Aquifer Resource Weekly Update: October 4, 2006

The Southwest Florida Water Management District's Aquifer Resource Weekly Update provides information to the public about the health of the water resources.

Aquifers are underground layers of rock and sand that hold water. In southwest Florida, more than 80 percent of the water supply comes from aquifers.

The Aquifer Resource Weekly Update contains two sections: Aquifer Levels and Rainfall. Levels and rainfall are provided for three regions: north (Citrus, Hernando, Lake, Levy, Marion and Sumter counties), central (Hillsborough, Pasco, Pinellas, and Polk counties), and south (Charlotte, DeSoto, Hardee, Highlands, Manatee, and Sarasota counties). Aquifer Levels and Rainfall will be updated weekly.

Aquifer levels normally fluctuate from month to month, reaching annual high levels at the end of the rainy season, and annual low levels at the end of the dry season. Therefore, each month has a different range of normal readings. The Aquifer Levels table compares current average levels to the lowest historical normal averages for the given month. For example, January 2006 readings are compared with records from all previous Januarys. The numeral "0" represents the bottom of the normal range of readings. A positive (+) number means the current average levels are normal or above normal. For instance, a "+1" reading means the current levels average a foot above the bottom of the normal range. A negative (-) number indicates the current levels are below normal.

The weekly aquifer level table shows how the current average levels compare to the bottom of the normal range, the comparison to last week's average level and the level measured on the same date last year, and the range of normal values for each region. For example, in the northern region any value between "0" and "+4" would be considered to fall within the normal range. A value greater than "+4" in the northern region would be above the normal range.

Aquifer Levels

*Approximate levels

The Rainfall tables show the rainfall measured since January 1, 2006, the historic average for this period, the annual totals for recent years and the historic annual average for the entire period of record for the three regions. The rainfall values for the current month and year are considered provisional and subject to revision. The other annual figures are final.

2006 Rainfall (in inches)

Historic Rainfall (Jan. - Dec. in inches)