Background

The aim of the program is to provide farmers, ranchers, and foresters with the knowledge, technical means, and financial assistance to respond independently and voluntarily in addressing farm-related environmental concerns and related state water quality requirements.

The Initiative's Water Quality Program Plan requires a program evaluation by the Education, Technical Assistance, and Financial Assistance Committee (ET&FA) of the USDA Working Group on Water Quality (co-chaired by the Agricultural Stabilization and Conservation Service, Extension Service, and Soil Conservation Service).

Interim Assessment: Physical Impacts of Selected USDA Water Quality Projects (USDA, 1993b), published in October, 1993, by the Soil Conservation Service in cooperation with Texas A&M University and the University of Vermont, is one of four components of an ET&FA evaluation strategy to document water quality progress. The other ET&FA evaluation components are: 1) an assessment of the organization and initial implementation of the Demonstration projects approved in 1990 (Rockwell, Hay, and Buck, 1991); 2) an ongoing four-year study of producer adoption of best management practices in eight Demonstration projects; and 3) an analysis of cost-effectiveness to be conducted by the Economic Research Service.

The interim report documents the extent to which 16 USDA water quality projects (eight Hydrologic Unit Area (HUA) and eight Demonstration (DP) projects) are improving or protecting water quality by reducing agricultural nonpoint source pollutants. The 16 projects were chosen to represent the major agricultural nonpoint source problems found in 90 ongoing USDA water quality projects.

The projects evaluated fall into two groups classified by impaired water body, nonpoint source pollutant, and agriculture type.

Group I includes eight projects primarily concerned with surface waters impaired by sediment, nutrients, animal wastes, or bacteria generated by livestock production or non-irrigated cropland. DPs in Maryland, North Carolina, and Wisconsin, and HUAs in Alabama, Indiana, Michigan, New York, and Utah are in Group I. Eutrophication, sedimentation, and oxygen demand have resulted in impairments of water bodies for fisheries, drinking water, recreation, and aesthetics. Common agricultural management deficiencies include lack of erosion control on cropland and streambanks, sediment delivery from cropland, excessive fertilizer application, poor animal waste management, and inadequate animal carcass disposal practices. The dominant goals are reducing nutrient and sediment loads to receiving waters or reducing pollutant concentrations in receiving waters.

The six Group II projects focus primarily on contamination of shallow ground water and associated surface waters with nitrate and pesticides leaching from irrigated cropland. DPs in Florida, Minnesota, and Nebraska, and HUAs in Delaware, Illinois, and Oregon are in this group. Nitrate concentrations exceeding USEPA's Maximum Contaminant Level in drinking water, excessive nitrogen loading to surface waters in base flow, and detections of corn herbicides and other pesticides in drinking water are typical of the water quality impairments in this group of projects. Common agricultural management deficiencies include excessive nitrogen applications, cultivation on extremely sandy soils, poor irrigation management, and high pesticide application rates. Two of the projects direct their efforts toward threatened, rather than currently impaired, aquifers. The main goals of Group II projects are reducing nitrate and pesticide levels in ground water.

Two DPs do not easily fit into either Group I or Group II. The Texas DP focuses on a closely interconnected surface water - ground water system. The major issues relate to sediment movement from rangeland and nutrient and pesticide movement from cropland, pastureland, and rangeland. The project is concerned with the quality and quantity of water for recharge of the Edwards aquifer as well as quantity and efficiency of water use. The California DP is concerned with reducing transmission of herbicide residues used in irrigated rice production to the Sacramento River system. Irrigation tailwater management is the primary agricultural management issue.

Physical impacts of the 16 projects were evaluated on the basis of three indicators of significant progress: 1) implementation of improved management practices and agrichemical management, 2) simulated reductions in pollutant loadings, and 3) monitored water quality changes.

Results

Nitrogen pollution reduction practices have been implemented in all 16 projects. Eleven projects applied pesticide management and erosion or sediment control practices. The 16 projects achieved sizable reductions in applied nutrient amounts -- 6.7 million pounds of nitrogen and 4 million pounds of phosphorus. The full significance of these reductions is limited by insufficient data on pre-project applications.

While several projects showed reduction in pesticide use, evaluation of changes in pesticide use has proved far more complex than assessment of nutrient use. The type, rate, and method of application can vary greatly from year to year as the result of changes in crop, weather, and pest pressure. Improvements in timing of application can reduce environmental damage even though the total amount of pesticides applied has not decreased. Several project teams promoted changes to less toxic pesticides, improved timing and method of application, and targeted assistance to producers farming soils with potentially high leaching and/or runoff.

The field-scale models used most frequently were EPIC and GLEAMS; AGNPS was the most used watershed-scale model.

Three projects were already able to document a solid link between water quality objectives and simulated edge-of-field loading changes. Six others made significant progress in documenting such linkages. Intensive use of these and other models has provided model developers with valuable feedback on how the models are being used and how they can be improved.

Although water quality monitoring was not a project requirement, 14 of the 16 projects include some type of monitoring. However, in many projects, monitoring networks were established after the USDA projects had already been planned (or even, in some cases, after practice implementation had already begun). Often these monitoring programs have been designed based on objectives other than objectives of the USDA projects.

Except for three or four projects, it will be difficult to link practice installation to measured improvements in water quality. The primary reasons for this difficulty are insufficient attention during project formulation to the role, design, and execution of an integrated monitoring network; lack of emphasis on annual tracking of improvements in agrichemical use and land management; the dynamics of hydrologic cycles and weather; and short project lives (five years).

Interim Recommendations

• Project planners need to establish well-documented, clear, and quantifiable objectives and likewise establish unbiased procedures to measure pre-project (either baseline or trend) and post-project levels for each objective, as well as changes during project implementation.

• A successful water quality project is one that is making cost-effective progress toward its clearly stated objectives.

• Technical guidance and training should be provided to project staff in preferred, cost-effective methods for tracking land treatment and agrichemical management.

• Technical guidance and training should be developed and provided to project staff in the use of physical-process simulation models, in water quality monitoring (on physical, chemical, and biological variables), and how these technologies should be used to complement one another.

• Acceptable objectives for water quality projects, in terms of physical impacts, should fall into one of three categories: 1) improvements in land treatment and agrichemical management; 2) reduction in pollutant losses from crop or livestock enterprises (this could also be stated as reduction in potential pollutant loadings to water); or 3) improvement in specific water quality variables.

• Simulated or monitored values for variables in the first two categories (see bullet above) (such as tons of animal waste managed properly or nitrate leaching past the bottom of the crop's root zone) are critical measures of direct progress toward land management improvement objectives. However, they should be considered only as indirect measures of water quality protection or improvement since they do not measure actual receiving water quality. Only monitored values for variables in the third category (see bullet above) (such as nitrate concentration in water or dissolved oxygen levels) should be considered direct measures of progress toward water quality protection or improvement objectives.

• For tracking improvements in land treatment and agrichemical management, serious consideration should be given to development and use of unbiased statistical methods that would allow: 1) estimating actual agrichemical application rates and acreage under improved management and taking account of units of practices installed; 2) ascertaining whether producers who have received assistance to install annual practices, such as nutrient management, continue in subsequent years to implement those practices as designed; and 3) determining the degree of independent adoption by producers of practices demonstrated by project staff.

• Emphasis should be given to developing staff capabilities to choose appropriate field- and watershed-scale simulation models, acquire reliable data at least cost, and use selected models properly, including output interpretation and sensitivity analysis.

• Proper use of models includes their use in the project planning process to help identify critical pollutant source areas, identify the nature of the pollutant problem, design water quality monitoring, and determine potential (and relative) effects of alternative management systems on pollutant loadings.

• Agencies should continue to place a high priority on the development and training in the use of screening tools for nitrogen, phosphorus, and sediment to assist in identifying potential pollutant source areas and areas to target management improvements. Linkage to total maximum daily load (TMDL) tools could be useful.

• Water quality monitoring and evaluation must be an integral part of project planning, design, operation reporting, and evaluation.

• Water quality data should be used, to the extent possible, to help target land treatment and assess interim progress.

• Project staffs should participate in water quality monitoring activities and in data management and interpretation to the fullest extent possible.

• Project planners and staffs should be trained in basic concepts of monitoring and evaluation. This may require ET&FA to develop a training curriculum that includes monitoring for its water quality staffs.

For Further Information

John Sutton
Soil Conservation Service, U.S. Department of Agriculture
Room 6808-S, P.O. Box 2890, Washington, DC 20013
Fax: (202) 720-9030

References

USDA. 1993a. Water Quality: A Report of Progress. Working Group on Water Quality, U.S. Department of Agriculture, Washington, DC, 14p.

USDA. 1993b. Interim Assessment: Physical Impacts of Selected USDA Water Quality Projects. U.S. Department of Agriculture, Soil Conservation Service in cooperation with Texas A&M University and the University of Vermont, Washington, DC,October 1993, 26p.

This report presents the results of a study to determine the efficiency of a wet detention pond in reducing pollutants found in stormwater runoff. Also investigated were: hydrologic responses to rainfall, ground water - pond interactions, constituent input from rainfall, relationships between constituents, and the dynamics of constituent concentrations over the hydrograph. Discharge water quality was also compared to State of Florida Class III water quality standards. The study site is a small (0.32 acres) shallow wet detention pond built in 1986 that receives runoff from a basin of 6.3 acres draining a light commercial development.

Kehoe, M.J. 1993. Water-Quality Survey of Twenty-Four Stormwater Wet-Detention Ponds (Final Report). Southwest Florida Water Management District, Brooksville, FL, 84p plus appendices.

During 1988 and 1989, SWFWMD conducted a water quality survey of 24 stormwater wet-detention ponds in the Tampa Bay region. All of the ponds had been permitted by SWFWMD. The objectives of the survey were: 1) to provide regional, baseline water quality data for urban stormwater wet-detention ponds; 2) to document whether the water quality of potential effluents from wet-detention ponds met state water quality standards, providing insight concerning effectiveness of stormwater management rules used by SWFWMD; and 3) to explore relationships among physical/chemical (water quality) variables, water level variables, and pond dimension variables. The author describes the design, implementation, and results of the survey; discusses the problems encountered; and makes recommendations for future stormwater surveys and projects.

Southwest Florida Water Management District. 1993. Proceedings of the 3rd Biennial Stormwater Research Conference, October 7 & 8, 1993, Tampa, Florida. Southwest Florida Water Management District, Brooksville, FL, 389p.

This proceedings presents 31 papers (and seven abstracts) from the third in a continuing series of symposia sponsored by SWFWMD and designed to present the engineers, scientists, and regulators working in the field of stormwater management with the most current ideas and data available so that more efficient and cost-effective treatment of stormwater can be realized. Conference sessions addressed: 1) watershed management plans/NPDES; 2) modeling; 3) best management practices, rehabilitations, and retrofits; and 4) stormwater quality processes.

In addition to the three publications described above, reprints of articles on the following topics are also available from SWFWMD:

• Significant Conclusions Documented from Stormwater Research (1993)

• The Effectiveness of Permitted Stormwater Systems for Water Quality Control (1993)

• A Native Herbaceous Marsh Used for Stormwater Treatment (1993)

• An Isolated Wetland Used for Stormwater Treatment (1993)

A step-by-step model for integrated coastal management, Managing Wastewater in Coastal Urban Areas, is available from the National Research Council. The publication addresses basic principles and methods aimed at maintaining ecological processes and meeting human needs for goods and services. Phases of integrated coastal management are examined, including setting of goals based on community input, definition of the geographic scope of the management program, and monitoring. Potential barriers and how they may be overcome are also discussed.

The report may be ordered from the National Academy Press, 2101 Constitution Ave., NW, Box 285, Washington, DC 20055, Tel: 800-624-6242 or 202-334-3313, fax: 202-334-2451. The cost is $49.95 per copy, plus shipping charges of $4 for one copy (add $.50 for each additional copy).

The latest in a series of National Water Summaries published by the U.S. Geological Survey (USGS), this document uses a nationally consistent data base and methods of statistical analysis to document stream water quality in the United States, Puerto Rico, and the Western Pacific Islands. The report is intended to complement existing federal-state water quality reporting to Congress as required by the Clean Water Act. As a basis for the report, USGS created a data base of water quality data from about 2,900 stream water quality monitoring stations in the United States.

An 80-page section entitled Hydrologic Perspectives on Water Issues includes discussions of: 1) factors affecting stream water quality; 2) statistical analysis of water quality data; 3) assuring water quality data reliability; 4) stream water quality in the coterminous United States (status and trends of selected indicators during the 1980s); and 5) nationwide water quality reporting to Congress as required under Section 305(b) of the Clean Water Act. Long-term (1905-80) water quality trends are described for four drainage basins:

• The Great Lakes - Upper St. Lawrence River at and near Ogdensburg, New York and Cornwall, Ontario;

• The Columbia River at and upstream from The Dalles, Oregon;

• The Allegheny River upstream from Pittsburgh, Pennsylvania; and

• The lower Mississippi River at and upstream from New Orleans, Louisiana.

• Overview of stream water quality;

• Discussions of water quality monitoring;

• Description of water quality conditions (statistical summaries of data on concentrations of up to 8 constituents at up to 10 selected monitoring stations during 1987-89);

• Description of trends in concentrations of up to 8 constituents for 10- to 20-year periods ending in 1989;

• Description of water quality management;

• Selected references (state, local, general) on stream water quality; and

• Table and multicolor illustrations showing: selected water quality constituents and their source and environmental significance; land use, physiography, and population; location of selected water quality monitoring stations; water quality conditions of selected streams during 1987-89; and trends in water quality of selected streams as reflected by selected constituents over 10- to 20-year periods ending in 1989.

Copies of a particular state's stream water quality summary may be requested from the USGS district office in the state (district offices are usually located in state capitals).

NWQEP NOTES is issued bimonthly. Subscriptions are free within the United States (contact: Publications Coordinator at the address below or via email at wq_puborder@ncsu.edu). A list of publications on nonpoint source pollution distributed by the NCSU Water Quality Group is included with each hardcopy issue of the newsletter.

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