FLOOD MAGNITUDE AND FREQUENCY OF LITTLE 

TIMBER CREEK AT THE CULVERT ON INTERSTATE 

ROUTE 295 IN HADDON HEIGHTS TOWNSHIP, 

CAMDEN COUNTY, NEW JERSEY 

U.S. GEOLOGICAL SURVEY 

Open-File Report 96-321 

Prepared in cooperation with the 

NEW JERSEY DEPARTMENT OF TRANSPORTATION 
FLOOD MAGNITUDE AND FREQUENCY OF LITTLE 

TIMBER CREEK AT THE CULVERT ON INTERSTATE 

ROUTE 295 IN HADDON HEIGHTS TOWNSHIP, 

CAMDEN COUNTY, NEW JERSEY 

By Thomas Barringer 

u.s. GEOLOGICAL SURVEY 

Open-File Report 96-321 

Prepared in cooperation with the 

NEW JERSEY DEPARTMENT OF TRANSPORTATION 

West Trenton, New Jersey 

1996 
u.s. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITII Secretary 

U.s. GEOLOGICAL SURVEY 

Gordon P. Eaton, Director 

F or additional information Copies of this report can be 

write to: obtained from: 

District Chief U.S Geological Survey 

U.S Geological Swvey Earth Science Information Center 

Mountain View Office Park Open-File Reports Section 

810 Bear Tavern Road, Suite 206 Box 25286, MS 517 

West Trenton, NJ 08628 Denver Federal Center 

Denver, CO 80225 
CONTENTS 

Page 

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

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

Methods for detenniningflood magnitude and frequency ............................................................................ 3 

New Jersey Department of Environmental Protection Special Report 38 method ........................................ 3 

Results ............................................................................................................................................................ 3 

Selected references .................................................................................................. : ..................................... 6 

ILLUSTRATIONS 

Figure 1. Map showing location of Little Timber Creek at the culvert at milepost 28.9 on Interstate 

Route 295 and associated drainage basin, Haddon Heights Township, New Jersey ....... 2 

TABLES 

Table 1. Explanatory variables for the flood-magnitude and -frequency analysis of Little Timber Creek 

at the culvert on Interstate Route 295, Haddon Heights Township, New Jersey ................ 4 

2. Estimates offlood magnitudes for selected flood frequencies, Little Timber Creek at the 

culvert on Interstate Route 295, Haddon Heights Township, New Jersey .......................... 5 

iii 
CONVERSION FACTORS 

Multiply fu: To obtain 

foot (ft) 0.3048 meter 

mile (rni) 1.609 kilometer 

square mile (mi2) 2.590 square kilometer 

foot per mile (ftJmi) 0.189 meter per kilometer 

cubic foot per second (ft3 /s) 0.0283 cubic meter per second 

iv 
FLOOD MAGNITUDE AND FREQUENCY OF LITTLE TIMBER CREEK 

AT THE CULVERT ON INTERSTATE ROUTE 295 IN 

HADDON HEIGHTS TOWNSHIP, CAMDEN COUNTY, NEW JERSEY 

By Thomas Barringer 

ABSTRACT 

The magnitude and frequency of floods at Little TlIDber Creek at the culvert on Interstate Route 

295, at milepost 28.9, in Haddon Heights Township, New Jersey, were determined by using the New Jersey 

Department of Environmental Protection Special Report 38 method. Flood-magnitude and -frequency 

estimates, as well as drainage-basin characteristics, are included in this report. The IOO-year-flood estimate 

is 770 cubic feet per second. 

INTRODUCTION 

Information on the magnitude and frequency of floods is critical to the planning and design of 

highway culverts and bridges. This information is not readily available for many stream crossings in New 

Jersey. To fulfill this information need, the U.S. Geological Survey (USGS), in cooperation with the New 

Jersey Department of Transportation, began an analysis of flood data for stream-crossing sites in 

New Jersey. 

This report presents results of the analysis for Little TlIDber Creek at the culvert on Interstate 

Route 295 at milepost 28,9 Ln Haddon Heights Township, New Jersey. Tne culvert is located about midway between interchanges 28 and 29 of Interstate Route 295 in Haddon Hei~hts Township New Jersey 

(fig. 1). The drainage area upstream from the site is calculated to be 1.61 mi . A field reconnaissance was 

performed on February 23, 1995, to verify the locations of the drainage-basin divides and basin characteristics. Because the direction of storm-sewer drainage in some parts of the basin is uncertain, the calculated 

drainage area is approximate. 

The flood-insurance study for Lawnside Township (Federal Emergency Management Agency, 

1978), in which part of the subject basin lies, does not include a detailed study of this stream. No flood data 

are available for Barrington Township or Haddon Heights Borough; therefore, flood discharges were not 

determined previously by this agency. 

The U.S. Army Corps of Engineers (U.S. Army Corps of Engineers, 1969) analyzed streamflow 

for parts of the Little TImber Creek watershed downstream from the culvert. The Corps reports two types 

of flood discharges: the floodway-design flood and the standard-project flood. The floodway-design flood 

corresponds to the 100-year flood as estimated by the method of Stankowski (1974) (New Jersey Department of Environmental Protection, 1975). The standard-project flood is 1.25 times the floodway-design 

flood, roughly corresponding to the 500-year flood. 

The site which is nearest the culvert and for which flood discharges are reported is at Bell Avenue 

in Bell Mawr/Mt. Ephraim (drainage area is 2.0 mi2

). At that site,'estimated streamflow for the floodwaydesign flood was 500 ft3js. The estimated streamflow for the standard-design flood is 850 ft3js. 

1 
N 

75°02'30" 

Base from U.S. Geological Survey 1 :24,000, quadrangle, 

Runnemede, 1967, revised 1994; Camden, 1967, revised 1994 

41° 

o EXPLANATION 

I 1 MILE I .... _ •• - DRAINAGE-BASIN BOUNDARY I 

o 1 KILOMETER o CULVERT SITE 

39° 

Figure 1. Location of Little Timber Creek at the culvert at milepost 28.9 on Interstate 

Route 295 and associated drainage basin, Haddon Heights Township, New Jersey. 
METHODS FOR DETERMINING FLOOD MAGNITUDE AND FREQUENCY 

Various widely used methods for calculating flood magnitude and frequency were considered for 

use in detellD.ining the flood magnitudes that are likely to be exceeded at this site within a given number of 

years (recurrence interval). The rational method (Chow and others, 1988), New Jersey Department of 

Environmental Protection (NJDEP) Special Report 38 method (SR 38) (Stankowski, 1974), the U.S. Soil 

Conservation Service (SCS) Technical Release 55 (TR-55) method (U.S. Soil Conservation Service, 

1986), the USGS transfer method (New Jersey Department of Environmental Protection, 1988), and the 

index-flood method (Thomas, 1964) were all considered for use in detellD.ining flood magnitude and 

frequency at the subject culvert. 

NEW JERSEY DEPARTMENT OF ENVIRONMENTAL PROTECTION SPECIAL 

REPORT 38 METHOD 

The SR 38 method (Stankowski, 1974) is suitable for the estimation of flood magnitudes at sites 

located in drainage areas greater than 1 mi2

; therefore, the SR 38 method is suitable for use for the subject 

site. 

Flood-magnitude and -frequency estimates computed by using the SR 38 method were compared 

with estimates made by using the USGS transfer method. Estimates made with the USGS transfer method 

required the use of flood data from three streamflow-gaging stations located in basins that have drainage 

areas and other basin characteristics similar to those at the subject site. The stations are located within a 

23-mi radius of the culvert. 

EstL.T!ates of the 1OO-year flood at the subject site produced with t."'1e USGS transfer met."'1od were 

1.1 and 1.2 times that of the SR 38 estimates made with flood data from two stations (South Branch 

Newton Creek at Haddon Heights, N.J., 01467317 and West Branch Cohansey River at Seeley, N.J., 

01412500, respectively) and 0.5 that of the SR 38 estimate made with flood data from a third station (Newton Creek at Collingswood, N.J., 01467305). The estimates made by using the SR 38 method agreed 

closely with the estimates made by using the USGS transfer method; therefore, the SR 38 estimate was 

chosen for this analysis. 

RESULTS 

Flood data from nearby streamflow or crest-stage gaging stations provide a good indication of the 

flood magnitude and frequency that can be expected at an ungaged site, particularly when drainage area 

and other basin characteristics are similar. In this study, estimates were obtained by using the NJDEP 

SR 38 method and were compared with estimates made by using the USGS transfer method. 

The explanatory variabls used in applying the USGS transfer method for the culvert site are listed 

in table 1. The flood-magnitude and -frequency estimates made by using the SR 38 method are shown in 

table 2. The estimate of the 100-year flood discharge at the culvert site is 770 ft3/s. 

The difference between the U.S. Anny Corps of Engineers estimate of the floodway-design flood 

at Bell Avenue site (500 3 ft /s) and the lOO-year flood at the study site is attributed to differences in degree 

of basin development, increases in sewering and channelization, and improvements in methodology that 

have occurred in the 25 years since the floodway .. design flood and standard-project flood studies were 

conducted. 

3 
Table 1. ExplanatOry variables for the flood-magnitude and -frequency analysis of Little Tunber Creek at 

the culvert on Interstate Route 295, Haddon Heights Township, New Jersey 

Drainage area: 1.61 square miles 

Latitude: 39° 52' 19" 

Longitude: 75° 04' 04" 

Highway: Interstate Route 295 

Milepost: 28.9 

U.S. Geological Survey 7-1/2-minute quadrangles: Camden, N.J.-Pa., Runnemede, N.J. 

Variable Value Unit 

Drainage area = 1.61 square miles 

Main-channel slope = 29.9 feet per mile 

Surface-storage index = 1.00 percent 

Total stream length = 2.22 mile 

Population density (1990) - '1'"7 A 0 :J1""tU persons per square mile 

Impervious cover = 25 percent 

Lake and swamp area = 0.0 percent 

4 
Table 2. Estimates of flood magnitudes for selected flood frequencies, Little Timber Creek at the culvert on 

Interstate Route 295, Haddon Heights Township, New Jersey 

[Q, flood-magnitude estimates in cubic feet per second along with number, indicating recurrence-interval 

frequency in years; NJDEP SR, New Jersey Department of Environmental Protection Special Report] 

Drainage area: 1.61 square miles 

Latitude: 39° 52' 19" 

Longitude: 75° 074' 04" 

Highway: Interstate Route 295 

Milepost: 28.9 

U.S. Geological Survey 7-l/2-minute quadrangles: Camden, N.J.-Pa., Runnemede, N.J. 

Estimating method Q2 Q5 Q10 Q25 Q50 Q100 

NJDEP SR 38 204 296 391 526 631 770 

5 
SELECTED REFERENCES 

Chow, V.T., Maidment, D.R., and Mays, L.W., 1988, Applied hydrology: New York, McGraw-Hill, 572 p. 

Federal Emergency Management Agency, 1978, Flood insurance study of the Borough of Lawnside, 

Camden County, New Jersey: Federal Emergency Management Agency, March 1978, 13 p. 

New Jersey Department of Environmental Protection, 1975, Delineation of flood hazard areas, Raritan 

River Basin: New Jersey Department of Environmental Protection, 16 p. 7 pIs. 

New Jersey Department of Environmental Protection, 1988, Technical manual for stream encroachment: 

New Jersey Department of Environmental Protection, Division of Water Resources, Bureau of 

Floodplain Management, 151 p., 6 app. 

Stankowski, S.1., 1974, Magnitude and frequency of floods in New Jersey with effects ofurbartization: 

New Jersey Department of Environmental Protection Special Report 38, 46 p. 

Thomas, DM., 1964, Floods in New Jersey, magnitude and frequency: New Jersey Department of 

Conservation and Economic Development, Water Resources Circular 13,145 p. 

U.S. Army Corps of Engineers, 1969, Flood plain information Little Timber Creek, Camden County, New 

Jersey: U.S. Army Corps of Engineers, Philadelphia District, 34 p., 11 pIs. 

U.S. Soil Conservation Service, 1986, Urban hydrology for small watersheds: Engineering Division 

Technical Release 55, Washington, D.C., 162 p. 

6