Lake Persimmon Water Quality Study

Lake Persimmon is a 44 acre, hypereutrophic, shallow (10 feet) 'transition' type lake surrounded by muck soils.  Water quality in Lake Persimmon is very poor compared to most lakes in the county (and the state) and frequent resident complaints about repeated algae blooms initiated a cooperative study between the Southwest Florida Water Management District and Highlands County.  The purpose of the study is to determine the source of the excessive nutrient levels in the lake and to determine the course of action necessary to improve water quality.  The tasks to be completed to accomplish this goal are briefly outlined here.

Intensive monthly water quality monitoring is being conducted on Lake Persimmon at this time - samples are taken from the surface and the bottom in the lake and in the canal that has been dug.  Nutrient levels measured in the canal in the past were ten times higher than nutrient levels in the lake and part of this study will investigate the true nature of the influence this canal has on water quality in the lake.  A paleolimnological study conducted by the University of Florida used a sediment core to determine that the type of nitrogen and the amount of nitrogen entering the lake has changed in recent decades.  Groundwater monitoring wells will be used to determine whether significant amounts of nitrate are moving towards the lake through the horizontal flow of shallow groundwater.  More precise ground water flow patterns will be determined for the entire watershed through the installation of additional monitoring wells.  Sources of nutrients will also be identified in this study.

A Lake Persimmon Restoration Committee has recently formed and committee members have been meeting to determine a course of action to take for restoration of water quality in the lake.  An aeration system was installed in the lake in July of 2002 as a temporary means of improving lake water quality.  Water clarity in the lake improved significantly during January 2003, when secchi depths (a measure of how deep the water is clear) went from six inches to an astounding four feet; however, water clarity dropped again to about 1 foot of clarity within about two moths, where it remains as of November 2003.  Some water quality parameters have improved, but the lake itself is NOT 'fixed.'  Much work remains to be done to eliminate the sources of incoming nutrients and to establish a healthy plant population around the lake.

The committee will continue to review other restoration options and select enhancement projects best suited to reduce nutrient loading into the lake from the watershed.  The committee will review watershed management initiatives, including:

In lake restoration options that will be considered, at least initially, include: