Along with the threat of a hurricane at the end of July, some portions of the St. Johns River Water Management District received copious rainfall — like Volusia County — while rainfall recorded in some north Florida counties was one to two inches below average.
A full report outlining hydrological conditions was presented at the district’s August Governing Board meeting. Highlights included:
- Districtwide, July rainfall was 7.27 inches, slightly above the long-term average.
- July rainfall varied geographically by region. The district’s northern counties received below-average rainfall last month. Central and southern counties were near or above average in rainfall.
- The county with the greatest July rainfall was Volusia, where some areas received more than a foot of rain.
- Districtwide, the cumulative rainfall total over the last 12 months is 48.4 inches, which is 2.6 inches below the long-term average.
- Counties with the greatest rainfall deficit through July were Putnam, Flagler and St. Johns counties, which have received less than 43 inches of rain over the last 12 months. These counties have been maintaining a deficit of 9 inches or more since March.
- · Upper Floridan aquifer conditions (groundwater levels) at the end of July were mostly in the normal range throughout most of the district. However, parts of Alachua County and the northern portion of Brevard County recorded high levels.
- · Aquifer conditions in parts of northern St. Johns and southeastern Duval recorded low levels.
- · Groundwater levels are at the 63rd percentile districtwide. This means that since 1980, aquifer levels have been higher than they are now about 37 percent of the time.
Surface water flows
- Surface water flow conditions in the St. Johns River’s headwaters and the Middle St. Johns River Basin were in the average range for this time of year.
- Flow in the headwaters at the Melbourne station was 480 million gallons per day (mgd) on Aug. 1, which is in the 59th percentile of flow conditions for this time of year.
- Flow conditions in central Florida were in the high range, with the DeLand station reporting 2.66 billion gallons per day (bgd) on Aug. 1 and the Satsuma station reporting 5.8 bgd.
- Flow in the Econ River was in the high range (612 mgd), while the Ocklawaha, Wekiva and St. Marys rivers were in average ranges for this time of year.
- Lake Brooklyn water levels decreased 0.24 foot in July.
- Lake Weir increased 0.24 foot during July.
- Lake Apopka’s water level increased 0.25 foot and is appropriate for its regulation schedule for July.
- Blue Cypress Lake levels increased temporarily but ended the month level at 21.6 feet, within its regulation schedule for July. Keeping water levels low in the Upper St. Johns River Basin helps the district prepare for greater rainfall during the tropical season.
- · The mean monthly flow at Silver Springs increased slightly to 646 cubic feet per second (cfs), or 417 mgd.
- · At the Blue Spring station in Volusia County, the mean monthly flow was recorded at 151 cfs, or 98 mgd, which is within the normal range for the time of year.
- · At Rock Springs, the monthly mean flow was 59 cfs (38 mgd), and mean monthly flow conditions at Wekiwa Springs was 64 cfs (41 mgd).
To learn more about rainfall totals and other hydrologic data collected, visit sjrwmd.com.