water; also affect the taste of water and will form a hard scale in boilers and heat exchangers. | ||||||
| 6 No USEPA Secondary Standards. | ||||||
Shelby 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. By understanding the physical and chemical nature of these resources, better decisions can be made about ground-water protection, management and use. This publication provided 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 Shelby County Extension office can provide other publications on the county's water resources. Your Extension agent, the Shelby County Department of Health and Ohio EPA Division of Drinking and Ground Water (1800 WaterMark Drive, Columbus, OH 43266) can provide information on well-water testing and drinking-water quality. The ODNR Division of Water - Ground-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 Shelby County, and other information available through the Division of Water. This map is much more detailed than that given in Figure 1, and the Ground-Water Resources Section can provide detailed information on ground-water availability and wells. The USGS, Ohio District (975 W. Third Ave. Columbus, OH 43212), also provides information about ground water in Ohio.
Ground-Water Resources of Shelby County. 1983. R.J. Kostelnick. 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.
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.
Shelby County Water Resources. 1992. R. Bender, K.M. Boone and L.C. Brown. AEX-480.75. Ohio Cooperative Extension Service, The Ohio State University.
Southwest Ohio Water Plan. 1976. ODNR Division of Water.
Surface and Ground Water Terminology. 1990. L.C. Brown and L.P. Black. AEX-460. Ohio Cooperative Extension Service, The Ohio State University.
Underground Water Resources (maps of various river basins). 1958-1962. ODNR Division of Water.
Water Testing. 1988. K. Mancl. AEX-314. Ohio Cooperative Extension Service, The Ohio State University.
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 Kristina M. Boone. Support for this publication was provided, in part, by: cooperating agencies; Shelby County Extension office; Shelby County Commissioners; USDA Water Quality Initiative Funds; Lake Loramie Joint Water Quality Task Forces; Overholt Drainage Education and Research Program; and USDA Extension Service Grant No. 90-EWQI-1-9018. The project leaders acknowledge the following reviewers: Deba Mohler (USDA-Soil Conservation Service); Roger Lentz (USDA-Agricultural Stabilization and Conservation Service); David Cashell (ODNR Division of Water); Scott Golden (Environmental Health, ODH); Tom Bean (Agricultural Engineering, OSU); Steve Hindall (USGS, Ohio District); and Rich Bendula (Ohio EPA Division of Drinking and Ground Water).
A special thanks to Anita Barker and Karen Cole (Shelby County Extension), and Michelle Roby and Ross A. Roberts (Agricultural Engineering Undergraduate Assistants) for help in graphics and manuscript preparation, and Judy Kauffeld and Tonya Ewing (Section of Communications & Technology, OSU 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