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

Scientific Investigations Report 2008-5102

In cooperation with the Federal Emergency Management Agency, the Pennsylvania State

Association of Township Supervisors, and the Susquehanna River Basin Commission

Regression Equations for Estimating Flood Flows at Selected Recurrence Intervals for Ungaged Streams in Pennsylvania


By Mark A. Roland and Marla H. Stuckey

In cooperation with the Federal Emergency Management Agency, the Pennsylvania State Association of Township Supervisors, and the Susquehanna River Basin Commission

Scientific Investigations Report 2008–5102

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

U.S. Department of the InteriorDIRK KEMPTHORNE, Secretary

U.S. Geological SurveyMark D. Myers, Director

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

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Suggested citation:Roland, M.A., and Stuckey, M.H., 2008, Regression equations for estimating flood flows at selected recurrence inter-vals for ungaged streams in Pennsylvania: U.S. Geological Survey Scientific Investigations Report 2008-5102, 57 p.

iii

Contents

Abstract ...........................................................................................................................................................1Introduction.....................................................................................................................................................1

Purpose and Scope ..............................................................................................................................1Previous Studies ...................................................................................................................................2

Development of Regression Equations ......................................................................................................2Selection of Streamflow-Gaging Stations ........................................................................................2Basin Characteristics ...........................................................................................................................4Regression Analysis .............................................................................................................................4

Flood-Flow Regression Equations ...............................................................................................................4Limitations of Regression Equations ........................................................................................................15Summary........................................................................................................................................................15Acknowledgments .......................................................................................................................................16References Cited..........................................................................................................................................16Appendix 1. Streamflow-gaging stations and basin characteristics used in development of

flood-flow regression equations for Pennsylvania streams ...................................................20Appendix 2. Flood-flow magnitudes for selected recurrence intervals computed from

observed streamflow-gaging data, predicted from regional regression equations, and a weighted average for streamflow-gaging stations used in analysis .................................30

Appendix 3. Flood-flow magnitudes for selected recurrence intervals for streamflow-gaging stations in Pennsylvania with drainage areas less than 2,000 square miles and streamflow substantially affected by upstream regulation .....................55

Figures 1-6. Maps showing

1. Streamflow-gaging stations used in development of flood-flow regression equations for Pennsylvania streams ..................................................................................3

2. Flood-flow regions and hydrologic unit code boundaries in Pennsylvania ..................7 3. Flood-flow region 1 in Pennsylvania ....................................................................................8 4. Flood-flow region 2 in Pennsylvania ....................................................................................9 5. Flood-flow region 3 in Pennsylvania ..................................................................................11 6. Flood-flow region 4 in Pennsylvania ..................................................................................12

iv

Tables 1. Basin characteristics selected for use in the development of regression equations

for flood-flow estimates ...............................................................................................................5 2. Number of streamflow-gaging stations and area in flood-flow regions in

Pennsylvania and surrounding states .....................................................................................10 3. Regression coefficients for use with flood-flow regression equations for

Pennsylvania streams ................................................................................................................13 4. Equivalent period of record for regression equations developed for estimating flood

magnitudes for selected recurrence intervals in Pennsylvania .........................................14 5. Summary of the variables used to develop the flood-flow regression equations for

Pennsylvania ...............................................................................................................................15

v

Conversion Factors

Multiply By To obtainLength

inch (in.) 2.54 centimeter (cm)inch (in.) 25.4 millimeter (mm)foot (ft) 0.3048 meter (m)mile (mi) 1.609 kilometer (km)

Areasquare mile (mi2) 2.590 square kilometer (km2)

Flow ratecubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)inch per hour (in/h) 0.0254 meter per hour (m/h)

Hydraulic gradientfoot per mile (ft/mi) 0.1894 meter per kilometer (m/km)

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.

AbstractRegression equations were developed for estimat-

ing flood flows at selected recurrence intervals for ungaged streams in Pennsylvania with drainage areas less than 2,000 square miles. These equations were developed utilizing peak-flow data from 322 streamflow-gaging stations within Pennsylvania and surrounding states. All stations used in the development of the equations had 10 or more years of record and included active and discontinued continuous-record as well as crest-stage partial-record stations. The state was divided into four regions, and regional regression equations were developed to estimate the 2-, 5-, 10-, 50-, 100-, and 500-year recurrence-interval flood flows. The equations were developed by means of a regression analysis that utilized basin characteristics and flow data associated with the stations.

Significant explanatory variables at the 95-percent con-fidence level for one or more regression equations included the following basin characteristics: drainage area; mean basin elevation; and the percentages of carbonate bedrock, urban area, and storage within a basin. The regression equations can be used to predict the magnitude of flood flows for specified recurrence intervals for most streams in the state; however, they are not valid for streams with drainage areas generally greater than 2,000 square miles or with substantial regulation, diversion, or mining activity within the basin. Estimates of flood-flow magnitude and frequency for streamflow-gaging stations substantially affected by upstream regulation are also presented.

IntroductionInformation on the frequency and magnitude of floods is

essential for Flood Insurance Studies (FIS), flood-plain man-agement, and the design of bridges and flood-control struc-tures. Accurate and accessible methods that produce flood-flow statistics are important to engineers and planners working on such projects. Flood-flow statistics commonly used in flood-related projects include the magnitude of flood flows

occurring, on average, once in 2, 5, 10, 50, 100, and 500 years (Q2, Q5, Q10, Q50, Q100, and Q500, respectively). These flood flows are estimates based on statistical probabilities or frequencies, and the recurrence intervals associated with each flood flow refer to the average number of years between the floods (Dinicola, 1996). For example, the Q100 has a 1 in 100 chance (or 0.01 probability or frequency) that a flood of this magnitude will occur in any given year.

Regression equations for computing the magnitude and frequency of peak flows were last developed for Pennsylvania by the U.S. Geological Survey (USGS) by use of peak-flow data collected through 1997 (Stuckey and Reed, 2000). Flood-ing experienced in the northern and eastern parts of Penn-sylvania subsequent to 1997 prompted an analysis of flood-magnitude and flood-frequency data through the 2006 water year1 for streamflow-gaging stations with at least 25 years of record in the Delaware and Susquehanna River Basins in Pennsylvania (Roland and Stuckey, 2007). The results of that study, other recent flooding across the state, and advances in geospatially derived basin characteristics warranted updating the flood-flow regression equations for Pennsylvania.

The USGS, in cooperation with the Federal Emergency Management Agency (FEMA), the Pennsylvania State Asso-ciation of Township Supervisors (PSATS), and the Susque-hanna River Basin Commission (SRBC), developed updated flood-flow regression equations for use on ungaged streams in Pennsylvania. Regression equations were developed to esti-mate the Q2, Q5, Q10, Q50, Q100, and Q500 flood flows for streams without substantial regulation, diversion, or mining activity in the basin. This report discusses the methodology used and presents the results of the regression analysis.

Purpose and Scope

This report presents regression equations that describe the statistical relation between expected flood magnitudes and basin characteristics for selected recurrence intervals

1Water year is defined as a 12-month period beginning October 1 and end-ing September 30. The water year is designated by the calendar year in which it ends.


By Mark A. Roland and Marla H. Stuckey

2 Regression Equations for Estimating Flood Flows for Ungaged Streams in Pennsylvania

for ungaged streams in Pennsylvania. Flood-flow regression equations were developed by use of peak-flow data from 277 continuous-record2 and 45 crest-stage partial-record3 stream-flow-gaging stations in Pennsylvania and surrounding states—New York, Ohio, Maryland, and West Virginia—with 10 or more years of record generally through the 2005 water year. Peak-flow data were used through the 2006 water year for 39 stations in the Delaware and North Branch Susquehanna River Basins that experienced severe flooding in June 2006. Flood-flow data are also presented for the Q2, Q5, Q10, Q50, Q100, and Q500 along with basin characteristics computed from the station data.

Previous Studies

Regression equations used to predict flood frequency-magnitude relations for ungaged streams in Pennsylvania were first published by Flippo in 1977 and were updated by Flippo in 1982. The equations published in 1982 were evaluated by Ehlke and Reed (1999) on the basis of a comparison between flood flows calculated from the regression equations and peak-flow data collected through the 1996 water year. Regression equations for estimating magnitude of flood flows in Penn-sylvania for selected recurrence intervals were last published in 2000 using data through the 1997 water year (Stuckey and Reed, 2000).

Development of Regression EquationsFlood flows for selected recurrence intervals were com-

puted using peak streamflow data from gaging stations with flow relatively unaffected by regulation, diversion, or mining. Methods used are described in Water Resource Council Bul-letin 17B (Water Resources Council, Hydrology Committee, 1981). These flood flows will be referred to as “observed” in this report. The terms ‘peak flows’ and ‘flood flows’ may be used interchangeably in common parlance; however, within this report, an attempt is made to maintain consistency with regard to usage. The use of ‘peak flows’ is associated with flows that are more or less measured at a streamflow-gaging station and are associated with a period of observation (year). The term ‘flood flow’ is reserved for a more extreme event typically not measured directly and that is associated with a recurrence interval.

Basin characteristics known to affect streamflow, such as land cover, were determined for the drainage basins upstream from the gaging stations. The observed flood flows (dependent

2Continuous-record station is a site where stage or streamflow is recorded at some interval on a continuous basis. The recording interval is usually 15 minutes but may be less or more frequent.

3Partial-record station is a site where discrete measurements of one or more hydrologic parameters are obtained over a period of time without continuous data being recorded or computed. A common example is a crest-stage gage partial-record station at which only peak stages and flows are recorded.

variable) were related to the basin characteristics (independent or explanatory variables) using regression techniques to obtain regression equations. These equations can be used to compute flood flows for selected recurrence intervals for streams where no gaging-station data are available. The flood flows com-puted from regression equations will be referred to as “pre-dicted” in this report.

Selection of Streamflow-Gaging Stations

Peak-flow data generally through the 2005 water year from 306 stations on streams in Pennsylvania, along with peak-flow data from stations in surrounding states, including 6 stations in New York, 5 in Ohio, 3 in Maryland, and 2 in West Virginia, with flow relatively unaffected by regulation, diversions, and mining were used in the development of the regression equations (fig. 1). In addition, peak-flow data for water year 2006 were used for 39 stations in the Delaware and North Branch Susquehanna River Basins that experienced severe flooding due to heavy rains occurring June 23, 2006, through June 29, 2006.

Stations included in the analysis had 10 or more years of record and drainage areas less than 2,000 mi2. The stations were selected on the basis of information about regulation, diversions, and mining published in the USGS Pennsylvania Water Resources Data Reports, Surface-Water-Supply Reports, and other scientific reports. In the event of regulation, diver-sion, or mining occurring within a basin during the period of record, only the period of record prior to the event was used in the analysis. For stations that had a gap in the operational his-tory, the total number of years the station was in actual opera-tion was used to determine the period of record. A list of the stations used in the development of the regression equations is provided in appendix 1.

Peak flows may be recorded outside of the streamflow-gaging station operational period (also referred to as the systematic period of record) to document major flood events. These peaks are termed “historical peaks” and may be used to supplement the period of record at a station. If historical peaks are used in the analysis, the period of record at the sta-tion is adjusted to include the total number of years from the historical peak to the operational period of record, which may include a period when the station was not in operation (Water Resources Council, Hydrology Committee, 1981). This situ-ation affected a small number of stations used in the analysis and typically added few years to the period of record. Because of the inherent uncertainty associated with historical peaks, not all historical peaks were included in the analysis. Typi-cally, historical peaks were included in the analysis if the peak was not the maximum peak of record for the station or if the peak was recorded less than 5 years outside the period during which the station operated. Other factors such as knowledge about a particular event or previous USGS publications were considered as part of the decision to include a historical peak. For example, station 01539000, Fishing Creek near Blooms-

Development of Regression Equations 3

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burg, Pa., began continuous operation in 1939, but a historical peak was recorded in 1936. Subsequently, the period of record used in the analysis included the period between 1936 and 1939, when the station was not in operation.

Basin Characteristics

A set of 24 climatologic, geologic, hydrologic, and physiographic basin characteristics with possible effects on peak flow was compiled from various geographic information system (GIS) sources. The use of GIS-derived basin charac-teristics in the development of regression equations improved consistency, reproducibility, and ease of use. The basin char-acteristics evaluated in the exploratory regression analysis are presented in table 1.

Regression Analysis

The observed flood-flow frequency statistics were computed for the 306 Pennsylvania stations and were related to the basin characteristics using exploratory Ordinary Least Squares (OLS) and Weighted Least Squares (WLS) regression techniques. The flood flows calculated for each streamflow-gaging station for specified recurrence intervals were weighted for comparison purposes to OLS on the basis of the period of record, [(number of years of record at station * number of sta-tions)/sum of years of record of all stations], and incorporated into the WLS analysis (Helsel and Hirsch, 1992). Regression iterations were performed using a statistical software pack-age, S-PLUS (MathSoft, Inc., 1997), to reduce the number of explanatory variables to those significant at the 95-percent confidence level. Flood-flow and basin-characteristic data for the 16 out-of-state stations were obtained from previously published USGS reports (Dillow, 1996; Lumia and others, 2006; Koltun, 2003; Wiley and others, 2000). Because limited data were available for these sites, they were excluded from the exploratory regression-analysis techniques. Each set of regression equations was constrained to contain the same explanatory variables in an attempt to maintain a monotonic relation between frequency and magnitude for all possible sites, whether the same explanatory variables were significant at all recurrence intervals. Diagnostics used to further evalu-ate the adequacy of the regression models included graphical relations, multicollinearity, standard error, and coefficient of determination (R2) (Helsel and Hirsch, 1992).

The observed flood flows computed according to the guidelines in Bulletin 17B (Water Resources Council, Hydrology Committee, 1981) and the significant explanatory variables found using OLS and WLS were then related using a Generalized Least Squares (GLS) regression analysis to obtain the final regression equation. GLS is considered to be a more accurate regression technique for hydrologic regressions, particularly when using differing record lengths (Tasker and Stedinger, 1989). In addition to differing record lengths, the technique also takes into account variance of flows and cross-

correlation among the stations used in the analysis (Tasker and Stedinger, 1989). This regression technique was incorporated into a USGS software package, GLSNET (Tasker and Sted-inger, 1989), and was used in this analysis.

Flood-Flow Regression EquationsData from 322 stations within Pennsylvania and from sur-

rounding states were used to develop the Q2, Q5, Q10, Q50, Q100, and Q500 flood-flow regression equations. Exploratory regression analysis using OLS and WLS indicated the need for the state to be regionalized. A comparative analysis was done between the updated statewide regression residual values, standard errors, and R2 and those published by Stuckey and Reed (2000) for the previously developed flood-flow regions. Exploratory regressions using these previously defined flood-flow regions in association with the updated peak-flow data did not produce diagnostic statistics indicative of a significant improvement over those resulting from the statewide regres-sion developed using OLS and WLS for the updated Q100 flood flow. Therefore, statewide regression residuals and basin flood-flow yields at the 100-year recurrence interval were used to create four flood-flow regions for the state (fig. 2). The basin flood-flow yields were computed for each station, in cubic feet per second per square mile, by dividing the Q100 flood flow by the respective drainage area. The regionalization process consisted of generating plots of the Q100 regression residual values and basin flood-flow yields for each of the 322 stations included in the study area. These plots were evaluated and regionalized on the basis of similar values. Physiographic provinces and precipitation maps were also used in the delin-eation of the four flood-flow regions. Hydrologic unit code (HUC8) boundaries were followed wherever possible while delineating the flood-flow regions to avoid dividing water-sheds into multiple regions. The Schuylkill River Basin (HUC 02040203) was divided on the basis of differing basin and geologic characteristics.

The North Branch Susquehanna River Basin, parts of the West Branch Susquehanna River Basin, and most of the northern Delaware River Basin are within flood-flow region 1 (fig. 3). The southern part of the Delaware River Basin, including Philadelphia and surrounding areas, and the lower part of the Susquehanna River Basin are within flood-flow region 2 (fig. 4). The Schuylkill River Basin, within the Delaware River Basin, was split between regions 1 and 2; the upper part of the basin is in region 1 and the lower part, down to the mouth, is in region 2. This split was based on statewide regression diagnostics and differing hydrologic characteris-tics between the two parts of the basin. Flood-flow region 3 extends from south-central Pennsylvania northwest to the state borders of New York, Ohio, and West Virginia, encompass-ing parts of the Susquehanna, Ohio, and St. Lawrence River Basins (fig. 5). The Potomac and parts of the Ohio River Basin in the southwestern part of Pennsylvania are within flood-flow

Flood-Flow Regression Equations 5

Table 1. Basin characteristics selected for use in the development of regression equations for flood-flow estimates.—Continued

Basin characteristic Source Reference

Dependent Variables

Estimates of flood flows for the 2-, 5-, 10-, 50-, 100-, and 500-year recurrence inter-vals (expressed in cubic feet per second)

Derived by application of PeakFQ computer program that performs statistical flood-frequency analyses of peak flows recorded at U.S. Geological Survey streamflow-gaging stations following procedures recommended in Water Resources Council Bulletin 17B

streamflow data: U.S. Geological Survey (http://waterdata.usgs.gov/pa/nwis/)

PeakFQ computer program: Flynn and others (2006)

Independent Variables

Basin slope (degrees) Digital Elevation Model (DEM) U.S. Geological Survey (2000a)Mean basin elevation (feet) Digital Elevation Model (DEM) U.S. Geological Survey (2000a)

Forested (percent of basin area) National Land Cover Dataset (NLCD); and enhanced ver-sion (NLCDe)

Homer and others (2004); Price and others (2003)

Glaciated (percent of basin area) From modified geology maps

Pennsylvania Dept. of Con-servation and Natural Re-sources (1997); Environmental Resources Research Institute (1996)

Lakes and open water (percent of basin area)

National Land Cover Dataset (NLCD); and enhanced ver-sion (NLCDe); digitized from USGS quadrangle maps 1:24000 scale


Longest drainage path (mile) National Hydrography Dataset (NHD), 1:24000 scale U.S. Geological Survey (2000b)Stream density (length, in miles, per basin

area, in square miles) National Hydrography Dataset (NHD), 1:24000 scale U.S. Geological Survey (2000b)

Channel slope (feet per mile) Digital Elevation Model (DEM) U.S. Geological Survey (2000a)Soil infiltration index (unitless, 1=well to

4=poor) State Soil Geographic (STATSGO) database U.S. Department of Agriculture (1994)

Mean annual precipitation, 1971-2000 (inches)

Parameter-elevation Regressions on Independent Slopes Model (PRISM) Daly (1996)

Drainage area (square miles) Digital Elevation Model (DEM) U.S. Geological Survey (2000a)

Soil thickness, depth to bedrock (feet) State Soil Geographic (STATSGO) database U.S. Department of Agriculture (1994)

Drainage run-off curve (unitless, 1=well to 7=poor) State Soil Geographic (STATSGO) database U.S. Department of Agriculture

(1994)

Soil available water content (percent) State Soil Geographic (STATSGO) database U.S. Department of Agriculture (1994)

Soil permeability (inches per hour) State Soil Geographic (STATSGO) database U.S. Department of Agriculture (1994)

Urbanized area (percent of basin area) National Land Cover Dataset (NLCD); and enhanced ver-sion (NLCDe)


Residential area (percent of basin area) National Land Cover Dataset enhanced version (NLCDe) Price and others (2003)Mined area (percent of basin area) National Land Cover Dataset enhanced version (NLCDe) Price and others (2003)Commercial, industrial & transportation

area (percent of basin area) National Land Cover Dataset enhanced version (NLCDe) Price and others (2003)

Wetlands (percent of basin area) National Land Cover Dataset (NLCD); and enhanced ver-sion (NLCDe)


Ground-water head, defined as mean basin elevation minus minimum elevation (feet)

Digital Elevation Model (DEM) U.S. Geological Survey (2000a)


Table 1. Basin characteristics selected for use in the development of regression equations for flood-flow estimates.—Continued

Basin characteristic Source Reference

Shape factor (unitless) is a measure of the shape of a basin computed as the ratio of length of the basin to its computed area

Digital Elevation Model (DEM) U.S. Geological Survey (2000a)

Carbonate bedrock (percent of basin area) From modified geology maps

Pennsylvania Dept. of Con-servation and Natural Re-sources (1997); Environmental Resources Research Institute (1996)

Impervious surface area (percent of basin area) National Land Cover Dataset (NLCD) Homer and others (2004)


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400

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re

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anna River

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Figu

re 4

. Fl

ood-

flow

regi

on 2

in P

enns

ylva

nia.

Susq

ueha

nna R

iver

Susq

ueha

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are Rive

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region 4 (fig. 6). The number of streamflow-gaging stations used to develop each flood-flow region and the area of each region are listed in table 2. The largest region is region 3, accounting for almost half the area in the state.

The following basin characteristics were statistically sig-nificant for one or more regression equations: drainage area, mean elevation, and the percentages of carbonate bedrock, urban area, and storage within the basin. A list of the basin characteristics for the stations used in the analysis is provided in appendix 1. When applying the regression equations to estimate flood magnitudes and frequency, it is important to maintain the same source of basin-characteristic data that were used in the development of the equations. Otherwise, the flood flows predicted by the regression equations may not be valid. To form a near-linear relation between the flood flows and basin characteristics, all independent and dependent variables were log-transformed prior to regression analysis. Because percentages can have a value of zero, 1.0 was added to the decimal form of the percentages of carbonate bedrock, urban area, and storage before the log transformation. Percentage of storage was derived from the percentage of lakes, ponds, and wetlands basin characteristics. To increase the variability of the basin characteristic storage area, a multiplication factor of 10 was applied to the decimal form of the basin characteris-tic, in effect resulting in storage area being multiplied by 0.1 rather than 0.01 prior to log transformation, as the other basin characteristics are.

The regression model took the following form in log units:

LogQ A bLogDA cLogEldLog C eLog U

fLog

T^

( . ) ( . )(

= + + +

+ + + +1 0 01 1 0 0111 0 1+ . )Sto (1)

Or, in arithmetic space:

A El C

U StoT

A b c d

e f

^ ( ) ( ) ( . )

( . ) ( . )

= +

+ +

10 1 0 01

1 0 01 1 0 1

Q D

(2)

where Log = log to base 10; QT

^ =theT-yearpredictedfloodflow,incubicfeetper second;

A = the intercept (estimated by GLS); DA = drainage area, in square miles; El = mean elevation, in feet; C = basin underlain by carbonate bedrock, in

percent; U = urban area in the basin, in percent; Sto = storage in the basin, in percent; and b, c, d, e, and f =basincharacteristiccoefficientsof

regression estimated by GLS.

Regression equations predicting flood magnitudes for the 2-, 5-, 10-, 50-, 100-, and 500-year recurrence intervals were developed for each flood-flow region. The resultant basin-characteristic coefficients along with the standard errors of prediction for the regional flood-flow regression equations are shown in table 3. The standard errors of prediction provide an estimate of reliability of the predicted flood flows (Helsel and Hirsch, 1992). The standard errors of prediction for the flood-flow regression equations ranged from 26 percent for the Q5 in Region 4 to 49 percent for the Q500, also in Region 4. The standard errors of prediction for the Q100 ranged from 36 to 38 percent.

Example using a flood-flow regression equation.Example 1. Calculate the Q100 flood flow for a site near

the confluence of Shohola Creek with the Delaware River in Pike County in the northeastern part of Pennsylvania at latitude 41°25’30” and longitude 74°57’20”. The drainage area

Table 2. Number of streamflow-gaging stations and area in flood-flow regions in Pennsylvania and surrounding states.

Flood-flow region1

Area (square miles)

Number of in-state continuous-record

stations

Number of out-of-state

continuous-record stations

Number of in-state partial-record

stations

Total number of stations

1 12,216 73 4 14 912 4,356 50 0 5 553 22,020 105 7 20 1324 6,710 33 5 6 44

Total 45,302 261 16 45 3221Flood-flow regions are shown on figure 2.


Figu

re 5

. Fl

ood-

flow

regi

on 3

in P

enns

ylva

nia.

4213

000

PEN

NSY

LVA

NIA

OH

IO

NEW

YO

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MA

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ND

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000

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0

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200

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1547

500

1547

100

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1573

160

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560

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500

LAK

E E

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Ohio

River

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iver

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ranc

h Su

sque

hanna River

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3109

000

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390


Figu

re 6

. Fl

ood-

flow

regi

on 4

in P

enns

ylva

nia.30

4900

0

3042

170

3042

200

3047

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800

3042

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29°

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and

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W, L

atitu

de o

f Orig

in 2

3°00

’N

010

2030

4050

MIL

ES

010

2030

4050

KILO

MET

ERS

77°

79°

80°

81°

78°

41°

40°

39°

FLOO

D-FL

OW R

EGIO

N 4

STAT

E BO

UNDA

RY

RIVE

RCo

ntin

uous

-rec

ord

stre

amflo

w-g

agin

g st

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nCr

est-s

tage

par

tial-r

ecor

d st

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flow

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ing

stat

ion

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ANAT

ION

STRE

AMFL

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G ST

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NUM

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(FIR

ST N

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AS R

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ED)

3082

200

3042

170


Table 3. Regression coefficients for use with flood-flow regression equations for Pennsylvania streams.

[ft3/s, cubic feet per second; --, basin characteristic not significant]

T-year peak flow

(ft3/s)Intercept

Basin-characteristic coefficients Standard error of

prediction Coefficient of

determination (R2)

Drainage area1

Mean elevation2

Percent carbonate bedrock3

Percent urban area4

Percent storage5

Log units Percent

Region 1

Q2 1.84257 0.86396 -- -- -- -0.49180 0.14 33 0.95Q5 2.10658 .84127 -- -- -- -.49148 .13 31 .95Q10 2.24305 .83197 -- -- -- -.47595 .13 31 .95Q50 2.47845 .81981 -- -- -- -.43501 .15 36 .92Q100 2.56172 .81626 -- -- -- -.41724 .16 38 .90Q500 2.73185 .81002 -- -- -- -.37550 .19 46 .85

Region 2

Q2 2.20340 .69782 -- -0.47534 0.91196 -- .17 41 .88Q5 2.50745 .66365 -- -.65666 .56109 -- .15 36 .89Q10 2.66804 .64853 -- -.75941 .39037 -- .14 33 .88Q50 2.94676 .62615 -- -.92098 .11100 -- .14 33 .84Q100 3.04617 .61864 -- -.97299 .00947 -- .15 36 .81Q500 3.25362 .60294 -- -1.07780 -.21084 -- .17 41 .71

Region 3

Q2 3.27469 .82143 -0.4517 -1.96079 -- -.74815 .13 31 .96Q5 3.73436 .79492 -.51761 -1.78595 -- -.90039 .12 28 .96Q10 3.98972 .78127 -.55653 -1.66440 -- -.99420 .12 28 .96Q50 4.42545 .75816 -.62224 -1.45536 -- -1.15401 .13 31 .93Q100 4.5808 .75043 -.64613 -1.38215 -- -1.20941 .15 36 .92Q500 4.90955 .73500 -.69814 -1.22437 -- -1.32521 .18 43 .87

Region 4

Q2 1.82330 .84471 -- -- -- -- .12 28 .97Q5 2.09191 .81363 -- -- -- -- .11 26 .97Q10 2.23878 .79689 -- -- -- -- .12 28 .96Q50 2.50038 .77079 -- -- -- -- .14 33 .94Q100 2.59407 .76279 -- -- -- -- .16 38 .93Q500 2.78822 .74809 -- -- -- -- .20 49 .88

1 Drainage area, in square miles, determined from 30-meter digital elevation model (DEM).2 Mean elevation, in feet, is the average elevation in the basin, determined from 30-meter DEM.3 Percent carbonate bedrock is the percent of basin underlain by carbonate bedrock, determined by modified geology maps.4 Percent urban area is the percent of urban area, as defined by low-intensity residential, high-intensity residential, commercial/industrial/transpor-

tation, residential with trees, and residential without trees in the basin, determined by National Land Cover Dataset enhanced (NLCDe).5 Percent storage is the percent of lakes, ponds, and wetlands, determined from U.S. Geological Survey 1:24,000 quadrangles and NLCDe.


is 77.0 mi2, and the percent storage is 10.2. The basin is unaf-fected by substantial regulation, diversion, or mining.

From figure 2 and the latitude and longitude, the 1. site is in flood-flow region 1.

Using coefficients from table 3, the Q100 2. regional regression equation is: logQ^ 100 = 2.56172 + 0.81626 log(DA) – 0.41724 log(1 + (0.1 × Sto))

Substituting the basin characteristics for the site 3. into the equation produces: logQ^ 100 = 2.56172 + 0.81626 log(77.0) - 0.41724 log(1 + (0.1 × 10.2)) logQ^ 100 = 2.56172 + (1.53987) - (0.12740) logQ^ 100 = 3.97419 Q^100 = 9,420 ft3/s

Just as a station has a period of record that should be taken into consideration when computing flood frequencies from gaging-station peak-flow data, regression equations have an equivalent period of record that should be taken into con-sideration when using the equations to compute flood frequen-cies. The equivalent years of record provide indicators of the accuracy of the regression equations. The equivalent years of record are computed from a factor that is based on the skew coefficient of the population of annual peaks, the standard deviation of the logarithms of the annual peaks at individual stations used in the development of the regression equations, and the standard error of prediction of the regression equa-tions. This methodology is presented by Hardison (1971). The equivalent years of record for each of the regression equations are shown in table 4. For the Q100, the equivalent period

of record ranges from 11 years for Region 3 to 15 years for Region 2. To summarize, the Q100 calculated from the equa-tion developed for Region 3 is comparable to the Q100 deter-mined from a record from a station that has been in operation for 11 years.

A weighted method to minimize the temporal bias associated with stations has been suggested by Flippo (1977), Stuckey and Reed (2000), Water Resources Council, Hydrol-ogy Committee (1981), and others to compute flood-flow statistics for a streamflow-gaging station. Observed flood frequency-magnitude estimates may contain time-sampling variability because of the specific time span associated with the period of record for a station. The period of record for a station may or may not include years when large floods occurred. Inclusion of several large floods, or lack of any large floods, can change flood frequency-magnitude estimates for stations, especially those with short periods of record. To minimize this bias, a method has been developed that incor-porates the observed, as well as the predicted, flood flows into a weighted average flood-frequency discharge estimate using the period of record of the station and the equivalent period of record for the regression equation.

The weighted average discharge estimates are computed from the equation:

QQ N Q NE

N NET W

T G T R

( )

( ) ( )

( )=

( )+ ( )

+

^

where QT(W) =theweightedflooddischargefortheT-year

recurrence interval, in cubic feet per second;

QT(G) =theobservedflooddischargecomputedfromstreamflow-gaging-stationdataforthe T-year recurrence interval, in cubic feet

Table 4. Equivalent period of record for regression equations developed for estimating flood magnitudes for selected recurrence intervals in Pennsylvania.

[Methodology used described by Hardison (1971); flood-flow regions are shown in figure 2]

Flood-recurrence interval

Equivalent period of record (years)

Flood-flow region 1 Flood-flow region 2 Flood-flow region 3 Flood-flow region 4

2-year 3 2 3 45-year 6 4 5 710-year 9 7 7 1050-year 13 13 11 13100-year 13 15 11 13500-year 14 16 11 12

Limitations of Regression Equations 15

per second; N = the number of years of record at the

streamflow-gaging station used to calculate QT(G);

QT R^( ) = the predicted flood discharge computed

from regression equations for the T-year recurrence interval, in cubic feet per second; and

NE = average equivalent years of record associated with the regression equation in table 4.

Example showing the calculation of weighted flood flows.Example 2. Calculate the weighted flood-frequency

discharge estimate for streamflow-gaging station 01546400, Spring Creek at Houserville, Pa., at latitude 40°50’01” and longitude 77°49’40”. The drainage area is 58.5 mi2, mean ele-vation is 1,340 ft, percentage of carbonate bedrock is 75.1, and the basin contains 0.13 percent storage. The station operated from 1985 to 2005 as a continuous-record station, for a total of 21 years. The basin is unaffected by regulation, diversion, or mining. The reported Q100 determined from streamflow data is 2,840 ft3/s.

The Q100 computed from the regional regression 1. equation is 3,500 ft3/s (see Example 1 for meth-odology), and from table 4, the equivalent years of record for the regression equation is 11 years.

Substituting the discharges and number of years 2. into equation 2 produces: Q100(W) = [(2,840 × 21) + (3,500 × 11)] / (21 + 11)Q100(W) = 3,070 ft3/s

The observed, predicted, and weighted flood flows for the stations used in the analysis are shown in appendix 2. Additional techniques for estimating magnitude of flood flows at selected recurrence intervals in Pennsylvania under other situations have been identified by Stuckey and Reed (2000).

Limitations of Regression EquationsCertain conditions can limit the application of the regres-

sion equations presented in this report. The equations should not be used if the drainage area is less than 1.0 mi2 or greater than 2,000 mi2. Regions 1, 3, and 4 do not include a vari-able for percentage of urban development in the regression equations, and as a result, effects from urbanization may not be captured in regression-equation results for these regions. A summary of the range of all the variables used to develop the regression equations is presented in table 5. Predicted streamflow characteristics for basins with basin characteristics outside these ranges may not be valid. Particularly, regres-sion equations developed for regions 1 and 3 are sensitive to percent storage, and results from these regression equations should be reviewed carefully to determine accuracy for basins with percent storage outside the range listed in table 5. When applying the regression equations to estimate flood mag-nitudes and frequency, it is important to maintain the same source of basin-characteristic data that were used in the devel-opment of the equations. Otherwise, the flood flows predicted by the regression equations may not be valid.

The regression equations should not be used to predict flood flows if streamflow at the site of interest is substantially affected by an upstream flood-control reservoir. The stream-flow-gaging stations that were excluded from the regression analysis because of substantial upstream regulation are listed in appendix 3 with observed flood flows for specified recur-rence intervals. The 500-year recurrence flow is not listed in the appendix because the storage capacity for some flood-control reservoirs may not be sufficient to store all the runoff associated with the 500-year flood event.

SummaryFlood-flow statistics provide the foundation for Flood

Insurance Studies (FIS), flood-plain management, and the design of bridges and flood-control structures. Accessible

Table 5. Summary of the variables used to develop the flood-flow regression equations for Pennsylvania.

[mi2, square miles; ft, feet]

Flood-flow region

Number of stations

used

Range of basin-characteristic variables

Drainage area (mi2)

Mean elevation

(ft)

Percent urban area

Percent carbonate bedrock

Percent storage

1 91 1.72 - 1,280 0 - 1,960 0 - 20 0 - 83 0 - 21.22 55 2.02 - 1,150 113 - 901 0 - 94 0 - 67 0 - 3.63 132 1.44 - 1,610 457 - 2,150 0 - 64 0 - 99 0 - 22.64 44 .92 - 1,720 553 - 2,700 0 - 67 0 - 42 0 - 2.4


methods that produce estimates of the frequency and magni-tude of floods are important to engineers and planners working on such projects. The USGS, in cooperation with the Federal Emergency Management Agency (FEMA), the Pennsylvania State Association of Township Supervisors (PSATS), and the Susquehanna River Basin Commission (SRBC), developed flood-flow regression equations to estimate flood flows for ungaged streams in Pennsylvania using data from 322 contin-uous-record and crest-stage partial-record streamflow-gaging stations with 10 or more years of record in Pennsylvania and surrounding states.

Regression equations were developed to estimate the Q2, Q5, Q10, Q50, Q100, and Q500 flood discharges for four flood-flow regions in Pennsylvania. The following basin char-acteristics were significant at the 95-percent confidence level for one or more regression equations: drainage area, mean elevation, and the percentages of carbonate bedrock, urban area, and storage within the basin. Standard errors of predic-tion ranged from 26 percent for the Q5 in Region 4 to 49 per-cent for the Q500, also in Region 4. The equivalent periods of record for the Q100 regression equations ranged from 11 years for Region 3 to 15 years for Region 2. To minimize temporal bias that may be associated with a station, a weighting method is presented that incorporates the observed, as well as the pre-dicted, flood flows into a weighted-average flood-frequency discharge estimate.

Certain conditions can limit the application of the regres-sion equations presented in this report. The equations should not be used if the contributing drainage area is less than 1.0 mi2 or greater than 2,000 mi2. The regression equations should not be used to predict flood-flow frequency statistics if streamflow at the site of interest is substantially affected by an upstream flood-control reservoir. Estimates of flood-flow magnitude for streamflow-gaging stations substantially affected by upstream regulation are presented. Predicted streamflow characteristics for basins with basin characteristics outside the ranges used to develop the regression equations may not be valid.

AcknowledgmentsSpecial thanks are extended to the USGS Pennsylvania

Water Science Center (and Maryland, New York, Ohio, West Virginia) Hydrologic Surveillance Program staffs for their compilation and meticulous review of station data that were used to determine the observed flood frequencies. David Holtschlag (USGS Michigan Water Science Center) and Kara Watson (USGS New Jersey Water Science Center) provided critical colleague reviews.

References Cited

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References Cited 19

Appendixes

Appendix 1. Streamflow-gaging stations and basin characteristics used in development of flood-flow regression equations for Pennsylvania streams.

Appendix 2. Flood-flow magnitudes for selected recurrence intervals computed from observed streamflow-gaging data, predicted from regional regression equations, and a weighted average for streamflow-gaging stations used in analysis.

Appendix 3. Flood-flow magnitudes for selected recurrence intervals for streamflow-gaging stations in Pennsylvania with drainage areas less than 2,000 square miles and streamflow substantially affected by upstream regulation.

20 Regression Equations for Estimating Flood Flows at Selected Recurrence IntervalsA

ppen

dix

1.

Stre

amflo

w-g

agin

g st

atio

ns a

nd b

asin

cha

ract

eris

tics

used

in d

evel

opm

ent o

f flo

od-fl

ow re

gres

sion

equ

atio

ns fo

r Pen

nsyl

vani

a st

ream

s.—

Cont

inue

d

[C, c

ontin

uous

-rec

ord

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ion;

P, p

artia

l-rec

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stat

ion;

ddm

mss

, deg

rees

, min

utes

, sec

onds

; mi²,

squa

re m

iles;

ft, f

eet;

--, n

ot u

sed

in re

gres

sion

ana

lysi

s]

U.S

. Geo

logi

cal

Surv

ey

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ng s

tatio

n nu

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r

Type

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ude

(ddm

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)Lo

ngitu

de

(ddm

mss

)St

atio

n na

me

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od o

f re

cord

1 (w

ater

ye

ar)2

Num

ber o

f ye

ars

used

in

ana

lysi

s3

Bas

in c

hara

cter

istic

s

Dra

inag

e ar

ea

(mi2 )

Mea

n el

evat

ion

(ft)

Perc

ent

carb

on-

ate

bedr

ock

Perc

ent

stor

age

Perc

ent

urba

n ar

ea

0142

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out C

reek

at C

anno

nsvi

lle, N

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1941

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001

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N.Y

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35W

est B

ranc

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ckaw

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er n

ear A

lden

ville

, Pa.

1975

-200

632

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1,75

00

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ark

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ek a

t Milf

ord,

Pa.

1962

-200

645

5.09

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00

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ush

Kill

at S

hoem

aker

s, Pa

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011

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0300

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ill C

reek

at M

ount

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ome,

Pa.

1961

-200

646

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00

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12.8

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ead

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k, P

a.19

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701

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nea

r Stro

udsb

urg,

Pa.

1911

-195

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3.17

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ead

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ek a

t Min

isin

k H

ills,

Pa.

1951

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259

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t Ban

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1961

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gh R

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ville

, Pa.

1942

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ock

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ek n

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ong

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, Pa.

1966

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7536

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nna

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ek n

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lake

slee

, Pa.

1955

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00

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gh R

iver

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013

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wn

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ek n

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ong

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, Pa.

1949

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00

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high

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poco

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t Kre

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640

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00

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7.3

0144

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7533

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ild C

reek

at H

atch

ery,

Pa.

1941

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818

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00

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0000

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ashi

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mer

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Pa.

1940

-200

667

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867

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1000

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high

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er a

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ort,

Pa.

1942

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514

889

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515.

5401

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00C

4034

5675

2860

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e Le

high

Cre

ek n

ear A

llent

own,

Pa.

1935

-200

661

80.8

532

63.7

.73

1301

4516

50C

4035

4775

2828

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e Le

high

Cre

ek a

t Ten

th S

t. B

r. at

Alle

ntow

n, P

a.19

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006

2098

509

69.4

.76

19.8

0145

1800

C40

3942

7537

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rdan

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ek n

ear S

chne

cksv

ille,

Pa.

1967

-200

640

5367

50

.35

1.79

0145

2000

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rdan

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t Alle

ntow

n, P

a.19

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9601

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nch

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y C

reek

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a.19

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981

195.

5362

319

.51.

067.

3601

4525

00C

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2875

2247

Mon

ocac

y C

reek

at B

ethl

ehem

, Pa.

1945

-200

662

44.5

494

62.8

.94

12.8

Appendix 1 21A

ppen

dix

1.

Stre

amflo

w-g

agin

g st

atio

ns a

nd b

asin

cha

ract

eris

tics

used

in d

evel

opm

ent o

f flo

od-fl

ow re

gres

sion

equ

atio

ns fo

r Pen

nsyl

vani

a st

ream

s.—

Cont

inue

d

[C, c

ontin

uous

-rec

ord

stat

ion;

P, p

artia

l-rec

ord

stat

ion;

ddm

mss

, deg

rees

, min

utes

, sec

onds

; mi²,

squa

re m

iles;

ft, f

eet;

--, n

ot u

sed

in re

gres

sion

ana

lysi

s]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-

gagi

ng s

tatio

n nu

mbe

r

Type

Latit

ude

(ddm

mss

)Lo

ngitu

de

(ddm

mss

)St

atio

n na

me

Peri

od o

f re

cord

1 (w

ater

ye

ar)2

Num

ber o

f ye

ars

used

in

ana

lysi

s3

Bas

in c

hara

cter

istic

s

Dra

inag

e ar

ea

(mi2 )

Mea

n el

evat

ion

(ft)

Perc

ent

carb

on-

ate

bedr

ock

Perc

ent

stor

age

Perc

ent

urba

n ar

ea

0145

3000

C40

3655

7522

45Le

high

Riv

er a

t Bet

hleh

em, P

a.19

06-2

005

511,

280

1,17

011

4.92

8.4

0145

4600

C40

3405

7519

45Po

lk V

alle

y R

un a

t Hel

lerto

wn,

Pa.

1963

-198

018

1.72

649

23.2

1.09

.02

0145

9500

C40

2601

7507

01To

hick

on C

reek

nea

r Pip

ersv

ille,

Pa.

1936

-200

538

97.4

509

05.

034.

8601

4655

00C

4010

2674

5726

Nes

ham

iny

Cre

ek n

ear L

angh

orne

, Pa.

1933

-200

674

210

305

1.83

1.00

26.8

0146

5770

C40

0755

7459

40Po

ques

sing

Cre

ek a

t Tre

vose

Roa

d, P

hila

., Pa

.19

65-1

981

175.

0921

54.

31.5

590

0146

5785

C40

0522

7459

37W

alto

n R

un a

t Phi

lade

lphi

a, P

a.19

65-1

978

142.

1714

20

.79

67.1

0146

5790

C40

0454

7458

57B

yber

ry C

reek

at C

halfo

nt R

oad,

Phi

la.,

Pa.

1966

-197

813

5.34

133

01.

9768

0146

5798

C40

0325

7459

08Po

ques

sing

Cre

ek a

t Gra

nt A

ve. a

t Phi

lade

lphi

a, P

a.19

66-2

006

4121

.413

31.

032.

5776

.301

4670

42C

4005

2375

0410

Penn

yPac

k C

reek

at P

ine

Roa

d, a

t Phi

lade

lphi

a, P

a.19

65-1

981

1737

.926

01.

88.8

172

.401

4670

43C

4005

2775

0315

Stre

am ‘A

’ at P

hila

delp

hia,

Pa.

1965

-198

016

2.7

175

0.6

094

.401

4670

48C

4003

0075

0159

Penn

yPac

k C

r at L

ower

Rha

wn

St B

dg, P

hila

., Pa

.19

66-2

006

4149

.823

31.

43.8

874

.401

4670

50C

4003

1975

0122

Woo

den

Brid

ge R

un a

t Phi

lade

lphi

a, P

a.19

65-1

981

173.

3611

30

.66

6701

4670

86C

4002

4775

0640

Taco

ny C

reek

at C

ount

y Li

ne, P

hila

delp

hia,

Pa.

1966

-198

621

16.6

254

0.5

486

.701

4670

87C

4000

5775

0550

Fran

kfor

d C

reek

at C

asto

r Ave

, Phi

lade

lphi

a, P

a.19

82-2

005

2430

.422

00

.34

88.8

0146

7089

C40

0025

7505

33Fr

ankf

ord

Cre

ek a

t Tor

resd

ale A

ve.,

Phila

., Pa

.19

66-1

981

1633

.820

60

.36

89.6

0146

8500

C40

3745

7607

30Sc

huyl

kill

Riv

er a

t Lan

ding

ville

, Pa.

1942

-200

642

133

1,11

00

1.56

8.61

0146

9500

C40

4825

7558

20Li

ttle

Schu

ylki

ll R

iver

at T

amaq

ua, P

a.19

20-2

006

8742

.91,

380

02.

643.

9601

4705

00C

4031

2175

5955

Schu

ylki

ll R

iver

at B

erne

, Pa.

1942

-200

665

355

1,02

0.1

21.

745.

7401

4707

20C

4034

2375

5234

Mai

den

Cre

ek T

ribut

ary

at L

enha

rtsvi

lle, P

a.19

62-1

980

187.

4664

20

.21

.87

0147

0756

C40

3051

7552

60M

aide

n C

reek

at V

irgin

ville

, Pa.

1973

-199

523

159

665

10.8

.80

1.34

0147

0779

C40

2448

7610

19Tu

lpeh

ocke

n C

reek

nea

r Ber

nvill

e, P

a.19

72-2

006

3366

.552

383

.2.6

84.

5101

4708

53C

4020

2476

0837

Furn

ace

Cre

ek a

t Rob

eson

ia, P

a.19

83-2

005

235.

797

80

.40

.03

0147

0960

C40

2214

7601

32Tu

lpeh

ocke

n C

r at B

lue

Mar

sh D

amsi

te n

ear R

eadi

ng, P

a..

1965

-200

514

175

544

42.1

1.94

3.08

0147

1000

C40

2208

7558

46Tu

lpeh

ocke

n C

reek

nea

r Rea

ding

, Pa.

1951

-200

528

211

529

41.3

1.70

3.94

0147

1510

C40

2005

7556

12Sc

huyl

kill

Riv

er a

t Rea

ding

, Pa.

1757

-193

029

880

740

191.

545.

5601

4718

75C

4020

2275

4433

Man

ataw

ny C

reek

nea

r Spa

ngsv

ille,

Pa.

1994

-200

613

56.9

670

28.5

1.40

1.55

0147

1980

C40

1622

7540

49M

anat

awny

Cre

ek n

ear P

otts

tow

n, P

a.19

72-2

006

3285

.558

826

.11.

042.

2201

4720

00C

4014

3075

3907

Schu

ylki

ll R

iver

at P

otts

tow

n, P

a.19

02-2

005

511,

150

684

18.7

1.42

6.55

0147

2157

C40

0905

7536

06Fr

ench

Cre

ek n

ear P

hoen

ixvi

lle, P

a.19

69-2

006

3859

.153

0.6

21.

321.

7601

4721

74C

4005

2275

3750

Pick

erin

g C

reek

nea

r Che

ster

Spr

ings

, Pa.

1967

-198

317

5.98

439

0.2

87.

2801

4721

98C

4023

3875

3057

Perk

iom

en C

reek

at E

ast G

reen

ville

, Pa.

1982

-200

524

3862

33.

351.

422.

9801

4721

99C

4022

2675

3122

Wes

t Bra

nch

Perk

iom

en C

reek

at H

illeg

ass,

Pa.

1982

-200

524

2368

54.

761.

202.

4601

4726

20C

4024

1475

1405

East

Bra

nch

Perk

iom

en C

reek

nea

r Dub

lin, P

a.19

84-2

005

224.

0742

00

1.64

.36

0147

3000

C40

1346

7527

07Pe

rkio

men

Cre

ek a

t Gra

terf

ord,

Pa.

1915

-200

591

279

468

1.27

1.46

6.67

0147

3100

P40

1226

7521

57Za

char

ias C

reek

nea

r Ski

ppac

k, P

a.19

60-1

980

217.

2932

20

.06

9.65


ppen

dix

1.

Stre

amflo

w-g

agin

g st

atio

ns a

nd b

asin

cha

ract

eris

tics

used

in d

evel

opm

ent o

f flo

od-fl

ow re

gres

sion

equ

atio

ns fo

r Pen

nsyl

vani

a st

ream

s.—

Cont

inue

d

[C, c

ontin

uous

-rec

ord

stat

ion;

P, p

artia

l-rec

ord

stat

ion;

ddm

mss

, deg

rees

, min

utes

, sec

onds

; mi²,

squa

re m

iles;

ft, f

eet;

--, n

ot u

sed

in re

gres

sion

ana

lysi

s]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-

gagi

ng s

tatio

n nu

mbe

r

Type

Latit

ude

(ddm

mss

)Lo

ngitu

de

(ddm

mss

)St

atio

n na

me

Peri

od o

f re

cord

1 (w

ater

ye

ar)2

Num

ber o

f ye

ars

used

in

ana

lysi

s3

Bas

in c

hara

cter

istic

s

Dra

inag

e ar

ea

(mi2 )

Mea

n el

evat

ion

(ft)

Perc

ent

carb

on-

ate

bedr

ock

Perc

ent

stor

age

Perc

ent

urba

n ar

ea

0147

3120

C40

0952

7526

01Sk

ippa

ck C

reek

nea

r Col

lege

ville

, Pa.

1966

-199

429

53.7

289

00.

1624

.701

4731

69C

4004

4575

2740

Valle

y C

reek

at P

a. T

urnp

ike

Br n

ear V

alle

y Fo

rge,

Pa.

1983

-200

523

20.8

356

66.9

.54

42.9

0147

3880

P40

0813

7511

21Pi

ne R

un T

ribut

ary

at F

ort W

ashi

ngto

n, P

a.19

62-1

979

182.

0228

70

.19

62.9

0147

3900

C40

0726

7513

13W

issa

hick

on C

reek

at F

ort W

ashi

ngto

n, P

a.19

62-2

006

2540

.530

27.

66.4

053

.601

4739

50C

4004

5075

1335

Wis

sahi

ckon

Cr a

t Bel

ls M

ill R

d, P

hila

., Pa

.19

66-1

981

1653

.628

519

.1.5

055

.201

4740

00C

4004

4575

1343

Wis

sahi

ckon

Cre

ek a

t Mou

th, P

hila

delp

hia,

Pa.

1966

-200

540

6428

416

.53

57.4

0147

5300

C40

0121

7525

20D

arby

Cre

ek a

t Wat

erlo

o M

ills n

ear D

evon

, Pa.

1972

-199

926

5.1

435

0.2

567

.201

4755

10C

3955

4475

1622

Dar

by C

reek

nea

r Dar

by, P

a.19

64-1

990

2737

.432

50

.33

75.1

0147

5530

C39

5829

7516

49C

obbs

Cr a

t U.S

. Hgh

wy

No.

1 a

t Phi

lade

lphi

a, P

a.19

65-2

005

184.

7831

90

.42

87.7

0147

5550

C39

5502

7514

52C

obbs

Cre

ek a

t Dar

by, P

a.19

64-1

990

2722

208

0.3

087

.401

4758

50C

3958

3575

2613

Cru

m C

reek

nea

r New

tow

n Sq

uare

, Pa.

1977

-200

529

15.8

420

0.3

430

.701

4764

80C

3954

5875

2413

Rid

ley

Cre

ek a

t Med

ia, P

a.19

87-2

005

1830

.237

40

.36

23.4

0147

6500

C39

5410

7523

35R

idle

y C

reek

at M

oyla

n, P

a.19

32-1

955

2431

.936

80

.37

26.6

0147

7000

C39

5208

7524

31C

hest

er C

reek

nea

r Che

ster

, Pa.

1932

-200

675

61.1

339

0.5

638

.101

4782

00C

3946

5475

4803

Mid

dle

Bra

nch

Whi

te C

lay

Cre

ek n

ear L

ande

nber

g, P

a.19

60-1

995

3212

.745

24.

89.8

66.

9101

4798

20C

3949

0075

4131

Red

Cla

y C

reek

nea

r Ken

nett

Squa

re, P

a.19

88-2

005

1828

.337

111

.11.

2417

.601

4803

00C

4004

2275

5140

Wes

t Bra

nch

Bra

ndyw

ine

Cre

ek n

ear H

oney

Bro

ok, P

a.19

60-2

006

4718

.772

63.

362.

262.

6101

4805

00C

3959

0875

4940

Wes

t Bra

nch

Bra

ndyw

ine

Cre

ek a

t Coa

tesv

ille,

Pa.

1942

-200

645

46.1

663

1.35

1.50

4.33

0148

0610

P39

5820

7551

06Su

cker

Run

nea

r Coa

tesv

ille,

Pa.

1964

-200

539

2.62

544

25.0

821

.401

4806

17C

3957

4275

4806

Wes

t Bra

nch

Bra

ndyw

ine

Cre

ek a

t Mod

ena,

Pa.

1970

-200

637

55.3

633

5.34

1.27

10.5

0148

0800

C40

0020

7542

20Ea

st B

ranc

h B

rand

ywin

e C

reek

at D

owni

ngto

wn,

Pa.

1942

-196

811

81.6

531

6.72

2.03

9.03

0148

1000

C39

5211

7535

37B

rand

ywin

e C

reek

at C

hadd

s For

d, P

a.19

12-2

006

8728

749

07.

631.

0611

.701

5140

00C

4207

4576

1615

Ow

ego

Cre

ek n

ear O

weg

o, N

.Y.

1930

-199

970

185

----

.28

--01

5163

50C

4147

3977

0450

Tiog

a R

iver

nea

r Man

sfie

ld, P

a.19

72-2

005

3415

31,

870

0.2

41.

4501

5165

00C

4147

2777

0054

Cor

ey C

reek

nea

r Mai

nesb

urg,

Pa.

1955

-200

652

12.2

1,77

00

.32

.06

0151

6800

P41

4919

7705

50M

anns

Cre

ek n

ear M

ansf

ield

, Pa.

1960

-197

717

3.04

1,52

00

.01

001

5170

00C

4148

5476

5755

Elk

Run

nea

r Mai

nesb

urg,

Pa.

1955

-197

824

10.2

1,81

00

.03

.02

0151

8000

C41

5430

7707

47Ti

oga

Riv

er a

t Tio

ga, P

a.18

89-2

005

3928

21,

770

0.2

51.

2601

5184

20P

4150

3377

1625

Cro

oked

Cr b

l Cat

lin H

ollo

w a

t Mid

dleb

ury

Cen

ter,

Pa.

1985

-200

520

74.4

1,71

00

.24

.35

0151

8500

C41

5408

7708

55C

rook

ed C

reek

at T

ioga

, Pa.

1954

-197

421

122

1,67

00

.39

.45

0151

8862

C41

5523

7731

56C

owan

esqu

e R

iver

at W

estfi

eld,

Pa.

1984

-200

521

90.6

1,96

00

.26

.78

0151

9200

P41

5915

7718

09C

owan

esqu

e R

iver

at E

lkla

nd, P

a.19

80-2

005

2623

41,

850

0.1

3.5

101

5200

00C

4159

4877

0825

Cow

anes

que

Riv

er n

ear L

awre

ncev

ille,

Pa.

1952

-200

527

298

1,78

00

.15

.53

0152

6000

C42

0400

7717

02Tu

scar

ora

Cre

ek n

ear S

outh

Add

ison

, N.Y

.19

37-1

972

4611

4--

0.2

10

0153

2000

C41

4225

7629

06To

wan

da C

reek

nea

r Mon

roet

on, P

a.19

14-2

006

9321

51,

600

0.4

9.5

7

Appendix 1 23A

ppen

dix

1.

Stre

amflo

w-g

agin

g st

atio

ns a

nd b

asin

cha

ract

eris

tics

used

in d

evel

opm

ent o

f flo

od-fl

ow re

gres

sion

equ

atio

ns fo

r Pen

nsyl

vani

a st

ream

s.—

Cont

inue

d

[C, c

ontin

uous

-rec

ord

stat

ion;

P, p

artia

l-rec

ord

stat

ion;

ddm

mss

, deg

rees

, min

utes

, sec

onds

; mi²,

squa

re m

iles;

ft, f

eet;

--, n

ot u

sed

in re

gres

sion

ana

lysi

s]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-

gagi

ng s

tatio

n nu

mbe

r

Type

Latit

ude

(ddm

mss

)Lo

ngitu

de

(ddm

mss

)St

atio

n na

me

Peri

od o

f re

cord

1 (w

ater

ye

ar)2

Num

ber o

f ye

ars

used

in

ana

lysi

s3

Bas

in c

hara

cter

istic

s

Dra

inag

e ar

ea

(mi2 )

Mea

n el

evat

ion

(ft)

Perc

ent

carb

on-

ate

bedr

ock

Perc

ent

stor

age

Perc

ent

urba

n ar

ea

0153

2200

P41

3525

7625

60So

uth

Bra

nch

Tow

anda

Cre

ek a

t New

Alb

any,

Pa.

1963

-199

530

13.4

1,56

00

0.25

0.06

0153

2850

C41

5145

7600

26M

B W

yalu

sing

Cre

ek n

ear B

ircha

rdvi

lle, P

a.19

60-1

979

205.

671,

480

0.2

4.0

601

5332

50P

4142

2576

0710

Tusc

aror

a C

reek

nea

r Silv

ara,

Pa.

1963

-199

533

11.8

1,25

00

1.81

.16

0153

3800

C41

4810

7538

40B

utle

r Cre

ek a

t Gib

son,

Pa.

1963

-197

915

7.51

1,60

00

2.40

.43

0153

3950

C41

3429

7538

32SB

Tun

khan

nock

Cre

ek n

ear M

ontd

ale,

Pa.

1961

-197

818

12.6

1,51

00

3.65

2.1

0153

4000

C41

3330

7553

42Tu

nkha

nnoc

k C

reek

nea

r Tun

khan

nock

, Pa.

1914

-200

693

383

1,33

00

2.87

3.06

0153

4500

C41

3016

7532

33La

ckaw

anna

Riv

er a

t Arc

hbal

d, P

a.19

40-2

005

2010

81,

730

02.

827.

0301

5360

00C

4121

3375

4441

Lack

awan

na R

iver

at O

ld F

orge

, Pa.

1939

-200

521

335

1,54

00

3.04

17.5

0153

8000

C41

0333

7605

38W

apw

allo

pen

Cre

ek n

ear W

apw

allo

pen,

Pa.

1920

-200

687

43.8

1,38

00

4.33

11.1

0153

8800

P41

1840

7608

50H

untin

gton

Cre

ek n

ear P

ikes

Cre

ek, P

a.19

60-1

980

214.

971,

580

0.1

1.0

601

5390

00C

4104

4176

2553

Fish

ing

Cre

ek n

ear B

loom

sbur

g, P

a.19

36-2

006

7127

41,

320

0.6

7.3

0153

9500

C41

0450

7630

40Li

ttle

Fish

ing

Cre

ek a

t Eye

rs G

rove

, Pa.

1941

-195

818

56.5

1,08

00

.13

.65

0154

0000

C41

0010

7627

50Fi

shin

g C

reek

at B

loom

sbur

g, P

a.19

14-1

931

1835

51,

230

.14

.56

.66

0154

0200

C40

5110

7616

48Tr

exle

r Run

nea

r Rin

gtow

n, P

a.19

59-1

979

211.

771,

440

0.3

00

0154

1000

C40

5349

7840

38W

est B

ranc

h Su

sque

hann

a R

iver

at B

ower

, Pa.

1889

-200

592

315

1,72

00

.10

1.83

0154

1200

C40

5741

7831

10W

B S

usqu

ehan

na R

iver

nea

r Cur

wen

svill

e, P

a.19

56-1

965

1036

71,

700

0.4

21.

6301

5415

00C

4058

1878

2422

Cle

arfie

ld C

reek

at D

imel

ing,

Pa.

1914

-200

547

371

1,71

00

.87

1.44

0154

2000

C40

5058

7816

05M

osha

nnon

Cre

ek a

t Osc

eola

Mill

s, Pa

.19

36-1

993

5268

.71,

820

0.0

72.

5101

5425

00C

4107

0378

0633

WB

Sus

queh

anna

Riv

er a

t Kar

thau

s, Pa

.19

36-2

005

211,

460

1,71

00

.51

1.93

0154

2720

P41

1258

7834

60W

ilson

Run

at P

enfie

ld, P

a.19

62-1

995

338.

41,

770

00

.08

0154

2810

C41

3444

7817

34W

aldy

Run

nea

r Em

poriu

m, P

a.19

64-2

005

425.

241,

850

00

001

5430

00C

4124

4878

1150

Drif

twoo

d B

r Sin

nem

ahon

ing

Cr a

t Ste

rling

Run

, Pa.

1914

-200

592

272

1,74

00

.12

.62

0154

3500

C41

1902

7806

12Si

nnem

ahon

ing

Cre

ek a

t Sin

nem

ahon

ing,

Pa.

1936

-200

570

685

1,72

00

.14

.42

0154

3700

P41

3108

7801

40Fi

rst F

ork

Sinn

emah

onin

g C

reek

at W

harto

n, P

a.19

84-2

005

2218

21,

900

0.2

2.2

701

5444

50P

4138

4977

3922

Ger

man

ia B

ranc

h at

Ger

man

ia, P

a.19

64-1

979

112.

392,

150

0.0

1.0

601

5445

00C

4128

3377

4934

Ket

tle C

reek

at C

ross

For

k, P

a.19

36-2

005

6513

61,

890

0.3

2.0

501

5456

00C

4123

2277

4128

Youn

g W

oman

s Cre

ek n

ear R

enov

o, P

a.19

65-2

005

4146

.21,

820

0.0

1.1

101

5460

00C

4056

3077

4740

Nor

th B

ald

Eagl

e C

reek

at M

ilesb

urg,

Pa.

1911

-193

418

119

1,40

07.

47.3

2.7

201

5464

00C

4050

0177

4940

Sprin

g C

reek

at H

ouse

rvill

e, P

a.19

85-2

005

2158

.51,

340

75.1

.13

11.1

0154

6500

C40

5323

7747

40Sp

ring

Cre

ek n

ear A

xem

ann,

Pa.

1936

-200

566

87.2

1,28

083

.1.1

111

.501

5471

00C

4055

5477

4713

Sprin

g C

reek

at M

ilesb

urg,

Pa.

1967

-200

539

142

1,26

078

.3.1

59.

201

5472

00C

4056

3577

4712

Bal

d Ea

gle

Cre

ek b

l Spr

ing

Cre

ek a

t Mile

sbur

g, P

a.19

56-2

005

5026

51,

320

46.2

25.

4501

5475

00C

4103

0677

3617

Bal

d Ea

gle

Cre

ek a

t Bla

ncha

rd, P

a.19

55-2

005

1533

91,

250

44.6

1.99

4.89

0154

7700

C41

0334

7736

22M

arsh

Cre

ek a

t Bla

ncha

rd, P

a.19

56-2

005

5044

.11,

300

.35

.05

.53

0154

7800

C41

0126

7754

15So

uth

Fork

Bee

ch C

reek

nea

r Sno

w S

hoe,

Pa.

1959

-198

123

12.2

1,96

00

.01

2.6


ppen

dix

1.

Stre

amflo

w-g

agin

g st

atio

ns a

nd b

asin

cha

ract

eris

tics

used

in d

evel

opm

ent o

f flo

od-fl

ow re

gres

sion

equ

atio

ns fo

r Pen

nsyl

vani

a st

ream

s.—

Cont

inue

d

[C, c

ontin

uous

-rec

ord

stat

ion;

P, p

artia

l-rec

ord

stat

ion;

ddm

mss

, deg

rees

, min

utes

, sec

onds

; mi²,

squa

re m

iles;

ft, f

eet;

--, n

ot u

sed

in re

gres

sion

ana

lysi

s]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-

gagi

ng s

tatio

n nu

mbe

r

Type

Latit

ude

(ddm

mss

)Lo

ngitu

de

(ddm

mss

)St

atio

n na

me

Peri

od o

f re

cord

1 (w

ater

ye

ar)2

Num

ber o

f ye

ars

used

in

ana

lysi

s3

Bas

in c

hara

cter

istic

s

Dra

inag

e ar

ea

(mi2 )

Mea

n el

evat

ion

(ft)

Perc

ent

carb

on-

ate

bedr

ock

Perc

ent

stor

age

Perc

ent

urba

n ar

ea

0154

7950

C41

0642

7742

09B

eech

Cre

ek a

t Mon

umen

t, Pa

.19

68-2

005

3815

21,

670

00.

080.

7201

5480

05P

4104

5177

3259

Bal

d Ea

gle

Cre

ek n

ear B

eech

Cre

ek S

tatio

n, P

a.19

11-2

005

9456

21,

360

27.4

1.24

3.24

0154

8020

P41

0030

7719

35B

ull R

un n

ear L

ogan

ton,

Pa.

1963

-198

119

1.92

1,81

0.7

30

001

5485

00C

4131

1877

2652

Pine

Cre

ek a

t Ced

ar R

un, P

a.19

19-2

005

8760

41,

880

0.2

1.4

501

5490

00C

4118

4577

2245

Pine

Cre

ek n

ear W

ater

ville

, Pa.

1909

-192

012

750

1,83

00

.22

.38

0154

9500

C41

2825

7713

52B

lock

hous

e C

reek

nea

r Eng

lish

Cen

ter,

Pa.

1936

-200

565

37.7

1,77

00

.15

.81

0154

9700

C41

1625

7719

28Pi

ne C

reek

bl L

Pin

e C

reek

nea

r Wat

ervi

lle, P

a.19

58-2

005

4894

41,

790

0.2

9.3

801

5497

80C

4125

0477

0946

Larr

ys C

reek

at C

ogan

Hou

se, P

a.19

60-1

978

196.

81,

610

0.0

3.2

501

5500

00C

4125

0677

0159

Lyco

min

g C

reek

nea

r Tro

ut R

un, P

a.19

14-2

005

9217

31,

730

0.1

6.2

201

5505

00P

4116

0177

0249

Lyco

min

g C

reek

nea

r Will

iam

spor

t, Pa

.19

88-2

005

1426

41,

570

0.2

0.8

401

5510

00C

4115

1577

0040

Gra

fius R

un a

t Will

iam

spor

t, Pa

.19

40-1

953

143.

0390

80

.16

5.46

0155

2000

C41

1930

7654

46Lo

yals

ock

Cre

ek a

t Loy

also

ckvi

lle, P

a.19

26-2

005

8043

51,

670

0.8

0.3

301

5521

00P

4120

1076

5745

Mill

Cre

ek n

ear W

arre

nsvi

lle, P

a.19

61-1

978

1811

.91,

380

05.

30.2

201

5525

00C

4121

2576

3206

Mun

cy C

reek

nea

r Son

esto

wn,

Pa.

1936

-200

565

23.8

1,85

00

.21

.19

0155

3005

P41

1227

7645

09M

uncy

Cre

ek n

ear M

uncy

, Pa.

1989

-200

517

196

1,24

00

.43

.601

5530

50P

4107

0577

0400

Whi

te D

eer H

ole

Cre

ek n

ear E

limsp

ort,

Pa.

1961

-199

533

19.2

1,53

00

.29

001

5531

30C

4103

3177

0437

Sand

Spr

ing

Run

nea

r Whi

te D

eer,

Pa.

1968

-198

114

4.93

1,60

00

02.

9501

5536

00C

4104

5776

3917

EB C

hilli

squa

que

Cre

ek n

ear W

ashi

ngto

nvill

e, P

a.19

60-1

978

199.

4879

90

.72

.07

0155

3700

C41

0342

7640

50C

hilli

squa

que

Cre

ek a

t Was

hing

tonv

ille,

Pa.

1980

-200

526

51.5

735

6.65

1.14

.23

0155

5000

C40

5200

7702

55Pe

nns C

reek

at P

enns

Cre

ek, P

a.19

30-2

005

7630

11,

390

241.

15.6

0155

5500

C40

3640

7654

44Ea

st M

ahan

tang

o C

reek

nea

r Dal

mat

ia, P

a.19

30-2

005

7616

291

50

.25

1.6

0155

5800

P40

2235

7825

55M

cDon

ald

Run

nea

r Eas

t Fre

edom

, Pa.

1959

-197

819

1.44

1,32

00

01.

6401

5560

00C

4027

4778

1200

Fran

ksto

wn

Br J

unia

ta R

iver

at W

illia

msb

urg,

Pa.

1889

-200

589

291

1,53

021

.31

7.55

0155

6400

P40

3347

7820

35Sa

ndy

Run

nea

r Bel

lwoo

d, P

a.19

62-1

981

205.

931,

610

9.15

019

.201

5565

00C

4037

4078

1738

Littl

e Ju

niat

a R

iver

at T

ipto

n, P

a.19

36-1

981

3693

.71,

730

5.13

.29

9.83

0155

7100

C40

4000

7815

00Sc

hell

Run

at T

yron

e, P

a.19

58-1

981

231.

711,

500

00

4.92

0155

7500

C40

4101

7814

02B

ald

Eagl

e C

reek

at T

yron

e, P

a.19

36-2

005

6644

.11,

630

5.04

.02

1.19

0155

8000

C40

3645

7808

27Li

ttle

Juni

ata

Riv

er a

t Spr

uce

Cre

ek, P

a.19

36-2

005

6722

01,

570

20.5

.18

5.51

0155

9000

C40

2905

7801

09Ju

niat

a R

iver

at H

untin

gdon

, Pa.

1896

-200

510

481

61,

420

32.6

.25

4.43

0155

9500

C40

3125

7758

15St

andi

ng S

tone

Cre

ek n

ear H

untin

gdon

, Pa.

1889

-195

829

128

1,21

05.

11.6

3.0

901

5597

00C

3958

4078

3708

Sulp

hur S

prin

gs C

reek

nea

r Man

ns C

hoic

e, P

a.19

62-1

978

175.

281,

690

1.73

.01

2.12

0155

9790

P40

0245

7831

45R

ayst

own

Bra

nch

Juni

ata

Riv

er a

t Wol

fsbu

rg, P

a.19

89-2

005

1313

11,

680

1.17

.75

1.11

0156

0000

C40

0418

7829

34D

unni

ng C

reek

at B

elde

n, P

a.19

36-2

005

7017

21,

590

4.27

.21

1.23

0156

1000

C39

5720

7815

15B

rush

Cre

ek a

t Gap

svill

e, P

a.19

30-1

958

2936

.51,

570

0.1

41.

1601

5620

00C

4012

5778

1556

Ray

stow

n B

ranc

h Ju

niat

a R

iver

at S

axto

n, P

a.18

89-2

005

9375

61,

500

14.2

.27

1.71

Appendix 1 25A

ppen

dix

1.

Stre

amflo

w-g

agin

g st

atio

ns a

nd b

asin

cha

ract

eris

tics

used

in d

evel

opm

ent o

f flo

od-fl

ow re

gres

sion

equ

atio

ns fo

r Pen

nsyl

vani

a st

ream

s.—

Cont

inue

d

[C, c

ontin

uous

-rec

ord

stat

ion;

P, p

artia

l-rec

ord

stat

ion;

ddm

mss

, deg

rees

, min

utes

, sec

onds

; mi²,

squa

re m

iles;

ft, f

eet;

--, n

ot u

sed

in re

gres

sion

ana

lysi

s]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-

gagi

ng s

tatio

n nu

mbe

r

Type

Latit

ude

(ddm

mss

)Lo

ngitu

de

(ddm

mss

)St

atio

n na

me

Peri

od o

f re

cord

1 (w

ater

ye

ar)2

Num

ber o

f ye

ars

used

in

ana

lysi

s3

Bas

in c

hara

cter

istic

s

Dra

inag

e ar

ea

(mi2 )

Mea

n el

evat

ion

(ft)

Perc

ent

carb

on-

ate

bedr

ock

Perc

ent

stor

age

Perc

ent

urba

n ar

ea

0156

2500

C40

2100

7807

50G

reat

Tro

ugh

Cre

ek n

ear M

arkl

esbu

rg, P

a.19

30-1

957

2884

.61,

490

00.

310.

501

5630

00C

4025

3578

0147

Ray

stow

n B

ranc

h Ju

niat

a R

iver

nea

r Hun

tingd

on, P

a.19

36-1

971

2695

61,

470

11.7

1.40

1.51

0156

3800

P40

0520

7802

55El

ders

Bra

nch

near

Hus

tont

own,

Pa.

1960

-197

819

3.44

1,17

00

.07

.04

0156

4500

C40

1245

7755

32A

ughw

ick

Cre

ek n

ear T

hree

Spr

ings

, Pa.

1939

-200

567

205

1,18

04.

46.4

4.8

201

5645

12P

4016

5577

5327

Aug

hwic

k C

reek

nea

r Shi

rleys

burg

, Pa.

1990

-200

516

296

1,17

07.

03.4

7.7

101

5650

00C

4039

1777

3460

Kis

haco

quill

as C

reek

at R

eeds

ville

, Pa.

1936

-200

551

164

1,22

024

.8.1

91.

401

5657

00C

4036

2077

1840

Littl

e Lo

st C

reek

at O

akla

nd M

ills,

Pa.

1960

-198

122

6.52

758

47.8

.50

1.77

0156

5920

P40

2115

7738

55Li

ck R

un n

ear E

ast W

ater

ford

, Pa.

1962

-198

120

8.34

1,02

09.

09.4

1.2

0156

6000

C40

3055

7725

10Tu

scar

ora

Cre

ek n

ear P

ort R

oyal

, Pa.

1889

-200

562

214

1,01

00

1.05

.101

5665

00C

4033

5577

0705

Coc

olam

us C

reek

nea

r Mill

erst

own,

Pa.

1930

-197

229

57.2

813

5.66

.73

.21

0156

7500

C40

2215

7724

09B

ixle

r Run

nea

r Loy

svill

e, P

a.19

54-2

005

5215

907

0.9

1.2

301

5680

00C

4019

2477

1009

Sher

man

Cre

ek a

t She

rman

s Dal

e, P

a.19

27-2

005

7620

71,

010

0.9

8.3

701

5685

00C

4027

3776

4506

Cla

rk C

reek

nea

r Car

sonv

ille,

Pa.

1938

-199

659

221,

050

04.

62.0

501

5693

40P

4007

4077

3250

New

burg

Run

at N

ewbu

rg, P

a.19

64-1

995

325.

4280

40

01.

9501

5698

00C

4014

0577

0823

Leto

rt Sp

ring

Run

nea

r Car

lisle

, Pa.

1976

-200

530

21.6

498

99.5

124

.701

5700

00C

4015

0877

0117

Con

odog

uine

t Cre

ek n

ear H

oges

tow

n, P

a.19

12-2

005

7347

075

438

.1.8

53.

9801

5710

00C

4018

3076

5100

Paxt

on C

reek

nea

r Pen

broo

k, P

a.19

40-1

998

3511

.245

730

.1.0

464

.201

5715

00C

4013

2976

5354

Yello

w B

reec

hes C

reek

nea

r Cam

p H

ill, P

a.19

10-2

005

6221

680

934

.21.

606.

2201

5718

20C

4034

5076

2418

Swat

ara

Cre

ek a

t Rav

ine,

Pa.

1996

-200

610

43.9

1,14

00

.67

3.41

0157

2000

C40

3215

7622

40Lo

wer

Litt

le S

wat

ara

Cre

ek a

t Pin

e G

rove

, Pa.

1920

-198

418

34.3

840

0.3

3.6

701

5720

25C

4031

5776

2409

Swat

ara

Cre

ek n

ear P

ine

Gro

ve, P

a.19

89-2

005

1611

693

80

.59

2.67

0157

2190

C40

2845

7631

52Sw

atar

a C

reek

nea

r Inw

ood,

Pa.

1989

-200

517

161

919

0.8

12.

4601

5729

00P

4024

2576

3315

Ree

ds C

reek

nea

r Ono

, Pa.

1962

-198

120

8.69

518

3.64

.29

9.58

0157

3000

C40

2409

7634

39Sw

atar

a C

reek

at H

arpe

r Tav

ern,

Pa.

1889

-200

587

337

754

1.32

1.05

2.92

0157

3160

C40

2034

7633

46Q

uitta

pahi

lla C

reek

nea

r Bel

legr

ove,

Pa.

1975

-199

319

74.2

527

75.6

.41

16.1

0157

3500

C40

2350

7642

35M

anad

a C

r at M

anad

a G

ap, P

a.19

38-1

958

2113

.580

30

.28

.83

0157

3560

C40

1754

7640

05Sw

atar

a C

reek

nea

r Her

shey

, Pa.

1975

-200

531

483

687

12.9

.92

4.99

0157

4000

C40

0456

7643

13W

est C

onew

ago

Cre

ek n

ear M

anch

este

r, Pa

.19

29-2

005

7751

062

56.

171.

453.

2301

5745

00C

3952

4376

5113

Cod

orus

Cre

ek a

t Spr

ing

Gro

ve, P

a.19

30-2

005

3675

.570

316

.83.

623.

7401

5748

00C

3948

5776

3759

EB C

odor

us C

reek

Trib

utar

y ne

ar W

inte

rsto

wn,

Pa.

1960

-197

516

5.23

901

0.3

7.4

701

5750

00C

3955

1476

4457

Sout

h B

ranc

h C

odor

us C

reek

nea

r Yor

k, P

a.19

28-1

995

4311

774

71.

97.9

02.

9101

5760

85C

4008

4175

5920

Littl

e C

ones

toga

Cre

ek n

ear C

hurc

htow

n, P

a.19

82-1

995

145.

8262

551

.01

1.31

0157

6320

P40

1244

7607

30St

ony

Run

at R

eam

stow

n, P

a.19

64-1

995

313.

5652

310

.90

20.4

0157

6500

C40

0300

7616

39C

ones

toga

Riv

er a

t Lan

cast

er, P

a.19

29-2

005

7732

251

844

.31.

038.

0201

5767

54C

3956

4776

2205

Con

esto

ga R

iver

at C

ones

toga

, Pa.

1985

-200

520

470

479

59.7

811

.6


ppen

dix

1.

Stre

amflo

w-g

agin

g st

atio

ns a

nd b

asin

cha

ract

eris

tics

used

in d

evel

opm

ent o

f flo

od-fl

ow re

gres

sion

equ

atio

ns fo

r Pen

nsyl

vani

a st

ream

s.—

Cont

inue

d

[C, c

ontin

uous

-rec

ord

stat

ion;

P, p

artia

l-rec

ord

stat

ion;

ddm

mss

, deg

rees

, min

utes

, sec

onds

; mi²,

squa

re m

iles;

ft, f

eet;

--, n

ot u

sed

in re

gres

sion

ana

lysi

s]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-

gagi

ng s

tatio

n nu

mbe

r

Type

Latit

ude

(ddm

mss

)Lo

ngitu

de

(ddm

mss

)St

atio

n na

me

Peri

od o

f re

cord

1 (w

ater

ye

ar)2

Num

ber o

f ye

ars

used

in

ana

lysi

s3

Bas

in c

hara

cter

istic

s

Dra

inag

e ar

ea

(mi2 )

Mea

n el

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ion

(ft)

Perc

ent

carb

on-

ate

bedr

ock

Perc

ent

stor

age

Perc

ent

urba

n ar

ea

0157

7500

C39

4621

7618

58M

uddy

Cre

ek a

t Cas

tle F

in, P

a.19

29-1

972

1513

365

00.

330.

460.

701

5782

00P

3950

3576

1145

Con

owin

go C

reek

nea

r Buc

k, P

a.19

63-2

005

415.

5365

60

1.28

1.46

0157

8400

C39

5341

7606

50B

ower

y R

un n

ear Q

uarr

yvill

e, P

a.19

63-1

981

195.

9865

525

.4.9

8.0

201

6007

00P

3955

3578

3940

Littl

e W

ills C

reek

at B

ard,

Pa.

1961

-198

121

10.3

1,83

00

.02

.04

0160

1000

C39

4843

7843

00W

ills C

reek

bel

ow H

yndm

an, P

a.19

52-2

005

3814

62,

030

.96

.14

.33

0160

1500

C39

4007

7847

18W

ills C

reek

nea

r Cum

berla

nd, M

d.19

30-1

990

6124

7--

--.0

3--

0160

3500

C39

4723

7838

48Ev

itts C

reek

nea

r Cen

terv

ille,

Pa.

1933

-198

250

30.2

1,62

021

.8.2

2.2

0161

3050

C39

5354

7807

57To

nolo

way

Cre

ek n

ear N

eedm

ore,

Pa.

1963

-200

541

10.7

1,24

00

.14

.91

0161

3500

C39

4323

7803

38Li

ckin

g C

reek

nea

r Syl

van,

Pa.

1931

-194

111

158

1,04

016

.2.7

1.7

201

6140

90C

3955

4877

2623

Con

ococ

heag

ue C

reek

nea

r Fay

ette

ville

, Pa.

1961

-198

121

5.05

1,55

00

.55

001

6145

00C

3942

5777

4928

Con

ococ

heag

ue C

reek

at F

airv

iew,

Md.

1889

-199

064

494

--42

1.35

--01

6389

00P

3947

4577

1150

Whi

te R

un n

ear G

etty

sbur

g, P

a.19

61-1

980

2012

.555

30

2.31

8.64

0300

7800

C41

4907

7817

35A

llegh

eny

Riv

er a

t Por

t Alle

gany

, Pa.

1975

-200

531

248

2,06

00

.09

.94

0300

8000

C41

5340

7820

57N

ewel

l Cre

ek n

ear P

ort A

llega

ny, P

a.19

60-1

978

197.

791,

840

00

.103

0096

80C

4148

3578

2550

Pota

to C

reek

at S

met

hpor

t, Pa

.19

72-1

997

2416

01,

980

0.4

2.8

0301

0500

C41

5748

7823

11A

llegh

eny

Riv

er a

t Eld

red,

Pa.

1916

-200

590

550

1,98

00

1.45

.86

0301

0655

C41

5742

7811

54O

sway

o C

reek

at S

hing

leho

use,

Pa.

1975

-200

531

98.7

2,03

00

.13

.22

0301

1020

C42

0923

7842

56A

llegh

eny

Riv

er a

t Sal

aman

ca, N

.Y.

1904

-199

996

1,61

0--

--1.

040

0301

1800

C41

4559

7843

08K

inzu

a C

reek

nea

r Guf

fey,

Pa.

1966

-200

540

38.8

2,05

00

.64

1.09

0301

3000

C42

1015

7904

10C

onew

ango

Cre

ek a

t Wat

erbo

ro, N

.Y.

1938

-199

456

290

----

4.69

--03

0150

00C

4156

1779

0760

Con

ewan

go C

reek

at R

usse

ll, P

a.19

36-2

005

7081

61,

520

06.

452.

5703

0150

80P

4155

5579

0538

Ack

ley

Run

nea

r Rus

sell,

Pa.

1962

-198

120

9.65

1,90

00

0.1

603

0152

80C

4154

1079

1418

Jack

son

Run

nea

r Nor

th W

arre

n, P

a.19

63-1

979

1712

.81,

650

02.

33.9

0301

5390

P41

5629

7938

41H

are

Cre

ek n

ear C

orry

, Pa.

1964

-198

519

13.6

1,63

00

3.41

.26

0301

5500

C41

5109

7919

03B

roke

nstra

w C

reek

at Y

oung

svill

e, P

a.19

10-2

005

9632

11,

600

02.

961.

0803

0175

00C

4136

0779

0301

Tion

esta

Cre

ek a

t Lyn

ch, P

a.19

38-1

979

4223

31,

760

0.1

11.

2903

0190

00C

4128

2579

2305

Tion

esta

Cre

ek a

t Neb

rask

a, P

a.19

10-1

940

1946

91,

690

0.5

8.8

203

0204

40P

4145

3179

3408

WB

Cal

dwel

l Cre

ek n

ear G

rand

Val

ley,

Pa.

1964

-198

116

4.37

1,68

00

0.0

803

0205

00C

4128

5479

4144

Oil

Cre

ek a

t Rou

sevi

lle, P

a.19

10-2

005

9630

01,

520

01.

321.

1703

0213

50C

4200

5579

4658

Fren

ch C

reek

nea

r Wat

tsbu

rg, P

a.19

75-2

005

3192

1,60

00

2.48

.503

0214

10C

4204

5479

5102

Wes

t Bra

nch

Fren

ch C

reek

nea

r Low

ville

, Pa.

1975

-199

420

52.3

1,47

00

5.25

1.12

0302

1700

C41

5553

8005

02Li

ttle

Con

neau

ttee

Cre

ek n

ear M

cKea

n, P

a.19

61-1

978

183.

61,

440

00

.01

0302

2500

C41

4250

8008

50Fr

ench

Cre

ek a

t Sae

gers

tow

n, P

a.19

13-1

939

1862

91,

420

04.

541.

3903

0225

40C

4141

2680

0254

Woo

dcoc

k C

reek

at B

loom

ing

Valle

y, P

a.19

75-2

005

3131

.11,

450

02.

03.1

803

0230

00C

4140

2080

1255

Cus

sew

ago

Cre

ek n

ear M

eadv

ille,

Pa.

1911

-193

828

90.2

1,25

00

7.31

2.07

Appendix 1 27A

ppen

dix

1.

Stre

amflo

w-g

agin

g st

atio

ns a

nd b

asin

cha

ract

eris

tics

used

in d

evel

opm

ent o

f flo

od-fl

ow re

gres

sion

equ

atio

ns fo

r Pen

nsyl

vani

a st

ream

s.—

Cont

inue

d

[C, c

ontin

uous

-rec

ord

stat

ion;

P, p

artia

l-rec

ord

stat

ion;

ddm

mss

, deg

rees

, min

utes

, sec

onds

; mi²,

squa

re m

iles;

ft, f

eet;

--, n

ot u

sed

in re

gres

sion

ana

lysi

s]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-

gagi

ng s

tatio

n nu

mbe

r

Type

Latit

ude

(ddm

mss

)Lo

ngitu

de

(ddm

mss

)St

atio

n na

me

Peri

od o

f re

cord

1 (w

ater

ye

ar)2

Num

ber o

f ye

ars

used

in

ana

lysi

s3

Bas

in c

hara

cter

istic

s

Dra

inag

e ar

ea

(mi2 )

Mea

n el

evat

ion

(ft)

Perc

ent

carb

on-

ate

bedr

ock

Perc

ent

stor

age

Perc

ent

urba

n ar

ea

0302

3500

C41

2815

8001

05Fr

ench

Cre

ek a

t Car

lton,

Pa.

1909

-192

517

998

1,37

00

5.43

2.4

0302

4000

C41

2615

7957

22Fr

ench

Cre

ek a

t Utic

a, P

a.19

13-2

005

381,

030

1,37

00

5.29

2.33

0302

5000

C41

2543

7952

48Su

gar C

reek

at S

ugar

cree

k, P

a.19

33-1

979

4716

61,

440

01.

90.3

103

0252

00C

4125

2079

5059

Patc

hel R

un n

ear F

rank

lin, P

a.19

61-1

978

185.

671,

400

00

.81

0302

6400

P41

1053

7941

25R

iche

y R

un a

t Em

lent

on, P

a.19

63-1

981

195.

691,

390

00

3.18

0302

6500

C41

3752

7834

37Se

venm

ile R

un n

ear R

asse

las,

Pa.

1952

-200

554

7.84

2,07

00

0.1

603

0280

00C

4134

3178

4133

Wes

t Bra

nch

Cla

rion

Riv

er a

t Wilc

ox, P

a.19

55-2

005

5163

1,96

00

.18

1.17

0302

9000

C41

2515

7844

10C

lario

n R

iver

at R

idgw

ay, P

a.19

41-2

004

1230

31,

910

0.9

32.

7103

0292

00P

4119

1779

0439

Cle

ar C

reek

nea

r Sig

el, P

a.19

60-1

981

217.

321,

750

00

.03

0302

9400

C41

2016

7912

50To

ms R

un a

t Coo

ksbu

rg, P

a.19

60-1

978

1912

.61,

570

0.1

71

0302

9500

C41

1950

7912

33C

lario

n R

iver

at C

ooks

burg

, Pa.

1936

-200

567

807

1,78

00

.49

1.38

0303

0500

C41

1133

7926

25C

lario

n R

iver

nea

r Pin

ey, P

a.19

36-2

005

5896

61,

740

0.4

11.

4603

0310

00C

4108

5779

3937

Cla

rion

Riv

er a

t St.

Pete

rsbu

rg, P

a.19

42-1

953

121,

240

1,66

00

.32

1.58

0303

1780

P41

1453

7850

08M

ill C

reek

nea

r Bro

ckw

ay, P

a.19

65-1

981

172.

021,

760

0.1

2.1

203

0319

50C

4059

3079

0526

Big

Run

nr S

pran

kle

Mill

s, Pa

.19

64-1

981

187.

381,

510

00

.503

0325

00C

4059

4079

2340

Red

bank

Cre

ek a

t St.

Cha

rles,

Pa.

1910

-200

596

528

1,56

00

.72

2.79

0303

4000

C40

5621

7900

31M

ahon

ing

Cre

ek a

t Pun

xsut

awne

y, P

a.19

36-2

005

7015

81,

580

0.2

33.

0303

0345

00C

4050

1079

0637

Littl

e M

ahon

ing

Cre

ek a

t McC

orm

ick,

Pa.

1940

-200

566

87.4

1,56

00

0.3

503

0350

00C

4054

0579

1335

Mah

onin

g C

reek

nea

r Day

ton,

Pa.

1917

-194

024

321

1,53

00

1.03

1.79

0303

8000

C40

3917

7920

56C

rook

ed C

reek

at I

daho

, Pa.

1936

-200

570

191

1,27

00

.81

1.21

0303

9000

C40

4313

7930

42C

rook

ed C

reek

at C

rook

ed C

reek

Dam

, Pa.

1910

-199

130

275

1,24

00

1.62

1.09

0303

9200

C40

0249

7849

58C

lear

Run

nea

r Buc

ksto

wn,

Pa.

1961

-197

818

3.68

2,70

00

.25

.36

0304

0000

C40

1708

7855

15St

onyc

reek

Riv

er a

t Fer

ndal

e, P

a.19

14-2

005

9045

22,

160

01.

132.

9403

0410

00P

4020

3778

5307

Littl

e C

onem

augh

Riv

er a

t Eas

t Con

emau

gh, P

a.19

36-2

005

7018

62,

070

0.9

25.

2903

0415

00C

4025

0979

0135

Con

emau

gh R

iver

at S

ewar

d, P

a.19

36-2

005

7072

72,

090

0.9

75.

3503

0420

00C

4028

2479

1101

Bla

cklic

k C

reek

at J

osep

hine

, Pa.

1952

-200

554

192

1,81

00

.19

2.02

0304

2170

P40

3631

7909

49St

oney

Run

at I

ndia

na, P

a.19

64-1

977

134.

511,

340

00

67.1

0304

2200

C40

3345

7856

44Li

ttle Y

ello

w C

reek

nea

r Stro

ngst

own,

Pa.

1961

-198

719

7.36

1,84

00

0.1

903

0425

00C

4031

0279

1019

Two

Lick

Cre

ek a

t Gra

ceto

n, P

a.19

52-2

005

1717

11,

530

0.7

05.

2703

0430

00C

4028

2579

1215

Bla

cklic

k C

reek

at B

lack

Lic

k, P

a.19

05-1

951

4739

01,

650

0.5

73.

5403

0450

00C

4017

3379

2027

Loya

lhan

na C

reek

at K

ings

ton,

Pa.

1940

-200

566

172

1,72

00

.25

2.11

0304

5500

C40

2340

7925

55Lo

yalh

anna

Cre

ek a

t New

Ale

xand

ria, P

a.19

11-1

940

1926

51,

550

01.

084.

903

0475

00C

4032

0579

2755

Kis

kim

inet

as R

iver

at A

vonm

ore,

Pa.

1884

-193

748

1,72

01,

750

01.

424.

3303

0490

00C

4042

5779

4159

Buf

falo

Cre

ek n

ear F

reep

ort,

Pa.

1941

-200

564

137

1,25

00

.05

1.73

0304

9800

C40

3113

7956

18Li

ttle

Pine

Cre

ek n

ear E

tna,

Pa.

1963

-200

542

5.78

1,11

00

026


ppen

dix

1.

Stre

amflo

w-g

agin

g st

atio

ns a

nd b

asin

cha

ract

eris

tics

used

in d

evel

opm

ent o

f flo

od-fl

ow re

gres

sion

equ

atio

ns fo

r Pen

nsyl

vani

a st

ream

s.—

Cont

inue

d

[C, c

ontin

uous

-rec

ord

stat

ion;

P, p

artia

l-rec

ord

stat

ion;

ddm

mss

, deg

rees

, min

utes

, sec

onds

; mi²,

squa

re m

iles;

ft, f

eet;

--, n

ot u

sed

in re

gres

sion

ana

lysi

s]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-

gagi

ng s

tatio

n nu

mbe

r

Type

Latit

ude

(ddm

mss

)Lo

ngitu

de

(ddm

mss

)St

atio

n na

me

Peri

od o

f re

cord

1 (w

ater

ye

ar)2

Num

ber o

f ye

ars

used

in

ana

lysi

s3

Bas

in c

hara

cter

istic

s

Dra

inag

e ar

ea

(mi2 )

Mea

n el

evat

ion

(ft)

Perc

ent

carb

on-

ate

bedr

ock

Perc

ent

stor

age

Perc

ent

urba

n ar

ea

0306

2500

C39

3745

7957

10D

ecke

rs C

reek

at M

orga

ntow

n, W

.V.

1947

-199

751

63.2

1,77

0--

----

0307

0420

C39

4551

7935

14St

ony

Fork

Trib

utar

y ne

ar G

ibbo

n G

lade

, Pa.

1978

-198

912

.92

1,87

00

00.

1903

0705

00C

3937

1879

4218

Big

San

dy C

reek

nea

r Roc

kvill

e, W

.V.

1888

-199

711

020

02,

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----

--03

0720

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3945

3379

5815

Dun

kard

Cre

ek a

t Sha

nnop

in, P

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4.6

603

0725

90C

3947

4479

4747

Geo

rges

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ek a

t Sm

ithfie

ld, P

a.19

64-1

978

1516

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390

0.1

09.

4503

0728

40C

3959

5180

0231

Tenm

ile C

reek

nea

r Cla

rksv

ille,

Pa.

1969

-197

911

133

1,17

00

.06

3.29

0307

2880

P39

5627

8017

21B

row

ns C

reek

nea

r Nin

eveh

, Pa.

1963

-199

533

17.7

1,25

00

.03

.23

0307

3000

C39

5523

8004

22So

uth

Fork

Ten

mile

Cre

ek a

t Jef

fers

on, P

a.19

32-1

995

6418

01,

210

0.0

62.

2603

0743

00C

3952

0479

4140

Lick

Run

at H

opw

ood,

Pa.

1959

-197

820

3.8

1,99

00

0.8

0307

4500

C39

5848

7945

52R

edst

one

Cre

ek a

t Wal

ters

burg

, Pa.

1943

-200

563

73.7

1,28

00

.27

13.6

0307

8000

C39

4208

1908

12C

asse

lman

at G

rant

svill

e, M

d.19

48-1

990

4362

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--2.

39--

0307

8500

C39

4334

7902

55B

ig P

iney

Run

nea

r Sal

isbu

ry, P

a.19

33-1

970

3824

.52,

560

.45

1.12

.78

0307

9000

C39

5135

7913

40C

asse

lman

Riv

er a

t Mar

klet

on, P

a.19

15-2

005

9138

22,

360

.03

.81

2.09

0308

0000

C39

4913

7919

18La

urel

Hill

Cre

ek a

t Urs

ina,

Pa.

1914

-200

592

121

2,21

00

.65

.71

0308

2200

C40

0059

7925

33Po

plar

Run

nea

r Nor

mal

ville

, Pa.

1961

-197

818

9.27

1,94

00

0.2

303

0825

00C

4001

0379

3538

Youg

hiog

heny

Riv

er a

t Con

nells

ville

, Pa.

1860

-194

150

1,33

02,

260

21.

571.

6603

0830

00C

4006

1879

3001

Gre

en L

ick

Run

at G

reen

Lic

k R

eser

voir,

Pa.

1929

-197

951

3.11

1,91

00

0.0

603

0835

00C

4014

2479

4824

Youg

hiog

heny

Riv

er a

t Sut

ersv

ille,

Pa.

1921

-194

121

1,71

02,

020

1.54

1.27

3.56

0308

3600

P40

1359

7949

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illes

pie

Run

nea

r Sut

ersv

ille,

Pa.

1959

-198

121

4.05

1,12

00

011

.603

0840

00C

4027

0179

4250

Abe

rs C

reek

nea

r Mur

rysv

ille,

Pa.

1949

-199

345

4.39

1,16

00

.13

45.1

0308

4500

C40

2309

7945

55Tu

rtle

Cre

ek a

t Tra

fford

, Pa.

1917

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538

55.9

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00

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22.4

0308

5500

C40

2402

8005

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harti

ers C

reek

at C

arne

gie,

Pa.

1916

-200

582

257

1,13

00

.52

26.4

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6100

C40

3627

8009

49B

ig S

ewic

kley

Cre

ek n

ear A

mbr

idge

, Pa.

1963

-197

816

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1,09

00

013

.803

0987

00C

4107

2080

3808

Cra

b C

reek

at Y

oung

stow

n, O

hio

1959

-198

224

141,

060

--6.

6531

.803

1000

00C

4130

4580

2815

Shen

ango

Riv

er n

ear T

urne

rsvi

lle, P

a.19

12-1

922

1115

21,

090

022

.61

5.56

0310

1000

C41

2950

8027

55Su

gar R

un a

t Pym

atun

ing

Dam

, Pa.

1935

-195

521

8.59

1,12

00

.32

1.55

0310

2500

C41

2519

8022

35Li

ttle

Shen

ango

Riv

er a

t Gre

envi

lle, P

a.19

14-2

005

8910

41,

210

05.

832.

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1029

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4126

3480

3518

Pym

atun

ing

Cre

ek a

t Kin

sman

, Ohi

o19

66-2

001

3696

.71,

030

--12

.96

.32

0310

3000

C41

1840

8028

40Py

mat

unin

g C

reek

nea

r Ora

ngev

ille,

Pa.

1914

-196

348

169

1,05

00

12.5

3.6

503

1040

00C

4113

5580

3035

Shen

ango

Riv

er a

t Sha

ron,

Pa.

1912

-193

821

608

1,10

00

11.8

64.

603

1045

00C

4100

0080

2105

Shen

ango

Riv

er a

t New

Cas

tle, P

a.19

13-1

933

2079

81,

090

010

.27

7.11

0310

4760

C41

1110

8019

38H

arth

egig

Run

nea

r Gre

enfie

ld, P

a.19

69-1

980

122.

261,

260

04.

122.

0803

1060

00C

4049

0180

1433

Con

noqu

enes

sing

Cre

ek n

ear Z

elie

nopl

e, P

a.19

16-2

005

9035

61,

190

0.3

510

0310

6500

C40

5302

8014

02Sl

ippe

ry R

ock

Cre

ek a

t Wur

tem

burg

, Pa.

1912

-196

856

398

1,31

00

4.02

2.53

0310

8000

C40

3740

8020

16R

acco

on C

reek

at M

offa

tts M

ill, P

a.19

16-2

005

9017

81,

110

0.5

48.

55

Appendix 1 29A

ppen

dix

1.

Stre

amflo

w-g

agin

g st

atio

ns a

nd b

asin

cha

ract

eris

tics

used

in d

evel

opm

ent o

f flo

od-fl

ow re

gres

sion

equ

atio

ns fo

r Pen

nsyl

vani

a st

ream

s.—

Cont

inue

d

[C, c

ontin

uous

-rec

ord

stat

ion;

P, p

artia

l-rec

ord

stat

ion;

ddm

mss

, deg

rees

, min

utes

, sec

onds

; mi²,

squa

re m

iles;

ft, f

eet;

--, n

ot u

sed

in re

gres

sion

ana

lysi

s]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-

gagi

ng s

tatio

n nu

mbe

r

Type

Latit

ude

(ddm

mss

)Lo

ngitu

de

(ddm

mss

)St

atio

n na

me

Peri

od o

f re

cord

1 (w

ater

ye

ar)2

Num

ber o

f ye

ars

used

in

ana

lysi

s3

Bas

in c

hara

cter

istic

s

Dra

inag

e ar

ea

(mi2 )

Mea

n el

evat

ion

(ft)

Perc

ent

carb

on-

ate

bedr

ock

Perc

ent

stor

age

Perc

ent

urba

n ar

ea

0310

9000

C40

4655

8045

33Li

sbon

Cre

ek a

t Lis

bon,

Ohi

o19

47-1

981

356.

191,

180

--0.

401.

8503

1095

00C

4040

3380

3227

Littl

e B

eave

r Cre

ek n

ear E

ast L

iver

pool

, Ohi

o19

16-2

001

8649

61,

140

--.4

23.

6403

1111

50C

4011

5480

2428

Bru

sh R

un n

ear B

uffa

lo, P

a.19

61-1

985

2110

.31,

190

00

1.11

0421

3000

C41

5537

8036

15C

onne

aut C

reek

at C

onne

aut,

Ohi

o19

23-2

001

6617

51,

010

--2.

731.

7604

2130

40C

4156

4280

2651

Rac

coon

Cre

ek n

ear W

est S

prin

gfie

ld, P

a.19

61-1

995

342.

682

10

6.01

3.61

0421

3075

C41

5931

8017

29B

rand

y R

un n

ear G

irard

, Pa.

1987

-200

519

4.45

898

0.2

29.

104

2132

00P

4205

5480

0435

Mill

Cre

ek a

t Erie

, Pa.

1964

-200

542

9.16

1,05

00

035

.21 P

erio

d of

reco

rd m

ay in

clud

e hi

stor

ical

pea

ks, p

erio

ds o

f flo

w re

gula

tion,

and

bre

aks i

n sy

stem

atic

per

iod

of re

cord

. 2 W

ater

yea

r is d

efin

ed a

s a 1

2-m

onth

per

iod

begi

nnin

g O

ctob

er 1

and

end

ing

Sept

embe

r 30.

The

wat

er y

ear i

s des

igna

ted

by th

e ca

lend

ar y

ear i

n w

hich

it e

nds.

3 Num

ber o

f yea

rs u

sed

in a

naly

sis p

rimar

ily c

onsi

sts o

f the

syst

emat

ic p

erio

d of

reco

rd a

nd m

ay in

clud

e hi

stor

ic p

eak

year

. Bre

aks i

n sy

stem

atic

per

iod

of re

cord

and

flow

-reg

ulat

ed y

ears

are

not

incl

uded

.

30 Regression Equations for Estimating Flood Flows for Selected Recurrence Intervals

Appendix 2. Flood-flow magnitudes for selected recurrence intervals computed from observed streamflow-gaging station data, predicted from regional regression equations, and a weighted average for streamflow-gaging stations used in analysis.—Continued

U.S. Geological Survey

streamflow-gaging station

number

Flood-flow region

Type

Flood-flow estimates, in cubic feet per second

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

01424500 1 Observed 2,120 2,950 3,520 4,880 5,500 7,040Predicted 1,780 2,990 3,960 6,570 7,890 11,500

Weighted 2,080 2,960 3,640 5,480 6,380 8,730


Weighted 2,760 4,110 5,130 7,770 9,030 12,300


Weighted 2,010 3,520 4,930 9,630 12,600 22,900


Weighted 2,660 3,760 4,630 7,040 8,270 11,600


Weighted 1,990 3,060 3,940 6,350 7,590 11,100


Weighted 3,250 5,420 7,250 12,800 16,100 26,600


Weighted 6,260 9,230 11,700 18,500 22,200 32,600


Weighted 5,740 8,870 11,500 18,700 22,300 32,700


Weighted 2,420 4,010 5,270 8,710 10,500 15,300


Weighted 8,380 14,000 19,000 34,700 43,900 73,400

01431680 1 Observed 226 314 377 532 605 794Predicted 234 415 562 960 1,160 1,730

Weighted 227 337 432 697 828 1,180

01438300 1 Observed 166 258 331 528 628 908Predicted 274 485 655 1,110 1,330 1,960

Weighted 173 285 383 654 790 1,160


Weighted 2,010 3,350 4,590 8,520 10,800 18,200

Appendix 2 31




number

Flood-flow region

Type



01440300 1 Observed 370 682 943 1,680 2,070 3,160

Predicted 304 536 723 1,220 1,480 2,170

Weighted 366 665 909 1,580 1,940 2,930


Weighted 2,860 5,000 6,720 11,400 13,900 20,800


Weighted 1,590 2,470 3,200 5,120 6,050 8,410


Weighted 8,810 15,300 21,200 40,000 51,200 88,000

01446600 1 Observed 459 811 1,130 2,120 2,700 4,520Predicted 401 699 945 1,620 1,960 2,920

Weighted 453 790 1,080 1,960 2,450 3,960


Weighted 2,400 4,730 6,970 14,700 19,600 36,500

01447680 1 Observed 346 530 670 1,020 1,200 1,650

Predicted 528 906 1,230 2,130 2,610 3,970

Weighted 360 580 768 1,290 1,550 2,250


Weighted 3,090 5,570 7,590 13,200 16,200 24,700

01448000 1 Observed 6,500 11,800 17,100 35,300 47,000 87,600

Predicted 6,700 10,800 14,200 23,600 28,400 42,000

Weighted 6,510 11,700 16,600 32,800 42,700 76,800

01448500 1 Observed 137 249 345 626 779 1,230Predicted 121 217 297 514 625 936

Weighted 136 246 339 606 750 1,170


Weighted 11,900 18,100 23,000 35,900 42,200 59,100


Weighted 1,140 1,800 2,340 3,720 4,370 6,000

01449500 1 Observed 536 1,090 1,620 3,390 4,470 7,990Predicted 639 1,100 1,480 2,500 3,020 4,480

Weighted 552 1,090 1,570 3,030 3,850 6,460





number

Flood-flow region

Type




Weighted 1,960 3,380 4,610 7,920 9,550 13,900

01450500 1 Observed 2,270 3,910 5,310 9,450 11,700 18,500

Predicted 2,780 4,630 6,100 10,000 12,000 17,300

Weighted 2,290 3,970 5,400 9,540 11,800 18,300


Weighted 21,300 34,500 45,300 76,000 92,700 143,000


Weighted 1,620 3,730 5,830 12,900 17,200 31,500


Weighted 2,380 5,030 7,520 15,500 20,200 36,200


Weighted 2,300 3,840 5,040 8,180 9,750 14,000


Weighted 2,930 5,190 7,100 12,600 15,500 24,000

01452300 1 Observed 270 508 707 1,270 1,560 2,370

Predicted 290 513 692 1,170 1,410 2,080

Weighted 273 509 702 1,230 1,500 2,250

01452500 1 Observed 596 1,250 1,920 4,440 6,120 12,200Predicted 1,770 2,980 3,940 6,500 7,780 11,300

Weighted 654 1,400 2,160 4,780 6,410 12,000


Weighted 22,400 37,700 50,700 88,200 108,000 168,000


Weighted 110 207 296 579 748 1,312


Weighted 6,210 8,960 11,000 16,200 18,900 26,300


Weighted 10,700 16,900 21,800 35,100 42,000 61,900

Appendix 2 33




number

Flood-flow region

Type




Weighted 758 1,120 1,420 2,260 2,670 3,750


Weighted 639 876 1,060 1,560 1,810 2,510


Weighted 814 1,190 1,510 2,390 2,820 3,960


Weighted 3,070 4,460 5,470 7,970 9,190 12,500


Weighted 2,670 3,830 4,770 7,270 8,440 11,300

01467043 2 Observed 280 471 622 1,030 1,230 1,790Predicted 586 903 1,150 1,770 2,070 2,840

Weighted 314 564 783 1,360 1,640 2,320


Weighted 3,710 5,740 7,360 11,700 13,900 20,000

01467050 2 Observed 879 1,320 1,660 2,570 3,030 4,320Predicted 594 959 1,250 2,000 2,370 3,340

Weighted 849 1,240 1,540 2,320 2,720 3,840


Weighted 2,340 3,300 3,970 5,610 6,370 8,300


Weighted 6,030 8,060 9,290 12,100 13,400 17,000


Weighted 6,280 7,680 8,510 10,600 11,700 14,600


Weighted 3,450 5,700 7,620 13,100 15,900 24,100


Weighted 1,400 2,430 3,230 5,260 6,230 8,740





number

Flood-flow region

Type




Weighted 11,500 18,300 23,500 36,700 43,100 60,000


Weighted 454 853 1,190 2,170 2,710 4,370


Weighted 4,840 7,700 10,100 17,100 20,700 31,200


Weighted 2,000 3,900 5,530 10,100 12,500 19,500

01470853 1 Observed 210 403 558 972 1,170 1,710Predicted 307 542 731 1,230 1,480 2,180

Weighted 222 432 605 1,060 1,290 1,880


Weighted 4,360 8,150 11,300 20,200 24,900 38,500


Weighted 5,090 7,980 10,400 17,000 20,400 29,300


Weighted 19,700 30,100 38,600 61,700 73,200 105,000


Weighted 2,640 3,730 4,650 7,360 8,750 12,400


Weighted 3,420 5,150 6,450 9,880 11,600 16,000


Weighted 20,800 31,800 40,400 63,200 74,700 106,000


Weighted 2,490 4,580 6,440 12,000 15,000 24,100


Weighted 635 1,270 1,810 3,350 4,180 6,660

Appendix 2 35




number

Flood-flow region

Type




Weighted 2,640 4,360 5,650 9,060 10,800 15,500


Weighted 1,450 2,190 2,780 4,480 5,340 7,610


Weighted 838 1,320 1,670 2,590 3,070 4,430


Weighted 14,900 22,800 28,000 39,700 44,800 57,200

01473100 2 Observed 2,080 3,690 5,110 9,410 11,800 19,200Predicted 695 1,270 1,750 3,100 3,800 5,830

Weighted 1,960 3,270 4,270 6,990 8,500 13,300


Weighted 5,590 8,880 11,700 20,200 25,300 42,100


Weighted 1,270 2,060 2,730 4,550 5,510 8,400

01473880 2 Observed 239 372 473 732 858 1,190Predicted 407 674 889 1,450 1,730 2,470

Weighted 256 431 590 1,030 1,250 1,800


Weighted 3,290 5,040 6,480 10,500 12,700 19,100


Weighted 3,220 4,560 5,640 8,460 9,800 13,200


Weighted 3,720 5,910 7,850 13,700 16,900 27,400


Weighted 684 1,120 1,460 2,370 2,810 3,960

01475510 2 Observed 2,880 4,050 4,880 6,850 7,740 9,990

Predicted 3,330 4,870 6,070 9,090 10,500 14,100

Weighted 2,910 4,170 5,130 7,580 8,730 11,600





number

Flood-flow region

Type




Weighted 816 1,500 2,090 3,810 4,770 7,930


Weighted 2,470 3,530 4,300 6,210 7,100 9,330


Weighted 1,160 1,990 2,690 4,680 5,710 8,600


Weighted 1,540 3,150 4,650 9,260 11,900 20,600


Weighted 1,270 2,350 3,420 6,750 8,600 14,400


Weighted 3,010 5,360 7,490 14,100 18,000 30,100


Weighted 970 1,680 2,290 4,050 5,000 7,750


Weighted 1,930 3,980 5,950 12,600 16,900 33,400


Weighted 1,230 2,200 3,030 5,420 6,700 10,400


Weighted 1,930 3,510 4,910 9,050 11,300 17,900

01480610 2 Observed 331 588 802 1,410 1,730 2,650Predicted 336 587 792 1,350 1,630 2,420

Weighted 331 588 800 1,390 1,700 2,580


Weighted 2,600 4,630 6,300 10,900 13,200 19,900


Weighted 3,570 4,740 5,980 9,830 11,800 16,900

Appendix 2 37




number

Flood-flow region

Type




Weighted 7,050 11,200 14,600 23,900 28,600 41,500


Weighted 5,960 9,080 11,500 18,100 21,300 29,800


Weighted 6,9890 12,500 17,200 31,700 40,100 86,900


Weighted 797 1,430 1,990 3,710 4,700 7,840

01516800 1 Observed 318 463 563 793 895 1,140Predicted 172 308 419 714 863 1,270

Weighted 295 422 515 759 881 1,200


Weighted 588 1,010 1,380 2,490 3,130 5,120


Weighted 10,100 17,900 24,500 44,600 55,900 91,300


Weighted 4,300 6,880 8,900 14,500 17,500 26,200


Weighted 3,840 6,490 8,790 15,500 19,100 30,000


Weighted 4,110 6,880 8,880 13,900 16,200 22,500


Weighted 9,720 15,000 18,900 28,800 33,700 46,600


Weighted 10,500 17,400 23,100 39,200 47,800 73,400


Weighted 6,190 9,800 12,300 18,200 20,900 27,600





number

Flood-flow region

Type




Weighted 9,790 17,200 23,500 42,500 53,200 86,200


Weighted 643 1,040 1,390 2,420 2,970 4,620


Weighted 396 700 936 1,570 1,890 2,770

01533250 1 Observed 470 799 1,060 1,720 2,050 2,910Predicted 539 936 1,260 2,110 2,540 3,730

Weighted 476 820 1,100 1,830 2,190 3,150


Weighted 410 735 1,020 1,890 2,390 4,000


Weighted 734 1,130 1,440 2,230 2,630 3,690


Weighted 13,100 19,900 24,600 35,500 40,300 52,200


Weighted 3,280 4,950 6,380 10,400 12,400 18,000


Weighted 8,400 13,100 17,100 28,500 34,500 51,500


Weighted 1,220 2,030 2,690 4,480 5,380 7,860


Weighted 405 701 925 1,520 1,820 2,660


Weighted 8,630 14,300 18,800 31,100 37,300 54,700


Weighted 2,100 2,990 3,740 5,770 6,740 9,230

Appendix 2 39




number

Flood-flow region

Type




Weighted 11,400 17,800 22,500 34,300 40,000 54,600


Weighted 60 137 215 464 613 1,110


Weighted 7,780 11,400 14,100 21,300 24,900 34,800


Weighted 9,160 12,500 14,800 20,300 22,800 28,700


Weighted 7,820 11,200 13,600 19,500 22,200 29,000


Weighted 1,310 2,050 2,630 4,090 4,760 6,490


Weighted 27,400 38,000 45,100 61,200 68,200 85,000


Weighted 249 368 466 717 829 1,100

01542810 3 Observed 192 301 390 643 777 1,170Predicted 245 412 542 867 1,020 1,440

Weighted 195 313 413 688 828 1,220


Weighted 8,100 13,400 17,700 30,000 36,500 55,800


Weighted 16,900 26,700 34,500 55,800 67,100 99,600


Weighted 4,540 6,900 8,710 13,300 15,600 21,800

01544450 3 Observed 100 140 167 234 264 340Predicted 109 181 235 372 436 606

Weighted 102 153 194 301 350 473





number

Flood-flow region

Type




Weighted 3,510 5,750 7,590 12,800 15,600 23,800


Weighted 927 1,730 2,470 4,720 6,000 10,100


Weighted 6,410 9,140 11,100 16,200 19,000 26,700

01546400 3 Observed 568 939 1,260 2,270 2,840 4,630Predicted 681 1,210 1,660 2,880 3,500 5,250

Weighted 581 992 1,370 2,470 3,070 4,840


Weighted 715 1,340 1,970 4,140 5,520 10,400


Weighted 1,240 2,290 3,270 6,420 8,290 14,500


Weighted 4,950 8,100 10,700 18,100 22,100 34,100


Weighted 4,220 6,170 7,650 11,400 13,100 17,600


Weighted 1,230 2,250 3,190 6,190 7,970 13,900


Weighted 333 567 766 1,310 1,580 2,330


Weighted 2,520 4,200 5,600 9,290 11,100 16,100


Weighted 8,010 12,400 15,700 23,600 27,300 36,900


Weighted 67 128 184 347 433 695

Appendix 2 41




number

Flood-flow region

Type




Weighted 12,200 20,000 26,600 45,600 55,800 85,300


Weighted 21,100 30,500 37,800 56,600 65,500 88,400


Weighted 1,810 2,950 3,860 6,330 7,600 11,100


Weighted 19,700 32,400 43,000 72,600 88,000 132,000


Weighted 265 474 662 1,200 1,480 2,290


Weighted 6,620 10,700 14,000 23,000 27,700 40,900


Weighted 9,550 16,700 22,700 40,300 50,300 82,100

01551000 1 Observed 273 515 711 1,240 1,500 2,190Predicted 180 322 437 741 895 1,320

Weighted 256 457 607 1,000 1,200 1,750


Weighted 14,800 22,400 28,400 44,500 52,800 75,900


Weighted 410 739 1,030 1,910 2,400 3,910


Weighted 1,590 2,290 2,810 4,130 4,770 6,440


Weighted 7,540 12,800 17,200 30,200 37,500 60,400


Weighted 622 1,210 1,720 3,150 3,890 6,000





number

Flood-flow region

Type




Weighted 173 400 615 1,290 1,680 2,980


Weighted 743 1,350 1,870 3,480 4,420 7,520


Weighted 2,290 3,150 3,830 5,620 6,480 8,690


Weighted 5,360 8,970 12,000 20,700 25,500 39,800


Weighted 4,460 7,940 11,300 22,400 29,400 53,500


Weighted 101 167 223 380 462 694


Weighted 6,310 9,710 12,300 18,700 21,900 30,300

01556400 3 Observed 204 371 525 1,020 1,310 2,230Predicted 243 417 556 912 1,090 1,550

Weighted 209 381 533 981 1,230 1,990


Weighted 2,560 3,960 4,990 7,510 8,690 11,700


Weighted 96 173 234 392 468 668


Weighted 1,410 2,250 2,880 4,490 5,260 7,280


Weighted 5,080 8,270 11,000 19,100 23,600 37,800


Weighted 13,400 21,400 28,100 47,100 57,400 88,000

Appendix 2 43




number

Flood-flow region

Type




Weighted 2,610 3,990 5,130 8,080 9,480 13,100


Weighted 287 517 707 1,250 1,540 2,440


Weighted 2,930 5,090 6,720 10,800 12,700 18,000


Weighted 4,310 6,880 8,980 14,800 17,900 26,900


Weighted 935 1,810 2,620 5,220 6,780 12,100


Weighted 14,000 21,900 27,700 42,400 49,400 68,000


Weighted 1,740 2,920 3,940 6,730 8,160 12,300


Weighted 14,400 20,200 24,000 32,400 36,000 44,000


Weighted 163 258 330 515 606 856


Weighted 6,010 10,400 14,100 24,700 30,600 48,100


Weighted 7,590 14,500 20,500 39,500 51,300 92,300


Weighted 2,610 4,690 6,540 12,200 15,400 25,500


Weighted 232 424 606 1,210 1,580 2,850





number

Flood-flow region

Type




Weighted 312 636 941 1,920 2,520 4,550


Weighted 6,130 9,660 12,300 19,000 22,200 30,500


Weighted 2,380 3,680 4,630 6,950 8,030 10,700


Weighted 747 1,480 2,200 4,750 6,410 12,500


Weighted 6,680 11,000 14,400 23,800 28,700 42,700


Weighted 335 714 1,090 2,380 3,180 5,980


Weighted 311 600 890 1,920 2,590 5,100


Weighted 243 451 667 1,400 1,830 3,250


Weighted 6,900 10,300 13,000 20,400 24,200 34,400

01571000 3 Observed 1,340 2,190 2,830 4,470 5,260 7,330Predicted 513 968 1,370 2,500 3,090 4,800

Weighted 1,280 2,030 2,580 4,010 4,740 6,730


Weighted 2,650 4,420 6,040 11,000 13,800 22,700


Weighted 1,670 2,900 3,900 6,680 8,170 12,800


Weighted 1,290 2,170 2,940 5,060 6,160 9,320

Appendix 2 45




number

Flood-flow region

Type




Weighted 3,510 5,670 7,470 12,300 14,700 21,600


Weighted 4,980 7,900 10,200 16,400 19,400 27,900


Weighted 1,160 1,830 2,340 3,750 4,490 6,630


Weighted 9,320 14,200 18,100 29,000 34,600 50,600


Weighted 949 1,730 2,490 4,900 6,260 10,600


Weighted 608 1,220 1,780 3,510 4,510 7,800

01573560 3 Observed 10,200 15,500 19,800 31,500 37,600 54,800

Predicted 11,600 18,700 24,100 37,500 43,900 61,100

Weighted 10,300 16,000 20,600 33,000 39,300 56,500


Weighted 14,900 22,000 28,100 46,700 57,100 89,300


Weighted 2,040 3,570 5,000 9,390 11,800 19,100


Weighted 247 662 1,160 3,180 4,670 11,500


Weighted 2,300 4,200 6,080 12,200 15,600 26,400


Weighted 688 1,100 1,390 2,160 2,560 3,680


Weighted 532 818 1,040 1,640 1,940 2,760





number

Flood-flow region

Type




Weighted 7,430 12,200 16,000 26,300 31,600 46,500


Weighted 10,800 15,200 18,400 26,500 30,400 40,400


Weighted 5,230 8,710 11,800 20,800 25,800 41,300


Weighted 444 875 1,290 2,660 3,470 6,120


Weighted 601 1,200 1,800 3,880 5,260 10,600


Weighted 444 819 1,150 2,190 2,790 4,730


Weighted 4,750 7,190 9,080 14,100 16,600 23,300


Weighted 5,990 9,790 13,100 23,100 28,900 46,800


Weighted 938 1,630 2,210 3,790 4,600 6,890


Weighted 383 748 1,090 2,190 2,860 5,070


Weighted 4,620 8,120 11,100 20,100 25,500 43,800

01614090 4 Observed 100 199 297 634 845 1,560Predicted 261 461 630 1,100 1,350 2,060

Weighted 124 265 403 810 1,030 1,740


Weighted 7,720 11,800 15,300 24,700 29,400 42,600

Appendix 2 47




number

Flood-flow region

Type



01638900 4 Observed 1,290 2,360 3,350 6,570 8,490 14,700Predicted 563 964 1,300 2,220 2,700 4,070

Weighted 1,170 1,990 2,670 4,890 6,250 10,800


Weighted 5,300 7,210 8,590 11,900 13,300 16,800


Weighted 437 885 1,300 2,670 3,540 6,700


Weighted 4,020 5,740 7,050 10,400 12,000 16,200


Weighted 7,320 12,000 16,100 28,900 36,300 60,100


Weighted 2,130 3,090 3,770 5,350 6,020 7,560


Weighted 23,200 31,400 37,200 50,900 57,200 72,800


Weighted 1,190 2,030 2,700 4,550 5,530 8,340


Weighted 3,770 5,330 6,480 9,170 10,300 13,200


Weighted 7,860 10,600 12,500 16,600 18,400 22,400


Weighted 628 780 892 1,190 1,320 1,650


Weighted 491 641 759 1,050 1,180 1,480

03015390 3 Observed 828 1,150 1,380 1,950 2,230 2,950Predicted 456 720 912 1,380 1,590 2,140

Weighted 780 1,050 1,250 1,750 1,990 2,650





number

Flood-flow region

Type




Weighted 7,480 10,100 11,800 15,400 16,900 20,400


Weighted 5,810 8,610 10,600 15,300 17,400 22,800


Weighted 9,200 12,600 15,000 20,700 23,100 28,700

03020440 3 Observed 310 411 478 628 693 847Predicted 221 375 495 801 949 1,340

Weighted 297 402 483 697 798 1,050


Weighted 7,710 10,800 13,100 18,500 21,000 27,500


Weighted 3,690 4,720 5,360 6,790 7,420 8,870


Weighted 2,890 4,210 5,130 7,560 8,840 12,600

03021700 3 Observed 291 432 537 797 921 1,250Predicted 202 348 464 763 908 1,300

Weighted 279 413 516 784 916 1,270


Weighted 10,500 14,100 16,600 22,100 24,400 29,900


Weighted 1,170 1,750 2,160 3,140 3,590 4,710


Weighted 1,620 2,300 2,830 4,130 4,720 6,240


Weighted 15,900 21,800 25,800 35,100 39,200 49,500


Weighted 14,300 18,200 20,700 26,200 28,500 33,400

Appendix 2 49




number

Flood-flow region

Type




Weighted 5,230 7,210 8,480 11,200 12,400 15,000


Weighted 243 451 634 1,170 1,460 2,360


Weighted 442 562 651 884 992 1,250


Weighted 395 718 1,000 1,880 2,380 3,990


Weighted 2,160 3,240 4,010 5,880 6,740 8,930


Weighted 9,130 14,000 17,400 26,100 30,500 43,400


Weighted 280 510 713 1,320 1,660 2,740

03029400 3 Observed 341 506 618 866 972 1,220Predicted 537 889 1,160 1,830 2,150 3,010

Weighted 366 588 769 1,210 1,410 1,870


Weighted 17,200 24,700 30,100 43,300 49,500 65,600


Weighted 21,600 31,100 37,900 54,800 62,800 83,700


Weighted 25,800 34,900 41,000 55,200 61,400 76,300


Weighted 109 184 240 380 444 604


Weighted 474 708 873 1,270 1,460 1,910





number

Flood-flow region

Type




Weighted 11,800 17,900 22,600 35,500 42,100 60,900


Weighted 4,430 7,070 9,260 15,500 19,000 29,200


Weighted 3,090 4,460 5,480 8,090 9,340 12,700


Weighted 7,410 10,300 12,500 18,000 20,600 27,300


Weighted 4,970 7,560 9,700 15,700 18,900 28,300


Weighted 9,090 12,500 14,700 19,600 21,600 26,500

03039200 4 Observed 134 206 261 401 470 651Predicted 200 356 489 864 1,060 1,630

Weighted 145 248 342 592 714 1,030


Weighted 10,400 16,900 22,100 36,600 44,100 65,700


Weighted 5,350 9,010 12,200 21,700 27,100 43,800


Weighted 16,600 26,900 35,500 60,900 75,100 118,000


Weighted 6,410 10,200 13,400 22,600 27,600 42,900


Weighted 299 412 513 795 932 1,290


Weighted 422 752 1,050 2,010 2,600 4,580

Appendix 2 51




number

Flood-flow region

Type




Weighted 5,200 7,600 9,510 14,500 17,000 23,400


Weighted 11,200 17,100 21,900 35,700 43,100 65,000


Weighted 5,980 9,190 11,800 19,000 22,800 33,900


Weighted 7,130 11,800 15,600 26,300 32,200 49,800


Weighted 39,500 59,000 74,400 117,000 139,000 204,000


Weighted 3,910 6,030 7,760 12,500 15,000 22,000


Weighted 272 644 1,060 2,800 4,140 9,840


Weighted 1,630 2,830 3,850 6,740 8,270 12,800


Weighted 61 99 134 231 280 410


Weighted 7,090 10,200 12,800 19,900 23,600 34,100


Weighted 7,160 10,500 12,800 18,200 20,600 26,400


Weighted 670 1,050 1,360 2,200 2,610 3,690


Weighted 4,340 7,600 10,300 18,100 22,700 37,100





number

Flood-flow region

Type




Weighted 833 1,510 2,050 3,540 4,320 6,520


Weighted 6,100 8,600 10,200 14,000 15,500 19,200

03074300 4 Observed 151 259 350 613 754 1,170Predicted 206 366 502 886 1,090 1,670

Weighted 160 287 400 718 883 1,350

03074500 4 Observed 2,260 3,240 3,920 5,510 6,220 7,990

Predicted 2,520 4,080 5,330 8,710 10,400 15,300

Weighted 2,280 3,320 4,110 6,040 6,930 9,140


Weighted 2,020 3,010 3,840 6,130 7,300 10,600


Weighted 1,030 1,840 2,560 4,740 5,990 9,930


Weighted 10,800 16,000 20,200 31,500 37,300 53,600


Weighted 4,040 5,870 7,170 10,300 11,700 15,100


Weighted 614 884 1,110 1,740 2,070 2,970


Weighted 32,400 45,600 55,500 80,800 93,200 126,000

03083000 4 Observed 235 423 592 1,120 1,430 2,390Predicted 174 311 428 759 933 1,430

Weighted 231 409 566 1,050 1,330 2,220


Weighted 36,600 55,400 69,400 105,000 123,000 172,000

03083600 4 Observed 184 342 492 997 1,310 2,340Predicted 217 385 528 930 1,140 1,750

Weighted 189 353 504 972 1,250 2,130

Appendix 2 53




number

Flood-flow region

Type




Weighted 408 657 836 1,290 1,510 2,070


Weighted 2,190 3,370 4,250 6,480 7,540 10,300


Weighted 5,520 8,310 10,300 14,800 16,800 21,500


Weighted 643 1,080 1,440 2,410 2,880 4,170


Weighted 651 840 977 1,320 1,470 1,860


Weighted 2,910 4,160 4,950 6,890 7,900 10,800


Weighted 529 969 1,320 2,290 2,800 4,270


Weighted 2,480 3,630 4,430 6,260 7,080 9,070


Weighted 1,450 2,050 2,460 3,310 3,660 4,420


Weighted 2,920 4,200 5,010 6,660 7,320 8,800


Weighted 8,010 12,000 14,800 21,000 23,900 31,200


Weighted 9,080 13,600 17,000 24,900 28,600 38,400


Weighted 172 285 368 590 706 1,040





number

Flood-flow region

Type




Weighted 7,960 11,200 13,700 19,900 22,900 30,600


Weighted 7,500 10,900 13,300 18,700 21,000 26,600


Weighted 3,660 5,750 7,420 11,800 14,000 19,900


Weighted 378 609 791 1,280 1,520 2,200


Weighted 9,090 13,600 17,000 25,200 29,100 38,800

03111150 3 Observed 533 933 1,240 2,010 2,380 3,310

Predicted 521 885 1,170 1,900 2,250 3,210

Weighted 532 923 1,220 1,970 2,330 3,270


Weighted 6,080 8,840 10,600 14,700 16,500 20,600


Weighted 132 222 290 458 537 738

04213075 3 Observed 321 495 619 912 1,050 1,370Predicted 293 516 697 1,170 1,410 2,050

Weighted 317 499 641 1,000 1,180 1,620


Weighted 717 1,130 1,460 2,350 2,810 4,120

Appendix 3 55A

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r Rea

ding

, Pa.

175

1979

-200

62,

430

3,41

04,

080

5,60

06,

270

0147

1000

Tulp

ehoc

ken

Cre

ek n

ear R

eadi

ng, P

a.21

119

79-2

006

2,65

03,

740

4,51

06,

290

7,10

001

4715

10Sc

huyl

kill

Riv

er a

t Rea

ding

, Pa.

880

1980

-200

616

,600

26,8

0034

,600

54,9

0064

,800

0147

2000

Schu

ylki

ll R

iver

at P

otts

tow

n, P

a.1,

150

1979

-200

621

,100

30,3

0036

,900

53,1

0060

,600

0148

0400

Birc

h R

un n

ear W

agon

tow

n, P

a.4.

5519

97-2

006

162

309

441

845

1,07

001

4806

85M

arsh

Cre

ek n

ear D

owni

ngto

wn,

Pa.

20.3

1974

-200

633

148

859

482

692

401

4807

00Ea

st B

ranc

h B

rand

ywin

e C

reek

nea

r Dow

ning

tow

n, P

a.60

.619

74-2

006

2,25

03,

640

4,66

07,

170

8,33

001

4808

70Ea

st B

ranc

h B

rand

ywin

e C

reek

bel

ow D

owni

ngto

wn,

Pa.

89.9

1974

-200

63,

320

5,10

06,

410

9,64

011

,200

0151

8000

Tiog

a R

iver

at T

ioga

, Pa.

282

1980

-200

65,

700

6,39

06,

780

7,51

07,

780

0151

8700

Tiog

a R

iver

at T

ioga

Junc

tion,

Pa.

446

1980

-200

66,

710

8,05

08,

950

11,0

0011

,800

0152

0000

Cow

anes

que

Riv

er n

ear L

awre

ncev

ille,

Pa.

298

1980

-200

64,

460

5,41

05,

980

7,15

07,

620

0153

4300

Lack

awan

na R

iver

nea

r For

est C

ity, P

a.38

.819

60-2

006

759

961

1,08

01,

300

1,39

001

5345

00La

ckaw

anna

Riv

er a

t Arc

hbal

d, P

a.10

819

60-2

006

2,39

03,

880

5,11

08,

620

10,5

0001

5360

00La

ckaw

anna

Riv

er a

t Old

For

ge, P

a.33

219

60-2

006

6,15

010

,500

14,0

0023

,800

28,9

00

56 Regression Equations for Estimating Flood Flows for Selected Recurrence IntervalsA

ppen

dix

3.

Floo

d-flo

w m

agni

tude

s fo

r sel

ecte

d re

curr

ence

inte

rval

s fo

r stre

amflo

w-g

agin

g st

atio

ns in

Pen

nsyl

vani

a w

ith d

rain

age

area

s le

ss th

an 2

,000

squ

are

mile

s an

d st

ream

flow

sub

stan

tially

affe

cted

by

upst

ream

regu

latio

n.—

Cont

inue

d

[Dat

a fr

om th

ese

stre

amflo

w-g

agin

g st

atio

ns w

ere

not i

nclu

ded

in th

e re

gres

sion

ana

lysi

s; m

i2 , sq

uare

mile

s; w

ater

yea

r, 12

-mon

th p

erio

d O

ctob

er 1

- Sep

tem

ber 3

0; a

ll flo

od fl

ows i

n cu

bic

feet

per

se

cond

]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-g

agin

g st

atio

n

Stat

ion

nam

eD

rain

age

area

(m

i2 )

Peri

od o

f re

cord

(w

ater

yea

r)1

Floo

d flo

ws,

com

pute

d fr

om s

trea

mflo

w-g

agin

g-st

atio

n da

ta

2-ye

ar5-

year

10-y

ear

50-y

ear

100-

year

0154

1200

WB

Sus

queh

anna

Riv

er n

ear C

urw

ensv

ille,

Pa.

367

1966

-200

64,

780

5,65

06,

210

7,43

07,

950

0154

1303

Wes

t Bra

nch

Susq

ueha

nna

Riv

er a

t Hyd

e, P

a.47

419

79-2

006

5,68

06,

710

7,39

08,

890

9,54

001

5415

00C

lear

field

Cre

ek a

t Dim

elin

g, P

a.37

119

61-2

006

6,24

09,

030

11,1

0016

,600

19,3

0001

5425

00W

B S

usqu

ehan

na R

iver

at K

arth

aus,

Pa.

1,46

019

61-2

006

20,0

0030

,300

38,8

0063

,100

76,0

0001

5440

00Fi

rst F

ork

Sinn

emah

onin

g C

r nea

r Sin

nem

ahon

ing,

Pa.

245

1956

-200

64,

900

6,15

06,

930

8,54

09,

190

0154

5000

Ket

tle C

reek

nea

r Wes

tpor

t, Pa

.23

319

62-2

006

4,66

05,

640

6,24

07,

440

7,91

001

5475

00B

ald

Eagl

e C

reek

at B

lanc

hard

, Pa.

339

1971

-200

62,

860

3,59

04,

020

4,90

05,

240

0156

3200

Ray

s Br J

unia

ta R

iver

bl R

ays D

am n

r Hun

tingd

on, P

a.96

019

73-2

006

11,9

0014

,900

16,6

0019

,600

20,8

0001

5755

00C

odor

us C

reek

nea

r Yor

k, P

a.22

219

47-2

006

3,95

06,

430

8,69

016

,000

20,3

0001

5745

00C

odor

us C

reek

at S

prin

g G

rove

, Pa.

75.5

1967

-200

61,

600

3,06

04,

580

10,3

0014

,300

0157

5000

Sout

h B

ranc

h C

odor

us C

reek

nea

r Yor

k, P

a.11

719

72-9

54,

240

8,07

011

,900

25,3

0034

,000

0302

0000

Tion

esta

Cre

ek a

t Tio

nest

a C

reek

Dam

, Pa.

479

1941

-91

6,60

08,

350

9,44

011

,700

12,6

0003

0215

20Fr

ench

Cre

ek n

ear U

nion

City

, Pa.

221

1972

-91

2,37

03,

100

3,55

04,

450

4,81

003

0231

00Fr

ench

Cre

ek a

t Mea

dvill

e, P

a.78

819

89-2

006

10,1

0012

,600

14,1

0017

,200

18,4

0003

0240

00Fr

ench

Cre

ek a

t Utic

a, P

a.1,

030

1971

-200

612

,100

14,7

0016

,200

19,0

0020

,000

0302

2554

Woo

dcoc

k C

reek

at W

oodc

ock

Cre

ek D

am, P

a.45

.619

75-9

160

877

587

71,

090

1,17

003

0275

00EB

Cla

rion

Riv

er a

t EB

Cla

rion

Riv

er D

am, P

a.73

.219

53-9

158

190

41,

170

1,91

02,

310

0302

8500

Cla

rion

Riv

er a

t Joh

nson

burg

, Pa.

204

1953

-200

63,

880

5,69

07,

050

10,5

0012

,200

0303

6000

Mah

onin

g C

reek

at M

ahon

ing

Cre

ek D

am, P

a.34

419

41-9

14,

910

6,56

07,

730

10,5

0011

,800

0303

9000

Cro

oked

Cre

ek a

t Cro

oked

Cre

ek D

am, P

a.27

819

41-9

13,

780

4,84

05,

470

6,73

07,

220

0304

2280

Yello

w C

reek

nea

r Hom

er C

ity, P

a.57

.419

71-2

006

1,36

02,

640

3,89

08,

260

11,0

0003

0425

00Tw

o Li

ck C

reek

at G

race

ton,

Pa.

171

1969

-200

64,

030

7,79

011

,400

24,1

0032

,100

0304

4000

Con

emau

gh R

iver

at T

unne

lton,

Pa.

1,36

019

52-9

117

,700

23,1

0026

,400

33,5

0036

,400

0304

7000

Loya

lhan

na C

reek

at L

oyal

hann

a D

am, P

a.29

219

42-9

13,

800

4,81

05,

440

6,73

07,

250

0304

8500

Kis

kim

inet

as R

iver

at V

ande

rgrif

t, Pa

.1,

830

1942

-200

621

,700

30,5

0036

,800

52,0

0059

,100

0307

7500

Youg

hiog

heny

Riv

er a

t You

ghio

ghen

y R

iver

Dam

, Pa.

436

1944

-91

4,99

06,

750

7,86

010

,200

11,1

0003

0810

00Yo

ughi

oghe

ny R

iver

bel

ow C

onflu

ence

, Pa.

1,03

019

42-2

006

16,1

0023

,000

28,2

0041

,400

47,8

00

Appendix 3 57A

ppen

dix

3.

Floo

d-flo

w m

agni

tude

s fo

r sel

ecte

d re

curr

ence

inte

rval

s fo

r stre

amflo

w-g

agin

g st

atio

ns in

Pen

nsyl

vani

a w

ith d

rain

age

area

s le

ss th

an 2

,000

squ

are

mile

s an

d st

ream

flow

sub

stan

tially

affe

cted

by

upst

ream

regu

latio

n.—

Cont

inue

d

[Dat

a fr

om th

ese

stre

amflo

w-g

agin

g st

atio

ns w

ere

not i

nclu

ded

in th

e re

gres

sion

ana

lysi

s; m

i2 , sq

uare

mile

s; w

ater

yea

r, 12

-mon

th p

erio

d O

ctob

er 1

- Sep

tem

ber 3

0; a

ll flo

od fl

ows i

n cu

bic

feet

per

se

cond

]

U.S

. Geo

logi

cal

Surv

ey

stre

amflo

w-g

agin

g st

atio

n

Stat

ion

nam

eD

rain

age

area

(m

i2 )

Peri

od o

f re

cord

(w

ater

yea

r)1

Floo

d flo

ws,

com

pute

d fr

om s

trea

mflo

w-g

agin

g-st

atio

n da

ta

2-ye

ar5-

year

10-y

ear

50-y

ear

100-

year

0308

2500

Youg

hiog

heny

Riv

er a

t Con

nells

ville

, Pa.

1,33

019

42-2

006

23,8

0035

,700

44,8

0068

,200

79,7

0003

0835

00Yo

ughi

oghe

ny R

iver

at S

uter

svill

e, P

a.1,

720

1942

-200

629

,200

44,0

0055

,300

84,5

0098

,800

0310

1500

Shen

ango

Riv

er a

t Pym

atun

ing

Dam

, Pa.

167

1935

-200

690

01,

150

1,31

01,

620

1,74

003

1028

50Sh

enan

go R

iver

nea

r Tra

nsfe

r, Pa

.33

719

66-2

006

4,48

05,

190

5,56

06,

170

6,38

003

1035

00Sh

enan

go R

iver

at S

harp

svill

e, P

a.58

419

39-9

14,

840

7,66

09,

920

16,1

0019

,300

0310

6300

Mud

dy C

reek

nea

r Por

ters

ville

, Pa.

51.2

1970

-200

634

948

157

479

389

203

1065

00Sl

ippe

ry R

ock

Cre

ek a

t Wur

tem

burg

, Pa.

398

1969

-200

66,

240

8,02

09,

060

11,1

0011

,900

2 Wat

er y

ear i

s def

ined

as a

12-

mon

th p

erio

d be

ginn

ing

Oct

ober

1 a

nd e

ndin

g Se

ptem

ber 3

0. T

he w

ater

yea

r is d

esig

nate

d by

the

cale

ndar

yea

r in

whi

ch it

end

s.

Roland and Stuckey— Regression Equations for Estim

ating Flood Flows for U

ngaged Streams in Pennsylvania—

Scientific Investigations Report 2008-5102

Printed on recycled paper

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