Our May Lake of the Month is Lake Persimmon (set your GPS to 27.3550
-81.4054). The elevation of Lake Persimmon is 68’.
To view of bathymetric map of Lake Persimmon please visit:
http://lakewatch.ifas.ufl.edu/RevisedMaps05/HighlandsMaps/PersimmonHighlandsMap.
pdf
Lake Persimmon is located 5 miles north of Lake Placid in Highlands County. The
maximum depth for Lake Persimmon is 11’ while the average depth is 4.4’. Lake
Persimmon drains into Josephine Creek and eventually Lake Istokpoga. The only inflows
are from rainfall, stormwater runoff, and underground seepage.
Lake Persimmon is 44 acres in size and is considered a muck lake.
Let’s go fishing. If you like fishing, Lake Persimmon is reported to support populations
of largemouth bass, bluegill, and crappie. Highlands County’s Parks and Natural
Resources Department maintains one boat ramp on Lake Persimmon; located at 150
Hillside Drive. While there is parking for vehicles with trailers, there are no facilities.
There is a trash receptacle and a mono-filament recycling bin. Please be sure to put all
unwanted fishing line in the bin for recycling. Fishing line left in the lake kills.
The water quality of Lake Persimmon is very poor compared to most lakes in the
county. A study in 2000 showed that the Highlands County lake experiences continual
blooms of blue-green algae and long periods of anoxia at the bottom and middle depths
of the lake. Anoxia is the lack of oxygen resulting from dense algae in the lake. The algae
blocks light penetration below the surface, inhibiting growth of desirable plants and
causing the lake to separate into different temperature layers. The layers include a warm
layer on the surface and a cold layer on the bottom, which is dark and depleted of
oxygen. In Lake Persimmon, the anoxia is accompanied by a buildup of toxic ammonia
and hydrogen sulfide in the water
Excess nitrates are brought into the lake by contaminated ground water. The primary
source of the nitrates is from years of application of fertilizers within citrus groves and
residential lawns surrounding the lake. Sampling results of both shallow test wells and
residential drinking wells revealed elevated nitrates, sometimes three times the
Environmental Protection Agency’s (EPA) drinking water standard. As the contaminated
ground water seeps into Lake Persimmon, it ignites blue-green algae blooms, while
excess nitrates are converted to toxic ammonia in the anoxic bottom waters.
In an attempt to eliminate the high concentrations of ammonia and hydrogen sulfide in
the lake, a lake aeration system was attempted. Eleven air diffusers were placed at
various points around the bottom of the lake. The air being pumped into the bottom
breaks up the anoxic layer and eliminates the vicious cycle of ammonia and hydrogen
sulfide production. Ending the anoxia in the lake also prevents the release of nutrients
from the mucky bottom sediments, which also helps reduce algae growth. The aeration
system was installed in July 2002. Initially the lake showed huge increases in Secchi disk
readings going from 6” visibility to about 4’. Two months later however the water clarity
dropped to 1’. In addition to some improvements in water clarity the lake experienced a
substantial decrease in ammonia and some sign of water quality improvement, including
a reduction in nitrates and blue-green algae. In 2003 continuing equipment failures
caused the project to be abandoned.
The next step to restoring Lake Persimmon will be working with the citrus growers and a
nursery in the watershed to ensure that best management practices are used (regarding
fertilizers) to reduce nitrates.
Lake Persimmon, Florida.