Effects of Groundwater on Effects of Groundwater on Salinity in Biscayne Bay Salinity in Biscayne Bay Sarah Bellmund1, Greg Graves2, Steve Krupa2, Herve Sarah Bellmund1, Greg Graves2, Steve Krupa2, Herve Jobert3, Greg Garis1, and Steve Blair4 Jobert3, Greg Garis1, and Steve Blair4 1Biscayne National Park Salinity Monitoring Program, Biscayne National Park, 9700 SW 328th St, Homestead, FL., 33033. USA. 2South Florida Water Management District, 3301 Gun Club Rd. West Palm Beach, FL 33406. USA 3Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, 4800 Rickenbacker Causeway, Miami, FL 33149. USA 4Miami-Dade County Department of Resources Management, 701 NW 1st Ct., Miami, FL 33136. USA
Transcript
Effects of Groundwater on Effects of Groundwater on Salinity in Biscayne BaySalinity in Biscayne Bay
Sarah Bellmund1, Greg Graves2, Steve Krupa2, Herve Sarah Bellmund1, Greg Graves2, Steve Krupa2, Herve Jobert3, Greg Garis1, and Steve Blair4Jobert3, Greg Garis1, and Steve Blair4
1Biscayne National Park Salinity Monitoring Program, Biscayne National Park, 9700 SW 328th St, Homestead, FL., 33033. USA. 2South Florida Water Management District, 3301 Gun Club Rd. WestPalm Beach, FL 33406. USA3Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, 4800 Rickenbacker Causeway, Miami, FL 33149. USA4Miami-Dade County Department of Resources Management, 701 NW 1st Ct., Miami, FL 33136. USA
Historic Aerial Photography of a Spring and Seepage 1938
"Springs of good water are common and wells are to be had by a comparatively small amount of digging. Many springs burst up through the bottom of the bay, and we see fresh water boiling up through the salt." J. Buck, 1877 (Buck, reprinted 1979)
Changes in Biscayne Bay
Central Bay:Central Bay: From River, creek overland sheet flow From River, creek overland sheet flow and ground water springs to an area dominated by and ground water springs to an area dominated by seasonal pulses of discharge from canals with seasonal pulses of discharge from canals with permanently maintained openings to the ocean.permanently maintained openings to the ocean.
South Bay:South Bay: From short coastal stream, surface From short coastal stream, surface sheet flow and groundwater flows to pulsed canal sheet flow and groundwater flows to pulsed canal dischargedischarge
Extreme South Bay:Extreme South Bay: Loss of overland flow due to Loss of overland flow due to construction of the railroad and then US Highway 1construction of the railroad and then US Highway 1
Coastal Ridge and Transverse Glades Courtesy Dr. John Meeder and Peter Harlem
and the South Florida Natural Resources Center
1900-2000: Miami-Dade population increased over 3 orders of magnitude.
No.
Hum
ans (
mill
ions
)0.00.51.01.52.02.53.0
1875 1925 1975 2025Year
?
Changes Affecting the Ecosystems of Biscayne Bay
Biscayne BayContinuous SalinityMonitoring Network
with seagrass coverageBlack Point
C-103Convoy Point
High Salinity Areas 2004-2005
Average Days Greater than 40 psu
• 5.5-10 days • 10.1-15 days• 15.1-20 days• 20.1-25 days• 25.1-30 days• 30.1-35 days• 35.1-40 days
Lighter colors are longer and higher hypersaline conditions
Fender Point Mangroves Site 40: Dry Season Salinity in 2 ppt bins
0500
10001500200025003000350040004500
0 4 8 12 16 20 24 28 32 36 40 44 48Salinity (ppt)
# of
read
ings
Site40DS04Site40DS05
Fender Point Mangroves Site 40: Wet Season Salinity in 2 ppt bins
0
500
1000
1500
2000
2500
0 4 8 12 16 20 24 28 32 36 40 44 48Salinity (ppt)
# of
read
ings
Site40WS04Site40WS05Site40WS06
Convoy Point Mangroves Site 14: Dry Season Salinity in 2 ppt bins
0
500
1000
1500
2000
2500
3000
0 4 8 12 16 20 24 28 32 36 40 44 48Salinity (ppt)
# of
read
ings
Site14DS04Site14DS05
Convoy Point Mangroves Site 14: Wet Season Salinity in 2 ppt bins
0
500
1000
1500
2000
2500
0 4 8 12 16 20 24 28 32 36 40 44 48Salinity (ppt)
# of
read
ings
Site14WS04Site14WS05Site14WS06
Grouped Salinity Convoy Point and Fender Point
Salinity Early Wet Season Compared to Peak Wet Season andOctober Drawdown
June 2007June 2004 June 2005
October 2004 October 2006October 2005
June 2006 June 2007
October 2007
0
500
1000
1500
2000
2500
3000
3500
5/1/2004
7/1/2004
9/1/2004
11/1/2004
1/1/2005
3/1/2005
5/1/2005
7/1/2005
9/1/2005
11/1/2005
1/1/2006
3/1/2006
5/1/2006
7/1/2006
9/1/2006
11/1/2006
1/1 /2007
3/1/2007
5/1/2007
7/1/2007
Date
Discharge
S-20FS-20GS-21AS21
How the managed coastal southern
Biscayne Bay system operates
0
2
4
6
8
10
12
14
16
Jul-0
4
Sep-
04
Nov-
04
Jan-
05
Mar
-05
May
-05
Jul-0
5
Sep-
05
Nov-
05
Jan-
06
Mar
-06
May
-06
Jul-0
6
Sep-
06
Nov-
06
Jan-
07
Mar
-07
May
-07
Jul-0
7
Date
Rain (in
ches
S20F_rainS20G_rainS21A_rain
Biscayne Bay Mangrove Salinity
0
5
10
15
20
25
30
35
40
45
May-2004
Jul-2004
Sep-2004
Nov-2004
Jan-2005
Mar-2005
May-2005
Jul-2005
Sep-2005
Nov-2005
Jan-2006
Mar-2006
May-2006
Jul-2006
Sep-2006
Nov-2006
Jan-2007
Mar-2007
May-2007
Jul-2007
Date
Salin
ity (p
su
Site 14
Site 22
Site 28
Site 40
0
500
1000
1500
2000
2500
3000
3500
5/1/2004
7/1/2004
9/1/2004
11/1/2004
1/1/2005
3/1/2005
5/1/2005
7/1/2005
9/1/2005
11/1/2005
1/1/2006
3/1/2006
5/1/2006
7/1/2006
9/1/2006
11/1/2006
1/1 /2007
3/1/2007
5/1/2007
7/1/2007
Date
Discharge
S-20FS-20GS-21AS21
rainfall
discharge
salinity
Biscayne BayContinuous SalinityMonitoring Network
with seagrass coverageBlack Point
C-103Convoy Point
Site 34/35
Phenomenon of “fresher on bottom”
Aug 2006
Difference 35 – 34 (top – bottom)Salinity
Daily Canal Discharge Volume
Zoomed in Aug 1 thru Sept 5, 2006
Avg bottom = 30.3
Avg top = 31.3
Biscayne BayContinuous SalinityMonitoring Network
with seagrass coverageBlack Point
C-103Convoy Point
Site 18/19
Aug 2006
Phenomenon of “fresher on bottom” occurs elsewhere in Bay
10
Biscayne BayContinuous SalinityMonitoring Network
with seagrass coverageBlack Point
C-103Convoy Point
Site 54/55
Phenomenon of “fresher on bottom” occurs elsewhere in Bay
Aug 2006
Fresh groundwater moving up through the bottom of Biscayne Bay
Karst Cave in Watershed of the Deering Estate
Multiple investigators have measured similar flux rates for groundwater flow including:
Mowry Canal Combined Onshore and Offshore Ground Water Levels
Aug 200519th Full
Sept 20054th New19th Full
Oct 20052nd New20th Full
Nov 20051st New17th Full
Dec 20051st New
Rita9/21/05
Katrina8/26/05
Wilma10/24/05
Rainfall (inches/15 m
in)
0.0
0.5
1.0
1.5
Spec
ific
Con
duct
ivity
(µS/
cm)
52500
53000
53500
54000
54500
55000S-20F RainfallW10 GW-1W10 GW-2
08/01/05
09/01/05
10/01/05
11/01/05
12/01/05
01/01/06
0.0
0.5
1.0
1.5
0
10000
20000
30000S-20F RainfallW9 GW-1W9 GW-2
Mowry Canal Onshore and Offshore Groundwater Well Specific Conductivity
08/01/05
09/01/05
10/01/05
11/01/05
12/01/05
Salin
ity (p
pt)
0
10
20
30
Inside KS A Inside KS B Outside KS A Outside KS B Platform Surface Platform Bottom
Mowry Canal Offshore Salinity
08/01/05
09/01/05
10/01/05
11/01/05
12/01/05
01/01/06
Wat
er L
evel
in fe
et (1
929
NG
VD)
-3-2-1012345
Flux
(cm
/day
)
-2
-1
0
1
2
W 10 GW -1 Flux A (cm/day) Flux B (cm/day)
Win
d D
irect
ion
°
0
100
200
300
400
Mowry CanalSeepage Meter Fluxes. Offshore Groundwater Levels
And Wind Direction
01/01/06
02/01/06
03/01/06
04/01/06
05/01/06
Wat
er L
evel
in fe
et (1
929
NG
VD)
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
W7 GW-1W7 GW-2 W8 GW-1 W8 GW-2
Burger King Combined Onshore and Offshore Ground Water Levels
Spec
ific
Con
duct
ivity
(µS/
cm)
42000
45000
48000
51000
W8 GW-1W8 GW-2
01/01/06
02/01/06
03/01/06
04/01/06
0
3000
6000
9000
12000W7 GW-1W7 GW-2
Burger King Onshore and Offshore Groundwater Well Specific Conductivity
Biscayne Bay Mangrove Salinity
0
5
10
15
20
25
30
35
40
45
50
May-2004
Jul-2004
Sep-2004
Nov-2004
Jan-2005
Mar-2005
May-2005
Jul-2005
Sep-2005
Nov-2005
Jan-2006
Mar-2006
May-2006
Jul-2006
Sep-2006
Nov-2006
Jan-2007
Mar-2007
May-2007
Jul-2007
Date
Salin
ity (p
su
Site 14Site 22Site 28Site 40Site 50Site 56Site 62
Biscayne Bay Mangrove Salinity
1/9/2006
1/16/2006
1/23/2006
1/30/2006
2/6/2006
Salin
ity (p
pt)
10
12
14
16
18
20
22
24
26
28
Inside KS A Outside KS A Inside KS B Outside KS BPlatform Surface
Burger King Offshore Salinity
08/01/05
09/01/05
10/01/05
11/01/05
12/01/05
Salin
ity (p
pt)
0
10
20
30
Inside KS A Inside KS B Outside KS A Outside KS B Platform Surface Platform Bottom
Mowry Canal Offshore Salinity
Relationship Between Flow and Salinity from 2004-2006 at Selected Sites
Mean1
LogT
otFl
ow
403020100
4
3
2
1
0
-1
-2
S 0.481010R-Sq 34.9%R-Sq(adj) 34.8%
BISC14LogTotFlow = 3.190 - 0.04236 Mean1
90 m from shore
2004-2006
BISC42
LogT
otFl
ow
403020100
4
3
2
1
0
-1
-2
S 0.466220R-Sq 36.4%R-Sq(adj) 36.3%
BISC42LogTotFlow = 3.264 - 0.04729 BISC42
317 m from shore
bisc34
LogT
otFl
ow
4035302520
4
3
2
1
0
-1
-2
S 0.486433R-Sq 21.4%R-Sq(adj) 21.3%
BISC34LogTotFlow = 4.359 - 0.06648 bisc34
2961 m from shore
BISC36
LogT
otFl
ow
4239363330
4
3
2
1
0
-1
-2
S 0.517856R-Sq 17.9%R-Sq(adj) 17.7%
BISC36LogTotFlow = 5.548 - 0.09394 BISC36
6116 m from shore
SFWMD and Biscayne National Park GW and Salinity Plotted Together
ConclusionsBiscayne Bay was much fresher historically.
Freshwater was and is distributed through the bay bottom as groundwater and is a source of freshwater most available to benthic communities.
Total flux rates at the BK site are generally higher (2-3 times) than the MC site.
Wind speed and direction plays a role in flux magnitude, direction, source of water (re-circulated SW or freshwater), and in turn the GW WQ contributions into the Bay.
Despite large openings to the ocean the coastal environments of the bay are much fresher than expected.
Empirical data are showing that things are very different than presupposed or modeled.
Multiple empirical investigators show the same or very similar results, which are different than the operating hypotheses that have been applied to the Bay.
It is important to convene a meeting of all of the groundwater and Biscayne Bay salinity investigators to compare information and compile data in the same units and format.
Final Conclusion:
“The greatest obstacle to discovery is not ignorance –
It is the illusion of knowledge.”Daniel Boorstin
"You cannot solve problems with the same type of thinking used to create them." - Albert Einstein
Acknowledgements • Amy Renshaw• Ed Kearns• Helen Mayoral• Adam Wood• Joe Serafy• Elmar Kurzbach• Rick Alleman• Cynthia Gefvert
• National Park Service-South Florida Natural Resources Center
• U. S. Army Corps of Engineers
• Miami-Dade County DERM
• South Florida Water Management District National Park Service
