PWMRWSA November 2011
RV Griffin Reserve Land Use and Management Plan Page 12
Today, these two off-stream reservoirs and the network of 21 ASR wells function in concert to
meet public supply demands during frequent periods of low river flow. Such conditions are not
unusual during the dry season, when flows in the Peace River decline and the public's demand
for water increases in response to an influx of seasonal residents and residential irrigation.
However, river flow often exceeds 1 billion gallons per day during the typical summer wet
season, making the Peace River one of the most productive sources of fresh surface water in
Southwest Florida. With current storage capacity, the system provides a reliable, year-round
source of potable water to the Authority’s customers within the region.
Water Quality
The general topography of the Reserve land serves as a natural drainage divide between the
Peace River and Myakka River watersheds. Historically, agricultural land uses have
predominated the land use and activities of the Reserve. Even today, such agricultural uses,
particularly cattle grazing, are prevalent on lands surrounding the property, as well as a portion
of the Reserve land itself.
Typical of most land used for cattle grazing and row crops in this geographic area, the Reserve’s
land also experienced these types of alterations all occurring prior to the District’s acquisition of
the property. Drainage enhancements designed to improve grazing conditions and crop
production in uplands that were subject to seasonal flooding included the excavation of a
network of drainage ditches, which has also accelerated the drainage of some on-site wetlands.
While nutrient loading in drainage from such lands may often become elevated in response to
contact with animal wastes or land application of fertilizer, the ability of natural areas,
particularly wetlands, to provide for the natural treatment of contaminated or degraded water
runoff is widely recognized. Although some of the on-site wetlands are isolated systems, many
others are part of a loosely-linked network that receives drainage from off-site east of the
property, flows through the Reserve and eventually discharging to other off-site, down-gradient
wetlands west and south of the property. The Reserve’s numerous wetlands and freshwater
marshes filter surface water sediments and nutrients through the assimilation or metabilization of
waterborne pollutants (SWFWMD, RV Griffin Reserve LUMP, 1996).
As described above, land alterations by previous property owners had served to drain wetlands
located within the Reserve. Through the design and permitting process associated with the
Authority’s construction of a new 6 billion gallon reservoir on the Reserve land, it was
determined that hydrologic restoration and enhancement of existing on-site drained wetlands was
the most preferable and cost–effective form of mitigation for the wetland impacts associated with
the reservoir construction. The restoration project consisted of enhancing the existing wetlands
and restoring historic wetlands that had been previously converted to upland. This would be
accomplished by re-hydrating the wetlands, which has resulted in restored water levels and
restored wetland hydroperiods to more natural conditions typically found prior to land use
alterations. Hydrologic restoration methods were determined by identifying those wetlands that,
when hydrologically enhanced and restored, would provide the greatest long term benefits.
To improve the hydroperiod of the wetlands, 43 hardened control structures, and 37 ditch blocks,
were strategically placed throughout the mitigation area. Also included in this work was the
removal of 37 berm areas and ditch blocks located within the mitigation wetland sloughs. In
addition, a total of 33,275 feet of roadway that restricted water sheetflow were removed from