Keystone (Hillsborough County)
Florida LAKEWATCH Water Chemistry Summary
Location: Latitude 28°8'3", Longitude 82°35'23"
Period of record: 79 sampling dates; August 31, 1990 to December 16, 1999
Surface area (Shafer et al. 1986): 417 acres / 169 hectacres
Lake Region (Griffith et al. 1997): Keystone Lakes
Geologic formation (Brooks 1981):
The geology is dominated by argillaceous to sandy impure limestone of the Tampa Formation.
Physiographic region (Brooks 1981):
The water body lies in the Land-O-Lakes subdivision of the Tampa Plain division of the Ocala Uplift District.
Supplemental, unpublished water chemistry data, University of Florida.
Numbers reported below are the average for 2 months sampled:
|
pH |
6.3 |
Sulfate (mg/L) |
13.8 |
|
Total alkalinity (mg/L as CaCO3) |
2.3 |
Calcium (mg/L) |
5.5 |
|
Conductance (µS/cm @ 25 °C) |
100 |
Magnesium (mg/L) |
2.0 |
|
Color (Pt-Co units) |
30 |
Sodium (mg/L) |
8.5 |
|
Chloride (mg/L) |
17.5 |
Potassium (mg/L) |
2.0 |
|
Silicon (mg/L) |
0.5 |
|
|
Long-term Florida LAKEWATCH Data
Numbers reported below are the minimum, average, and maximum value for the 79 months sampled:
|
|
Minimum |
Average |
Maximum |
|
Long-term total phosphorus concentrations (µg/L) |
5 |
10 |
26 |
|
Long-term total nitrogen concentrations (µg/L) |
330 |
500 |
670 |
|
Long-term total chlorophyll concentrations (µg/L) |
1.0 |
4.0 |
12.7 |
|
Long-term Secchi depth (ft) |
4.0 |
8.8 |
16.0 |
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 |
|
Jan-12-99 |
9 |
540 |
3.0 |
8.6 |
|
Feb-16-99 |
12 |
600 |
2.0 |
8.7 |
|
Mar-16-99 |
11 |
570 |
2.7 |
7.3 |
|
Apr-13-99 |
15 |
560 |
6.3 |
8.8 |
|
May-13-99 |
18 |
590 |
6.3 |
8.2 |
|
Jun-15-99 |
20 |
670 |
12.7 |
7.5 |
|
Jul-13-99 |
16 |
530 |
9.7 |
8.5 |
|
Aug-17-99 |
15 |
480 |
9.3 |
9.0 |
|
Sep-16-99 |
11 |
440 |
5.3 |
9.8 |
|
Oct-12-99 |
8 |
410 |
5.0 |
12.0 |
|
Nov-16-99 |
9 |
660 |
3.0 |
11.3 |
|
Dec-16-99 |
9 |
510 |
3.0 |
9.2 |
|
|
|
|
|
|
|
1999 Average |
13 |
550 |
5.7 |
9.1 |
Keystone (Hillsborough County)
Florida LAKEWATCH Aquatic Plant Summary
Aquatic plant data collected on June 18, 1992
|
Percent area covered with aquatic vegetation (PAC, %) |
28 |
|
Percent of lake's volume filled with vegetation (PVI, %) |
3 |
|
Average emergent plant biomass (kg wet wt/m2) |
3.7 |
|
Average floating-leaved plant biomass (kg wet wt/m2) |
2.1 |
|
Average submersed plant biomass (kg wet wt/m2) |
3.1 |
|
Average width of emergent and floating-leaved zone (ft.) |
18 |
|
Average lake depth (m) |
3 |
Frequency that plant species occur in 20 evenly spaced transects around the lake.
|
Common Name |
Plant Species |
Frequency (%) |
|
bog-moss |
Mayaca fluviatilis |
95 |
|
torpedograss |
Panicum repens |
75 |
|
slender spikerush |
Eleocharis baldwinii |
70 |
|
bald cypress |
Taxodium distichum |
70 |
|
Florida bladderwort |
Utricularia floridana |
65 |
|
pickerelweed |
Pontederia cordata |
50 |
|
maidencane |
Panicum hemitomon |
50 |
|
banana-lily |
Nymphoides aquatica |
45 |
|
water primrose |
Ludwigia octovalvis |
45 |
|
fragrant water-lily |
Nymphaea odorata |
40 |
|
lemon bacopa |
Bacopa caroliniana |
40 |
|
water-pennywort |
Hydrocotyle umbellata |
30 |
|
purple bladderwort |
Utricularia purpurea |
30 |
|
common salvinia |
Salvinia rotundifolia |
25 |
|
elephant-ear |
Colocasia esculenta |
25 |
|
Baldwin flat sedge |
Cyperus globulosus |
20 |
|
spatterdock |
Nuphar luteum |
15 |
|
variable-leaf milfoil |
Myriophyllum heterophyllum |
15 |
|
red ludwigia |
Ludwigia repens |
10 |
|
southern naiad |
Najas guadalupensis |
10 |
|
stonewort |
Nitella spp. |
10 |
|
water spikerush |
Eleocharis elongata |
10 |
|
jointed flat sedge |
Cyperus haspan |
10 |
|
dwarf arrowhead |
Sagittaria subulata |
5 |
|
hydrilla |
Hydrilla verticillata |
5 |
|
variableleaf pondweed |
Potamogeton diversifolius |
5 |
|
Illinois pondweed |
Potamogeton illinoensis |
5 |
|
buttonbush |
Cephalanthus occidentalis |
5 |
|
southern water-grass |
Hydrochloa caroliniensis |
5 |
|
musk-grass |
Chara spp. |
5 |
|
rush fuirena |
Fuirena scirpoidea |
5 |