Larry C. Brown
Nathan L. Watermeier
Ohio citizens have shown increased concern about the wise use and protection of the state's water resources. This concern grows as Ohio citizens are increasingly affected by state regulations and water protection measures brought about by the federal Clean Water Act of 1987 and its subsequent reauthorizations (see Clean Water Act insert). As with most legislation, regulations and protection measures for water are complex, and the terminology may not be readily understandable to most readers.
The purpose of this publication is to help the reader gain a better understanding of the terminology associated with nonpoint source (NPS) pollution and the protection of water resources. The list of terms described here is not comprehensive, but includes terms often used in the context of water-related, nonpoint source pollution in Ohio. This publication is intended for those who at least have a general understanding of water quality.
Related to water resources, nonpoint source pollution is the introduction of impurities into a surface-water body or an aquifer, usually through a non-direct route and from sources that are "diffuse" in nature. Discharges from nonpoint sources are usually intermittent, associated with a rainfall or snowmelt event, and occur less frequently and for shorter periods of time than do point source discharges. Nonpoint sources of pollution are often difficult to identify, isolate and control. "Nonpoint Source" is commonly abbreviated as "NPS."
Examples of NPS pollution include: automobile emissions, road dirt and grit, and runoff from parking lots; runoff and leachate from agricultural fields, barnyards, feedlots, lawns, home gardens and failing on-site wastewater treatment systems; and runoff and leachate from construction, mining and logging operations (see Figure 1). Most NPS pollutants fall into six major categories: sediment, nutrients, acid and salts, heavy metals, toxic chemicals and pathogens, according to the U.S. Department of Agriculture (USDA), and other state and federal agencies. Table I presents a summary of these six categories.
|Table 1. Nonpoint source pollutants and major sources.|
|Sediment||Nutrients (Fertilizers, Grease, Organic Matter)||Acids and Salts||Heavy Metals (Lead, Mercury, Zinc)||Toxic Chemicals (Pesticides, Organic, Inorganic Compounds)||Pathogens (Bacteria, Viruses)|
Pollutants affecting water quality may come from point or nonpoint sources, or a combination of both. Like NPS pollution, point source pollution is the introduction of an impurity into a surface-water body or aquifer. However, the difference is that the point source impurity enters the water resource at an easily identifiable, distinct location though a direct route. Discharges from point sources of pollution often are continuous, and easier to identify and measure compared to NPS discharges. Because of these properties, point sources are somewhat easier to control, although control measures are usually more expensive compared to NPS controls.
Examples of point sources include: industrial plants, commercial businesses and wastewater treatment plants. Point source pollutants are usually municipal or industrial wastes, but are not limited to these.
Figure 1. Examples of nonpoint source pollution.
Ohio citizens should be concerned about NPS pollution because it affects drinking water supplies and the environment. Based on 1992 data from Ohio EPA, NPS pollution affects over 13,700 miles of Ohio's 29,113 perennial stream miles. Twenty-nine percent of these perennial stream miles are classified as impaired (refer to section on Use Designation) as a result of nonpoint source pollution, 45% as impacted, and 25% as threatened. Of Ohio's approximately 450 publicly owned lakes and reservoirs (surface area of 5 acres or greater), 42% are associated with NPS-affected streams segments. Nonpoint source pollution is one of the most complex environmental problems in Ohio, and its impacts are extensive. NPS pollution is now the major contributor to water quality problems throughout Ohio, with sediment ranking as a major pollutant. The combination of sediment and runoff is of particular concern, not only because of the impact of sediment alone, but also because of the wide range of chemicals and other pollutants that travel with runoff (i.e., nitrate, some pesticides and other water-soluble chemicals) and sediment (i.e., phosphorus, some pesticides and other soil-adsorbed chemicals).
A good understanding of water resources terminology is important to better understand nonpoint source pollution. A few water terms are described below. However, much of the water terminology used in this publication is defined in Ground- and Surface-Water Terminology, AEX 460, which is available through your Ohio county office of Ohio State University Extension.
Most people understand surface-water resources since they can be seen. However, the same is not true for ground water. In the broadest sense, ground water consists of all subsurface water. This is all the water in the pores, voids, cracks, fractures and other spaces between soil particles in the soil profile, and in the rock strata of geologic formations. When a geologic formation contains water and can yield significant quantities of water to wells or springs, it is called an aquifer.
The constant circulation of water through the environment by the processes of precipitation, infiltration, percolation, runoff, evaporation, transpiration, ground-water discharge and recharge, and interflow is called the hydrologic cycle. Hydrology is a science dealing with the study of water properties, distribution and circulation. The focus of hydrology is the hydrologic cycle.
The main hydrologic component transporting NPS pollutants to surface-water bodies is runoff, which is driven by precipitation or snowmelt. The effect of this transport mechanism is evident during and after heavy rainfall. Precipitation also is a factor in the movement of pollutants into an aquifer. Pollutants move into an aquifer by infiltration and percolation. The effect of these transport mechanisms is not readily seen because the transport of pollutants occurs underground. However, the potential for pollutant transport to an aquifer is a real concern, especially for soil and geological conditions that allow rapid water movement, e.g., sandy soils, and sand and gravel aquifers. The properties of soils and geologic formations have a substantial effect on many of the hydrologic cycle components. For more information, refer to Ohio's Hydrologic Cycle, AEX 461.
A number of water quality terms are common to many of the nonpoint source pollution implementation projects in Ohio. Some of the most frequently used terms are described in this section.
Water quality is a neutral term that relates to the composition of water as affected by natural processes and human activities. It depends not only on water's chemical condition, but also its biological, physical and radiological condition. The quality of water also is related to its specific use, and usually measured in terms of the concentration of its constituents. The level of water quality and/or pollutant loading is based upon the evaluation of measured quantities and parameters, which then are compared to a set of standards, objectives or criteria. Water quality standards are limits that are established and enforced under state or federal law. They are based on effluent standards, health-based risks, and the availability and use of Best Management Practices (BMP). A water quality objective is a goal usually established by some authority. The authority may have the power to implement control measures and/or appropriate money toward this goal. Water quality criteria are concentration or quantity loading limits. They usually are determined through scientific research from which a judgment about the quality of the resource can be based. Criteria may be based on several factors, including the acute or chronic toxicity of various substances to humans or aquatic life, the related technology available for improving the situation, and even the public's visual preferences.
A pollutant is any substance that is introduced into a water resource, naturally or by human activities, in sufficient amounts to adversely affect the quality of the resource for a specific use. Water pollution refers to the undesirable change in the condition of water to the point where the potential of the water for a specific use is limited or impaired. When the quality of a water resource falls below an acceptable level for a particular use, the water may be classified as polluted or contaminated. Pollution and contamination are very similar in meaning and often are used interchangeably. Contamination historically has related to water containing disease-causing or toxic substances that prevent or reduce the potential for use of that water. In recent times, the term contamination has been used to define the act of degrading the quality of a water supply or making a water supply impure, and to indicate that chemicals, sediments, or bacteriological impurities are present in water.
Concentration refers to the amount of a substance in a specific amount of water at one point in time. For example, if 1,000,000 parts of water contained 10 parts of salt, the salt concentration would be 10 parts-per-million (ppm). For water, the units of parts-per-million is equivalent to milligrams-per-liter (mg/L). Concentration is helpful in determining pollutant levels in which only the quality of the water needs to be considered. For example, the U.S. Environmental Protection Agency (USEPA) has established that the maximum amount of nitrate-nitrogen allowable in public drinking water supplies is 10 parts of nitrate-nitrogen in 1,000,000 parts of water. This concentration can be expressed as 10 ppm or 10 mg/L of nitrate-nitrogen. These levels are usually developed by determining the amount of a pollutant that will result in the water becoming toxic to some organism.
Loading, as with concentration, is a term used to indicate the amount of a pollutant entering or contained in a water resource. The main difference between these two terms is in how the amount of pollutant in the water is expressed, and the time-frame over which the pollutant is generated or released into the water resource. Loading is the total amount of a pollutant generated from a specific area of land, or received by a water resource, during a fixed period of time. It is expressed as the amount of pollutant per unit of land area per unit of time. Typically, loading is stated as tons (or pounds) per acre per year, or metric tons (or kilograms) per hectare per year if using metric units. Loading differs from concentration in that it provides information about the land area producing the pollutant, the time over which the pollutant enters the water resource and the total amount of pollutant delivered.
The delivery ratio is the amount of a pollutant generated at its source compared to the amount of the pollutant actually reaching a water resource. This term is frequently expressed as a percentage. Point and nonpoint source pollutants may have different delivery ratios. A large percentage of many point source pollutants may actually reach a water resource in nearly the same amount as when they were generated and released into the environment. Suppose that a commercial operation generated a waste product as part of a manufacturing process, did not treat the waste, and subsequently discharged the waste directly to a stream. The delivery ratio for this point source case would be near 100 percent. Some NPS pollutants also may have large delivery ratios. As an example, pollution from parking lots where the runoff flows from paved surfaces directly to a storm sewer ot stream may have a large delivery ratio. The delivery ratio for pollutants generated from agricultural land use is variable, but usually ranges between I and 40 percent. For example, much soil may be detached and eroded on an agricultural field during a rainfall event. However, only a small percentage of the sediment may actually enter a stream depending on field slope, soil type, tillage direction, proximity of field to stream, proper use of sediment control methods or BMPs, or other factors that might help reduce runoff velocity and amount, and enhance sediment deposition within the field.
A hydrologic unit is a watershed-area designation that identifies the hydrologic and geographic boundaries of a stream or river basin. A watershed is simply all land in a specific area that drains to one water outlet. The US Geological Survey (USGS), US Water Resources Council, and USDA Natural Resources Conservation Service (NRCS; formerly the Soil Conservation Service, SCS) worked together to delineate the United States into 21 major water resource regions that contain river basins, sub-basins and stream segments. This organization helps water scientists, resource managers, regulatory personnel, and policy makers to better coordinate activities within and across watershed boundaries. In Ohio, there are 93 watersheds, usually containing portions of one or more major streams and their tributaries, and averaging 300,000 acres in size. For the purposes of the Ohio Nonpoint Source Assessment, the Ohio Nonpoint Source Management Plan and the Ohio Water Resource Inventory, Ohio EPA has identified each of these 93 watersheds (also called sub-basins) as a hydrologic group. Each group relates specifically to one of the 93 SCS watersheds in the state. Within these 93 groups, there are over 4,000 stream segments for which the Ohio EPA and cooperating organizations are in the process of conducting water quality assessments.
As part of the Ohio Nonpoint Source Assessment and Ohio Water Resource Inventory (see the insert on Clean Water Act), an "Aquatic Life Use" designation is given to a stream based on the type of aquatic communities an unpolluted stream is capable of supporting. The process takes into account chemical, biological and ecological aspects of the particular region of the state in which the stream is located. This process is supported by the Ohio Administrative Code. The Assessment and Inventory also provide an estimate of the degree to which a stream is attaining its Aquatic Life Use designation as a result of NPS pollution. The indicators are: threatened, impacted and impaired. Threatened streams are those currently meeting or exceeding their designated uses, but current NPS water quality monitoring results indicate pollution potential. When biological and chemical data are insufficient, and/or NPS monitoring results are not conclusive, the stream may not have attained its use designation and is called impacted. Impaired streams are those that cannot attain their use designation based on conclusions from the analysis of biological and chemical data, modeling, and/or NPS monitoring results.
A major activity of many water quality projects is the implementation of Best Management Practices, usually called BMPs. As related to water resources, BMPs are implemented to improve or protect the quality and/or quantity of the resource. In terms of NPS pollution, a BMP is a cultural or engineering technique, or a management strategy, that has been evaluated and accepted to be an effective and practical means of preventing or reducing nonpoint source pollution in a local area. The evaluation and implementation of a BMP, or combination of BMPs, should focus on the management of inputs, and try to provide a balance between economic and environmental considerations. Examples of BMPs include: installing vegetative or forested filter strips between an agricultural land use and a surface-water body to reduce runoff and sedimentation; implementing a conservation tillage practice; implementing an integrated pest management program and pest scouting; locating an on-site wastewater treatment system a proper distance from a well or other water supply; and conducting a soil test and basing decisions about crop nutrient applications upon test results. Three publications, Agricultural Best Management Practices (AEX 464), Best Management Practices for Preventing Contamination of Ohio's Ground and Surface Waters (Bulletin 818), and Crop Production Alternatives (Bulletin 812), are available through your Ohio county office of Ohio State University Extension.
The process of reducing pollutant levels in a water resource, termed abatement, can be accomplished by modifying or eliminating the production of the pollutant, and controlling the transport of the pollutant to the resource. Both the implementation of BMPs and remediation of nonpoint source problems are used in the pollution abatement process. The remediation process for nonpoint source water problems involves the analysis, design, evaluation and implementation of measures, structural or non-structural, to address or correct a water quality problem or concern, or reduce the impact of the problem on the environment. Examples of remediation activities include: evaluation and clean-up operations at a chemical-spill location; removal, disposal and replacement of soil at a site where hazardous wastes have contaminated the soil; treatment of leachate from a leaking landfill; and reclamation of strip-mined areas.
An approach to controlling nonpoint source pollution is getting attention in Ohio and across the country. In 1989, the USEPA announced its commitment to change the agency's traditional focus from Pollution Control to Pollution Prevention, a policy that was expected to change the course of environmental protection. The first component of the Pollution Prevention concept is to eliminate the initial production of wastes and pollutants at the source, which is termed source reduction. However, if wastes and pollutants are generated, the second component is to recycle and reuse the wastes and pollutants in an environmentally sound manner. This concept can be applied to air, soil and water resources. The full implications of Pollution Prevention approaches in Ohio probably are not realized yet.
It is important for the reader to recognize that NPS pollution not only relates to water resources, but to all aspects of our environment. Nonpoint source pollution contributes a major portion of the sediment, nutrients, acids and salts, heavy metals, toxic chemicals and pathogens to Ohio's water resources each year. It is a major factor impacting the quality of the state's water supply, and human activities greatly affect the rate at which NPS pollutants are generated and delivered to water resources. The identification and control of nonpoint source pollution is difficult because of its complex nature.
One of the best ways to control NPS pollution is to implement a BMP. First, identify the source of the pollutant. Then gather information and evaluate the mechanisms that transport the pollutant to the water resource. Based on the results of this evaluation, a Best Management Practice, or combination of BMPs, can be selected and implemented with the goal of providing a balance between the environment land use and economics. Assistance on the selection of proper BMPs is available from your county Extension, Soil and Water Conservation District, and USDA Natural Resources Conservation Service offices. After the BMP plan is implemented, it should be evaluated to determine if its use is helping to achieve the desired result.
This publication presents a description of terms associated with nonpoint source pollution in Ohio. It is intended to serve as a overview for the reader who already has a general understanding of water quality. For more information, refer to the Bibliography or contact your Ohio county office of Ohio State University Extension. For detailed information concerning the results of the Ohio Nonpoint Source Assessment for your area, call or write the Ohio EPA (614/6443020; P.O. Box 1049, Columbus, OH 43266- 0149) for your Ohio EPA district contact.
Responding to public concerns about the quality of the nation's water resources, Congress passed the Federal Water Pollution Control Act Amendments of 1972, better known as the Clean Water Act. The Act stated that "water shall be clean enough for swimming, fishing, and other recreational uses," and "there shall be no unlawful discharge of pollution to US waters." Programs to be implemented through the Clean Water Act were some of the first programs administered by the US Environmental Protection Agency (USEPA). During the 15 years following passage of these amendments, most governmental efforts were directed toward control of point source pollution. These efforts primarily focused on improving industrial and domestic wastewater treatment. In the mid-1980's, government agencies agreed that substantial progress had been made throughout the US to address and correct point source pollution. They further indicated that for a substantial increase in the improvement of water quality, nonpoint sources (NPS) of pollution would have to be addressed.
In 1987, the US Congress amended the federal Clean Water Act of 1972. In these amendments, Section 319 directed each state to develop and implement programs for the control of nonpoint source pollution. As required by the Clean Water Act, the Ohio Environmental Protection Agency (Ohio EPA) and the Ohio Department of Natural Resources (ODNR) developed the Ohio Nonpoint Source Assessment and the Ohio Nonpoint Source Management Program, respectively. The purpose of the "Assessment," developed in 1988 and updated in 1990, was to provide a statewide inventory of the streams, lakes and groundwater areas affected by nonpoint source pollution. In 1992, the Assessment was strengthened by the production of the Ohio Water Resource Inventory (also called the 305b report). The "Management Program" focused upon the water quality problems identified by the Assessment. Developed in 1988 and revised in 1993, the Management Program provided guidance and implementation procedures for state and local agencies and policy makers to address those problems. Both the Assessment and Management Program are components of the State of Ohio Comprehensive Water Quality Management Plan. At present the federal Clean Water Act is under review and revision for reauthorization, possibly to be completed in 1996. A summary of the historical perspective of the federal legislation is provided in Understanding Ohio's Surface Water Quality Standards.
In 1989, the President's Water Quality Initiative brought together several different water resources programs among various federal and state agencies. The principal objective was to provide farmers and landowners with the educational, technical and financial means to respond voluntarily and independently to on-farm environmental concerns and the related state water quality requirements. This national initiative stimulated similar efforts in Ohio that led to federal and state agencies joining forces to plan and implement sound water quality measures in the state. Today, these federal, state and local agencies and organizations work cooperatively with farmers and landowners to address nonpoint source pollution in Ohio. Many of these efforts have been directed through cooperatively funded projects, such as 319 water quality projects, hydrologic unit area projects, and Management Systems Evaluation Area projects.
Section 319 of the Clean Water Act provided for the establishment of the Ohio Nonpoint Source Assessment and the Management Plan. A major component of the Management Plan is the implementation of practices to control nonpoint source pollution and to improve the quality of the waters of the state. The implementation component has helped establish watershed control projects supported with federal funds authorized under Section 319, and matched by funds from state and local sources. These projects are commonly referred to as 319 Projects. Since 1989, over 150 Ohio 319 Projects have been initiated. Overall, these projects incorporate educational, technical, and financial assistance to help landowners and farmers address nonpoint source pollution problems. Ohio is one of only a few states that has a coordinated effort to support these 319 projects in evaluating project impact.
In 1989, the USDA initiated the Hydrologic Unit Area (HUA) concept. The goal was to assist farmers and ranchers in voluntarily applying conservation practices to help achieve state water quality goals without experiencing economic hardship. The implementation of this concept was in response to the President's Water Quality Initiative. Nationally, the HUA program emphasized educational, technical, and financial assistance in those hydrologic units where agricultural activities significantly contributed to water quality problems. In most cases, the hydrologic units that were believed to have impaired water quality from agricultural sources were those identified by a state's nonpoint source assessment process, through the provisions of Section 319 of the Clean Water Act. Two USDA agencies, the Natural Resources Conservation Service (NRCS) and the Extension arm of the Cooperative State Research, Education, and Extension Service (CSREES), were given joint leadership responsibility in implementing the program. Nationally, 37 HUA projects were approved in 1990, which includes Ohio's Indian Lake Watershed; and 37 HUAs were approved in 1991, including Ohio's Big Darby Creek Watershed. In Ohio, the major cooperating state, federal, and local agencies include: Ohio State University Extension, Ohio EPA, ODNR, NRCS, the USDA Consolidated Farm Services Agency (CFSA), and the local Soil and Water Conservation Districts.
A direct result of the President's Water Quality Initiative was the establishment of comprehensive research and extension projects in the midwest US. In 1990, Management Systems Evaluation Area (MSEA) projects were established by the USDA and land grant institutions in Iowa, Minnesota (cooperatively with Wisconsin, North and South Dakota), Missouri, Nebraska, and Ohio, cooperatively with the USGS, the USEPA, and other state and federal agencies. The current regional program is composed of coordinated research, education and extension activities that support the evaluation, development and management of agricultural systems to meet the Nation's food supply needs while enhancing water resources and the environment. Current activities of the Ohio MSEA are focused on both ground- and surface-water resources in the Scioto River, Maumee River, and Sandusky River watersheds, with research at the plot, field and watershed scales. The Ohio MSEA incorporates research and extension programs at over 15 1ocations in the state, including The Ohio State University's and USDA ARS's cooperative water table management programs. In 1994 and 1995, MSEA sites were established in Indiana, Mississippi, and North Carolina, and an additional site in Ohio.
A Primer on Nonpoint Pollution. 1985. G. Chester and L. J. Schperow. J. Soil and Water Conser. 40(1):9-13.
Agricultural Best Management Practices. 1991. L. C. Brown, K. M. Boone, S. Nokes and A. Ward. AEX 461. Ohio State University Extension.
Agricultural Best Management Systems. 1990. T. J. Logan. J. Soil and Water Conser. 45(2):46-51.
Best Management Practices for Preventing Contamination of Ohio's Ground and Surface Waters. 1991. Department of Agronomy. Bulletin 818. Ohio State University Extension.
County Water Resources. 1991-1996. Fact sheet series on county specific water resources. Ohio State University Extension. (Over 50 counties completed; contact your Ohio county office of Ohio State University Extension for fact sheet availability).
Crop Production Alternatives. 1990. Department of Agronomy. Bulletin 812. Ohio State University Extension.
Drainage and Water Quality in the Great Lakes and Cornbelt States. 1995. N. R. Fausey, L. C. Brown, H. W. Belcher and R. S. Kanwar. ASCE J. Irrig. and Drain. Engr. 121(4):283-288.
Ground- and Surface-Water Terminology. 1994. L. C. Brown and L. P. Black. AEX 460. Ohio State University Extension.
Impact of Erosion and Conservation in Ohio. 1989. USDA Soil Conservation Service, Ohio State Office.
Nitrogen and the Hydrologic Cycle. 1996. L. C. Brown and J. W. Johnson. AEX 464. Ohio State University Extension.
Ohio's Hydrologic Cycle. 1994. L. C. Brown. AEX 461. Ohio State University Extension.
Ohio Nonpoint Source Management Program. 1993. Ohio Department of Natural Resources. Fountain Square, Columbus, OH 43224.
Ohio Water Resource Inventory Volume 1: Summary, Status, and Trends. 1992. Ohio Environmental Protection Agency. Columbus, OH 43266-0149.
Resource Conservation Glossary. 1982. Soil Conservation Society of America.
State of Ohio Nonpoint Source Assessment: Volume 1. State Overview. 1990. Ohio Environmental Protection Agency. Columbus, OH 43266-0149.
Understanding Ohio's Surface Water Quality Standards. 1994. Ohio Environmental Protection Agency. Columbus, OH 432660149.
This publication was originally produced in 1992 through the Indian Lake Hydrologic Unit Area Project, supported, in part, by the USDA Extension Service, Grant No. 90-EHUA-1-0020, in cooperation with the Department of Agricultural Engineering and Ohio State University Extension. The following persons reviewed the original material: Karen Mancl (OSU); Larry Antosch (Ohio EPA); Jill Deibel and Jerry Wager (ODNR); Norman R. Fausey (USDA Agricultural Research Service); and Dick Swisshelm and Kathleen Sarver (USGS). The production of the 1996 revision was supported, in part, by the Overholt Drainage Education and Research Program, the Department of Food, Agricultural, and Biological Engineering, Ohio State University Extension, the Ohio Management Systems Evaluation Area project (Ohio MSEA), USDA-CSREES Grant No.94-EWQI-I-9057, and the Water Quality Projects Evaluation Workshops project funded through the Ohio Nonpoint Source Program under Section 319 of the Clean Water Act.
A special thanks to Kim Wintringham and Mary A. Hoffelt, Section of Communications and 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