Ohio State University Extension

Food, Agricultural and Biological Engineering

590 Woody Hayes Dr., Columbus, Ohio 43210

Washington County Ground-Water Resources

AEX-490.84

James M. Barrett
James M. Raab
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 Washington 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 Washington County Water Resources, AEX-480.84, are available through your county Extension office.

Aquifers

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 types of geologic material from which the formation originally was made influence 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 two geological formations that yield ground water in southeastern Ohio and Washington County are: consolidated bedrock consisting of sandstone, shale, limestone or coal; and unconsolidated deposits of sand and gravel. The bedrock aquifers, which range from Mississippian to Permian in age, are dominated by low-yielding shales and shaley sandstones that also include numerous coal-bearing strata. The shale and shaley sandstones are considered poor sources of ground water. Even though well yields are small, these aquifers are a very important source of domestic water supply for southeastern Ohio.

The unconsolidated deposits of sand and gravel, and permeable glacial outwash deposits, adjacent to the Ohio River have a high yield potential. The yield depends on the thickness of the layer containing the sand and gravel deposit, and its proximity to the source of recharge. These wells are recharged by the Ohio River through a process know as induced filtration.

Well Yield

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.

Ground-Water Availability

The Ohio Department of Natural Resources (ODNR), Division of Water, maintains a statewide data base containing over 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 Washington County (adapted from map by Walker, 1984). This illustration is based on a hydrogeologic interpretation of the well log data from Washington 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 Washington County, Ohio (modified from A.C. Walker, ODNR Division of Water, by R.A. Roberts).

AREA A: Coarse-Grained Sand and Gravel

Area A of Figure 1 shows the locations of coarse-grained sand and gravel aquifers in the county. Wells in this aquifer type, which is limited to areas along the Ohio and Muskingum River valleys, have a depth of 25 to 110 feet, and may yield up to 2,000 gpm. The common yield is 100 to 500 gpm. High amounts of iron are common. Figure 2 is a generalized cross section (referenced in Figure 1 as line X-X') of a sand and gravel aquifer along the Ohio River. The "?" in Figure 2 indicates that sufficient data have not been collected to properly characterize these specific locations.

Figure 2. Generalized cross section of sand and gravel aquifer in Washington County, Ohio (modified from A.C. Walker, ODNR Division of Water).

AREA B: Sand and Gravel

The sand and gravel aquifers, shown as Area B, are generally lower yielding than the gravel aquifers of Area A. Wells may yield up to 100 gpm, and water may be found at depths of 25 to 110 feet. This aquifer type also is limited to areas within the Ohio and Muskingum River valleys.

AREA C: Fine-Grained Sand and Gravel

Fine-grained sand and gravel aquifers, illustrated as Area C, are found mostly within the Muskingum River valley. Wells completed in this aquifer typically yield less than 10 gpm.

AREA D: Limestone, Shale and Sandstone

The bedrock aquifer, illustrated as Area D, occurs in 90 percent of Washington County, and is comprised of interbedded layers of sandstone, shale, fireclay, coal and limestone. Well yields are typically less than 3 gpm with some wells yielding up to 5 gpm. Ground-water recharge is very limited in upland areas. Water in some places is soft, but water from this formation throughout the county has a high iron content. Despite the low water yields, this formation is an important water source for some rural residents of the county.

Ground-Water Levels

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 the ground-water level in one well in Washington County: it is located in Marietta and designated as WA-2 on Figure 1. This is one of several wells throughout southeastern Ohio used to monitor the natural seasonal fluctuation, or the effects of nearby pumping, on water levels in the sand and gravel, and sandstone aquifers. Observation well WA-2 is 50 feet deep. Continuous water level measurements have been recorded at WA-2 since August 1971. The lowest level recorded at WA-2 (Marietta) was 40.9 feet below land surface in September 1991; the highest level recorded was 17.6 feet below land surface in January 1991.

Ground-Water Quality

Various state and federal agencies participate in programs to determine the quality of ground water in Ohio. In Washington County, water-quality data were available from ODNR Division of Water and the Ohio EPA Division of Drinking and Ground Water, for observation well WA-2 and six other wells, which are noted as Chemical Analysis Sites 1 through 6 in Figure 1.

The results of some of the chemical tests performed on theses Washington County wells are given in Table 1. The chemical constituents listed are total dissolved solids, hardness (as CaCO₃), iron, sulfate and chloride. All concentrations are given in parts-per-million (ppm). For comparison purposes, 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 six of these wells were developed in sand and gravel formations underlying Washington County and were in the range of 56 to 99 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.

Table 1. Chemical constituents of selected Washington County wells.
Well No.	WA-2	1	2	3	4	5	6	WQ Std1
Well Depth (feet)	50	58	100	61	99	64	56
Capacity (gpm)	225	1,200	2	450	--2	400	400
Depth to Bedrock (feet)	60	NE3	8	61	99	64	56
Water-Bearing Formation4	SG	SG	SS	SG	SG	SG	SG
Chemical Constituents5
Total Dissolved Solids	351	580	627	448	284	546	520	500
Hardness (as CaCO3)	281	340	377	312	173	345	326	None6
Iron	0.05	0	1.4	<0.05	<0.05	<0.05	<0.05	0.3
Sulfate	96	-	-	68	60	65	88	250
Chloride	-	90	16	-	-	-	--	250
1 USEPA Secondary Water Quality Standard.
2 Data not available.
3 Well constructed in this formation did not encounter bedrock.
4 SG-Sand and Gravel; SS-Sandstone.
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. 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. 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. Chloride: High concentrations may result in an objectionable, salty taste to water and the corrosion of plumbing in the hot water system.
6 No USEPA Secondary Standard.

Summary

Washington 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 was designed to provide the reader with 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.

Where to Get More Information The Washington County Extension office can provide other publications on the county's water resources. Your Extension agent, the Washington County Health Department 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 Washington 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 West Third Ave., Columbus, OH 43212), also provides information about ground water in Ohio.

Bibliography

Ground-Water Resources for Washington and Morgan Counties. 1984. 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.

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.

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.

Underground Water Resources - Muskingum River Basin, P-19. 1962. Ohio Water Plan Inventory. ODNR Division of Water.

Washington County Water Resources. 1992. J.M. Barrett, K.M. Boone and L.C. Brown. AEX-480.84. Ohio Cooperative Extension Service, The Ohio State University.

Water Testing. 1988. K. Mancl. AEX-314. Ohio Cooperative Extension Service, The Ohio State University.

Acknowledgments

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; Washington County Extension office; Overholt Drainage Education and Research Program; and USDA Extension Service Grant No. 90-EWQI-1-9018. The project leaders acknowledge the following reviewers: David Cashell (ODNR Division of Water); Scott Golden (Environmental Health, ODH); Robert Gustafson (Agricultural Engineering, OSU); Steve Hindall (USGS, Ohio District); and Michael Preston (Ohio EPA Division of Drinking and Ground Water).

A special thanks to Michelle Roby and Ross A. Roberts (Agricultural Engineering Undergraduate Assistants) for help in manuscript and graphics preparation, and Judy Kauffeld and Tonya Ewing (Section of Information and Applied Communications, OSU Extension) for editorial and graphic production.