Ohio State University Extension

Food, Agricultural and Biological Engineering

590 Woody Hayes Dr., Columbus, Ohio 43210

Williams County Ground-Water Resources

AEX-490.86

James J. Hoorman
A. Wayne Jones
Larry C. Brown
Kristina M. Boone

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 Williams 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 Williams County Water Resources, AEX-480.86.

Much of the water resource and water quality terminology used in this publication is described in Extension Facts Sheets AEX 460 and 465. Ohio Extension publications are available through the Williams County office of Ohio State University Extension.

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 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.

Three primary aquifers underlay Williams County: unconsolidated coarse-grained sand and gravel deposits; unconsolidated fine-grained sand and gravel deposits; and low-yielding shale bedrock. The glacially-derived, unconsolidated deposits of water-bearing sand and gravel are major water sources in the county.

The unconsolidated coarse-grained aquifers consist of highly permeable sand and gravel deposited by glaciers. These aquifers are very productive, and may be under artesian pressure in some parts of the county. Fine-grained, unconsolidated aquifers are similar in form and origin to the coarse-grained, unconsolidated aquifers, but are less permeable because of a higher percentage of mixed, fine sands, silt and clay. These sand and gravel deposits usually are embedded in the glacial till, which is an unsorted mixture of clay, sand, gravel and boulders deposited by glacial processes.

Recharge into the unconsolidated aquifers comes from two principal sources. About half of the recharge flows into Williams County as ground water from Hillsdale County, Michigan, and Steuben County, Indiana. The general direction of ground-water flow in Williams County is from the northwest to the southeast. The area northwest of the county is topographical high, and contains the headwaters of several rivers that flow to either Lake Michigan or Lake Erie. The other source of recharge is the county's precipitation.

The unconsolidated deposits that lie along the St. Joseph River basin are a source for sand and gravel for construction and other purposes. Mining sites near Montpelier and Edgerton have been developed to provide a wide variety of building materials. Some of the sand is used in the production of cement. Smaller deposits of beach-ridge sand have limited commercial use.

The shale bedrock is the third type of aquifer found in Williams County. The shale formations were deposited about 380 to 410 million years ago. In most areas of this region, these formations are covered by a layer of glacial till. Shale formations are poor sources of ground water. Low yields of water are possible from some shale in the southeastern portion of the county.

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

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 Ground-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. 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 (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 ground-water resources map for Williams County is currently being developed. The map presented in Figure 1 is a generalized representation of the water-bearing formations underlying Williams County (adapted from St. Joseph River Basin and Tiffin River Basin maps, by Walker, 1959 and 1978). This illustration is based on a hydrogeologic interpretation of the well-log data from Williams 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 2 is a cross section across Williams County (referenced in Figure 1 as the line X-X') showing the relationship of different aquifers, and the thickness of the glacial till above the bedrock.

Figure 1. Ground-water resources of Williams County, Ohio (adapted from Underground Water Resources maps, A-8 and A-9, ODNR Division of Water, by J. Humphreys).

Figure 2. Generalized cross section of Williams County, Ohio (adapted from Underground Water Resources map, A-8, ODNR Division of Water, by R. Roberts).

AREA A: Sand and Gravel

The sand and gravel aquifer illustrated in Figure 1 as Area A covers more than 80 percent of the county, including the St. Joseph River Basin and parts of the Tiffin River Basin. Glacial till, ranging in thickness from 170 to 330 feet, with an average thickness of 250 feet, covers the bedrock. These glacial deposits are composed of coarse sand and gravel. The glacial till in this area is underlain by Mississippian shales, which are poor sources of water.

These sand and gravel deposits usually are adequate sources of water because of their permeability. Most wells have yields adequate for domestic and farm water supplies. Yields of 100 to 500 gpm have been found at depths of 50 to 150 feet. Yields as high as 1,000 gpm are possible with properly constructed wells which encounter thick deposits of coarse material. These wells could supply adequate water for industrial and municipal purposes, as well as for irrigation. Water from this aquifer contains calcium carbonate (CaCO₃, i.e. hard water), and iron concentrations in excess of 0.3 ppm, and may require treatment before being used for many purposes.

AREA B: Sand and Gravel with Flowing Wells

The sand and gravel aquifer, illustrated as Area B, is very similar to Area A in formation. However, this area represents a belt of artesian flowing wells. In Brady and Pulaski townships, differences in ground-water elevations and the ground surface cause many wells to flow when drilled. The ground surface elevation of this area is lower than that of the recharge area. Yields of 500 gpm or more have been found at depths of 60 to 240 feet. Heavy pumping for irrigation or other large water uses may lower the water table in adjacent areas. Intense pumping may reduce the artesian pressure on nearby flowing wells, causing them to stop flowing.

AREA C: Sand and Gravel over Shale

Area C indicates areas of sand and gravel deposits capable of producing more than 100 gpm. Wells drilled into the underlying shale bedrock will encounter minimal yield.

AREA D: Thin Glacial Till underlain by Shale

Shale bedrock underlies the aquifer illustrated as Area D. Only a small portion of Springfield township lies in the area underlain by this shale formation. The bedrock is covered by 35 to 95 feet of glacial till, which consists primarily of clay with intermittent deposits of sand and gravel. Yields generally are adequate for domestic and farm supplies. Yields as great as 20 gpm have been developed at depths ranging from 45 to 90 feet in the glacial till. Yields of 50 gpm or more have been found at depths greater than 235 feet in the bedrock. However, shale bedrock is an extremely dense rock with low permeability, and it seldom is capable of yielding reliable water supplies. The underlying formations consist of non-water-bearing Mississippian and Devonian shales. Water from this formation contains calcium carbonate (CaCO₃, i.e., hard water), and may require treatment before being used for many purposes. Water quality is considered below average because of hardness, objectionable concentrations of sulfate, and dissolved solids concentrations greater than 500 ppm (see notes in Table 1). At depths greater than 50 feet, hydrogen sulfide (rotten egg or sulfur odor) is common. In an attempt to avoid hydrogen sulfide, many wells are drilled to less than 50 feet; however, lower yields can be expected.

Ground-Water Levels

The water level in any well usually does not remain constant, but may change depending upon several factors. Rainfall distribution and amount, and fluctuating water level in a stream that is hydraulically connected to an aquifer, may affect ground-water recharge and discharge, and subsequently may affect the water level in area wells. Also, 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 monitors ground-water levels in three wells in Williams County. Two wells are located near Bryan and are designated as Observation wells Wm-1 and Wm-3 on Figure 1. The third observation well is located near Blakeslee, and is designated as Wm-12. These wells are three of a number of wells throughout northwest Ohio used to monitor the natural seasonal fluctuation on water levels in sand and gravel aquifers. All three of these wells are constructed in a sand and gravel formation, and are representative of many sand and gravel wells in the region.

Observation well Wm-1 (near Bryan) is 118 feet deep, and the depth to bedrock is unknown. Periodic water-level measurements have been recorded at Wm-1 since May 1951, and continuous records since October 1984. The lowest level recorded on Wm-1 was 39.4 feet below land surface in July 1988; the highest level recorded was 1.4 feet below land surface in January 1952. Observation well Wm-3 is 174 feet deep, and the depth to the black shale bedrock is 174 feet. Continuous water-level measurements have been recorded at Wm-3 since October 1984. For Wm-3, the lowest level recorded was 27.4 feet below land surface in June and July 1988; the highest level recorded was 15.4 feet below land surface in January 1987.

Observation well Wm-12 (near Blakeslee) is 115 feet deep, and the depth to shale bedrock is 163 feet. Periodic water-level measurements have been recorded at Wm-12 since 1974. The lowest level recorded on Wm-12 was 10.6 feet below land surface in October 1989; the highest level recorded was 3.8 feet below land surface in March 1982.

Ground-Water Quality

Various state and federal agencies have participated in programs to determine the ground-water quality in Ohio. For six wells in Williams 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 6. These sites are either municipal or industrial wells.

The results from some of the chemical tests performed on these Williams County wells are given in Table 1. The chemical constituents listed are total dissolved solids, hardness (as CaCO₃), iron, chloride and pH. 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.

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 the water at the time of sampling, which was not the same for all wells. In most cases, the data provided in Table 1 was taken from a water sample obtained just after the well was put into operation. Even though all six of these wells were developed in the sand and gravel deposits underlying Williams County, and are in the range of 90 to 154 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 the properties of the geologic formation 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 Williams County wells1.
Well No.	1	2	3	4	5	6	WQ Std2
Well Depth (feet)	101	143	122	154	97	90
Capacity (gpm)	200	200	1500	465	200	300
Depth to Bedrock (feet)	NE3	NE	NE	NE	NE	NE
Water-Bearing Formation4	SG	SG	SG	SG	SG	SG
Chemical Constituents5
Total Dissolved Solids	342	607	385	408	368	376	500
Hardness (as CaCO3)	494	246	302	314	331	314	none6
Iron	4	0.6	0.8	2.7	2.2	3.0	0.3
Chloride	20	176	12	20	12	6	250
pH	7.6	7.5	7.5	7.6	7.6	7.4	none
1 Data on wells 1-3 from watershed map A-8; wells 4-6 from watershed map A-9; 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.
5 Units are parts-per-million, ppm; A pH of 7.0 is neutral. 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, which may affect the taste of beverages made from the water. Chloride: Concentrations greater than 250 ppm may result in an objectionable, salty taste to water and the corrosion of plumbing in the hot water system.
pH: Is expressed on a scale of 1 (acidic) to 14 (basic).
6 No USEPA Secondary Standard.

Summary

Williams 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. More than 75 percent of the county is underlain by a limestone formation that has the potential to supply water adequate for domestic and agricultural uses, 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 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.

Where to Get More Information

The Williams County office of Ohio State University Extension can provide other publications on the county's water resources. Your Extension agent, the Williams County Health Department, and Ohio EPA Northwest District Office - NWDO (347 North Dunbridge Rd., Bowling Green, OH 43402) 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 ODNR ground-water maps of the county, and other information available through the Division of Water. This map is much more detailed than that given in Figure 1 of this publication. In addition, personnel in the Ground-Water Resources Section can provide you with more detailed information about ground-water availability and wells. The USGS, Ohio District (975 W. Third Ave. Columbus, OH 43212), also provides information concerning ground water in Ohio.

Bibliography

Ground-Water Resources of Williams County, Ohio. 1984-86. U.S. Geological Survey, Water-Resources Investigations Report 89-4020.

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. 1993. R. Leeds and L.C. Brown. AEX 465. Ohio State University Extension.

Northwest Ohio Water Plan. 1967. ODNR Division of Water.

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.

St. Joseph River Basin, Underground Water Resources. 1959. A.C. Walker, Geologist. ODNR Division of Water. Map A-9.

Surface and Ground Water Terminology. 1990. L.C. Brown and L.P. Black. AEX 460. Ohio State University Extension.

Tiffin River Basin, Underground Water Resources. 1978. A.C. Walker, Geologist. ODNR Division of Water. Map A-8.

Underground Water Resources (maps of various river basins). 1958-1962. ODNR Division of Water.

Water Testing. 1988. K. Mancl. AEX 314. Ohio State University Extension.

Williams County Water Resources. 1993. J.J. Hoorman, K.M. Boone and L.C. Brown. AEX-480.86. Ohio State University Extension.

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; Ohio State University Extension, Williams County; Williams County Commissioners; Williams Soil and Water Conservation District; Overholt Drainage Education and Research Program; and USDA Extension Service Grant No. 90-EWQI-1-9018. The project leaders acknowledge the following reviewers: Mark Jacoby and George Derringer (USDA-Soil Conservation Service); Jean Wize and Jim Watkins (Williams County Combined Health Department); Scott Golden (Environmental Health, ODH); Steve Hindall (USGS, Ohio District); and Tim Fishbaugh (Ohio EPA, NWDO).

A special thanks to Michelle Roby, Ross Roberts, and John Humphreys (Agricultural Engineering Undergraduate Assistants) for help in graphic and manuscript preparation, and Judy Kauffeld, Publications Editor (Section of Communications and Technology, Ohio State University), for editorial and graphic production.