Water-quality Assessment Of The Hudson 

River Basin In New York And Adjacent States -

Analysis of available nutrient, pesticide, volatile organic 

compound, and suspended-sediment data, 1970-90

By Patrick J. Phillips and Dorothea W. Hanchar

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 96-4065

Troy, New York 

1996
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

Gordon Eaton, Director

For additional information 

write to:

District Chief

U.S. Geological Survey, WRD

425 Jordan Road

Troy, N.Y. 12180

Copies of this report can be 

purchased from:

U.S. Geological Survey

Branch of Information Services

Federal Center

Box 25286

Denver, CO 80225-8286
FOREWORD

The mission of the U.S. Geological Survey (USGS) is to assess the quantity and quality of the earth 

resources of the Nation and to provide information that will assist resource managers and policymakers at 

Federal, State, and local levels in making sound decisions. Assessment of water-quality conditions and trends 

is an important part of this overall mission.

One of the greatest challenges faced by water-resources scientists is acquiring reliable information that 

will guide the use and protection of the Nation's water resources. That challenge is being addressed by Federal, 

State, interstate, and local water-resource agencies and by many academic institutions. These organizations are 

collecting water-quality data for a host of purposes that include: compliance with permits and water-supply 

standards; development of remediation plans for a specific contamination problem; operational decisions on 

industrial, wastewater, or water-supply facilities; and research on factors that affect water quality. An additional 

need for water-quality information is to provide a basis on which regional and national-level policy decisions 

can be based. Wise decisions must be based on sound information. As a society we need to know whether certain 

types of water-quality problems are isolated or ubiquitous, whether there are significant differences in 

conditions among regions, whether the conditions are changing over time, and why these conditions change 

from place to place and over time. The information can be used to help determine the efficacy of existing waterquality policies and to help analysts determine the need for and likely consequences of new policies.

To address these needs, the Congress appropriated funds in 1986 for the USGS to begin a pilot program 

in seven project areas to develop and refine the National Water-Quality Assessment (NAWQA) Program. In 

1991, the USGS began full implementation of the program. The NAWQA Program builds upon an existing base 

of water-quality studies of the USGS, as well as those of other Federal, State, and local agencies. The objectives 

of the NAWQA Program are to:

 Describe current water-quality conditions for a large part of the Nation's freshwater streams, rivers, and 

aquifers.

 Describe how water quality is changing over time.

 Improve understanding of the primary natural and human factors that affect water-quality conditions.

This information will help support the development and evaluation of management, regulatory, and monitoring decisions by other Federal, State, and local agencies to protect, use, and enhance water resources.

The goals of the NAWQA Program are being achieved through ongoing and proposed investigations of 60 

of the Nation's most important river basins and aquifer systems, which are referred to as study units. These study 

units are distributed throughout the Nation and cover a diversity of hydrogeologic settings. More than two-thirds 

of the Nation's freshwater use occurs within the 60 study units and more than two-thirds of the people served 

by public water-supply systems live within their boundaries.

National synthesis of data analysis, based on aggregation of comparable information obtained from the 

study units, is a major component of the program. This effort focuses on selected water-quality topics using 

nationally consistent information. Comparative studies will explain differences and similarities in observed 

water-quality conditions among study areas and will identify changes and trends and their causes. The first 

topics addressed by the national synthesis are pesticides, nutrients, volatile organic compounds, and aquatic 

biology. Discussions on these and other water-quality topics will be published in periodic summaries of the 

quality of the Nation's ground and surface water as the information becomes available.

This report is an element of the comprehensive body of information developed as part of the NAWQA 

Program. The program depends heavily on the advice, cooperation, and information from many Federal, State, 

interstate, Tribal, and local agencies and the public. The assistance and suggestions of all are greatly appreciated.

Robert M. Hirsch, 

Chief Hydrologist

Foreward iii
CONTENTS

Foreword ........................................................................... iii

Abstract............................................................................ 1

Introduction......................................................................... 2

Purpose and Scope .............................................................. 2

Acknowledgments............................................................... 2

Hudson River Basin................................................................... 3

Environmental Setting............................................................ 3

Precipitation and Runoff.......................................................... 9

Aquifers....................................................................... 12

Reservoirs ..................................................................... 14

Upper Hudson Subbasin...................................................... 14

Mohawk River Subbasin...................................................... 14

Lower Hudson Subbasin...................................................... 14

Water Use ..................................................................... 16

Pesticide Use................................................................... 16

Water-Quality Assessment.............................................................. 20

Approach ..................................................................... 20

Ground-Water Data.......................................................... 20

Surface-Water Data.......................................................... 20

Site Selection......................................................... 20

Data Sources......................................................... 21

Methods of Analysis ................................................... 21

Ancillary data. ........................................................ 22

Land Use......................................................... 22

Nutrient-Input Rates ................................................ 22

Land-Use Categories ........................................................ 23

Availability of Data, 1970-90 ...................................................... 24

Ground water .............................................................. 24

Nutrients............................................................. 24

Pesticides and Volatile Organic Compounds ................................. 24

Surface Water.............................................................. 24

Nutrients ............................................................ 29

Suspended Sediment ................................................... 33

Pesticides............................................................ 36

Analysis of Nutrient, Pesticide, Volatile Organic Compound, and Suspended-Sediment Data ......... 39

Ground Water .................................................................. 39

Nitrate.................................................................... 39

Pesticides and Volatile Organic Compounds ...................................... 42

Surface Water ............................ ....................................... 42

Nutrients.................................................................. 43

Concentration in relation to Discharge .................................... 43

Small Agricultural Watershed ......................................... 44

Large Agricultural Watershed ......................................... 45

Urban Watershed................................................... 46

Forested Watersheds ............................................... 47

iv Contents
Concentration in relation to Time.......................................... 47

Concentration in relation to Land Use and Population Density ................... 50

Yields ............................................................... 55

Nutrient Inputs.................................................... 60

Mass Balance .................................................... 64

Suspended Sediment ............................................................ 66

Concentration.............................................................. 66

Yields. .................................................................... 66

Pesticides ..................................................................... 69

Summary and Conclusions............................................................. 72

Ground Water.................................................................. 72

Surface Water.................................................................. 72

References Cited..................................................................... 75

FIGURES

1 -2. Maps of Hudson River basin in eastern New York and adjacent States showing:

1. Physical features:

A. Boundaries of three subbasins and major tributaries to the Hudson River. ............... 4

B. Counties .................................................................. 5

C. Ecozones. ................................................................. 6

D. Generalized bedrock geology. ................................................. 7

E. Generalized boundaries of the physiographic provinces.............................. 8

2. Precipitation and runoff

A. Mean annual precipitation .................................................... 10

B. Mean annual runoff ......................................................... 11

3. Boxplots showing:

A. Mean daily discharge, by month, for Mohawk River at Cohoes, N.Y., 1929-91 and

Wappinger Creek near Wappingers Falls, N.Y., 1929-91................................. 12

B. Mean annual discharge for Mohawk River at Cohoes, N.Y, 1970-90, and

Wappinger Creek near Wappingers Falls, N.Y, 1970-90. ............................... 12

4-5. Maps of Hudson River basin showing:

4. Locations of unconsolidated aquifers ............................................... 13

5. Location of major reservoirs ...................................................... 15

6. Graphs showing estimated application of pesticides in the Hudson and Raritan River basins, 

1940-80:

A. DDT by year, B. DDT by land use, C. Chlordane by year. ............................... 17

7-8. Maps of the Hudson River basin showing:

7. Estimated 1986 rates of pesticide application by county:

A. Alachlor. B. Atrazine......................................................... 18

C. Carbaryl. D Chlorothalonil .................................................... 19

8. Locations of wells for which 1970-90 analyses were available:

A. Dissolved nitrate............................................................ 26

B. Pesticides and volatile organic compounds ....................................... 27

Contents
FIGURES (CONTINUED)

9. Bargraphs showing depth and time distribution for dissolve nitrate analyses of water samples 

from unconsolidated and bedrock aquifers in the Hudson River basin, 1970-90: 

A. Sample distribution by well depth B. Sample distribution by year. ...................... 29

10. Map of the Hudson River basin showing locations of surface-water sites for which

1970-90 nutrient data were available ................................................ 30

11. Bargraph showing number of samples collected in Hudson River basin for dissolved nitrate 

analyses, 1970-90 at (A) Wappinger Creek near Wappingers Falls, and (B) Mohawk River 

at Crescent Dam, by month ....................................................... 33

12-13. Map of Hudson River basin showing locations of surface-water sites from which 1970-90 

data were available for:

12. Suspended sediment .......................................................... 34

13. Pesticides................................................................... 37

14. Bargraphs showing .number of Hudson River basin sites from which bed-sediment 

concentrations of total DOT, and 2,4-D are available, by land-use 

category, 1970-90............................................................... 38

15. Graph showing dissolved nitrate concentrations in water from wells representing bedrock 

and unconsolidated aquifers in the Hudson River basin as a function of normal distribution, 

1970-90. ...................................................................... 39

16. Boxplots showing range of dissolved nitrate concentrations in relation to aquifer type in 

Hudson River basin, 1970-90 for :

A. All aquifers in the Hudson River basin. B. Unconsolidated aquifers in Albany and 

Schenectady counties and bedrock aquifers in Westchester counties........................ 40

17. Graph and boxplot of dissolved nitrate concentrations in water samples from unconsolidated 

and bedrock aquifers in the Hudson River basin, 1970-90: 

A. Concentrations as a function of depth. B. Concentration range in shallow and deep wells..... 41

18. Boxplots showing range of dissolved nitrate concentrations in samples from (A) unconsolidated

aquifers, and (B) bedrock aquifers, in the Hudson River basin, 1970-90, by land use........... 42

19. Graphs showing concentration of dissolved nitrate, total nitrogen, dissolved ammonium, 

and total phosphorus in relation to discharge at two agricultural watersheds, 1970-90: 

A. Small watershed (Wappinger Creek near Wappingers Falls), ........................... 44

B. Large watershed, (Mohawk River at Crescent Dam). ................................. 45

20-22. Graphs showing concentration in relation to discharge, 1970-90:

20. Dissolved nitrate at a large watershed site (Mohawk River outlet), 1970-90: 

A. At Crescent Dam, based on season 

B. At Crescent Dam and Cohoes, based on all data................................... 46

21. In two urban watersheds: A. Dissolved nitrate and total phosphorus concentration at 

Hoosic River below Williamstown, Mass. B. Total nitrogen at Hoosic River near North 

Petersburg, N.Y................................................................ 47

22. Dissolved nitrate, total nitrogen, and total phosphorus at two forested watersheds, 

1970-90: 

A. Esopus Creek at Shandaken, B. Hudson River at Corinth ........................... 48

23. Graphs showing nitrate concentrations in two Catskill streams with long-term records

through 1990................................................................... 49

24. Boxplots showing distribution of median dissolved nitrate, total nitrogen, dissolved 

ammonium, and total phosphorus concentrations at five sites in the Hudson River 

basin, 1970-90 ................................................................. 51

vi Contents
FIGURES (CONTINUED)

25. Map of Hudson River basin showing locations of sites used in basinwide comparison

of nutrient concentrations ......................................................... 52

26. Boxplots showing distribution of median dissolved nitrate, total nitrogen, and total

phosphorus concentrations in agricultural, urban and mixed-use, and forested watersheds

used in basinwide comparison of nutrient concentrations................................. 54

27.Graphs showing median concentration of dissolved nitrate, total nitrogen, and total

phosphorus in relation to watershed population at surface-water sites in the Hudson River basin. . 55

28. Map of Hudson River basin showing locations of surface-water sites with computed nutrient

yields for 1970-80 and 1981-90. .................................................... 58

29. Graphs showing average annual 1970-80 nutrient yields as a function of percentage of basin

used for agriculture, and population density ........................................... 59

30. Bargraphs showing annual 1970-80 inputs and yields of nutrients at Hudson River at 

Corinth, Mohawk River at Fonda, Hudson River at Waterford, Hudson River at Green 

Island, and Hoosic River at North Petersburg, by sources: 

A. Nitrogen and B. Phosphorus ..................................................... 63

31. Graphs showing concentration of suspended-sediment as a function of discharge, 1970-90,

for Hudson River at Stillwater and Mohawk River at Cohoes. ............................. 66

32. Boxplots showing distribution of median suspended sediment concentration at sites for

which 1970-90 data are available ................................................... 67

33. Graph showing sediment yield as a function of percentage of watershed that is forested......... 68

34. Graphical summary of urban and nonurban streambed-sediment concentrations of DDT, 

chlordane, and 2,4-D for sites in Hudson River basin, 1970-90, by: 

A. Percent detection B. Median detection.. ........................................... 70

35-36. Graphs showing concentrations of pp'-DDD and chlordane with time in Hudson River 

sediments collected by Bopp and others (1982):

35.pp'-DDD ................................................................... 71

36. Chlordane in core E, collected at river mile 3 near Manhattan Island..................... 71

TABLES

1. Area and land-use characteristics of the Hudson River basin and its three subbasins. ............ 13

2. Estimated water use in the Hudson River basin ......................................... 16

3. Estimated agricultural use of selected pesticide compounds in the Hudson River basin, 1986 ..... 17

4. Characteristics of wells in the Hudson River basin for which water-quality data are available,

1970-90 ........................................................................ 25

5. Name, location and drainage area, and types of data available from surface-water sites in the 

U.S. Geological Survey National Water Inventory System database from which nutrient, 

suspended-sediment, or pesticide data are available. ..................................... 28

6. Land use and population density of watersheds represented by the 56 surface-water sites in

the Hudson River basin from which 1970-90 nutrient data were available..................... 31

7. Number of samples collected at selected sites in the Hudson River basin for nutrient

analysis, 1970-90. ................................................................ 32

8. Number of dissolved nitrate samples collected per year at selected sites with discharge data in

the Hudson River basin, 1970-90..................................................... 32

Contents vii
TABLES (CONTINUED)

9. Number of samples collected for dissolved nitrate at high and low flows for select sites in

the Hudson River basin, 1970-90. .................................................... 33

10. Data on numbers of samples collected at eight sites in the Hudson River basin, that have

discharge records and more than 40 suspended-sediment samples, 1970-90 ................... 35

11. Years of pesticide-data collection in the Hudson River basin, 1970-90, by site ................. 38

12. Detection limits of selected pesticides and volatile organic compounds for which ground-water

samples from the Hudson River basin were analyzed, 1970-90............................... 43

13. Sites used for basin wide comparison of median nutrient concentrations....................... 53

14. Spearman nonparametric correlation coefficients for correlation of basin wide median nutrient

concentrations with land use and population density. ..................................... 53

15. Number and flow characteristics of samples used to calculate average annual yields. ............ 56

16. Annual nutrient yields and standard errors of estimate at sites for which data are adequate for

analysis, 1970-80.................................................................. 60

17. Average annual nitrogen and phosphorus inputs, source of input, average annual yield and ratio of 

yield to total input for sites in the Hudson River basin for which sufficient data are available for 

analysis ........................................................................ 62

18. Average mass of nutrients transported at selected sites in the Upper Hudson and Mohawk River

subbasins for 1977-80. ............................................................ 65

19. Discharge characteristics represented by samples used to calculate suspended-sediment

yields in the Hudson River basin...................................................... 67

20. Suspended-sediment yields calculated for sites in the Hudson River basin. .................... 68

Contents
CONVERSION FACTORS AND VERTICAL DATUM

Multiply

inch (in)

feet (ft)

mile (mi)

square mile (mi2 ) 

square mile (mi2 )

gallon (gal)

million gallons per day (Mgal/d)

billion gallons per day (Bgal/d)

cubic foot per second (ft3/s)

degree Fahrenheit (°F)

by

Length

2.540

0.3048

1.609

Area

2.590

0.0259

Volume

3.785 

Flow

3.785

3.785

0.02832

Temperature 

0.5556(°F - 32 )

To Obtain

centimeter

meter

kilometer

square kilometer 

hectare

liter

million liters per day 

billion liters per day 

cubic meter per second

degree Celsius

Other Abbreviations

tons per year (ton/yr)

micrograms per kilogram (Hg/kg)

milligrams per liter (mg/L)

micrograms per liter (Hg/L)

tons per day per square mile ([ton/d]/mi2) 

inches per year (in/yr)

pounds per square mile (lb/mi2)

Water Year

The 365-day period from October 1 through September 30 of the following year. 

The water year is designated by the calendar year in which it ends.

Contents ix

Water-Quality Assessment of the Hudson River Basin 

in New York and adjacent States

Analysis of Available Nutrient, Pesticide, Volatile Organic Compound 

and Suspended-Sediment Data, 1970-90.

By Patrick J. Phillips and Dorothea W. Hanchar

ABSTRACT

The Hudson River basin encompasses about 

13,300 mi2 in parts of eastern New York, Vermont, 

New Jersey, Massachusetts, and Connecticut. More 

than 60 percent of the basin is forested, and about 25 

percent is agricultural; only 7.8 percent is urban. This 

report presents analysis of data from the U. S. 

Geological Survey NWIS (National Water Information System) collected during 1970-90 as part of 

several water-quality studies.

The ground-water data analysis given herein represents nutrient concentrations at 100 wells and pesticide and volatile organic compound concentrations at 

11 wells; well-depth and hydrogeologic information 

are available for all wells used in the analysis. The 

distribution of wells for which water-quality data are 

available is uneven throughout the study area. Nitrate 

concentrations in water from unconsolidated aquifers 

range from less than the analytical detection limit of 

0.1 mg/L (milligram per liter) to 16 mg/L, with a 

median concentration of 0.23 mg/L, and those from 

bedrock aquifers range from less than 0.1 to 11 mg/L, 

with a median concentration of 0.3 mg/L. Nitrate 

concentrations decrease with depth in unconsolidated 

aquifers, but not in bedrock. Concentrations of all 

pesticides and volatile organic compounds in samples 

from the 11 wells with data were at or below the 

analytical detection limits, except for diazinon, which 

was detected at concentrations below 0.04 jug/L 

(micrograms per liter) at one well (in Schenectady 

County, N. Y.). Data are insufficient for correlation of 

nutrient and pesticide concentrations in ground water 

with land use in the Hudson River basin.

Data on nutrient concentrations in surface water 

are sufficient for an assessment of water-quality 

conditions in large watersheds (greater than 200 mi2) 

dominated by agriculture and forest cover and in two 

watersheds dominated by urban, residential, or industrial land. Pesticide data are sufficient for analysis for 

DDT, chlordane, and aldrin in streambed sediments, 

and for 2,4-D in the water column. Most of the pesticide analyses were done during 1972-77.

In general, median nutrient concentrations in 

streams that drain urban watersheds (those that are 

more than 7.8 percent urban, residential, and industrial land and less than 20 percent agricultural land) 

and agricultural watersheds (those that are more than 

25 percent agricultural land and less than 11.5 percent 

urban land) exceed those in streams that drain 

forested watersheds (those that are more than 78 

percent forest). Nutrient yields (mass transported per 

year per unit area) during 1970-80 differ among 

streams depending on land use. The highest yields for 

dissolved nitrate, total nitrogen, and total phosphorus 

were in streams that drain agricultural and urban 

watersheds; these yields exceeded 3,200 lb/mi2 

(pounds per square mile) for dissolved nitrate, 4,200 

lb/mi2 for total nitrogen, and, 450 lb/mi2 for total 

phosphorus. The lowest nutrient yields were from 

streams that drain large forested watersheds (drainage 

areas greater than 2,000 mi2) and the two sites 

dominated by agricultural land on Schoharie Creek; 

dissolved nitrate yields at these two sites were less 

than 1,700 lb/mi2, and total nitrogen yields were 

generally less than 3,400 lb/mi 2 . Total phosphorous 

yields from the large forested watersheds were less 

than 150 lb/mi2 , but those from Schoharie Creek sites

Abstract 1
were somewhat higher (231 and 396 lb/mi 2, respectively). The low yields from the Schoharie Creek sites 

could be the result of water diversions from the upper 

reaches of the creek to reservoirs.

Estimated nutrient inputs from fertilizer, manure, 

sewage, and atmospheric deposition to each watershed indicate that (1) the major sources of nitrogen 

and phosphorus in Hudson River watersheds correspond to the predominant land use, and (2) the largest 

inputs result from agricultural activities. Most of the 

nitrogen and phosphorus inputs to agricultural watersheds were derived from manure and fertilizer, and 

most of the nitrogen input to forested watersheds was 

derived from atmospheric deposition; nitrogen inputs 

to urban watersheds could not be attributed to any 

predominant source. Phosphorus input was mostly 

from agricultural sources at all sites except those in 

urban-watersheds. These results indicate that nutrient 

inputs to the largest streams in the Hudson River 

basin were largely derived from nonpoint agricultural 

sources.

Sediment concentrations and transport rates reflect 

land use. The lowest median suspended-sediment 

concentrations and transport rates were in forested 

watersheds; in contrast, the highest median 

suspended-sediment concentration (26 mg/L) and 

transport rates (0.36 tons per day per square mile) 

were at the outlet of the Mohawk River basin, a watershed with little forest cover.

The available pesticide data indicate that pesticide 

concentrations can be related to spatial patterns of 

application. DDT was applied to agricultural, urban, 

and forested areas during 1940-72 and was detected at 

nearly all sites from which data were available, 

regardless of predominant land use. In contrast, chlordane has been applied primarily to urban lands since 

1945 and was detected primarily at sites in urban 

watersheds.

INTRODUCTION

In 1991, the U. S. Geological Survey (USGS) 

implemented the National Water Quality Assessment 

(NAWQA) Program to:

1. Provide a nationally consistent database on the 

present chemical quality of the Nations's major 

surface-water and ground-water resources,

2. Define long-term trends (or lack of trends) in water 

quality, and

3. Identify, describe, and explain, to the extent 

possible, the major factors that affect the observed 

water-quality conditions and trends.

The NAWQA Program is designed to integrate 

water-quality data collected from areas of many sizes. 

To this end, data are being collected in 60 "study 

units" across the nation that, together, represent 

between 60 and 70 percent of the nations's groundwater and surface-water resources. The study units 

include most major river basins and aquifer systems, 

or large parts of aquifers, and encompass 1,200 to 

more than 50,000 mi2 . The Hudson River basin was 

one of the first 20 study units selected for investigation when the NAWQA program began in 1991. 

Results from the study units are to be used as part of 

a national synthesis to describe the nation's waterquality conditions.

An initial effort of each study-unit project entailed 

compiling, screening, and analyzing (1) the available 

water-quality data for nutrients (nitrogen and 

phosphorus), suspended sediment, pesticides, and 

volatile organic compounds, and (2) pertinent hydrologic, land-use, and land-cover information to 

provide an initial description of surface-water and 

ground-water quality.

Purpose and Scope

This report presents results of analyses of data 

from NWIS (National Water Inventory System) of the 

USGS and selected data from other agencies in the 

Hudson River basin. It (1) describes the hydrologic 

environment of the basin, (2) summarizes the 

approach, the data bases, and site characteristics, and 

(3) presents analyses of nutrient, pesticide, and 

volatile organic compounds in ground water and of 

nutrients, pesticides, and sediment in surface water, in 

relation to land use. It also defines temporal trends.

Acknowledgments

Special thanks are given to members of the 

liaison committee of the Hudson River basin project 

for their continuous support during this effort. The 

authors also thank Douglas A. Freehafer and Gary R. 

Wall of the U.S. Geological Survey for their work on 

maps and graphs in the report. Technical reviews 

were provided by Douglas A. Burns and Mark Ayers 

of the U.S. Geological Survey.

2 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
HUDSON RIVER BASIN

The Hudson River basin encompasses about 

13,300 mi2 and lies in parts of eastern New York, 

Vermont, New Jersey, Massachusetts, and Connecticut (fig. 1 A). It contains a diversity of geologic, 

topographic, climatic, and hydrologic settings that are 

reflected in the patterns of land use. The basin 

consists of three major subbasins -the upper Hudson, 

the Mohawk, and the lower Hudson (fig. 1 A). The 

upper Hudson subbasin includes the Hudson River 

drainage above the confluence of the Hudson and 

Mohawk River and has an area of more than 4,600 

mi2 . The Mohawk subbasin consists of the drainage 

of the entire Mohawk River above its confluence with 

the Hudson River and has an area of about 3,500 mi2 . 

The lower Hudson subbasin, the largest of the three 

subbasins, consists of the Hudson River drainage 

below the confluence of the Hudson and Mohawk 

Rivers and has an area of about 5,200 mi 2. These three 

subbasins include parts of more than 35 counties (fig. 

IB).

Environmental Setting

The Hudson River basin contains a wide variety of 

land uses and environmental settings. The amount of 

urban, agricultural, and forested land in each of the 

three subbasins, and the predominant land uses in 

each, are summarized in table 1. The land-use classification used in this report is based on digitized landuse maps made from high-altitude photography and 

satellite imagery obtained in the mid 1970s (U.S. 

Geological Survey, 1979a, b c, d;1980a, b). Because 

many areas have probably undergone land-use 

changes since then, especially those near urban areas, 

the land-use classifications may be inaccurate in 

places. The environmental settings, termed ecozones, 

reflect landforms, topography, bedrock geology, soil 

productivity, climate, and forest type and are delineated in Figure 1C. The generalized bedrock is 

indicated in figure ID, and the physiographic 

provinces in figure IE.

The upper Hudson subbasin, which forms the 

northern part of the study area (fig. 1 A), covers about 

one-third of the Hudson River basin. Most of the 

subbasin is in the Adirondack Highlands-the 

Taconic Highland and Hudson Valley make up the 

rest (fig. 1C). Major rivers (those that drain more 

than 10 percent of the subbasin area) in the upper

Hudson subbasin include the Hudson, Sacandaga, 

Schroon, Battenkill, and Hoosic Rivers. About 76 

percent of the subbasin is forest, and 15 percent is 

farmed; only 3.4 percent is urban (table 1). Agricultural land is generally concentrated in the southeastern part of the subbasin, and most urban areas are 

along the Hudson River (Glens Falls and Troy) and 

along the upper reaches of the Hoosic River (North 

Adams, Mass., and Bennington, Vt). The 40-mi 

section of the Hudson River south of Fort Edward has 

been designated a "Superfund" site by the U.S. 

Environmental Protection Agency (USEPA) because 

its bed sedi-ments contain PCBs (polychlorinated 

biphenyls) (Limburg, 1985). This subbasin is underlain primarily by crystalline rocks, including 

anorthosite, gneiss, and granodiorite (fig. ID). Relief 

is greatest in the Adirondack Mountains, where 

altitudes exceed 3,000 ft. locally.

The Mohawk River subbasin, in the west-central 

part of the study unit, covers about a quarter of the 

study area (fig. 1A). It lies mostly in the Mohawk 

Valley but extends into the Appalachian Plateau, 

Adirondack Mountain, Tug Hill, and Great Lakes 

Plain (fig. 1C). Major rivers in the Mohawk River 

subbasin include the Mohawk River, Schoharie 

Creek, and West Canada Creek. About 55 percent of 

the subbasin is forested, nearly 40 percent is farmed, 

and 6.2 percent is urban. Agricultural land is generally concentrated within 20 mi of the Mohawk River 

and lower reaches of Schoharie Creek. Urban areas, 

including Utica, Amsterdam, and Schenectady, are 

along the Mohawk River. The subbasin is underlain 

predominantly by clastic rocks-mostly shale and 

sandstone (fig. ID). Relief is greatest in the Catskill 

Mountains (fig. IE), where altitudes exceed 3,000 ft 

locally.

Table 1. Area and land-use characteristics of the Hudson 

River basin and its three subbasins in New York and 

adjacent States.

[Locations are shown in fig. 1]

Subbasin

Upper Hudson

MohawkRiver

Lower Hudson

Entire Basin

Area 

(square 

miles)

4,620

3,450

5,230

13,300

Percentage of area

Urban

3.4

6.2

13

7.8

Agricultural

15

34

29

25

Forest

76

55

55

62

Hudson River basin 3
76' 75' 74 e 73°

44°

43'

42 e

41'

/)7./>..<2

Adirondack 

Mountains VERMONT

EXPLANATION

 .. .. Basin boundary

_.. .. Subbasin boundary 

Mohawk and name

Surface-water station

1 Mohawk River at Cohoes

2 Wappinger Creek at 

Wappingers Falls

0 10 20 30 40 50 MILES

I I I I I I

I TT I \ I

0 10 20 30 40 50 KILOMETERS

V^Mohawk \Schenetady

C a t s k i I I 

Mountains

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 1 A. Surface drainage and subbasin boundaries in the Hudson River basin in New York and adjacent States.

4 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
76 c 75' 74° 73°

VERMONT

Warren / " Rutland

Sehenedady 

Montgomery ./>^ ft :| &J "~i

;^x^

I Otsego } schoharte /: A, , J .- Albany (

p I

MASSACHUSETTS

EXPLANATION

County boundary

0 10 20 30 40 50 MILES

I I I I

0 10 20 30 40 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 1B. County boundaries in the Hudson River basin in New York and adjacent States.

Hudson River basin 5
76' 75' 74° 73°

44°

43'

42 c

41°

Adirondack 

Mountains VERMONT

EXPLANATION

 Basin boundary 

Hudson Valley

Mohawk Valley

Adirondack Mountains 

laconic Highlands

Appalachian Plateau

Great Lakes Plain, 

Tug Hill Rateau

Hudson Highlands, 

Manhattan Hills, 

Triassic Lowlands

0 10 20 30 40 50 MILES

I I I I I I

I Tl I I 1

0 10 20 30 40 50 KILOMETERS

\

NEW JERSEY

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 1C. Ecozone boundaries in the Hudson River basin in New York and adjacent States. (Modified from 

Will and others, 1982, fig. 2)

6 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
76' 75' 74 £ 73°

Adirondack 

Mountains

EXPLANATION

 Basin boundary

Clastic

Crystalline

Carbonate

VERMONT

0 10 20 30 40 50 MILES

I I I I I I

I i n r i i

0 10 20 30 40 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 1D. Figure 1D. Generalized bedrock geology in the Hudson River basin in New York and adjacent States. 

(Modified from Hammond and others, 1978.)

Hudson River basin 7
76" 75 c 74° 73°

44"

43'

42 c

41'

Adirondack 

Mountains

EXPLANATION

 . .. Basin boundary

Province or 

section boundary

PROVINCES AND THEIR SECTIONS

Adirondack

1 Adirondack

Ridge and Valley

2 Hudson Valley

Appalachian Plateau

3 Mohawk Valley

4 Southern New York

5 Catskill Mountains

New England

6 New England Upland

7 Taconic Mountains

8 Green Mountains

Piedmont

9 Redmont Lowlands

0 10 20 30 40 50 MILES

I I I I I I

I i n r i 1

0 10 20 30 40 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000,1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 1 E. Generalized physiographic province boundaries in the Hudson River basin in New York and adjacent 

States. (Modified from Fenneman, 1938, plate 1.)

8 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
The lower Hudson subbasin, in the south-central 

part of the study area, occupies almost 40 percent of 

the study area (fig. 1A, table 1). It is mainly in the 

Hudson River valley but extends into the Appalachian 

Plateau, Taconic Highlands, Hudson Highlands, 

Manhattan Hills, and Triassic Lowlands (fig. 1C). 

Major rivers include the Hudson River (which is tidal 

south of Albany) and Roeliff Jansen Kill, Wallkill 

River, and Rondout Creek. About 55 percent of the 

land is forested, 29 percent is farmed, and 13 percent 

is urban (table 1). The agricultural land is mainly 

within 20 mi of the Hudson River and in the Wallkill 

River basin. Urban areas include New York City, 

Albany, Poughkeepsie, and Newburg, all of which are 

on the Hudson River. Much of the subbasin is underlain by clastic rocks mostly shale and sandstone (fig. 

1C), and relief is greatest in the Catskill Mountains 

and the Hudson Highlands 

(figs. IE and 1C).

Precipitation and Runoff

The distribution of precipitation and runoff in the 

Hudson River basin is related to relief. The largest 

precipitation amounts, in excess of 50 in/yr, fall in 

(1) the upper elevations of the Taconic Highlands, 

the Adirondack Mountains, and the Catskill 

Mountains, (2) in small areas on the northwestern 

edge of the Mohawk River subbasin, and (3) in the 

southeastern part of the study unit near the Atlantic 

Ocean (fig. 2A) (Randall, 1996). The smallest 

amounts (less than 40 in/yr) fall in the low-lying 

areas next to the Mohawk and Hudson rivers. Runoff 

patterns also largely correspond to relief. For 

example, the greatest runoff (in excess of 30 in/yr) is 

in the Adirondack Mountains, Taconic Highlands, 

and the Catskill Mountains (fig. 2B); the smallest 

amounts (less than 22 in/yr) are in low-lying areas 

along the Mohawk and Hudson Rivers (Randall, 

1996).

Seasonal and annual patterns of runoff in the 

Hudson River basin were calculated from daily 

discharge data from the Mohawk River at Cohoes 

and Wappinger Creek near Wappinger Falls (fig. 1 A) 

obtained from the NWIS database of the USGS. In 

general, seasonal and yearly fluctuations in monthly 

and annual discharge from the Mohawk River at 

Cohoes, which drains more than 3,400 mi2, are 

typical of conditions in larger rivers in the northern 

part of the study unit, and those of Wappinger Creek

near Wappingers Falls, which drains about 180 mi2, 

is typical of smaller rivers in the south-central part of 

the study unit. A statistical summary of daily 

discharge on a monthly basis for these two stations is 

shown in figure 3A; annual mean discharges are 

given in figure 3B.

The median monthly discharge of the Mohawk 

River at Cohoes for 1929-91 ranges from less than 

2,000 ft3/s in August to over 10,000 ft3/s in April 

(fig. 3A). Discharge typically increases from 

October through December, as temperatures 

decrease and the growing season ends. Discharges 

for January and February, when temperatures decline 

and much of the precipitation falls as snow, are 

typically lower than those for December; and median 

daily discharge typically peaks in March and April, 

during spring snowmelt. Discharges generally 

decline from May through August as snowmelt 

ceases and temperatures and infiltration increase.

The median monthly discharge of Wappinger 

Creek near Wappingers Falls for 1929-91 ranges 

from less than 30 ft3/s in September to more than 400 

ft3/s in March (fig. 3A). Unlike the Mohawk River 

discharge at Cohoes, Wappinger Creek discharge 

near Wappingers Falls increases from October 

through March and generally does not decline during 

January and February; it generally is highest in 

March and declines from April through September. 

The seasonal differences in discharge between these 

two sites are related to climatic differences between 

the two drainage basins. Wappinger Creek is in the 

southern part of the study unit, which is less 

mountainous than the Mohawk River watershed and, 

thus, has generally warmer winters. Therefore, 

discharge in Wappinger Creek does not decrease 

during January and February, and spring snowmelt 

generally occurs in March.

Annual mean discharges for the Mohawk River at 

Cohoes and Wappinger Creek near Wappingers Falls 

for 1970-90 indicate that annual mean discharge in 

the early- to mid-1970s was higher than that for 1929- 

91; annual mean discharge of the Mohawk River 

exceeded the average for 1929-91 in each of the 9 

years from 1971 through 1979. The highest annual 

mean annual discharge of the Mohawk River at 

Cohoes was recorded in 1972, and the second highest 

was in 1976. Flow conditions returned to normal after 

1979, and the annual mean discharge exceeded the 

average for 1929-91 less than half the time.

Hudson River basin 9
76' 75' 74 c 73 c

44

43'

41 C

Adirondack 

Mountains VERMONT

EXPLANATION

 - Basin boundary

Line of equal mean 

annual precipitation, 

1951-80. Interval is 

4 inches from 38 to 

50 inches, 5 inches 

above 50 inches.

-42-

0 10 20 30 40 50 MILES

I I I I I I

I I I I I I

0 10 20 30 40 50 KILOMETERS

C a t s k i II

55

Mountain 

60

/

\

rJ NEW JERSEY

Base from U.S. Geological Survey digital data 1:2,000,000,1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 2A. Mean annual precipitation in the Hudson River basin in New York and adjacent States. 

(Modified from Randall, 1996.)

10 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
76' 75 c 74° 73 c

Adirondack 

Moun VERMONT

EXPLANATION

 Basin boundary

Line of equal mean 

annual runoff, 1951-80. 

Interval is 4 inches 

from 16 to 30 inches, 

5 inches above 30 

inches.

-26-

0 10 20 30 40 50 MILES

I I I I I I

I Tl 1 I I

0 10 20 30 40 50 KILOMETERS

\

rJ

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45 ° 30', central meridian -74°

Figure 2B. Mean annual runoff in the Hudson River basin in New York and adjacent States. (Modified from Randall, 1996.)

Hudson River basin 11
100

u_ 

O 

co Q

isa y

E I I I I I I I I I I I T 

I MOHAWK RIVER AT COHOES, 1929-91

0.1 I I I I I I I I I I I I

10

ONDJFMAMJJAS

0.1

0.01

0.001

I I l r

WAPPINGER CREEK NEAR WAPPINGERS 

FALLS, 1929-91

I I I I I I I I I I I

EXPLANATION

Percentile 

 90

75

50

25

10

MONTH

A. MONTHLY MEANS

THOUSANDS DISCHARGE, IN OF PERSECOND CUBIC FEET 

Ol *» CM00 

MOHAWK F

/ i

t *

\

RIVER NEAR COHOES

,-, Mean anni 

/ / for 1929-9

I I

,1970-90

jal discharge 

1

7

1

5

-

1

ONDJFMAMJJAS 

MONTH

0.5

0.4 -

0.3 - n

0.2 -

0.1 -

WAPPINGE 

. FALLS, 197

7

-/////

iR CREEK NEAR VW 

0-90

Mean annual d 

for 1929-91

EL \

ihs.\ ;

SPRING 

ischarge

/ /

ER£

n

/ /

7 

/ 

/

1970 1975 1980 

YEAR

1985 1990 1970 1975 1980 

YEAR

1985 1990

B. ANNUAL MEANS

Figure 3. Mean flows of Mohawk River at Cohoes, N.Y. and Wappinger Creek near Wappingers Falls, N.Y. 

A. Monthly mean discharge, by month, 1929-91. B. Annual mean discharge, 1970-90

Aquifers

All significant aquifers in the Hudson River basin 

consist of unconsolidated glacial deposits or bedrock. 

Unconsolidated deposits of thick sand and gravel 

underlie flood plains and terraces along the larger tributaries to the Hudson River and occupy many valleys 

(fig. 4). Ground water in valley-fill aquifers can be in 

hydraulic connection with overlying streams but can be 

confined locally. Induced infiltration from streams to 

underlying aquifers commonly occurs where pumped 

wells are close to the streams (Waller and Finch, 1982). 

In some areas, particularly in Albany, Schenectady, and 

Saratoga Counties, sand deposits derived from glaciallake sand and beach sand form significant aquifers. 

Four aquifers in the Hudson River basin are designated 

as Primary-Water-Supply Aquifers by the New York 

State Department of Environmental Conservation 

(NYSDEC); they are Fishkill/ Sprout Creek aquifer, 

Clifton Park/Halfmoon aquifer, Croton-on-Hudson 

aquifer, and the Schenectady aquifer (New York State 

Department of Health, 1981). The Schenectady aquifer 

is also designated as a sole-source aquifer by the 

USEPA (New York State Department of Health, 1981). 

All shallow, unconfined unconsolidated aquifers 

(water-table aquifers) are highly susceptible to contamination from surface sources.

12 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
76' 75 c 74° 73 c

Adirondack 

Mountains

EXPLANATION

 Basin boundary

Unconsolidated 

aquifers

0 10 20 30 40 50 MILES

I I I I I I

I I \ T I 1

0 10 20 30 40 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000,1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45 ° 30', central meridian -74°

Figure 4. Locations of unconsolidated aquifers in the Hudson River basin in New York and adjacent States. 

(Modified from Bugliosi and others, 1988 and Bugliosi and Trudell, 1988a, 1988b.)

Hudson River basin 13
Bedrock aquifers in the study unit consists of 

consolidated clastic (sandstone and shale) and 

carbonate (limestone and dolomite) rocks, some of 

which have been metamorphosed (fig. 1C). Groundwater movement in bedrock aquifers is principally 

along secondary openings such as fractures or 

bedding planes. The shales in much of the study area 

generally form aquifers that are adequate for domestic 

water supply (Hammond and others, 1978; Rogers, 

1988).

Reservoirs

Major rivers of the Hudson River basin contain 

several reservoirs, dams, and locks. These structures 

store sediment as well as river water and thereby 

affect the movement of nutrients and sediment in the 

basin. All of the large reservoirs in the basin are in 

areas dominated by forests and, therefore, would not 

be expected to receive large amounts of nutrients or 

sediments because these are derived mostly from 

agricultural or urban areas. Regulation by dams and 

diversion of flows could decrease nutrient and 

sediment yields downstream, however.

Upper Hudson Subbasin

Major reservoirs in the upper Hudson subbasin 

include Great Sacandaga Lake and Indian Lake 

(fig. 5). Great Sacandaga Lake impounds flow from 

the uppermost 1,044 mi2 of the Sacandaga River, and 

Indian Lake impounds flow from the uppermost 

131 mi2 of the Indian River basin. These reservoirs 

store water for flood control, low-flow augmentation, 

and power generation. Great Sacandaga Lake has a 

usable capacity of 29.7 billion ft3 , and Indian Lake 

has a usable capacity of 4.7 billion ft3 . These capacities represent about 12 in. of runoff at Great Sacandaga Lake and about 15 in. of runoff at Indian Lake. 

These reservoirs probably receive and store only 

small amounts of nutrients and sediment, however, 

because their mean annual inflow is small relative to 

their total capacity and because they are in extensively forested areas.

Mohawk River Subbasin

The Mohawk River subbasin contains three major 

reservoirs -Schoharie Reservoir, Hinckley Reservoir, 

and Delta Reservoir (fig 5). Schoharie Reservoir 

receives discharge from the uppermost 315 mi2 of the 

Schoharie Creek watershed and has a usable capacity

of 2.62 billion ft3 ; this represents about 3.6 in. of 

runoff. All stored water is diverted from Schoharie 

Reservoir to Esopus Creek for the New York City 

water supply, except in periods of uncontrolled spillage. The annual mean diversion for 1992 was 

475 ft3/s. The diversion of water from Schoharie 

Creek probably has little direct effect on nutrient and 

sediment concentrations in Schoharie Creek because 

much of the watershed above Schoharie Creek is 

forested; yet, by decreasing discharge, the diversion 

could decrease the transport of nutrients and sediment 

in the watershed.

Hinckley Reservoir receives flow from the uppermost 372 mi2 of West Canada Creek (fig. 5) and has 

a usable storage capacity of 3.3 billion ft3 ; this capacity equals 3.8 in. of runoff. Minor amounts of water 

are diverted from Hinckley Reservoir for municipal 

water use in Utica. Delta Reservoir receives flow 

from the upper 148 mi2 of the Mohawk River (fig. 5) 

and has a usable storage capacity of 2.8 billion ft3- 

about 8.1 in. of runoff. Minor amounts of water are 

diverted from Delta Reservoir for canal navigation 

purposes (Firda and others, 1993). About 25 percent 

of the watershed draining to Delta Reservoir is 

agricultural; thus, the reservoir could decrease nutrient and sediment concentrations in downstream parts 

of the Mohawk River.

Lower Hudson Subbasin

The lower Hudson subbasin contains two major 

reservoirs-Ashokan and Rondout Reservoirs (fig. 5), 

both of which are in highly forested headwater areas. 

Ashokan Reservoir, which lies in the uppermost 256 

mi2 of the Esopus Creek watershed, receives flow 

from Esopus Creek plus diverted waters from 

Schoharie Creek and has a usable capacity of 17.1 

billion ft3-equal to more than 25 in. of runoff. The 

annual mean diversion of water from Ashokan Reservoir to the New York City water-supply system for 

1992 was 886 ft3/s (Firda and others, 1993).

Rondout Reservoir drains the uppermost 95.4 mi2 

of the Rondout Creek watershed (fig. 5) and has a 

usable capacity of 6.68 billion ft3-more than 25 in. of 

runoff. Rondout Reservoir receives water diverted 

from three other reservoirs in the upper reaches of the 

Delaware River. The annual mean diversion from 

Rondout reservoir to the New York City water-supply 

system in 1992 was 1,101 ft3/s (Firda and others, 

1993).

14 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
76' 75 c 74° 73°

Adirondack 

Mountains VERMONT

(\

) r^' Delta t»-i ^jT^ J/

1 Reservoir "*<^"^~ ..

EXPLANATION 

^ ..-^.. Basin boundary

Reservoir or lake

0 10 20 30 40 50 MILES

I I I I I I

I Tl I I I

0 10 20 30 40 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 5. Locations of major reservoirs in the Hudson River basin in New York and adjacent States.

Hudson River basin 15
Water Use

Treated wastewater can be a significant source of 

nitrogen and phosphorus inputs into surface-water 

bodies in the Hudson River basin. Public-supply 

withdrawals become treated wastewater and, thus, 

can affect the concentration and movement of nutrients within the basin.

Total ground-water and surface-water withdrawals 

for water supply in the Hudson River basin in 1985 

were about 1 Bgal/d (table 2) (Solley and others, 

1988). Nearly 90 percent of the withdrawals for 

public water supply are from surface water; the vast 

majority of households not served by public water 

supply use ground water. Rates of total industrial 

withdrawals in 1985 were about 400 Mgal/d; two 

thirds of the water was surface water. Withdrawals for 

electric power generation from the estuarine part of 

the Hudson River exceed 2 Bgal/d, two-thirds of 

which are for cooling in nuclear powerplants; the 

remaining third is used for cooling in fossil-fuel 

thermoelectric plants.

Pesticide Use

Estimated application rates of commonly used 

pesticides enable comparison of pesticide use with 

pesticide concentrations in ground water, surface 

water, and streambed sediment. This comparison can 

help identify locations at which future collection of 

ground-water, surface-water, and streambedsediment samples for pesticide analysis should be 

focused. Estimates of the application rates are available for two types of pesticide compounds in the 

Hudson River basin-persistent organochlorine cornTable 2. Estimated water use in the Hudson River basin 

in New York and adjacent States, 1985.

[Data from U.S. Geological Survey Aggregated Water Use Data 

System. All values are in millions of gallons per day. Dashes 

indicate no data].

Use

Water Supply 

Commercial

Domestic

Industrial

Fossil Fuel

Nuclear Power

Mining 

Livestock

Irrigation

Fresh 

Ground 

water

73.3 

9.44

65.8

110

.

-

2.27

1.53

Surface-water 

Withdrawals

Fresh Saline

926

25.4 -

-

201

1280 726

1480

27.3 - 

1.22

6.57

Consumptive 

Use

Freshwater

17.3

45.8

70.0

12.8

-

2.73 

3.13

8.10

Saline 

Water

-

-

-

7.26

1340

-

-

pounds (including chlordane and DDT [dichlorodiphenyltrichlorethane]) that were widely used 20 or 

more years ago, and compounds that have been in 

wide use since 1980, including atrazine, alachlor, 

metiram, methyl parathion, cyanazine chlorothalonil, 

carbaryl, metolachlor, carbofuran, and 2,4-D ([2,4- 

dichlorophenoxy] acetic acid). Rod (1989) estimated 

chlordane and DDT applications from data compiled 

by Ayres and others (1988). National average rates of 

pesticide application, as estimated by Ayres and 

others (1988) from pesticide-export data, were apportioned to agricultural areas on the basis of crop 

acreage, and to urban and forested lands according to 

the land-use acreage, by subbasin.

Gianissi and Puffer (1988) used 1986 national 

estimates of pesticide-application rates, by crop type, 

in conjunction with county estimates of crop acreage, 

to estimate application rates, by county, for a variety 

of pesticides, including atrazine, alachlor, metiram, 

methyl parathion, cyanazine, chlorothalonil, carbaryl, 

metolachlor, carbofuran, and 2,4-D. Their results do 

not include pesticide applications in urban or forested 

areas; thus, the application rates estimated for 

compounds such as carbaryl that are widely used for 

insect control on lawns (Ware, 1989) could be 

substantially lower than the actual rates.

DDT-application patterns differed from chlordaneapplication patterns across the Hudson River basin, 

DDT was applied in a wide variety of settings, including urban, agricultural, and forested areas (Rod, 

1989). In urban areas it was used to control a variety 

of insects; in agricultural areas it was used to control 

insects on potatoes, vegetables, and orchards; and in 

forested areas it was used to control gypsy moth and 

blackfly populations. Use of DDT in the Hudson and 

Raritan River basins peaked in 1957 and subsequently 

decreased until the compound was banned in the early 

1970's (fig. 6A). This report gives the combined 

applications for both River basins because Rod 

(1989) did not calculate separate annual application 

estimates for the Hudson River basin. The peak DDT 

use in 1957 reflects a short-term increase in DDT use 

within forested areas in the Adirondack Mountains. 

Overall, DDT use in the Hudson and Raritan River 

basins during the 1950's and 1960's was highest in 

the Mohawk River subbasin and the northernmost 

parts of the lower Hudson subbasin.

Chlordane was applied in fewer types of settings 

than DDT in the Hudson River basin; it was largely 

used for the control of termites and other insects in 

suburban and urban settings and was used only to a

16 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
1000

100

10

DOT

DOT use banned 

in 1972

1940 1950

A. DOT, BY Year

1960 1970 1980

"8

tr Q 

LJ _i

70

60

50

40

30

20

10

0

DOT

Urban Agricultural Forest 

B. DOT, BY LAND USE

1000

100

10

CHLORDANE

1940 1950 1960

C. CHLORDANE, BY Year

1970 1980

Figure 6. Estimated pesticide application in Hudson River 

basin, N.Y., and Raritan River basin, N.J., 1940-80. A. DOT 

application rate, by year. B. DOT application, by land-use 

category. C. Chlordane- application rate, by year. (Modified 

from Rod, 1989, figs. 8-6 and 8-4.)

small degree in agricultural and forested areas (Rod, 

1989). Chlordane use in the Hudson and Raritan 

River basins increased steadily from 1945 to about 

1972, then declined sharply during 1973-78 (fig. 6C). 

The areas with large populations, such as the southernmost part of the lower Hudson subbasin, had the 

highest chlordane use; chlordane use in areas 

dominated by agricultural or forested, land such as the 

Schoharie Creek watershed and the Adirondack 

Mountains, was almost negligible (Rod, 1989).

Of the 10 most extensively used agricultural pesticides, the two that were applied at the highest rates in 

1986 (table 3) were atrazine a triazine herbicide 

(Ware, 1989), and alachlor-an acetanelite herbicide 

(Ware, 1989). The patterns of atrazine and alachlor 

use are generally similar to those of four other widely 

used pesticides -cyanazine, metolachlor, carbofuran, 

and 2,4-D. In general, the greatest use of these pesticides is in the Mohawk Valley and Hudson Valley 

ecozones (fig. 1C); for example, the largest applications of atrazine and alachlor were in Washington, 

Columbia, Madison, and Montgomery Counties, N.Y. 

(fig. 7). The general application patterns for carbaryl, 

a carbamate compound used as an insecticide (Ware, 

1989), are similar to those for metiram, a dithiocarbamate used as a fungicide (Ware, 1989), and methyl 

parathion, a phenyl derivative used as an insecticide 

(Ware, 1989). The highest rates of carbaryl application are in Columbia and Ulster counties (fig. 7). The 

highest application rates of chlorothalonil, a substituted aromatic used as a fungicide, are in the lower 

Hudson subbasin (fig. 7).

Table 3. Estimated agricultural use of selected pesticide 

compounds in the Hudson River basin, N.Y., and adjacent 

States, 1986.

[Units in thousands of pounds. Data from Gianissi and Puffer, 

1988.]

Pesticide

Atrazine

Alachlor

Metiram

Methyl 

Parathion

Cyanazine

Application 

Rate

257

177

164

141

90.7

Application 

Pesticide Rate

Chlorothalonil

Carbaryl

Metolachlor

Carbofuran

2,4-D

62.2

60.6

56.8

53.6

50.0

Pesticide Use 17
I 

aWo

3

 a 

n>a

o a(0 03

a. v>

I(0

I

44'

43'42'

76 s

A. ALACHLOR

75'

Adirondack

74° 73 C

I I I I I I

0 50 KILOMETERS

EXPLANATION

Basin boundary

_._._ County boundary Catskm

APPLICATION RATE, IN

POUNDS PER SQUARE MILE Mountai

[ | Less than 6.0 /> 

If 111111 6.0 to 11.9

^ Hj Greater than 18.0

50 MILES

i ' '

Base from U.S. Geological Survey digital data 1:2,000,000,1972 Albers Equal-Area Conic projection. Standard parallels 29*30' and 45*30', central meridian -74°.

44'

43'

42'41

76'

. B. ATRAZINE

75'

Adirondack

74° 73°

VERMONT

EXPLANATION

Basin boundary

 - County boundary

APPLICATION RATE, IN 

POUNDS PER SQUARE MILE

[ | Less than 10.0

[i jasi^j 10.0 tO 19.9

^ Hj Greater than 30.0

50 MILES

i i i

50 KILOMETERS NEW JERESY

Base from U.S. Geological Survey digital data 1:2,000,000,1972 Albers Equal-Area Conic projection. Standard parallels 29*30' and 45*30', central meridian -74*.

Figure 7. Estimated 1988 rates of pesticide application in the Hudson River basin in New York and adjacent States, by county. 

(Data from Gianissi and Puffer, 1988.): A. Alachlor. B. Atrazine. (County names are shown in fig. 1B.)
76" 75° 74° 73° 76° 75° 74 c 73°

44'

_ C. CARBARYL

43 e42'

EXPLANATION

 .. Basin boundary

County boundary Catskm

APPLICATION RATE, IN

POUNDS PER SQUARE MILE Mountajns

| | Less than 1.0[.^..^.' |g;|| 1.0 tO 1.9

Ulllll Greater than 3.0 

50 MILES

ill i i 

I I I T

50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2.000,000,1972 Albers Equal-Area Conic projection. Standard parallels 29° 30' and 45° 30', central meridian -74*.

44 e43 e

42'

41

D. CHLOROTHALONIL

Adirondack V' 

Mountains

EXPLANATION

Basin boundary

 - County boundary

APPLICATION RATE, IN

POUNDS PER SQUARE MILE Moun{ains

| | Less than 0.25 

psssis;"| 0.25 to 0.49

^^^H Greater than 0.75

0 50 MILES

i i i i i i I r~i r I i 

0 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000,1972 Albers Equal-Area Conic projection. Standard parallels 29*30' and 45*30', central meridian -74°.

Figure 7. Estimated 1988 rates of pesticide application in the Hudson River basin in New York and adjacent States, by county. 

(Data from Gianissi and Puffer, 1988.): C. Carbaryl. D. Chlorothalonil. (County names are shown in fig. 1B.)
WATER-QUALITY ASSESSMENT

Basinwide assessment of ground-water and 

surface-water quality in the Hudson River basin 

began with a compilation and evaluation of available 

chemical and ancillary data. The data on most 

constituents discussed herein are derived from USGS 

studies, and most of the data are suitable for a basinwide comparisons because the samples were 

collected and analyzed by uniform methods. Data 

from some non-USGS studies are included where 

appropriate to provide additional information on 

spatial, temporal, or other trends in nutrient or pesticide concentrations.

Approach

The analyses of available ground-water and 

surface-water quality data in this report are based 

mostly on data available in the NWIS database. These 

data were collected through cooperative studies 

between the USGS and several State and local 

agencies. USGS data were used because they (1) are 

available in computerized form, (2) can be associated 

with a geographic location, and (3) are from sites for 

which hydrologic, geologic, and other ancillary data 

are available.

Ground-Water Data

The ground-water data used in this report represent the results of projects in many areas and at 

differing spatial scales. Because quality-assurance 

data were not routinely collected as part of these 

investigations, the quality of the data is not quantifiable. Where more than one sample was available 

from a given well, only the most recent analysis for a 

given constituent was used, to avoid biasing data 

toward sites with multiple analyses. The assessment 

of ground-water quality is limited to dissolved nitrate 

and selected pesticides and VOCs (volatile organic 

compounds) in water from wells for which information on well depth and aquifer type was available.

Sites from which ground-water-quality data were 

available are classified in this report according to 

aquifer material, well depth (for screened and openend wells), and land use in the well-site vicinity. 

Samples from unconsolidated aquifers represented in 

this report include those obtained from wells finished 

in unconsolidated aquifers, and samples from 

bedrock wells include those obtained from wells

finished in bedrock aquifers, typically open-hole 

wells cased to competent bedrock. Data on well 

location, aquifer material, and well depth were 

obtained from the NWIS data base and were not field 

checked. Sites were classified as urban, agricultural, 

or forested, depending on the predominant land use 

within 1/2-mi radius of the well. The land-use 

category for each site was determined by overlaying 

digital land-use coverages (U.S. Geological Survey, 

1979a,b,c,d; 1980a,b) on a digital coverage of well 

locations. The land-use data were not field checked.

Surface-Water Data

A variety of procedures described below were 

used to compile surface-water quality data and ancillary watershed data within the Hudson River basin.

Site Selection

Most of the nutrient and suspended-sediment 

analyses presented in this report are based on data 

collected at sites with daily discharge records. Most 

sites selected have dissolved nitrate, total nitrogen, 

or total phosphorus data for more than 25 samples. 

The availability of daily discharge data at these sites 

enables determination of: (1) the availability of 

water-chemistry data over the range of flow conditions, (2) the relation between concentration and 

discharge, and (3) solute- and sediment-transport 

rates at these sites. Discharge data for some ungaged 

sites were calculated from the discharge record of a 

nearby gaged site by multiplying the discharge at the 

gaged site by a ratio equal to the drainage area of the 

ungaged site, divided by the drainage area of the 

gaged site. Some sites that lack daily discharge data 

have 10 or more samples with dissolved nitrate, total 

nitrogen, or total phosphorus analyses; these sites 

were included in the analysis of nutrient concentrations in relation to land use.

Data from any two sites that were near one 

another were generally interpreted as one site. Nutrient data from stations whose drainage-area size was 

within 5 percent of a different station's drainagearea size were compared; if the data were similar, 

they were assigned to the station with the majority of 

data. This 5-percent criterion was used because a 

few sites with differing station-identification 

numbers in the NWIS database represent data from 

essentially the same site. Exceptions were nutrient 

samples from the Hudson River at Corinth, Glens

20 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
Falls, and Fort Edward; data for these three sites 

were not combined because Glens Falls, between 

Corinth and Fort Edward, is the first substantial 

urban area through which the Hudson River flows. 

Another exception was made for samples from two 

sites near the outlet of the Mohawk River-the 

Mohawk River at Crescent Dam and the Mohawk 

River at Cohoes. Samples from the Crescent Dam 

site were collected at the hydroelectric station 2.4 mi 

upstream from the Cohoes site. The effect of this 

difference in sampling location is unknown because 

few simultaneous samples were collected. The 

Crescent Dam site was included in this analysis 

because more than 90 percent of the data collected at 

the outlet of the Mohawk River were collected there.

Water-quality data from selected sites without 

daily discharge records were used with data from 

sites with daily discharge data in this study to make 

broad comparisons of median nutrient, suspendedsediment, and pesticide concentrations among sites 

that differ in land use, population density, and 

geologic characteristics. To avoid biasing the 

comparison of nutrient and pesticide concentrations 

among sites, data from sites with overlapping drainage areas were included only if no more than 50 

percent of their drainage areas overlapped.

Data Sources

Most of the surface-water nutrient data analyzed 

in this report are from the NWIS database. Nutrient 

data from four sites in New Jersey were analyzed by 

the NJDEP (New Jersey Department of Environmental Protection), Division of Water Resources laboratories (Bauersfield and others, 1988) and stored in 

the USGS database. (The NJDEP sites were included 

because they represent urban watersheds, without 

which the comparison of median nutrient concentrations would have represented only one urban site). 

Discussions of temporal trends in nutrient and pesticide concentrations in surface water of primarily 

forested watersheds in the Hudson River basin are 

based on data collected by the NYCDEP (New York 

City Department of Environmental Protection ); 

these data represent the only two sites in the Hudson 

River basin with long-term (greater than 30 years) 

water-quality records. Time trends for these data are 

reported by Murdoch and Stoddard (1992).

Suspended-sediment data represent sites from 

which 20 or more analyses were available in the 

NWIS system. Of those sites, only the ones for which

daily discharge records were available were used to 

calculate sediment yield.

The pesticides discussed in this study are those 

with NWIS data from 10 or more sites and the three 

reported by Bopp and others (1982) from the lower 

Hudson River.

Methods of Analysis

A variety of maps, graphs, and nonparametric 

statistics are used in this report to depict the availability and statistical characteristics of nutrient, 

suspended-sediment, and pesticide concentrations 

and nutrient and sediment yields in streams of the 

Hudson River basin. The maps depict the spatial 

distribution of sites used for analysis. Bar charts 

depict the avail-ability of nutrient and sediment data 

for selected analyses by month, year, and percentile 

of flow. Maps and tables indicate the availability of 

pesticide data in streambed sediments and water 

samples over space and time.

The statistical range of nutrients, sediment, and 

pesticide concentrations at sites is depicted in 

boxplots and tables, and detection rates for pesticides 

are summarized in barcharts. Relations between 

concentration and discharge for nutrients and 

sediment are indicated by LOWESS (locally 

weighted scatterplot smooth) lines (Helsel and Hirsh, 

1992). Statistical tests of trends over space and 

through time were done through nonparametric tests 

of association. Temporal trends in concentrations 

reported by Murdoch and Stoddard (1992) for two 

streams in the Catskill Mountains used analysis of 

covariance on ranks.

Median nutrient, sediment, and pesticide concentrations are compared among sites with differing land 

use through nonparametric tests of association, 

including Kruskall Wallace, Mann-Witney, and 

Tukey tests. Relations between nutrient concentrations and land use are depicted by nonparametric tests 

of association, including Spearman-rank correlations.

Yields of nutrient and sediments were calculated 

through a program that uses a minimum variance 

unbiased estimator (Cohn and others, 1989; Gilroy 

and others, 1990). The nutrient loads in this report are 

based on data for two periods-1970-80 and 1981-90- 

because concentration data were available from only 

certain periods. Loads for each of these periods were 

calculated from five variables-a constant, the log of 

instantaneous flow, the log of instantaneous flow

Water-Quality Assessment 21
squared, and the sine and cosine of the day of the year. 

Where instantaneous flow data were unavailable, 

mean daily discharge was used to estimate flow. 

Sediment loads for sites with daily sediment values 

were estimated through the program for days with 

missing data.

Because data availability is uneven, and flow 

conditions transient, transport yields in this report are 

reported as an average of 3 years representing a wide 

range of flows-one in which the annual mean flow 

was ranked in the upper 10 percent of the annual mean 

flows, one in which the annual mean flow was equal 

to the mean annual flow, and one in which the annual 

mean flow was ranked in the lower 10 percent of the 

annual mean flows. This averaging of transport rates 

over high, medium, and low-flow conditions 

improves the reliability of comparison of transport 

rates among stations. Sediment-transport rates also 

are reported for 1978, a year with high annual mean 

flow at most of the sites from which suspendedsediment data are available.

Ancillary Data

Ancillary data from a variety of sources 

(described below) were used in this study to obtain 

quantitative estimates of environmental factors and 

nutrient- and pesticide-application rates in the 

watersheds of selected sites. Environmental factors 

include geology, land use, population, rate of manure 

and fertilizer application, and rate of atmospheric 

deposition. Environmental factors were quantified by 

overlaying digitized watershed boundaries on digital 

coverages of ancillary data. Boundaries of most 

watersheds were delineated in this report by a 

1:250,000-scale DEM (digital elevation model), and 

accuracy was checked through a comparison of the 

drainage area of the DEM-generated boundary with 

the drainage area recorded in files of the Troy, N.Y. 

office of the USGS. All drainage areas delineated by 

the DEM differed by less than 5 percent from those 

on record. Some of the watershed boundaries, 

particularly those for watersheds smaller than 20 

mi2, were manually digitized from 7.5-minute 

topographic maps.

Land Use. Estimates of land use were made by 

overlaying the digitized basin boundaries on 

digitized land-use coverages compiled at a scale of 

1:250,000 (U.S. Geological Survey, 1979a, b, c, d; 

1980a, b). These data are based on high-altitude areal

photographs taken during 1970-78 and, thus, represent land-use conditions of the 1970's and might not 

reflect present land-use conditions, especially in 

small watersheds near large urban areas. This generally should not be an obstacle in relating surfacewater quality to land use patterns, however, because 

most of the available surface-water-quality data were 

collected during 1970-81. Estimates of geologic 

characteristics of watersheds are based on a digitized 

map compiled by Hammond and others (1978) at a 

scale of 1:500,000. The percentages of each watershed that are underlain by clastic (sandstone and 

shale), crystalline rock, and carbonate rock were 

obtained by a method similar to that used to determine land use. Basin-population estimates were 

obtained from digitized coverages of the centers of 

U.S. Census tracts; the population of a basin is the 

sum of populations of all the census tracts with 

centers within the watershed boundary.

Nutrient-In put Rates. Estimated rates of nitrogen and phosphorus input from fertilizer, manure, 

treated-waste water sources, and atmospheric deposition are based on varied data sources and time 

periods but represent the best available data and 

allow national comparisons of nitrogen- and 

phosphorus-input rates. Average fertilizer-application rates during 1970-79 were obtained from 

Alexander and Smith (1990) and are based on USDA 

(U. S. Department of Agriculture) Census of 

Agriculture data for county-level estimates of fertilized acreage. Average fertilizer-application rates for 

1986-91 were estimated by W. Battaglin (U.S. 

Geological Survey, written commun., 1992) and are 

based largely on county-level fertilizer estimates 

calculated by USEPA (1990) from crop data. The 

fertilizer-application rates for 1970-79 used in this 

report are average yearly applications for 1970-79; 

similarly, the application rates used for 1986-90 

represent average yearly applications for 1986-90. 

Manure-application rates are based on USDA 

Census of Agriculture data on livestock populations, 

by county, and were computed by W. Battaglin (U.S. 

Geological Survey, written commun., 1992) for 

1982 and 1987. Fertilizer- and manure-application 

rates for the watershed for each site were calculated 

by first obtaining the rate of agricultural fertilizer or 

manure application (equal to the total amount of 

fertilizer or manure applied in a county, divided by 

the cropland plus pastureland acreage in the county),

22 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
and multiplying the result by the number of acres of 

agricultural land use in a county that lies within the 

specified watershed. The sum of this product overall 

counties within the watershed yielded the total fertilizer or manure application of nitrogen or phosphorus 

for the watershed.

Inputs of nitrogen and phosphorus from treated 

wastewater are calculated from estimates of designcapacity flow from sewage-treatment plants. The 

discharge capacities estimated for New York State 

were based on data from NYDEC (1987); estimates 

for New Jersey, Massachusetts, and Vermont were 

based on the Permit Compliance System files 

compiled by USEPA. Estimates of treated-wastewater discharge from New York State plants were 

modified by D. S. Lumia (U.S. Geological Survey, 

written commun., 1993) and are on file at the USGS 

office in Troy, N.Y. Estimated inputs of nitrogen and 

phosphorus from treated wastewater were based on an 

average concentration of 15.1 mg/L for nitrogen and 

11.1 mg/L for phosphorus; these values are typical for 

primary treated effluent (National Oceanic and 

Atmospheric Administration, 1993).

Rates of atmospheric deposition of nitrogen were 

estimated from precipitation-chemistry data collected 

at six sites by the National Atmospheric Deposition 

Program (NADP, 1992). These estimates were 

adjusted for dry deposition in the northeast United 

States, for wet and dry deposition in urban areas, and 

for droplet deposition for elevations above 1,850 ft 

(Sisterson, 1990). Nitrogen deposition rates discussed 

in this report are based on the annual averages for 

1984-90.

Land-Use Categories

Each surface-water site was designated as 

representing one of four land-use categories to 

correlate land use with (1) surface-water quality, and 

(2) the availability of surface-water-quality data. The 

four categories, described below, are forested, 

agricultural, urban, and mixed; together they 

represent the range of land use within the Hudson 

River basin. The criteria used to categorize surfacewater sites were (1) known correlations between 

water quality and land use, and (2) land-use 

characteristics of the Hudson River basin.

Forested watersheds are those that are more than 

78 percent forest cover and less than 18 percent 

agricultural and urban land combined. The 78-

percent criterion was selected because Murdoch and 

Stoddard (1992) found nitrate concentrations in a 

subbasin of Schoharie Creek that is about 80 percent 

forested to be unaffected by agricultural or urban 

activities. The Hudson River basin is 62 percent 

forested; therefore, the 78-percent criterion ensures 

that watersheds designated as forested have a larger 

proportion of forested land use than the Hudson 

River basin does. The second criterion-that watersheds designated as forest be less than 18 percent 

urban plus agricultural land-was used to exclude 

sites that are affected by urban or agricultural activities to ensure that the surface-water quality at sites 

representing forested watersheds reflects relatively 

pristine conditions.

Agricultural watersheds are those that are at least 

25 percent farmland and less than 11.5 percent urban 

land. The Hudson River basin is 25 percent forested; 

therefore, the 25-percent criterion ensures that watersheds designated as agricultural have a larger proportion of agricultural land use than the Hudson River 

basin does. The 11.5-percent criterion was used to 

ensure that urban land in agricultural watersheds 

would not greatly affect the water quality at monitoring sites. Water quality at sites representing agricultural watersheds should reflect the presence of fertilizers and manure.

Urban watersheds are those in which more than 7.8 

percent of the land is urban (including commercial, 

residential, and industrial land uses) and less than 20 

percent is agricultural. The Hudson River basin is 7.8 

percent urban; therefore, the 7.8-percent criterion 

ensures that watersheds designated as urban have a 

larger proportion of urban land than the Hudson River 

basin does. The criterion of less than 20 percent 

agricultural land was used to ensure that water quality 

at urban sites would not be significantly affected by 

agricultural activities and would largely reflect only 

the presence of sewage and other urban-associated 

sources of runoff.

Mixed land-use watersheds are those that did not 

match the criteria for the three preceding categories. 

Water quality at these sites would be expected to 

reflect a variety of land uses, including urban and 

agricultural activities.

Water-Quality Assessment 23
Availability of Data, 1970-90

Assessment of water-quality conditions in the 

Hudson River basin requires data that (1) provide 

adequate spatial and temporal representation, and (2) 

reflect the current environmental conditions. The 

following sections discuss the availability of recent 

(1970-90) data on (1) nutrients in ground-water and 

surface water, (2) pesticides in ground water, surface 

water, and streambed sediments, and VOCs (volatile 

organic compounds) in ground water, and on (3) 

suspended sediment in surface water, with respect to 

space and time and over a range of environmental 

conditions.

Ground Water

Data on nutrient and pesticide concentrations in 

ground water in the Hudson River basin are limited. 

Although ground-water quality data were collected at 

427 sites in the study area during 1970-90, nutrient 

and pesticide data were obtained at only 100 sites 

from which aquifer-type and well-depth information 

also are available.

Nutrients

The only nutrient discussed in relation to ground 

water is dissolved nitrate. Dissolved-nitrate analyses 

are available for 236 sites in the study area, 77 of 

which have no information on well depth or aquifer 

type, and another 59 of which have information on 

aquifer type, but not the recorded well depth. Of the 

100 sites for which well depth and information on 

aquifer material are available (table 4), 63 are classified as unconsolidated-aquifer sites, and 37 are classified as bedrock-aquifer sites. Well-depth and aquifer 

data for these wells did not include records of the 

depth to water, nor sampling-depth interval. Wells 

completed in bedrock commonly are constructed with 

casing installed to competent bedrock, then 

completed as open hole; thus, water samples from 

these wells could be a mixture of water from waterbearing zones throughout the open interval. Because 

no data on depth of casing or open intervals are available, well depth is used for comparison purposes 

only.

Sites for which ground-water quality, well-depth, 

and aquifer-type data are available are distributed 

unevenly throughout the study area (fig. 8A)- many 

are clustered in three areas-(l) Albany County, N.Y., 

(2) Berkshire County, Mass., and (3) Westchester

County, N.Y. and adjacent Fairfield County, Conn.; 

the rest are scattered across the study area. Groundwater quality data for most of the study area are 

unavailable. Statistical comparisons pertaining to 

aquifer type in this report are based on data from two 

areas -Albany County (unconsolidated aquifers) and 

Westchester County (bedrock aquifers).

The land use attributed to each well site is the 

dominant land use within a 1/2-mi radius of the well. 

By this criterion, 53 of the 100 sites are urban, 20 are 

agricultural, and 27 are forested. Of the 53 urban-site 

wells, 43 are completed in unconsolidated glacial 

sediments, and 10 are finished in bedrock; of the 20 

agricultural-site wells, 9 are completed in unconsolidated sediments, and 11 are completed in bedrock. Of 

the 27 forested-site wells, 11 are completed in unconsolidated deposits, and 16 are completed in bedrock 

(table 4).

The paucity of data on depth, locations, and hydrogeologic characteristics of wells for which nitrate data 

are available, and the temporal distribution of data 

collection, limit the usefulness of these data for a 

basinwide assessment. The wells for which information is available also are unevenly distributed with 

respect to depth (fig. 9A, p. 29). Whereas 62 of the 63 

samples from unconsolidated-aquifer sites are from 

wells completed at depths of 200 ft or less, only 21 of 

the 37 samples from bedrock aquifers are from depths 

less than 200 ft. Among the wells with depths 100 ft 

or less, 52 samples are from unconsolidated-aquifers, 

and only 10 are from bedrock. The temporal distribution of samples also is uneven; more than half of the 

63 samples from unconsolidated aquifers were 

collected in 1979 (fig. 9B), and more than two-thirds 

of the samples from bedrock aquifers were collected 

during 1987 and 1988 (fig. 9B).

Pesticides and Volatile Organic Compounds

Only 11 wells in the Hudson River basin are represented by analyses for pesticides and VOC's from 

1970 through 1990; six are in Fairfield County, 

Conn., one is in Schenectady County, N.Y., and four 

are in Sussex County, N.J. (fig. 8B and table 4).

Surface Water

NWIS data on nutrients, sediment, and pesticides 

are available from 56 sites in the Hudson River Basin 

(table 5). The following sections describe (1) the 

availability of nutrient and sediment data in terms of 

location, time, and flow regime, and (2) the availabil24 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
Table 4. Characteristics of wells in the Hudson River basin for which 1970-90 water-quality data are available

[Unc., unconsolidated; B, bedrock. U, urban; F, forest; A, agricultural. All sites have dissolved nitrate data; those 

with an asterisk also have pesticide and volatile organic compound data]

Depth,

Station- below land Year of

identification surface Sample Type of

number (feet) collection aquifer

CONNECTICUT - Fairfield County

411835073304001* 30 1984 Unc

411902073303601* 29.6 1984 Unc

411942073314201 18.4 1984 Unc

411947073314801* 32.7 1984 Unc

411951073315201 28.7 1984 Unc

411957073322301* 22.2 1984 Unc

411958073315901* 19.5 1984 Unc

412129073322201* 9.3 1989 Unc

MASSACHUSETTS - Berkshire County 

423134073112701 110 1970 B

423206073105901 182 1970 B

423359073084601 113 1969 Unc

423511073082901 103 1969 Unc

423554073143601 75 1969 B

423708073072601 85 1970 Unc

423737073164801 157 1969 B

423814073100801 200 1970 B

423840073064701 84 1969 Unc

423844073141001 240 1969 B

423955073063101 90 1969 Unc

424036073060501 110 1970 Unc

424149073091701 190 1969 Unc

424154073133301 65 1969 Unc

424224073115901 500 1969 B

424304073112301 150 1970 Unc

424309073113501 120 1969 Unc

424350073111701 300 1969 B

424403073043501 546 1970 B

424417073125201 80 1970 Unc

NEW JERSEY

Sussex County

410633074364601* 95 1988 B

411108074351901* 75 1988 B

411224074401201* 63 1988 B

411255074295101* 147 1988 B

Suffolk County

424125073495701 30 1979 Unc

NEW YORK - Albany County 

424125073495702 25 1979 Unc 

424125073495702 25 1979 Unc 

424139073514501 35 1979 Unc 

424139073514502 35 1979 Unc 

424155073545001 20 1979 Unc 

424215073505601 39 1979 Unc 

424222073541301 70 1979 Unc 

424231073514901 48 1979 Unc 

424232073514901 49 1979 Unc 

424232073515001 49 1979 Unc 

424232073515002 22 1979 Unc 

424241073535201 45 1979 Unc 

424244073535301 40 1979 Unc 

424247073515201 60 1979 Unc 

424247073515301 69 1979 Unc 

424247073515302 32 1979 Unc 

424249073521801 30.8 1979 Unc 

424250073521901 49 1979 Unc

Principal

land

use

Stationidentification

number

Depth,

below land Year of

surface Sample

(feet) collection

Type of

aquifer

Principal

land

use

NEW YORK - Albany County (cont.)

U

U

F

F

F

F

F

F

A

A

F

A

F

U

A

F

U

F

U

U

U

A

U

U

U

U

U

A

A

A

A

A

U

U 

U 

U 

U 

A 

U 

U 

U 

U 

U 

U 

U 

U 

F 

F 

F 

U 

U

424250073521902

424313073511201

424324073525501

424325073513001

424327073531101

424347073525701

424357073531201

424359073493901

424410073515301 

424422073493001

424448073535201

415818073393101

425558074330701

431229075241401

431233075242401

431243075243201

431244075241701

431246075244101

431252075243001

431258075243701

423534073423401

424910073591701*

424938073593101

424957073590001

425102074003601

425118074000801

415850074003501

410833073465901

411116073422301

411240073493801

411308073410001

25 1979

25 1979

25 1979

18 1979

30 1979

30 1979

30 1979

350 1979

30 1979 

20 1979

35 1979

Dutchess County

228 1975

Montgomery County

625 1973

Oneida County

21.5 1987

46 1987

35 1987

25 1987

41.5 1987

30.5 1987

25 1987

80.4 1982

Schenectady County

62 1973

60 1979

32 1979

75 1979

92 1979

Ulster County

79 1972

Westchester County

60 1971

500 1987

80 1988

300 1987

Unc

Unc

Unc

Unc

Unc

Unc

Unc

Unc

Unc 

Unc

Unc

B

B

Unc

Unc

Unc

Unc

Unc

Unc

Unc

Unc

Unc

Unc

Unc

Unc

Unc

Unc

B

B

B

B

411310073494901 160 1988 B 

411317073435601 50 1987 B 

411411073461901 125 1988 B 

411433073434901 200 1987 B 

411542073323601 350 1987 B 

411600073512201 300 1988 B 

411618073395401 325 1987 B 

411627073325701 180 1987 B 

411629073423901 125 1987 B 

411643073500101 90 1988 B 

411651073342101 240 1987 B 

411832073454201 205 1987 B 

411839073393301 400 1987 B 

411913073561801 180 1988 B 

411915073400701 425 1987 B 

411942073411201 80 1987 B 

411946073443001 900 1987 B 

412125073331801 750 1987 B 

VERMONT - Bennington County

424628073143401 58 1970 Unc

U

U

U

U

U

U

U

A

U 

A

A

A

A

U

U

U

U

U

U

U

U

U

U

U

U

A

F

U

F

F

F

F 

F 

F 

F 

F 

F 

U 

U 

F 

F 

A 

A 

U 

F 

U 

U 

U 

F

A

Water-Quality Assessment 25
76' 75' 74° 73"

44

43

42'

41'

VERMONT

"U^-')

S 

/ 

I

^IM^

( |Benningfon[

EXPLANATION

 County boundary

 .. Basin boundary

o Well finished in 

unconsolidated 

aquifer

 Well finished in 

bedrock aquifer

-" / ^ !

/MASSACHUSETTS 

(*' '^

\' Berkshire I

V

-* s Ulster i 

11

10 20 30 40 50 MILES

I I I I I

I I \ I I I

0 10 20 30 40 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 8A. Locations of wells in Hudson River basin in eastern New York and adjacent States for which 1970-90 

dissolved nitrate data were available.

26 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
76' 75' 74° 73°

EXPLANATION

 County boundary

 Basin boundary 

o Well location

10 20 30 40 50 MILES

I I I I I

/TX /vr^i pairfi

; e°?v>Cx7r\ x?'

x

Fairfield ^

I I I I I I

0 10 20 30 40 50 KILOMETERS

X\ df^i S v/ n

^;

NEW JERSEY

J

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 8B. Locations of wells in Hudson River basin in eastern New York and adjacent States for which 1970-90 pesticide and 

volatile organic compound data were available.

Water-Quality Assessment 27
Table 5. Name, location and drainage area, and types of data available from surface-water sites in the U.S. Geological 

Survey National Water Inventory System database from which nutrient, suspended sediment, or pesticide data are available. 

[Site locations are shown in fig. 10. N, nutrient data; S, suspended sediment data; P, pesticide data. M?, square miles]

Site 

no.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27A

27B

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

U.S. 

Geological 

Survey no.

01315500

01317000

01319000

01325005

01325420

01327600

01327750

01329640

01329650

01329907

01330770

01331095

01333300

01333360

01334805

01335770

01342602

01343902

01349520

01349527

01349858

01350180

01350355

01350500

01351500

01354000

01357000

01357500

01358000

01359915

01359918

01361750

01362198

01362342

01364501

01364959

01364974

01367620

01367700

01367770

01367910

01368950

01372003

01372005

01372044

01372500

01372547

01373500

01373860

01374300

01374398

01374963

01376500

Site Name

Hudson River at North Creek, NY

Schroon River at Riverbank, NY

East Branch Sacandaga River at Griffin, NY

Sacandaga River at Hadley, NY

Hudson River at Corinth, NY

Hudson River at Glens Falls, NY

Hudson River at Fort Edward, NY

Batten Kill at Middle Falls, NY

Hudson River at Schuylerville, NY

Clover Mill Brook on Shaw Hill Rd near Rock City Falls, NY

Kayaderosseras Creek at Saratoga Springs, NY

Hudson River at Stillwater, NY

Hoosic River below Williamstown, MA

Hoosic River at North Petersburg, NY

Hoosic River at Eagle Bridge, NY

Hudson River at Waterfbrd, NY

Mohawk River near Utica, NY

Utica Water Supply Intake on West Canada Creek, NY

Cayadutta Creek at Fonda, NY

Mohawk River above State Highway 30 at Fonda, NY

Silver Lake Outlet at Hensonville, NY

Schoharie Creek at North Blenheim, NY

Schoharie Creek at Breakabeen, NY

Schoharie Creek at Middleburg, NY

Schoharie Creek at Burtonsville, NY

Mohawk River at Tribes Hill, NY

Mohawk River at Crescent Dam, NY

Mohawk River at Cohoes, NY

Hudson River at Green Island, NY

Hannacrois Creek at Dormansville, NY

Silver Creek at Dormansville, NY

Basic Creek at South Westerlo, NY

Esopus Creek at Shandaken, NY

Hollow Tree Brook at Lanesville ,NY

Esopus Creek at Saugerties, NY

Rondout Creek above Red Brook at Peekamoose, NY

Rhinebeck Water Plant Intake on Hudson River, NY

Wallkill River at Outflow of Lake Mohawk at Sparta, NJ

Wallkill River at Franklin, NJ

Wallkill River near Sussex, NJ

Papakating Creek at Sussex, NJ

Black Creek near Vernon, NJ

Wallkill River near Rosendale, NY

Rondout Creek at Eddyville, NY

Twaalfskill near Highland, NY

Wappinger Creek near Wappingers Falls, NY

Chelsea Water Plant Intake on Hudson River, NY

Fishkill Creek at Beacon, NY

Moodna Creek near New Windsor, NY

Peekskill Hollow Creek at Van Cortlandtville, NY

Furnace Brook near Croton-on-Hudson, NY

Hallocks Mill Brook at Amawalk, NY

Saw Mill River atYonkers, NY

Latitude

43°42'03"

43°36'34"

43°28'25"

43°18'50"

43°14'55"

43°18'20"

43°16'10"

43°05'55"

43°05'54"

43°04'09"

43°02'37"

42°56'16"

42°44'28"

42°49'35"

42°57'05"

42°47'19"

43°05'26"

43°18'39"

42°57'13"

42°57'01"

42°17'43"

42°27'57"

42°32'13"

42°35'58"

42°48'00"

42°56'41"

42°48'21"

42°47'07"

42°45'08"

42°29'49"

42°29'17"

42°26'50"

42°06'59"

42°08'32"

42°04'16"

41°56'13"

41°55'38"

41°01'59"

41°06'43"

41°H'38"

41°12'02"

41°13'21"

41°48'53"

41°53'39"

41°41'42"

41°39'11"

41°33'49"

41°30'40"

41°27'32"

41°19'04"

41°13'51"

41°17'08"

40°56'11"

41 1218-073434700 Kisco River trib. Green Sreet at Mount Kisco, NY 41°12' 1 8"

41 1707-073500901 Mill Pond Trib off Hunter Brook Road at Yorktown ,NY

431230-075241001 Three Mile Creek at Rome, NY

435703-074051302 Winebrook Hills Plant Intake on Hudson River, NY

41°17'07"

43°12'30"

43°57'03"

Longitude

73°59'02"

73°44'17"

74°13'25"

73°50'45"

73°49'57"

73°36'58"

73°35'47"

73°31'32"

73°34'25"

73°56'20"

73°46'16"

73°39'04"

73°12'47"

73°19'21"

73°23'28"

73°40'28"

75°09'27"

75°06'38"

74°22'51"

74°22'21"

74°12'48"

74°27'45"

74°24'39"

74°20'12"

74°15'48"

74°17'19"

73°43'24"

73°42'29"

73°41'22"

73°58'46"

73°58'56"

74°01'37"

74°23'20"

74°15'55"

73°57'02"

74°22'30"

73°56'52"

74°38'36"

74°35'21"

74°34'32"

74°35'59"

74°28'33"

74°03'33"

74001'13"

73°59'08"

73°52'23"

73°57'30"

73°56'55"

74°01'27"

73°54'21"

73°54'24"

73°45'58"

73°53'12"

73°43'47"

73°50'09"

75°24'10"

74°05'13"

Drainage Types of 

Area data 

(mi2) available

792

527

114

1057

2755

2807

2817

434

3440

44.3

165

3770

204

233

571

4620

553

372

62.7

2120

6.66

358

444

534

886

3090

3440

3450

8090

13.5

2.90

18.3

59.5

1.95

425

5.36

10,510

4.38

29.4

60.8

59.4

17.3

764

1150

3.59

181

11,800

190

175

46.6

7.21

11.4

25.6

2.80

2.40

0.50

8.00

N

N

N

N

N

N,S

N,S

N

S

N

N

S

N,P

N,P

N

N,S,P

N

N

N

N

S

N

N

N

N

N

N

N,S,P

N,S,P

S

S

S

N,S,P

N

N

N

P

N,P

N,P

N,P

N,P

N,P

N

N

N,P

N

P

N

N

P

P

P

P

P

P

P

N,P

28 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
A.

 UNCONSOLIDATED AQUIFERS 63 samples

1 sample from 350-foot depth

19

8

J1771 V/L

7 -

vWvfyvMvfyY/hY/hrr7$/%777\ o o YTT\ o ° ° TTA -

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200

BEDROCK AQUIFERS 37 samples -

: 7 6 :

v//

' 3 kyy

r/xi \//j

V/AY//

V7A WA 33 ~

[rsJ\ \ffA fy/A \f/A 11111 1

VA VA VA VA V/A rrn rm WA rm " m 0 TTT\ 0 0 ,77, 0 -

0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1,000 

DEPTH, IN FEET BELOW UNO SURFACE

SAMPLE DISTRIBUTION, BY WELL DEPTH

UNCONSOLIDATED AQUIFERS

12

yft o r7!T1 Jly, ooooo

1970 71 72 73 74 75 76 77 78

_ BEDROCK AQUIFERS

L 9

: YsAr^n 0 .^V, 0 t}fl 000

33 

Y/

'/>

\

79

0

-i

77 ~ 

0 0 nJy, 0 [>^j 0 0 |^| 0 ,}fl 0 :

1980 81 82 83 84 85 86 87 88 89 1990

15 :

y/ 10 ' 

0000000^(^00

1970 71 72 73 74 75 76 77 78 79 1980 81 82 83 84 85 86 87 88 89 1990

YEAR

B. SAMPLE DISTRIBUTION, BY YEAR OF SAMPLE COLLECTION

Figure 9. Time and well-depth distribution of dissolved-nitrate analyses for unconsolidated and 

bedrock aquifers in the Hudson River basin in eastern New York and adjacent States, 1970-90: 

A. Sample distribution, by well depth. B. Sample distribution, by year of collection.

Nutrients

Data on dissolved nitrate, total nitrogen, dissolved 

ammonium, and total phosphorus in surface water 

were available from 42 sites (fig. 10 and table 6). All 

of these sites have data on dissolved nitrate, but not 

all have data on total phosphorus, total nitrogen, or 

dissolved ammonium. Of the 42 sites for which 

nutrient data are available, 21 also have daily 

discharge data (fig. 10). Only four sites with nutrient 

data are classified as urban, and only two of these 

(sites 13 and 14) have daily discharge records (table 

6); both are on the upper parts of the Hoosic River

downstream of Williamstown, within 10 mi of one 

another (fig. 10 and table 6). Of the remaining 19 

sites with nutrient and daily-discharge data, seven 

are agricultural, six are forested, and six are mixed. 

Most of the agricultural sites with available nutrient 

and daily discharge data are in the Mohawk River

/^

basin and have drainage areas greater than 900 mi z 

(sites 20, 25, 26, 27A , 27B in fig. 10 and table 6). 

Only one agricultural site for which nutrient and 

daily discharge data are available (Wappinger 

Creek, site 45) has a drainage area of less than 

200 mi2 .

Availability of Data, 1970-90 29
76' 75 c 74° 73°

44°

43'

42°

41'

Adirondack 

Mountains

a * f\ C** r ^ Jy s v^^

EXPLANATION

 Basin boundary

O'>48

,23

Site with nutrient data 

only

Site with nutrient and 

daily discharge record

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 10. Surface-water sites in Hudson River basin in eastern New York and adjacent States for which nutrient data, 

or nutrient and daily-discharge data, are available. (Site names are given in table 5).

30 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
Table 6. Land use and population density of watersheds represented by the 42 surfacewater sites in Hudson River basin from which 1970-90 nutrient data were available.

[Site locations are shown in fig. 10; site names are shown in table 5; * denotes daily 

discharge data available].

Site 

no.

1

2

3*

4*

5*

6*

7*

8

10

11

13*

14*

15

16*

17

18

19

20*

22*

23*

24*

25*

26*

27a*

27b*

28*

32*

33

34

35

37

38

39

40

41

42*

43*

44

45*

47

48

56

Land Use in Watershed area 

(in percent)

Site Category

Forest 

Forest

Forest

Forest

Forest

Forest

Forest

Agricultural

Forest

Agricultural

Urban

Urban

Mixed

Mixed

Agricultural

Forest

Mixed

Agricultural

Mixed

Mixed

Mixed

Agricultural

Agricultural

Agricultural

Agricultural

Mixed

Forest

Forest

Forest

Forest

Urban

Urban

Mixed

Agricultural

Mixed

Agricultural

Mixed

Agricultural

Agricultural

Mixed

Mixed

Forest

Urban

0.41 

1.60

0.00

1.32

1.12

1.34

1.36

1.23

0.900

6.55

10.7

9.89

7.50

3.34

11.2

0.321

11.7

4.65

2.49

1.99

1.93

2.17

3.89

6.09

6.12

4.65

1.65

0.00

6.35

0.00

44.7

21.1

13.4

3.63

22.5

8.97

7.25

2.94

4.58

10.8

15.2

0.00

Agricultural

0.28 

0.36

0.00

1.46

1.03

1.08

1.12

35.7

9.5

26.1

13.3

15.5

24.4

15.0

44.1

1.58

36.0

34.7

18.1

18.3

19.6

30.1

34.0

33.8

33.8

23.2

0.33

0.00

7.50

0.00

0.00

12.6

30.6

71.5

29.5

55.1

40.8

32.3

35.6

29.5

40.1

0.00

Forest

92.7 

93.6

94.3

87.4

91.1

90.9

90.8

62.3

89.6

66.3

74.8

73.7

67.5

76.7

40.1

88.9

48.1

54.9

75.3

76.2

75.4

64.8

57.2

55.0

55.0

67.1

94.4

100.00

82.6

100.00

29.8

57.9

50.5

24.3

42.2

35.6

51.3

67.7

58.1

58.7

42.5

94.5

Watershed population 

(per square mile)

1980

3.28 

12.0

0.00

29.9

18.9

26.6

27.0

34.4

101

196

211

195

134

69.1

368

3.24

345

150

22.1

22.3

28.6

40.8

118

174

175

118

7.76

0.00

152

0.00

1140

417

397

156

342

247

189

245

174

253

283

0.00

1990

4.78 

9.39

14.1

18.7

15.8

23.7

24.3

41.8

78.2

218

198

183

135

70.9

358

5.06

512

150

26.3

24.9

28.5

46.3

117

175

176

119

13.9

0.00

154

0.00

1710

442

450

215

350

290

219

245

129

294

364

0.00

Availability of Data, 1970-90 31
Six sites (sites 13, 27 A, 27B, 28, 32 and 45 in 

fig. 10) with daily-discharge data were chosen for an 

analysis of the number of samples available, the years 

represented, and the distribution of samples over the 

range of flow conditions for four nutrients during 

1970-90; the patterns of nutrient-data availability at 

these sites is typical of sites across the Hudson River 

basin. The constituents most frequently sampled for 

are dissolved nitrate and total phosphorus (table 7). 

Dissolved nitrate is the most commonly sampled 

nutrient and, therefore, is used in this report to represent the availability of all nutrient data.

Most samples for dissolved-nitrate analysis were 

collected during 1970-80 at the six sites; only a few 

samples were collected during 1981-90 (table 8). Only 

two of the sites-Esopus Creek at Shandaken (site 32) 

and Hudson River at Green Island (site 28)-have 

nutrient data for each year of 1970-90, and even at 

these locations, the sampling frequency declined 

substantially during the 1980's (table 8). Samples 

were collected at the outlet of the Mohawk River at 

Crescent Dam (site 27A in fig. 10) for dissolved 

nitrate analysis during 1970-78; after 1978, the 

sampling location was shifted 2 mi downstream to 

Cohoes (site 27B), where most of the samples for 

dissolved nitrate analysis were collected after 1988 

(table 8). The analysis of nutrient concentrations at the 

Mohawk River outlet in this report is based mostly on 

data collected from Crescent Dam (site 27A) because 

few data are available from the Cohoes site.The inconsistency of nutrient-data collection by year restricts

Table 7. Number of samples collected at selected sites in 

Hudson River basin for nutrient analysis, 1970-90 .

[Site locations are shown in fig. 10; names are given in table 5]

Table 8. Number of samples collected for dissolved nitrate 

analyses from selected sites with discharge data in the 

Hudson River basin, 1970-90, by year.

[Site locations are shown in fig. 10, names are given in table 7. 

Dash indicates no data available]

Nutrient

Site 

no.

13

27A

27B

28

32

45

Site Name

Hoosic River below 

Williamstown MA

Mohawk River at 

Crescent Dam ,NY

Mohawk River at 

Cohoes, NY

Hudson River at 

Green Island, NY

Esopus Creek at 

Shandaken, NY

Wappinger Creek 

near Wappingers 

Falls, NY

Total 

nitrogen

10

109

32

131

48

37

Dissolved 

nitrate

49

170

34

162

181

72

Dissolved 

ammonium

8

98

1

102

70

50

Total 

phosphorus

49

169

20

159

170

67

Number of Samples

Year

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

Site 1 3 Site 27a

12 25

12 26

12 25

12 22

1 25

18

10

8

11

-

-

-

-

-

-

-

-

-

-

-

-

Site 27b Site 28

1 12

12

12

13

12

10

10

8

9

13 9

12

12

6

4

4

4

3

1

2 4

11 3

7 2

Site 32

10

11

12

11

12

11

12

12

12

11

12

12

12

7

4

4

5

2

4

3

2

Site 45

12

14

13

13

12

8

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

the usefulness of the data for a basinwide assessment 

of current conditions and trends, and the lack of data 

after 1980 largely restricts the basinwide assessment 

of nutrient concentrations to 1970-80. The only available temporal-trend analyses of nutrients are those 

reported for dissolved nitrate at two forested sites in 

the Catskill Mountains by Murdoch and Stoddard 

(1992) from NYCDEP data. Wappinger Creek is a site 

with a monthly sampling pattern that is representative 

of most sites with more than 40 samples and shows an 

even distribution throughout the year (fig. 11 A). 

Mohawk River at Crescent Dam is another representative site; the frequency of sample collection per month 

at this site is less consistent than at Wappinger Creek, 

however, because few samples were collected in the 

winter months, possibly because of ice conditions.

All sites with both nutrient and daily discharge data 

had at least one sample representing high flow conditions (discharge that is exceeded 10 percent of the 

time); therefore, nutrient data representing high-flow 

conditions are generally available-more than 20

32 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
10

A. WAPPINGER CREEK NEAR

. WAPPINGER FALLS

-

-

i

ys

/

N\\\\\\\\X\\\\V

ys

/

NXXXXXXXXXXXXXX

/

s

>X\\\\\\\\\\\\N !

-

/

/

XXXXXXXXXXXXXXN

/

s

y

rr^

XXXXXXXXXXXXXXN

r»~i

XXXXXXXXXXXXXXN

__ _

-

ONDJ FMAMJ JAS

20

16

12

-

.

-

~

-

\S

f

S

s

/

y

NXXXXXXXXXXXXXXX

7-

s

/

NXXXXXXXXXXXXXXX

NXXXXXXXXXN

f

S

/

/

y

NXXXXXXXXXXXXXXX

IS

NXXXXXXXXXXXXXXX

1y

'i

y

y

NXXXXXXXXXXXXXXX

B. MOHAWK RIVER AT "

CRESCENT DAM ]

Is

s

y

NXXXXXXXXXXXXXXX NXXXXXXXXXXXXXXX

7-

S

/

NXXXXXXXXXXXXXXX

I

NXXXXXXXXXXXXXXX

1

NXXXXXXXXXXXXXXX

_

-

V.

NXXXXXXXXXXXXXXX

-

-

ONDJ FMAMJ JAS 

MONTH

Figure 11. Number of water samples collected monthly at 

two sites in the Hudson River basin during 1970-90 for 

dissolved nitrate analysis,. (Locations are shown in fig. 10).

samples for dissolved nitrate analyses were collected at 

the Mohawk River at Crescent Dam during high-flow 

conditions (table 9). More than 10 samples were 

collected during low-flow conditions (discharges that 

were exceeded 80 percent of the time). The distribution 

of dissolved nitrate samples over the flow range at 

Wappinger Creek near Wappingers Falls is similar; 14 

samples represent high-flow conditions, whereas only 

9 represent low-flow conditions. In contrast, fewer 

samples were collected during high-flow conditions 

than during low-flow conditions at the Hoosic River 

below Williamstown and at Esopus Creek at 

Shandaken (table 9), although more than 5 samples 

represent high-flow conditions at these sites. The large 

percentage of samples representing high-flow condiTable 9. Number of samples collected for dissolved nitrate 

analyses during high and low flows at select sites in the 

Hudson River basin, 1970-90.

[Locations are shown in fig. 10; names in table 5. High flow 

includes discharges exceeded 10 percent of the time or less; low 

flow includes discharges exceeded 80 percent of the time or more.

Site 

no.

13

27A

27B

28

32

45

Number of samples 

collected

Site name

Hoosic River below Williamstown, Mass.

Mohawk River at Crescent Dam

Mohawk River at Cohoes N.Y.

Hudson River at Green Island, .

Esopus Creek at Shandaken, NY.

Wappinger Creek near 

Wappingers Falls NY.

High flow

6

22

7

21

21

14

Low flow

13

15

4

21

33

9

tions is likely attributable to high-flow conditions 

during 1970-80. Yet, the dissolved nitrate analyses 

represent a sufficiently wide range of flow conditions 

that the relations between discharge and nutrient 

concentration could be assessed. These results indicate 

that the distribution of data collected at sites with (1) 

daily discharge records and (2) analyses of more than 

40 samples for nutrients, is generally adequate for 

plotting nitrate concentration as a function of discharge 

and for calculating nutrient yields.

Suspended Sediment

All suspended-sediment data used in the analysis 

herein are from the NWIS database. Eight of the 12 

sites with suspended-sediment data have more than 

40 samples and, thus, were considered suitable for 

analysis (fig. 12 and table 10), and all eight of these 

sites have more than 90 samples from 1970-90. Five 

of these sites are on the main stem of the upper 

Hudson River (sites 6, 7, 9, 12, 16; see fig. 12 and 

table 10) and were sampled by the USGS in cooperation with the NYSDEC as part of a long-term PCBmonitoring program; two of these sites have daily 

suspended-sediment data-site 12 (Hudson River at 

Still water) and site 16 (Hudson River at Waterford). 

Suspended-sediment samples also were collected 

from the Hudson River at Green Island (site 28) as 

part of the USGS NASQAN (National StreamQuality Accounting Network) program, and at the 

Esopus Creek at Shandaken (site 32) as part of the 

USGS Hydrologic Benchmark program (Firda and

Availability of Data, 1970-90 33
76' 75 c 74 c 73°

44

43'

42 c

41 C

Adirondack 

Mountains VERMONT

EXPLANATION 

 -^ Basin boundary

^28

Site with daily

suspended-sediment

data

o

32 Site with suspendedsediment data

0 10 20 30 40 50 MILES

I I I I I I

I I I I I I

0 10 20 30 40 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 12. Locations of surface-water sites in Hudson River basin in eastern New York from which suspended-sediment 

data were available, 1970-90. (Site names are given in table 10).

34 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
Table 10. Data on numbers of samples collected at eight sites in the Hudson River basin, N.Y., that have 

discharge records and more than 40 suspended-sediment samples, 1970-90.

[ Flow duration is percentage of time discharge was exceeded. Dashes indicate no data available. Site locations 

are shown in fig. 12]

A. Site number and name, land-use category, and high-flow data.

Suspended-sediment samples

Site 

no. Site Name

No. collected at high 

flow (discharge 

Predominant land Total exceeded 10 percent 

use in watershed collected of time or less)

6 Hudson River at Glens Falls Forest 90 

7 Hudson River at Fort Edward Forest 423 

9 Hudson River at Schuylerville Forest 293 

12* Hudson River at Stillwater Forest 3,297 

16* Hudson River at Waterford Mixed 4,007 

27B Mohawk River at Cohoes Agriculture 156 

28 Hudson River at Green Island Mixed 96 

32 Esopus Creek at Shandaken Forest 168

23 

132

415 

476 

**70 

13 

17

Flow duration for 

sample representing 

highest discharge

0.05 

0.03

0.04 

0.04 

0.01 

0.60 

0.06

*Site with daily suspended-sediment values. 

**Some samples were collected on same day

B. Number of suspended-sediment samples collected in 1970-90 by year and season

Number ofsamples

Year

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

Site6

-

-

-

-

-

2

-

25

50

13

-

-

-

-

-

-

-

-

-

-

-

Site?

-

-

-

-

-

6

4

-

28

49

63

53

66

37

2

16

7

28

31

33

-

Site 9

-

-

-

-

-

-

2

55

16

12

13

25

35

38

1

17

5

17

20

28

9

Site 12

-

-

-

-

-

-

-

199

365

346

335

282

213

283

206

117

217

106

246

112

270

Site 16

-

-

-

-

-

-

-

365

365

365

366

308

308

334

274

108

249

115

296

317

237

Site27B

-

-

-

-

-

-

20

95

2

23

-

-

-

-

-

-

-

-

2

9

5

Site 28

-

-

-

-

-

4

11

7

9

10

12

12

6

4

4

4

4

-

4

3

2

Site 32

8

8

12

12

8

13

14

14

12

9

12

11

10

4

4

5

3

-

3

3

2

Season

Winter (Jan-Mar)

Spring (Apr-June)

Summer (July-Sep)

Fall (Oct-Dec)

4

31

23

32

69

152

143

59

46

115

93

39

548

984

941

824

758

1096

1096

1057

42

22

25

67

16

26

29

25

40

42

46

39

Availability of Data, 1970-90 35
others, 1993). All eight of these sites except Hudson 

River at Schuylerville (site 9) have daily discharge 

records that enable calculation of sediment-transport 

rates. In general, these sites represent forested or 

mixed land-use watersheds; only one (site 27B, 

Mohawk River at Cohoes) is agricultural. No 

suspended-sediment data are available for urban 

watersheds.

The distribution of suspended-sediment data 

collection, by year, differs considerably among the 

sites. The sites with daily sediment records-Hudson 

River at Stillwater (site 12) and Hudson River at 

Waterford (site 16, fig. 12)-have average daily 

sediment-concentration and yield data for more than 

250 days in each of most years during 1977-90 (table 

10B). Most suspended-sediment samples were 

collected at the Hudson River at Fort Edward (site 7) 

and the Hudson River at Schuylerville (site 9) were 

collected during 1978-83. In contrast, all samples 

from the Hudson River at Glens Falls (site 6) were 

collected during 1975-79. More than half of the 

suspended-sediment samples from the Mohawk 

River at Cohoes were collected in 1977 (table 10B), 

and suspended-sediment data were not collected in 

most years. Although adequate numbers of 

suspended-sediment samples were collected at 

Esopus Creek at Shandaken (site 32) and the Hudson 

River at Green Island (site 28) (table 10B), the 

sampling frequency at these sites decreased by more 

than half after 1982.

The seasonal distribution of suspended-sediment 

data collection is uneven for some sites (table 10B). 

At most sites without daily sediment data, fewer than 

15 percent of the suspended-sediment samples were 

collected in the winter (December, January and 

February), largely because ice cover makes sample 

collection difficult. For example, the number of 

winter samples collected at Fort Edward (site 7) is 

one-half to one-third of the number collected in other 

seasons (table 10B), and fewer samples were 

collected at Stillwater and Waterford (sites 12 and 

16) in winter than in other seasons.

Suspended-sediment data are available over a 

wide range of flow conditions, including high flow 

conditions at all seven sites with daily discharge 

records (table 10B). These seven sites have 10 or 

more analyses for days of high flow, when the daily 

mean discharge was exceeded 10 percent of the time 

or less, and nearly all have analyses for discharges 

that are exceeded less than 0.1 percent of the time.

The distribution of suspended-sediment data by 

watershed and land-use category is inadequate for a 

basinwide assessment of suspended sediment. Even 

though sediment data for the mainstem of the upper 

Hudson River are plentiful, no data for tributaries to 

the upper Hudson or Mohawk Rivers are available; 

thus, neither the major sources of sediment to the 

Hudson and Mohawk Rivers, nor the relations 

between land use and suspended-sediment concentrations, can be identified. Assessment of current 

suspended-sediment conditions at the Mohawk River 

at Crescent Dam is also impossible because few 

samples for suspended-sediment analyses were 

collected there after 1977.

Pesticides

The pesticide data analyzed herein are largely from 

the NWIS database and are based on only a few 

samples. Only five pesticides in streambed samples 

have data from 10 or more sites in at least two watersheds-these are DDD (dichlorodiphenyldichloroethane), DDE (dichlorodiphenyldichloroethane), 

DDT, chlordane, and aldrin; only one compound 

dissolved in the water column (2,4-D) has data from 

10 or more sites. All of these compounds except 2,4- 

D are persistent insecticides (Ware, 1989); 2,4-D is 

less persistent and more water soluble than the others. 

Locations of sites with pesticide data are shown in 

figure 13. In this report, the bed-sediment concentrations of DDT, DDE, and DDD are combined and 

reported as total DDT (fig. 14). Chlordane and aldrin 

data are available from 22 sites, total DDT from 21 

sites, and 2,4-D from only 11 sites (table 11). Nearly 

half the sites with data for the first five pesticides 

represent urban watersheds; the remainder represent 

forested, agricultural, and mixed-use watersheds (fig. 

14). The 2,4-D data are evenly distributed among the 

different types of sites (fig. 14).

All pesticide samples were collected during 1972- 

77 (table 11) except those from the upper Wallkill 

River basin, where chlordane, aldrin, and total DDT 

sampling (sites 37-41) was generally more recent 

(through 1990). No samples for 2,4-D analysis were 

collected after 1982.

In general, pesticide data are inadequate for a 

basinwide assessment of pesticide distribution in 

streambed sediment in the Hudson River basin. Few 

data on persistent pesticide compounds (such as 

chlordane and total DDT) are available for areas

36 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
76' 75' 74° 73°

Adirondack 

Mountains VERMONT

EXPLANATION

 - - Basin boundary

36 Site with pesticide 

data

0 10 20 30 40 50 MILES

I I I I I I

I I I I I I

0 10 20 30 40 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45 ° 30', central meridian -74°

Figure 13. Locations of surface-water sites in the Hudson River basin in eastern New York and adjacent States from which pesticide data are available. (Site names are given in table 5)

Availability of Data, 1970-90 37
outside northern New Jersey after 1980 (table 11), 

and no water-column-concentration data on many 

widely used pesticides, including atrazine, alachlor, 

cyanazine, carbofuran, and carbaryl, are available. In 

addition, 2,4-D data are limited to one sample per site; 

thus, no information is available on 2,4-D concentrations under differing flow conditions or during different seasons. The lack of water-column data on pesticides and streambed sediment limit the analyses to (1) 

broad comparisons of detection rates, and (2) comparisons of median concentrations of a few persistent 

pesticides at sites in urban watersheds with those at 

nonurban watersheds.

Table 11. Years of pesticide-data collection in the Hudson 

River basin, 1970-90, by site.

[ Locations are shown in fig. 13, names in table 5. Dashes indicate 

no data available.]

Pesticide

Site 

no.

\3

14

\6

IS

21

27A

28

29

30

31

32

36

37

38

39

40

41

44

46

49

50

51

52

53

54

55

56

Land-use 

Category

Urban

Urban

Mixed

Forest

Forest

Agricultural

Mixed

Mixed

Agricultural

Agricultural

Mixed

Estuary

Urban

Urban

Mixed

Urban

Mixed

Agricultural

Estuary

Urban

Urban

Urban

Urban

Urban

Urban

Urban

Forest

Aldrin

-

1972

-

-

1975

1974

-

1978

1978

1978

1970-82

-

1980

1982-89

1978-89

1978-90

1978-90

1974

1974

1976

1976

1976

1976-77

1976-77

1976

1987

1974

Chlordane

-

1972

-

-

1975

1974

-

1978

1978

1978

1970-82

-

1980

1982-89

1978-89

1978-90

1978-90

1974

1974

1976

1976

1976

1976-77

1977

1976

1987

1974

ODD, 

DOT, 

DDE

-

1972

-

-

1975

1974

-

1978

1978

1978

1970-82

-

1980

1982-89

1978-89

1978-90

1978-90

1974

1974

1976

1976

1976

1976-77

1976-77

1976

-

1974

2,4-D

1972-73

1970-72

1973-74

1974

-

1973-77

1982

-

-

-

1970-82

1971-73

-

-

-

-

-

1974

1970

-

-

-

-

-

-

-

1974

20 

15

10 

5 

0 

TOTAL DOT

10

-

3

%

x> 06

v\2r *y <P .£ J

ff. //

21 -

7771

i

-

-

ifv o^ c\ v<y ^ ^V* ^°

25

20

15

m 10

2,4-D

" 3

: fa %

222

11 -

II

^ :

Land-Use Category

Figure 14. Number of sites in Hudson River basin, N.Y., 

with concentration data for total DOT or 2,4-D, by landuse category, 1970-90.

38 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
ANALYSIS OF NUTRIENT, PESTICIDE, 

VOLATILE ORGANIC COMPOUND, AND 

SUSPENDED-SEDIMENT DATA

The following analysis provides a preliminary 

basinwide ground-water and surface-water assessment. The ground-water section addresses nitrate, 

selected pesticides, and several VOC's; the surfacewater section addresses nutrients, suspendedsediment, and pesticides. Both sections discuss (1) 

relations among nutrient concentrations, hydrologic 

conditions, and land use; and (2) pesticide concentrations and their relation to land use. The surfacewater section also summarizes suspended-sediment 

concentrations at selected sites and gives computed 

yields of nutrients in surface water and suspended 

sediment.

Ground Water

The nutrient data discussed in this section are 

limited to nitrate because data on other nutrient 

species were sparse or lacking. Nitrate concentrations 

in ground water are compared with natural factors, 

such as type of aquifer material and well depth, as 

well as human factors, such as land use. Pesticide and 

VOC concentrations, by contrast, are compared only 

with human-derived factors.

Nitrate

Nitrate is the most soluble and mobile form of 

nitrogen in ground water. Previous investigations have 

indicated that all principal aquifers in New York State, 

both unconsolidated and bedrock, contain ground 

water with median nitrate concentrations as N (nitrogen) less than the 10-mg/L USEPA drinking-water 

standard (Rogers, 1988). (All references to concentrations of nitrogen in this report are expressed as N.) 

Elevated concentrations may be found, however, in 

shallow, unconfined systems that are susceptible to 

contamination from overlying sources of nitrate, such 

as fertilizers, underground sewage-disposal systems, 

animal waste, and landfills (Rogers, 1988).

Results of a study by Madison and Brunett (1984) 

indicate that background concentrations of nitrate are 

low (less than 0.2 mg/L) and that a threshold nitrate 

concentration indicative of human effects is 0.2 to 

0.3 mg/L. A threshold concentration of 0.3 mg/L was 

estimated for this study from a probability distribution (SAS Institute, Inc., 1990) of the available nitrate

data (fig. 15). The threshold was obtained through a 

qualitative determination that 0.3 mg/L corresponded 

to the steepest part of the dissolved nitrate probability 

plot and is interpreted as representing a point separating two populations of data.

100

O

Icc cc

UJ Zi

O

Q ^

O 

CO 

CO 

Q

0.1

0.01

r Threshhold = 0.3 mg/L

-3 -2

NORMAL QUANTILES

Figure 15. Dissolved nitrate concentrations in water from 

wells completed in bedrock and unconsolidated aquifers in 

the Hudson River basin in eastern New York and adjacent 

States, as a function of normal distribution, 1970-90.

Boxplots summarizing the concentrations of 

dissolved nitrate in ground-water samples from wells 

throughout the study area are given in figure 16A. Of 

the 100 ground-water samples represented in this 

report, 63 are from wells completed in unconsolidated 

glacial material, and 37 are from wells completed in 

bedrock. Two samples exceed the Federal and State 

maximum contaminant level of 10 mg/L-one is from 

an unconsolidated aquifer, and one from a bedrock 

aquifer. Nitrate concentrations in water from unconsolidated deposits range from less than the analytical 

detection limit of 0.1 mg/L to 16 mg/L, with a median 

concentration of 0.23 mg/L, and nitrate concentrations 

in water from bedrock range from less than 0.1 to 

11 mg/L, with a median concentration of 0.3 mg/L. 

Depths of wells completed in unconsolidated deposits 

range from 9.35 to 350 ft below land surface, with a 

median of 35 ft, and depths of wells completed in 

bedrock aquifers range from 50 to 900 ft below land 

surface, with a median of 200 ft.

The effects of local differences in geology or other 

factors on nitrate concentration in ground water were 

evaluated through a comparison between two areas: 

one representing unconsolidated material (Albany 

and Schenectady Counties, 42 wells), the other

Analysis Of Nutrient, Pesticide, Volatile Organic Compound, And Suspended-sediment Data 39
o

hDC DC

100

10

y s 1 < <

0.1

0.01

63

Maximum contaminant 

level

37

Detection limit

All unconsolidated 

aquifers

All bedrock 

aquifers

A. ALL AQUIFERS

100

0

0.01

42

Maximum contaminant 

level

21

Detection limit

Albany/Schenectady Counties Westchester County 

(unconsolidated aquifer) (bedrock aquifer)

B. TWO REPRESENTATIVE AQUIFERS

EXPLANATION

Number of

samples 37

90 Percentile

75

50

25

10

mg/l = milligrams per liter

Figure 16. Range of dissolved nitrate concentrations in 

relation to aquifer type in the Hudson River basin in 

eastern New York and adjacent States, 1970-90: A. All 

aquifers, by aquifer type. B. Two representative unconsolidated aquifers in Albany and Schenectady Counties and 

bedrock aquifers in Westchester County.

representing bedrock (Westchester County, 21 wells). 

Nitrate concentrations in the unconsolidated-aquifer 

locality range from less than the reporting limit of 

0.1 to 16 mg/L with a median of 0.48 mg/L, whereas 

those in the bedrock-aquifer locality range from less 

than 0.1 to 6.3 mg/L with a median of 0.43 mg/L. 

Boxplots summarizing nitrate concentrations in 

ground-water samples collected in these areas are 

given in figure 16B.

The Wilcoxon rank sum test (SAS Institute, Inc., 

1990) (a nonparametric statistical test) was used to 

determine whether nitrate concentrations in unconsolidated aquifers differ from those in bedrock 

aquifers. The alpha value, or level of significance, 

used in this test was 0.05. In this test, the null hypothesis was accepted with a probability value of 0.81, 

indicating no statistically significant difference 

between nitrate concentrations in unconsolidated 

aquifers of Albany and Schenectady Counties and 

those in bedrock aquifers of Westchester County.

In general, nitrate concentrations in ground water 

decreased with depth. The relation between nitrate 

concentration and well depth for wells screened in 

unconsolidated aquifers in the Hudson River basin 

(fig. 17A) indicates the expected decrease, but the 

plot for bedrock aquifers suggests some other control 

on nitrate concentrations (fig. 17A). The graph of 

nitrate concentrations in relation to depth in bedrock 

aquifers suggests two populations of data-those 

affected, and those unaffected; the controlling factor 

appears to be land use. Statistical tests were done on 

depth and land use to test whether these apparent 

controls are real or the result of chance differences.

Box plots of nitrate concentrations by well depth 

(fig. 17B) indicate a median nitrate concentration of 

0.61 mg/L for unconsolidated aquifers in wells less 

than 35 ft deep, and 0.2 mg/L in wells more than 35 ft 

deep, confirming that nitrate concentrations decrease 

with depth. In bedrock aquifers, however, concentrations at depths less than 200 ft range from less than 

0.1 to 11 mg/L with a median of 0.26 mg/L, and 

those at depths greater than 200 ft range from less 

than 0.1 to 3.6 mg/L, with a median of 0.43 mg/L. 

Ground water in bedrock aquifers flows along zones 

of secondary permeability, such as fractures and 

bedding-plane openings; thus, the high concentrations of nitrate at depth are probably the result of 

downward flow along fractures that could extend 

from land surface and provide a direct conduit for 

shallow ground-water flow into deep zones.

40 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
100

10

0.1

0.01

UNCONSOLIDATED AQUIFERS

LOWESS 

smooth line

L V.'

100

10

0.1

0.01

0 50 100 150 200

WELL DEPTH, IN FEET BELOW LAND SURFACE 

CONCENTRATION AS A FUNCTION OF DEPTH

BEDROCK AQUIFERS

0 50 100 150 200 250 300 350 

WELL DEPTH, IN FEET BELOW LAND SURFACE

Z 100

o

11 10

}^i 1

H CD

zd

^^ 0.1

O ~

5 0.01

: UNCONSOLIDATED AQUIFERS :

32 :

[ J J

:

|

30 I

I ]

Detection limit -

EXPLANATION

Number of

samples 37

Less than or Greater than 

equal to 35 feet 35 feet

90 Pencentile

75

50

25

10

100

10

: BEDROCK AQUIFERS 

20

0.1

0.01

17

\ Detection limit

WELL DEPTH 

B. CONCENTRATION RANGE IN SHALLOW AND DEEP WELLS

Less than or Greater than 

equal to 200 feet 200 feet

WELL DEPTH

Figure 17. Dissolved nitrate concentrations in relation to well depth in unconsolidated and bedrock aquifers in the 

Hudson River basin in eastern New York and adjacent States, 1970-90. A. Concentration as a function of well depth. 

B. Concentration range in shallow and deep wells

The Wilcoxon rank sum test (SAS Institute, Inc., 

1990) was used to indicate whether changes in 

nitrate concentration with depth in both types of 

aquifers result from chance variability or represent 

real differences. The alpha value used in this test 

was 0.05. In unconsolidated aquifers, the null 

hypothesis was rejected with a probability value 

of 0.04, indicating a statistically significant difference in the nitrate concentrations in samples from 

wells 35 ft deep or less, and in samples from wells 

more than 35 ft deep. In bedrock aquifers, a probability value of 0.74 indicates no statistically 

significant difference between samples from wells

200 ft deep or less and those from wells more than 

200 feet deep.

Nitrate data for the unconsolidated and bedrock 

aquifers also were analyzed in relation to three 

categories of land use type; results are presented in 

boxplots in figure 18. Median concentrations for the 

three land use categories among unconsolidated 

aquifers range from less than 0.1 to 0.6 mg/L; the 

highest median concentration represents forest 

settings (fig. ISA). Median concentrations, by land 

use, in bedrock aquifers range from 0.2 to 2.81 mg/L; 

the highest median concentration (2.81 mg/L) represents an agricultural area (fig. 18B).

Analysis Of Nutrient, Pesticide, Volatile Organic Compound, And Suspended-sediment Data 41
100

10

O 

oc oc

§^

CD

> z °' 1

O ~ 

CO 

CO 

Q

0.01

A. UNCONSOLIDATED AQUIFERS

11

43

^ Detection limit

Urban Agricultural Forest

O

cc oc

I- HI Z ho

111

100

..«10

oc

O 

CO 

CO

Q

CD

0.1

0.01

B. BEDROCK AQUIFERS 

11

^ Detection limit

Urban Agricultural Forest 

LAND-USE CATEGORY

EXPLANATION

Number of 

samples 37

90 Percentile

75

50

25

10

Figure 18. Range of dissolved nitrate concentrations in 

water from wells in the Hudson River basin in eastern New 

York and adjacent States, 1970-90, by land use and aquifer 

type: A. Unconsolidated aquifers. B. Bedrock aquifers.

The Kruskal-Wallis test (SAS Institute, Inc., 1990) 

is a nonparametric test used to determine whether all 

groups have (1) the same median, or (2) at least one 

median that differs from the rest. The null hypothesis 

of this test is that all groups of data have identical 

distributions. The alpha value used in this test is 0.05. 

A probability value smaller than or equal to the alpha 

value indicates that the groups differ significantly. 

Neither the samples from unconsolidated aquifers 

(probability value = 0.15), nor those from bedrock 

aquifers (probability value = 0.10) showed significant 

differences with respect to land-use category; therefore, no correlation between nitrate concentration and 

land use in the Hudson River basin can be made from 

available ground-water-quality data.

Two of the land-use categories were then 

combined in an effort to indicate the effect of land 

use on nitrate concentrations in bedrock aquifers. 

The agricultural and urban categories were 

combined as "developed" land and compared with 

forest or "undeveloped" land, and the data were 

reapplied. Results of the Wilcox rank sum test 

indicate a significant difference (probability value = 

0.04), which indicates that the median concentration 

of nitrate in ground water beneath developed land is 

greater than that in ground water beneath undeveloped land. Therefore, land use is likely the major 

controlling factor on nitrate concentrations in 

bedrock aquifers.

Pesticides and Volatile Organic Compounds

Of the 100 sites represented in this report, 11 had 

samples for selected pesticides and VOC's during 

1970-90. Six of these sites are in Connecticut, one is 

in New York, and four are in New Jersey. Concentrations of all compounds were at or below the analytical 

detection limits (table 12) except for diazinon, which 

was detected at a concentration of 0.03 |ig/L at the 

New York site in an urban setting (Schenectady 

County).

Surface Water

This section presents results of the analyses of 

nutrient, suspended-sediment, and pesticide data 

from 56 surface-water sites. It includes nutrient-yield 

estimates for selected sites and relates them to rates of 

input from agricultural, atmospheric, geologic, and 

sewage sources; it also compares suspendedsediment concentrations and yields among the sites

42 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
Table 12. Detection limits of selected pesticides and 

volatile organic compounds for which ground-water 

samples from the Hudson River basin were analyzed, 

1970-90.

[Detection limits are in micrograms per liter]

Constituent Detection limit

Pesticides

2, 4-D, Total

2, 4-DP, Total

2, 4, 5-T, Total

Aldrin, Total

Aldrin, Dissolved

AmetrynE

Atrazine, Total

Bromoform, Total

Chlordane Total

Chlordane, Dissolved

CYANAZINE

ODD, Total

ODD, Dissolved

DDE, Total

DDE, Dissolved

DDE, Dissolved

DOT, Total

DOT, Dissolved

Diazinon, Total

Dieldrin, Total

Dieldrin, Dissolved

Endosulfan I, Total

Endrin, Total

Endrin, Dissolved

Ethion, Total

Heptachlor, Dissolved

Heptachlor, Total

Heptachlor Epoxide, Dissolved

Heptachlor Epoxide, Total

Lindane, Dissolved

mirex, Dissolved

Mirex, Total

Parathion Total

Perthane, Total

Prometone, Total

Prometryne, Total

Propazine

Silvex, Total

Simazine, Total

Simetryne, Total

Toxaphene, Total

0.01

0.01

0.01

0.001

0.01

0.1

0.1

0.2

0.1

0.1

0.01

0.001

0.01

0.001

0.01

0.01

0.001

0.01

0.01

0.01

0.01

0.001

0.001

0.01

0.01

0.01

0.01

0.001

0.01

0.01

0.001

0.01

0.01

0.01

0.01

0.1

0.2

0.1

0.1

0.1

Volatile Organic Compounds

Chlorobenzene 

Chlorodibromomethane, Total 

Chloroethane

Dichlorobromomethane, Total 

Methylchloride, Total 

Methylene chloride, Total

0.2

0.1

0.1

0.1

0.01

0.01

that have adequate data and discusses pesticidedetection rates and median pesticide concentrations 

in relation to land use.

Nutrients

Nutrient concentrations in surface water are related 

to discharge, season, land use, and population density 

and are used to calculate yields (mass per area) and 

transport rates (mass per time unit). The following 

paragraphs present estimated yields for selected sites 

with daily discharge data; it also includes mass 

balances and yields for total nitrogen, dissolved 

nitrate, and total phosphorus for comparison with 

inputs from atmospheric and, agricultural sources, 

and from treated wastewater.

Concentration in Relation to Discharge

Plots of nutrient concentration in relation to 

discharge at sites representing differing land uses can 

help identify whether the nutrients are derived from 

point or nonpoint sources. If nutrient concentrations 

increase with increasing discharge, nonpoint sources 

are probably the main control, but if the concentrations decrease with increasing discharge, point 

sources are probably the main control. This section 

presents nutrient concentration-to-discharge relations 

for five sites representing:

1. a small (less than 250 mi2) agricultural watershed 

(Wappinger Creek near Wappingers Falls, N.Y. 

site 45),

2. a large (greater than 1,000 mi2) agricultural

watershed (Mohawk River at Crescent Dam, N.Y. 

site 27a),

3. a small (less than 250 mi2) urban watershed 

(Hoosic River below Williamstown, Mass, site 

13),

4. a small (less than 100 mi2) forested watershed 

(Esopus Creek at Shandaken, N.Y. site 32), and

5. a large (greater than 1,000 mi2) forested watershed 

(Hudson River at Corinth, N.Y. site 5).

The Hoosic River site below Williamstown, Mass, 

has no data on total nitrogen; therefore, the Hoosic 

River site near North Petersburg, N.Y. (site 14) was 

used to represent urban conditions for total nitrogen. 

The following discussion focuses mainly on the 

relation between discharge and dissolved nitrate, total 

nitrogen, and total phosphorus concentrations at these 

five sites and also includes dissolved ammonium

Analysis Of Nutrient, Pesticide, Volatile Organic Compound, And Suspended-sediment Data 43
concentration at the five sites from which more than 

30 samples were available.

Small Agricultural Watershed. Concentrations of 

most nutrient species in the small agricultural watershed (Wappinger Creek near Wappingers Falls, site 

45) increase with increasing discharge. This watershed is about 36 percent agricultural land and has 

little urban area (less than 5 percent); most of the 

remaining watershed area is forested. In general, 

nitrate concentrations at this site increase with 

increasing discharge (fig. 19A), and the concentration-to-discharge relation shows little seasonal 

variability. The relation for total nitrogen at this site 

is similar to those for nitrate because dissolved nitrate 

constitutes most of the total nitrogen. In contrast, 

dissolved ammonium slightly increases with increasing discharge during discharges less than 200 ft3/s

and decreases with increasing discharges of 200 to 

1,000 ft3/s. Dissolved ammonium concentrations 

decrease with increasing discharge at this site and 

most other sites in the Hudson River basin, regardless 

of land use. The total phosphorus concentration at 

this site increases with increasing discharge at 

discharges greater than 300 ft3/s. These results 

indicate that nutrient concentrations in surface water 

in this agricultural watershed are controlled largely 

by nonpoint sources.

The relations between nutrient concentrations and 

discharge in other agricultural watersheds that have 

daily-discharge records confirm this direct correlation; this pattern was observed for dissolved nitrate, 

total nitrogen, and total phosphorus at two of the 

other three agricultural watersheds: Mohawk River at 

Fonda (site 20) and Schoharie Creek at Burtonsville 

(site 25). The third site, the Wallkill River near

DC 

UJ

~

O a:

H W

< 0-

10

0.1

DISSOLVED NITRATE

LOWESS

smooth line

10 100 1,000 10,000

O DC

F uj

^ DL

CE CO

£ 2 0.1

ui ;$

°I

z 

0.01

DISSOLVED AMMONIUM *

2 observations below 0.01 milligrams per liter

10 100 1,000 10,000

DISCHARGE, IN CUBIC FEET PER SECOND

A. SMALL WATERSHED

10

0.1

TOTAL NITROGEN

10 100 1,000 10,000

0.1

0.01

TOTAL PHOSPHORUS

1 observation below 0.01 milligram per liter

 4 *-

10 100 1,000 10,000 

DISCHARGE, IN CUBIC FEET PER SECOND

Figure 19A. Nutrient concentrations as a function of discharge in a small agricultural watershed (181 mP, Wappinger 

Creek near Wappinger's Falls, N.Y.), 1970-90.

44 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
Rosendale (site 42), differs from the other two 

agricultural sites in that more than 5 percent of its 

area is urban, its 1980 population density exceeded 

200 per mi2, and concentrations of dissolved nitrate, 

total nitrogen, and total phosphorus change little with 

increasing discharge. These results confirm that 

nutrients in streams draining agricultural watersheds 

are derived mainly from nonpoint agricultural 

sources, although they could be partly derived from 

urban point sources in agricultural watersheds with 

an elevated population density and extensive 

urbanization.

Large agricultural watershed. The Mohawk River 

at Crescent Dam drains a large area (greater than 

3,000 mi2) that is nearly 34 percent agricultural and 

about 6 percent urban; the rest is mainly forested 

land. Nutrient concentrations near the outlet of the 

Mohawk River (at site 21 A, Mohawk River at

10

cr LII

z~ zi

O QC 

C 111 

<C CL 

|«

Z << 

UJ 5

S l

8^

0.1

DISSOLVED NITRATE

0.1 10 100

O DC

^ III

< QOC CO

m ^

0.01

DISSOLVED ./*** . 

AMMONIUM ** 0 fS 9 .

0.1 1 10 100

DISCHARGE, 

IN THOUSANDS OF CUBIC FEET PER SECOND

B. LARGE WATERSHED

Crescent Dam) are not strongly related to discharge. 

The LOWESS line for the relation between dissolved 

nitrate concentration and discharge is flat, as is the 

line for total nitrogen (fig. 19B). The LOWESS line 

for ammonium implies a direct correlation at 

discharges less than 3,000 ft3/s; but the wide scatter 

of data makes any apparent trend difficult to discern. 

The line for total phosphorus has a mild U shape - at 

daily discharges of 4,000 to 10,000 ft3/s, the concentration decreases with increasing discharges, and at 

discharges of 10,000 to 30,000 ft3/s, it increases with 

increasing discharge. These results indicate that 

nutrients at this site are derived from a combination 

of point and nonpoint sources.

The relation between some nutrients and discharge 

at this site changes seasonally (fig. 20A). From 

November through February, dissolved nitrate 

concentration generally decreases with increasing 

discharge, whereas from March through June, it

10

0.1

TOTAL NITROGEN

 t

0.1 10 100

0.1

0.01

TOTAL PHOSPHORUS

-r.-

0.1 1 10 100

DISCHARGE, 

IN THOUSANDS OF CUBIC FEET PER SECOND

Figure 19B. Nutrient concentrations as a function of discharge in a large agricultural watershed (3,440 m?, 

Mohawk River at Crescent Dam, N.Y.), 1970-90.

Analysis Of Nutrient, Pesticide, Volatile Organic Compound, And Suspended-sediment Data 45
O

a: a:

I- UJ

O 

o

b <3

O 

C/3 w

Q

1.0

0.8

0.6

0.4 

0.1

A. BY SEASON AT CRESCENT DAM

March-June 

July-October /*"

NovemberFebruary

1 10 100

DISCHARGE, 

IN THOUSANDS OF CUBIC FEET PER SECOND

1.0

0.8

0.6

0.4

0.2 

0.1

B. 1970-1990 

Crescent Dam (Site 27A)

- Cohoes (Site 27B)

1 10 100

DISCHARGE, 

IN THOUSANDS OF CUBIC FEET PER SECOND

Figure 20. Dissolved nitrate concentration as a function of discharge at a large agricultural watershed site (Mohawk River 

outlet): A. At Crescent Dam, based on season, 1970-90; B. At Crescent Dam and Cohoes, based on all 1970-90 data.

generally increases with increasing daily discharges. 

Dissolved nitrate concentration from March through 

June is also higher than the concentration observed 

from November through February at nearly all 

discharges. From July through October, the concentration generally decreases with increasing discharge, 

especially at discharges above 2,000 ft3/s. The 

seasonal patterns of total nitrogen concentrations at 

this site are similar to those for dissolved nitrate, but 

the relations for dissolved ammonium and total 

phosphorus do not change seasonally. The cause of 

the seasonal variability in the dissolved nitrate-todischarge relation at this site is uncertain, but the 

positive correlation from March through June could 

reflect the predominance of nonpoint agricultural 

runoff during the spring, whereas the negative correlation during the remaining months could reflect the 

predominance of urban point sources. These results 

indicate that nonpoint sources of nutrients have a 

greater effect on dissolved nitrate and total nitrogen 

concentrations from March through June at this site 

than at any other time.

The relation of dissolved nitrate to discharge at this 

site (site 27A) differs from the relation for the 

Mohawk River at Cohoes (site 27B), 2 mi upstream. 

At flows less than 20,000 ft3/s, the dissolved nitrate 

concentration at Crescent Dam is higher than at 

Cohoes (fig. 20B). Only a few samples from the 

Mohawk River at Cohoes site were analyzed for 

dissolved ammonium, total nitrogen, or total phosphorus; thus, differences in the relation of concentration to

discharge between the two sites could not be assessed. 

All Crescent Dam samples were collected before 1979, 

whereas nearly all of the Cohoes samples were 

collected after 1986; thus, the difference in nitrate 

concentration between these sites could reflect either a 

change in nitrate source between 1979-86 or differences in sampling locations over time.

Urban watershed. Nutrient concentrations generally 

decrease with increasing discharge at the two urban 

watersheds for which nutrient data were available - 

Hoosic River below Williamstown (site 13) and 

Hoosic River near North Petersburg (site 14). 

Dissolved nitrate and total phosphorus concentrations 

generally decrease with increasing discharge at the 

Williamstown site, although the concentration-todischarge plot for nitrate shows considerable scatter 

(fig. 21 A). Although total nitrogen data from this site 

are unavailable, the total nitrogen concentration at the 

North Petersburg site generally decreases with 

increasing discharge (fig. 21 B). Because the Hoosic 

River watershed above these two sites is about 10 

percent urban land and 15 percent agricultural land, 

with the remaining mostly forested land, these 

relations indicate that nutrient concentrations in the 

Hoosic River are probably associated with urban point 

sources. Turk and Troutman (1981) suggested that 

shale bedrock in the Hoosic River basin may contribute significant amounts of phosphorus to streams 

during periods of high discharge, but the general 

decrease in total phosphorus concentration with

46 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
10

ccLII

- b

z -J

O CC F 111 < Qc w

0.1

DISSOLVED NITRATE

LOWESS 

smooth line

10 100 1,000 10,000

_

O CC

F 111 < QCC (f)

0.1

0.01

TOTAL PHOSPHORUS

10 100 1,000 10,000

A. HOOSIC RIVER BELOW 

WILLIAMSTOWN, MASS.

10

O cc

P LU

< Q0.1

TOTAL NITROGEN

10 100 1,000 10,000 

DISCHARGE, IN CUBIC FEET PER SECOND

B. HOOSIC RIVER NEAR 

NORTH PETERSBURG, N.Y..

Figure 21. Nutrient concentration as a function of 

discharge in two urban watersheds, 1970-90: 

A. Dissolved nitrate and total phosphorus concentration at Hoosic River below Williamstown, Mass, 

(site 13). B. Total nitrogen at Hoosic River near North 

Petersburg, N.Y. (site 14).

increasing discharge indicates that nonpoint geologic 

sources have only a minor effect, if any, on total 

phosphorus concentrations in the Hoosic River.

Forested watersheds . Concentration of dissolved 

nitrate and total nitrogen generally increase with 

increasing discharge in both large and small forested 

watersheds in the basin, as exemplified by Esopus 

Creek at Shandaken (site 32), a small watershed 

dominated by forest in the Catskill Mountains, 

where dissolved nitrate and total nitrogen concentrations increase with increasing discharge (fig. 22A). 

Total phosphorus concentration, in contrast, shows 

little change with discharge, partly because the total 

phosphorus concentrations in nearly half the 

samples collected from this site were at or near the 

detection limit of 0.01 mg/L as P . These patterns are 

similar in large forested watersheds, as seen in the 

corresponding plots for samples from the Hudson 

River at Corinth (site 5), a large watershed 

dominated by forest in the Adirondack Mountains 

(fig 22B). As at site 32, dissolved nitrate and total 

nitrogen concentrations at this site generally 

increase with increasing discharge, and total 

phosphorus concentration changes little with 

increasing discharge, because most of the concentrations were at or below 0.01 mg/L. These relations 

indicate that nitrogen in streams that drain forested 

watersheds are derived mainly from nonpoint 

sources.

A similar pattern of increasing dissolved nitrate 

concentration with increasing discharge was found 

by Murdoch and Stoddard (1992) for small forested 

watersheds in the Catskill Mountains; dissolved 

nitrate concentrations at these sites tend to be highest 

during high flows in the late winter and early spring. 

Because agricultural and urban land generally constitutes less than 2 percent of these basins, Murdoch 

and Stoddard (1992) attributed the observed 

dissolved nitrate concentrations to atmospheric 

deposition, rather than to agricultural, urban, or 

residential sources.

Concentration in Relation to Time

Nitrate concentrations in streams draining small 

forested watersheds in the Catskill Mountains 

increased gradually during 1920-70 and sharply 

after 1970 (Murdoch and Stoddard, 1992), as 

indicated by the trend line for two representative 

streams with long-term records (fig. 23). Much of

Surface Water 47
A. SMALL WATERSHEDS 

ESOPUS CREEK AT SHANDAKEN

B. LARGE WATERSHED 

HUDSON RIVER AT CORINTH

10

DC 

LLJ

z" m

O cc

^ Qpc co

0.1

10

DISSOLVED NITRATE

LOWESS 

smooth line

 : * 4»>^'

 * * /*&JF^

 .f^+^v .. 

 * ***.*'*? * *

10 100

O DC

h- L"-1

^ QDC CO

0

0.1

TOTAL NITROGEN

10 100

O cr

< Qpc co

0.1

0.01

TOTAL PHOSPHORUS

56 observations below 0.01 milligrams per liter

10 100

DISCHARGE, 

IN CUBIC FEET PER SECOND

1,000 10,000

1,000 10,000

1,000 10,000

10

0.1

10

DISSOLVED NITRATE

10 100

0.1

0.1

TOTAL NITROGEN

2 observations below 1,000 cubic feet per second

not shown

10 100

0.01

TOTAL PHOSPHORUS

36 observations below 0.01 milligrams per liter

10 100

DISCHARGE, 

IN THOUSANDS OF CUBIC FEET PER SECOND

Figure 22. Concentration of dissolved nitrate, total nitrogen, and total phosphorus as a function of discharge at two 

forested watersheds, 1970-90: A. Esopus Creek at Shandaken, N.Y. (59.5 mP). B. Hudson River at Corinth, N.Y. 

(2,755 mi2)

48 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
0) TI

of

2.5

Q. (0

O- N> 

O "

O CD

JD =* 

=. 0) 

® CD

Oo 

5 §

® O

^ CD

a 2

CD « 

SO

o O

Q. (D

II

3 8

It 

II

QL W 

002, 

O <D 

QL (U 

Q. CO 

9J ® 

P3

 OmCO

o o

COO

CD 

CD 

7?

DISSOLVED NITRATE CONCENTRATION, 

IN MILLIGRAMS PER LITER

DIS

0 - 

IV)

o -

10 KILOMETERS

- 0 

IV) o

4^ 

 o2

m 

en

Schoharie Creek at Prattsville, NY

O

Esopus Creekat Coldbrook, NY j

Basin boundary

mX o05Oz

ii

-
the increase at these sites is attributed by Murdoch 

and Stoddard (1992) to the increase in nitrate 

concentrations during storms; changes in nitrate 

concentrations during low discharges have been 

insubstantial. These data indicate that nitrate 

concentrations in streams draining small (less than 

250 mi2) forested watersheds have increased over 

time. The sparsity of data for other types of sites 

(including agricultural, urban, and mixed) and for 

large watersheds prevents basinwide assessment of 

time trends for nutrients.

Concentration in Relation to Land Use and 

Population Density

The relation between nutrient concentrations and 

land use is discussed in this section through statistical 

comparisons of median nutrient concentrations at (1) 

six selected sites with daily discharge records, and (2) 

a larger group of sites, some with daily discharge 

records and some without. The median values are 

compared among land-use categories and correlated 

with population density.

The sites selected for land-use and population 

correlations represent (1) two agricultural watersheds-the Mohawk River at Fonda (site 20) and 

Wappinger Creek (site 45) for four nutrients 

(dissolved nitrate, total nitrogen, dissolved 

ammonium, and total phosphorus), (2) two urban 

watersheds-Hoosic River below Williamstown, 

Mass, (site 13) for dissolved nitrate and total 

phosphorus, and Hoosic River at North Petersburg 

(site 14) for dissolved ammonium and total nitrogen, 

and (3) two forested watersheds-Esopus Creek at 

Shandaken (site 32) and East Branch of the Sacandaga River (site 3) for all four nutrients. These sites 

together represent the major land uses and environmental settings within the study area.

The median concentrations of dissolved nitrate and 

total nitrogen for agricultural or urban watershed sites 

are twice to three times the median concentrations for 

the forested watersheds (fig. 24), as are the median 

dissolved ammonium concentrations for the Mohawk 

River at Fonda (agricultural) and Hoosic River at 

North Petersburg (urban) sites. The median concentration of dissolved ammonium for Wappingers 

Creek (agricultural) is similar to that for East Sacandaga River (forested), however. Median total 

phosphorus concentrations for the Mohawk River at 

Fonda (agricultural) and Hoosic River at North

Petersburg (urban) are 10 to 30 times higher than 

those for the two forested sites. In summary, median 

concentrations of all nutrients (except dissolved 

ammonium) for the agricultural- and urban- watershed sites greatly exceed those medians for the 

forested watershed sites.

The purpose of the basinwide comparison of 

median nutrient concentrations is to show broad 

trends among watersheds that differ in land use and 

population density. Sites that were included in the 

basinwide comparison were those for which 10 or 

more analyses for a constituent were available (site 

locations are shown in fig. 25; nutrients represented 

at each site are listed in table 13). If the drainage areas 

of two sites selected overlapped by 50 percent or 

more, the site with the larger drainage area was 

excluded. Because only a few urban or mixed sites 

had sufficient data, results from these sites were 

combined for the analysis.

Comparison of median dissolved nitrate, total nitrogen and total phosphorus concentrations among 

agricultural, urban/mixed, and forested sites indicates 

that median concentrations of total nitrogen and total 

phosphorus at agricultural and urban/mixed sites are 

similar to one another and exceed the median concentrations at forested sites by a factor of 2 for total 

nitrogen and a factor of 7 for total phosphorus. Median 

concentrations of dissolved nitrate, in contrast, do not 

differ significantly among sites (fig. 26).

Nonparametric Spearman-rank correlations 

between median dissolved nitrate, total nitrogen, and 

total phosphorus concentrations and site characteristics (including predominant land use and population 

density in the watershed) indicate the characteristic 

with which all nutrients are most closely related is 

population density. Median concentrations of all 

nutrients are significantly (at the 0.05 level) and 

positively related to percent agricultural land and 

population density and negatively related to percent 

forest (table 14); median total nitrogen and total 

phosphorus concentrations are significantly and 

positively related to percent urban land. The highest 

correlations are for the relation between population 

density and (1) median total nitrogen and (2) median 

total phosphorus. Population density also is 

positively correlated with percent urban land and 

percent agricultural land, and negatively correlated 

with percent forest land (table 14).

50 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
i \y

DC

LU

0 cr

i II 1 < o.

DC CO

-1 1

z o

o =! °i

z

n 1

; DISSOLVED NITRATE ;

A A A B B -

_

: 0.71 1 0.72 1 1 : 

1 1 0.60 I i

' i 0.31 1

0.25 j- |

T 1

10

1 2 3a 4 5 

SITE

0.1

TOTAL NITROGEN

A B AB C C

1.0

1.3

0.51 0.61

1 2 3b 4 5 

SITE

IU

DC 

LU

0 cr 1

P LU 

"t QDC CO

z <

LU rf

O

UCD

03 0.1 °i

z

0-01

: :

I DISSOLVED AMMONIUM I

\ A B A C B ~

r I i

: ! i i

- 0.21 I - 1 1

1 1 O- 14 1 ri

: T 0.062 1 T I 0- 067 ! \

T 0.03 | '

1

10

DC 

LU

z" in .

0 cr 1

P LU

"t QDC CO

Lu <

O (TJ

Z |

z

A ^4

1 2 3b 4 5

: 

I DISSOLVED AMMONIUM

ABA

! 1

- 0.21 | -

i 1 °-14

: °-062 |

I (

1 ? 3h

Agricultual Urban Forested Anrir,iit,ifli iir'han

 .

;

C B ~

-

_

 '

1 °-067 l -

).03 | 1

4 "TOR

FnroctnH

SITE AND LAND USE SITE AND LAND USE

EXPLANATION

Median 

Concentration

2.0

Percentile 

90

75

50

25

10

SITES

Agricultural

1. Mohawk River at Fonda, NY

2. Wappinger Creek near Wappingers 

Falls, NY

Urban

3a. Hoosic River below Williamstown, MA 

3b. Hoosic River near North Petersburg, NY

Forested

4. Esopus Creek at Shandaken, NY

5. East Sacandaga River at Griffin, NY

A B AB C differing letters indicate 

significant difference in 

median concentrations, 

according to KruskalWallis test

< less than

Figure 24. Median and range of dissolved nitrate, total nitrogen, dissolved ammonia, and total phosphorus concentrations at 

five sites in the Hudson River basin in eastern New York and adjacent States, by land use, 1970-90.

Surface Water 51
76' 75 c 74°

44

43'

41'

______7£ 

7 T

Adirondack 

Mountains VERMONT

EXPLANATION

^ ..^ ..^ Basin boundary 

$17 Dissolved nitrate 

®34 Total nitrogen

Total phosphorus s41

0 10 20 30 40 50 MILES

I I I I I I

I I I I I I

0 10 20 30 40 50 KILOMETERS

C a t s k i I I 

Mountains

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45 ° 30', central meridian -74°

Figure 25. Locations of surface-water sites from which data were available for basinwide comparison of nutrient 

concentrations. (Site names are given in table 13).

52 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
Table 13. Sites used for basinwide comparison of median nutrient concentrations.

[DN = dissolved nitrate, TN = total nitrogen, TP = total phosphorus. Site locations are shown in fig. 25]

Site 

no.

1

2

3

4

5

8

10

11

14

15

16

17

18

19

20

23

25

32

33

34

35

37

38

39

40

41

42

44

45

47

48

56

Site Name

Hudson River at North Creek N.Y.

Schroon River at Riverbank N.Y.

East Branch Sacandaga River at Griffin N.Y.

Sacandaga River at Hadley N.Y.

Hudson River at Corinth N.Y.

Batten Kill at Middle Falls N.Y.

Clover Mill Brook on Shaw Hill Rd near Rock City Falls N.Y.

Kayaderosseras Creek at Saratoga Springs N.Y.

Hoosic River at North Petersburg N.Y.

Hoosic River at Eagle Bridge N.Y.

Hudson River at Waterford N.Y.

Mohawk River near Utica N.Y.

Utica Water Supply Intake on West Canada Creek N.Y.

Cayadutta Creek at Fonda N.Y.

Mohawk River above State Highway 30 at Fonda N.Y

Schoharie Creek at Breakabeen N.Y.

Schoharie Creek at Burtonsville N.Y.

Esopus Creek at Shandaken N.Y.

Hollow Tree Brook at Lanesville N.Y.

Esopus Creek at Saugerties N.Y.

Rondout Creek above Red Brook at Peekamoose N.Y.

Wallkill River at Outflow of Lake Mohawk at Sparta N.J.

Wallkill River at Franklin N.J.

Wallkill River near Sussex N.J.

Papakating Creek at Sussex N.J.

Black Creek near Vernon N.J.

Wallkill River near Rosendale N.Y.

Twaalfskill near Highland N.Y.

Wappinger Creek near Wappingers Falls N.Y.

Fishkill Creek at Beacon N.Y.

Moodna Creek near New Windsor N.Y.

Winebrook Hills Plant Intakeon Hudson River N.Y.

Land Use

Forest

Forest

Forest

Forest

Forest

Agricultural

Forest

Agricultural

Urban

Mixed

Mixed

Agricultural

Forest

Mixed

Agricultural

Mixed

Agricultural

Forest

Forest

Forest

Forest

Urban

Urban

Mixed

Agricultural

Mixed

Agricultural

Agricultural

Agricultural

Mixed

Mixed

Forest

Nutrients for which 

data are available

DN,TN,TP

DN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN

DN,TN

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN

DN,TN,TP

DN

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

DN,TN,TP

Median nutrient concentrations generally increase 

with increasing population density at sites representing 

watersheds with a population less than 250 per mi2 

(fig. 27). Although the median nutrient concentrations 

for watersheds with a population density exceeding 

300 per mi2 appear to be lower than those for watersheds with intermediate population densities (150 to 

250 per mi2), only six watersheds have a population 

density greater than 300 per mi2 . Four of the six sites 

with population density in excess of 300 per mi2 are in 

the upper reaches of the Wallkill River (in northern 

New Jersey), where the low nutrient concentrations are 

probably the result of land use, hydrologic or geologic 

conditions, or use of non-USGS analytical methods. 

The available data are insufficient for estimation of

Table 14. Spearman nonparametric correlation coefficients 

for correlation of basinwide median nutrient concentrations 

with land use and population density.

[Number in parentheses is significance level. Coefficient for 

population density is based on sites with dissolved nitrate 

analyses.]

Basin 

characteristic

Percent 

urban

Percent 

agricultural

Percent 

forested

Population 

density

Spearman non-parametric correlation coefficient 

with basin characteristic

Dissolved 

Nitrate

0.31 

(0.083)

0.63

-0.47

0.38 

(0.033)

Total 

Nitrogen

0.73 

(<0.01)

0.66

-0.76

0.76

Total Phosphorus

0.76 

(<0.01)

0.74

-0.77

0.79

Population 

density

0.95 

(<.01)

0.62

-0.87

-

Surface Water 53
median nutrient concentrations for watersheds with 

population densities greater than 300 per mi2 .

A comparison of median nutrient concentrations 

for the six selected sites that have daily discharge 

records - Mohawk River at Fonda, Wappinger Creek 

at Wappinger Falls, Esopus Creek at Shandaken, East 

Branch of the Sacandaga River at Griffen, Hoosic 

River below Williamstown (for dissolved nitrate and

total phosphorus), and Hoosic River at North Petersburg-with medians for sites used in the basinwide 

comparison indicates that the median nutrient 

concentrations for the six sites are generally representative of the entire basin. Both groups of sites show 

the same general trend of increasing dissolved nitrate, 

total nitrogen, and total phosphorus concentrations 

with increasing population density.

10

DC

LU

2f =i 

O DC

P LU 

< Qpc co SI i§

8^ 0.1

0.01

: A. DISSOLVED NITRATE

: 0.72 1 (

: % 0.5 1 

: 1 

- ^ Detection limit

A AB

n=11 n=9

:

0.36 J "

;

B

n=12

10

Agricultural Urban and Mixed Forested 

LAND-USE CATEGORY

0.1

0.01

B. TOTAL NITROGEN

1.2 1.4

0.6

Detection limit

A 

n=11

A

n=9

B

n=9

Agricultural Urban and Mixed Forested 

LAND-USE CATEGORY

DC

LU

O c 0.1

P LU 

< CL

o = O g

O d °-01

0.001

C. TOTAL 

PHOSPHORUS

0.08 0.07 f

0.01

Detection limit

A 

n=9

A

n=9

B 

n=10

EXPLANATION

1.2 I Median concentration

A AB C Differing letters indicate 

significant difference in 

median concentration, 

according to KruskalWallis test

n = 9 Number of samples

Agricultural Urban and Mixed Forested 

LAND-USE CATEGORY

Figure 26. Range of dissolved nitrate, total nitrogen, and total phosphorus concentrations among sites grouped 

by land use for basinwide comparison.

54 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
1 .O

DC -) 2

UJ 1-

Z -1

0 cr

££ 0.9

Eg|i

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-

-

-

-

i

)

L

*<

&

1 1 1 | 1 1 1 | 1 1 1 | 1 1 1 |

DISSOLVED NITRATE

Note: one outlying point not shown o

o 

o

09 o °

o o

0 o o o ° 9

0 o

o s Detection limit

, , , i , , , l , , , l , , . l

i i i

-

-

_

-

o

-

-

-

0

-

1 1 1

100 200 300 400 500

cc UJ 20*""

HZ -I

0 cr

h- UJ 1 c

^ Q_ I .O

cc co t; 2

|o 1.0

8 i '

-_ < ? 0.5

0

( 

f\ c U.b

cr

UJ

Si 0.4

P HI

< flee CO

^ 2 0.3

UJ 5

^5

OH 02

0 ^

z

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m

i i i | i | i i i | i i i | i i i

I TOTAL NITROGEN I

^_ Note: two outlying points not shown J

_

o -

: o ° i

 

: . o ° o :

o

1 o o °. 0 -_

0

± °o ° o

f. _

" , , , 1 , , , 1 , , , 1 , , , 1 , , , "

D 100 200 300 400 50

i i i I i i i I i i i I i i i I i i i 

TOTAL PHOSPHORUS

~ Note: one outlying point not shown ~

.

_ _

-

- 0 

*

_ _

o

o o

o

- o -

o ° o 0

'**?. . <} , * ° , , , 1 , , , 1 , °, , "

0 100 200 300 400 500 

POPULATION DENSITY PER SQUARE MILE 

EXPLANATION

 Site used in basinwide 

comparison

o Other site

Figure 27. Median concentration of dissolved nitrate, total 

nitrogen, and total phosphorus in relation to watershed 

population at surface-water sites in the Hudson River basin.

Yields

Nitrogen and phosphorus yields (mass per unit 

area) from watersheds were calculated and related to 

the rates of inputs to illustrate the major patterns of 

nutrient movement through the Hudson River basin. 

The effects of treated wastewater, agricultural, and 

atmospheric sources on nutrient yield also were 

evaluated. Average annual yields were calculated for 

16 sites from data collected during 1970-80; 

additional yield estimates were also calculated for 

three of these sites from data collected during 1981- 

1990 (table 15, fig. 28). The yields discussed here 

are based on the averages for 3 years-one in which 

the annual mean flow was ranked in the upper 10 

percent of all annual mean flows, one in which the 

annual mean flow was equal to the long-term mean 

annual flow, and one in which the annual mean flow 

was ranked in the lower 10 percent of all annual 

mean flows. The discussion is based largely on 

yields calculated for 1970-80 because nearly all the 

data were collected during this period. Two yields 

were calculated for the three sites with data collected 

during 1970-90; the first is based on data collected 

during 1970-80, the second on data collected during 

1981-90. The yield reported for 1970-80 for site 25 

(Schoharie Creek at Burtonsville) is based on 

samples collected during 1970-90; the additional 

samples collected at this site from 1981-90 were 

needed to ensure a sufficient number of samples for 

computation of yields.

Yields generally are calculated from data representing a wide range of flow conditions, including 

high flows. Nearly all of the yields presented here are 

based on data sets representing four or more samples 

collected during a flow with an exceedence probability of less than 10 percent; most estimates include 

samples collected in the upper 1 percent of flow 

duration (table 15). The estimates for most sites are 

based on 20 or more samples, and the standard errors 

of rate estimate are generally less than 25 percent 

(tables 15, 16). One exception is site 23 (Schoharie at 

Breakabeen), at which all the standard errors of 

prediction exceed 25 percent (table 16); therefore, the 

estimated yields for this site were used only for 

comparison with a downstream site (site 25, Schoharie Creek at Burtonsville). Similarly, the estimated 

yields for site 20 (Mohawk at Fonda) are based on 

only 13 samples collected during 1981-90, but they 

allow some comparison with the yields calculated for 

this site from 1970-80 data.

Surface Water 55
Table 15. Number and flow characteristics of samples used to calculate average annual yields. 

[Site locations are shown in fig. 28.]

Number of Samples

Site 

Number Constituent

Exceedence Probability 

for samples representing

Representing 

discharge exceeded 

less than 10 percent Maximium 

Total of time Discharge

Minimum 

Discharge

Years

Of sample 

collection

Used in 

computation of 

transport rates

A. DATA BASED ON 1970-80 SAMPLING

5

6

7

13

14

16

20

23

25

26

27A

28

32

Dissolved nitrate

Total phosphorus

Dissolved ammonium

Total nitrogen

Dissolved nitrate

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Dissolved ammonium

Dissolved nitrate

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Dissolved ammonium

Total nitrogen

Dissolved nitrate

Total phosphorus

Dissolved ammonium

Dissolved nitrate

Total phosphorus

66

do.

49

60

69

do.

88

147

145

92

49

do.

40

103

100

101

do.

do.

37

67

do.

24

29

24

32

do.

29

80

do.

do.

108

169

168

97

87

118

116

58

125

121

12

do.

9

15

19

do.

17

28

27

15

7

do.

5

17

16

29

do.

do.

5

9

do.

4

6

4

6

8

6

12

do.

do.

10

24

do.

17

16

21

20

9

13

10

.68

do.

do.

.11

do.

do.

.38

do.

do.

do.

3.00

do.

.52

.25

.52

.38

do.

do.

.11

do.

do.

0.36

0.24

0.36

0.92

do.

0.90

1.80

do.

do.

0.62

do.

do.

do.

0.65

do.

do.

2.00

1.70

2.50

83

do.

do.

85

do.

do.

85

do.

do.

do.

91

do.

92

91

do.

99.8

do.

do.

92

94

do.

98.7

do.

do.

99.9

do.

do.

93

do.

do.

98

do.

do.

do.

97

98

do.

97

99

do.

1970-75

do.

do.

1972-78

do.

do.

1971-79

do.

do.

do.

1970-74

do.

1971-75

do.

do.

1977-80

do.

do.

1971-75

1970-75

do.

1971-76

1974-76

do.

1971-90

do.

1970-90

1973-79

do.

do.

1971-78

do.

do.

do.

1970-80

do.

do.

do.

1970-80

do.

1978,75,81

do.

do.

1978,75,81

do.

do.

1978,75,81

do.

do.

do.

1973,77,81

do.

1973,77,81

do.

do.

1978,82,81

do.

do.

1978, 89, 88

do.

do.

1979,76,81

do.

do.

1978, 70, 81

do.

do.

1978,70,81

do.

do.

1978,83,81

do.

do.

do.

1978,83,81

do.

do.

do.

1972,71,81

do.

56 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
Table 15. Number and flow characteristics of samples used to calculate average annual yields (cont.).

Number of Samples

Site 

Number

42

43

45

B. DATA

20

28

32

Constituent

Total nitrogen

Dissolved nitrate

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Exceedence Probability 

for samples representing

Representing 

discharge exceeded 

less than 1 0 percent Maximium 

Total of time Discharge

21

32

33

22

30

30

36

71

66

2

do.

5

1

4

do.

6

14

11

5.6

.53

do.

10.0

.50

do.

1.33

1.15

1.33

Minimum 

Discharge

88.5

do.

do.

90.91

do.

do.

86.3

do.

do.

Years

Of sample 

collection

1971-75

1970-75

do.

1971-75

do.

do.

1971-75

1969-75

do.

Used in 

computation of 

transport rates

1972,71,81

do.

do.

1972,71,81

do.

do.

1975,82,81

do.

do.

BASED ON 1981-90 SAMPLING

Total nitrogen

Dissolved nitrate

Total nitrogen

Dissolved nitrate

Dissolved ammonium

Total phosphorus

Total nitrogen

Dissolved nitrate

Total phosphorus

Dissolved ammonium

13

do.

42

do.

do.

do.

45

54

45

46

7

do.

5

do.

do.

do.

4

7

4

do.

.45

do.

.65

do.

do.

do.

6.7

1.1

6.7

do.

98

do.

96

do.

do.

do.

99

do.

do.

do.

1988-90

do.

1981-90

do.

do.

do.

1981-90

do.

do.

do.

1978,89,88

do.

1978,83,81

do.

do.

do.

1972,71,81

do.

do.

do.

The relations among average annual yield and 

watershed characteristics indicate that nutrient yield 

is a function of agricultural land use and population 

density. Average annual yields of dissolved nitrate, 

total nitrogen, and total phosphorus based on 1970- 

80 data generally increase with increasing percent 

agricultural area and with increasing population 

density (fig. 29, p. 59). The highest average annual 

nutrient yields were in watersheds with the largest 

amount of agricultural land and the highest population densities, including sites 20 (Mohawk River at 

Fonda), 13 (Hoosic River below Williamstown, 

Mass.), 14 (Hoosic River at North Petersburg), and 

42 (Wallkill River at Rosendale). The calculated 

average annual yields at these four sites exceed 

3,200 lb/mi2 for dissolved nitrate, 4,200 lb/mi2 for 

total nitrogen, and 450 lb/mi2 for total phosphorus 

(table 16). Sites 20 and 42 are more than 34 percent 

agricultural, and sites 13,14, and 42 have population 

densities exceeding 180/mi2

The lowest nutrient yields were in forested 

watersheds that are less than 5 percent agricultural sites 5,6, 7, and 32 (fig. 28) and the two 

watersheds on Schoharie Creek - sites 23 (mixed) 

and 25 (agricultural). The calculated average 

annual yields of dissolved nitrate at all six of these 

sites were less than 1,700 lb/mi2, and the yields for 

total nitrogen were generally less than 3,400 lb/mi2 . 

Total phosphorus yields for sites 5,6,7 and 32 were 

less than 150 lb/mi2, and those for sites 23 and 25 

were higher (396 and 231 lb/mi2, respectively). The 

average annual dissolved nitrate and total nitrogen 

yields for sites 23 and 25 were lower than expected 

(fig. 29A), possibly because these sites are 

downstream of Prattsville Reservoir, where much 

of the flow in Schoharie Creek is diverted to Esopus 

Creek; the low nutrient yields at these two sites 

could be due to water export and smaller discharge 

per basin area than at other sites.

Surface Water 57
76' 75° 74° 73°

44°

43'

42°

41'

Adirondack 

Mountains

f

1 / VERMONT

' I/I

EXPLANATION

 Basin boundary

-25

Sites with yield 

computed for 

1970-80

o

Sites with yields 

28 computed for

1970-80 and 1981-90

0 10 20 30 40 50 MILES

I |___II I I

I Tl I I 1

0 10 20 30 40 50 KILOMETERS

Base from U.S. Geological Survey digital data 1:2,000,000, 1972

Albers Equal-Area Conic projection

Standard parallels 29° 30' and 45° 30', central meridian -74°

Figure 28. Locations of surface-water sites for which nutrient yields in 1970-80 and 1981-90 were computed. 

(Site names are listed in table 5.)

58 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
CO 

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TOTAL NITROGEN .20

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TOTAL NITROGEN .20

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TOTAL PHOSPHORUS js

_

-

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" . 25 16 *28

32 .6, * . 45 

-. .7 -I

 |5 | , | , | , | , | ,

10 20 30 40 50

PERCENTAGE OF 

BASIN USED FOR AGRICULTURE

60

EXPLANATION

0 50 100 150 200 250 300 

1980 POPULATION DENSITY PER SQUARE MILE

 25 SAMPLING SITE AND NUMBER 

names are listed in table 5 and 

locations are shown in figure 28

Figure 29. Nutrient yield as a function of agricultural land use and population density in Hudson River basin watersheds.

Surface Water 59
The range of dissolved nitrate, total nitrogen, and 

dissolved ammonia yields indicates that dissolved 

nitrate and ammonia can account for half to threequarters of the total nitrogen load (right column in 

table 16). Total organic nitrogen yields, estimated as 

total nitrogen minus the inorganic component 

(dissolved nitrate and dissolved ammonium) range 

from 431 lb/mi2 at site 5 (Hudson River at Corinth) 

to 4,230 lb/mi2 at site 20 (Mohawk River at Fonda). 

The organic nitrogen yield represents 26 to 43 

percent of the total nitrogen yield at sites for which 

organic nitrogen yield was estimated; the total 

organic nitrogen component likely represents algae 

and other particulate organic matter. Although the 

high error of estimate associated with the dissolved 

ammonia yields (table 16) indicates that the actual 

organic nitrogen yield could be as much as 20 

percent higher or lower than these estimates, these

patterns indicate that organic nitrogen is an important part of the total nitrogen budget in the Hudson 

River basin. Published investigations of nitrogen 

cycling in the Hudson River basin, such as Murdoch 

and Stoddard (1992) and Howarth and others (1991), 

emphasized only dissolved nitrate, however, and 

might not accurately reflect total 

nitrogen yield.

Nutrient Inputs. Nutrient inputs were calculated for 

the 16 watersheds that contain sites for which nutrient 

yields were available, to relate nutrient yields to their 

principal sources in each watershed. The sources used 

in this analysis were fertilizer, manure, atmospheric 

deposition and treated waste-water. The calculated 

inputs do not represent the actual amounts of nutrients 

reaching the stream but, rather, the amount applied to 

each watershed. Not all of the amount applied to a

Table 16. Annual nutrient yields and standard errors of estimate at sites for which data are adequate for analysis, 1970-90. 

[Site locations shown in fig. 28. Yields are in thousands of pounds per square mile. Standard errors are in percent. Dash indicates no data.]

Constituent

Dissolved nitrate

Site 

Number

Annual Standard 

Yield Error

A. DATA BASED ON 1970-80

5

6

7

13

14

16

20

23

25

26

27a

28

32

42

43

45

1.03

1.42

1.42

3.24

3.28

1.78

4.05

.77

1.33

2.40

2.62

1.95

1.60

3.40

2.12

2.46

B. DATA BASED ON

20

28

32

3.39

2.24

1.89

6.23

6.40

6.63

19.80

7.91

4.85

7.30

28.80

14.60

6.42

6.49

4.11

13.30

21.70

13.00

6.56

1981-90

10.20

10.40

15.20

Total nitrogen

Annual 

Yield

SAMPLING

2.54

3.36

4.18

-

6.12

3.65

9.94

1.26

2.09

4.72

4.71

3.90

-

4.27

2.92

3.27

SAMPLING

5.42

4.42

3.75

Standard 

Error

6.98

5.94

4.59

-

8.03

3.74

9.40

32.60

11.90

4.39

4.60

4.20

-

16.50

10.80

7.41

21.80

6.58

28.90

Total phosphorus Dissolved ammonia

Annual 

Yield

0.0410

.138

.0901

1.20

.727

.195

.822

.396

.231

.284

.377

.240

.0813

.471

.386

.138

-

.199

.0901

Standard Annual Standard 

Error Yield Error

7.63 0.431 18.1

15.00

7.30 1.47 17.7

15.90

10.10

8.74

12.30 1.66 20.3

50.10

35.50

10.90

6.51 .869 14.8

9.62 .829 22.3

23.20

10.90

10.80

17.10

.

12.10 .439 13.4

43.30 .0958 33.4

Ratio of 

organic yield1 

to total 

nitrogen yield

0.416

-

.310

-

-

-

.426

-

-

-

.258

.289

-

-

-

-

-

.384

.470

1 Organic nitrogen calculated as total nitrogen yield minus dissolved nitrate yield minus total ammonia yield.

60 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
watershed reaches the stream because many processes 

can interfere. For example, nitrogen can be lost 

through the volatilization of ammonium in manure 

and fertilizer; also nitrogen and phosphorus can be 

lost through uptake by plants and through storage in 

organic debris or stream sediment. The proportion of 

nutrient input to the watershed that enters a stream is 

probably greater for treated wastewater than for other 

sources. Estimates of nutrient inputs from the several 

sources are useful in defining the relative importance 

of each source in a given watershed.

The largest annual inputs of nitrogen (exceeding 

12,800 lb/mi2) and phosphorus (exceeding 3,000 

lb/mi2) are in agricultural areas along the Mohawk 

River (sites 20, 26, 27A) and on the Wallkill River 

(site 42); about three-quarters of the nitrogen and 

phosphorus inputs in these areas are derived from 

fertilizer and manure (table 17; fig. 30). The input 

rates for nitrogen and phosphorus in the other two 

agricultural watersheds (sites 25 and 45, on Schoharie 

Creek and Wappinger Creek, respectively) are 

somewhat lower than those along the Mohawk River 

and Wallkill Rivers, but the predominant sources of 

nutrients at these sites are still derived from agricultural activities.

In contrast, forested watersheds in the upper 

Hudson River basin that drain the Adirondack 

Mountains-the Hudson River at Corinth (site 5), 

Hudson River at Glens Falls (site 6), and Hudson 

River at Fort Edward (site 7)-have the lowest nitrogen input rates (less than 3,200 lb/mi2) and 

phosphorus (less than 130 lb/mi2) of the 16 sites for 

which yields were calculated (table 17 and fig. 30). 

More than 90 percent of the nitrogen input to these 

watersheds are from the atmosphere. Although the 

watershed above site 32, a forested watershed in the 

Catskill Mountains, has a higher nitrogen-input rate 

(875 lb/mi2) than the Adirondack watersheds (sites 5, 

6, and 7), more than 95 percent of the nitrogen input 

to this watershed is also from atmospheric deposition 

(table 17). Estimates of phosphorus inputs indicate 

that, for these forested watersheds, the predominant 

source of phosphorus can be either agricultural areas 

or treated wastewater.

Nitrogen and phosphorus input rates for the two 

urban watersheds (Hoosic River sites 13 and 14) are 

more than 9,500 lb/mi2 and 210 lb/mi2 , respectively 

(fig. 30; table 17). Most of the nitrogen inputs in these 

watersheds are derived is from a combination of 

atmospheric and agricultural sources. The urban sites

are the only ones where more than 15 percent of the 

nitrogen inputs and 50 percent of the phosphorus 

inputs are derived from treated wastewater (fig. 30, 

table 17).

Watersheds above sites with mixed land use (sites 

16, 23, 28, and 43) have a wide range of nitrogen 

inputs (6,100 to 10,000 lb/mi2) and phosphorus inputs 

(about 1,000 to 2,640 lb/mi2) (fig. 30, table 17). The 

predominant source of nitrogen at all sites but 23 

(Schoharie Creek at Breakabeen) is agricultural activities; at site 23, the predominant source is atmospheric 

deposition (table 17). Atmospheric deposition is also 

an important source of nitrogen at site 16 (Hudson at 

Waterford) and site 28 (Hudson River at Green Island) 

- 42 and 27 percent of total nitrogen input, respectively (fig. 30). The predominant source of 

phosphorus input to these sites is agriculture; treated 

wastewater contributes less than 25 percent (fig. 30).

These results indicate that the nutrient inputs to the 

two largest nontidal tributaries to the Hudson River 

(sites 28, Hudson River at Green Island and 43, 

Rondout Creek at Eddyville) are largely derived from 

nonpoint agricultural sources. Although considerable 

error is likely in the estimates of nitrogen and 

phosphorus inputs, the high percentage of nitrogen 

derived from agriculture and atmospheric deposition 

(greater than 90 percent) indicate the importance of 

nonpoint sources of nutrients to large watersheds in 

the Hudson River basin. Patterns of nutrient input, by 

source for 1980-91, are similar to those for 1970-80 

(table 17).

Ratios of nitrogen yield to nitrogen input can 

indicate (1) the fate of nitrogen inputs, or (2) whether 

nitrogen-input estimates are accurate. Any comparison of yield with input rate for a given watershed 

should be qualified by the statistical errors associated 

with each. Despite the potential for error, some 

general patterns are evident from these ratios: (1) 

ratios of total-nitrogen yields to input rates greaterthan 0.8 are generally restricted to forested watersheds in the Upper Hudson River basin (sites 5,6, and 

7), and (2) ratios less than 0.3 are limited to the two 

sites on Schoharie Creek (site 23, mixed land use and 

site 25, agricultural). The high yield-to-input ratios at 

sites 5, 6, and 7 could indicate that input rates for 

these sites are underestimated-partly through underestimation of industrial discharges of nutrients into 

the Hudson River in the Glens Falls and Fort Edward 

vicinity, and partly through underestimation of nitrogen input from atmospheric deposition, because the

Surface Water 61
Table 17. Average annual nitrogen and phosphorus inputs, source of input, average annual yield, and ratio of 

yield to total input for sites in the Hudson River basin for which sufficient data are available for analysis.

[Input rates and yields are in thousands of pounds per square mile. Dashes indicate no value calculated. Site locations 

are shown in fig. 28]

Source of input, in percent

Site Average Yearly 

No. total input Fertilizer

Treated 

Manure wastewater

Atmospheric 

deposition

Average Annual 

Yield

Ratio of yield to 

total input

A. BASED ON 1970-80 DATA

Nitrogen

5

6

7

13

14

16

20

23

25

26

27A

28

32

42

43

45

Phosphorus

5

6

7

13

14

16

20

23

25

26

27

28

32

42

43

45

3.01

3.03

3.10

10.1

9.51

6.14

14.6

9.59

9.78

13.4

13.5

9.27

8.90

12.9

10.0

8.26

0.0615

0.0746

0.122

2.30

2.17

0.994

3.67

1.18

1.74

3.18

3.34

2.00

0.137

3.50

2.64

2.09

2.20

2.23

2.25

19.2

19.8

19.1

23.3

12.4

20.3

23.1

22.3

21.1

0.516

35.8

33.9

36.6

45.2

38.1

24.0

26.5

28.2

48.7

38.7

42.4

47.7

40.9

37.6

40.7

14.1

53.0

52.3

60.6

4.07

4.12

4.13

20.7

24.0

35.6

52.5

30.3

46.5

51.9

49.3

44.0

0.412

48.0

45.7

51.1

34.9

29.4

18.4

16.4

18.8

36.3

33.0

42.3

44.7

35.2

32.0

33.1

6.48

33.1

34.1

35.8

0.553

1.09

3.09

17.8

16.5

3.30

9.70

2.56

1.85

7.73

10.3

7.70

1.67

5.15

4.87

1.24

19.9

32.5

57.6

57.1

53.0

15.0

28.3

15.3

7.66

24.0

30.5

26.2

79.5

13.9

13.6

3.60

93.2

92.6

90.5

42.4

39.7

42.0

14.6

54.8

31.4

17.3

18.2

27.2

97.4

11.1

15.5

11.1

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

2.54

3.37

4.18

-

6.12

3.65

9.94

1.26

2.09

4.72

4.71

3.90

-

4.27

2.92

3.28

0.0410

0.138

0.0901

1.120

0.727

0.195

0.822

0.396

0.231

0.284

0.377

0.240

0.0813

0.471

0.386

0.138

0.844

1.11

1.35

-

0.643

0.595

0.681

0.132

0.214

0.352

0.350

0.421

-

0.332

0.291

0.397

0.666

1.85

0.738

0.521

0.334

0.196

0.224

0.336

0.133

0.089

0.113

0.120

0.592

0.135

0.146

0.0660

B. BASED ON 1981-90 DATA

Nitrogen

20

28

32

Phosphorus

28

32

14.6

9.26

8.90

1.977

0.136

27.7

25.3

0.576

43.44

13.90

47.8

39.6

0.368

30.02

5.995

9.94

7.90

1.71

26.54

80.10

14.6

27.2

97.4

-

-

5.42

4.42

3.75

0.1988

0.0901

0.372

0.477

0.421

0.101

0.662

62 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
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CORINTH (Site 5)

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: n

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C..O

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-

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MOHAWK RIVER -

AT FONDA -

(Site 20) -:

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n

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HUDSON RIVER AT

WATERFORD (Site 16)

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EXPLANATION

INPUTS

1. Agriculture

2. Sewage

3. Atmospheric deposition

YIELD

4. Dissolved nitrate

5. Total nitrogen

2.8 

2.4 

2.0 

1.6 

1.2 

0.8 

0.4 

0

HUDSON RIVER AT 

WATERFORD (Site 16)

EXPLANATION

INPUTS

1. Agriculture

2. Sewage

YIELD 

3. Total Phosphorus

Figure 30. Annual nutrient inputs and yield at five sites in the Hudson River basin, N.Y., as calculated from samples collected 

during 1970-80. A. Nitrogen. B. Total phosphoorus.

Surface Water 63
ratio for the uppermost site (site 5, Hudson River at 

Corinth, above Glens Falls and Fort Edward) also is 

high. The high yield-to-input ratios at these forested 

sites could also be due to the failure of the forest 

ecosystem in these watersheds to retain atmospherically deposited nitrogen-a phenomenon known as 

nitrogen saturation (Murdoch and Stoddard, 1992). 

Nitrogen saturation is avoided in other watersheds, 

particularly those dominated by agriculture, by the 

removal of nitrogen through the harvest of plant or 

animal matter. The rate of plant or animal harvest at 

these three forested sites is presumably much less 

than at the other sites, thus, nitrogen saturation is 

possible.

Most of the forested sites have a high ratio of 

phosphorus yield to input (greater than 0.55). This 

could indicate underestimation of phosphorus-input 

rates; one reason could be the omission of input from 

geologic sources.

The two sites with the lowest ratios of nitrogen 

yield to input (less than 0.22) were on Schoharie 

Creek sites (sites 23 and 25) (table 17). The low 

ratios could be due to the export of water from the 

upper 215 mi2 (35 percent) of the watershed, which 

significantly decreases the flow at sites 23 and site 

25. For example, the mean annual flow at Schoharie 

Creek at Prattsville above the diversion at the 

Schoharie Reservoir for 1950-92 was 1.98 

(ft3/s)/mi2, whereas the flow of Schoharie Creek at 

Burtonsville, below the diversion, is only 1.19 

(ft3/s)/mi2, or 40 percent less than at Prattsville. 

Because the transport of nutrients is controlled to a 

large degree by discharge, the low nitrate and total 

nitrogen yields and low ratio of yield to input for 

sites 23 and 25 could be attributable to the diversion 

of water. The decreased discharge could also result 

in greater storage of nutrients in the flood plain of 

Schoharie Creek and increased uptake by plants. The 

ratios of phosphorus yield to input for the two 

Schoharie Creek sites are below 0.4, which is not 

significantly lower than that for other sites.

Although the nitrogen yields for the two Schoharie 

Creek sites (23 and 25) seem consistent with the 

population densities of this watershed, the low ratio 

of yield to input indicates that the correlation between 

population density and yield may be weaker than 

indicated by the scatterplot in figure 29. Because 

agricultural activities are the major sources of nutrient inputs to streams in the Hudson River basin, the 

close relation between population density and nutrient yields indicated by these plots could be spurious.

Many of the sites lie along the mainstem of the 

Hudson River (sites 5, 6,7, 16 and 28); thus, the 

apparent correlation between nutrient yield and 

population density could largely reflect conditions 

along the mainstem, not the smaller tributaries.

Mass Balance. Mass-balance calculations were done 

for nine sites as a check of nutrient yields; results 

indicate that much of the mass of nutrients transported from the combined drainages of the upper 

Hudson and Mohawk River subbasins (represented at 

site 28, Hudson River at Green Island) is derived 

from the upper 2,100 mi2 drainage of the Mohawk 

River basin (site 20). The mass balances are based on 

yields calculated for 1977- 81, the only 5-year period 

before 1982 with yield data available for the outlet of 

the Upper Hudson River basin (Hudson River at 

Waterford, site 16). Mean annual flows for this period 

at all sites were equal to or greater than mean annual 

flows for the 30-year period 1960-89; therefore, the 

yields for 1977-81 also are probably somewhat higher 

than average.

The sum of the mass of nutrients transported past 

the Mohawk River subbasin outlet (site 27A, Mohawk 

River at Crescent Dam) and the upper Hudson subbasin outlet (site 16, Hudson River at Waterford) is 

approximately equal to the total mass transported past 

site 28 (Hudson River at Green Island), just downstream from these sites. The mass of dissolved nitrate 

(17.2 million Ib), total nitrogen (33.8 million Ib), and 

total phosphorus (2.17 million Ib) transported past 

sites 27A and site 16 during 1977-1981 is 5.5 percent, 

3.7 percent, and 6.8 percent higher, respectively, than 

was transported past site 28 (table 18). These differences are similar to the standard error of estimate for 

the yields (table 16), indicating that the yields calculated for sites 16 and 27A are consistent with those 

calculated for site 28. In contrast, the average mass of 

nutrients transported past site 20 (Mohawk River at 

Fonda) during 1977-81 is significantly greater than 

was transported past site 26 (Mohawk River at Tribes 

Hill), 5 mi downstream. Site 26 is 0.3 mi downstream 

from Schoharie Creek; hence, the combined masses 

transported past site 20 and site 25 (Schoharie Creek 

at Burtonsville) should approximate the masses transported past site 26. However, the masses of dissolved 

nitrate (9.5 million Ib), total nitrogen (21.8 million Ib) 

and total phosphorus (1.94 million Ib) calculated for 

site 20 are 21, 38, and 85 percent higher than the 

masses calculated for site 26 (7.85 million Ib, 15.7 

million Ib, and 1.05 million Ib, respectively). These

64 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
differences are more than twice the standard error 

estimates (table 16); hence, either some storage or 

uptake of nutrients occurs in the 5-mi reach between 

Fonda and Tribes Hill, or the nutrient masses calculated for site 20 are overestimated.

Dissolved nitrate and total nitrogen yields for site 

20 during 1981-90 are 16 percent and 45 percent less 

than those for 1970-80 (table 16); these differences 

exceed the standard error for 1981-90, suggesting 

that yields for 1970-80 are overestimated. One 

possible reason for the overestimate could be that the 

water samples collected at site 20 during 1970-80 

were collected from a dock on the northern side of 

the Mohawk River, 0.2 mi downstream and on the 

same side as the mouth of Cayadutta Creek. From 

1970-80 Cayadutta Creek had elevated nutrient 

concentrations caused by discharge of incompletely 

treated wastewater from sewage-treatment facilities 

(Bode and others, 1992). Thus, the elevated rates of 

nutrient transport past site 20 could reflect incomplete mixing of the two waters and a disproportionate amount of water from Cayadutta Creek. The 

1981-90 samples probably are more representative 

of conditions in the Mohawk River because they 

were collected by multivertical sampling at a bridge 

0.2 mi downstream from the previously used dock. 

Therefore, a corrected estimate of nutrient transport 

past site 20 was computed as the mass transported 

past site 25 minus the mass transported past site 26 

(table 18).

Most of the nutrient mass transported past the 

outlet of the combined Upper Hudson and Mohawk 

River subbasins (site 28) are derived from the 

Mohawk subbasin. The mass of dissolved nitrate, 

total nitrogen, and total phosphorus transported at 

site 27A (Mohawk River at Crescent Dam) represents 58.3 percent, 50.9 percent, and 66 percent of 

the mass transported past site 28, even though the 

drainage area upstream from site 27A represents 

only 42 percent of the drainage area upstream from 

site 28.

Nutrient yields calculated for site 20 (the Mohawk 

River at Fonda, an agricultural watershed) represent a 

disproportionate amount of nutrients within the 

Mohawk River drainage. Although the drainage area 

upstream of this site represents only 26 percent of the 

drainage area upstream from site 28, the mass of 

dissolved nitrate (6.26 million Ib), total nitrogen 

(13.3 million Ib), and total phosphorus (0.728 million 

Ib) transported past site 20 is 38 percent, 41 percent,

and 36 percent of the corresponding masses transported past Green Island (site 28, table 18). The high 

nutrient-transport rates calculated for site 20 are most 

likely due to the high input rates of nitrogen and 

phosphorus in this watershed; 40 percent of the total 

nitrogen and 48 percent of the total phosphorus inputs 

in the watershed upstream from site 28 originated 

within the Mohawk River watershed above Fonda 

(site 20). These results are further evidence that 

agricultural sources contribute the bulk of nitrogen 

and phosphorus inputs to streams of the Hudson 

River basin.

Table 18. Average mass of nutrients transported at selected 

sites in the Upper Hudson and Mohawk River subbasins, 

1977-80.

[Mass in millions of pounds. Numbers in parentheses are standard 

error of estimate, in percent. Discharges are in cubic feet per 

second. Dash indicates no data available. Site locations are shown 

in fig. 28. Mass value based on yields for samples collected during 

1970-80].

Constituent mass

Dis- Total

Site solved Total phosno. nitrate nitrogen phorus

Drainage

area 

(square

miles)

Mean annual 

discharge

1960-89 1977-81

Upper Hudson Subbasin

16

2.93 

(6.78)

7.61 

(4.85)

6.86

(7.02)

17.2

(3.77)

Mohawk Subbasin

20 9.50 21.8 

(9.91) (10.7)

20* 6.26 13.3

25

0.113 

(7.89) 

0.818 

(8.81)

1.94 

(16.1)

0.728

1.59 2.37 0.322

(16.4) (13.4) (48.3)

26 7.85 15.7 1.05

(7.77) (5.42) (15.5)

27a 9.50 16.6 1.35

(7.74) (5.31) (7.50)

Upper Hudson-Mohawk Outlet

28 16.3 32.6 2.03

(4.12) (4.23) (9.63)

Lower Hudson Subbasin

43 2.54 3.28 0.483

(14.5) (12.4) (13.3)

45 0.478 0.622 0.0234

(7.19) (7.78) (15.3)

2,755

4,620

2,118

2,118

886

3,090

5,050 5,290

8,113

4,570 4,730

4,570 4,730

1,060 1,270

3,438 5,720 5,906

8,090 13,600 14,500

1,150 1,610 1,690

181 264 264

*Estimate for site 20 based on mass at site 26 minus mass at site 25

Surface Water 65
Suspended Sediment

Nutrients, organic compounds (including pesticides), and metals can sorb to suspended sediment 

and, therefore, can affect the transport of a wide 

variety of constituents. Suspended-sediment concentration and yields in the Hudson River basin are 

related to land use.

Concentration

The relation between suspended-sediment concentration and discharge varies spatially . For example, 

the sediment concentration-to-discharge relations for 

site 12 (Hudson River at Still water, a site typical of 

conditions in the Upper Hudson River basin) and 

from site 27B (Mohawk River at Cohoes) (fig. 31) 

show considerable scatter, but sediment concentra1,000

O tr 100 

P ai

o

O -j 

O ^

10

HUDSON RIVER AT STILLWATER (Site 12)

0.1 10 100

10,000

1,000

O tr P ai

o

o H 

o ^

100

10

MOHAWK RIVER AT COHOES 

(Site 27b)

1 10 100

DISCHARGE, 

IN THOUSANDS OF CUBIC FEET PER SECOND

Figure 31. Suspended-sediment concentration as a 

function of discharge for Hudson River at Stillwater, N.Y., 

and Mohawk River at Cohoes, N.Y., 1970-90. (Locations are 

shown in fig. 12).

tion generally increases with discharge. Sediment 

concentrations at main-stem Hudson River sites are 

usually less than 10 mg/L when discharge is less than 

10,000 ft3/s but generally increase at an increasing 

rate to 50 mg/L at discharges of more than 35,000 

ft3/s (fig. 31). Sediment concentrations at site 27B 

(Mohawk River at Cohoes), by contrast, are generally 6 to 25 mg/L at discharges less than 10,000 ft3/s 

but typically increase to more than 150 mg/L at 

discharges of 35,000 ft3/s (fig. 31).

The lowest median suspended-sediment concentrations are at sites representing forested watersheds. 

For example, site 32 (Esopus Creek at Shandaken, in 

the Catskill Mountains) has the lowest median 

suspended sediment concentration (3.0 mg/L) of the 

eight sites with suspended-sediment data (fig. 32); it 

also represents the most heavily forested watershed 

of the eight sites (98 percent of the drainage area). In 

contrast, site 27B (Mohawk River at Cohoes) has the 

highest median suspended-sediment concentration 

(26 mg/L) of the eight sites, and its watershed is the 

least forested (55 percent of the drainage area). 

Median suspended-sediment concentrations for sites 

in the Upper Hudson River basin (sites 6, 7, 9, 12, 

and 16) range from 4 to 7.5 mg/L (fig. 32). Forest 

cover at these sites ranges from more than 90 percent 

of the drainage area upstream from site 6 to less than 

80 percent of the drainage area upstream from site 

16. The median suspended-sediment concentration 

at site 28 (Hudson River at Green Island, 67 percent 

forest cover, 11 mg/L) is between the median 

suspended-sediment concentration for each of the 

two sites that lie just upstream (sites 16 and 27B). 

These results indicate that suspended-sediment 

concentrations in the Hudson River basin are 

inversely proportional to percent forest cover. The 

effect of urbanization on suspended-sediment 

concentrations cannot be assessed, however, 

because no data are available from sites in urban 

watersheds.

Yields

Sediment transport in the Hudson River basin is 

highly variable over time and space, and the sparsity 

of data from all sites except those in the Upper 

Hudson River subbasin makes estimation of sediment 

yields difficult. The sparsity of data also is a major 

hindrance to interpretation of suspended-sediment 

transport because most of the annual sediment load 

for a site can be transported in just a few days and,

66 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
1,000

O ft 1 00

^ CL

(3

o d 

o ^

10

 A B BCD D C D E F

[

, 1 1

I JL c. c li pi -J--J m

- 3| J

T 1

4

1 7- 5

1

i 1 26

1 ll

j

._

f Ijl T 1 :

T !

i iii

32 6 7 9 12 16 28 27b

SITE NUMBER 

EXPLANATION

Percentile 

90

Median 

Concentration

2.0

75

50

25

10

A AB C

Differing letters indicate 

significant difference in 

median concentration, 

according to KruskalWallis test

Figure 32. Range of suspended-sediment concentrations at 

sites in the Hudson River basin for which 1970-90 sediment 

data are available. (Site locations are shown in fig. 12.)

therefore, could easily be overlooked. For example, 

in an average year, about half of the total annual 

sediment load at site 16 (Hudson River at Waterford, 

a daily-values sediment station) is transported in the

18 days with the highest discharges. Hence, the 

accuracy of yield estimates depends on the number 

and availability of samples collected during high 

flows, and the suspended-sediment yields calculated 

for the two daily-values sites (sites 12 and 16, 

Hudson River at Stillwater and at Waterford) are 

generally more reliable than those calculated for 

other sites.

As mentioned previously, two types of yield are 

discussed in this report: (1) an average of the 

sediment yield for 3 years-a year in which the annual 

mean flow was ranked in the upper 10 percent of the 

annual mean flows, a year in which the annual mean 

flow was equal to the mean annual flow, and a year in 

which the annual mean flow was ranked in the lower 

10 percent of the annual mean flows (table 19); and 

(2) sediment yield for 1978. Estimates of sedimenttransport rates for each site are based on analyses of 

more than 90 samples and include samples collected 

during a discharge that was exceeded less than 1 

percent of the time (table 19). Of the 156 suspendedsediment samples collected at site 27B (Mohawk 

River at Cohoes), nearly all were collected in 1976; 

hence, the calculated sediment yields for this site 

largely reflect conditions during 1976. For sites 12 

and 16 (the sites with daily sediment data), daily 

suspended sediment data were missing for only 15 

and 7.2 percent of the days, respectively, of the 3 

years used to calculate the average transport rate. No 

days had missing values for 1978.

The standard error for computed yields ranges from 

11 to 30 percent. Most of the errors are between 15 

and 30 percent (table 20). The largest error is for site 

32, Esopus Creek at Shandaken; this may reflect the 

variable concentration-to-discharge relation for this 

small watershed. Comparison of sediment transport

Table 19. Discharge characteristics represented by samples used to calculate suspended-sediment yields in 

Hudson River basin.

[Site locations shown in fig. 12.]

Site 

no.

6

7

27B

28

32

No. 

samples 

used for 

estimate

90

423

156

96

168

No. high-flow samples 

(taken at a discharge 

exceeded 1 0 percent 

of time or less)

23

126

65

15

17

Percent of time discharge was 

exceeded for sample with:

Highest 

dischage

0.05

0.03

0.01

0.60

0.06

Lowest 

discharge

95

98

92

96

99

Years of 

sample 

collection

1975-79

1975-83

1976-79

1970-90

1980-90

Years of flow data used 

for 3- year average yield 

estimate*

1978, 1981, 1983

1978, 1981, 1983

1978, 1981, 1983

1978, 1981, 1983

1972, 1971, 1928

*Years of flow data used represent discharge from years with high, medium, and low mean annual flows.

Suspended Sediment 67
Table 20. Suspended-sediment yield calculated for sites in the Hudson River basin.

[Yields are in tons per day per square mile. SE (standard error of estimate) in percent. A dash indicates missing data. Site 

locations are shown in fig. 12. Asterisk denotes sites with daily values. Average yield is based on 3 years.]

Site 

no.

6

7

12*

16*

27B

28

32

Site name

Hudson River at Glens Falls

Hudson River at Fort Edward

Hudson River at Stillwater

Hudson River at Waterford

Mohawk River at Cohoes

Hudson River at Green Island

Esopus Creek at Shandaken

Predominant 

land use in 

watershed

Forest

Forest

Forest

Mixed

Agricultural

Mixed

Forest

Average Yield estimate

Yield

0.053

.044

.066

.097

.25

.22

.076

SE

22

12

-

-

11

21

30

1 978 Estimate

Yield

0.078

.058

.080

.13

.36

.28

-

SE

14

9.5

-

-

9.3

28

-

rates among sites 27B (Mohawk River at Cohoes), site 

16 (Hudson River at Waterford), and site 28 (Hudson 

at Green Island), suggests that, the estimates of 

sediment transport at these sites are reasonably consistent. For example, the 1978 value for site 28, 

estimated as the sum of 1978 values for sites 16 and 

27B, is 1,820 (ton/d)/mi2-about 17 percent lower than 

the 2,240 ton/yr estimated from 1978 site 28 data 

alone. The 3-year average sediment yield calculated 

for site 28 from site 16 and site 27B data combined 

(1,330 (ton/d)/mi2) is 26 percent lower than the 3-year 

estimate made from site 28 data alone. Thus, the 

estimates based on the sum of sediment transported at 

sites 16 and 27B are within a standard error of 

estimate for both the 3-year and 1978 periods.

Sediment yield is related to watershed land use 

and drainage area. The relations between sediment 

yield and land use are similar to those for sediment 

concentration; for example, annual sediment yield 

generally decreases with increasing forest cover for 

both the 3-year averages and the 1978 estimates 

(table 20, fig. 33). The one exception is the 

somewhat higher average sediment yield for site 32 

(Esopus Creek at Shandaken) than for Upper Hudson 

basin sites with similar forest cover (sites 6 and 7); 

this may be attributable to the small size of the 

watershed represented by site 32 (less than 7 percent 

of the drainage area of sites 6 and 7) because, in 

general, sediment yield also decreases with increasing watershed drainage area (Ritter, 1978). 

Watershed land use in the Upper Hudson subbasin 

has a greater effect than drainage area on sediment 

yield. For example, the drainage area of the Hudson 

River from Glens Falls (site 6, about 2,800 mi2) to 

Green Island (site 28, about 8,000 mi2) increases 

nearly threefold, and the sediment yield increases 

over fourfold, from 0.053 (ton/d)/mi2 to

0.22(ton/d)/mi2 . This can probably be attributed to 

the decrease in the proportion of forest cover from 

the watershed above site 6 downstream to the watershed above site 28.

A comparison of sediment-transport rates indicates 

that most of the sediment transported at site 28 

(Hudson River at Green Island) originates in the 

Mohawk River basin rather than in the Upper Hudson

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 Average for 1978,1981, 

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Figure 33. Relation of suspended-sediment yield, 1970- 

90, to percentage of watershed in the Hudson River basin 

that is forested. (Site locations are shown in fig. 12.)

68 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
basin, even though the Mohawk River basin constitutes about 40 percent of the combined drainage area. 

The mass of sediment transported past site 27B constitutes 66 percent of the summed mass of sites 27B and 

16 (Hudson River at Waterford) as calculated from the 

3-year average, and 68 percent of the summed yield of 

these sites as calculated from the 1978 data. Thus, the 

Mohawk River basin contributes a disproportionate 

amount of the sediment in the combined Upper 

Hudson and Mohawk River subbasin drainages, 

presumably because it contains considerably more 

agricultural land than the heavily forested Upper 

Hudson basin.

The sparsity of sediment data for Mohawk River 

sites 20 and 25, upstream from Cohoes, makes further 

assessment of suspended-sediment yield in the 

Mohawk River basin impossible, and the sparsity of 

sediment data from sites downstream of the Hudson 

River at Green Island makes estimation of sediment 

yield in the Lower Hudson subbasin difficult.

Pesticides

Local variability in pesticide-application rates, as 

indicated by reported patterns of DOT, chlordane, 

and 2,4-D use, suggest that rates of pesticide detection and median pesticide concentrations in watercolumn and streambed sediments also should vary 

locally. Because half of the sites from which pesticide 

data are available are in urbanized watersheds, most 

of the discussion of pesticide-detection rates and 

concentrations in this report pertain to comparisons 

of urban watersheds with nonurban watersheds. 

Because the data presented here were collected 

largely in the late 1970's, the following interpretations may not reflect current (1996) conditions and 

indicate only general relations between pesticide 

concentrations and land use. Data on all pesticides 

but 2,4-D are from streambed-sediment samples; 

2,4-D data are from water-column samples.

The bed-sediment data do not indicate that the 

patterns of DDT detection and median DDT concentrations differ among the land-use categories. Total 

DDT was detected in streambed sediment in concentrations above 0.1 fig/kg in all but 1 of the 21 

watersheds (fig. 34A); thus, a chi-square analysis 

indicated no significant difference in percent detection between urban and nonurban watersheds. 

Similarly, a Mann-Whitney analysis of variance on 

ranks confirmed that the median streambed-sediment 

concentrations for urban sites (5.8 ^ig/kg) was not

significantly higher than the median concentration for 

nonurban sites, (3.0 |ig/kg) (fig. 34B). Total DDT 

concentrations exceeding 50 ^ig/kg were detected in 

one urban watershed (site 52, Sawmill River at 

Yonkers) and in one agricultural watershed (site 27A, 

Mohawk River at Crescent Dam).

Unlike DDT, chlordane was detected more 

frequently at urban-watershed sites than elsewhere, 

and median chlordane concentrations for urban-watershed sites exceed those for nonurban-watershed sites. 

Chlordane concentrations in more than 80 percent of 

the samples from urban sites exceeded the detection 

limit of 2 ^ig/kg (fig. 34A); concentrations at fewer 

than 20 percent of the nonurban sites exceeded the 

detection limit. A chi-square statistical analysis 

confirms that these differences in detection between 

urban and nonurban watersheds is statistically significant at the 0.05 level. A Mann-Whitney analysis of 

variance on ranks confirmed that the median 

streambed-sediment concentration for urban watersheds, 5.0 ^ig/kg, is also significantly higher (at the 

0.05 level) than the median concentration for nonurban watersheds, less than 2 ^ig/kg (fig. 34B). The 

highest chlordane concentration in streambed 

sediment, greater than 90 ^ig/kg, was in a highly 

urbanized watershed (site 52, Sawmill River at 

Yonkers, N.Y.). Aldrin was not detected in any 

streambed-sediment samples.

The small number of sites with 2,4-D data (11 

sites) makes a relation between 2,4-D detection and 

land use difficult to confirm. 2,4-D was detected in 

about half the water-column samples from sites in all 

land use-categories (fig. 34A), but no statistical 

comparison of median 2,4-D concentrations could be 

made between urban and nonurban watersheds 

because only two samples from urban watersheds 

were available. The highest 2,4-D concentration, 0.04 

(ig/L, was in a sample from site 44 (Twaalfskill 

Creek), in an agricultural watershed (fig. 34B).

The spatial distribution of pesticide detections and 

concentrations indicates that pesticide concentrations 

are partly related to land use. Some general conclusions can be given about total DDT and chlordane 

that are based on differences in detection rates and 

concentrations according to land use. For example, 

DDT was detected in nearly all streambed-sediment 

samples, including those from nonurban watersheds, 

and the median DDT concentration did not differ 

significantly between urban and nonurban sites (fig. 

34). The widespread occurrence of DDT reflects the

Suspended Sediment 69
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application of DDT in urban, forested, and agricultural areas as reported by Rod (1989). Chlordane, by 

contrast, was detected much more frequently in urban 

watersheds than nonurban watersheds (fig. 34), and 

the median concentrations for urban watersheds were 

significantly greater than the median concentration 

for nonurban watersheds. The pattern of chlordane 

detection parallels the pattern of chlordane use, as 

chlordane was applied mainly in urban settings.

Rod (1989) concluded that breakdown products of 

DDT would be detected in Hudson River sediments 

longer than chlordane. Rod's estimates are based 

largely on detailed analyses of three cores collected in 

the tidal sections of the Hudson River by Bopp and 

others (1982), who collected p,p'-DDD samples at 

depth intervals ranging from 1 to 4 cm (2.5 to 10 in.) 

from three sites along the tidal reaches of the Hudson 

River, and chlordane samples at intervals from 5 to 7 

cm (13 to 18 in.) at one site near New York City. Bopp 

and others (1982) also found that p,p'-DDD constituted about 80 percent of total DDT in these cores; 

hence, p,p'-DDD concentrations should be similar to 

total DDT concentrations. Ages of core sections were 

determined from radionuclide-activity tests; the 

relation between p,p'-DDD concentration and age 

differs among the three cores. For example, the 

concentration of p,p' DDD peaked first at site C (near 

Newburgh) around 1960, and subsequently peaked at 

site E (near Manhattan Island) in the early 1960s (fig. 

35). Concentrations of p,p'-DDD at site B (near 

Kingston) remained fairly constant from around 1960 

to the mid-1970s. Rod attributed the large decrease in 

p,p'-DDD concentrations at site E after 1963 to 

increased sediment transport and accelerated DDT 

degradation in urban settings in the southern part of the 

Hudson River basin and concluded from these patterns 

that, although DDT use was banned in 1972, detectable 

concentrations of DDD would persist in agricultural 

and forested watersheds in the Hudson River basin 

well into the 1990s.

The distribution of chlordane concentrations with 

depth in Hudson River sediments indicates that chlordane is less persistent than DDD and that chlordane 

concentrations declined even before chlordane use 

was phased out in the early 1980s (Rod, 1989). 

Concentrations of chlordane in core E from the lower 

Hudson River (near Manhattan Island, N.Y.) peaked 

in the 1960s and early 1970s (fig. 36) and declined 

substantially thereafter (Bopp and others, 1982). Rod 

(1989) concluded that, at this rate of decline, chlordane concentrations in bed sediments in tidal sections

of the Hudson River should be below 20 u.g/kg by the 

early 1990s.

In general, few data on such commonly used pesticides as atrazine and alachlor are available; hence, the 

relation between pesticide concentrations and land use 

across the Hudson River basin cannot be assessed.

Despite the lack of data on all but a few pesticides in 

Hudson River basin streams, the trends for two persistent compounds-DDT and chlordane-in streambed 

sediments indicate that pesticide detection and concentration correlate with land use and past patterns of 

pesticide use. As DDT and chlordane degrade with 

time, the relation between the concentrations of these 

compounds and land use will presumably become 

obscure.

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Manhattan Island by Bopp and others (1982). (Modified from 

Rod, 1989, fig. 8-4).

Suspended Sediment 71
SUMMARY AND CONCLUSIONS

The purpose of this study was to (1) compile, 

screen, and analyze the available water-quality data 

on nutrients (nitrogen species and phosphorus), 

suspended sediment, pesticides, and volatile organic 

compounds in the Hudson River basin (which covers 

more than 13,400 mi2 and encompasses parts of 

eastern New York, Vermont, New Jersey, Massachusetts, and Connecticut), and relate these data to 

pertinent hydrologic factors and land use in the 

Hudson River basin, and (2) interpret these data to 

provide a general description of surface-water and 

ground-water quality conditions in the basin and 

indicate information gaps.

The predominant land use in the basin is forest (62 

percent); 25 percent of the land is categorized as 

agricultural, and 7.8 percent as urban or residential. 

Most of the urban and agricultural areas are in valley 

lowlands and areas within 20 mi of large rivers in the 

western and central parts of the basin.

Ground water

Ground-water-sampling sites are characterized in 

this report by (1) aquifer type-either unconsolidated 

material that consists of bedrock or glacially derived 

sediments, and (2) the predominant land use within a 

0.5-mi radius of each site. Land use at each well is 

classified as urban, agricultural, or forest.

Nutrient-data analysis are limited to nitrate concentrations, many of which lack supporting well-depth 

and aquifer-material information. Only 100 wells in 

the study area that have records of nitrate concentrations for the period of interest (1970-90) also have 

information have well-depth and aquifer material; 63 

of these wells tap unconsolidated aquifers, and 37 tap 

bedrock aquifers. Most of these data were collected 

during 1979 and 1986-1988. All nutrient data were 

collected by the U.S. Geological Survey.

Nitrate concentrations in water from unconsolidated deposits range from less than 0.1 mg/L (the 

analytical detection limit) to 16 mg/L, with a median 

concentration of 0.23 mg/L, and the concentrations in 

water from bedrock aquifers range from less than 0.1 

to 11 mg/L, with a median concentration of 0.3 mg/L. 

Nitrate concentrations in water samples from unconsolidated aquifers do not differ significantly from 

those in samples from bedrock aquifers. Although 

nitrate concentrations appear to decrease with well 

depth in unconsolidated aquifers and bedrock

aquifers, those decreases were significant only in 

unconsolidated aquifers. No statistically significant 

difference in nitrate concentrations in unconsolidated 

aquifers or bedrock aquifers could be identified 

among differing land-use categories.

Only 11 ground-water-sampling sites in the 

Hudson River basin have pesticide or volatileorganic-compound data for the period of interest 

(1970-90). Water from only one of these sites, in 

Schenectady County, N.Y., contained a compound 

(diazinon) in concentrations greater than the detection limit 0.02 |Llg/L.

These results suggest that the ground-waterquality data for the Hudson River basin that are available in NWIS are not adequate to assess current 

nutrient and pesticide concentrations in the Hudson 

River basin and their relation to land use.

Surface water

Each surface-water site represented in this report 

was assigned to one of four land-use categories, 

depending on the predominant land use in the drainage basin above the site. Watersheds that are more 

than 25 percent agricultural and less than 11.5 percent 

urban were termed agricultural, and watersheds that 

are more than 8 percent urban and less than 20 

percent agricultural were termed urban. Watersheds 

that are more than 78 percent forested and less than 

18 percent agricultural were classified as forest. Sites 

not included in any of these three categories were 

classified as mixed.

Most of the nutrient data were collected during 

1970-80. Data for 1981-90 are limited, and only two 

sites have more than 30 samples for that period. In 

general, the data represent an even distribution of 

flow conditions, season, and land use. Of the 19 sites 

with nutrient data and daily discharge data for 1970- 

80, only two are more than 9.5 percent urban; thus, 

the data for urban sites are extremely sparse.

Suspended-sediment data are available for eight 

sites; because these data were collected during 1970- 

80, assessment of current conditions at many of the 

sites is not possible. Six of the sites are on the upper 

Hudson River, above the Mohawk River outlet, one is 

at the outlet of the Mohawk River, and one is in a 

small forested watershed in the Catskill Mountains. 

Assessment of suspended-sediment concentrations 

and yields is limited because of the sparsity of data 

for agricultural watersheds, and lack of data for urban 

watersheds.

72 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
Pesticide data also are insufficient for a basinwide 

assessment of current conditions in either the water 

column or bed sediment. Bed-sediment concentrations of five compounds (DDE, DDD, DDT, 

chlordane, and aldrin) are available at about 20 sites, 

half of which represent urban watersheds. Most of the 

streambed-sediment samples were collected before 

1980 and, therefore, do not necessarily reflect current 

conditions. The only pesticide for which watercolumn data are available is 2,4-D; these data were 

collected at 11 sites. Because only one sample was 

collected from each site, data cannot be used to establish the relation between 2,4-D concentration and 

discharge. Virtually no information on concentrations 

of other commonly used pesticides in the Hudson 

River basin, such as atrazine and alachlor, is 

available.

Concentrations of nutrients in surface waters in the 

Hudson River basin can be related to agricultural and 

urban activities. In most farmed watersheds, 

dissolved nitrate, total nitrogen, and total phosphorus 

concentrations are directly related to stream 

discharge, indicating a predominance of nonpoint 

sources in these regions. In contrast, the concentrations of these constituents in farmed watersheds that 

are more than 5 percent urban and that have a population density exceeding 200 per mi2 do not increase 

with increasing discharge, indicating a mix of point 

and nonpoint sources. Concentrations of these 

constituents in two urban watersheds are inversely 

related to discharge, suggesting a predominance of 

point sources in urban areas.

Dissolved nitrate and total nitrogen concentrations 

at sites draining both small and large forested watersheds are directly related to discharge, suggesting 

that nitrogen from nonpoint sources predominates in 

waters of forested watersheds. Total phosphorus 

concentrations are not strongly related to discharge at 

forested sites, and the total-phosphorus concentrations at many forested-watershed sites were below 

the detection limit of 0.01 mg/L; hence, the predominant control on phosphorus concentrations is 

unknown.

The sparsity of long-term nutrient data in the 

Hudson River Basin limits analysis of temporal 

trends in nutrient concentrations to a few sites. Longterm records for two forested watersheds in the 

Catskill Mountains indicate that dissolved nitrate 

concentrations increased four- to five-fold during 

1970-90.

Agricultural and urban watersheds generally have 

higher median concentrations of dissolved nitrate, 

dissolved ammonium, total nitrogen, and total 

phosphorus than watersheds in the forested or mixedland-use category. Median dissolved nitrate and 

median total nitrogen concentrations at sites with 

daily discharge data range from 0.71 mg/L and 1.43 

mg/L, respectively at the Mohawk River at Fonda 

(agricultural) to 0.25 mg/L and 0.51 mg/L, respectively at Esopus Creek at Shandaken (forested). 

Median total phosphorus concentrations at sites with 

daily discharge data range from 0.29 mg/L for the 

Hoosic River at North Petersburg (urban) to less than 

0.01 mg/L at East Sacandaga River at Griffith 

(forested).

Analysis of nutrient data from 32 surface-water 

sites indicates that lowest median nutrient concentrations are at sites representing forested watersheds: the 

median nitrate concentrations range from 0.72 mg/L 

in agricultural watersheds to 0.36 mg/L in forested 

watersheds; median total nitrogen concentrations 

range from 1.4 mg/L in urban and mixed watersheds 

to 0.6 mg/L in forested watersheds; and the median 

total phosphorus concentrations range from 0.08 

mg/L in agricultural watersheds to less than 0.01 

mg/L in forested watersheds. Median nutrient 

concentrations in this data set also are directly related 

to population density and increase with increasing 

population density in watersheds with a population 

density less than 300 per mi2 .

Nutrient yields (mass per year per area) during 

1970-80 and predominant sources of nutrient input 

differ with land use. The highest yields of dissolved 

nitrate and total phosphorus were from agricultural 

watersheds and in urban watersheds with population 

densities exceeding 150 per mi2 . Annual yields for 

dissolved nitrate, total nitrogen, and total phosphorus 

exceeded 3,200 lb/mi 2, 4,200 lb/mi2, and 450 lb/mi2, 

respectively, from drainage areas upstream from four 

sites - Mohawk River at Fonda (agricultural), Hoosic 

River below Williamstown (urban), Hoosic River at 

North Petersburg (urban), and Wallkill River near 

Rosendale (agricultural). The lowest dissolved nitrate 

yields (less than 1,600 lb/mi2) and total nitrogen 

yields (3,400 lb/mi2) were from forested watersheds 

and from parts of the Schoharie Creek watershed at 

sites below significant water diversions. The lowest 

total phosphorus yields (less than 150 lb/mi 2) were 

from forested watersheds.

Suummary and Conclusions 73
The predominant source of nitrogen and phosphorus inputs to a watershed site reflects the land use in 

the watershed. Estimated nutrient inputs represent the 

total amount of nutrients applied to each watershed 

not the actual amounts of nutrients reaching the 

stream. In forested watersheds, 90 percent of the 

nitrogen input is from atmospheric deposition, 

whereas in farmed watersheds, more than 70 percent 

is from fertilizer and manure; in the two urban watersheds, 40 percent of the nitrogen input was from 

treated wastewater. At the mixed land use watersheds 

(including the Hudson River at Green Island), 50 to 

70 percent of the nitrogen input was from fertilizer or 

manure, and the balance was generally split equally 

between atmospheric deposition and treated wastewater. The predominant source of phosphorus input 

in all but the two urban watersheds and two forested 

watersheds is fertilizer and manure. A mass balance 

based on nutrient transport (yield multiplied by 

watershed area) using data for watersheds upstream 

of the Hudson River at Green Island, indicates that 

between 50 and 60 percent of the mass of nutrients 

transported past Green Island comes from the 

Mohawk River basin, even though that basin represents only about 40 percent of the drainage area of the 

Green Island site; this indicates that the Mohawk 

River basin is an important source of nutrients to the 

Hudson River estuary.

Suspended-sediment concentrations and yields in 

the Hudson River basin also are related to land-use 

characteristics. The highest median suspendedsediment concentration (26 mg/L) and the highest 

sediment yield (0.36 (ton/d)/mi2) were at the Mohawk 

River site at Cohoes; the watershed above this site also 

represents the smallest percentage of forest cover of

the eight sites with suspended-sediment data. 

Similarly, watersheds above sites representing the 

highest percentage of forest cover had the lowest 

median suspended-sediment concentrations (less than 

5 mg/L) and lowest yields (less than 0.08 (ton/d)/mi2).

Detection rates for selected persistent pesticide 

compounds in streambed sediment also are related to 

land use. DDT was applied to agricultural, urban, and 

forested watersheds from the 1940's through the 

early 1970's, and total DDT was detected in 

streambed-sediment at concentrations exceeding 0.1 

jig/kg at all but one of the 21 sites with available data. 

Median total DDT streambed-sediment concentrations at the urban sites did not differ significantly 

from those at the other sites. Chlordane, by contrast, 

was applied primarily in urban areas from the 1940's 

through the 1970's, and was detected at concentrations equal to or greater than 2 Jig/kg at more than 80 

percent of the 11 urban sites and at less than 20 

percent of the 11 non-urban sites. In contrast to DDT, 

median chlordane bed-sediment concentrations at 

urban sites were significantly higher than those at 

nonurban sites.

The above results demonstrate that local differences in concentrations of nutrients and suspended 

sediment in surface-water samples and of selected 

pesticides in streambed sediment can be related to 

land-use patterns and the sources and locations of 

nutrient and pesticide inputs. These relations are 

based on data collected during 1970-80, however, and 

do not necessarily reflect current water-quality conditions. In addition, the lack of nutrient and suspendedsediment data from urban sites makes the assessment 

of water-quality conditions in urban streams difficult.

74 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90
REFERENCES CITED

Alexander, R. B., and Smith, R. A., 1990, County-level 

estimates of nitrogen and phosphorus fertilizer use in the 

United States, 1945-1985, U. S.Geological Survey 

Open-File Report 90-130, 12 p.

Ayres, R. U., Ayres, L. W., McCurley, J. Small, M., Tarr, J. 

A., and Widgery, R. C., 1988, An historical reconstruction of major pollutant levels in the Hudson-Raritan 

Basin -1880-1980 [3 volumes], National Ocean Service, 

National Oceanic and Atmospheric Administration, 

Rockville, Md., NOS OMA 43, 139 p.

Bauersfeld, W. R., Moshinsky, E. W., Pustay, E. A., and 

Jones, W. D., 1988, Water Resources Data - New Jersey, 

Water Year 1987, volume 1. Atlantic Slope Basins, 

Hudson River to Cape May: U. S. Geological Survey 

Water-Data Report NJ-87-1, 347 p.

Bode, R. W., Novak, M. A. and Abele, L. E., 1992, Biological stream assessment of Cayadutta Creek, N. Y.: 

Albany, N. Y, New York State Department of Environmental Conservation, Bureau of Monitoring and Assessment, Albany, N.Y, 24 p.

Bopp, R. R, Simpson, H. J., Olsen, C. R., Treier, R. M., and 

Kostyk, Nadia, 1982, Chlorinated hydrocarbons and 

radionuclide chronologies in sediments of the Hudson 

River and Estuary, New York: Environmental Science 

and Technology 16, no. 10, p. 666-676.

Bugliosi, E. R, and Trudell, R. A., 1988a, Potential yields of 

wells in unconsolidated aquifers in upstate New York 

lower Hudson sheet: U.S. Geological Survey WaterResources Investigations Report 87-4274, 1 sheet, scale 

1:250,000.

__ 1988b, Potential yields of wells in unconsolidated 

aquifers in upstate New York Adirondack sheet: U.S. 

Geological Survey Water-Resources Investigations 

Report 87-4276, 1 sheet, scale 1:250,000.

Bugliosi, E. R,Trudell, R. A., and Casey, G. D., 1988, 

Potential yields of wells in unconsolidated aquifers in 

upstate New York Hudson-Mohawk sheet: U.S. 

Geological Survey Water-Resources Investigations 

Report 87-4275, 1 sheet, scale 1: 250,000.

Cohn, T. A., DeLong, L. L., Hirsch, R. M., and Wells, D. K., 

1989, Estimating constituent loads: Water Resources 

Research, v. 25, no. 5, p. 837-942.

Penneman, N. M., 1938, Physiography of eastern United 

States: New York, McGraw-Hill, 691 p.

Pirda, G. D., Lumia, Richard, and Murray, P. M., and 

Preeman, W. O., 1993, Water Resources Data - New 

York, water year 1993, Volume 1. Eastern New York 

excluding Long Island: U. S. Geological Survey WaterData Report NY-93-1, 452 p.

Gianissi, L. P., and C. M. Puffer, 1988, Use of selected 

pesticides for agricultural crop production in the United 

States, 1982-1985: Washington D.C., Resources for the 

Future, 490 p.

Gilroy, E. J., Hirsch, R. M., and Cohn, T. A., 1990, Mean 

square error of regression-based constituent transport 

estimates: Water Resources Research, v. 26, no. 9, p. 

2069-2077.

Hammond, D. S., Heath, R. C., and Waller, R. M., 1978, 

Ground-water data on the Hudson River Basin, New 

York: U. S. Geological Survey Open Pile Report 78-710, 

18 p.

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76 Water-Quality Assessment of Hudson River Basin - Analysis of nutrient, pesticide, and sediment data, 1970-90