St.AndrewBayResourceManagementAssociationwww.sabrma.org

Fall 2012

An Introduction to St. Andrew Bay, Florida Linda Fitzhugh

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The St. Andrew Bay system is located in Panama City, Florida. The bay covers

approximately 277 km2 and has a watershed of 2,975 km2 which lies almost entirely within Bay

County (Brim and Handley, 2007). The St. Andrew Bay system contains four coastal plain

estuaries: West Bay, North Bay, St. Andrew Bay, and East Bay (Figure 1). The mean depth in

West Bay, North Bay, and East Bay is approximately 2.1 meters while St. Andrew Bay has a

mean depth of 5.2 meters and a maximum depth of 19.7 meters (Ichiye and Jones, 1961).

West Bay lies northwest of an imaginary line separating West Bay from North Bay.

West Bay covers an area of 7,113 ha (Brim and Handley, 2007) and as of 1992, it supported 790

ha of seagrass which represents only half of the seagrass coverage reported for 1953 (Figure 2).

Because the water clarity in different parts of West Bay varies, this bay was subdivided into

West Bay Bowl (WBBOWL), the area south of an imaginary line that extends east from the

Intracoastal Waterway and West Bay Arm (WBARM), the area north and east of this line. Burnt

Mill Creek and Crooked Creek drain into West Bay Arm, and the Gulf Intracoastal Waterway,

built around 1950, connects West Bay to Choctawhatchee Bay in Destin, Florida. Treated

effluent from the Panama City Beach Wastewater Treatment Plant was discharged into West Bay

Bowl from 1970 to 2011. As of April 2011, this treated effluent has been dumped at a nearby

upland wetlands site west of Highway 79. Future development in the West Bay watershed is

assured as the present silviculture lands are transformed into industrial, residential, and

commercial areas with the new Northwest Florida Beaches International Airport as the focal

point. Approximately half of the 30,350 ha of uplands surrounding West Bay will be developed

over the next several decades.

North Bay occupies the area between Deer Point Dam and the Hathaway Bridge. It

covers 2,702 ha and supports 755 ha of seagrass (Brim and Handley, 2007). Seagrass coverage

has not changed significantly since 1953 although water flow changed drastically in 1961 when

the dam was built. Eventually the estuarine system trapped behind the dam became Deer Point

Lake which now serves as the source of drinking water for Bay County. It is estimated that 60%

of the freshwater entering the St. Andrew Bay system flows over Deer Point Dam (Rodriquez

and Wu, 1990).

St. Andrew Bay lies south of the Hathaway Bridge and extends east toward the Dupont

Bridge. At its southern end, St. Andrew Bay is connected to the Gulf of Mexico at two inlets –

West Pass, the main shipping channel, built in 1938, connecting the Gulf of Mexico to the Port

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of Panama City, and East Pass, the original opening to the Gulf of Mexico which is no longer

navigable (personal observations). St. Andrew Bay covers an area of 10,607 ha and contains

1,045 ha of seagrass (Brim and Handley, 2007). From 1953 to 2003, seagrass coverage in St.

Andrew Bay has remained relatively constant (Figure 2).

East Bay lies east of the Dupont Bridge. It covers 7,551 ha and supports 1,020 ha of

seagrasses (Brim and Handley, 2007). Sandy Creek and Wetappo Creek empty into East Bay,

and the Gulf Intracoastal Waterway connects East Bay to the Apalachicola River in

Apalachicola, Florida. Seagrass coverage in East Bay has also remained relatively constant over

the past five decades (Figure 2).

From 1992 to 2003, seagrass cover increased in the four main bays of the St. Andrew Bay

system (Figure 2; Table 1; Appendix A); however, the increase in seagrass cover in West Bay

occurred mainly in West Bay Arm in the seagrass beds adjacent to Burnt Mill and Crooked

Creeks (St. Andrew Bay RMA seagrass monitoring data, unpublished). Furthermore, at one

seagrass monitoring site in West Bay Bowl that is adjacent to the Intracoastal Waterway,

seagrass cover decreased since 2000, the year seagrass monitoring started in the St. Andrew Bay

system (St. Andrew Bay RMA seagrass monitoring data, unpublished).

Water flow in St. Andrew Bay

The mean tidal range for St. Andrew Bay is relatively small, only 0.4 meters. However,

it more than doubles during the summer when the winds are out of the south and during the

winter, when generally northerly winds blow, water is pushed out of the bay creating some of the

lowest tides of the year (Tolbert and Austin, 1959; Salsman and Howard, 1989). Salsman and

Howard (1989) reported that the phases of the moon do not significantly alter the tidal range in

St. Andrew Bay; therefore, extreme high and low tides are due mainly to changes in the winds

and in barometric pressure.

Although the tidal range is small, saltwater does enter the bay through West Pass and to a

lesser extent East Pass. The inflow of saltwater from the Gulf of Mexico creates a vertical

salinity gradient that changes as the halocline moves up or down within the water column, and

much of this movement is controlled by the amount of rain the area receives (Ichiye and Jones,

1961). Bottom water salinities that are up to two times greater than surface water salinities have

been recorded in the bay, especially within the far reaches of West Bay, North Bay, and East Bay

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(Hydroqual, Inc. and Vittor & Associates, Inc., 1993). Although surface heating of the bay does

occur, the temperatures of the surface and bottom waters do not differ significantly throughout

the year; therefore, the stability in the bay is due to the vertical salinity gradients that exist

(Ichiye and Jones, 1961).

In general, the mean currents in St. Andrew Bay show a classic two-layer estuarine

circulation pattern with surface currents flowing toward the Gulf of Mexico and bottom currents

flowing into the bay through West Pass (Hydroqual, Inc. and Vittor & Associates, Inc., 1993).

However, near the Intracoastal Waterway (ICW) in West Bay and East Bay, both surface and

bottom currents flow toward the ICW (Figure 3). Therefore, the overall flow balance results in

mean inflow rates from the Gulf of Mexico and Deer Point Dam of 278 and 27 m3/s,

respectively, which is offset by mean outflow rates from West Bay and East Bay into the ICW of

258 and 58 m3/s, respectively (Hydroqual, Inc. and Vittor & Associates, Inc., 1993). It is

important to note that the mean currents may change in volume and/or direction depending on

changes in the amount of rain, wind speed or direction, and volume of inflow from the Gulf.

Because the St. Andrew Bay system is not fed by a major river, its salinity is higher than

that for other estuaries in the Gulf of Mexico (Lott and Loftin, 1982). The bay does receive, on

average, 960 million gallons of freshwater each day from its watershed; approximately 60% of

this freshwater flows over Deer Point Dam, 7% enters West Bay, 22% enters East Bay, while the

rest (11%) flows into the system via stormwater runoff or groundwater discharge (Rodriquez and

Wu, 1990). These surface flows can establish horizontal salinity gradients in the bay which are

further influenced by tidal currents and winds (Ichiye and Jones, 1961; Salsman and Ciesluk,

1978).

There are other sources of freshwater which affect the salinity and mean flow within the

bay. The system receives treated wastewater from several wastewater treatment plants and West

Bay receives hot water from the Smith-Lansing Electric Generating Plant. The Panama City

Beach Wastewater Treatment Plant (WWTP) used to discharge up to 0.44 m3/s of treated

wastewater into West Bay, but this is now being dumped into upland wetlands nearby. The St.

Andrews WWTP discharges up to 0.22 m3/s into St. Andrew Bay, the Tyndall Advanced WWTP

discharges up to 1.32 m3/s through the Bay County diffuser into St. Andrew Bay, and another

0.22 m3/s are discharged directly across from the Bay County diffuser by the Lynn Haven and

Millville WWTP (Rodriquez and Wu, 1990; Figure 4). The facility at Tyndall discharges much

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more effluent than the others since it receives domestic wastewater from all the nearby

incorporated areas as well as wastewater from Stone Container and Arizona Chemical that has

already undergone primary treatment.

Waters introduced into St. Andrew Bay which is directly connected to the Gulf of

Mexico by West Pass and East Pass are flushed relatively quickly. In North Bay, where 2.54

m3/s of freshwater flow over the dam each day, flushing is good as surface waters flow into West

Bay and out through the Intracoastal Waterway or into St. Andrew Bay and out into the gulf

through West Pass. However, both West Bay and East Bay are considered to be poorly flushed

because the net flow of water is toward the ICW which means the water resides in these far

reaches of the bay longer (Rodriquez and Wu, 1990; Hydroqual, Inc. and Vittor & Associates,

Inc., 1993).

Based on the morphological characteristics of the St. Andrew Bay system, the flushing

rate for the entire St. Andrew Bay system is 25 days (Solis and Powell, 1999). A recent study

showed that flushing rates for West Bay and North Bay ranged from eight to 12 days (Eller et. al,

2012). However, the time it takes for an area to flush can be affected by tidal range, winds, and

rainfall. In Watson Bayou, located at the eastern edge of St. Andrew Bay, flushing time

increased significantly from 9 days to 65 days when tidal range was low, and it decreased to 5

days when tidal range was twice the mean range for the bay (Salsman and Howard, 1989).

Moreover, during July, one of the wettest months of the year (Kennedy, 1982), flushing time

decreased while in October, one of the driest months, this increased (Gunter and Barnett, 1986;

Salsman and Howard, 1989).

It is hard to determine flushing time of a specific area since this can be altered drastically

by the tides and by stormwater runoff. However, both West Bay and East Bay are considered to

be poorly flushed. Despite this, the Panama City Beach Wastewater Treatment Plant received

permission in the early 1990s to increase its effluent discharge to 10 million gallons per day, the

rationale being that nutrients must not be problematic since chlorophyll a levels were relatively

low (Baskerville-Donovan et. al, 1997). However, water quality results for 1990-2006 show that

chlorophyll a and turbidity measurements are higher in West Bay than they are in East Bay,

North Bay, or St. Andrew Bay; only Grand Lagoon, a very shallow lagoon with extensive

development along its shores, has chlorophyll a and turbidity values higher than West Bay

(Notestein, 2007).

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Since the population of Panama City Beach is expected to increase over the next several

decades as the uplands around West Bay are developed, the amount of effluent to be discharged

into West Bay Bowl is also expected to increase. After careful study, Hartman and Associates,

Inc. (2001) recommended that the effluent should be removed from West Bay Bowl and instead

discharged into an upland area nearby. This was accomplished in April 2011. Hopefully the

removal of this effluent will drastically reduce the amount of dissolved nutrients entering West

Bay Bowl so that chlorophyll a and turbidity levels in this part of the St. Andrew Bay system

will eventually drop.

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Figure 1: Map of the St. Andrew Bay system. West Bay has been divided into two segments: WBBOWL which lies south of an imaginary line extending east from the Intracoastal Waterway (ICW) and WBARM which lies west of an imaginary line separating West Bay from North Bay. Deerpoint Dam separates North Bay from Deerpoint Lake, the freshwater reservoir which provides water to the residents of Bay County, Florida. St. Andrew Bay (SAB) lies between the two bridges and is connected to the Gulf of Mexico at West Pass and East Pass.

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Figure 2: Seagrass coverage (in hectares) in the St. Andrew Bay system based on aerial surveys conducted by the United States Geological Service in 1953, 1964, 1980, 1992 and 2003 (Brim and Handley, 2007). Although seagrass coverage in most of the bay has remained relatively constant over the decades, by 1992, approximately half of the seagrasses in West Bay were lost.

0

400

800

1200

1600

2000

St. Andrew Bay West Bay North Bay East Bay

Seagrass Coverage

 (hectares)

1953

1964

1980

1992

2003

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Figure 3: Map of the St. Andrew Bay system showing the total flux of water (m3/s) in the bay. Figure taken from the report Environmental studies in St. Andrew Bay, Florida by Hydroqual, Inc. and Vittor & Associates, Inc., 1993.

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Figure 4: Point source discharges into the St. Andrew Bay system, 1993. The location of the Lynn Haven discharge, today, is directly across from the Bay County diffuser along with discharge from the Millville WWTP. Figure taken from the report Environmental studies in St. Andrew Bay, Florida by Hydroqual, Inc. and Vittor & Associates, Inc., 1993.

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Table 1: Seagrass cover (hectares) with percent change in seagrass cover for each bay of the St. Andrew Bay system, Panama City, Florida. Cover values were taken from aerial surveys performed by the USGS 1953-2003. Percent change in cover calculations were made by dividing the number of hectares of seagrass lost or gained by the total number of hectares recorded for each bay during the previous monitoring event.

Location 1953 1964 1980 1992 2003 St. Andrew Bay 1034 1147 (11) 1108 (-3) 1045 (-6) 1239 (19)

West Bay 1540 1267 (-18) 1043 (-18) 790 (-24) 1027 (30) North Bay 810 776 (-4) 721 (-7) 755 (5) 800 (6) East Bay 1041 1147 (10) 913 (-20) 1020 (12) 1103 (8)

Total 4425 4337 (-2) 3785 (-13) 3610 (-5) 4168 (15)

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REFERENCES Baskerville-Donovan, Inc., Hydroqual, Inc., and Vittor & Associaties, 1997. Draft copy, City of Panama City Beach Wastewater Treatment Facility Water Quality Based Effluent Limit Level II Study on West Bay. Panama City, FL, Bay County Utilities Department, 160 pp. Blumberg, A. F. and B. N. Kim, 2000. Flow balances in St. Andrew Bay revealed through hydrodynamic simulations. Estuaries 23(1): 21-33. Brim, M. S. and L. R. Handley, 2007. St. Andrew Bay. In: Handley, L., D. Altsman, and R. DeMay, (Eds.), Seagrass Status and Trends in the Northern Gulf of Mexico: 1940- 2002: U.S. Geological Survey Scientific Investigations Report 2006-5287 and U.S. Environmental Protection Agency 855-R-003, pp. 155-169. Collard, S. B., 1992. Characterization of seagrass meadows in St. Andrew (Crooked Island) Sound, Northern Gulf of Mexico: preliminary findings. Final report for the summer research program, Air Force Office of Scientific Research, Bolling Air Force Base, Washington, D.C., 19 pp. Eller, K. T., W. C. Burnett, L. M. Fitzhugh, and J. P. Chanton 2012. Radium Sampling Methods and Residence Times in St. Andrew Bay, FL. To be published. Gunter, J. S. and E. L. Barnett, 1986. Comprehensive shellfish harvesting area survey for West Bay, Bay County, Florida. Tallahassee, FL, Florida Department of Natural Resources, Shellfish Environmental Assessment Section, 137 pp. Hartman & Associates, Inc., 2001. City of Panama City Beach Wastewater Reuse Feasibility Study. Panama City, FL, Bay County Utilities Department, 20 pp. Hydroqual, Inc., 1991. St. Andrew Bay Phase 1 Hydrodynamic and Water Quality Modeling. Report to the Bay County Board of County Commissioners, 56 pp. Hydroqual, Inc. and B. A. Vittor & Associaties, Inc., 1993. Environmental studies in St. Andrew Bay. Report to the Bay County Board of County Commissioners, 4 volumes, 242 pp. Ichiye, T. and M. L. Jones, 1961. On the hydrography of the St. Andrew Bay system, Florida. Limnology and Oceanography 6: 302-311. Kennedy, L.R., 1982. Rainfall summary for the Northwest Florida Water Management District. Havana, Florida. Water Resources Special Report 82-3, 60 pp. Kennesaw, G. A., 1993. Law Environmental, Inc. Final Report: A thermal plume characterization and environmental assessment for Warren Bayou and West Bay. St. Andrew Bay Lansing Smith Electric Generating Plant, 46 pp.

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Keppner, E. J., 1996. An inventory of the biological resources reported from the St. Andrew Bay estuarine system, Bay County, Florida. Bay Environmental Study Team Publication 0001, 72 pp. Lott, D. F. and H. G. Loftin, 1982. Water quality conditions in St. Andrew Bay near the Naval Coastal Systems Center, Panama City, Florida. Naval Coastal System Center, Technical Memorandum NCSC TM 359-82. Musgrove, R. H., J. B. Foster, and L.G. Toler, 1965. Water resources of the Econfina Creek basin area in northwestern Florida. United States Geological Survey, Tallahassee, Florida. Report of Investigations No. 41, 33 pp. Notestein, S. K., 2007. St. Andrew Bay Water Chemistry Summary Report: Florida Lakewatch

Data 1990-2006. Florida Lakewatch, University of Florida, Gainesville, Florida, 48 pp. Rodriquez, J. A. and T. Wu, 1990. Initial analysis of circulation and flushing characteristics of the St. Andrew Bay system. Northwest Florida Water Management District, Water Resources Special Report No. 90-1, 105 pp. Saloman, C. H., S. P. Naughton, and J. L. Taylor,1982. Benthic faunal assemblages of shallow water sand and seagrass habitats, St. Andrew Bay, Florida. U. S. Fish and Wildlife Service, 36 pp. Salsman, G. G. and A. J. Ciesluk, 1978. Environmental conditions in coastal waters near Panama City, Florida. Naval Coastal System Center, Technical Report NCSC TR 337- 78, 96 pp. Salsman, G. G. and W. W. Howard, 1989. Hydrographic survey report, Watson Bayou Marina in Bay County, Florida. Department of Environmental Resources Reference No. 0315- 66061, 24 pp. Solis, R. and G. Powell, 1999. Residence times in Gulf of Mexico estuaries In: Biachi, T. S., J. R. Pennock, and R. R. Twilley (Eds.), Biogeochemistry of Gulf of Mexico Estuaries, John Wiley and Sons, Inc., pp. 29-63. State of Florida Environmental Quality Laboratory, 1983. Hydrographic studies of St. Andrew Bay, Florida: a training exercise March 21-25, 1983. Northeast Technical Service Unit- FDA. Region IV-FDA, 47 pp. Tolbert, W. and G. B. Austin, 1959. On the nearshore marine environment of the Gulf of Mexico at Panama City, Florida. U.S. Navy Mine Defense Laboratory, Technical Paper, 118 pp.

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APPENDIX A

Figure A.1. Seagrass cover in the St. Andrew Bay system in 1953. Photo courtesy of the Florida Fish and Wildlife Conservation Commission, St. Petersburg, Florida.

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Figure A.2. Seagrass cover in the St. Andrew Bay system in 1964. Photo courtesy of the Florida Fish and Wildlife Conservation Commission, St. Petersburg, Florida.

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Figure A.3. Seagrass cover in the St. Andrew Bay system in 1980. The arrow points to the extensive loss of seagrass in the far reaches of West Bay. Photo courtesy of the Florida Fish and Wildlife Conservation Commission, St. Petersburg, Florida.

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Figure A.4. Seagrass cover in the St. Andrew Bay system in 1980. Photo courtesy of the Florida Fish and Wildlife Conservation Commission, St. Petersburg, Florida.

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Figure A.5. Seagrass cover in the St. Andrew Bay system in 2003. Photo courtesy of the Florida Fish and Wildlife Conservation Commission, St. Petersburg, Florida.