Mill Dam (Marion County)

Florida LAKEWATCH Water Chemistry Summary

Location: Latitude 29°10'54", Longitude 81°50'27"

Period of record: 35 sampling dates; January 31, 1990 to December 7, 1999

Surface area (LAKEWATCH): 309 acres / 125 hectacres     Bathymetric Map

Lake Region (Griffith et al. 1997): Ocala Scrub

Geologic formation (Brooks 1981):

The geology is dominated by deeply weathered clayey sand and granular sand of the Hawthorne Formation.

Physiographic region (Brooks 1981):

The water body lies in the Lynne Karst division of the Central Lake District.
 
 

Supplemental, unpublished water chemistry data, University of Florida.

Numbers reported below are the average for 7 months sampled:
 
pH
6.5
 Sulfate (mg/L)
5.0
Total alkalinity (mg/L as CaCO3)
3.5
 Calcium (mg/L)
2.4
Conductance (µS/cm @ 25 °C)
49
 Magnesium (mg/L)
1.0
Color (Pt-Co units)
11
 Sodium (mg/L)
4.6
Chloride (mg/L)
10.0
 Potassium (mg/L)
0.3
Silicon (mg/L)
0.1
    

Long-term Florida LAKEWATCH Data

Numbers reported below are the minimum, average, and maximum value for the 35 months sampled:

 
Minimum
Average
Maximum
Long-term total phosphorus concentrations (µg/L)
7
14
43
Long-term total nitrogen concentrations (µg/L)
410
540
760
Long-term total chlorophyll concentrations (µg/L)
2.0
4.7
10.7
Long-term Secchi depth (ft)
4.3
7.0
14.7

1999 Florida LAKEWATCH Data

Numbers reported below are monthly averages calculated from 3 stations for total phosphorus (TP, µg/L), total nitrogen (TN, µg/L), chlorophyll (CHL, µg/L) and Secchi depth (SECCHI, ft) during 1999:

Date
TP (µg/L)
TN (µg/L)
CHL (µg/L)
SECCHI (ft
Apr-20-99
12
500
3.3
5.7
May-12-99
11
490
3.3
7.9
Jun-22-99
10
430
3.3
8.6
Aug-09-99
10
500
5.0
6.7
Dec-07-99
11
450
4.0
7.8
         
1999 Average
11
470
3.8
7.3

Mill Dam (Marion County)

Florida LAKEWATCH Aquatic Plant Summary

Aquatic plant data collected on May 23, 1991

Percent area covered with aquatic vegetation (PAC, %)
6
Percent of lake's volume filled with vegetation (PVI, %)
1
Average emergent plant biomass (kg wet wt/m2)
1.3
Average floating-leaved plant biomass (kg wet wt/m2)
1.3
Average submersed plant biomass (kg wet wt/m2)
0.0
Average width of emergent and floating-leaved zone (ft.)
10
Average lake depth (m)
4

Frequency that plant species occur in 10 evenly spaced transects around the lake.

Common Name Plant Species
Frequency (%)
maidencane Panicum hemitomon
90
spatterdock Nuphar luteum
60
banana-lily Nymphoides aquatica
40
pickerelweed Pontederia cordata
30
smartweed Polygonum hydropiperoides
10

Mill Dam (Marion County)

Florida LAKEWATCH Aquatic Plant Summary

Aquatic plant data collected on June 30, 1992

Percent area covered with aquatic vegetation (PAC, %)
0
Percent of lake's volume filled with vegetation (PVI, %)
0
Average emergent plant biomass (kg wet wt/m2)
0.6
Average floating-leaved plant biomass (kg wet wt/m2)
0.5
Average submersed plant biomass (kg wet wt/m2)
0.0
Average width of emergent and floating-leaved zone (ft.)
156
Average lake depth (m)
4

Frequency that plant species occur in 10 evenly spaced transects around the lake.

Common Name Plant Species
Frequency (%)
maidencane Panicum hemitomon
80
spatterdock Nuphar luteum
60
water-pennywort Hydrocotyle umbellata
60
red ludwigia Ludwigia repens
30
buttonbush Cephalanthus occidentalis
30
rush fuirena Fuirena scirpoidea
30
St. John's wort Hypericum spp.
30
sawgrass Cladium jamaicense
20
red root Lachnanthes caroliniana
20
slender spikerush Eleocharis baldwinii
10
smartweed Polygonum hydropiperoides
10
pickerelweed Pontederia cordata
10
lemon bacopa Bacopa caroliniana
10
jointed flat sedge Cyperus haspan
10

Mill Dam (Marion County)

Florida LAKEWATCH Aquatic Plant Summary

Aquatic plant data collected on May 24, 1994

Percent area covered with aquatic vegetation (PAC, %)
6
Percent of lake's volume filled with vegetation (PVI, %)
1
Average emergent plant biomass (kg wet wt/m2)
0.8
Average floating-leaved plant biomass (kg wet wt/m2)
0.7
Average submersed plant biomass (kg wet wt/m2)
0.0
Average width of emergent and floating-leaved zone (ft.)
52
Average lake depth (m)
4

Frequency that plant species occur in 10 evenly spaced transects around the lake.

Common Name Plant Species
Frequency (%)
water-pennywort Hydrocotyle umbellata
80
salt-bush Baccharis spp.
70
spatterdock Nuphar luteum
60
maidencane Panicum hemitomon
50
rush fuirena Fuirena scirpoidea
50
slender spikerush Eleocharis baldwinii
40
yellow-eyed grass Xyris spp.
40
respuinata bladderwort Utricularia resupinata
40
jointed flat sedge Cyperus haspan
40
pickerelweed Pontederia cordata
30
wax myrtle Myrica cerifera
20
St. John's wort Hypericum spp.
20
red root Lachnanthes caroliniana
20
duck-potato Sagittaria lancifolia
10
banana-lily Nymphoides aquatica
10
red ludwigia Ludwigia repens
10
water primrose Ludwigia octovalvis
10
buttonbush Cephalanthus occidentalis
10
sawgrass Cladium jamaicense
10
para grass Brachiaria mutica
10
torpedograss Panicum repens
10
elderberry Sambucus canadensis
10

Mill Dam (Marion County)

Florida LAKEWATCH Aquatic Plant Summary

Aquatic plant data collected on May 12, 1999

Percent area covered with aquatic vegetation (PAC, %)
16
Percent of lake's volume filled with vegetation (PVI, %)
2
Average emergent plant biomass (kg wet wt/m2)
8.7
Average floating-leaved plant biomass (kg wet wt/m2)
3.0
Average submersed plant biomass (kg wet wt/m2)
1.5
Average width of emergent and floating-leaved zone (ft.)
163
Average lake depth (m)
4

Frequency that plant species occur in 10 evenly spaced transects around the lake.

Common Name Plant Species
Frequency (%)
pickerelweed Pontederia cordata
100
bacopa Bacopa monnieri
100
fragrant water-lily Nymphaea odorata
90
banana-lily Nymphoides aquatica
80
buttonbush Cephalanthus occidentalis
80
sawgrass Cladium jamaicense
80
maidencane Panicum hemitomon
80
slender spikerush Eleocharis baldwinii
70
spatterdock Nuphar luteum
70
St. John's wort Hypericum spp.
70
red ludwigia Ludwigia repens
60
bog-moss Mayaca fluviatilis
60
wax myrtle Myrica cerifera
50
cordgrass Spartina bakeri
50
pipewort Eriocaulon spp.
40
respuinata bladderwort Utricularia resupinata
40
water-pennywort Hydrocotyle umbellata
30
cone-spur bladderwort Utricularia gibba
30
rush fuirena Fuirena scirpoidea
30
. Nitella prolonga
30
duck-potato Sagittaria lancifolia
20
water-shield Brasenia schreberi
20
purple bladderwort Utricularia purpurea
20
willow Salix spp.
20
red root Lachnanthes caroliniana
20
bladderwort Utricularia foliosa
20
red maple Acer rubrum
20
water sprite Ceratopteris thalictroides
10
smartweed Polygonum hydropiperoides
10
dwarf arrowhead Sagittaria subulata
10
variable-leaf milfoil Myriophyllum heterophyllum
10
salt-bush Baccharis spp.
10
torpedograss Panicum repens
10
yellow-eyed grass Xyris spp.
10
jointed flat sedge Cyperus haspan
10

Mill Dam (Marion County)

Electrofishing Data


     
Canfield and Hoyer (1992) Ranges
Species1
#/hr
kg/hr2
min weight (kg/hr)
mean weight (kg/hr)
max weight (kg/hr)
Bluegill
20
1.4
0.3
50.3
447
Bowfin
2
2.3
3
54.5
225
Brook silverside
119
0.2
0
0.2
1.4
Brown bullhead
5
2.8
0.1
14.5
72.1
Florida gar
12
4.3
0.8
50.1
328.6
Golden shiner
170
2
0
6.9
65
Lake chubsucker
48
15.8
0.1
40.7
161.9
Largemouth bass
78
24.3
1.1
82
284.6
Redear sunfish
33
0.9
0.1
24.3
183.1
Warmouth
5
0.3
0
1.5
12
Yellow bullhead
7
2.2
0
2.2
7.2
           
Total
499
56.5
      

 

1 Total # of species = 11.
2 Weights calculated using regressions from Hoyer and Canfield 1994 and from Bill Schaeffer, Florida Fish and Wildlife Conservation Commission (personal communication).
 



Catch per unit of effort (kg of fish / hour of sampling) versus total chlorophyll (mg/m3) and number of fish species collected versus surface area of lake for 60 Florida lakes sampled by Canfield and Hoyer (1992) (•) and Lake Mill Dam (Marion County) electrofishing sampling (o). The lines represent linear regressions for logged values of the 60 Florida lakes.
 
 

Mill Dam (Marion County)

Trawl Data

Species
Size Group
Mean CPM
Range of TL (mm)
1998
 
bluegill
all
10.89
39 - 152
bluegill
318 cm
0
-
gizzard shad
all
0.13
132 - 312
largemouth bass
all
0.13
142 - 152
redear
all
0.03
93
redear
318 cm
0
-
1999
 
bluegill
all
3.17
20 - 193
bluegill
318 cm
0.06
-
brown bullhead
all
0.22
372 - 415
channel catfish
all
0.06
541
Florida gar
all
0.22
404 - 519
lake chubsucker
all
0.11
321 - 331
largemouth bass
all
0.11
246 - 269
redear
all
1.99
154 - 245
redear
318 cm
1.6
  

 

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