U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2008–1203

Prepared in cooperation with Federal Emergency Management Agency

Flood Magnitude and Frequency of the Delaware River in 

New Jersey, New York, and Pennsylvania
Cover. USGS stream-gaging station 01457500, Delaware River at Riegelsville, New Jersey, during 

the April 4, 2005, flood. Photograph taken by Amy McHugh, USGS.
Flood Magnitude and Frequency of the 

Delaware River in New Jersey, New York, 

and Pennsylvania

By Robert D. Schopp and Gary D. Firda

Prepared in cooperation with Federal Emergency Management Agency

Open-File Report 2008–1203

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2008

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Suggested citation:

Schopp, R.D., and Firda, G.D., 2008, Flood magnitude and frequency of the Delaware River in New Jersey, New York, 

and Pennsylvania: U.S. Geological Survey Open-File Report 2008–1203, 7 p.
iii

Contents

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

Introduction.....................................................................................................................................................1

Description of Study Area ............................................................................................................................1

Streamflow Data ............................................................................................................................................3

Trend Analysis ................................................................................................................................................3

Flood Magnitude and Frequency Computation.........................................................................................5

Summary..........................................................................................................................................................6

Acknowledgments.........................................................................................................................................6

References Cited............................................................................................................................................7

Figures

1. Map showing location of U.S. Geological Survey streamflow-gaging stations on the 

Delaware River..............................................................................................................................2

2. Plot showing annual flood peaks recorded on the Delaware River at Trenton, N.J.,

water years 1898-2006 .................................................................................................................4

Tables

1. Streamflow-gaging stations on the main stem Delaware River. ..........................................3

2. Change in estimated forest cover for selected locations along the Delaware River, 

1894 to 1992....................................................................................................................................5

3. Flood magnitude and frequency for streamflow-gaging stations on the main stem 

Delaware River..............................................................................................................................6
iv

Conversion Factors

Multiply By To obtain

Length

inch (in.) 25.4 millimeter (mm)

inch (in.) 0.0254 meter (m)

Area

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)
Flood Magnitude and Frequency of the Delaware River in 

New Jersey, New York, and Pennsylvania

By Robert D. Schopp and Gary D. Firda

Abstract

From September 2004 to June 2006, the Delaware River 

in New Jersey, New York, and Pennsylvania experienced 

three major floods that caused extensive damage. The Federal 

Emergency Management Agency (FEMA) needed updated 

information on the flood magnitude and frequency for the 

eight active streamflow-gaging stations along the main stem 

Delaware River in New Jersey, New York, and Pennsylvania 

that included the three recent floods in order to update its 

flood insurance studies. Therefore, the U.S. Geological Survey 

(USGS) computed updated flood magnitude and frequency 

values following the guidelines published by the Interagency 

Advisory Committee on Water Data in its Bulletin 17B. The 

updated flood-frequency values indicate that the recurrence 

interval of the September 2004 flood ranged from 20 to 35 

years, the recurrence interval of the April 2005 flood ranged 

from 40 to 70 years, and the recurrence interval of the June 

2006 flood ranged from 70 to greater than 100 years. Examination of trends in flood discharges indicate no statistically 

significant trends in peak flows during the period of record for 

any of the eight streamflow-gaging stations.

Introduction

During the 22-month period from September 2004 to 

June 2006, the Delaware River experienced three major 

floods that caused extensive damage. The Federal Emergency 

Management Agency (FEMA) needed updated information on flood magnitude and frequency for the eight active 

streamflow-gaging stations along the main stem Delaware 

River in New Jersey, New York, and Pennsylvania that 

included the three recent floods in order to update its floodinsurance studies for the Delaware. Therefore, the U.S. 

Geological Survey (USGS) computed new flood magnitude 

and frequency values for the eight stations, and examined 

trends in flood discharges. Possible reasons for the occurrence 

of the three high-magnitude floods in a 22-month period were 

also examined.

This report presents the methodology and resulting flood 

magnitude and frequency values, including 2-, 5-, 10-, 25-, 

50-, 100-, and 500-year recurrence intervals, for eight active 

streamflow-gaging stations (stations) on the Delaware River 

and presents the results of the trend analysis. 

The U.S. Army Corps of Engineers (the Corps) and 

FEMA flood-insurance studies have been using a set of 

flood magnitude and frequency values that were initially 

computed in 1962 (U.S. Army Corps of Engineers, 1962) and 

were last updated in 1984 (U.S. Army Corps of Engineers, 

1984). The effects of reservoir storage were removed from 

the observed flood peaks using a HEC-1 computer program 

(U.S. Army, Corps of Engineers, Hydrologic Engineering 

Center, 1973) with the assumption that the reservoirs were 

full at the beginning of the floods. Both analyses (1962 and 

1984) were developed using a mixed population analysis in 

which non-hurricane floods and floods caused by tropical 

storms and hurricanes are analyzed separately. The results 

of the two analyses were then combined, and the combined 

results were readjusted from unregulated conditions to the 

current regulated conditions. The flood-frequency values were 

then graphically combined with USGS computations using 

observed flood-peak discharges.

Description of Study Area

The study area is the main stem of the Delaware River in 

the States of New Jersey, New York, and Pennsylvania. The 

Delaware River has its headwaters in New York State. The 

river has two headwater streams, the East Branch and the West 

Branch; both rise in the Catskill Mountains. The two branches 

join at Hancock, N.Y. From there the river flows downstream 

to Trenton, N.J., which is at the head of tide. The eight active 

and two inactive streamflow-gaging stations include stations 

on the main stem downstream to and including Trenton, N.J. 

Stations farther downstream on the main stem are tidally 

affected and, therefore, are outside the study area. The 

drainage area of the station that is farthest downstream is 

6,780 mi2 and contains nine major reservoirs (fig. 1).
2 Flood Magnitude and Frequency of the Delaware River in New Jersey, New York, and Pennsylvania

!

!

!

!

*#

*#

*#

*#

*#

*#

*#*#

*#

*#

Montague

Delaware Water Gap

Belvidere

Riegelsville

Lambertville

Trenton

Easton

Port Jervis

Hancock

Pennsylvania

New Jersey

New York

Delaware River

Delaware River

76° 75°

41°

42°

Lehigh River

Schuylkill River

Callicoon

Barryville Neversink River

Lackawaxen 

River

Cannonsville

Reservoir

Pepacton 

Reservoir

Neversink

Reservoir

General Edgar

Jadwin Reservoir

Lake 

Wallenpaupack

Francis E. Walter

Reservoir

Beltzville

Lake

Lake

Nockamixon

Prompton

Reservoir

EXPLANATION

*# U.S. Geological Survey streamflow-gaging station

Delaware River Basin boundary

State boundary

Catskill Mountains

0 5 10 MILES

0 5 10 KILOMETERS

West Branch Delaware River

East Branch Delaware River

Figure 1. Location of U.S. Geological Survey streamflow-gaging stations on the Delaware River.
Trend Analysis 3

Streamflow Data

Information on flooding along the Delaware River dates 

back to a major flood that occurred in 1692. Reliable sources 

of historic flood-peak stages and discharges are publications 

by Mangan (1942) and Thomas (1964). These data are available on the World Wide Web at the USGS Peak Flow File web 

site (http://nwis.waterdata.usgs.gov/usa/nwis/peak/). Table 1 

summarizes the peak-flow data available for stations on the 

main stem Delaware River.

Two locations were utilized for gaging in the vicinity of Callicoon, N.Y. (see table 1). The peak-flow records collected 

at the gage 01427410 Delaware River near Callicoon, N.Y. 

(period of record water years 1968–75), were adjusted to the 

present gage site 01427510, Delaware River at Callicoon, 

N.Y., using a simple drainage-area ratio.

Two locations were utilized for gaging in the vicinity 

of Trenton, N.J. (see table 1). The peak-flow records collected at the gage 01462000, Delaware River at Lambertville, 

N.J. (period of record water years 1898-1907, except water 

year 1904), were adjusted to the present gage site 01463500, 

Delaware River at Trenton, N.J., using a simple drainage-area 

ratio. Water years run from October 1 to September 30 and are 

designated by the ending year.

Trend Analysis

A trend analysis was performed on annual peak-flow 

series for the eight long-term main stem gages, including the 

two gages for which records were combined, to determine 

whether an overall trend was present in the peak flows during 

the period of record. The trend test used was the Kendall Tau 

test in the USGS computer program SWSTAT (Lumb and 

others, 1990). None of the gage records showed a statistically 

significant trend at the 95-percent confidence level. Figure 2 

shows a plot of the annual flood peaks versus water year for 

the Delaware River at Trenton, N.J.

Much public discussion has taken place regarding possible reasons for the occurrence of three high flood peaks in 

only a 22-month period. Although, the Kendall Tau test did 

not indicate a statistically significant trend in the flooding, 

possible causes of a change in flood magnitude and frequency 

were examined. Possible reasons for a change in the flood 

magnitude and frequency include:

1. increased impervious cover due to development,

2. changes in the magnitude of flood peaks due to construction of reservoirs in the basin,

3. changes in forest cover in the basin, and

4. changes due to global climate warming and longterm precipitation cycles.

Increases in man-made imperious cover in the basin 

would be expected to increase peak discharges. Increases 

would be greater for low-recurrence interval floods, such as 

the 2- and 5-year floods, than for high-recurrence-interval 

floods. After a few inches of rain have fallen, the soils tend 

to become saturated and act as impervious cover, and do not 

retain much of the subsequent rainfall; therefore, increases in 

flow at the 100-year recurrence interval likely would be fairly 

minor. Preliminary computations using population density 

(which was correlated with the percentage of the basin with 

man-made impervious cover) (Stankowski, 1974) in the Delaware River Basin upstream from Trenton and Stankowski’s 

(1974) equation for estimating the 100-year flood indicate that 

peak discharge would be increased less than 10 percent due to 

population growth between 1900 and 2000.

Table 1. Streamflow-gaging stations on the main stem Delaware River.

[mi2, square miles]

USGS station 

number Station name Drainage area, in mi2 Period of record, in water years1

01427410 Delaware River near Callicoon, N.Y.2 1,708 1968–1975

01427510 Delaware River at Callicoon, N.Y.2 1,820 1976–2006

01428500 Delaware River above Lackawaxen River near Barryville, N.Y. 2,020 1941–2006

01434000 Delaware River at Port Jervis, N.Y. 3,070 1904–2006

01438500 Delaware River at Montague, N.J. 3,480 1904, 1936–2006

01440200 Delaware River near Delaware Water Gap, Pa. 3,850 1955, 1964–1996, 2002–2006

01446500 Delaware River at Belvidere, N.J. 4,535 1904, 1923–2006

01457500 Delaware River at Riegelsville, N.J. 6,328 1841, 1904, 1907–2006

01462000 Delaware River at Lambertville, N.J.3 6,680 1898–1907

01463500 Delaware River at Trenton, N.J.3 6,780 1904, 1913–2006 1

Water years run from October 1 to September 30 and are designated by the ending year.

2

Records for stations 01427410 and 01427510 were combined for the analysis for 01427510.

3

Records for stations 01462000 and 01463500 were combined for the analysis for 01463500.
4 Flood Magnitude and Frequency of the Delaware River in New Jersey, New York, and Pennsylvania

Several major reservoirs have been built in the Delaware 

River Basin upstream from Trenton in the last 100 years 

(fig. 1):

•	 Pepacton Reservoir, New York City water-supply reservoir on East Branch Delaware River, completed 1954;

•	 Cannonsville Reservoir, New York City water-supply 

reservoir on West Branch Delaware River, completed 

1963;

•	 Prompton Reservoir, on Lackawaxen River, U.S. Army 

Corps of Engineers flood-control dam, completed 

1960;

•	 General Edgar Jadwin Reservoir, U.S. Army Corps 

of Engineers flood-control dam on Dyberry Creek, 

completed 1959;

•	 Lake Wallenpaupack, Pennsylvania Power and Light 

Company hydropower facility on Wallenpaupack 

Creek, completed 1925;

Figure 2. Plot showing annual flood peaks recorded on the Delaware River at Trenton, N.J., water years 1898-2006. Accessed July 6, 

2007, at http://nwis.waterdata.usgs.gov/nj/nwis/peak/?site_no=01463500&agency_cd=USGS .

•	 Neversink Reservoir, New York City water-supply 

reservoir on Neversink River, completed 1953;

•	 Francis E. Walter Reservoir, U.S. Army Corps of 

Engineers flood-control reservoir on Lehigh River, 

completed 1961;

•	 Beltzville Lake, U.S. Army Corps of Engineers floodcontrol reservoir on Pohopoco Creek, completed 1971; 

and

•	 Lake Nockamixon, Pennsylvania Department of Environmental Protection water-supply and flood-control 

reservoir on Tohickon Creek, completed 1973.

In almost all cases, whether water levels are at spillway elevation or drawdown, reservoirs will attenuate peak 

discharges because the surface area available for storage is 

larger than that available in the natural floodplain before dam 

construction. This might not be true if there are large gates 

in the dam that release large amounts of water. Some of the 

reservoirs listed above were designed for water supply and do 

not have gates to release large quantities of water.
Flood Magnitude and Frequency Computation 5

Forest cover in the basin was considered as a factor in the 

magnitude of flooding. Table 2 shows changes in estimates of 

percentage forest cover at three locations along the main stem 

Delaware River from 1894 (Vermeule, 1894) to 1992 (U.S. 

Geological Survey, 1992). The methodologies used in the two 

studies differ greatly, but the general conclusions are believed 

to be valid. At all three locations, the percent forest cover has 

increased substantially. Much of the basin was clear cut for 

timber in the late 1800s, or was cleared for farming. Increases 

in percent forest cover typically cause decreases in flood-peak 

discharges.

Global climate warming is expected to raise air temperatures with time. The effects of these higher air temperatures on 

rainfall and flooding in the Delaware River Basin are not clear. 

Various general circulation models yield conflicting projections (Ayers and others, 1994). There are various cyclical 

patterns in rainfall, with some cycles lasting 1 or 2 months, 30 

years, 500, or tens of thousands of years. Studies of streamflow patterns performed by Lins (2005) indicate a shift to a 

wetter period beginning in 1940 and an abrupt shift to an even 

wetter period in the northeastern United States about 1970. 

 Examination of the flood-peak stage data recorded at 

Easton, Pa., (http://nwis.waterdata.usgs.gov/usa/nwis/peak/) 

shows that over the last 300 years, six of the seven highest 

flood stages occurred after 1900, and only one occurred before 

that time, in 1841. The timing of these floods could be attributable to climate cycles greater than 100 years. In this study 

it was decided to use only flood information collected after 

1898, when the first USGS gaging station was established at 

Lambertville, N.J., for this study. Data collected before 1898 

primarily consisted of high-water marks from local residents, 

newspapers, and historic accounts.

Flood Magnitude and Frequency 

Computation

A flood-frequency analysis was conducted on peak-flow 

data using the computer program PeakFQ (Flynn and others, 

2006). The station skew was used for all gages rather than 

the WRC-weighted skew (Interagency Advisory Committee 

on Water Data, Hydrology Subcommittee,1982) because the 

drainage areas were large enough to represent multiple physiographic provinces and most of the gage records were fairly 

long (greater than 50 years). Historic adjustments were applied 

back to 1898 for Trenton and to the 1904 water year for the 

other stations. The base discharge for the historic adjustment 

was set at the 1955 flood-peak discharge.

The Callicoon (01427510) flood frequency analysis was 

adjusted using the two-station comparison procedure described 

in Appendix 7 of Bulletin 17B (Interagency Advisory Committee on Water Data, Hydrology Subcommittee, 1982). The 

Barryville gage (01428500) was used as the long-term record 

in this comparison.

The Montague (01438500) flood-frequency analysis was 

adjusted using the two-station comparison procedure described 

in Appendix 7 of Bulletin 17B (Interagency Advisory Committee on Water Data, Hydrology Subcommittee, 1982). The 

Port Jervis gage (01434000) was used as the long-term record 

in this comparison.

The Delaware Water Gap (01440200) flood-frequency 

analysis was adjusted using the two-station comparison 

procedure described in Appendix 7 of Bulletin 17B (Interagency Advisory Committee on Water Data, Hydrology 

Subcommittee, 1982). The Belvidere gage (01446500) was 

used as the long-term record in this comparison.

The U.S. Army Corps of Engineers (the Corps), Philadelphia District, performed a similar analysis following the 

procedures used in the last update of flood magnitudes and 

frequencies developed for FEMA flood-insurance studies on 

the main stem of the Delaware River. The major change in 

the analysis made by the Corps was to eliminate the mixed 

population analysis that had previously been used to analyze 

hurricane and non-hurricane flooding separately and then 

combine the two analyses. This change was made because of a 

lack of adequate data.

The analysis performed by the Corps involved using a 

HEC-1 computer program (U.S. Army Corps of Engineers, 

Hydrologic Engineering Center, 1973) to remove the affects 

of reservoir attenuation on the observed flood peaks. The 

assumption was made that the major reservoirs in the basin 

were full at the beginning of a storm. The attenuating effects 

of the reservoirs were then computed and used to adjust downstream observed peak. The dates that the various reservoirs 

were completed were taken into account.

The Corps then performed a log-Pearson Type III analysis 

of the unregulated peaks using most of the same assumptions 

used by the USGS. A power equation was developed to relate 

Table 2. Change in estimated forest cover for selected 

locations along the Delaware River, 1894 to 1992.

[All values in percent]

Location 11894 21992 Change

Delaware River above Delaware 

Water Gap, Pa. 59 3

82 +39

Delaware River above Easton, Pa. 55 81 +47

Lehigh River near mouth, Pa. 47 63 +34

Delaware River above Trenton, 

N.J. 51 75 +47

1

C.C. Vermeule (1894, p. 231).

2

 U.S. Geological Survey (1992).

3

 Interpolated value.
6 Flood Magnitude and Frequency of the Delaware River in New Jersey, New York, and Pennsylvania

regulated to unregulated peaks at each gage. These power 

equations were then applied to the flood-frequency values 

developed for the unregulated peaks. The result was a floodfrequency curve for the degree of regulation that existed in 

2006.

The USGS- and Corps-developed flood-frequency values 

were compared; most results were within 5 percent of each 

other values (table 3). The Delaware River Coordinating 

Committee, which includes representatives of the USGS, the 

Corps, FEMA, FEMA contractors, the Delaware River Basin 

Commission, the New Jersey Department of Environmental 

Protection, and the New Jersey Highlands Council, agreed 

to adopt the proposed flood-frequency values developed by 

USGS for use in ongoing FEMA flood insurance studies and 

U.S. Army Corps of Engineers flood studies. 

Included with the flood-magnitude and -frequency results 

presented in table 3 is the New Jersey Flood Hazard Area 

Flood (NJFHAF), which is equal to 125 percent of the updated 

100-year flood magnitude. The NJFHAF is used by the New 

Jersey Department of Environmental Protection to apply their 

flood plain management regulations.

These updated flood-frequency values indicate that the 

recurrence interval of the September 2004 flood ranged from 

20 to 35 years, the recurrence interval of the April 2005 flood 

ranged from 40 to 70 years, and the recurrence interval of the 

June 2006 flood ranged from 70 years in the New Jersey portions of the river to greater than 100 years in the Callicoon and 

Barryville portions of the river.

Summary

From September 2004 to June 2006, the Delaware River 

in New Jersey, New York, and Pennsylvania experienced 

three major floods that caused extensive damage. The U.S. 

Geological Survey (USGS) updated the flood-magnitude and 

-frequency values for the eight streamflow-gaging stations 

along the main stem Delaware River in New Jersey, New 

York, and Pennsylvania for use in (FEMA) flood-insurance 

studies and U.S. Army Corps of Engineers flood-control 

studies. Results of an analysis of trends in flood discharge 

indicated no statistically significant trend in peak flows during 

the period of record for any of the eight stations. The updated 

flood-frequency values indicate that the recurrence interval 

of the September 2004 flood ranged from 20 to 35 years, the 

recurrence interval of the April 2005 flood ranged from 40 to 

70 years, and the recurrence interval of the June 2006 flood 

ranged from 70 to greater than 100 years. 

Acknowledgments

The authors gratefully acknowledge the flood-frequency 

analysis and technical coordination provided by Robert A, 

Lowinski and Glendon T. Stevens of the U.S. Army Corps 

of Engineers, Philadelphia District. We also acknowledge 

Paul Weberg, Mary Colvin, and Jon Janowicz of the Federal 

Emergency Management Agency (Regions II, II, and III, 

respectively) for their input and counsel.

Table 3. Flood magnitude and frequency for streamflow-gaging stations on the main stem Delaware River

[USGS, U.S. Geological Survey; station locations shown in figure 1; ---, not determined; values are discharge, in cubic feet per second]

USGS 

station 

number

Station Name

Recurrence interval

2-year 5-year 10-year 25-year 50-year 100-year NJFHAF1 500-year

01427510 Delaware River at Callicoon, N.Y. 40,100 62,300 78,600 101,000 118,000 137,000 --- 185,000

01428500 Delaware River above Lackawaxen 

River near Barryville, N.Y. 44,100 67,100 83,600 106,000 124,000 142,000 --- 188,000

01434000 Delaware River at Port Jervis, N.Y. 59,500 91,000 114,000 147,000 173,000 201,000 --- 273,000

01438500 Delaware River at Montague, N.J. 65,200 101,000 127,000 164,000 194,000 226,000 282,000 308,000

01440200 Delaware River near Delaware 

Water Gap, Pa. 71,800 110,000 139,000 178,000 210,000 244,000 305,000 332,000

01446500 Delaware River at Belvidere, N.J. 76,900 116,000 145,000 184,000 215,000 248,000 310,000 334,000

01457500 Delaware River at Riegelsville, N.J. 92,300 136,000 167,000 208,000 241,000 274,000 342,000 358,000

01463500 Delaware River at Trenton, N.J. 94,900 138,000 169,000 211,000 245,000 280,000 350,000 372,000

1

New Jersey Flood Hazard Area Flood, equal to 125 percent of the 100-year flood discharge
References Cited 7

References Cited

Ayres, M.A., Wolock, D.M., McCabe, G.J., Hay, L.E., and 

Tasker, G.D., 1994, Sensitivity of water resources in the 

Delaware River Basin to climate variability and change: 

U.S. Geological Survey Water-Supply Paper 2422, 42 p.

Flynn, K.M., Kirby, W.H., and Hummel, P.R., 2006, User’s 

manual for program PeakFQ annual flood-frequency analysis using Bulletin 17B guidelines: U.S. Geological Survey 

Techniques and Methods, book 4, chap. B4, 42 p., 4 app.

Interagency Advisory Committee on Water Data, Hydrology 

Subcommittee, 1982, Guidelines for determining flood flow 

frequency: Bulletin 17B of the Hydrology Subcommittee, 

28 p., 14 app.

Lins, H.F., 2005, Streamflow trends in the United States...

from the National Streamflow Information Program: U.S. 

Geological Survey Fact Sheet 2005–3017, 4 p.

Lumb, A.M., Kittle, J.L., Jr., and Flynn, K.M., 1990, Users 

manual for ANNIE, a computer program for interactive 

hydrologic analyses and data management: U.S. Geological Survey Water-Resources Investigations Report 89-4080, 

236 p.

Mangan, J.W., 1942, The floods of May 1942 in the Delaware 

and Lackawanna River Basins: Commonwealth of Pennsylvania, Department of Forests and Waters, 29 p.

Stankowski, S.J., 1974, Magnitude and frequency of floods 

in New Jersey with effects of urbanization: New Jersey 

Department of Environmental Protection, Division of Water 

Resources, Special Report 38, 46 p.

Thomas, D.M., 1964, Flood magnitude and frequency: 

New Jersey Department of Conservation and Economic 

Development, Division of Water Policy and Supply, Water 

Resources Circular 13, 145 p. 

U.S. Army Corps of Engineers, 1962, Delaware River basin, 

New York, New Jersey, Pennsylvania, and Delaware: letter 

from the Secretary of the Army transmitting a letter from 

the Chief of Engineers, Department of the Army, dated 

April 2, 1962, submitting a report, together with accompanying papers and illustrations, on a review of the Delaware 

River and tributaries, Appendix M. Hydrology: House 

Document 522.

U.S. Army Corps of Engineers, Hydrologic Engineering 

Center, 1973, HEC-1 Flood Hydrograph Package, Users 

Manual: U.S. Army, Corps of Engineers, Hydrologic Engineering Center, 25 p., 6 app.

U.S. Army Corps of Engineers, 1984, Delaware River Basin 

Study, Survey Report, Main Report: 82 p., 4 appendices.

U.S. Geological Survey, 1992, National Land Cover Characterization, accessed December 17, 1997, at http://landcover.

usgs.gov/natllandcover.php .

Vermeule, C.C., 1894, Report on water-supply, water power, 

the flow of streams and attendant phenomena: Geological 

Survey of New Jersey, Volume III of the Final Report of the 

State Geologist: Trenton, N.J., 351 p., 2 app.
8 Flood Magnitude and Frequency of the Delaware River in New Jersey, New York, and Pennsylvania
For additional information, write to:

Director

U.S. Geological Survey

New Jersey Water Science Center

810 Bear Tavern Rd., Suite 206 

West Trenton, NJ 08628

or visit our Web site at:

http://nj.usgs.gov/
Schopp and others—Flood Magnitude and Frequency of the Delaware River in New Jersey, New York, and Pennsylvania—Open-File Report 2008–1203