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National Water-Quality Assessment (NAWQA) Program

#### U.S. Geological SurveyOpen-File Report 94-70

# Overview of the National Water-Quality Assessment Program

### *By* P.P. Leahy and T.H.Thompson

**INTRODUCTION**
**PROGRAM DESIGN**
**PROGRAM IMPLEMENTATION**
**EARLY FINDINGS**
**COMMUNICATION AND COORDINATION**

## INTRODUCTION

        The Nation's water resources are the basis for life and oureconomic vitality.  These resources support a complex web of humanactivities and fishery and wildlife needs that depend upon clean water. Demands for good-quality water for drinking, recreation, farming, andindustry are rising, and as a result, the American public is concernedabout the condition and sustainability of our water resources.  TheAmerican public is asking:  Is it safe to swim in and drink water from ourrivers or lakes?  Can we eat the fish that come from them?  Is our groundwater polluted?  Is water quality degrading with time, and if so, why? Has all the money we've spent to clean up our waters, done any good?  TheU.S. Geological Survey's **National Water-Quality Assessment (NAWQA)Program** was designed to provide information that will help answer thesequestions.

 NAWQA is designed to assess historical, current, and futurewater-quality conditions in representative river basins and aquifersnationwide.  One of the primary objectives of the program is to describerelations between natural factors, human activities, and water-qualityconditions and to define those factors that most affect water quality indifferent parts of the Nation.  The linkage of water quality toenvironmental processes is of fundamental importance to water-resourcemanagers, planners, and policy makers.  It provides a strong and unbiasedbasis for better decisionmaking by those responsible for making decisionsthat affect our water resources, including the United States Congress,Federal, State, and local agencies, environmental groups, and industry. Information from the NAWQA Program also will be useful for guidingresearch, monitoring, and regulatory activities in cost effective ways.

## PROGRAM DESIGN

        The NAWQA Program's unique design provides consistent andcomparable information on water resources in 60 important river basins andaquifers across the Nation.  Together, these areas account for 60 to 70percent of the Nation's water use and population served by public watersupplies and cover about one-half of the land area of the Nation. Investigations of these 60 areas, referred to as "study units," are theprincipal building blocks of the NAWQA Program.

 The similar design of each investigation and use of standardmethods make comparisons among the study unit's results possible.Regional and national assessments can be made.  These regional andnational assessments, referred to as "National Synthesis," focus on prioritynational issues, including non-point source pollution, sedimentation,and acidification.  Each issue is unique and manifests itselfdifferently among the Nation's diverse geographic, geologic,hydrologic, and climatic settings.  The challenge and goal for NAWQAis, therefore to identify the common environmental characteristicsassociated with the occurrence of key water-quality constituents andto explain their differences throughout the Nation.

## PROGRAM IMPLEMENTATION

        In 1991, NAWQA began the transition from a pilot program to afull-scale program with the start of 20 study-unit investigations, alongwith synthesis activities on a national scale.  In October, 1993 anadditional 20 study-unit investigations started.  When fully implementedin 1997, the program will include hydrologic investigations of 60 studyareas that are distributed throughout the Nation.To make the program cost effective and manageable, intensiveassessment activities in each of the study units are being conducted on arotational rather than a continuous basis, with one-third of the studyunits being studied intensively at any given time For each study unit, 3- to 5-year periods of intensive data collection andanalysis will be alternated with 5- to 6-year periods of less intensive studyand monitoring.  

Locations of the 60 NAWQA study units and their proposedimplementation dates (25K GIF)

Coinciding with the study-unit investigations are thenational synthesis assessments.  The large geographic extent and large variability in environmentalfactors throughout the Nation, and limited resources make it necessaryto focus on a limited set of high priority water-quality issues.Generally, two to four national synthesis topics will be studied at agiven time.  Two issues of national priority--the occurrence of nutrients and  pesticides in rivers andground water--were selected as the first issues investigated bynational synthesis.  These topics were ranked among the highest inimportance because of widespread environmental and public healthconcerns and because information necessary for a national assessmentof these contaminants was incomplete.

The next topic for national synthesis is the occurrence anddistribution of volatile organiccompounds (VOCs). Many VOCs are toxic and are a major focus of anumber of Federal regulations related to water quality.  Major workelements planned for the study of VOCs in 1994 and 1995 are to (1)identify regulated and non-regulated VOCs; (2) determine the amountsof VOCs released to water, land, and air, and (3) evaluate strategiesto characterize the use and releases of VOCs to the environment,including ground water.

The first two years of both study-unit investigations and nationalsynthesis studies involve compilation and analysis of existinginformation.  In addition to USGS data, information and methods developedby other Federal agencies, as well as by State and local agencies,universities, and volunteer organizations are reviewed and integrated asappropriate.  This preliminary information on water-quality conditions,trends, and functions forms the basis of a three-year period of intensivedata collection and analysis to fill identified gaps in subsequentyears.

Perennial data collection and sequential assessments in the studyunits and regional and national synthesis are key attributes of theprogram, not only to define changes and trends, but also to build anevolving understanding of water quality in each of the study units andacross the Nation.  This understanding will be achieved throughcareful analysis and interpretation of long-term data sets on thephysical, chemical, and biological characteristics of the waterresource.  The data sets will be related to carefully compiledinformation on hydrology and geology and changes in land-useactivities and management practices.  The long-term commitment of theNAWQA Program to water-quality monitoring at local, regional, andnational scales is designed to answer critical questions about thestatus and trends in the quality of our Nation's water.

## EARLY FINDINGS

The NAWQA Program is producingmany useful findings about our local, regional, and national waterresources.

### Highlights of NAWQA Study Unit Findings

- Hudson River Basin NAWQA team works with education groups to extend earth-sciencecurriculum (Map Area 4) -- The Hudson River NAWQA Team is working with the RiverWatch Network, the Adirondack Park Interpretive Centers, and theAdirondack Teacher's Center to help local high-school teachers expandtheir earth-science curriculum.  The program gives the schools the opportunity to measure chemical, physical, and biological characteristicsof streams in their area and to interact with other schools andwater-resource professionals in evaluating that data.
- Delmarva PeninsulaAgricultural chemicals inshallow ground-water on the Delmarva Peninsula (Map Area 8) --Water-qualitystudies in the Delmarva Peninsula indicated that concentrations ofnitrates are elevated in shallow ground water beneath agricultural areasand may pose a risk to those residents who drink shallow ground water fromthese areas.  The study also indicated that ground water with elevatedconcentrations of nitrate discharge to Chesapeake Bay and its tributaries,and is probably a significant source of nitrates to the ecosystem of theBay.  Pesticides, which are used primarily on corn and soybeans, weredetected at very low levels.  The concentrations are generally at levelsthat do not violate Federal drinking water standards.
- Western Lake Michigan DrainageLand use and soils affectnutrient and sediment levels in Western Lake Michigan Drainage (Map Area17) -- Land use was the primary factor influencing the distribution of nutrientand sediment concentrations in streams.  Concentrations were directlyrelated to the input from atmospheric deposition and fertilizer and manureuse.  Concentrations in stream runoff were highest from agricultural areas and urban areas and were lowest instreams draining forested areas.  The amount of clay in soils affects theoccurrence of some constituents, particularly in agricultural areas and inground water.  Significantly hig her concentrations of nitrates were foundin water draining agricultural areas with sandy soils than from those withclayey soils.  Trends in water-quality and sediment discharge from 1971 to1990 were also identified.
- Red River of the NorthGround watercontributes high levels of dissolved solids to Red River during periods oflow flow (Map Area 19) --Analyses of samples of ground water and samples fromtributaries and along the main stem of the Red River of the North showedthat during low stage and low flow conditions in March and December,ground water contributes a large percentage of the flow.  The groundwater contains significantly higher levels of dissolved solids thansnowmelt and surface runoff.  Flow from most tributaries contain higherlevels of dissolved solids than the main stem.  Reconnaissance sampling offish tissue and stream sediment showed only trace levels of heavy metals and organic carbons.
- Apalachicola-Chattahoochee-Flint River BasinPoultry and livestock contribute more than half the nutrient loads inthe Apalachicola-Chattahoochee-Flint River Basin (Map Area 23) --Nutrient loads to rivers were estimated using water-quality data from1990. Load sources included poultry and livestock, fertilizers,atmospheric deposition, and municipal wastewater treatment plants. In1990, more than half of the total nutrient loads, 120,000 tons oftotal nitrogen and 28,000 tons of phosphorus, came from poultry andmanure.
- Trinity River BasinNutrient levels remain unchanged in Trinity River Basin streams and ground water(Map Area 34)--Water-quality trends were evaluated for about 4,800 samples fromstreams and 1,500 samples from wells.  Concentrations of total nitrogenand phosphorous have not changed significantly from 1974 to 1991 at mostsites, although there was a decrease in phosphorous concentrations nearDallas.  Spatial variations in chemical concentrations in streams arerelated primarily to point sources and reservoirs.  The largest nutrientconcentrations occur downstream from Dallas, where streamflow is dominatedby treated wastewater.  The smallest concentrations occur just downstream fromreservoirs, which act as sinks for nutrients.  The largest concentrationsof nitrate in ground water have been detected in samples from the QueenCity and Nacatoch aquifers.  Concentrations tend to decrease withdepth.
- Lower Kansas River BasinPesticide management in theLower Kansas River Basin (Map Area 37) -- In the Lower Kansas River Basin, NAWQAfindings on the occurrence and temporal distribution of atrazine (aherbicide widely used in the production of corn and soybean) inwater-supply reservoirs were used by the Kansas State Board of Agricultureas the basis for establishing a pesticide management area in northernKansas.  The management area is the first in the Nation that focuses onreducing the amount of atrazine in runoff to streams and reservoirs.
- Rio Grande ValleyFew pesticides found in ground water in the upper Rio Grande Valley(Map Area 46) --In an area of intense agriculture in the San Louis Valley,Colorado, the northern part of the Rio Grande Valley Study Unit,pesticides were detected in only 5 of the 35 wells installed in theshallow aquifer .  The monitor wells are dispersed among 2000 center-pivot irrigation systems covering about 270,000 acres.  Major cropsinclude alfalfa, potatoes, small grains, and vegetables.  Samples from thewells were analyzed for 90 pesticides and their degradation products.  Atotal of four pesticides (metolachlor, p,p'DDE, metribuzin, and prometon)were detected in the upper 10 feet of the saturated zone, with a maximumconcentration of .07 micrograms per liter.
- Upper Snake River BasinNitrate concentrations do not meet state and federal drinkingwater standards in three areas of Upper Snake River Basin (Map Area 49) --Water-quality data from the files of the USGS and the EnvironmentalProtection Agency collected from 1980 to 1991 showed nitrateconcentrations in samples of ground water at three locations failed tomeet Federal and State drinking water standards and were greater than 10milligrams per liter.  These samples were from wells at the Idaho NationalEngineering Laboratory, the Fort Hall area north of Pocatello, Idaho, andthe area surrounding Burley, Idaho.  Nitrate concentrations are increasingthrough time in eight wells near Burley and northwest of Pocatello. Organic compounds were detected in 17 of the 211 wells sampled.
- Yakima River BasinDDT in the Yakima River Basin (Map Area 52) --In the Yakima River Basin, the insecticide DDT, bannedmore than 20 years ago, was detected at elevated concentrations in water,stream sediment, and fish tissue.  These findings suggest a potentialhealth concern, especially to the local population of Native Americanswho rely on fish as a major source of food, and pose a continued threat tofish-eating birds.  The DDT contamination is related to the erosion ofcontaminated soils in irrigated areas.
- Nevada Basin and RangeRadon found in ground water in Nevada Basin andRange (Map Area 56) --Radon, a gas resulting from the natural decay of uranium,has been found in water from a number of wells used for domestic supply inthe Carson and Truckee River Basin.  Radon concentrations greater than2000 picocuries per liter (pCi/L) are common in sam ples from wells in thewestern portions of the basins near Lake Tahoe.  The Nevada Division ofHealth recommends that water be treated when radon levels indrinking-water supplies exceed 300 pCi/L.

### Selected early results from the National Synthesis on Pesticides andNitrates include the following:

- A review of existing information on pesticides in the atmosphereshowed that pesticides have been detected in most samples analyzedthroughout the Nation.  Pesticides were ubiquitous and were generallydetected wherever they were sought.  The degree of use and environmentalpersistence explain the dominant patterns in frequency of detection.  Thereview revealed that no consistent, long-term studies at a national scalehave been done.
- A statistical analysis of the occurrence of nitrate in streams atabout 150 sites in 10 states in the Midwest, showed there was arelation between the concentration of nitrate and each of thefollowing: the amount of precipitation, rate of streamflow, theacreage of the basin planted in corn, the acreage planted in soybeans,cattle density, and population density.  These findings help State andlocal managers to focus scarce monitoring resources to the mostcritical areas.
- Estimates of point- and nonpoint-source nitrogen loadings were madefor about 90 watersheds throughout the United States.  The relativeproportions of input to streams vary as a function of climate, hydrology,land use, population, and physiography.  A large percentage ofpoint-source loads occur near cities.  Nonpoint loading varies widely, andis strongly influenced by precipitation and runoff.  However, no singlenonpoint-nitrogen source is dominant everywhere.  Information derived fromNAWQA study units will aid in the development of methods to reduce point- and nonpoint-source nitrogen loading.
- Effects of agricultural activities on ground-water quality was studiedin five regions from New York to Nebraska.  The quality of water insurficial, unconsolidated aquifers was affected by the geology and soils,land-management practices, fertilizer use, and the amount of irrigation. Concentrations of nitrate were greatest in areas that are heavilyirrigated or areas that have well-drained soils or sediments.  

Results from the NAWQA Program are being released to the public through avariety of publications as elements of the studies are completed.

## COMMUNICATION AND COORDINATION

        Communication and coordination between U.S. Geological Surveypersonnel and other interested scientists and water-managementorganizations are critical components of the NAWQA program.  Early in theprogram, the National Academy of Sciences reviewed the proposedactivities and issued a report supporting the program.  Since 1991, theNAWQA Advisory Council, a panel of Federal scientists, has met to ensureuse of the best and most current scientific methods and to ensure nationalrelevance of the program's findings.  In 1993, representatives fromNational, State, and regional organizations; Native American groups;professional and technical societies; public interest groups; privateindustry; and the academic community were invited to join the Council. At the study-unit level, each investigation now underway has a localliaison committee consisting of representatives with water-resourcesresponsibilities or interests from Federal, State, and local agencies,universities, and the private sector.  Specific activities of eachliaison committee include (1) the exchange of information aboutwater-quality issues of regional and local interest, (2) theidentification of sources of data and information, (3) assistance in thedesign and scope of project products, and (4) the review of projectplanning documents and reports.

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For further information about this report, contact the NationalWater-Quality Assessment Program office.

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