Number  71		       May  1995		ISSN 1062-9149

Monitoring of both land treatment and water quality is necessary to document the effectiveness of nonpoint source pollution controls in restoring water quality. The Section 319 National Monitoring Program, administered by the U.S. Environmental Protection Agency, is designed to support watershed projects throughout the country that meet a minimum set of project planning, implementation, monitoring, and evaluation requirements. The requirements are designed to lead to successful documentation of project effectiveness with respect to water quality protection or improvement. The National Monitoring Program projects comprise a small subset of nonpoint source control projects funded under Section 319 of the Clean Water Act Amendments of 1987. The following article continues a series describing these projects.

Oak Creek flows through the southern rim of the Colorado Plateau, dropping approximately 2,700 feet from its source along the Mogollon Rim to its convergence with the Verde River. Several gaining reaches contribute to the perennial flow of the creek. Flows vary from a low of less than one cubic feet per second (cfs) to a high snowmelt-contributed flow of over 1800 cfs. The average annual flow within the project area, Oak Creek Canyon, is about 13 cfs. The majority of rainfall occurs during short, intense summer storm events.

The Oak Creek Canyon 319 National Monitoring Program (NMP) project focuses exclusively on a 13-mile steep-walled segment of the creek located in the canyon portion of Oak Creek. This area is characterized by steep canyons and rapid water flows with sharp drops forming waterfalls and deep, cold pools. Oak Creek Canyon is a narrow strip of deep-canyon land extending from the city of Sedona 13 miles northward to the Mogollon Rim. The width of the canyon varies from one to three miles. Although Oak Creek Canyon watershed encompasses 5,833 acres, only 907 acres are considered critical (this is the area located on slopes less than 15%). The major land use of the canyon area is recreational. The U.S. Forest Service and Arizona State Parks have developed campgrounds, parking lots, picnic areas, and scenic views along Scenic Highway, Route 89A. Private homes and businesses account for much of the remaining land use.

The Oak Creek 319 NMP project focuses on the implementation and documentation of integrated best management practice (BMP) systems for three locations: Slide Rock State Park, Pine Flats Campground, and Slide Rock parking lot.

Water quality at Slide Rock State Park, which is used by more than 350,000 swimmers annually, is characterized by large seasonal fecal coliform loads. Runoff from Pine Flats Campground, which accommodates approximately 10,000 campers each season, delivers fecal coliform and excess nutrients to Oak Creek. Runoff from the State Park parking lot, which accommodates 90,000 vehicles each season, drains into Oak Creek.

Best management practices to be implemented at Slide Rock State Park and Pine Flats Campground include enhancing rest room facilities, better litter control, and promotion of visitor compliance with park and campground regulations on facility use, littering, and waste disposal. Practices to be implemented at the parking lot include periodic cleaning and promotion of an aerobic environment in the detention basin (and retrofitting, if needed) and periodic sweeping of the area.

A paired-site upstream/downstream water quality monitoring design will be used to evaluate the effectiveness of BMPs in improving water quality at Slide Rock State Park (treatment site). This portion of the Oak Creek project is referred to as the Water Recreation Project. Grasshopper Point, a managed water recreation area similar to Slide Rock State Park, will serve as the control site. Monitoring will be conducted upstream and downstream of both sites.

A paired-site upstream/downstream water quality monitoring design will also be used for the Pine Flats and Manzanita Campgrounds (Campground Project). Manzanita will serve as the control site, while Pine Flats will serve as the treatment site. Monitoring stations will be upstream/downstream of both campgrounds.

Weekly grab samples will be taken from May through September for seven years in both monitoring programs.

The Slide Rock Parking Lot Project will evaluate the effectiveness of a detention basin designed to limit pollutants from entering the Creek. An event-based BMP-effectiveness monitoring scheme will be used. Automatic samplers, triggered by rainfall and runoff, will be installed at inflow and outflow points of the detention basin. Each sampler will collect first flush and composite periodic samples.

The Oak Creek National Monitoring Project complements several other programs located in the Verde Valley:

• The U.S. Geological Survey has initiated a comprehensive water use/water quality study focusing on the north central Arizona region extending from the City of Phoenix to the Verde Valley.

• The Verde Watershed Watch Program is a 319(h)-funded program run by Northern Arizona University. The program is designed to train students and teachers from seven high schools (located within the river basin) in macroinvertebrate and water chemistry sampling to evaluate the effects of BMP implementation.

• The Arizona Department of Environmental Quality has established the Verde Nonpoint Source Management Zone, a five million-acre watershed which includes the Oak Creek Watershed.

• The Colorado Plateau Biological Survey has established a major riparian study focusing on the Beaver Creek/Montezuma Wells area of the Verde Valley.

1994 to 2001

Pre-Project Water Quality

Biological, nutrient, and vehicular pollutants threaten the water quality of Oak Creek. Oak Creek water quality is impaired by high fecal coliform levels, probably resulting from failing residential septic systems and the high usage of the campgrounds and day-use swimming areas by over 350,000 people during a concentrated period of time (May through September). Excessive nutrients, particularly phosphorus, threaten the water quality of two impoundments below Oak Creek that provide drinking water for the city of Phoenix. Finally, heavy metals, petroleum hydrocarbons, and total organic carbons from the estimated four million vehicles traveling along State Highway 89A each year, and numerous parking lots in the area, drain into Oak Creek during rainstorms and snow melts.

Preliminary data suggest that the Slide Rock Park parking lot detention basin (a large, baffled concrete vault) contributes to, rather than reduces, environmental damage. Approximately four feet of stagnant water remains in the vault at all times. Heavy rainfall cleanses the parking lot of pollutants and flushes pollutants out of the detention basin.

Project Water Quality Objectives

Water Recreation Project Objectives:

• 50% reduction in fecal coliform

• 20% reduction in nutrients, particularly ammonia

• 20% reduction in total organic carbons corresponding with a reduction in biological oxygen demand

• 50% reduction in fecal coliforms

• 20% reduction in nutrients

• 25% reduction of automobile-related pollutants entering Oak Creek

Designated beneficial uses of Oak Creek include full body contact recreation, cold water fishery and wildlife habitat, drinking water, agriculture, and livestock watering. Oak Creek was designated as a Unique Water by the Arizona State Legislature in 1991 on the basis of 1) its popularity and accessibility as a water recreation resource; 2) its aesthetic, cultural, educational, and scientific importance; and 3) its importance as an agricultural and domestic drinking water resource in the Verde Valley. Also contributing to the designation of uniqueness was the susceptibility of Oak Creek Canyon to irreparable or irretrievable loss due to its ecological fragility and location.

The Water Recreation Project is designed to enhance rest room facilities at the Slide Rock swimming area, enforce littering laws to reduce disposal of trash in unauthorized areas, and promote compliance with park regulations.

The nonpoint source control strategy for the Campground Project targets the upstream site of Pine Flats. Best management practices implemented at Pine Flats are designed to reduce pollutants associated with human use of campground facilities. Practices include installation of an enclosed shower for campers, enforcement of a clean zone between the creek and the campground, and promotion of the use of existing rest rooms. Direct contact by park personnel with visitors and the addition of more visible signs will help accomplish these goals.

The BMP strategy for the Slide Rock Parking Lot Project focuses on reducing runoff from the parking lot and parking lot detention basin. The existing detention basin will be cleaned out prior to and after the rainy season. An aerobic environment within the basin will be promoted and street sweeping of the parking lot will occur.

Water quality monitoring stations for Oak Creek Canyon 319 National Monitoring Program project.

Water Quality Monitoring Design

The Water Recreation Project will use a paired-site upstream/downstream monitoring design to document the change in water quality resulting from application of BMPs. Swimming sites at Slide Rock State Park (treatment site) and the Grasshopper Point (control site) will be the paired comparison. Water quality monitoring stations will be located above and below each swimming area. Variables to be measured include fecal coliform, nitrate (NO3), phosphates, total organic carbon, and biological oxygen demand (BOD). Explanatory variables include water temperature, stream velocity and level, number of users, and weekly precipitation.

A paired-site upstream/downstream monitoring design will also be implemented at treatment and control sites in the Campground Project. Variables measured will be fecal coliform, total nitrogen, total phosphates, ammonia, NO3, and ortho-phosphate. Explanatory variables will include pH, water temperature, conductivity, water flow rate, dissolved oxygen, total dissolved solids, and precipitation.

Grab samples will be collected weekly on Saturday afternoons from May 15 through September 15 and monthly from November through April (Water Recreation Project and Campgrounds Project).

A BMP effectiveness water quality monitoring design will be used for the Slide Rock Parking Lot Project. Sampling will take place at the inflow and outflow of the detention basin. Variables include total suspended solids, BOD, total phosphorous, soluble phosphorous, total Kjeldahl nitrogen, nitrite, NO3, lead, copper, and zinc. Explanatory variables to be monitored are precipitation, runoff velocity, and pH. An event-based scheme will be used to monitor parking lot runoff. Automatic samplers placed at the inflow and outflow points of the detention basin will be triggered by rainfall and runoff events. A sample of the "first flush" will be deposited in the first bottle. Thereafter, a sample will be taken every 20 minutes and composited in the second bottle, "post flush."

Water Quality Data Management and Analysis

Raw data will be entered in STORET and project results will be reported using USEPA's Nonpoint Source Management System (NPSMS) software. Data will also be entered in a Geographical Information System.

Information, Education, and Publicity

The Oak Creek Advisory Committee, formed in 1992, involves federal, state, and local government agencies and private organizations such as Keep Sedona Beautiful and the Arizona River Coalition. The committee meets monthly to: keep participants informed of current project activities and results; gain insights into areas of concern; and learn about BMPs to be implemented as part of the 319 NMP project.

For Further Information Contact

Administration: Daniel Salzler, Arizona Department of Environmental Quality, Nonpoint Source Unit, 3033 N. Central, 3rd Floor, Phoenix, Arizona 85012-0600, Tel: (602) 207-4507; Fax: (602) 207-4467

Land Treatment: Tom Harrison, Director, Grants and Contracts, Northern Arizona University, Flagstaff, Arizona 86011, Tel: (602) 523-6727; Fax: (602) 523-1075

Water Quality Monitoring: Dr. Richard D. Foust, Department of Chemistry and Environmental Science, Northern Arizona University, Flagstaff, Arizona 86011, Tel: (602) 523- 7077; Fax: (602) 523-2626

Information and Education: Wilbert Odem, Department of Civil and Environmental, Engineering, Northern Arizona University, Flagstaff, Arizona 86011, Tel: (602) 523-4449; Fax: (602) 523-2600

Reference

Northern Arizona University Oak Creek Watershed Team. 1994. The Oak Creek 319(h) Demonstration Project National Monitoring Program Work Plan.

The following article is based on a fact sheet prepared as one of a series of 10 technical fact sheets designed to share the lessons learned from the Rural Clean Water Program (RCWP) (Gale et al., 1993; Spooner and Line, 1993) about nonpoint source pollution control projects with water quality and other natural resource professionals. Each fact sheet includes examples from several RCWP projects to illustrate the principles outlined below. The fact sheet series is now available (see enclosed publications list: WQ-89).

Land use and management affect the type and amount of nonpoint source (NPS) pollution entering water bodies. Improvements in land management (also called land treatment) are necessary to reduce the generation and delivery of pollutants to impaired or threatened water resources. Documentation of the magnitude of water quality improvements from changes in land management, for at least a few projects in each part of the country, is essential to provide feedback to project coordinators and state, regional, and national policy makers. Such feedback enhances the development and implementation of land treatment programs that effectively reduce pollutants causing water quality impairment. Also, demonstration that land treatment is effective in reducing NPS pollution and improving water quality tends to increase political and economic support for pollution control measures.

Historically, it has been difficult to demonstrate the relationship between land treatment and water quality changes, at least in part because of a lack of well-designed water quality and land treatment monitoring efforts. Two goals must guide the design of monitoring networks and data analysis in programs and projects designed to link water quality changes with best management practice (BMP) implementation: 1) detection of significant (or real) trends in both water quality and land treatment and 2) linking or associating water quality trends with land treatment trends.

This article outlines the principles for developing effective monitoring designs, and describes the monitoring elements necessary for linking land treatment or land use modifications with water quality changes.

Documenting a Cause-and-Effect Relationship

Documenting that water quality changes at a watershed scale were caused by the implementation of land treatment measures is difficult. Not only must a strong correlation be established, but the observed changes must be repeatable over time and space in an experimental manner. The only major changes made in the watershed during the evaluation period should be changes in land treatment. The observed changes in water quality should match the predicted pollutant reductions based on the estimated land treatment effectiveness. Some projects have been able to document a strong relationship, increasing our confidence that appropriate land treatment can result in improved water quality. The stronger the relationship, the more confident we can be that a cause-and-effect relationship exists and that water quality changes are caused by changes in land treatment rather than by other factors.

An association (statistically significant correlation or relationship) between land treatment and water quality changes is required to demonstrate a cause-and-effect relationship. As the implementation of land treatment (BMPs) occurs, improvements in water quality are observed. However, an association by itself is not sufficient to infer a cause-and-effect relationship. Other factors, such as changes in land use or rainfall, may be causing the changes in water quality. If, however, the association is consistent and responsive and has a mechanistic basis, causality may be supported (Mosteller and Tukey, 1977).

Consistency means that the relationship between the measured variables (such as total phosphorus and acres treated with the nutrient management BMP) holds in each data set in terms of direction and degree. A consistent, multi-year, improving trend in water quality after implementation of BMPs provides evidence needed to attribute water quality changes to land treatment. Similarly, improvements in multiple watersheds treated with BMP systems provide strong evidence that water quality improvements resulted from land treatment.

Responsiveness signifies that as one variable changes in a known, experimental manner, the other variable changes similarly. For example, as the amount of land treatment increases, further reduction of pollutant delivery to the water resource is documented.

Mechanistic means that the observed water quality change is that which is expected based on the physical processes involved in the installed NPS pollution reduction controls. For example, based on knowledge of the absorption and solubility of nutrients, greater reduction of nutrient delivery to the water resource might be predicted as the result of implementation of the manure management BMP than a soil erosion control practice alone.

Elements of Monitoring Needed to Link Land Management Modifications with Water Quality Changes

The paired watershed design is the best method for documenting BMP effectiveness in a limited number of years (3 - 5) (Clausen and Spooner, 1993). Two similar subwatersheds (drainage areas) are monitored before and after implementation of BMPs in one subwatershed (treatment area). Paired drainage areas should have similar precipitation and runoff patterns and should exhibit a consistent relationship in the magnitude of pollutant losses with hydrologic and climatic changes. Analysis of paired pollutant data from treatment vs. control areas should show a statistically significant correlation. Ideally, such a monitoring program is characterized by:

• Simultaneous monitoring at each drainage area outlet;

• Monitoring prior to land treatment to record the relative hydrologic response of each drainage area (calibration period);

• Calibration period of 1-3 years, depending on the consistency of data relationships between drainage areas;

• Subsequent monitoring where at least one drainage area continues to serve as a control (receives significantly less land treatment than the other drainage area); and

• Similar land management in both drainage areas both before and after BMP implementation, except for BMPs implemented in the treatment drainage area.

Sampling frequency and collection must be consistent across seasons and years. Year-to-year variability is often so large that at least two to three years each of pre- and post-implementation monitoring is required to indicate a consistent water quality change following implementation and maintenance of BMPs. Documentation of changes over multiple years increases confidence that observed water quality improvements are due to land treatment.

Short-term monitoring is seldom effective because climatic and hydrologic variability can mask water quality changes. In small watersheds affected by relatively few large pollutant sources, monitoring may be shorter. Longer duration monitoring is necessary where water quality changes are likely to occur gradually, such as in large watersheds with lakes in which lag times may occur due to buffering effects of long hydraulic residence times and pollutant recycling. Quantitative Monitoring of Land Management

The importance of recording the amount and type of land treatment cannot be overlooked when trying to document water quality improvements. Best management practices must be targeted to treat specific sources of pollutants causing the water quality impairment; these pollutants, in turn, must be monitored in the water resource. A high level of appropriate NPS pollution control implementation in critical areas is usually required to substantially improve water quality.

Monitoring of land treatment and land use is needed to quantify the pollutant reduction impacts of BMPs. Consistent quantitative monitoring of BMP implementation facilitates documentation of land treatment trends and is a necessary step in linking water quality to land treatment.

Careful planning is required to determine variables to be monitored. Land treatment data must be reported in quantitative units that reflect BMP effectiveness and changes from previous years. Examples of such units include application method, tons of manure spread, pounds of fertilizer applied per acre, and acres served by each BMP or BMP system. The acres served unit includes all treated acres plus all acres whose pollutant delivery is being reduced by the BMP. Assumptions used in calculating acres served should be documented so that these units can be calculated consistently from year to year. Care should be taken when reporting acres served to avoid double counting acres when multiple BMPs are applied on the same acres. Correction should also be given for differences in the effectiveness of the BMPs in controlling pollutant delivery. Operation, management, and maintenance of BMPs should be tracked because these factors affect BMP effectiveness and, thus, the water quality impacts of the land treatment.

Changes in land use should also be recorded in order to help isolate the water quality changes associated with the NPS controls from water quality changes due to other land use factors. Land use modifications that affect water quality include row crop acres converted to pasture(either permanently or based on rotation), set-aside acres, changes in animal density, closure of animal operations, changes in impervious land area, implementation of soil and water conservation practices not being recorded as part of the project, and changes in non-agricultural land uses.

Linkage of land treatment and water quality impacts can be made at different spatial scales (farm field, subwatershed, watershed). In general, the larger the drainage area, the harder it is to identify and quantify a water quality - land treatment linkage. Water quality changes are more likely to be observed at the subwatershed than watershed level. Confounding effects of external factors, other pollutant sources, and scattered BMP implementation are minimized at the subwatershed level. If the goal is to document watershed-level changes, a monitoring station must be located at the watershed outlet.

Water quality samples are usually collected weekly or biweekly. These data do not have to be summarized on the same time scale as the land treatment data. Land treatment data can be added to the trend analysis as repeating explanatory variables. Alternatively, water quality data can be aggregated to the same time scale as land treatment data, a useful procedure for plotting and explanatory data analysis.

Summary

A good experimental design for water quality and land treatment monitoring is essential to provide clear documentation of the relationship between land treatment and water quality changes. The paired watershed monitoring design can best demonstrate this relationship in the shortest time period. To determine if the trends in water quality match the mechanistic prediction of trends, pre- and post-BMP monitoring and data analysis must combine water quality, land treatment, and land use data on suitable spatial and temporal scales. Incorporation of explanatory variables facilitates isolation of water quality changes that result from land treatment.

References

Clausen, J.C. and J. Spooner. 1993. Paired Watershed Study Design. Office of Water, U. S. Environmental Protection Agency, Washington, DC. EPA 841-F-93-009. 8p.

Gale, J.A., D.E. Line, D.L. Osmond, S.W. Coffey, J. Spooner, J.A. Arnold, T.J. Hoban, and R.C. Wimberley. 1993. Evaluation of the Experimental Rural Clean Water Program. NCSU Water Quality Group, Bio. & Agric. Eng. Dept., NC State Univ., Raleigh, NC, EPA-841-R-93-005, 559p.

Mosteller, F. and J.W. Tukey. 1977. Data Analysis and Regression: Second Course in Statistics. Addison-Wesley Pub. Co., Reading, MA. 588 p.

Spooner, J. and D.E. Line. 1993. Effective Monitoring Strategies for Demonstrating Water Quality Changes from Nonpoint Source Controls on a Watershed Scale, Water Science Technology 28(3-5):143-148.

The Section 319 National Monitoring Program is mandated by Section 319 of the Clean Water Act as amended in 1987. Program goals are to: 1) document the water quality benefits of nonpoint source (NPS) pollution control programs; 2) improve understanding of the effectiveness of NPS efforts; and 3) develop better NPS projects. Funding for the program comes from a 5% setaside of annual Section 319 funds allocated to USEPA Regions.

This annual report on the Section 319 National Monitoring Program projects provides profiles of the 12 projects approved for USEPA funding as of September, 1994. The projects are Oak Creek Canyon (Arizona), Morro Bay Watershed (California), Eastern Snake River Plain (Idaho), Lake Pittsfield (Illinois), Sny Magill Watershed (Iowa), Warner Creek Watershed (Maryland), Sycamore Creek Watershed (Michigan), Elm Creek Watershed (Nebraska), Long Creek Watershed (North Carolina), Pequea and Mill Creek Watershed (Pennsylvania), Lake Champlain Basin Watersheds (Vermont), and Otter Creek (Wisconsin). A chapter on project selection, planning, and implementation is also included.

The report may be ordered (free) from NCEPI, P.O. Box 42419, Cincinnati, OH 45242, Tel: 513-489-8190, Fax: 513-489-8695. Limited copies are available (free) from NCSU Water Quality Group, 615 Oberlin Road, Suite 100, Raleigh, NC 27605-1126 (see enclosed publications list: WQ-88).

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 also available with each (hard copy) 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
Internet: notes_editor@ncsu.edu