Number 49 September 1991
Several Rural Clean Water Program (RCWP) project 10-year reports have been received. In order to share the valuable experience and lessons learned by project personnel with as wide an audience as possible, summaries of several of these reports will be highlighted in NWQEP NOTES, with an emphasis on recommendations that may be of interest and assistance to staff and participants involved in existing and future NPS control projects.
Featured in this issue are insights offered by the St. Albans Bay (Vermont) Watershed RCWP prepared by the Vermont RCWP Coordinating Committee. The Vermont RCWP was one of five RCWP projects that received funding for a Comprehensive Monitoring and Evaluation (CM&E) program as part of RCWP project activities.
Don Meals
School of Natural Resources, University of Vermont
St. Albans Bay on Lake Champlain has been subject to increasing rates of eutrophication due to excessive phosphorus (P) loads from both point and nonpoint sources. U.S. EPA and the State of Vermont have upgraded sewage treatment plant discharges which originally represented about 48% of the P load to the Bay. In 1990, nonpoint sources contributed over 90% of the total P loading to St. Albans Bay. The purpose of the RCWP project was to address the other significant source of P to St. Albans Bay: agricultural nonpoint source pollution. Major sources of agricultural nonpoint source pollution were improper animal waste and fertilizer management, milkhouse and barnyard wastes, and cropland erosion.
The primary goals of the project were to improve water quality and restore beneficial uses in the Bay through treatment of 75% of watershed critical areas. The principal goal of the CM&E program was to evaluate the effects of the land treatment program on water quality. Land treatment goals were achieved: at the end of the project, 61 of 102 watershed farms had signed RCWP contracts. These contracts covered 74% of critical acres, 79% of animal units, and 80% of total manure P loads.
Overall project administration and land treatment cost-sharing was provided by USDA-ASCS, technical assistance was provided by USDA-SCS, and CM&E was conducted by the University of Vermont Water Resources Research Center. Project coordination was conducted by a Project Advisory Council with members from all participating agencies. This group met quarterly throughout the project and was vital to the success of the program.
The most widely used BMPs were animal waste management and cropland protection.
The complex CM&E strategy for the watershed worked well. St. Albans Bay and major watershed tributaries were intensively monitored for physical, chemical, and biological parameters, providing a data base for long-term trend assessment. Short-term studies yielded critical insights on specific problem areas. Intensive land use/agricultural activity monitoring provided data on cropping and waste management needed to help evaluate relationships between land use and water quality.
Don Meals, Research Associate
Vermont Water Resources and Lake Studies Center
George D.
Aiken Center
The University of Vermont
Burlington, VT 05405-0088
Tel: 802-656-4057
J.P. Zublena, Department of Soil Science
J.C. Barker, Department of Biological and Agricultural Engineering
North Carolina State University
North Carolina is one of the leading states in animal production. Current trends in this industry are towards production consolidation and intensification. These efforts, while being sound from an economic and management perspective, often ignore the potential environmental impact that can ensue from increased generation of animal manures. The nutrient assessment project was initiated to: 1) assess current generation of manure by county, 2) determine the amount of nutrients from manure that could be recovered and made available to agronomic crops, 3) determine the quantity of nutrients required in each county, 4) determine the amount of nutrients purchased in each county, 5) calculate the percent of agronomic crop nutrients that could be supplied by animal manure, and 6) determine the nutrient balance in each county after animal manure and purchased nutrients are considered. Maps showing the distribution of animal types across the state were also generated.
In 1989, 20.7 million tons of animal manure were generated in North Carolina. Because many animals are not confined, only 52% of the manure can be collected for use as a nutrient source or for other purposes. Manures in 1989 contained the equivalent of 158,000 tons of nitrogen (N), 108,000 tons of phosphorus (P2O5), and 101,000 tons of potassium (K2O). Quantities of other nutrients were also measured. Some of these nutrients are not released from manure during the first year after land-application, while others are lost in storage or in the field due to volatilization, leaching, or de-nitrification. We estimated that only 18.5% (29,227 tons/yr) of the N, 37.6% (40,653 tons/yr) of the P2O5, and 25.6% (25,870 tons/yr) of the K2O were actually available for plant usage. When considering on a statewide basis the nutrient requirements of agronomic crops, including pasture, grown in the state and the plant-available nutrients from manures, 12% of N, 44% of P2O5, and 28% of K2O requirements can be met with manures. At the county level, there is enough manure to provide 100% or more of the nutrient requirements for all agronomic crops except legumes and pasture in three counties for N, 19 counties for P2O5 (see maps), and eight counties for K2O.
Commercial fertilizer purchases were also considered in assessing county nutrient balances. While these data may reflect a bias because fertilizers purchased in one county may be used in another county, the data still warrant consideration. Based on this input, approximately 35% of the counties had surplus quantities of N, P2O5, and K2O, utilizing a crop base excluding legumes and pastures.
This assessment is being used by the North Carolina Cooperative Extension Service to focus and network educational efforts on animal waste management where there is the greatest need. Agents in counties where quantities of manure can supply a significant portion of crop nutrient needs are being encouraged to include manure management into their plans of work and to share this information with their county commissioners and advisory boards.
In addition, agents are being encouraged to use the animal distribution maps to initiate discussions with livestock companies on the need to consider dispersing animal operations to prevent "clustering" of animal units that might serve as point sources of water contamination if they exceed the crop nutrient needs of the area.
Meetings with the fertilizer industry were initiated to discuss the potential impact of these findings on their sales and to explore opportunities for incorporating organic sources into existing fertilizer operations.
Agent training in animal waste management has been conducted to familiarize agents with the nutrient assessment; the process of manure decomposition and its consequence on nutrient release; and nutrient management and how it affects water quality.
Two Soil Science fact sheets have been published to aid extension agents in working with producers to show them how to calculate manure applications based on their crop nutrient needs (Poultry Manure as a Fertilizer Source and Swine Manure as a Fertilizer Source). Slide sets on the nutrient assessment have also been developed on a state and district basis for specialist and agent use.
For further information about the project, fact sheets (single copies are free), or slide show, contact Joe Zublena (Dept. of Soil Science, Box 7619, NCSU, Raleigh, NC 27695, Tel: 919/515-3285) or Jim Barker (Dept. Biological and Agricultural Engineering, Box 7625, NCSU, Raleigh, NC 27695, Tel: 919/515-2675). For bulk orders of fact sheets: Agricultural Communications, 318 Ricks Hall, Box 7603, NCSU, Raleigh, NC 27695.
U.S. EPA, USDA-CES and USDA-SCS recently announced the launching of a national version of the Farm*A*Syst Program. The program is designed to assist farmers in assessing potential agricultural sources of groundwater pollution related to farmstead activities and structures. Farmsteads include the farm buildings and land around them where many farm activities are concentrated. In addition, fertilizer, pesticides, and livestock wastes that are applied to cropland are handled and/or temporarily stored at farmsteads. Other potentially-polluting substances handled at many farmsteads include petroleum products, solvents, and other non-crop chemicals. The concentration of farmstead substances can, if not properly handled, contaminate ground water with significant amounts of nutrients, animal wastes, bacteria, pesticides, and other substances.
A pilot Farm*A*Syst program was initiated in 1990 by the Universities of Wisconsin and Minnesota and U.S. EPA in four counties in Wisconsin and Minnesota. Other states already using Farm*A*Syst in USDA hydrologic unit or demonstration projects, Clean Water Act Section 319 projects, or other watershed projects to manage nonpoint source pollution include Iowa, Missouri, Indiana, Michigan, Texas, Oklahoma, and Arkansas.
The Farm*A*Syst program was developed by the Universities of Wisconsin and Minnesota and U.S. EPA. The system involves farm operators in a voluntary on-site analysis to identify pollution risks associated with farmstead activities. The system is designed to provide accurate, site-specific information and recommendations for practices that may be affecting groundwater.
A series of 10 worksheets is used by a farmer to evaluate the risk of farmstead activities and structures for causing contamination of well water. A separate evaluation worksheet helps farmers assess specific soil and geologic features of their land and how these factors affect ground water pollution potential. Then an overall evaluation sheet combines the findings from the site evaluation and the assessments to develop a relative risk rating and action plan for the particular farmstead. Educational materials provide information on local sources of technical assistance and emphasize the cost-effectiveness of taking corrective or preventative measures.
The assessment can be conducted individually or in group educational sessions. The latter usually involves local professionals and agency technical staff who can also help farm operators identify appropriate corrective actions.
Farm*A*Syst examines a wide range of potential contaminants and remedies in a comprehensive, easy manner. Through the Farm*A*Syst program farm operators can accurately assess their farmsteads and take decisive action to preserve the quality of their drinking water.
For more information, contact Gary Jackson or Sue Jones, Environmental Resources Center, Univ. Wisconsin, Madison, WI 53706-1562, Tel: (608)262-0024.
Dan Line joined the Water Quality Group as an Extension Specialist on September 3, 1991. He joins us from the USDA Agricultural Research Service (ARS) in Oxford, Mississippi, where he was employed as a research hydraulic engineer for the past five years. Dan's work at ARS has focused on research on cropland erosion and sedimentation, conservation practices, and sediment yield models. Our newest specialist recieved both his Bachelor of Science and Master of Science in Agricultural Engineering at Pennsylvania State University. Dan's work at the NCSU Water Quality Group will include verification and calibration of a chemical simulation model to estimate pollutant loadings using watershed data in a geographic information system as part of the Phase II Gaston County, North Carolina project. He will also coordinate on-site evaluations of several of the RCWP projects and provide technical assistance for monitoring and project planning in association with the Group's Section 319 watershed grant. Welcome to the Group, Dan!
Jean Spooner
NCSU Water Quality Group
Water quality monitoring is the only way to document statistically the effectiveness of a management strategy for restoring impaired water uses using an experimental design (Brichford et al., in press). In addition, monitoring results serve as a basis for further refinement of the development of a management strategy (Ward et al., 1986). Policies for nonpoint source (NPS) pollution control depend largely on information gained from scientific investigations. Monitoring can provide: 1) definitive assessments for NPS impacts across the nation; 2) identification and quantification of pollutant(s) and pollutant sources; 3) identification of impaired water resources; 4) assessment of the water quality impact of NPS control efforts; and 5) identification of water resources capable of improvements if NPS control efforts were implemented on a watershed basis.
Under the Clean Water Act, the states and interstate agencies, in cooperation with U.S. EPA, perform water quality monitoring. These monitoring systems and others performed by individual agencies are used to establish and revise water quality standards, calculate total maximum daily loads, assess compliance with permits, evaluate the effectiveness of control measures, establish baseline water quality data, locate problem areas, and report on conditions and trends in ambient waters (U.S. EPA, 1987a; 1987b).
Baseline water quality and subsequent trend detection is essential to assess the water quality impact of NPS control programs or any other change in land and water use activities. Therefore, there is much interest in monitoring techniques to assess the magnitude of the water quality impairment and impacts of NPS control efforts. For example, Rural Clean Water Program (RCWP) and Model Implementation Program (MIP) have devoted considerable resources to developing and evaluating appropriate monitoring designs that document water quality changes due to best management practice (BMP) implementation on the watershed level. New state and federal NPS control programs (e.g., Section 319 National Monitoring Program, USDA Demonstration and Hydrologic Unit Projects) are currently evaluating and implementing water quality and land use monitoring designs.
Monitoring agricultural NPS pollution may require a monitoring design with different characteristics compared to monitoring point sources. The location of monitoring stations and the frequency and duration of sampling may be different. Point sources may be easier to monitor because location and sources can be identified more precisely than nonpoint sources. Nonpoint sources are more difficult to identify and quantify due to spatial inputs, and more monitoring stations may be needed because sources are spatially diffuse instead of originating at a defined point.
Variability in water quality data can be a significant problem in evaluating both point and nonpoint sources. Point sources can vary with industrial processes, time of day, and day of the week. Nonpoint sources usually exhibit high variability due to large fluctuations in hydrologic and meteorologic processes. With nonpoint sources, high variability in pollutant concentrations occur within storms, between storms, and between seasons and years. Watershed size is another factor introducing variability into NPS monitoring data (Baker et al., 1985).
For point sources, a short duration of monitoring above and below the source may be sufficient to determine the magnitude of a water quality problem and evaluate permit compliance. Also, point source effluent is commonly monitored directly to meet permit conditions. With nonpoint sources, longer periods of monitoring (more than a year) may be required to determine the magnitude of the problem. This is especially true at the watershed level where system variability is high. Trend detection may require a far longer time frame. The time frame required for trend detection is a function of the monitoring network design and unexplained variability in the water quality monitoring data.
The frequency of both NPS and point source monitoring is determined by the objective of the water quality monitoring program. For example, concentration measurements for trend analyses or assessment of water quality standards violations require fewer samples than load calculations.
The type and number of variables measured with agricultural NPS monitoring are a function of the source and water use impairment. The variables of concern may be sediment, phosphorus, nitrogen, fecal coliform, BOD, pesticides, or the degradation products of known pesticides. Clear definition of the impairments and sources will allow for efficient monitoring of only those pollutants of primary concern. Except for pesticides, most agricultural NPS pollutants are naturally occurring and only harmful in excess. In fact, most are required in some quantities to support aquatic biota.
Point source pollutants are also a function of the source. If the source is well defined (e.g., a known chemical or processing plant), the number of variables that must be monitored may be small. However, many point sources such as sewage treatment plant effluent may contain many pollutants, some of which are unknown, and the number of pollutants that must be monitored may therefore be large. In addition, many of the pollutants from point sources may be toxic to the natural ecosystem.
The relationship of pollutant concentration and streamflow or storm discharge is usually positive with nonpoint sources. When streamflow increases, pollutant concentrations increase. During runoff events, the NPS peak concentrations of sediment, pesticides, and nutrients are associated with the peak or near the peak of the storm hydrograph (Baker et al., 1985). However, with point sources, the concentrations tend to decrease with increasing streamflow due to dilution of the point source input (Baker, 1988; Eheart, 1988); hence the familiar phrase developed for point source control, "dilution is the solution to pollution." Higher streamflows were associated with lower concentrations in a study using 10 years of water quality data from Michigan streams near urban areas (Holtschlag, 1987). Eheart (1988) confirmed with modeling of point source loadings that water quality as measured by BOD (biological oxygen demand) or dissolved oxygen will usually be worst at low streamflow. However, he also modeled cases where this phenomenon was reversed. Eheart (1988) demonstrated that these variables may increase with increasing streamflow if the stream is highly polluted from multiple point discharges due to a decreased decay coefficient of the pollutants and decreased re-aeration coefficient with increasing streamflow. Eheart (1988) did acknowledge that NPS pollutants tend to increase in concentration with increasing flow, but only considered point sources in his model.
The hydrograph-concentration relationship for NPS pollution is further complicated by runoff and transport mechanisms which vary by pollutant and season. This results in flow versus concentration patterns for nonpoint sources that are not equivalent for each pollutant. The peak concentrations of particulate and soluble pollutants occur during different parts of the hydrograph because hydrograph-concentration response is not only a function of the streamflow, but also of runoff and transport mechanisms (Baker et al., 1985). In contrast, point source pollutant concentrations usually vary similarly for each pollutant with the changes in discharge because dilution is the primary determinant of concentration.
In-stream processes affect the fate and transport of both NPS and point source pollutants. Water resources tend toward quasi-equilibriums maintained by in-stream processes. For example, decreasing sediment delivery to a stream using NPS controls may not decrease the sediment concentration measured at a downstream monitoring station. Streamflow may pick up sediment deposited earlier on the streambed or may scour the banks. Pollutants may be assimilated by animals or plants, adsorbed to soil, or degraded before reaching the monitoring station en route from the source. The influence of in-stream processes increases as distance from the source of the pollutant to the monitoring station increases. Generally, nonpoint sources are monitored farther from their sources of origin than point sources.
The response time or lag time of NPS impacts measured in receiving waters is not constant and usually involves a longer lag time compared to point sources. Lag time refers to the time elapsed from pollutant origination and detection of the pollutant at the monitoring station. Lag time is a function of the distance to the monitored water resource (e.g., tributary, lake), magnitude of the source, volume of drainage or runoff, and soil and land use conditions before an runoff event. The mechanisms of transport, buffering effect, and inertia in the system tend to cause a slower response in water resources that are distant from pollutant sources. This problem is more prominent with nonpoint sources than with point sources, where measurement near the source is usually more feasible.
In summary, the different process and transport mechanisms that distinguish point from nonpoint sources may require different monitoring designs. NPS control assessment requires uniform sampling strategies that account for influences from storm events and seasonal factors and that avoid bias. Specifically, NPS control assessment requires fixed stations, monitoring for long periods, and recording related data such as hydrologic, meteorologic, land use activities, and demographic data (U.S. EPA, 1987b).
Baker, D.B. 1988. Sediment, Nutrient, and Pesticide Transport in Selected Lower Great Lakes Tributaries. EPA-905/4-88-001. Great Lakes National Program Office Report No. 1. Chicago, Illinois 60604.
Baker, D.B., K.A. Krieger, R.P. Richards, and J.W. Kramer. 1985. Effects of intensive agricultural land use on regional water quality in northwestern Ohio. p. 201-207. In: Perspectives on Nonpoint Source Pollution. EPA 440/5-85-001.
Brichford, S.L., J. Spooner, and S.W. Coffey. In press. The role of water quality monitoring in a NPS control program. In: National Nonpoint Conference: The Water Quality Act - Making Nonpoint Programs Work. National Association of Conservation Districts (NACD), League City, Texas.
Eheart, J.W. 1988. Effects of streamflow variation on critical water quality for multiple discharges of decaying pollutants, Water Resources Research 24(1):1-8.
Holtschlag, D.J. 1987. Changes in Water Quality of Michigan Streams near Urban Areas, 1973-1984. U.S. Geological Survey. Water-Resources Investigations Report 87-4035. Michigan Department of Natural Resources, Surface Water Quality Division, Lansing, Michigan.
U.S. EPA. 1987a. National Water Quality Inventory: 1986 Report to Congress. EPA- 440/4-87-008. Office of Water, U.S. EPA, Washington, D.C.
U.S. EPA. 1987b. Review of a Framework for Improving Surface Water Monitoring Support for Decision-making: Report of the Environmental Effects, Transport and Fate Committee. SAB-EETFC-88-006. Office of the Administrator, Science Advisory Board, U.S. EPA, Washington, D.C. 20460.
Ward, R.C., J.C. Loftis, and G.B. McBride. 1986. The "data-rich but information-poor" syndrome in water quality monitoring, Environmental Management 10(3):291-297.
Note: The author would like to thank Dr. Jack Clausen, of the Department of Natural Resources, University of Connecticut at Storrs, for his contribution to this article through valuable discussions regarding water quality monitoring programs for point and nonpoint sources.
The Field Manual is designed for professionals involved in the implementation of erosion control practices. This portable manual describes commonly used and accepted practices for erosion control from vegetative seeding to construction of sedimentation traps and large structures. It is fully illustrated with photographs and technical drawings and lists construction methods, common trouble points, and required maintenance.
Copies can be ordered ($20) from the North Carolina Department of Environment, Health and Natural Resources, Land Quality Section, P.O. Box 27687, Raleigh, NC 27611.
Agricultural BMPs Applicable to Virginia
Heatwole, C., T. Dillaha, and S. Mostaghimi. 1991. Agricultural BMPs Applicable to Virginia. Bulletin 169, Virginia Water Resources Research Center, Virginia Polytechnic Institute and State University, Blacksburg, VA.
This report summarizes findings from the literature on impacts and effectiveness of BMPs applicable to agriculture in Virginia. Characteristics of BMPs, techniques for assessing effectiveness, social and economic factors affecting implementation, and research needs are discussed.
Copies available from Publications Service, Virginia Water Resources Research Center, 617 N. Main St., Blacksburg, VA, Tel: 703-231-5624 (prepayment required: out-of-state $10; in-state, first copy free; additional copies $10).
I welcome your views, findings, information, and suggestions for articles. Please feel free to contact me.
Judith A. Gale, Editor
Water Quality Extension Specialist
North Carolina State University Water Quality Group
Campus Box 7637
North Carolina State University
Raleigh, NC 27695
Tel: 919-515-3723
Fax: 919-515-7448
email: notes_editor@ncsu.edu