An extreme range of dry conditions in inland counties to very wet coastal counties in October demonstrated how fickle Florida’s seasonal rainfall patterns can be — and why it’s important to irrigate lawns and landscapes based on conditions in your yard. Mother Nature often will do the watering for you.
A full report outlining hydrological conditions was presented at the St. Johns River Water Management District’s November Governing Board meeting Tuesday.
Referencing data from NOAA, District staff noted coastal north Florida can expect unusually high tides beginning later this week, with the possibility of flooding in the lower St. Johns River. Tropical Storm Eta could compound flooding concerns.
October hydrologic highlights include:
- 2.13 inches of rainfall in Alachua County.
- Districtwide, October rainfall averaged 3.23 inches, more than ¾ inch below the long-term average for the month.
- Southeastern Indian River County reported very high rainfall in October, while inland areas and the western portion of the District’s 18-county region experienced drier conditions.
- Districtwide, the cumulative rainfall total over the last 12 months is 51.27 inches, which is 0.26 inch above the long-term average.
- The Tri County Agricultural Area of St. Johns, Flagler and Putnam counties have received below-average rainfall for the past 12 months.
- The District’s northernmost counties, along with Volusia and northern Brevard counties, have received above-average rainfall for the past 12 months.
- · Upper Floridan aquifer conditions (groundwater levels) at the end of October were in the high range across much of the central and southern portions of the District, while the northern portion of the District recorded conditions in the normal range.
- · Groundwater levels are at the 86th percentile districtwide. This means that since 1980, aquifer levels have been higher than they are now about 14 percent of the time.
Surface water flows
- Surface water flow conditions across most of the District were in the average range for this time of year. Exceptions are the Wekiva River, which had high flows, and the tidally influenced portion of the St. Johns River in Jacksonville, which was in the low range.
- On Nov. 1, flows in the Wekiva River near Sanford were in the high range at 229 mgd (89th percentile).
- Flows in the Ocklawaha River, the largest tributary to the St. Johns River, were 524 mgd, or in the 46th percentile.
- The DeLand station reported flows of 4.46 billion gallons per day (bgd), or in the 74th percentile, while the Satsuma station reported flows of 5.5 bgd (60th percentile).
- Flow in the Econlockhatchee River near Chuluota was 152 mgd, which is in the 66th percentile of flow conditions for the time of year.
- Flow in the headwaters at the Melbourne station was 546 million gallons per day (mgd) on Nov. 1, which is in the 52nd percentile of flow conditions for this time of year.
- Flows in the St. Marys River near Macclenny were 146 mgd (70th percentile).
- Lake Brooklyn water levels decreased slightly in October to 100.1 feet, remaining below its long-term average.
- Lake Weir decreased slightly during October to 53.1 feet.
- Lake Apopka’s water level decreased 0.2 foot since the end of September and is now consistent with its regulation schedule. Lake Apopka is part of a system with water control structures that are operated by the District to reduce flood impacts, and the lake level is regulated according to a specific schedule.
- Blue Cypress Lake levels increased to 23.1 feet during October. Blue Cypress Lake is also part of a system with water control structures that are operated by the District. 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 to 684 cubic feet per second (cfs), or 443 mgd.
- · At the Blue Spring station in Volusia County, the mean monthly flow increased to 160 cfs, or 103 mgd, which is within the high flow range for the time of year.
- · At Rock Springs, the monthly mean flow was 62 cfs (40 mgd), an increase of 2 cfs compared to September.
- · Mean monthly flow at Wekiwa Springs was 71 cfs (46 mgd), an increase of 3 cfs from September.
To learn more about rainfall totals and other hydrologic data collected, visit sjrwmd.com.
The District’s “Fall Back” message reminds homeowners to water no more than once a week as Florida enters cooler weather, corresponding with the annual change to Eastern Standard Time.
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About the St. Johns River Water Management District
St. Johns River Water Management District staff are committed to ensuring the sustainable use and protection of water resources for the benefit of the people of the District and the state of Florida. The St. Johns River Water Management District is one of five districts in Florida managing groundwater and surface water supplies in the state. The District encompasses all or part of 18 northeast and east-central Florida counties. District headquarters are in Palatka, and staff also are available to serve the public at service centers in Maitland, Jacksonville and Palm Bay.