Figure 1. Average monthly precipitation (in inches) in Seneca County, Ohio; (1961-1990) data collected in Tiffin.
Christopher D. Penrose
Chris L. Bruynis
Karen T. Ricker
Larry C. Brown
Water is a resource often taken for granted. In recent years, water availability and quality have become important public concerns in Seneca County. The county's population of 59,930 (1992 Ohio Department of Development estimate) is predominantly rural, and about 50 percent of the households rely on ground water for their water supply. This fact sheet provides a brief overview of Seneca County's water resources, and is intended to help increase public awareness and understanding about this vital resource. By understanding where water is obtained and how it is used in the county, residents can gain a better appreciation for their water supply. 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. Ohio State University Extension publications are available through all Ohio county Extension offices.
An average of approximately 36 inches of precipitation falls on Seneca County annually. Figure 1 illustrates the average monthly precipitation for the county for the period 1961 to 1990. Based on this 30-year record, the average precipitation is 3.0 inches per month, with February (1.9 inches) typically being the driest month, and May (3.9 inches) the wettest. However, there can be extreme variations in some years and in certain months within a year. Such seasonal and yearly extremes may have serious consequences and are not always apparent from the long-term precipitation information.
Figure 1. Average monthly precipitation (in inches) in Seneca
County, Ohio; (1961-1990) data collected in Tiffin.
The Sandusky River is the primary drainage basin for Seneca County. The Sandusky River drainage area encompasses more than 1,420 square miles and has approximately 900 miles of streams (excluding intermittent streams). The Sandusky River flows north through the middle of the county and eventually drains into Sandusky Bay on Lake Erie. A portion of northwestern Seneca County drains into the Huron River, which also drains into Lake Erie. Finally, a portion of southwestern Seneca County drains into a tributary of the Blanchard River, which ultimately drains into Lake Erie. Other major streams besides the Sandusky River include Honey Creek in southeastern Seneca County; Wolf Creek and East Branch of Wolf Creek in western Seneca County; and Rock Creek in east-central Seneca County. A generalized surface-water map of Seneca County is given in Figure 2.
Surface waters are affected by soil type, geology, the topography of adjacent land, and the way people use the land. Land use, such as residential development and agricultural production, may increase the amount of sediment and other pollutants entering a body of water. The soils and terrain also influence the amount of runoff because of infiltration, percolation, and water holding characteristics. With some soils, rainfall is more likely to run off, while other soils allow water to infiltrate more readily.
The county contains approximately 352,640 land acres, of which 85 percent is farmland. Thirty-seven different soil types have been identified in the county, and can be grouped into 10 soil associations. These vary in drainage quality from moderately well drained to poorly drained, in nearly level to sloping soils, formed in predominately glacial till. Since the county is generally level, drainage is a major management concern for farmland and homesites. Only 337 feet separate the highest elevation (978 feet in the southeastern corner of Seneca County) from the lowest elevation (641 feet at the Sandusky River) at the county line in the north-central part of the county.
The county water acreage consists of about 239 acres of lakes, including Clyde Reservoir (110 acres), Garlo Lake (42 acres), Mohawk Lake (10 acres), and several quarries. In addition, there are more than 810 ponds in the county. Approximately 366 linear miles of streams and rivers [estimated from river basin maps, Ohio Department of Natural Resources (ODNR) Division of Water], 219 miles of county-maintained ditches and miles of privately-maintained ditches are used for land drainage.
Figure 2. Surface-water resources in Scioto County, Ohio
(adapted from ODNR Division of Water river basin maps; illustration
by K. A. Weber).
Seneca County's primary ground-water source is a carbonate bedrock aquifer composed of limestone. Limestone is composed of calcium carbonate, while dolomite is composed of calcium and magnesium carbonates. Together they form a popular construction material that most Ohioans refer to as limestone.
In the western and northwestern portions of the county, the carbonate aquifer may produce well yields as much as 100 or more gallons per minute (gpm) at depths less than 200 feet. Yields up to 10 gpm for farm and domestic supplies are developed at depths fewer than 100 feet.
In the central, northeastern, and extreme southwestern corner of the county, the carbonate aquifer has proven well yields of as much as 500 gpm at depths less than 300 feet. Farm and domestic supplies of 10 to 25 gpm are usually encountered at 125-foot depths or less. The east-central and southeastern portion of the county has a relatively thin clayey till above non-water-bearing shale bedrock that will yield less than 2 gpm at depths up to 45 feet. Dry wells are not uncommon and homeowners may rely upon additional storage and/or cisterns to maintain daily requirements. Deep drilling will yield black sulfurous and brackish water. Ground-water supplies have a high natural mineral content often resulting in hard water and usually requires treatment for domestic use. Varying amounts of iron are found and objectional amounts of hydrogen sulfide generally increase with the depth drilled. An overview of the ground-water resources is given in Seneca County Ground-Water Resources, AEX-490.74.
The yield of a well will vary considerably depending on the age and depth of the well, well construction, the diameter of the casing, pump capacity and age, and more importantly, properties of the geologic formation. Specific information on ground-water availability and wells can be obtained by contacting the ODNR Division of Water.
Based on long-term statewide weather records, Ohio receives an average of 38 inches of precipitation per year. These 38 inches move through a complex path called the hydrologic cycle. Of these 38 inches, about 10 inches (26 percent) become runoff, which moves immediately to surface-water bodies such as streams and lakes. Two inches are retained at the ground surface and evaporate back into the atmosphere in a relatively short period of time. Twenty-six of the 38 total inches enter the soil surface through infiltration. Twenty of these 26 inches go into soil storage and later are returned to the atmosphere by the combination of evaporation and transpiration (evapotranspiration). The remaining 6 inches of precipitation (16 percent of the total) have the potential to recharge the ground-water supply. Two of these 6 inches eventually move to springs, lakes, or streams as ground-water discharge. The remaining 4 inches either return to the atmosphere by evapotranspiration or are withdrawn to supply water needs. For more information, please refer to Ohio's Hydrologic Cycle, AEX 461.
Statewide averages applied to the county's average annual precipitation provide a rough estimate of how many inches will result in runoff and how many inches have the potential to reach aquifers. Based on statewide averages of runoff and ground-water recharge, Seneca County's 36 inches of average annual precipitation result in about 9.4 inches of runoff to streams and lakes, and about 6 inches have the potential to recharge aquifers annually. Values for particular locations will differ according to local conditions.
Water use for each of Seneca County's public water supply systems is given in Table 1. For each water system, this table presents an estimate of the population served, water source, estimated daily usage and treatment plant capacity. The county's largest public water system is Tiffin (Ohio American Water Company) that utilizes surface water from the Sandusky River for its supply. Attica and Fostoria also use surface water for their supply, while Bettsville, Bloomville, Green Springs, and Republic all use ground water for their supply.
Ground water is a major water source for rural households in Seneca County. Approximately 40 percent of all households obtain their water from private wells. Based on an estimated usage of 75 gallons per person per day, 1,893,300 gallons per day (gpd) are used. Additional private water uses include industry (1.3 million gpd), golf course and crop irrigation (10,000 gpd), and livestock use (425,000 gpd). Industry, golf course, and irrigation are served mostly from surface water supplies, while livestock use is mainly from ground-water supplies. The remaining 60 percent of households use public-water supplies with ground or surface water as the source, as identified in Table 1.
Some water users in Ohio must register their withdrawals with the ODNR Division of Water. Through the Water Withdrawal Facility Registration Program, owners of facilities capable of withdrawing 100,000 gpd (70 gpm) or more must register those facilities. Information collected through this program includes withdrawal capacity, ground- or surface-water sources, location and type of water use, and location of discharge points. The program is for registration only, and not for allocation or permission. Registered withdrawers file annual reports of their water use. This information helps planners at ODNR to determine the availability of water for projected needs and to better manage and protect Ohio's water resources. Documenting water use also provides official records for individual uses. For more information, contact the ODNR Division of Water.
| Table 1. Water Use in Seneca County, Ohio.1 | ||||
|---|---|---|---|---|
| Public Water System | Population Served | Primary Water Source | Water Usage (GPD)2 | Treatment Plant Capacity (GPD) |
| Tiffin (OH American Water Co.) | 18,529 | Surface Water | 1,980,000 | 3,430,000 |
| Fostoria* | 10,957 | Surface Water | 2,183,000 | 6,000,000 |
| Attica | 1,200 | Surface Water | 211,000 | 479,000 |
| Bloomville | 991 | Ground Water | 85,000 | 317,000 |
| Bettsville | 740 | Ground Water | 75,000 | 337,000 |
| Green Springs* | 730 | Ground Water | 158,000 | 346,000 |
| Republic | 655 | Ground Water | 50,000 | 698,000 |
| Other3 | 864 | Ground Water | 94,550 | N/A |
| *Population figures reported are for the population of Fostoria and Green Springs residents living in Seneca County. | ||||
| 1 Estimates from Ohio EPA using adjusted 1994 data; information is based on data available at time of publication. | ||||
| 2 GPD = gallons per day. | ||||
| 3 Includes mobile home parks, Flat Rock Care Center, and St. Catherines Care Center. | ||||
Human activities and natural processes affect the quality of our water supplies. Throughout Ohio, human activities contribute to both point and nonpoint source pollution. Point source pollution is the introduction of impurities into water (ground water or surface water) from an identifiable, known location. Examples of point sources can include industrial factories, power plants, commercial businesses, and wastewater treatment facilities.
Nonpoint source pollution also involves the introduction of impurities into a surface-water body or an aquifer, except the route is usually non-direct and the sources are diffuse in nature. A major portion of the sediment, nutrients, acids and salts, heavy metals, toxic chemicals, and pathogens enter the state's water resources through nonpoint source pollution, affecting both ground and surface water. Examples include automobile emissions, runoff from parking lots, and runoff and drainage from agricultural fields, feedlots, home lawns and gardens, residential development, construction, mining, and logging activities.
Natural processes such as precipitation also have an impact on surface water and, to a lesser extent, ground water. For example, rainfall that is acidic ("acid rain") may alter the quality of a stream, lake, or other water resource that receives the rainfall.
As water moves through the fractured limestone underlying Seneca County, it dissolves the minerals contained in these formations and carries them in solution. Publication AEX-490.74 summarizes some of the county's natural ground-water quality aspects.
Human activities, such as agricultural production, domestic waste disposal, and lawn and turf care, may have some influence on the county's ground-water quality. From March of 1990 through April of 1994, a Heidelberg College study sampled 534 county wells for nitrate-nitrogen content, an indicator of water quality. Results showed that 382 wells (72 percent) contained nitrate-nitrogen concentrations in the range of 0 to 0.3 parts-per-million (ppm). This range is assumed to represent natural background levels. Sixty-two wells (11 percent) tested in the range of 0.3 to 3.0 ppm, values that may or may not indicate human influence. The 63 wells (12 percent) that tested in the range of 3.0 to 10 ppm may indicate elevated concentrations resulting from human activities. Only 27 wells (5 percent) tested at more than 10 ppm nitrate-nitrogen, which exceeds the safe drinking-water standard. Most of the wells that tested high for nitrate content were in the northeast corner of the county where there are numerous sinkholes. Sinkholes enable water to rapidly enter ground water systems, and do not provide any filtering of contaminants.
The design, location, and condition of a well, combined with the characteristics of the soils and geologic formations in which the well is constructed, influence the potential for pollutants to enter the well. The Seneca County Department of Health provides bacteriological water sampling for local citizens, and results of these tests generally indicate acceptable drinking water in the county.
Runoff and sediment from residential development, construction sites and agricultural lands may enter the county's streams and lakes. Also, runoff may carry other pollutants, such as lawn and agricultural chemicals (pesticides and fertilizers), effluent from septic systems, oil and gas from spills, and industrial wastes.
Through the State of Ohio Nonpoint Source Assessment and the Water Resources Inventory, the Ohio Environmental Protection Agency (Ohio EPA) has identified 13,000 stream miles in Ohio that have been affected by nonpoint source (NPS) pollution. Based on the findings of the Assessment and Inventory, the Ohio Nonpoint Source Management Program has been implemented to help improve the quality of the state's waters.
Water quality monitoring indicates that all or parts of the following Seneca County streams are affected by NPS pollution: Sandusky River (Sycamore Creek to Bells Run; Bells Run to Wolf Creek), Wolf Creek, Honey Creek (Broken Knife Creek to Silver Creek), and Slate Run. These streams are affected by one or more of the following NPS pollution categories: agriculture, crop production, surface runoff, on-site wastewater treatment systems, channelization, and in place pollutants. Other county streams in the county are affected by point source pollution (municipal and/or industrial wastewater). Point source affected streams include Sugar Creek and Raccoon Creek. Seneca County also contains streams that have good water quality and are attaining chemical and biological water quality standards. Monitoring has shown that all or parts of the following streams have good water quality: Honey Creek (Silver Creek to Sandusky River), Green Creek, Willow Creek, Rock Creek, and Indian Creek. For specific information about the streams listed in the Assessment and Inventory documents, and details about the Nonpoint Source Management Program, contact the Ohio EPA Northwest District Office (347 North Dunbridge Rd., Bowling Green, OH 43402). Information about nonpoint source pollution is also discussed in Nonpoint Source Pollution: Water Primer, AEX 465, available from your county Extension office.
It is important to note that as of June 1995 less than half of Ohio's streams have been evaluated by the Assessment. As water quality monitoring continues statewide, the list of Seneca County affected streams and streams with good water quality will change. Residents have a major responsibility to protect Seneca County's water resources from pollutants that could affect the quality of the water supply.
Water availability and quality are important public concerns. Water problems can be both costly and inconvenient. While the present availability of water is good for Seneca County, water is a precious resource that must be conserved and protected. We must all work together to maintain an adequate supply of good quality water.
This fact sheet provides information about the water resources in Seneca County. For more information concerning water resources and drinking-water quality in the county, contact the Seneca County office of Ohio State University Extension (155 E. Perry St., Tiffin, OH 44883-2389; 419-447-9722). In addition, the following agencies may be able to provide information on other water resources topics in the county: Seneca Soil and Water Conservation District; Seneca County Health Department; ODNR Division of Water (Fountain Square, Columbus, OH 43224); U.S. Geological Survey (USGS), Ohio District (975 W. Third Ave., Columbus, OH 43212); Ohio EPA (P.O. Box 1049, Columbus, OH 43216-1049); and Ohio Department of Health (ODH; P.O. Box 118, Columbus, OH 43226).
1990 Census and 1992 Estimates of Ohio's Population: State, Counties, Cities, and Villages. 1994. Ohio Department of Development.
Doane's Agricultural Report. 1992. Farm Water Systems.
Estimated Water Use in Ohio, 1990, Public Supply Data. 1993. USGS. Open-File Report 93-72.
Gazetteer of Ohio Streams. 1960. Ohio Water Inventory Report No. 12. ODNR Div. of Water.
Ground-Water Resources of Seneca County. 1982. D. E. Keen. ODNR Div. of Water. (map).
Hydrologic Atlas for Ohio: Average Annual Precipitation, Temperature, Streamflow, and Water Loss for the 50-Year Period 1931-1980. 1991. L. J. Hartstine. Water Inventory Report No. 28. ODNR Div. of Water.
Inventory of Municipal Water-Supply Systems by County, Ohio. 1977. Ohio Water Inventory Report No. 24. ODNR Div. of Water.
Inventory of Ohio's Lakes. 1980. Ohio Water Inventory Report No. 26. ODNR Div. of Water.
Monthly Station Normals of Temperature, Precipitation, and Heating and Cooling Degree Days, 1961-90, Ohio. 1992. Climatology of the United States, No. 81 (by state). NOAA.
Nitrate and Pesticides in Private Wells of Ohio: A State Atlas. 1989. Water Quality Laboratory, Heidelberg College.
Nitrate in Drinking Water. 1987. K. M. Mancl. Bulletin No. 744. Ohio State University Extension.
Nonpoint Source Pollution: Water Primer. 1993. R. Leeds and L. C. Brown. AEX 465. Ohio State University Extension.
Ohio Department of Agriculture. 1992. Annual Report and Statistics.
Ohio Ground-Water Quality. USGS National Water Summary-Ohio. 1986. USGS. Water-Supply Paper 2325.
Ohio Ground-Water Resources. USGS National Water Summary- Ohio. 1984. USGS. Water-Supply Paper 2275.
Ohio Nonpoint Source Management Program. 1993. ODNR.
Ohio Surface-Water Resources. USGS National Water Summary- Ohio. 1985. USGS. Water-Supply Paper 2300.
Ohio Water Firsts. 1985. S. L. Frost and W. S. Nichols. Water Resources Foundation of Ohio, Inc.
Ohio Water Resource Inventory: Executive Summary and Volumes 1-4. 1992. Ohio EPA.
Ohio's Hydrologic Cycle. 1990. L. C. Brown and K. M. Coltman. AEX 461. Ohio State University Extension.
Private Water Systems Handbook. 1987. MWPS-14. Midwest Plan Service, Ames, IA.
Seneca County, Ohio Soil Survey. 1979. USDA-NRCS.
Seneca County Ground-Water Resources. 1995. C. D. Penrose, C. L. Bruynis, A. W. Jones, L. C. Brown and K. T. Ricker. AEX-490.74. Ohio State University Extension.
Seneca Soil and Water Conservation District Resources Inventory. 1982. USDA-NRCS.
State of Ohio Nonpoint Source Assessment: Volumes 1-6. 1990. Ohio EPA.
Surface and Ground Water Terminology. 1990. L. C. Brown and L. P. Black. AEX 460. Ohio State University Extension.
Thompson Township Water Quality Special Project. 1992. Seneca Soil and Water Conservation District.
Water-Ohio's Remarkable Resource. 1982. ODNR Div. of Water.
Withdrawal and Distribution of Water By Public Water Supplies in Ohio, 1985. 1989. USGS. Open-File Report 89-423.
This publication was produced through the Ohio Water Resources Education Project, in cooperation with: ODNR Division of Water; Ohio EPA; USGS, Ohio District; and ODH. Project leaders are Larry C. Brown and Karen T. Ricker. Partial financial support for this publication was provided by these cooperating agencies and programs: Seneca County office of OSU Extension; Seneca County Commissioners; Overholt Drainage Education and Research Program; and the Ohio Management Systems Evaluation Area Project (USDA Extension Service Grant No. 90-EWQI-1-9018).
The project leaders express appreciation to the following reviewers: Ada Jahns (Seneca Soil and Water Conservation District); Scott Miller (USDA Natural Resources Conservation Service, Seneca, Wyandot, and Crawford Counties); A. Wayne Jones, James M. Raab, David Cashell and Leonard Black (ODNR Division of Water); Scott Golden (Environmental Health, ODH); Steve Hindall (USGS, Ohio District); Anthony J. Kramer (USDA Natural Resources Conservation Service, State Office, Columbus); Jay Fleming (Ohio EPA Division of Drinking and Ground Waters); and Larry Antosch, Rich McClay, and Mark Wilson (Ohio EPA Division of Surface Water).
A special thanks to 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