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Determination of the Primary and Secondary 

Source-Water Protection Areas for Selected 

Surface-Water Public-Supply Systems 

in South Carolina, 1999

By Andral W. Caldwell

U.S. GEOLOGICAL SURVEY 

Water-Resources Investigations Report 00-4097

Prepared in cooperation with the

South Carolina Department of Health and Environmental Control

Columbia, South Carolina 

2000
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY 

Charles G. Groat, Director

The use of firm, trade, and brand names in this report is for identification purposes 

only and does not constitute endorsement by the U.S. Government.

For additional information write to:

District Chief

U.S. Geological Survey

Stephenson Center, Suite 129

720 Gracern Road

Columbia, South Carolina 29210-7651

Copies of this report can be purchased 

from:

U.S. Geological Survey 

Information Services 

Box 25286, Federal Center 

Denver, CO 80225
CONTENTS

Abstract ...................................................................................................................................................................^ 1

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

Purpose and scope................................................................................................................................................... 2

Previous investigations............................................................................................................................................ 6

Acknowledgments...............................................................................................................................................^ 7

Methods for delineation of primary and secondary source-water protection areas .............................................................. 7

Intakes with only primary source-water protection areas..................................................................................................... 11

Intakes with primary and secondary source-water protection areas...................................................................................... 11

Determination of the 24-hour travel time distance.................................................................................................. 12

Determination of primary and secondary source-water protection areas................................................................ 14

Summary .......................................................................................................................................................................^ 14

Selected references......................................................................................................................................................^ 15

Supplemental data Pilot study estimation of travel time for the intake on Shaw Creek in Aiken, S.C.............................. 32

FIGURES

1-4. Maps showing:

1. Locations of major basins and surface-water intakes in South Carolina, 1999................................................. 3

2. Physiographic provinces and locations of the Aiken, Belton-Honea Path, and Greenwood

surface-water intakes, South Carolina ............................................................................................................... 4

3. Final 24-hour time-of-travel points for the 10-, 50-, and 90-percent exceedance flows

for the Aiken intake on Shaw Creek, South Carolina........................................................................................ 10

4. Locations of surface-water intakes on (A) the Waccamaw River, Atlantic Intracoastal Waterway,

and Bull Creek; and (B) Foster Creek and Bushy Park Reservoir, South Carolina........................................... 13

TABLES

1. Locations and descriptions of intakes in South Carolina, 1999 ................................................................................. 5

2. Surface-water intakes and drainage areas in South Carolina with only primary source-water

protection areas, 1999 ................................................................................................................................................ 11

3. Twenty-four-hour travel distances for surface-water intakes in South Carolina, 1999.............................................. 16

4. Identifying information for primary and secondary source-water protection areas for 45 surface-water

intakes in South Carolina, 1999................................................................................................................................. 20

Contents
CONVERSION FACTORS, VERTICAL DATUM, AND ABBREVIATIONS

Multiply

meter (m) 

kilometer (km)

square meter (m2) 

square kilometer (km )

cubic meter (m )

cubic meter per second (m /s) 

meter per square second (m/s2)

By

Length

3.281 

0.6214

Area

10.76 

0.3861

Volume

35.31

Flow rate

35.31 

3.281

To obtain

foot 

mile

square foot 

square mile

cubic foot

cubic foot per second 

foot per square second

Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929 (NGVD 

of 1929) a geodetic datum derived from a general adjustment of the first-order level nets of both 

the United States and Canada, formerly called Sea Level Datum of 1929.

Abbreviations used in this report:

BLTM Branched Lagrangian Transport Model

GDA gage drainage area

GQio gage flow for the 10-percent exceedance flow

GQ50 gage flow for the 50-percent exceedance flow

GQ90 gage flow for the 90-percent exceedance flow

hr hour

HUC hydrologic unit code

IDA intake drainage area

MGQ annual mean flow at gage

RK river kilometer

SCDHEC South Carolina Department of Health and Environmental Control

SWAP source-water assessment and protection

TOT time of travel

TOT10 time of travel for the 10-percent exceedance flow

TOT50 time of travel for the 50-percent exceedance flow

TOT90 time of travel for the 90-percent exceedance flow

USEPA United States Environmental Protection Agency

USGS United States Geological Survey

yrs years

IV Contents
Determination of the Primary and Secondary SourceWater Protection Areas for Selected Surface-Water 

Public-Supply Systems in South Carolina, 1999

ByAndral W. Caldwell

ABSTRACT

In a 1998 pilot project, the U.S. Geological 

Survey developed methods to determine in-stream 

travel distance and the primary and secondary 

source-water protection areas for protecting 

surface-water public-supply intakes. Three intakes 

in South Carolina were used to develop and test 

the methods. To verify the statewide applicability, 

these methods were applied to the remaining 71 

intakes in South Carolina.

The 24-hour travel distance from an intake 

computed for the 10-percent exceedance flow of 

the intake was the distance used to segment the 

primary and secondary source-water protection 

areas. The primary source-water protection area 

encompasses all 14-digit Hydrologic Unit Code 

basins that adjoin the streams, tributaries, and 

reservoirs between an intake and the computed 

10-percent exceedance flow travel distance 

upstream from the intake. The remainder of the 

intake drainage basin upstream from the primary 

source-water protection area is designated as the 

secondary source-water protection area. The 

length of the primary travel-time segment was 

reduced substantially if the travel time through a 

reservoir was included in the 24-hour travel-time 

calculation. If the reservoir were to be removed 

from the flow system after determining the 

primary travel-time segment, the segment would 

have to be recalculated. For this study, the effects 

of all reservoirs with volumes less than that of

Fishing Creek Reservoir are not included in 

determining the primary travel-time segment. 

However, for intakes with primary travel times 

that extended into larger reservoirs, the base of the 

larger reservoir's dam was considered to be the 

upstream limit of the primary protection area. If an 

intake is located on any part of a reservoir, the 

primary source-water protection area for the 

reservoir intake includes all 14-digit Hydrologic 

Unit Code basins adjoining the reservoir and the 

feeder streams within a 24-hour travel distance 

upstream from the headwaters of the reservoir. 

The 24-hour travel distance was determined on the 

main stream(s) and selected tributaries upstream 

from 45 intakes with drainage areas that have more 

than 24-hours of in-stream travel time between the 

intake and the 14-digit Hydrologic Unit Code 

basin(s) in the headwaters of the drainage basin.

A total of 29 intakes in South Carolina have 

drainage areas that are equal to or less than one 

14-digit Hydrologic Unit Code basin, or are 

estimated to have less than 24-hours of in-stream 

travel time between the intake and the 14-digit 

Hydrologic Unit Code basin in the headwaters of 

the drainage basin. For these intakes, the 24-hour 

travel distance was not calculated, and the entire 

drainage basin upstream from the intake was 

designated as the primary source-water protection 

area.

The travel-distance method was not 

applicable for five intakes in coastal areas because

Abstract 1
of tidal conditions. Therefore, one-dimensional 

dynamic flow and transport models were applied 

to these intakes to determine the primary and 

secondary source-water protection areas.

INTRODUCTION

Public drinking-water systems that rely on water 

withdrawals from streams or reservoirs are susceptible 

to potential contaminants from sources within drainage 

basins that supply water to these sources. Contaminants 

can enter a source-water system directly by spills to 

streams or reservoirs, or indirectly by overland runoff 

and ground water. The chemical and physical 

properties of a potential contaminant and the location 

of its source in a drainage basin determine the likely 

path and, hence, travel time for the contaminant to 

reach the surface-water intake. Therefore, travel time is 

one factor in determining the susceptibility of the 

surface-water intake, which hereafter will be referred 

to in this report as intake.

In implementing the 1996 amendments to the 

Federal Safe Drinking Water Act, the U.S. 

Environmental Protection Agency (USEPA) initiated 

the Source-Water Assessment and Protection (SWAP) 

Program. Two objectives of the SWAP Program are to 

focus attention on the susceptibility of public drinkingwater supplies to contamination and to ensure a future 

supply of clean water to public-supply systems. The 

SWAP Program consists of three parts: (1) delineation 

of source-water protection areas for all public drinkingwater systems, (2) inventory of potential contaminant 

sources within the source-water protection areas, and 

(3) determination of the susceptibility of intakes to 

potential contaminant sources.

The South Carolina Department of Health and 

Environmental Control (SCDHEC) developed a State 

SWAP plan in February 1999, which was approved by 

the USEPA in October 1999 (D. Baize, South Carolina 

Department of Health and Environmental Control, oral 

commun., 1999). The SCDHEC plans to implement the 

State SWAP plan for most of the public water supplies 

in South Carolina by May 2003 (R. Devlin, South 

Carolina Department of Health and Environmental 

Control, oral commun., 1999). In part one of the State 

SWAP plan, the primary and secondary source-water 

protection areas were determined for the drainage areas 

upstream from selected intakes; these areas will be 

used to prioritize the inventory of potential

contaminant sources and to assess susceptibility to 

potential contamination (fig. 1).

As part of the development of the State SWAP 

plan in 1998, the U.S. Geological Survey (USGS) 

entered into a cooperative agreement with the 

SCDHEC to develop methods to determine in-stream 

travel distance and the primary and secondary sourcewater protection areas for protecting surface-water 

intakes (Lanier and Falls, 1999; South Carolina 

Department of Health and Environmental Control, 

1999). Three representative intakes were chosen to 

develop and test the methods in the 1998 pilot project 

(fig. 2). These intakes include the Aiken intake on 

Shaw Creek (Coastal Plain stream example), the 

Belton-Honea Path intake on the Saluda River 

(Piedmont stream example), and the Greenwood intake 

on Lake Greenwood (reservoir example).

In June 1999, the USGS entered into a 

cooperative agreement with the SCDHEC to verify the 

statewide applicability of source-water protection 

methods previously developed by the USGS for the 

South Carolina SWAP plan (South Carolina 

Department of Health and Environmental Control, 

1999). These methods include estimating in-stream 

travel distance and delineating the primary and 

secondary source-water protection areas for intakes in 

South Carolina. The methods were applied to 71 

intakes in South Carolina (fig. 1; table 1). The travel 

distances and the primary and secondary source-water 

protection areas delineated in this study will be used by 

the SCDHEC to prioritize the inventory of potential 

contaminant sources and to implement a susceptibility 

assessment for each intake in South Carolina.

Purpose and Scope

The purpose of this report is to document the 

delineation of the primary and secondary source-water 

protection areas for 74 water-supply intakes in South 

Carolina. In addition, the in-stream 24-hour (hr) travel 

distance is documented for the 10-, 50-, and 90-percent 

exceedance flows for selected intakes in South 

Carolina.

The scope of this report includes verification and 

application of the source-water protection methods 

(South Carolina Department of Health and 

Environmental Control, 1999). These methods are used 

to determine the 24-hr in-stream travel distance for the 

10-, 50-, and 90-percent exceedance flows, and the 

primary and secondary source-water protection areas

Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
o

Q.o

Broad River Basin

fZ^^tSx'" S23102

' ' T^rfV.

S23103.S39%4? s^m: r;

Q2 S39106. . Y -m;-'...r SJ/ U^ o'

37103 «~,s' 

VS37104 S37*^2

S04101 PWS1U!> S301W

X S30106« ^ N c^ni no >->

,5\ :' *:£< S32103« J, \ S^Hos^ r.

t \ ^, -' S321(«(

;t-'^iSl>i-'l J* . ' - <" rilT«r'"-if-!.%-JH PW?M°8104 ' "f^%!

' /^^.'-<-..',':-.'; (>''-'^^

msS^-M^SJC^ - SIGH*\^° W-' U( S10102«^LJLi A 3101of;t

Surface-water intake and 319101 intake number

'"s^iof// * ' 'W/ Pee Dee

River Basin

Saluda River/ 

Edisto River Basins

Catawba River/ Santee River 

Basins

80 MILES

Figure 1. Locations of major basins and surface-water intakes in South Carolina, 1999.
a

2- CD"301

-3 

w oTJ 

O

3-oCD

CO

CDCObCD CD CD

83°

North Carolina

' .B/ewett

't Falls " Lake I

, Belton-Honea

Greenwood intake

1 GfeenWoodO

EXPLANATION

State boundary 

Physiographic boundary 

Stream Surface-water intake 0 20 40 60 80 KILOMETERS

80 MILES

Base from U.S. Geological Survey 1:2,000,000 scale Digital Line Graphs

Figure 2. Physiographic provinces and locations of the Aiken, Belton-Honea Path, and Greenwood surface-water intakes, South Carolina.
Table 1. Locations and descriptions of intakes in South Carolina, 1999 (from R. Devlin, South Carolina Department of 

Health and Environmental Control, written commun., June 1999)

Intake no. Operator Latitude Longitude Main stream or reservoir

Saluda-Edisto Basin

} S02101

S04105

S10101

| S23101

S23102

|_S24101

S30101

[T30102

S30106

|_ S32101

S32102

[_S32103

S32104

[~S32105

S32107

S36101

S38101

[ S39101

S40101

pS40102

City of Aiken

Belton-Honea Path Water Authority

Charleston Commission of Public Works

Greenville Water System

Greenville Water System

Greenwood Commission of Public Works

Laurens Commission of Public Works

Laurens Commission of Public Works

Laurens Commission of Public Works

City of Cayce

City of West Columbia

City ofLexington

Town of Batesburg-Leesville

Town of Batesburg-Leesville

City of West Columbia

City of Newberry

Orangeburg Department of Public Utilities

Easley Combined Utility

City of Columbia

City of Columbia

33°36'19"

34°31'47"

33°01'59"

35°08'28"

35°03'51"

34°15'30"

34°30'15"

34°28'28"

34°28'36"

33°56'04"

33°59'52"

33°58'25"

33°51'47"

33°53'40"

34°00'56"

34° 11 '09"

33°29'28"

34°52'00"

34°00'14"

34°05'51"

81 0 41'11"

82°22'37"

80°23'15"

82°24'33"

82°40'20"

82°01'47"

82°01'39"

82°08'38"

82°08'29"

81°04'56"

81°03'27"

8ri4'12"

81°28'08"

81°31'49"

81°14'33"

81°43'41"

80°52'41"

82°29'21"

81°03'19"

81"13'48"

Shaw Creek

Saluda River

Edisto River

North Saluda River

Table Rock Reservoir

Lake Greenwood

Reedy Creek

Rabon Creek

Lake Rabon

Congaree Creek

Saluda River

Twelve Mile Creek

Lightwood Knot Creek

Duncan Creek

Lake Murray

Saluda River

North Edisto River

Saluda Lake

Broad River Canal

Lake Murray

-

~

"n

I]

n~i

Broad Basin

S11101

[ S11102

S20101

| S20104

S23104

| S30103

S30104 

[136T02

S36103

S42101

S42102

1 S42103

S42104

[ S44101

S46102

S46103

Gaffney Board of Public Works

Gaffney Board of Public Works

Town of Winnsboro

Town of Winnsboro

Greer Commission of Public Works

City of Clinton

City of Clinton

Town of Whitmire

Town of Whitmire

Spartanburg Water System

City of Landrum

City of Landrum

35°06'29"

35°08'51"

348 20'27"

34°21 I31"

34°58'38"

34°32'47"

34°35'27"

34°30'44"

34°29'41"

35°06'37"

35°10'49"

35°10'48"

Stinlev, Jackson, Wellford, Duncan Water District 34°56'24"

City of Union

City of York

City of York

34°43'57"

34°59'57"

34°59'16"

81°37'16"

81°36'34"

8 1° 09' 18"

81°06'42"

82°14'43"

81°54'25"

81°53'16"

81°36'26"

81°37'07"

81°58'13"

82°14'29"

82°16'23"

82°07'29"

81°29'22"

81°15'10"

Lake Welchel

Broad River

Sand Creek

192 Acre Lake

South Tyger River

Duncan Creek

Enoree River

Enoree River

Duncan Creek

South Pacolet River

Vaughns Creek

Hog Back Mountain

Middle Tyger River

Broad River

Lake Carolyn

-3

j

8 1° 1 7' 1 8" Lake Caldwel 1 (Turkey Creek)

Catawba-Santee Basin

SOS 104

S10102

<sloi03

1 S10104

S12101

O O Q 1 A. 1

o^o 1 \J 1

S28102

LJ329106

S46101

S46109

Santee Cooper Regional Water

Charleston Commission of Public Works

Charleston Commission of Public Works

Charleston Commission of Public Works

Chester Metro

CityofCamden

Lugoff-Elgin Water Authority

Catawba River Water Treatment Plant

City of Rock Hill

City of Rock Hill

33°14'10"

32°58'38"

32°55'44"

32°58'47"

34°42'29"

34° 16' 19"

34°20'03"

34°51'0r

35°00'59"

34°59'10"

80°00'40"

79°59'05"

80°00'59"

79°56'29"

80°52'04"

80°35'17"

80°42'22"

80°51'58"

81°00'38"

80°58'52"

Lake Moultrie

Foster Creek

Goose Creek Reservoir

Bushy Park Reservoir

Catawba River

Little Pine Tree Creek

Lake Wateree

Catawba River

Catawba River

Lake Wylie

~i

Pee Dee Basin

S13101

S13102

S13103

S13104

L S13105

Town of Cheraw

City of Pageland

City of Pageland

City of Chesterfield

Town of Jefferson

34°42'26"

34°41'45"

34°45'13"

34°44'08"

34°37'52"

79°52'34"

80°25'52"

80°23'52"

80°03'48"

80°25'12"

Great Pee Dee River

Lake Terry

Old Town Pond

Thompson Creek

Lynches River

Introduction
Table 1. Locations and descriptions of intakes in South Carolina, 1999 (from R. Devlin, South Carolina Department of 

Health and Environmental Control, written commun., June 1999)-Continued

Intake no. 

(fig- 1) Operator Latitude Longitude Main stream or reservoir

Pee Dee Basin (Continued)

Georgetown County Water and Sewer District/ 

Waccamaw Neck

Grand Strand Water and Sewer Authority

B 

City of Bennettsville

33°38'60" 79°07'23" 

JSilJgPlii 

79°40'24"

Bull Creek

ill 

Lake Paul Wallace

Savannah-Salkehatchie Basin

Rocky River/Lake Russell

Flat Rock Pond

1 

Savannah River

| 

Lake Keowee

mfelll

Beaufort, Jasper Water and Sewer Authority

Greenville Water System

McCormick Commission of Public Works

^i8Si^>S^BI

City of Walhalla

33°55'09"

aifp^l

34°43'25"

Rocky Creek

Coneross Creek 

^SrSeSS^i^i 

Chauga River

Twelve Mile Creek

Twelve Mile Creek

Westminster Commission of Public Works

City ofPickens

Easley Central Water District

upstream from intakes in South Carolina and in 

applicable parts of North Carolina and Georgia.

Previous Investigations

In 1998, as part of a cooperative project with the 

SCDHEC, the USGS developed methods to determine 

in-stream travel distance and the primary and secondary 

source-water protection areas for protecting surfacewater intakes (Lanier and Falls, 1999; South Carolina 

Department of Health and Environmental Control, 

1999). These methods (described later in this report) 

were applied to three intakes in South Carolina. The 

primary source-water protection area for an intake 

includes all of the hydrologic units, identified by 

14-digit Hydrologic Unit Codes (HUC's) (Bower and 

others, 1999), that adjoin the stream within a 24-hr 

(10-percent exceedance flow) travel distance upstream 

from the intake. These subwatersheds generally range 

in size from 12.1 square kilometers (km2) to 162 km2 

and serve as a reference for drainage area information 

(Bower and others, 1999). The 24-hr travel time was

selected because the SCDHEC estimated that an intake 

operator would be unable to react and make proper 

adjustments for contaminant spills in less than 24 hrs 

(D. Baize, South Carolina Department of Health and 

Environmental Control, oral commun., February 1998). 

If the drainage basin for an intake is larger than the 

primary source-water protection area, the remainder of 

the basin upstream from the primary source-water 

protection area is designated as the secondary sourcewater protection area.

The optimal method for estimating the travel 

time of a potential contaminant is to collect time-oftravel (TOT) data for high-, intermediate-, and lowflow conditions upstream from an intake. However, this 

method is data-intensive and is not a feasible method 

for most surface-water intake operators. Therefore, a 

simpler method is needed to estimate the travel time of 

a potential contaminant for streams where little or no 

travel-time data are available. In-stream travel-time 

methods described by Jobson (1996) provide guidance 

for predicting travel time and dispersion in streams and 

rivers by using readily attainable data. As described by 

Jobson (1996), TOT data from more than 980

Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
subreaches for approximately 90 rivers in the United 

States were used to develop three regression equations 

that include up to four variables (drainage area, reach 

slope, annual mean flow, and the measured flow for the 

reach at the time of the TOT study) to compute the 

mean velocity between two points. For each of the 

three mean-velocity equations, a maximum probable 

velocity equation was developed, for which 99 percent 

of the observed velocities were smaller.

A hydrologic analysis of TOT studies for 

selected South Carolina streams was conducted by the 

USGS to verify use of Jobson's (1996) three meanvelocity equations for computing mean velocity for 

streams in South Carolina. In this analysis, mean flow 

velocities from 45 TOT studies (23 in the Piedmont and 

22 in the Coastal Plain) on 19 streams were compared 

to the velocities computed by using Jobson's three 

mean-velocity equations. Results verify that equation 

12 in Jobson (1996) (equation 1 below) reasonably 

estimated the velocities in South Carolina Piedmont 

streams (fig. 2) by using drainage area, reach slope, 

annual mean flow, and measured flow as explanatory 

variables. Equation 14 in Jobson (1996) (equation 2 

below) reasonably estimated velocities in South 

Carolina Coastal Plain streams (fig. 2) by using 

drainage area, annual mean flow, and measured flow as 

explanatory variables. The equations are defined as 

follows:

South Carolina Piedmont streams:

Vp = 0.094 + 0.

South Carolina Coastal Plain streams:

Vp = 0.020 + 0.

a (1)

a , (2)

where

Vp = mean velocity of the peak concentration, in 

meters per second;

D'a = dimensionless drainage area =

where

g = acceleration of gravity, 9.81 meters per 

square second;

Da = average drainage area for the segment 

of interest, in square meters; and

Qa = annual mean flow of segment of 

interest, in cubic meters per second;

Q'a - dimensionless relative flow = Q/Qa ', 

S = reach slope, meter per meter; and

Q = average river flow at time of the measurement, in cubic meters per second.

Acknowledgments

The author is grateful to Mr. David Baize, South 

Carolina Department of Health and Environmental 

Control, for administrative and technical support and to 

Mr. Rob Devlin, South Carolina Department of Health 

and Environmental Control, for providing selected 

intake data.

METHODS FOR DELINEATION OF 

PRIMARY AND SECONDARY SOURCEWATER PROTECTION AREAS

Measured streamflow velocities from TOT 

studies for South Carolina streams were compared to 

streamflow velocities calculated by using empirical 

flow-velocity equations (Jobson, 1996). Results of this 

comparison were used to determine the equations that 

best predict streamflow velocity for streams in the 

Piedmont and Coastal Plain of South Carolina (fig. 2). 

Streamflow velocities for gaged and ungaged streams 

in the Piedmont and Coastal Plain of South Carolina 

can be estimated by using equation 1 for Piedmont 

streams and equation 2 for Coastal Plain streams 

(South Carolina Department of Health and 

Environmental Control, 1999). By using these 

equations specific to the Piedmont and Coastal Plain 

physiographic provinces, streamflow velocity was 

calculated at a high in-stream flow (10-percent 

exceedance) and multiplied by 24 hrs to determine a 

24-hr (10-percent exceedance) travel distance 

upstream from the intake. As previously stated, a 24-hr 

time period was chosen because the SCDHEC 

estimated an intake operator would be unable to react 

and make proper adjustments for contaminant spills in 

less than 24 hrs (D. Baize, South Carolina Department 

of Health and Environmental Control, oral commun., 

February 1998). A 24-hr travel distance was computed 

for high (10-percent exceedance), intermediate 

(50-percent exceedance), and low (90-percent exceedance) flows at the request of the SCDHEC. The stream 

segment between the intake and the 24-hr point 

computed at high flow is referred to in this report as the 

primary travel-time segment. As previously stated, the 

primary source-water protection area encompasses all 

14-digit HUC basins between the intake and the 24-hr 

point computed at high flow. The remainder of the

Methods for Delineation of Primary and Secondary Source-Water Protection Areas
basin upstream from the primary source-water 

protection area is designated as the secondary sourcewater protection area. These procedures also were 

applied to tributaries of the main stream that have 

drainage areas of at least 20 km2 and are contained in 

the primary travel-time segment. Tributaries that drain 

areas less than 20 km2 are considered to be too small 

for evaluation; if a spill occurs within these small 

tributaries, the travel time from the confluence of the 

small tributary and the main stem to the intake is used 

as the response time.

Reservoirs are a common part of the surfacewater flow systems in the Piedmont and the Coastal 

Plain of South Carolina. The length of the primary 

travel-time segment is reduced substantially if the 

travel time through a reservoir is included in the 24-hr 

travel-time calculation. If the reservoir were to be 

removed from the flow system after determining the 

primary travel-time segment, the segment would have 

to be recalculated. For this study, the effects of all 

reservoirs with volumes less than that of Fishing Creek 

Reservoir (fig. 2) are not included in determining the 

primary travel-time segment. The 7 steps for estimating 

the 24-hr travel distance for a generic site are given 

below.

1. Determine drainage areas and stream 

distances:

The intake drainage area (IDA) is delineated for 

the stream of interest. The stream channel is divided 

into 1- or 5-kilometer (km) intervals from the intake to 

a point approximately 55 km upstream. The distance of 

55 km was chosen because the empirically derived instream flow velocity typically results in a 24-hr travel 

distance of less than 55 km. The 5 5-km stream segment 

is then used in computing the slopes and for 

referencing the computed 24-hr travel distances.

2. Determine reach slope (Piedmont sites only):

Contour elevations and intervening distances are 

tabulated for every topographic contour between the 

first contour downstream from the intake and the 

contour closest to the 5 5-km point upstream from the 

intake, or at the headwaters of the basin. The slope 

between each contour is calculated for the study reach. 

A weighted average reach slope is computed by 

multiplying the slope between each contour by the 

distance between the contours, summing the products, 

and dividing the sum by the total distance from the 

downstream-most to the upstream-most contour.

3. Select an appropriate gaging station:

The USGS annual data report for South Carolina 

(Cooney and others, 1998) can be used to determine if 

any USGS gaging stations (active or discontinued) are 

located on or near the stream of interest. The minimum 

length of record required for the station is 13 years 

(yrs). This number is based on the minimum 

requirement of 10 yrs set forth in Bulletin 17B (U.S. 

Water Resources Council, 1981) for computing floodfrequency curves, with an additional 3 yrs added to be 

conservative.

If two or more USGS gaging stations are located 

on the stream of interest, the gaging station with a 

drainage basin that is closer in size to the IDA is used. 

If no gaging stations are located on the stream of 

interest, data can be used from a gaging station in a 

nearby basin preferably one in the same 

physiographic region. If additional gaging stations are 

located in nearby basins, a gaging station with a 

drainage area that has land use and soil type similar to 

the IDA of the stream of interest is selected.

The information needed for the gaging station 

includes gage drainage area (GDA), annual mean flow 

(MGQ), and the 10-, 50-, and 90-percent exceedance 

flows (GQ 10, GQ5Q, and GQ90). The GQjQ for a stream 

is a discharge that is exceeded 10 percent of the time for 

a designated period of time and represents a high flow. 

The empirical velocity equations do not apply to 

overbank flow conditions that would occur during 

flood flows. Flows at or below the GQjQ for a stream 

typically are contained within the stream channel. 

Therefore, the GQ 10 for a gaging station is used to 

calculate the high-flow velocity of the stream rather 

than extreme flood-flow conditions. The 50- and 90- 

percent exceedance flows for a stream represent 

intermediate and low flows, respectively. The 10-, 50-, 

and 90-percent exceedance flows for the intake are 

estimated by multiplying the GQ JQ GQ5Q and GQ9Q by 

the ratio of the drainage area for the intake to the 

drainage area for the gaging station.

4. Determine the 24-hour range:

Rather than delineating drainage areas 

throughout the basin upstream from the intake to 

determine the 24-hr travel distance, a 24-hr range can 

be determined by computing the minimum and 

maximum 24-hr travel distance upstream from the 

intake. Once the range has been defined, only that part 

of the basin between these distances needs to be further 

subdivided.

8 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
Examining the exponents of equations 1 and 2 

(Previous Investigations section), it can be seen that the 

average velocity is proportional to the magnitude of 

Da, Q, and Qa . Of these three parameters, only Da and 

Q can be varied. Da is the average drainage area for the 

segment of interest, or (Du/s+Dd/^)l2, where Du/s is the 

upstream drainage area and Dd/s is the downstream 

drainage area (both in square meters). If Dd/s is equal to 

the IDA, then only Du/s can be varied. Therefore, to 

determine the maximum Da, Du/s also is set equal to the 

IDA (Da = IDA). For the minimum Da, Du/s is set to

For Q, the maximum is 10-percent exceedance 

flow and the minimum is 90-percent exceedance flow. 

An average velocity must be computed for both the 

maximum and minimum Da and Q values. The 24-hr 

range then can be computed by using these maximum 

and minimum velocities.

If the minimum 24-hr travel distance is greater 

than the total length of the basin upstream from the 

intake, then the entire basin is contained within the 

24-hr travel distances for all three flows, and the 

computation of the maximum 24-hr distance is not 

necessary. For Piedmont basins, if the maximum 24-hr 

distance is greater (or less) than the distance to the 

farthest-measured upstream contour, then the reach 

slope to the first contour upstream from the maximum 

24-hr travel distance will need to be recomputed and a 

new weighted average reach slope calculated. The 

minimum and maximum 24-hr travel distance then can 

be recomputed by using the new reach slope.

5. Delineate drainage areas within the 24-hour 

range:

The drainage area is delineated for the area 

upstream from the minimum 24-hr travel distance. 

Moving upstream between the minimum and 

maximum 24-hr travel distance, the reach is 

proportionally subdivided into weighted drainage-area 

increments where each increment is no greater than 30 

percent of the previous drainage area. By subdividing 

the 24-hr range into these increments, the change in the 

average velocity between increments will be kept to 

about 10 percent. The basin will need to be subdivided 

upstream and downstream from tributaries if they 

contribute at least 30 percent of the total area at the 

point of confluence. If the maximum 24-hr travel 

distance exceeds the distance to the basin headwaters, 

the basin does not need to be subdivided into drainage 

areas of less than 20 km . This will not greatly decrease

the accuracy of the computation, but will notably 

decrease the drainage area computations, which can be 

time consuming.

6. Determine average drainage areas and final 

velocities:

The incremental drainage areas are tabulated 

from the intake to the maximum 24-hr travel point. The 

tabulation should include the drainage areas at the 

minimum and maximum travel-time points, drainage 

areas delineated between the minimum and maximum 

travel points, and the river kilometer (RK) where each 

drainage area is located. If the maximum 24-hr travel 

distance is greater than the length of the basin, then the 

total length of the basin is determined and the drainage 

area is assigned a value of zero at the headwaters. Then, 

starting at the intake and proceeding upstream, the 

average drainage area (Da) is computed for each 

segment. For example, the first Da would be computed 

as the average of the IDA and the delineated drainage 

area at the minimum 24-hr travel point. The Da at the 

second segment would be the average of the delineated 

drainage area at the minimum 24-hr travel point and the 

next drainage area subdivision upstream. Once all Z)a 's 

are determined, the velocity for each segment is 

computed by using the 10-, 50-, and 90-percent 

exceedance flows in conjunction with either equation 1 

or 2, as appropriate.

7. Determine the 24-hour travel distance:

For each segment between the subdivided 

drainage areas, the TOT is computed for the 10-, 50-, 

and 90-percent exceedance flow velocities. For each 

flow, the computation would begin with the TOT at the 

first segment, which would include the IDA, and 

proceed upstream adding the TOT's from each 

segment until 24 hrs is exceeded. Then 24 hrs is 

subtracted from the summed TOT. This difference is 

multiplied by the velocity of the segment where the 

TOT exceeded 24 hrs. This product is the distance 

where the 24-hr point was exceeded. The location of 

the final 24-hr TOT point is computed by subtracting 

this distance from the location of the upstream end of 

the segment in which 24 hrs was exceeded. The 24-hr 

travel distance computed for the 10-percent 

exceedance flow is the primary travel distance used to 

segment the source-water protection areas. An example 

of the final 24-hr TOT points for the 10-, 50-, and 90- 

percent exceedance flows is shown in figure 3.

Methods for Delineation of Primary and Secondary Source-Water Protection Areas
15

EXPLANATION

Pond

Basin boundary

Stream

River kilometer

Surface-water intake

o Final 24-hour time-of-travel 

TOTso point for the 10-, 50-, and

90-percent exceedance flows

N

A

6 KILOMETERS

Figure 3. Final 24-hour time-of-travel points for the 10-, 50-, and 90-percent exceedance flows for the Aiken intake on Shaw 

Creek, South Carolina.

10 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
As part of the 1998 USGS pilot project, these 

methods were applied to the Aiken intake on Shaw 

Creek, the Belton-Honea Path intake on the Saluda 

River, and the Greenwood intake on Lake Greenwood 

(fig. 2). As an example, the computation of the 24-hr 

travel distance for the 10-percent exceedance flow for 

the Shaw Creek intake is included as supplemental data 

at the end of the report (T.H. Lanier and W.F. Falls, 

U.S. Geological Survey, written commun., 1998).

INTAKES WITH ONLY PRIMARY SOURCEWATER PROTECTION AREAS

An intake has only a primary source-water 

protection area if the upstream drainage area is equal to 

one or part of one HUC basin, or is conservatively 

estimated to have less than 24 hrs of in-stream (highflow) travel time between the intake and the HUC basin 

in the headwaters of the drainage basin (T.H. Lanier and 

W.F. Falls, U.S. Geological Survey, written commun., 

1998). For such an intake, the 24-hr travel distance does 

not have to be calculated to determine that the entire 

drainage area is designated as a primary source-water 

protection area. The 29 intakes with only primary 

source-water protection areas are listed in table 2 along 

with the 14-digit HUC basins, the corresponding 

drainage areas, and the intake drainage areas.

INTAKES WITH PRIMARY AND 

SECONDARY SOURCE-WATER 

PROTECTION AREAS

Several intakes in South Carolina have large 

source-water protection areas with streams, tributaries, 

and reservoirs that extend upstream from the computed 

24-hr travel distance. The source-water protection area 

for some intakes extend into the neighboring States of 

North Carolina and Georgia. These source-water 

protection areas can be divided into primary and 

secondary protection areas by using the computed 24-hr 

travel distance and the 14-digit HUC basins (Bower and 

others, 1999), which range in size from 12.1 km2 to 

162 km2 , or the 8-digit HUC basins (Seaber and others, 

1987), which generally exceed 1,810 km2, for intakes 

having larger secondary source-water protection areas. 

The smaller drainage area size of the 14-digit HUC 

basins provided greater definition of the primary

Table 2. Surface-water intakes and drainage areas in 

South Carolina with only primary source-water protection 

areas, 1999

[HUC, Hydrologic Unit Code; DA, drainage area; km2 , square kilometer]

Intake no.

(fig. 1)

i S10103

S11101

S13102

S 13103

S20101

|_S20104

S23101

S23102

S28101

I S29104

S30101

S30102

S30103

S30106

S32103

S32104

S32105

S34101

S35102

S37102

S37103

S39103

S39104

S39105

S421.02

S42103

S46101

S46102

S46103

14-digit HUC basin3

03050201070010°

03050 105 11 00 10b

03040202060010"

03040201100010°

03050106080010°

03050106080020°

03050109010010

03050109020010°

03050 1040700206

03040202070030°

03050109160010°

03050109130030° 

03050109130010 

03050109130020

03050108040010°

03050109130030° 

03050109130010 

03050109130020

03050109210040° 

03050109210030

03050203010020°

0305020301 00 10b

03040201070010

030601 070 10090b

03060101080010

03060102120030°

03060101060020°

03060101060010d 

0306010 1060020d

03060101090010b

03050105150010b

03050 1051 500 10b

03050103010010°

030501 060200 10b

03050106020010°

HUC basin DA Intake DA 

(km2) (km2)

156

60.4

108

124

99.3

52.6

65.8

142

90.6

81.7

78.5

103 

93.6 

134 

Total intake DA =

105

103 

93.6 

134 

Total intake DA =

44.8 

80.7 

Total intake DA

94.5

111

149

68.8

45.8

97.9

39.9

48.4 

39.9 

Total intake DA

89.7

18.6

1.8.6

118

84.3

84.3

116°

38.2C

16.8C

«. 4.74C 

20.6C

4.33C

65.8

39. l c

19.6C

37.4C

21.8C

1 .84C 

93.6 

134 

= 229

43.5 C

0.44C 

93.6 

134 

= 228

5.23 C 

80.7 

= 85.9

59.3 C

3.78C

149 |

38.6C

45.8 _J

16.3 C

39.0U |

48.4 i 

39.9 

= 88.3

25.8C

13.6C

].86C

20.8C

2.05C

14.6C

aBower and others, 1999.

Intake lies within 14-digit HUC basin.

cDrainage area from the intake to the upstream boundary of the 

basin that contains the intake.

Intake lies at intersection of two 14-digit HUC basins.

source-water protection area thereby reducing the time 

for inventory of potential contaminant sources within 

the primary source-water protection area. The 8-digit 

HUC basins were used for intakes where the secondary

Intakes with Primary and Secondary Source-Water Protection Areas 11
source-water protection area encompassed the entire 

8-digit HUC basin. By using 8-digit HUC basins for 

such an intake, the table used to identify the secondary 

source-water protection areas was reduced in size.

Determination of the 24-hour Travel Time 

Distance

The travel distance methods (T.H. Lanier and 

W.F. Falls, U.S. Geological Survey, written commun., 

1998) were applied to 40 intakes in South Carolina, 

which include the 3 pilot project intakes, to determine 

the 24-hr travel distance that is used to delineate 

primary and secondary source-water protection areas. 

If an intake lay within a reservoir, the 24-hr travel 

distance from the headwaters was computed by using 

the 10-percent exceedance flow on all major streams 

and tributaries that entered the reservoir. Several 

intakes were located near neighboring State 

boundaries; therefore, the 24-hr travel distance was 

computed into these neighboring States. Including the 

29 intakes with only primary source-water protection 

areas, these methods were successfully applied to 69 

intakes, thereby verifying the methods.

Five intakes along the South Carolina coast are 

located in tidal rivers or tidal reservoirs. Travel 

distances could not be determined by using the 

methods of Lanier and Falls (1999). Therefore, 

dynamic flow models were used to estimate the travel 

distances. These tidally influenced sites are located on 

the Waccamaw River (intake S22102), Atlantic 

Intracoastal Waterway (S26101), Bull Creek (S26102), 

Foster Creek (S10102), and Bushy Park Reservoir 

(S10104) (fig. 4). For the intakes located on the 

Waccamaw River, Atlantic Intracoastal Waterway, and 

Bull Creek (fig. 4A), one-dimensional dynamic flow 

and transport models (Drewes and Conrads, 1995) 

were used to simulate the transport of a contaminant for 

selected flow conditions. For intakes located on Foster 

Creek and Bushy Park Reservoir (fig. 4B), a onedimensional model described by Bower and others 

(1993) was used to simulate particle tracking for 

selected flow conditions.

The following procedures were used to 

determine the 24-hr travel distance for the Waccamaw 

River, Atlantic Intracoastal Waterway, and Bull Creek 

intakes.

1. Concurrent flow periods near the 10-, 50-, and 

90-percent exceedance flows for the upstream

boundaries (Pee Dee River at Route U.S. 701 and 

Waccamaw River at Route U.S. 501 Bypass) were 

selected from the 1990-94 water years (Bennett and 

others, 1990-93; Cooney and others, 1994). A water 

year is the 12-month period from October 1 through 

September 30 of the following year, and is identified by 

the calendar year in which it ends.

2. The flow periods were simulated using the 

BRANCH unsteady flow model (Schaffranek and 

others, 1981). Simulations were begun 3 days prior to 

the flow periods of interest so the model would 

stabilize before final computations were made.

3. The flow field data simulated by the BRANCH 

model were converted to the flow field for the 

Branched Langrangian Transport Model (BLTM) 

(Jobson and Schoellhamer, 1987). Flows at 15-minute 

time steps of the BRANCH model were averaged to 

produce 60-minute time-step flows for the BLTM. 

Non-branching internal junctions were removed in the 

conversion to the BLTM.

4. The BLTM was used to simulate a slug of 

contaminant injected at the upstream boundaries of the 

model. For the low-flow (90-percent exceedance) 

simulation, a slug of contaminant also was injected at 

the downstream boundary. During low-flow periods, 

the net streamflow can be upstream due to reversing 

flows in tidal reaches.

5. The location of the 24-hr travel distance was 

determined by analyzing the output from the BLTM. A 

post-processing program was used to generate time 

series of concentrations at the intakes and selected 

upstream locations.

6. The time of peak concentration at the intake was 

determined, and then the location of the peak 

concentration in the previous 24 hrs was determined.

For the intakes on Foster Creek and Bushy Park 

Reservoir (fig. 4B), the particle-tracking utility of the 

BRANCH model was used to simulate the advection of 

particles. The schematization of the model is described 

in Bower and others (1993). The flow periods selected 

for this analysis are near the 10-, 50-, and 90-percent 

exceedance flows from the Pinopolis Dam on the West 

Branch of the Cooper River (fig. 4B). The flow rate of 

the Foster Creek intake for the simulation period was 

used. However, the Bushy Park Reservoir intake was 

not online during the period of the data base, so no flow 

rates were available for this intake.

A particle was released 1.61 km downstream 

from the Foster Creek and Bushy Park Reservoir

12 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
(A)

 Surface-water intake 

526102 and intake number

2j) Interstate highway 

@ U.S. highway

 Surface-water intake 

S26102 and intake number

(B)

Figure 4. Locations of surface-water 

intakes on (A) the Waccamaw River, 

Atlantic Intracoastal Waterway, and Bull 

Creek; and (B) Foster Creek and Bushy 

Park Reservoir, South Carolina.

Intakes with Primary and Secondary Source-Water Protection Areas 13
intakes for the low-flow simulation period of July 28- 

August 9, 1993 (Bennett and others, 1993). It took 

approximately 50 hrs for the particle located 

downstream from the Foster Creek intake to move 

upstream toward the intake. The particle located 

downstream from the Bushy Park Reservoir intake did 

not reach the intake during the simulation period. The 

flow rate of the Foster Creek intake was then set to zero 

to evaluate the sensitivity of particle advection to flow 

rate. At a flow rate of zero, the particle took 

approximately 210 hrs to move 4.83 km downstream to 

the confluence with the Back River. Intermediate- and 

high-flow periods were evaluated with similar results.

These results indicate that the flows at the 

intakes in Foster Creek and the Bushy Park Reservoir 

were not affected by the flows of the Cooper River, but 

were strongly affected by the intake flow rates. 

Although the water levels of Foster Creek and the 

lower reach of Bushy Park Reservoir are tidally 

influenced, the flows in the system also are influenced 

by other factors such as wind-driven currents (Bower 

and others, 1993). Rainfall events affect the flows in 

the headwaters of Foster Creek, and tidal exchange 

with Durham Canal affects the flows in the upper reach 

of Bushy Park Reservoir. Therefore, the primary 

source-water protection area for the Foster Creek 

(SI0102) intake and the Bushy Park Reservoir 

(SI0104) intake will be the 14-digit HUC's that include 

Foster Creek and Bushy Park Reservoir.

The 24-hr travel time distance was computed for 

45 intakes in South Carolina, of which 3 intakes were 

analyzed as part of the 1998 pilot project. The results of 

the computations are listed in table 3 (p. 16).

Determination of Primary and Secondary 

Source-Water Protection Areas

The primary source-water protection area for an 

intake encompasses all 14-digit HUC basins adjoining 

the stream within the computed 24-hr (10-percent 

exceedance flow) travel distance upstream from the 

intake. If an intake is located on any part of a reservoir, 

the primary source-water protection area for the 

reservoir intake includes all 14-digit HUC basins 

adjoining the reservoir and the feeder streams within a 

24-hr travel distance upstream from the headwaters of 

the reservoir. The primary source-water protection area 

is limited to the base of the upstream reservoir's dam 

(D. Baize, South Carolina Department of Health and 

Environmental Control, oral commun., July 1999) if

the primary source-water protection area of an intake 

extends into one of the following lakes: Blewett Falls, 

Greenwood, Hartwell, Jocassee, Keowee, Marion, 

Moultrie, Murray, Norman, Richard B. Russell, J. 

Strom Thurmond, Wateree, Wylie, or Fishing Creek 

Reservoir (fig. 2). If the drainage basin for an intake is 

larger than the primary source-water protection area, 

the remaining drainage area upstream from the primary 

source-water protection area is designated as the 

secondary source-water protection area. Table 4 (p. 20) 

lists the primary and secondary source-water protection 

areas for 45 intakes, of which 3 intakes were analyzed 

as part of the 1998 pilot project.

SUMMARY

In a 1998 pilot project, the U.S. Geological 

Survey, in cooperation with the South Carolina 

Department of Health and Environmental Control, 

developed methods to determine in-stream travel 

distance and the primary and secondary source-water 

protection areas for surface-water intakes in South 

Carolina. These methods were applied to three intakes 

in South Carolina. In June 1999, the U.S. Geological 

Survey entered into a cooperative agreement with the 

South Carolina Department of Health and 

Environmental Control to verify the statewide 

applicability of the source-water protection methods 

previously developed. These methods were 

successfully applied to 69 intakes in South Carolina, 

thereby verifying the methods.

The 24-hour distance for the 10-, 50-, and 90- 

percent exceedance flow was determined on the main 

streams and tributaries upstream from all intakes with 

drainage areas that are estimated to have more than 24 

hours of in-stream travel time between the intake and 

the 14-digit Hydrologic Unit Code basins in the 

headwaters of the drainage basin. The 24-hour travel 

distance from an intake computed for the 10-percent 

exceedance flow is the primary travel distance used to 

segment the primary and secondary source-water 

protection areas. All 14-digit Hydrologic Unit Code 

basins that adjoin the surface-water flow system 

between an intake and the upstream 10-percent 

exceedance, 24-hour travel distance were designated as 

the primary source-water protection area for that 

intake. The remainder of the source-water protection 

area upstream from the primary source-water 

protection area was designated as the secondary 

source-water protection area. For this study, the effect

14 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
of reservoirs with volumes less than that of Fishing 

Creek Reservoir was not included in the calculation of 

the primary travel distance. However, for intakes with 

primary travel times that extended into larger 

reservoirs, the base of the larger reservoir's dam was 

the upstream limit of the primary source-water 

protection area. The 24-hour distance and the primary 

and secondary source-water protection areas were 

determined for 45 intakes in South Carolina.

Some of the surface-water intakes in South 

Carolina have drainage areas that are equal to or less 

than one 14-digit Hydrologic Unit Code basin, or are 

estimated to have less than 24-hours of in-stream travel 

time between the intake and the 14-digit Hydrologic 

Unit Code basin(s) in the headwaters of the drainage 

basin. For such an intake, the entire drainage area is 

designated as the primary source-water protection area 

and the 24-hour travel distance does not have to be 

determined. Twenty-nine intakes meet these criteria 

and the 24-hour travel distance was not calculated.

The source-water protection methods were not 

applicable for the Waccamaw River, Atlantic 

Intracoastal Waterway, Bull Creek, Foster Creek, and 

Bushy Park Reservoir intakes because these intakes are 

located along the South Carolina coast and are tidally 

influenced. Therefore, the 24-hour distance and the 

primary and secondary source-water protection areas 

for these five intakes were determined by using onedimensional dynamic flow and transport models.

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SC-91-l,465p.

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Ragland, B.C., Smith, D.G., Barker, R.G., and Robinson, J.B., 

1998, Water resources data, North Carolina, water year 

1998: U.S. Geological Survey Water-Data Report 

NC-98-l.v. 1,690 p.

Schaffranek, R.W., Baltzer, R.A., and Goldberg, D.E., 1981, A 

model for simulation of flow in singular and interconnected channels: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 7, chap. C3, 110 p.

Seaber, PR., Kapinos, P.P., and Knapp, G.L., 1987, Hydrologic 

unit maps: U.S. Geological Survey Water-Supply Paper 

2294, 63 p.

South Carolina Department of Health and Environmental

Control, 1999, South Carolina Source Water Assessment 

and Protection Program: Columbia, S.C., Final Draft 

Approved by Citizens and Technical Advisory Committee 

for Public Comment, February 1999, 85 p.

Stokes, W.R., III, and McFarlane, R.D., 1998, Water resources 

data, Georgia, water year 1998: U.S. Geological Survey 

Water-Data Report GA-98-1, 668 p.

U.S. Water Resources Council, 1981, Guidelines for determining flood-flow frequency: U.S. Water Resources Council 

Bulletin 17B, 28p.

Selected References 15
Table 3. Twenty-four-hour travel distances for surface-water intakes in South Carolina, 1999

[TOT 10, TOT50, and TOT90, time of travel for 10-, 50-, and 90-percent exceedance flows, respectively; RK, river kilometer; EB, entire basin 

affected; NE, no effect; NC, not calculated]

Intake 

no.

(fig. 1)

SOI 101

S02101

S02103

S02105

S04101

S04105

S07101

SOS 104

S10101

S10102d

S10104d

SI 1102

S12101

S13101

Stream

Rocky River3

Beaverdam Creek3

Coldwater Creek3

Big Generostee Creek3

Shaw Creekb

Paces Branch0

Savannah River

Stevens Creekc

Horn Creekc

Turkey Creekc

Kiokee Creekc

Horse Creekb

Three and Twenty Creek3

Eighteen Mile Creek3

Twelve Mile Creek3

Coneross Creek3

Chauga River3

Tugaloo River3

Tallulah Riverc

Stekoa Creekc

Warwoman Creek0

West Fork Chattoogac

Saluda Riverb

Big Creekc

Grove Creekc

Hurricane Creekc

Brushy Creekc

Middle Branch0

Georges Creek0

Savannah Riverb

Cypress Creek0

Clear Water Creek0

Ebenezer Creek0

Lake Moultrie3

Edisto Riverb

Fourhole Swamp0

Dean Swamp0

Indianfield Swamp0

Cattle Creekc

Foster Creek

Bushy Park Reservoir

Broad Riverb

First Broad River0

Sandy Run Creek0

Second Broad River0

Green River0

Catawba Riverb

Twelve Mile Creek0

Sugar Creek0

McAlpine Creek0

Great Pee Dee Riverb

S. Fork Jones Creek0

Hitchcock Creek0

24-hour TOT-, 0 24-hour TOT50 24-hour TOT90 

point (RK) point (RK) point (RK)

35.7

EB

EB

EB

43.8

3.8

23.5

EB

EB

EB

41.2

1.8

17.2

EB

EB

EB

39.0

NE

J. Strom Thurmond Dam (J. Strom Thurmond Lake)

54.0

26.1

15.5

26.4

EB

EB

EB

39.8

34.0

44.3

61.4

45.4

26.0

8.8

1.0

135.7

EB

EB

EB

14.8

5.5

3.9

86.1

34.3

2.4

35.9

62.8

48.5

9.9

23.8

4.5

NC

NC

117.6

40.2

26.8

29.3

5.5

27.5

13.7

NE

14.3

EB

EB

EB

31.2

26.5

33.7

45.2

29.6

15.7

NE

NE

120.1

17.2

17.0

8.5

5.1

NE

NE

54.3

14.6

NE

10.1

Santee Dam (Lake Marion)

35.5

19.3

NE

7.0

NE

NC

NC

103.5

26.8

18.2

16.4

NE

Catawba Dam (Lake Wylie)

28.4

24.8

10.3

12.9

9.3

NE

Blewett Falls Dam (Blewett Falls Lake)

24.8

23.4

13.2

10.3

18.1

5.6

NE

9.8

EB

EB

EB

25.0

22.3

25.8

32.5

17.5

6.3

NE

NE

109.6

13.5

11.7

3.0

NE

NE

NE

43.2

3.9

NE

2.4

22.7

8.6

NE

1.1

NE

NC

NC

93.4

19.7

11.8

8.1

NE

29.4

4.5

NE

NE

31.4

4.6

1.4

16 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
Table 3. Twenty-four-hour travel distances for surface-water intakes in South Carolina, 1999--Continued

[TOT 10, TOT50, and TOT90, time of travel for 10-, 50-, and 90-percent exceedance flows, respectively; RK, river kilometer; EB, entire basin 

affected; NE, no effect; NC, not calculated]

no.

(fig.1)

S13104

SI 31 05

S19101

S22101

S22102d

S23103

S23104

S24101

S26101 d

S26102d

S28102

S29106

S301 04

S32101

S32102

Oil Of roam edl 1 1

Thompson Creek"

Lynches River5

Savannah River5

Stevens Creek0

Horn Creek0

Turkey Creek0

Kiokee Creek0

Great Pee Dee River5

Lynches River0

Singleton Swamp0

Catfish Creek0

Jefferies Creek0

Waccamaw River/Bull Creek/Pee Dee River

Waccamaw River

Great Pee Dee River0

Flat Shoals River3

South Tyger River

Cane Creek3

Long Lick Branch3

Mulberry Creek3

Turkey Creek3

Rabon Creek3

North Rabon Creek0

South Rabon Creekc

Reedy River3

Walnut Creek0

Horse Creek0

Saluda River3

Broad Mouth Creek0

Mountain Creek0

Big Creek0

Hurricane Creek0

Grove Creek0

Atlantic Intracoastal Waterway/Waccamaw River

Atlantic Intracoastal Waterway5

Bull Creek/Little Pee Dee River5

Great Pee Dee River0

Lynches River0

Singleton Swamp0

Catfish Creek0

Little Wateree Creek3

Catawba River3

Rocky Creek0

Fishing Creek0

South Fork Fishing Creek0

Catawba River5

Twelve Mile Creek0

Sugar Creek0

McAlpine Creek0

Enoree River

Congaree Creek5

Saluda River5

Twelve Mile Creek0

24-hou r TOT! 0 24-hou r TOT50

point (RK)

EB

EB

point (RK)

EB

EB

24-hour TOT90

point (RK)

EB

EB

J. Strom Thurmond Dam (J. Strom Thurmond Lake)

58.6

28.7

20.1

EB

100.7

38.4

17.6

13.3

7.0

39.6

NE

1.5

EB

EB

EB

EB

EB

EB

EB

18.2

18.2

55.8

EB

11.9

106.1

20.8

15.9

10.0

0.4

8.7

21.7

NE

62.8

70.2

17.9

4.2

0.5

EB

31.2

17.1

NE

EB

65.0

13.5

NE

NE

NE

16.6

NE

NE

EB

EB

EB

EB

EB

24.8

EB

10.0

9.7

41.3

EB

2.9

88.6

12.7

8.7

NE

NE

NE

11.3

NE

47.2

37.8

NE

NE

NE

EB

20.5

9.0

NE

EB41.1 ~"~~ '

2.1

NE

NE

NE

10.0

12.6e

NE

EB

EB

EB

EB

EB

20.3

EB

3.7

3.7

31.1

11.7

NE

78.1

6.4

2.6

NE

NE

NE

9.3

6.0f

20.9

13.2

NE

NE

NE

EB

Fishing Creek Dam (Fishing Creek Reservoir)

39.6

42.8

2.9

21.9

21.2

NE

Catawba Dam (Lake Wylie)

35.1

33.7

18.5

89.6

EB

EB

19.2

16.6

1.3

74. 1

EB

Saluda Dam (Lake Murray)

EB

14.6

12.7

NE

28.3

12.1

7.8

NE

65.8

EB ~]

EB

Twenty-Four Hour Travel Distances 17
Table 3. Twenty-four-hour travel distances for surface-water intakes in South Carolina, 1999-Continued

[TOT 10 , TOT50, and TOT90, time of travel for 10-, 50-, and 90-percent exceedance flows, respectively; RK, river kilometer; EB, entire basin 

affected; NE, no effect; NC, not calculated]

Intake 

no.

(fig. 1)

S32107

S35101

S36101

S36102

S36103

S37101

S37104

S38101

S39101

S39106

S40101

S40102

S42101

S42104

S44101

Stream

Little Saluda River3 

Clouds Creek3 

Bush River3 

Saluda River3 

Little Riverc 

Ninety Six Creek0 

Wilson Creekc

Long Cane Creek3 

Little River (South Carolina)3 

Calhoun Creek3 

Middle Creek3 

Little River (Georgia)3 

Fishing Creek3 

Broad River3 

Long Creekc 

South Fork Broad Riverc

Saluda Riverb 

Little River0 

Ninety Six Creek0 

Wilson Creek0

Enoree River"

Duncan Creekb

Flat Shoals River3

Chauga Riverb

North Edisto Riverb 

Bull Swamp Creek0

Saluda Riverb 

North Saluda River0 

South Saluda River0

Twelve Mile Creek

Broad Riverb 

Little River0 

Cannons Creek0 

Enoree River0 

Tyger River0

Little Saluda River3 

Clouds Creek3 

Bush River3 

Saluda River3 

Little River0 

Ninety Six Creekc 

Wilson Creek0

South Pacolet Riverb

Middle Tyger River

Broad Riverb 

Turkey Creek0 

Pacolet Riverc 

Bullock Creek0 

Thicketty Creek0 

Kings Creek0 

Buffalo Creek0

24-hour TOT10 

point (RK)

24-hour TOT50 

point (RK)

EB EB 

EB EB 

33.0 18.6 

Buzzard Roost Dam (Lake Greenwood) 

33.0 18.9 

13.3 2.6 

11.0 NE

41.7 

44.8 

24.5 

EB 

46.5 

EB 

.59.2 

40.0 

18.0

26.3 

27.9 

12.1 

EB 

24.9 

EB 

39.2 

26.3 

0.6

Buzzard Roost Dam (Lake Greenwood) 

33.7 19.6 

13.9 3.3 

11.9 NE

49.9

41.9

EB

40.6

43.6 

14.9

44.9 

29.6 

20.7

37.6

77.2 

30.6 

EB 

10.1 

5.1

33.7

31.5

EB

32.7

32.0 

6.6

35.6 

22.6 

10.7

29.5

52.9 

12.3 

EB

NE 

NE

EB EB 

EB EB

33.0 18.6 

Buzzard Roost Dam (Lake Greenwood) 

33.0 18.9 

13.3 2.6 

11.0 NE

EB

EB

70.5 

32.4 

38.0 

25.5 

26.3 

16.2 

9.2

EB

EB

49.0 

22.6 

23.1 

15.6

NC 

4.3

NE

24-hour TOT90 

point (RK)

EB 

EB

12.1 

22.8 

10.9

NE 

NE

19.0 

20.2 

6.2 

EB 

16.4 

EB 

28.5 

19.3 

NE

24.2 

11.6

NE

NE

21.6

22.8

EB

24.9

24.6 

1.0

29.4 

15.3 

3.8

24.9

38.5 

5.5 

EB

NE 

NE

EB 

EB

12:1 

22.8 

10.9

NE 

NE

EB

EB

36.2 

15.8 

13.8 

8.1

NC 

NE 

NE

18 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
Table 3. Twenty-four-hour travel distances for surface-water intakes in South Carolina, 1999--Continued

[TOTiQ, TOT50, and TOTgg, time of travel for 10-, 50-, and 90-percent exceedance flows, respectively; RK, river kilometer; EB, entire basin 

affected; NE, no effect; NC, not calculated]

Intake 

no.

(fig. 1)

| S46109

!

Stream

Catawba River3 

South Fork Catawbac 

Clark Creekc 

Dutchmans Creekc

24-hour TOT10 

point (RK)

24-hour TOT50 

point (RK)

Cowans Ford Dam (Lake Norman) 

51.4 35.9 

7.7 NE 

EB EB

24-hour TOT90 

point (RK)

27.8 

27.6 

NE 

EB

aRK zero is at the headwaters of the lake.

bRK zero is at the intake.

C RK zero is at the confluence with receiving stream.

Tidally influenced intake. 

Southwestern direction resulting from flow reversal/tidal conditions.

Northeastern direction resulting from flow reversal/tidal conditions.

Twenty-Four Hour Travel Distances 19
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

Intake 

no.

(fig. 1)

S01101

"S02103~~

..:,.

S04101

: : : ,;

;- :

. » * .," '

S04W5

-'::::«::;. -***» 

-;;;i:i; -

Primary SWPA

Intake DAa HUC 

(km2) 14-digit HUC basins basin DA 

(km2)

7,470 03060103030.010-130.. 996 

;:;- 0306010304^010-030;;: 31ft:* 

03060103070 010 - 050 507

03060103080 010 230

. ; : : . ; ; , . Total Primary DA = 2,05 0:

:t::r ' 03050204020; 020 ' : ':>' *93l0fc:"

1 8,500 03060 1 06030 0 1 0 - 05:0 : 66 1 : : ' 

03060106050010 " 65.4C 

03060107010080 61.5 

:: 03060107010100 ; 38.8

**:r 03060107020040 :;; 126*

03060107020080 28.7

03060107030010 113.0

::; 03:0601070400 10- 070; : 532:::

Total primary DA = 1,630

 ;; :m , ., :0|p60 1060,6.0 m o - 02Q::; ., . .134:::: .

: ff""' 'r'f:*' Tottl primary DA = 155:!:>

5,420 03060101040010-070 546 

03060101060010-060;; 275:,

;: 03060101070010-020! 126'

03060101080010-020 194

03060101090010-020, 154

: ; : : 03060 1 0 1 1 00 01 0 - 020: : 239 : : :

03060102010010 172

03060102010030 35.0

03060102060,010-080., 739;;

:: 03060 102070:030- 080 :: 362"

03060102120010-040 286

03060102130010-070, 727 ,

 -'-' 03060103020010 ::: . 202;»:-

Total primary DA = 4,060

1 ,240 03050 1 09040020 - 050; ; 248, ; ,

: : : ; ' -'-:

' !: : ;: ^ 05050109070%10 '":"'' 50Sr

; ;;h.. .,030^)109080*10 ,:::::, 40jS: ;>

Secondary SWPA

HUC basins

03060101° 

03060102° : ;- :r 

03060103020010

; Total secondary DA

N^:;::- °:::;::r -^" 

03060101" ,: : ; 

03060102° : 

03060 103b 

03060104b :: , ;> .

03060l05b ''.':' "'"'

03060107010010-070

03060107010090

03060107020010-030 .,<!

03060107020 050 - 070

Total secondary DA =

HUC

basin DA 

(km2)

2,640 

:2,580 

202

= 5^420

; 2;640 

2,580 

4,740 

;3,880 

' : I;980

475

68.8

--,'.'2.86 -

186

= 16,800

*tlf:: li§

03060101010010-030 

03060101020 0:1:0 ::..

03060101030010-030

03060101050010-050

03060102010020

03060102070010-020 " '*' 

: : ; .; - . . - > 

Total secondary DA

03050109010010-020 .:;..

;lo^lSllll?"3 -*«i^ : : :

030501 09040 6«T ".^''

250

"319

425

»:113 ' ::: :128 '

= 1,360

;;196

: :l||f:: ^

4:;l21

- .: ::;::::: "iH^^l DK=I$6Q :':';

20 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999--Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

Intake Primary SWPA lntQk° Intake DAa 

na (km2) 14-digit HUC basins

S07101 26,400 03060109020010 

03060109020030-040 

03060109020 060 - 070 

03060109030020-030 

03060109050 010 

03060109060010 

03060109060020-050

Total primary DA =

SOS 104 38,200 03050201010010-020 

03050201010 030

Total primary DA

S10101 7,050 03050205010040 

03050205020 020 

03050205030 010 - 020 

03050205040010-040 

! 03050205050 010 

i 03050205060 010 

i 03050206040010 

03050206040 040 - 050 

03050206060010-040 

03050206070010-040 

Total primary DA =

S10102 IND 03050201060010-020 

Total primary DA

HUC 

basin DA 

(km2 )

236 

206 

148 

386 

38.0 

79.3C 

314

1,410

230 

86.0C

= 316

103 

84.4 

188 

413 

40.7 

6.34C 

105 

99.4 

270 

319 

1,630

199 

= 199

Secondary SWPA

HUC 

HUC basins basin DA 

(km2)

03060101° 2,640 

03060102b 2,580 

03060103b 4,740 

03060 104b 3,880 

03060105b 1,980 

03060106b 4,750 

03060 107b 1,920 

03060108b 2,200 

03060109020020 43.5 

03060109020050 132 

03060109030010 124 

Total secondary DA = 25,000

03050101 b 6,100 

03050102b 1,700 

03050103b 3,550 

03050104° 3,130 

03050105b 6,420 

03050106° 3,340 

03050 107b 2,100 

03050108° 1,890 

03050109b 6,420 

03050 H0b 1,830 

03050111 b 1,410 

Total secondary DA = 37,900

03050203b 1,970 

03050204° 2,240 

03050205010010-030 225 

03050205020010 85.9 

03050206010010-020 208 

03050206020010-040 294 

03050206030010-020 176 

03050206040020-030 64.9 

03050206050010-020 156

Total secondary DA = 5,420 ;

03050101 b 6,100 

03050 102b 1,700 

03050103° 3,550 

03050104b 3,130 

03050 105b 6,420 

03050106b 3,340 

03050107b 2,100 

03050 108° 1,890 

03050109b 6,420 

030501 10b 1,830 

03050111° 1,410 

03050201030010 146 

03050201010010-030 355 

03050201020010-040 328 

Total secondary DA = 38,700

Primary and Secondary Source-Water Protection Areas 21
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999-Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

Intake

no.

(fig.1)

S10104

SI 1102

S12101

S13101

S13104

SI 3 105

Primary SWPA

Intake DAa HUC

(km2) 14-digit HUC basins basin DA

(km2)

IND 03050201060010-020 199

Total primary DA = 199

3,360 03050105020 040 97.6

03050105030 010 137

03050105040090 63.1

03050105050010-040 334

03050105070 030 90.3

03050105070 050 - 080 256

03050105080 060 - 070 207

03050105080090-110 166

03050105090010 59.1 C

Total primary DA = 1,410

9,370 03050103010010-030 279

03050103010040 58.2C

03050103020010-050 570

03050103020080 54.9

03050103030010-030 518

Total primary DA = 1 ,480

18,900 03040201010010-100 1028

03040201020010 68.5

03040201030010 83.2

03040201040010 80.2

03040201050010 37.2C

Total primary DA = 1,300

382 03040201060010 108

03040201060015 81.3

03040201060020-040 183

03040201060050 10.0C

Total primary DA = 382

452 03040202010010 132

03040202020 010 60.6

03040202030 010 - 020 129

03040202040010 126

03040202050010 4.14C

Total primary DA = 452

Secondary SWPA

HUC basins

03050101"

03050102b

03050103b

03050 104b

03050105b

03050106b

03050107b

03050108b

03050109b

030501 10b

03050111 b

03050201030 010

03050201010010-030

03050201020010-040

Total secondary DA =

03050105010010

03050105020010-030

03050105040 010 - 080

03050105060010-020

03050105070010-020

03050105070040

03050105080 010 - 050

Total secondary DA =

03050101 b

03050 102b

03050103020 060 - 070

Total secondary DA =

03040101 b

03040 102b

03040103b

03040104b

03040105b

Total secondary DA =

HUC

basin DA

(km2)

6,100

1,700

3,550

3,130

6,420

3,340

2,100

1,890

6,420

1,830

1,410

146

355

328

38,700

110

290

662

117

232

67.6

467

= 1,950

6,100

1,700

87.6

= 7,890

6,270

2,370

3,060

2,230

3,680

17,600

N/A

N/A

22 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999--Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

Intake Primary SWPA lntaKc Intake DAa 

na (km2) 14-digit HUC basins

S19101 18,400 03060106030010-050

03060106050010

03060107010080-100

03060107020040

03060107020080

03060107030010

03060107040010-070

Total primary DA =

S22101 28,200 03040201120030

03040201130030

03040201140010-030

03040201150050

03040201160010-030

03040201160040

03040202120030-040

03040202130010

03040202170010

Total primary DA =

HUC 

basin DA 

(km2)

661

5.44C

169

126

28.7

113

532

1,640

60.0

76.3

237

114

241

123C

216

154

94.7

1,320

Secondary SWPA

HUC basins

03060101°

03060102°

03060103°

03060104°

03060105°

03060107010010-070

03060107020010-030

030601 07020 050 - 070

Total secondary DA =

03040201010010-100

03040201020010

03040201030 010

03040201040010

03040201050010- 100

03040201060 010 - 100

03040201070010-020

03040201080010-020

03040201090010-040

03040201100010-050

03040201110010- 100

03040201120010-020

03040201130010-020

03040201130040-060

03040201150010-040

03040202010010

03040202020010

03040202030010-020

03040202040010

03040202050 010 - 060

03040202060010

03040202070010-040

03040202080010-020

03040202090 010 - 060

03040202100010-070

03040202110010-020

03040202120010-020

03040202140010

03040202150010

03040202160010

03040101°

03040102°

03040103°

03040104°

03040105°

Total secondary DA =

HUC 

basin DA 

(km2 )

2,640

2,580

4,740

3,880

1,980

475

286

186

16,800

1,028

68.5

83.2

80.2

913

897

201

180

322

442

756

281

257

221

337

132

60.5

129

126

480

108

352

161

513

436

1.41

224

80.3

104

146

6,270

2,370

3,060

2,230

3,680

26,900

Primary and Secondary Source-Water Protection Areas 23
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999--Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

Intake Primary SWPA

lntaKe Intake DAa HUC 

J10'. (km2) 14-diqit HUC basins basin DA 

(fig ' 1) (km2)

1 S22102 IND 03040201160040 155 

03040201170010-030 302 

03040204070 060 88.4 

^ 03040206150010-030 218

i i

1

j

j

j

i 

i

i

;

|

i

1

1

Total primary DA = 763 /

Secondary SWPA

HUC basins

03040101° 

03040 102b 

03040103° 

03040104° 

03040 105b

03040201010010-100

03040201020 010

03040201030010

03040201040 010

03040201050010-100

03040201060010-100

03040201070010-020

03040201080010-020

03040201090010-040

03040201100010-050

03040201110010-100

03040201120010-030

03040201130010-060

03040201140010-030

03040201150010-050

03040201160010-030 

03040202° 

03040203°

03040204010010-070

03040204020010-030

03040204030 010-070

03040204040 010-040

03040204048 010

03040204050010-040

03040204060 010

03040204070010-050

03040204070 070

03040204080 010 - 060

03040204081 010

03040204090010-020

03040206010010-070

03040206020010-040

03040206030010

03040206040 010

03040206050010

03040206060010-060

03040206090010-030

03040206100010

03040206102 010

03040206110010

03040206120 010 - 050

03040206130010-030

03040206140010-030

03040207020130-150

Total secondary DA =

HUC 

basin DA 

(km2)

6,270 

2,370 

3,060 

2,230 

3,680

1,028

68.5

83.2

80.2

913

897

201

180

322

442

756

341

555

237

451

241 

3,600 

4,530

480

193

483

330

87.7

395

54.8

543

91.4

563

7.88

215

827

202

172

48.1

24.5

589

307

91.9

52.0

137

228

338

322

144

= 39,500

24 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999--Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

no.

(fig.1)

S23103

S23104

S24101

S26101

!

S26102

Primary SWPA

Intake DAa HUC 

(km2) 14-digit HUC basins basin DA 

(km2)

1,120 030601010300.10-030 319

03060101050010-050 425

Total primary DA = 744

170 03050107010010 123

03050107010020 47.4

Total primary DA = 1 70

3,020 030501 09040 020 - 050 248 

03050109070010 50.7

03050109080010-090 688

03050109090010-020 88.2

03050109120010-040 284

03050109130010-030 330

Total primary DA = 1,690

IND 03040206140020-030 226

03040206150010 76.0

03040207020 150 68.7

Total primary DA = 371

IND 03040201140010-030 237 

03040201150050 114 

03040201160010-040 396 

03040201170010-020 162 

03040202120040 90.6

03040202170010 94.7 

03040204070 040 - 070 426

Secondary SWPA

HUC basins t

03060101010010-030

03060101020010

Total secondary DA

N/A

03050109010010-020 

03050109020010-030

03050109030010

03050109040010

03050109050 010

03050109060010-030

03050109100010-080

03050109110010

Total secondary DA =

03040206010010-070

03040206020010-040

03040206030 010

03040206040010

03040206050010

03040206060010-060

03040206090010-030

03040206100010

03040206102010

03040206110010

03040206120010-050

03040206130010-030

03040206140010

Total secondary DA =

03040101 b 

03040 102b 

03040103b 

03040 104b 

03040 105b

03040201010010- 100 

03040201020010

03040201030010

03040201040010

03040201050010-100

03040201060010-100

03040201070010-020

03040201080010-020

03040201090010-040

03040201100010-050

03040201110010-100

03040201120010-030

03040201130010-060

03040201150010-040

03040202010010

03040202020010

03040202030010-020

03040202040010

HUC 

jasin DA 

(km2)

250

129

= 379

196 

316

127

121

85.4

95.7

298

92.4

1,330

827

202

172

48.1

24.5

589

307

91.9

52.0

137

228

338

99.7

3,120

6,270 

2,370 

3,060 

2,230 

3,680

1,028 

68.5

83.2

80.2

913

897

201

180

322

442

756

341

555

337

132

60.5

129

126

Primary and Secondary Source-Water Protection Areas 25
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999-Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

Intake

no.

(fig-1)

Primary SWPA

Intake DAa HUC

(km2) 14-digit HUC basins basin DA

(km2)

Secondary SWPA

HUC basins

HUC

basin DA

(km2)

S26102 (Continued)

Total primary DA = 1,520

S28102

S29106

S30104

S32101

12,200 03050103010050 33.4

03050103060020 107

03050103060060-080 205

03050103070010 68.7

03050103080010 106

03050103090010-050 518

03050104010010-090 845

03050104020010 151

Total primary DA = 2,030

9,130 03050103010010-020 164

03050103010030 68.0C

03050103020010-050 570

03050103020 070 - 080 104

03050103030010-020 382

Total primary DA= 1,290

911 03050108010040 105

03050108010070-090 332

03050108020 010 52.5C

03050108020 020 37.8

03050108030 010 - 020 143

Total primary DA = 670

310 03050110020010-020 178

03050110020040-050 108

03050110020030 23.5C

Total primary D A = 3 1 0

03040202050010-060

03040202060010

03040202070 010 - 040

03040202080010-020

03040202090 010 - 060

03040202100010-070

03040202110010-020

03040202120010-030

03040202130010

03040202140010

03040202150010

03040202160010

03040203b

03040204010010-070

03040204020 010 - 030

03040204030010-070

03040204040 010 - 040

03040204048 0.10

03040204050010-040

03040204060 010

03040204070 010 - 030

03040204080010-060

03040204081 010

03040204090 010 - 020

Total secondary DA

03050101 b

03050 102b

03050103010010-040

03050103020010-080

03050103030010-030

03050103040010-060

03050103050010

03050103060010

03050103060 030 - 050

Total secondary DA

03050101 b

03050 102b

03050103020060

480

108

352

161

513

436

141

349

154

80.3

104

146

4,530

480

193

483

330

87.7

395

54.8

297

563

7.88

215

= 34,900

6,100

1,700

393

708

518

424

129

76.9

162

= 10,200

6,100

1,700

38.4

Total secondary DA = 7,840

03050108010010-030

03050108010050-060

166

75.0

Total secondary DA = 241

N/A

26 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999--Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

Intake Primary SWPA lntake Intake DAa 

n°. (km2) 14-digit HUC basins

S32102 20,300 03050106010050

03050106050010-070

03050106060010- 100

03050106070 030

03050106070050

03050106080010-020

03050106090010-030

03050107050060-070

03050108050030

03050109210010-070

03050110010010

Total primary DA =

HUC 

basin DA 

(km2)

29.4

592

601

80.8

146

152

261

137

108

265

2.51 C

2,370

Secondary SWPA

HUC basins

03050105°

03050106010010-040

03050106020010-040

03050106030010

03050106040010-050

03050106070010-020

03050106070040

03050107010010-070

03050107020010

03050107030010-030

03050107040010-030

03050107050010-050

03050107060010-110

03050108010010-090

03050108020 010 - 050

03050108030010-020

03050108040010-040

03050108050010-020

03050108050040

03050109010010-020

03050109020010-030

03050109030010

03050109040010-050

03050109050010

03050109060010-030

03050109070010

03050109080010-090

03050109090010-020

03050109100010-080

03050109110010

03050109120010-040

03050109130010-030

03050109140010-040

03050109150010-080

03050109160010-090

03050109170010-060

03050109180010-020

03050109190010-090

03050109200010

Total secondary DA =

HUC 

basin DA 

(km2)

6,420

283

379

137

423

163

87.0

445

90.6

137

221

423

639

677

338

143

311

251

67.4

196

316

127

369

85.4

95.7

50.7

688

88.2

298

92.4

284

330

373

738

595

615

258

612

57

17,900

Primary and Secondary Source-Water Protection Areas 27
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999--Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

Intake Primary SWPA

lntaKe Intake DAa HUC

,,no' (km2) 14-digit HUC basins basin DA

(fig ' 1) (km2)

S32107 6,270 03050109140010 92.6

03050109140030-040 172

03050109150010-080 738

03050109160020 56.2

03050109160040-090 420

03050109170010-060 615

03050109180010-020 258

03050109190010-090 612

03050109200 010 57

Total primary DA = 3,020

S35101 15,900 03060103100010-100 1,170

03060103140030 90.0

03060103140070-130 486

03060103150020 69.3

03060103150040-100 416

03060104030 020 - 040 283

03060104040040-060 316

03060104050010-070 689

03060104060010-060 602

03060105010040-050 217

03060105020010-060 651

03060105030 010 - 030 296

03060105040 010-040 489

Total primary DA = 5,770

S36101 4,210 03050109140010 92.6

03050109140030-040 172

03050109150010-030 219

03050109150 080 4.35C

03050109160020 56.2

03050109160040-090 420

Total primary DA = 964

Secondary SWPA

HUC basins

03050109010010-020

03050109020 010 - 030

03050109030 010

03050109040010-050

03050109050 010

03050109060010-030

03050109070010

03050109080 010-090

03050109090010-020

03050109100010-080

03050109110010

03050109120 010 - 040

03050109130010-030

03050109140020

03050109160010

03050109160030

HUC

basin DA

(km2)

196

316

127

369

85.4

95.7

50.7

688

88.2

298

92.4

284

330

108

78.5

40.4

Total secondary DA = 3,250

03060 10 l b

03060 102b

03060103020 010

03060103030010-130

03060103040010-030

03060103070010-050

03060103080010

03060103140010-020

03060103140040-060

03060104010010-090

03060104020010-110

03060104030010

03060104040010-030

03060105010010-030

Total secondary DA

03050109010010-020

03050109020010-030

03050109030010

03050109040 010 - 050

03050109050010

03050109060 010 - 030

03050109070 010

03050109080010-090

03050109090 010 - 020

03050109100010-080

03050109110010

03050109120010-040

03050109130010-030

03050109.140020

03050109160010

03050109160030

2,640

2,580

202

996

319

507

230

166

138

782

798

106

320

336

= 10,100

196

316

127

369

85.4

95.7

50.7

688

88.2

298

92.4

284

330

108

78.5

40.4

Total secondary DA= 3,250

28 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999-Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; FND, indeterminate, flow tidally affected]

Intake 

no. 

(fig-1)

S36102

S36103

S37101

S37104

S38101

S39101

S39106

S40101

Primary SWPA

Intake DAa HUC 

(km2) 14-digit HUC basins basin DA 

(km2)

1,140 03050108020010 66.4 

03050108020030-040 104 

03050108020050 116C 

03050108030020 95.2 

Total primary DA = 3 82

295 03050108040010-020 213 

03050108040030 19.7C 

03050108040 040 62.6 

Total primary DA = 295

1,120 03060101030010-030 319 

03060101050010-050 425 

Total primary DA = 744

174 03060102120010-020 132 

03060102120030 41. 5C 

Total primary DA = 174

1,770 03050203040050-070 202 

03050203050020-040 172 

03050203060010-050 215 

03050203070010-020 208 

03050203080010 6.94C 

Total primary DA = 804

760 03050109010010-020 196 

03050109020010-030 316 

03050109030010 127 

03050109040010 121 

Total primary DA = 760

338 03060101060010-060 275 

03060101070010 21. l c 

03060101070020 41.4 

Total primary DA =338

13,800 03050106010050 29.4 

03050106050010-070 592 

03050106060010-100 601 

03050106070030 80.8 

03050106070 050 1.46 

03050106080010-020 152 

03050106090'010 - 030 261 

03050107050 060 - 070 137 

03050108050 030 108 

03050110010010 0.62C

Total primary DA = 2, 1 1 0

Secondary SWPA

HUC 

HUC basins basin DA 

(km2)

03050108010010-090 677 

03050108020 020 37.8 

03050108030010 47.5

Total secondary DA = 762

N/A

03060101010010-030 250 

03060101020010 129 

Total secondary DA =379

N/A

03050203010010-020 206 

03050203020010-030 240 

03050203030010-020 177 

03050203040010-040 265 

03050203050 010 79.8 

Total secondary DA = 968

N/A

N/A

03050 105b 6,420 

03050106010010-040 283 

03050106020010-040 379 

03050106030010 137 

03050106040 010 - 050 423 

03050106070010-020 163 

03050106070040 87.0 

03050107010010-070 445 

03050107020010 90.6 

03050107030010-030 137 

03050107040010-030 221 

03050107050010-050 423 

03050107060010-110 639 

03050108010010-090 677 

03050108020010-050 338 

03050108030010-020 143 

03050108040010-040 311 

03050108050010-020 251 

03050108050040 67.4 

Total secondary DA = 1 1,640

Primary and Secondary Source-Water Protection Areas 29
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999-Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

Intake 

no.

(fig-1)

Intake DAa 

(km2)

Primary SWPA

14-digit HUC basins

HUC

basin DA

(km2)

Secondary SWPA

HUC basins

HUC

basin DA

(km2)

S40102 - -6,260 03050109140010 ' 

0305010914Q 030-040- 

03050109150010-080; 

03050109160;020' ! . 

03050109160 040 "- 090 

 03050109*170 010-060 

.03050109180 010-to 

03050109190010-090 

03050109200^010 '.'.'.

, 92.6

'l72; - 

738- 

.56:2 

420

615 ;

258 . 

612- 

 51'

Total primary DA = 3,010

03050109010010-020 . - 

03050109020 010 -030 ( [ ', 

03050109030010 ( * ' . 

03050109040 010 - 050 ', \ ' 

0305010905001-0 ; '. 

03050109060010,030 - : ; 

03050109070010 J ; ,* 

03050 109080 010' -090 ; ; - 

03050109090 010- 020 , , ' ' ' 03050109100 oio - oso - ; ! ; " 

030501091,10010 '. . ' . ' ' 

030501091-20 010 -040] ' - - { . * 

0305010913doiO-030. '.' ;- " 

03050109140020| '.' -.'.'. ' ''

03050109160010- ; ; ;;';

-03050109160030 .'..: ; ' ;. '.-. 

- Total -secondary1 DA

196 

316; 

127 

369 ' 

&5.4; 

'.95.7; 

* SO.?.

^ ' 

', ^88.2

* 298!

' 92'.4;

284: , .

330 

'. 108 '

; 40.4 

3,250:

S42-104 ,03050107040010-020 - ; 159 

03050107040 030 ! ; ' ,' 19.5C 

1 Total'primary DA= 179

30 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
Table 4. Identifying information for primary and secondary source-water protection areas for 45 

surface-water intakes in South Carolina, 1999--Continued

[SWPA, source-water protection area; DA, drainage area; km2 , square kilometer; HUC, Hydrologic Unit Code; N/A, not 

applicable; IND, indeterminate, flow tidally affected]

Intake Primary SWPA lntake Intake DAa 

na (km2) 14-digit HUC basins

S46109 7,820 03050101160010-050

03050101170010-040

03050101180010-030

03050101190010-020

03050102030020

03050102040030-040

03050102050010-020

03050102060010-020

03050102070010-030

Total primary DA =

HUC 

basin DA 

(km2)

443

379

463

172

65.1

102

273

178

251

2,330

Secondary SWPA

HUC basins

03050101010010-060

03050101020010-030

03050101030010-070

03050101040010-020

03050101050050

03050101060010-050

03050101070010-040

03050101080010-030

03050101090010-030

03050101100010-030

03050101110010-020

03050101120010-050

03050101130010

03050101140010

03050101150010-040

03050102010010-030

03050102020010-020

03050102030010

03050102030030

03050102040010-020

Total secondary DA

HUC 

basin DA 

(km2)

469

221

419

256

158

307

547

309

270

299

173

259

68.2

204

687

296

250

103

67.6

125

= 5,490

Difference in intake DA and sum of primary and secondary DA's caused by rounding. 

Includes entire 8-digit HUC basin. 

cPartial drainage area of 14-digit HUC basin.

Primary and Secondary Source-Water Protection Areas 31
Supplemental Data

Pilot study estimation of travel time for the intake on Shaw Creek in Aiken, S.C. 

(T.H. Lanier and W.F. Falls, U.S. Geological Survey, written commun., 1998)

32 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
PILOT STUDY ESTIMATION OF TRAVEL TIME FOR THE INTAKE ON SHAW CREEK IN 

AIKEN, S.C.

Steps to estimate the 24-hr travel distance for an intake are as follows:

1. Determine drainage area at the intake and stream distances

2. Determine reach slope (Piedmont sites only)

3. Select an appropriate index gaging station

4. Determine the 24-hr range

5. Delineate drainage areas within the 24-hr range

6. Determine average drainage areas and final velocities

7. Determine the 24-hr travel distance

A 24-hr time-of-travel study was completed for the Aiken, S.C., intake on Shaw Creek, which is approximately 

55 km long. The intake drainage area (IDA) (step 1) for the Aiken intake is 180 km and is located at river kilometer 

(RK) 21.9, approximately 33 km downstream from the basin headwaters. Because the Shaw Creek drainage basin lies 

in the upper Coastal Plain, the determination of the reach slope (step 2) is not required.

There are no current or discontinued USGS gaging stations on Shaw Creek (Cooney and others, 1997). However, 

two active gaging stations are present in nearby basins Station 02172640 on Dean Swamp Creek near Salley, S.C., 

and Station 02196689 on Little Horse Creek near Graniteville, S.C. (fig. S-l). Station 02172640 has 17 years of record 

and a drainage area of 80.8 km2 . Station 02196689 has 9 years of record and a drainage area of 68.9 km2 . Due to a longer 

period of record, station 02172640 was chosen as the index station for Shaw Creek (step 3). The following data for 

Station 02172640 were used to compute the travel-time points and primary travel-time segment for the Aiken sourcewater protection area:

Drainage area (GDA) = 80.8 km2 ,

Mean flow (MGQ) = 0.70 m3/s,

10-percent exceedance flow (GQ10) = 0.91 m3 /s,

50-percent exceedance flow (GQ5 o) = 0.68 m3 /s, and

90-percent exceedance flow (GQ90) = 0.48 m3/s.

Computation of the 24-hour range

In step 4, the minimum 24-hr distance is computed by using the Coastal Plain equation where

Da = IDA/2 = 180/2 = 90 km2 ;

average 90-percent exceedance flow (090) = 0.48 x (90/80.8) = 0.53 m3 /s;

average mean flow (Qa) = 0.70 x (90/80.8) = 0.78 m3/s;

D'a = (9.8°'5 x (90 x 106) L25)/0.78 = 35.2 x 109 (dimensionless); and

Q'a90 = 0.53/0.78 = 0.68 (dimensionless).

The Coastal Plain velocity is determined by using equation 2 from this report for Coastal Plain streams. 

Vp9() = 0.020 + 0.051 (35.2 x 109) °- 821 (0.68)'°-465 (0.53/90 x 106) = 0.18 m/s

Supplemental Data 33
83°

DCD (B

CO(DQ. ai -5en oSi- CD"

TI 

o

>

CDCOIo

CD

S. ST

T>cCT o'COC aCD3b

CD CD CO

< I ~~ 

EXPLANATION

State boundary Physiographic boundary 

Stream

® Surface-water intake 

USGS gaging station

North Cardlikd "l^ir-^r ' ' / "-, V-A-/ _ Lake / V

Base from U.S. Geological Survey 1:2,000,000 scale Digital Line Graphs

Figure S-1. Location of the Aiken surface-water intake in South Carolina.
The 24-hr travel distance90 for the 90-percent exceedance flow is as follows.

Travel distance90 = (0.18 m/s)(24 hrs)(3,600 seconds per hour(s/hr)) (0.001 km/m) = 

15.5 km upstream from the intake or RK 37.4.

The maximum 24-hr distance is computed by using the Coastal Plain equation where

average 10-percent exceedance flow (Qlo) = 0.91 x (180/80.8) = 2.03 m3 /s; 

average mean flow (Qa) = 0.70 x (180/80.8) = 1.56 m3/s; 

D\ = (9.8°- 5 x (180 x 106) L25)/1.56 = 41.8 x 109 (dimensionless); and 

g'fllo = 2.03/1.56 = 1.30 (dimensionless).

The Coastal Plain velocity is determined by using equation 2 from this report for Coastal Plain streams.

Fplo = 0.020 + 0.051 (41.8 x 109)0 ' 821 (1.30)'0-465 (2.03/180 x 106) = 0.29 m/s 

The 24-hr travel distance 10 for the 10-percent exceedance flow is as follows:

Travel distance 10 = (0.29 m/s)(24 hrs)(3,600 s/hr)(0. 001 km/m) = 

25.1 km upstream from the intake or RK 47.0.

This defines a 24-hr range within the Shaw Creek Basin with the minimum and maximum 24-hr distances at RK 

37.4 and RK 47.0, respectively, which are shown in figure S-2.

Supplemental Data 35
Hydrologic unit code 

no. 030502040200010

Minimum 24-hour 

travel distance

15

EXPLANATION

Pond

 Basin boundary 

Subbasin boundary 

Stream

River kilometer 

Surface-water intake

Maximum 24-hour 

travel distance

Hydrologic unit code 

no. 030502040200020

4

N

1

6 KILOMETERS

Hydrologic unit code 

no.030502040200030

Figure S-2. Maximum and minimum 24-hour distances for the Aiken intake on Shaw Creek, South Carolina.

36 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
Delineation of drainage areas within the 24-hour range

Drainage areas of 95.6 km2 and 25.1 km2 were computed at the minimum and maximum 24-hr travel points, 

respectively (step 5). The basin was subdivided at the confluences of Tiger Creek (RK 44.0) and Paces Branch (RK 

39.1) because these tributaries contributed more than 30 percent of the total drainage area at the confluence point. 

The drainage area of Shaw Creek just below and above the Tiger Creek confluence is 40.4 km2 and 24.6 km2 , 

respectively, and the drainage area just below and above the Paces Branch confluence is 78.7 km2 and 57.5 km2 , 

respectively. The basin was further subdivided at RK 42.8 to determine a drainage area of 43.5 km2 , so that no 

segment would have a change of more than 30 percent between the maximum and minimum drainage areas.

Computation of the average drainage area and final velocities for each segment

The drainage areas for Shaw Creek were tabulated from the IDA to the maximum 24-hr TOT point and are 

listed in table S-1 (step 6). The Da and velocities were computed for each segment by using the 10-, 50-, and 90- 

percent exceedance flows. An example of these computations is shown below, and the results are listed in table S-1.

Table S-1. Drainage areas for Shaw Creek, S.C., calculated from the intake drainage area to the maximum 24-hour time-oftravel point

[V lo, V50, and V90, velocity calculated at 10-, 50-, and 90-percent exceedance flows, respectively; TOT )0, TOT50, and TOT90, time of travel for 10-, 50-, 

and 90-percent exceedance flows, respectively; km, kilometer, km2 , square kilometer; m/s, meter per second; hr, hour]

Intake

Location

Minimum 24-hour point

Downstream from Paces

River 

kilometers 

(km)

21.9

37.4

39.1

Drainage 

area 

(km2)

180.0

95.6

78.7

Average 

drainage 

area 

(km2)

137.8

87.2

V, 0 

(m/s)

0.27

0.24

V5o 

(m/s)

0.23

0.21

V90 

(m/s)

0.20

0.18

TOT10 

(hr)

15.9

2.0

TOT50 

(hr)

18.7

2.2

TOT90 

(hr)

21.5

2.6

Branch confluence3

39.1

River kilometer 42.8C

Downstream from Tiger Creek 44.0 

confluenced

Upstream from Tiger Creek 44.0 

confluence6

Maximum 24-hour point 47.0

57.5

43.5

40.4

24.6

19.2

68.1 0.23 0.20 0.17 0.0 0.0 0.0

50.5 0.22 0.19 0.16 4.7 5.4 6.4

42.0 0.21 0.18 0.16 1.6 1.9 2.1

32.5 0.20 0.18 0.15 0.0 0.0 0.0

21.9 0.19 0.16 0.14 4.4 5.2 6.0

aPaces Branch enters into Shaw Creek.

bShaw Creek drainage area upstream from Paces Branch confluence.

°Delineation due to 30-percent rule.

dTiger Creek enters into Shaw Creek.

eShaw Creek drainage area upstream from Tiger Creek confluence.

Supplemental Data 37
The computations for the segment between IDA and the minimum 24-hr travel point at RK 37.4 for the 10-percent 

exceedance flow are as follows:

Da = (95.6+180.0)72 = 137.8 km2 ;

average 10-percent exceedance flow (010) = 0.91 x (137.8/80.8) = 1.55 m3 /s;

average mean flow (Qa) = 0.70 x (137.8/80.8) = 1.19 m3/s;

Ua = (9.8°- 5 x (137.8 x 106) L25)/1.19 = 39.3 x 109 (dimensionless); and

Q'aW = 1.55/1.19 = 1.30 (dimensionless).

The Coastal Plain velocity equation is applied as follows:

Vp{0 = 0.020 + 0.051(39.3 x 109)°- 821 (1.30)-°-465 (1.55/137.8 x io6) = 0.27 m/s.

The time of travel for this segment is:

Time of travel = ((37.4 km - 21.9 km)(l,000 m/km))/((0.27 m/s)(3,600 s/hr)) = 15.9 hr.

This calculation can be repeated for the other subreaches.

Computation of the 24-hour travel distance

From table S-l, the 24-hr travel distance can be computed directly (step 7).

For the 10-percent exceedance flow:

Summed TOT10 = 15.9 + 2.0 + 4.7 + 1.6 = 24.2 hrs;

Remainder1() = summed TOT10 - 24-hr TOT = 24.2 - 24.0 = 0.2 hr or 720 seconds(s); and

Final 24-hr TOT point 10 = (upper RK where 24 hrs was exceeded) - (remainder 10 multiplied by the velocity

of the segment where 24 hrs was exceeded) = 44.0 - [(720 s)(0.21 m/s)(0.001km/m)] = RK 43.8 (21.9 km

upstream from the intake).

For the 50-percent exceedance flow:

Summed TOT50 = 18.7 +2.2 + 5.4 = 26.3 hrs; 

Remainder50 = 26.3 - 24.0 = 2.3 hrs or 8,280 s; and

Final 24-hr TOT point50 = 42.8 - [(8,280 s)(0.19 m/s)(0.001km/m)] = RK 41.2 (19.3 km upstream 

from the intake).

For the 90-percent exceedance flow:

Summed TOT90 = 21.5 + 2.6 = 24.1 hrs; 

Remainder90 = 24.1 - 24.0 = 0.1 hr or 360 s; and

Final 24-hr TOT pomt90 = 39.1 - [(360 s)(0.18 m/s)(0.001km/m)] = RK 39.0 or 17.1 km upstream 

from the intake.

The 24-hr travel points are shown in figure S-3.

38 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999
EXPLANATION

Pond

Basin boundary

Stream

15 River kilometer

0 Surface-water intake

o

TOT50

Final 24-hour time-of-travel 

point for the 10-, 50-, and 

90-percent exceedance flows

6 KILOMETERS

Figure S-3. Final 24-hour time-of-travel points for the 10-, 50-, and 90-percent exceedance flows for the Aiken intake on Shaw 

Creek, South Carolina.

Supplemental Data 39
Paces Branch, a tributary to Shaw Creek, falls within the 24-hr source-water protection area for Shaw Creek 

for the 10- and 50-percent exceedance flows. Computations similar to those completed on Shaw Creek were 

completed on Paces Branch tributary. The velocities were determined by solving equation 2. The IDA for Paces 

Branch is the drainage area at the mouth. The same index gaging station used for Shaw Creek is used for Paces 

Branch. TOT from the mouth of Paces Branch to the intake on Shaw Creek for the 10- and 50-percent exceedance 

flows is 17.9 and 20.9 hrs, respectively (table S-l). Because the 90-percent exceedance flow on Shaw Creek does 

not affect Paces Branch, the minimum range for Paces Branch is computed by using the 50-percent exceedance 

flow. The maximum and minimum distances are computed as follows:

Maximum distance = (24 hr - 17.9 hrs)(3,600 s/hr)(0.19 m/s)(0.001 km/m) = 4.2 km 

Minimum distance = (24 hr - 20.9 hrs)(3,600 s/hr)(0.15 m/s)(0.001 km/m) = 1.7 km

The maximum and minimum velocities of 0.19 and 0.15 m/s, respectively, were computed by using the same 

methodology as described in the section on computation of the 24-hr range. The maximum point of 4.2 km is shown 

in figure S-2.

Drainage areas were computed on Paces Branch at RK 0, 1.3, and 4.2. The drainage area at RK 1.3 was used 

because it had been previously delineated. Table S-2 lists the drainage areas of the delineated subareas, the 

computed velocities at the 10- and 50-percent exceedance flows, and the time of travel for the two flows. The 

24-hr TOT distance can be computed directly by using table S-2.

Table S-2. Drainage areas of delineated subareas of Paces Branch, S.C., computed velocities at the 

10- and 50-percent exceedance flows, and associated travel times

[V] 0 and V50, velocity calculated at 10- and 50-percent exceedance flows, respectively; TOTi 0 and TOT50, time of travel for 

10- and 50-percent exceedance flows, respectively; km, kilometer, km , square kilometer; m/s, meter per second; hr, hour]

 . r. . Average River Drainage , . , T ,, ^^^ ~ 

Location kilometers area « ** ^ V50 TOT TOTso

(km) (km2) "" (m/S) (m/S) (hr) (hr) 

(km )

Mouth of Paces Branch

River kilometer 1.3a

Maximum 24-hour point

0.0

1.3

4.2

21.1

17.9

9.3

19.5

13.6

0.18 0.16 2.0

0.17 0.15 4.7

2.2

5.4

Previously delineated drainage area used for the minimum point.

For the 10-percent exceedance flow:

Summed TOT10 = 2.0 + 4.7 = 6.7 hrs;

Remainder10 = 6.7 - (24 -17.9) = 0.6 hr or 2,160 s; and

Final 24-hr TOT point10 = 4.2 - [(2,160 s)(0.17 m/s)(0.001 km/m)] = 3.8 km upstream from the mouth.

For the 50-percent exceedance flow:

Summed TOT50 = 2.2 + 5.4 = 7.6 hrs;

Remainder50 = 7.6 - (24 - 20.9) = 4.5 hrs or 16,200 s; and

Final 24-hr TOT point50 = 4.2 - [(16,200 s)(0.15 m/s)(0.001 km/m)] = 1.8 km upstream from the mouth.

These 24-hr travel points are shown in figure S-3. 

40 Determination of Primary and Secondary Source-Water Protection Areas for Surface-Water Public-Supply Systems in S.C., 1999

if U.S. GOVERNMENT PRINTING OFFICE: 2000 573-082 / 47029 Region No. 8
i I ICpC CALDWELL Determination of the Primary and Secondary Source-Water Protection Areas for Selected 

Surface-Water Public-Supply Systems in South Carolina, 1999