Water Velocities and Total Suspended Solids Transport in the Southern
Everglades
Eric Jorczak and Mark Clark
University of Florida, Gainesville, FL
Changes in Everglades soil topography are regulated by physical and biological
processes. Soil topography acting with hydroperiod governs plant type and
distribution. Lower water levels in some parts of the Everglades have led to
oxidation of soils and possibly a narrowing of this topographic difference between
a ridge and slough or wet prairie. It is believed that this long-term decrease in
hydroperiod has led to sawgrass (Cladium jamaicense Crantz) colonization of
sloughs, or a conversion of sloughs into wet prairies. In order to prevent further
transformation of Everglades habitats, it is important to understand the
mechanisms affecting soil topography. Water flow may play a role in
transporting particulates through the Everglades, helping to influence soil
topography. This study measured water velocity and total suspended solids (TSS)
to estimate TSS loading rates in three habitat types (ridge, slough, and wet prairie)
in Water Conservation Area 3A (WCA 3A) and Everglades National Park (ENP).
This may help explain the role of particulate transport in shaping the soil
topography of the Everglades.
Four locations (WCA 3A1 (high flow site-2 km south of Alligator Alley), WCA
3A2 (low flow site-16 km north of Tamiami Trail), ENP1 (low flow site-east of
the L-67 extension), ENP2 (high flow site-southern Shark Slough)) were
monitored once every two months for one year, which covered a full wet and dry
season. The ENP sites had ridges adjacent to wet prairies, while WCA 3A sites
had ridges adjacent to sloughs. Visual observations of flow velocity and direction
were conducted using a dye tracer (fluorescein) over the course of one minute in
each habitat type. In addition, water depth was measured and water samples were
filtered for total suspended solids.
Results of this preliminary study are shown in Table 1. Microscopic analysis of
filter paper suggests that most particulates are diatoms, spicules, algae, and plant
fragments. All of these exist naturally in the water column, indicating they were
probably not scoured from the soil surface and brought up into the water column.
A much greater water velocity may be required to physically dislodge and
transport sediment.
Table 1. Flow velocities and TSS calculations at four Everglades sites.
Site #
11-May-02
18-Jul-02
23-Nov-02
4-Jan-03
4-Jan-03
4-Jan-03
4-Jan-03
Location and
velocity
velocity
velocity
velocity
water
TSS
TSS loads
habitat type
(cm/sec)
(cm/sec)
(cm/sec)
(cm/sec)
depth (cm)
(mg/L)
(mg/sec/m)
1
WCA3A1-ridge
no data
1.23
0.56
0.54
24
0.04
0.05
1
WCA3A1-slough
no data
1.76
0.43
0.45
39
0.42
0.73
2
WCA3A2-ridge
no data
0.46
0.14
0.01
51
0.29
0.01
2
WCA3A2-slough
no data
0.42
0.12
0.02
72
0.17
0.03
3
ENP1-ridge
0.35
no data
0.13
0.40
28
0.21
0.23
3
ENP1-prairie
0.11
no data
0.37
0.68
37
0.35
0.88
4
ENP2-ridge
no data
2.16
1.26
1.06
21
0.49
1.10
4
ENP2-prairie
no data
1.46
0.83
1.00
39
0.41
1.59
Eric Jorczak, Wetland Biogeochemistry Laboratory, Soil and Water Science
Department, 106 Newell Hall, University of Florida, Gainesville, FL 32611
Phone: (352) 392-1804 ext.343, jorczak@ufl.edu, Poster