U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 102–03

June 2004

Streamflow Losses through Karst Features in the Upper Peace River 

Hydrologic Area, Polk County, Florida, May 2002 to May 2003

Printed on recycled paper

Introduction

In October 2001, the U.S. Geological 

Survey (USGS) in cooperation with the 

Southwest Florida Water Management 

District (SWFWMD) began a study to 

evaluate the distribution, timing, and 

volume of surface-water to ground-water 

exchange in the Upper Peace River Hydrologic Area in Polk County, Florida (fig. 

1). Historically, ground-water levels in 

this area were above surface-water levels 

(gaining stream), wells and second-order 

magnitude springs flowed, and tributaries 

drained the surrounding highlands (scarps) 

(Stewart, 1966). Strip-mining of phosphate 

ore (1) altered the landscape, (2) changed 

the natural surface-water drainage patterns, 

and (3) changed the ground-water flow patterns by removing the upper 50 ft (feet) of 

sediments and lowering the potentiometric 

surface of the aquifers. Today, this area 

of the Peace River appears to be a losing 

stream. Streamflow losses are predominately through karst features found in the 

low-water channel and the flood plain.

Karst Features

Locations, surface orientations, and dimensions of prominent karst features were 

measured in mid-May 2002 when reaches 

of the river were dry. Examples of features 

are shown in the photographs. Fricano 

fracture (fig. 2) is a coalescing group of 

vertical pipes; Midway sink (fig. 3) is a 

collapsing sinkhole with small fractures 

near the base; Dover sink (fig. 4) at the 

base of the outcrop is located at the end of 

a 200-ft-long distributary in the flood plain; 

and the crevasses (fig. 5) includes multiple 

Figure 1. Upper Peace River Hydrologic 

Area, Polk County, Florida.

Figure 2. Fricano fracture.

Figure 3. Midway sink.

Figure 4. Dover sink. Figure 5. The crevasses.

Lake Hancock

Peace

River

At Bartow

Near

Bartow

Near Homeland

Homeland 4

Homeland 9

At

Fort

Meade

At Clear

Springs

0 1 2 3

0 1 2 3 Miles

Kilometers

EXPLANATION

Karst area inset–

 Shown in figure 6

Kissengen spring

Mine outfall gaging station

Peace River gaging station

Karst feature

Water-level recorder well

County

and

study area

Polk

27o59' 27o45'

81o50' 81o46'
fractures–the largest is 26 feet long and 

spans the riverbed. The spatial distribution 

of the karst features is shown in figure 1. 

Vertically, these features are present at the 

contact between the Peace River and Arcadia Formations. The largest karst feature 

mapped is the catacombs, which is located 

in the flood plain (fig. 6). This feature is 

composed of numerous interconnected 

horizontal and vertical fractures that show 

evidence of scouring by moving water; 

some of the openings are large enough for a 

person to enter. Numerous smaller features 

also are found in the channel and the flood 

plain. 

Streamflow Losses During Late 

Spring 2002

The Peace River ceased flowing at the 

Bartow gaging station on May 12, 2002. 

Intermittent flow in the river was observed 

between May 19 and June 25 with the 

commencement of summer rain, and steady 

flow resumed again in late June 2002 as the 

frequency of summer storms increased (fig. 

7). During the period of intermittent flow, 

surface water was lost to the ground-water 

system via karst features downstream from 

the Bartow gaging station; the length of the 

river reach containing flow increased over 

time but was dry between karst features 9 

and 10 (fig. 6). Interestingly, downstream 

from feature 10, flow was reversed along a 

low-lying section of the riverbed and exited 

the river at a distributary leading to Dover 

sink (fig. 6). The source of the water was 

Sixmile Creek, a mine outfall.

Streamflow losses through karst features 

were measured at selected sites (table 1 and 

fig. 6). Table 1 shows the instantaneous 

volumes of flow lost to selected features 

along the reach of the Peace River riddled 

with karst. In table 1, values shown in blue 

indicate the farthest downstream feature 

to receive flow from the Peace River on 

that day, and values shown in red indicate 

upstream flow in the riverbed. Quantifying 

total losses between individual measuring sections on the river during a specific 

day was not possible because discharge 

at a given measuring section was not at 

steady state–some values changed by more 

than 200 percent during a day. However, 

records from the gaging station at Bartow 

indicated that streamflow losses during late 

spring 2002 ranged from 2 to 30 cubic ft 

per second (ft3/s); all of the water was lost 

upstream from, or at, site 9 (table 1 and fig. 

6). 

Streamflow Losses During Late 

Spring 2003

A seepage run was conducted on May 13 to 

14, 2003, at the end of the dry season. The 

daily mean discharge at the Bartow station 

(upper end) and the Fort Meade station 

(lower end) fell 2 and 8 ft3/s, respectively 

(fig. 8). The seepage run was designed to 

quantify gains and losses to the river during a steady-state period, representing low 

ground-water levels. To maintain steadystate conditions of surface-water flow, the 

control structures were not adjusted during 

the seepage run. The discharge measurements were made using either a standard 

(type AA) or a pygmy current meter and 

standard USGS streamflow measuring 

techniques. Synoptic measurements of 

streamflow were made at 21 cross sec0 1 Mile

0 0.5 1 Kilometer

1/2

Peace

River

Extent of flow on May 20, 2002

Extent of flow on June 25, 2002

Extent of upstream

flow from 

June 19 to 24, 2002

Wabash (2)

Cypress root

Corbett (3)

Cook's

ripple (4)

Fricano (5) Ledges (6)

Midway (8)

Peace River near Bartow (7)

Catacombs

Harley

Jackson

Elephant graveyard (9)

Crevasses

Paternoster complex

Dover sink (10)

Gator

Log

Peace River at Bartow (1)

Orientation

Karst feature–

 Name and number

Gaging station–

 Name and number

EXPLANATION

27o52' 27o54'

81o49' 81o48'

DISCHARGE,

IN CUBIC FEET PER SECOND

4/1/2002 4/15/2002 4/29/2002 5/13/2002 5/27/2002 6/10/2002 6/24/2002 7/8/2002

River is going dry Dry Intermittent flow in river Steady flow

1,000

100

10

1

0.1

0.01

Figure 6. Extent of the Peace River losing 

flow to selected karst features.

Figure 7. Streamflow hydrograph for the Peace River at Bartow gaging station.

0.2

1.2

0.2

5.5

0.9

2.0

blue

2.5

5.1

2.9

red

Table 1. Instantaneous discharge at selected sites in the Upper Peace River Hydrologic Area

Date 11 12 2 3 4 5 6 7 8 9 10

5/20/02 17-0.7 5.5 7.3 2.5 --- Dry Dry Dry Dry Dry

6/11/02 11.0 11.0 12.6 7.7 --- --- Dry Dry Dry Dry

6/14/02 3.2-1.9 2.5 4.5 1.2 0.8 Dry Dry Dry Dry Dry

6/19/02 2.8-20 7.7 --- --- --- --- --- --- --- ---

6/20/02 19-5.1 8.6 --- --- --- --- Dry Dry Dry

6/24/02 24-34 27.0 --- --- --- --- 12.2 4.7 Dry

6/25/02 27-44 30.0 28.1 22.6 --- --- --- --- 5.6 ---

1

Range of instantaneous discharge from rating. 2Mean daily discharge from rating.

[discharge, in cubic feet per second; site numbers shown in figure 6; ---, site not measured; 

numbers indicate the farthest downstream feature receiving flow on that date; increasing or

decreasing range for site 1 indicates rising or falling discharge, respectively; numbers indicate

flow is upstream and leaves the river via a distributary]

Site Numbers
tions along a 13-mile stretch of the river. 

Thirteen of the sections were on the Peace 

River; surface-water inflows from eight 

mine outfalls and tributaries also were 

measured (fig. 9). The increase or decrease 

in stream flow (differences in instantaneous 

discharge) between measurement sites 

that could not be accounted for through 

tributary influx or out-of-stream diversions was assumed to be the net volume 

of water exchanged between the river and 

the ground-water system (Simonds and Sinclair, 2002, p. 16).

During the May 2003 seepage run (fig. 

10), decreasing streamflow was assumed 

to reflect seepage to the ground-water 

system. The error bars provided a way to 

separate measurement error from changes 

in stream flow. The inherent error in a 

“fair” discharge measurement in a natural river environment is estimated at ±5 

percent (Rantz and others, 1982). Changes 

in discharge greater than the range span by 

the error bars were accepted as net changes. 

Losses were insignificant (less than 2 ft3/s) 

between sites 1 and 2. No losses were 

measured between sites 2 and 4. Streamflow losses equaling 6 ft3

/s were measured 

between sites 4 and 5. Streamflow losses 

equaling 10 ft3/s were measured between 

sites 7 and 11. The Clear Springs station 

(site 11) had the lowest discharge during 

the seepage run. Three mine outfalls and a 

drainage ditch contributed 7 ft3/s of inflow 

to the Peace River between the Clear 

Springs (site 11) and Homeland (site 16) 

stations. Two tributaries contributed 3 ft3/s 

of inflow to the Peace River between sites 

26 and 31. Streamflow losses primarily 

occur along the reach between the Bartow 

and Clear Springs stations, corresponding 

to locations of prominent karst features (fig. 

9 and 10).

Potential for Surface-Water and 

Ground-Water Exchanges

The potential and rate of exchange of water 

between the surface-water and groundwater systems is a function of the difference between the river stage and aquifer 

head. Streamflow losses will occur whenever the river stage exceeds the aquifer 

head, but the rate depends on the magnitude of the difference, the conductivity of 

riverbed deposits, and the saturated area of 

the channel (Simonds and Sinclair, 2002, 

p. 23). The difference between river stage 

and aquifer head along the Peace River is 

not constant throughout the year; it fluctuates between wet and dry seasons, and the 

transient nature of these changes along 

the river is poorly known. Additionally, 

periodic water-level measurements from 

existing wells in the Upper Peace River 

Seepage run conducted

5/1/2003 5/8/2003 5/15/2003 5/22/2003 5/29/2003

DAILY MEAN DISCHARGE,

IN CUBIC FEET PER SECOND

300

250

200

150

100

50

0

Estimated discharge Peace River at Bartow

Peace River at Fort Meade

Figure 8. Streamflow hydrographs for the Peace River at Bartow and at Fort Meade gaging 

stations, May 2003.

Figure 9. Locations of Peace River cross sections measured during the seepage run May 13-14, 2003.

2

3

6

13

19

31

26

16

7

11

4

5

1

At Fort Meade 

Near Homeland

Sixmile Creek

0

0

1

1

2

2

3 Miles

3 Kilometers

Peace

River

[3 ft3/s gain from 

surface-water system]

[7 ft3/s gain from surface-water system]

[10 ft3/s loss to ground-water system]

[6 ft3/s loss to ground-water system]

Barber Branch

CS-8 outfall

Clear Springs

Near Bartow

At Bartow

19

EXPLANATION

Mine outfall gaging station and name

Peace River gaging station and name

Location of prominent karst feature

Measuring section location and

 site number

27o46' 27o52'

81o52' 81o46'
Hydrologic Area indicate that water levels 

in the intermediate aquifer system and the 

Upper Floridan aquifer were 20 ft lower in 

May 2002 than in May 2003.

Preliminary analysis of the differences 

between the stage of the Peace River and 

head in the aquifers in the Upper Peace 

River Hydrologic Area was based on data 

from an existing pair of wells (Homeland 

4 and Homeland 9) located within 1 mile 

of the Peace River near the Homeland 

gaging station (fig. 1). The wells penetrate 

the intermediate aquifer system and the 

Upper Floridan aquifer, respectively, and 

are the only available monitor wells located 

in close proximity to the river. The head 

difference between these two aquifers indicates recharge conditions and is relatively 

constant at about 4 ft (fig. 11). Water-level 

hydrographs show that the stage of the 

Peace River near the Homeland gaging station was higher than the heads in the aquifers, indicating the potential for the river to 

be a losing stream (fig. 11). The difference 

between the river stage and the head in the 

intermediate aquifer system is smaller during the wet season and larger during the dry 

season, ranging from about 5 to 12 ft 

(fig. 11). The El Niño-Southern Oscillation condition resulted in above-normal 

rainfall that was reflected on hydrographs 

as steeply rising water levels in December 

2002 (fig. 11). The dramatic drop in water 

levels on January 24 to 25, 2003, resulted 

from large ground-water withdrawals 

associated with frost and freeze protection 

of crops (fig. 11). 

Summary

This fact sheet summarizes the preliminary 

results determined during the first year of 

the study and is part of a comprehensive 

investigation to quantify the streamflow 

losses in the Upper Peace River Hydrologic 

Area. Measured streamflow losses did not 

exceed 30 ft3/s during the dry seasons of 

late spring 2002 and 2003. In May 2002, 

streamflow losses ranged from about 2 to 

30 ft3/s. In May 2003, the aquifer head 

was 20 ft higher than in May 2002, and 

streamflow losses did not exceed 16 ft3/s. 

A factor impeding the quantification of the 

distribution, timing, and volume of surfacewater to ground-water exchange is the lack 

of aquifer head data near the Peace River. 

Several well clusters are to be drilled, 

sampled, and monitored on the Peace 

River flood plain where karst features are 

prominent. The hydrologic data collected 

from these sites will provide a better 

understanding of the transient nature of the 

water exchange between the river and the 

ground-water system.

Selected References

Lewelling, B.R., Tihansky, A.B., and 

Kindinger, J.L., 1998, Assessment of the 

hydraulic connection between ground 

water and the Peace River, west-central Florida: U.S. Geological Survey 

Water-Resources Investigations Report 

97–4211, 96 p.

Rantz, S.E., and others, 1982, Measurement 

and computation of streamflow; vol. 1. 

Measurement of stage and discharge: 

U.S. Geological Survey Water-Supply 

Paper 2175, 284 p.

Simonds, F.W., and Sinclair, K.A., 2002, 

Surface water-ground water interactions along the Lower Dungeness River 

and vertical hydraulic conductivity of 

streambed sediments, Clallam County, 

Washington, September 1999-July 2001: 

U.S. Geological Survey Water-Resources 

Investigations Report 02–4161, 60 p.

Stewart, H.G., Jr., 1966, Ground-water 

resources of Polk County: Florida Geological Survey Report of Investigation 

44, 170 p.

DISCHARGE,

IN CUBIC FEET PER SECOND

26 (At Bartow)

25

24

25

19

20

18

9

13

17

14

15

15

(At Fort Meade) 18

5

0 2 4 6 8 10 12 14

10

15

20

25

30

Seepage Run, May 13 to 14, 2003

Discharge values in green measured on May 13 

Discharge values in blue measured on May 14

1

2 3 4

5 6

7

11

13

16

16 19 26

31

Site numbers and 5 percent error bars shown in red

DISTANCE BELOW PEACE RIVER AT BARTOW GAGING STATION, IN MILES

WATER LEVEL OR STAGE,

IN FEET ABOVE NATIONAL GEODETIC VERTICAL DATUM OF 1929

90

85

80

75

70

65

11/1/2002 1/1/2003 3/1/2003 5/1/2003

Peace River near Homeland gaging station

Homeland 4 well

(Intermediate aquifer system)

Depth is 202 ft; casing is 56 ft

Homeland 9 well

(Upper Floridan aquifer)

Depth is 746 ft; casing depth 

is unknown

Rise due to

excess rainfall

Decline due to large

ground-water withdrawals

Figure 11. Surface-water stage and ground-water level hydrographs for Peace River near 

Homeland gaging station and Homeland 4 and 9 wells (November 2002 through May 2003).

Figure 10. Peace River site numbers, discharge, and error bars for data collected during the 

seepage run conducted May 13 to 14, 2003.

For further information, contact:

Lari A. Knochenmus 

U.S. Geological Survey

The University Center for Business 

10500 University Center Drive, Suite 215

Tampa, Florida 33612-6427 

Telephone: 813-975-8620 x160 

Fax: 813-975-0839

Email: lari@usgs.gov 

For additional copies of this report, please 

write to:

U.S. Geological Survey

Branch of Information Services

Box 25286

Denver, CO 80225