Figure 1. Average monthly precipitation in Union County, 1951-1980.
John Hixson
Larry C. Brown
Water is a resource often taken for granted. In recent years, water availability and quality have become important public concerns in Union County. The total county land area comprises 279,000 acres: residential and commercial purposes account for 12 percent of the land use, while the remainder is farmland. Despite this high percentage of farmland, Union County's rural and city populations are both rapidly increasing. As a result of this strong development pattern, both domestic and industrial demands for water are increasing. Union County's 32,000 residents (1980 census population was 29,536), following national trends of increased awareness about water, are becoming more conscious of water sources and water quality.
Residents who understand where water is obtained and how it is used in the county gain a better appreciation for their water. This fact sheet provides a brief overview of Union County's water resources, such as rivers, streams, ponds, reservoirs and ground water. Its intent is to increase public awareness and understanding of water resources in Union County. 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. This publication is available through your county Extension office.
According to Ohio Department of Natural Resources records from 1951 to 1980, the average annual rainfall in the county is 35.9 inches. There normally has been a sufficient quantity of surface and ground water for agricultural, industrial and domestic use. Figure 1 illustrates the average monthly precipitation for the 30-year period mentioned above. Based on this long-term precipitation record, the average rainfall was 2.99 inches per month, with February (2.05 inches) typically being the driest month and June (3.92 inches) the wettest. There can be, however, extreme differences in some years and in certain months within a year. Extremes of seasonal and yearly variability are not often seen when considering long-term precipitation information.
Figure 1. Average monthly precipitation in Union County, 1951-1980.
Union County is part of the Scioto River Basin, which drains into the Ohio River. The total Scioto River Basin area of approximately 6,517 square miles is about one-sixth of the state's total area. This basin is of great importance since it is vulnerable to flooding in populated areas, as seen in the floods of 1913 and 1959.
The water resources of Union County consist of surface water from two main streams, a number of smaller streams, numerous small ponds scattered throughout the county and a plentiful ground-water supply. Figure 2 is a generalized map of the surface-water resources of the county. The larger streams are Big Darby Creek and Mill Creek. The Big Darby flows across the southwestern section of the county. Already designated a State Scenic River, the Big Darby is being considered for National Scenic River designation. Parts of this watershed are considered to have an excellent and unique stream habitat, and this has helped promote continued emphasis in the Darby watershed on improved conservation measures to curtail erosion and surface runoff of sediment and agricultural chemicals. In 1991, a USDA Hydrologic Unit Watershed Project was initiated in the Darby Creek Watershed. The purpose of this project is to work with farm producers and other landowners to encourage the use of agronomic practices that will further improve the water quality of Big Darby.
Mill Creek runs from northwest to southeast across the central portion of the county. Water from Mill Creek is withdrawn by the City of Marysville (Ohio Water Service Company) and eventually flows into reservoirs used by the City of Columbus. Many other streams such as Rush Creek, Bokes Creek and Fulton Creek are also important. These and other smaller streams combine to make the total county stream length approximately 535 miles. Fishing and canoeing are the main recreational uses along the larger of these county streams.
Brust Lake (28 acres) is the largest body of impounded water in the county. About 12 other human-made lakes ranging from 5 to 20 acres are located in the county. There are also hundreds of ponds that range in size from 1 4 to 5 acres. The majority of the ponds are filled by precipitation and runoff. These bodies of water are not generally important for agriculture or domestic water supplies, but serve important recreational purposes (fishing, swimming and boating).
Figure 2. Surface-water resources in Union County, Ohio (adapted
from ODNR Division of Water river basin maps).
Ground-water resources in Union County are fair in quality (see water quality section), but are abundant in quantity. Aside from the City of Marysville, which obtains about 66 percent of its water from Mill Creek, the majority of the county population (both rural and urban) gets its drinking water from ground-water sources. The major ground-water source is the carbonate aquifer of limestone and dolomite bedrock. Limestone mainly consists of calcium carbonate; dolomite is very similar but contains magnesium carbonate, as well as calcium carbonate. Both are commonly referred to as limestone, which is familiar to most Ohioans as a construction material.
Yields of water from this aquifer, adequate for domestic and light industrial supplies, are found throughout the county. Well yields in excess of 1,000 gallons per minute (gpm) have been developed at depths ranging from 190 to 270 feet. Farm and domestic wells often supply 10 to 15 gpm at depths of from 40 to 125 feet. In some areas of the county, thin layers of sand and gravel, inter-bedded in thick layers of clay, lie above the limestone bedrock. In these areas, yields of 5 to 10 gallons per minute are common; well depth varies between 50 and 200 feet.
Both the limestone and the sand and gravel aquifers offer a steady supply of water, but the actual yield may differ at specific locations. The yield of a well will vary considerably depending on age and depth of the well and its construction, diameter of the casing, pump capacity and age, and more importantly, properties of the geologic formation. Some of the older wells, at shallow depths, produce only a few gallons per minute, while some newer wells drilled to a greater depth may yield several hundred gallons per minute.
An overview of the ground-water resources in Union County is given in the publication Union County Ground-Water Resources (available through your county Extension office). Specific information on ground-water availability and wells in Union County can be obtained by contacting the Ohio Department of Natural Resources, Division of Water. An additional publication, Ground Water Flow and Water Quality in Northeastern Union County, Ohio, is available from the U.S. Geological Survey.
Based on long-term 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 become runoff, which moves immediately to surface-water bodies like streams and lakes. Two inches are retained at or near 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 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, refer to Fact Sheet AEX-471, Ohio's Hydrologic Cycle, which is available through your county Extension office.
From statewide averages, about 26 percent of the 38 inches becomes runoff and about 16 percent has the potential to recharge aquifers (values for particular locations will differ according to local conditions). Statewide averages applied to Union County's average annual precipitation produce a rough estimate of how many inches may result in runoff and how many inches have the potential to reach aquifers. Based on the statewide averages of runoff and ground-water recharge, Union County's 35 inches of annual precipitation result in about 9 inches of runoff and almost 6 inches have the potential to recharge the aquifers.
Public water use for each of Union County's public water supply systems is given in Table 1, which provides an estimate of population served, water source, estimated daily water usage and treatment plant capacity.
Public water in Union County is supplied by three water systems: Milford Center, Richwood and Ohio Water Service Company, Marysville. Milford Center uses two wells with one stand-by well. Richwood uses three wells to supply water. The Ohio Water Service Company in Marysville supplies water from both surface- and ground-water sources; about 66 percent of its water is obtained from the Mill Creek impoundment, and 34 percent from four wells.
| Table 1. Water Use in Union County, Ohio.1 | ||||
|---|---|---|---|---|
| Public Water System | Population Served | Primary Water Source | Water Usage (GPD)2 | Treatment Plant Capacity (GPD) |
| Marysville3 | 9,500 | Surface Water4 | 1,370,000 | 2,200,000 |
| Milford Center | 800 | Ground Water | 65,000 | 150,000 |
| Richwood | 7,200 | Ground Water | 205,000 | 288,000 |
| 1 Estimates were abstracted from The Central Ohio Water Plan (1977) and adjusted using 1990 data provided by Gary Cutler, Ohio EPA, Division of Public Drinking Water, Columbus, OH. | ||||
| 2 GPD = Gallons per Day. | ||||
| 3 Ohio Water Service Company. | ||||
| 4 This plant obtains about 66 percent from surface water and 34 percent from ground water. | ||||
While both surface and ground water are plentiful resources in the county, the presence of certain minerals and agricultural chemicals in the water has caused some concern about water quality. Most of the minerals are naturally occurring, such as iron, sulfates, dissolved solids and others, and water hardness is a problem in certain areas. In certain situations, sediment, agricultural chemicals and nutrients run off from farm fields into surface-water supplies. Water quality in Mill Creek is of concern relative to the application of crop nutrients; nitrate levels that exceed 10 mg/L, the safe drinking water standard, are detected seasonally. Also, high nitrate levels are cause for concern in the smaller streams of Union County, particularly in Bokes Creek.
Water is a very important resource in Union County. In addition to residential demands, the county has a very strong industrial base and large animal industry (24,700 cattle; 37,000 hogs; 5,600 sheep; and 1.5 million chickens). Clearly, due to high demand, water availability and quality are important public concerns. Water problems can be both costly and inconvenient to correct.
While the present and future availability of water is excellent for Union 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 will help ensure a safe source of water for the future needs of Union County residents, as well as others who eventually use water withdrawn from streams that flow through Union County. This fact sheet is intended to provide information to the public on water facts for Union County. Contact the Union County Extension Service for more information.
Other agencies to contact for more information on these or other water resources topics in Union County include: the Union Soil and Water Conservation District Office; the Ohio Department of Natural Resources, Division of Water (Fountain Square, Columbus, OH 43224, 614/265-6740); the U.S. Geological Survey (Ohio District, 975 W. Third Ave., Columbus, OH 43212); and the Ohio Environmental Protection Agency (1800 WaterMark Drive, Columbus, OH 43266). Your county Extension agent can help you determine which agency to call for your specific needs.
A Special Request ... Many readers of this publication may have access to, or know of other Union County water resources information and facts not included in this publication. If you have accurate and factual information that you would like to pass along, please send copies of those materials to the lead author of this publication at the Union County Extension Office. These materials may help us update the current publication and provide interesting water facts about Union County to the public.
Agricultural Aspects of the Water Development Plan for Central Ohio. 1977. Prepared by Water Resources Committee, 1971-1972, OARDC, and The Ohio State University.
Census of Agriculture. 1987. USDA.
Central Ohio Water Plan. 1977. ODNR Division of Water.
Gazetteer of Ohio Streams. 1960. Ohio Water Inventory Report No. 12. ODNR
Division of Water. Groundwater. 1974. Staff Research Report No. 115, December 1974. Ohio Legislative Service Commission.
Ground Water Flow and Water Quality in Northeastern Union County, Ohio. 1987. K.S. Wilson. U.S. Geological Survey. Water-Resources Investigations Report 87-4083. Prepared in cooperation with the Village of Richwood, Ohio.
Ground-Water Resources of Union County. 1978. J.J. Schmidt. ODNR Division of Water. Map.
Hartstine, L.J., 1991. Historical water records, personal communication. ODNR Division of Water.
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 Division of Water.
Inventory of Ohio's Lakes. 1980. Ohio Water Inventory Report No. 26. ODNR Division of Water.
Inventory of Municipal Water-Supply Systems by County, Ohio. 1977. Ohio Water Inventory Report No. 24. ODNR Division of Water.
Nitrate In Drinking Water. 1987. K.M. Mancl. Bulletin No. 744. Department of Agricultural Engineering, Ohio Cooperative Extension Service, The Ohio State University.
Nitrates and Pesticides in Private Wells in Ohio, June 1989. Water Quality Laboratory, Heidelberg College, Tiffin, Ohio.
Ohio Agricultural Statistics. 1988.
Ohio Environmental Protection Agency. 1990. Personal communication. Division of Public Drinking Water, Facilities and Operations Section. 1800 WaterMark Drive, Columbus, OH. 43266.
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.
Ohio Surface-Water Resources. USGS National Water Summary, Ohio. 1985. U.S. Geological Survey Water-Supply Paper 2300.
Ohio's Hydrologic Cycle. 1990. L.C. Brown and K.M. Coltman. Fact Sheet No. AEX-461. Department of Agricultural Engineering, Cooperative Extension Service, The Ohio State University. Ohio Information Package, March 1989.
Ohio's Natural Heritage. 1979. M.B. Lafferty (Ed.). Ohio Academy of Science, Columbus, Ohio.
Private Water Systems Handbook. 1987. MWPS-14, Midwest Plan Service, Ames, IA. (Available through Department of Agricultural Engineering, The Ohio State University).
Scioto Basin, Ohio: Comprehensive Study of Water Resources. 1962. Information Bulletin. US Army Engineer District, Huntington. February 1962.
Surface and Ground Water Terminology. 1990. L.C. Brown and L.P. Black. Fact Sheet No. AEX-460. Department of Agricultural Engineering,Ohio Cooperative Extension Service, The Ohio State University.
Union County, Ohio Soil Survey. 1975. USDA, ODNR, and OARDC.
Water Inventory of the Scioto River Basin. 1963. Ohio Water Inventory Report No. 17. ODNR Division of Water.
Water - Ohio's Remarkable Resource. 1982. ODNR Division of Water.
This publication was produced through the Water Resources Educational Materials Project funded by the Innovative Grant Program of the Ohio Cooperative Extension Service, The Ohio State University. Project Team: Larry C. Brown (Project Leader, OSU Extension), Ron Overmyer (Sandusky County, OSU Extension), John Hixson (Union County, OSU Extension), Gary Wilson (Hancock County, OSU Extension), Marcus Dresbach (Northwest District, OSU Extension), Glen Arnold (Putnam County, OSU Extension), Jay Johnson (Agronomy, OSU Extension), Robert Roth (School of Natural Resources, OSU), and Leonard Black and Margo Fulmer (ODNR, Division of Water). The Project Team expresses appreciation to the following for review of this publication: Jim Raab and others (Division of Water, ODNR); Jim Rush, Jan Whitcomb, Wayne Achor, and Gary Overmier (USDA-Soil Conservation Service); Tom Bean (Agricultural Engineering, OSU); Dick Swisshelm (U.S. Geological Survey, Ohio District); and Gary Cutler (Division of Public Drinking Water, Ohio EPA).
A special thanks is given to Doug Stuart (School of Natural Resources, OSU) for help in manuscript preparation, and Judy Kauffeld, Anne Mischo and Sandy Born (Section of Communications & Technology) 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