City of Polk City Water Use Permit Modification

The City of Polk City has a population of approximately 2,500 persons and a utility service area of approximately 44 square miles located in north central Polk County. In order to meet the rapid expansion of residential growth in Central Florida and their service area in particular, the City of Polk City sought to modify their existing Southwest Florida Water Management District (SWFWMD) water use permit (WUP).

We serve as an Engineer for the City of Polk City (City) and recently successfully modified the City’s WUP. Our WUP services as City Engineer included:

Computerized mapping and delineation of existing permitted withdrawals (public supply, irrigation, etc.) and associated service areas;
Identification of potential existing withdrawals that may be utilized as offsets to increased pumping from City wells;
Assessment of potential offsets based on existing permitted quantity and AGMOD (SWFWMD software used to determine the amount of irrigation required for a given irrigation area and crop) projected irrigation requirements;
Compilation of a water conservation plan identifying options to meet water conservation goals and objectives;
Projection of future water demand based on U.S. Census data and City supplied information regarding future development;
Assessment of the influence of historic pumping on local lake levels through a study that compared SWFWMD rainfall, lake level, and aquifer level data;
Environmental impact analysis via groundwater modeling utilizing MODFLOW groundwater modeling software and SWFWMD’s District Wide Regulation Model (DWRM); and
Coordinated environmental monitoring requirements with SWFWMD environmental staff.

Envisors submitted the City’s WUP modification in October 2005, and the City’s modified permit was approved in April 2007. The City received an approximate 200% increase to their WUP, from approximately 0.32 MGD AAD to 0.97 MGD AAD.