Rainy October in coastal areas while inland counties were dry

“Fall Back” to watering lawns no more than once a week

A map illustrates rainfall conditions in October across the St. Johns River Water Management District.

PALATKA, Fla., Nov. 10, 2020 — 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:

Rainfall

• 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.

Groundwater

• 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 86^th 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 (89^th percentile).
• Flows in the Ocklawaha River, the largest tributary to the St. Johns River, were 524 mgd, or in the 46^th.
• The DeLand station reported flows of 4.46 billion gallons per day (bgd), or in the 74^th percentile, while the Satsuma station reported flows of 5.5 bgd (60^th percentile).
• Flow in the Econlockhatchee River near Chuluota was 152 mgd, which is in the 66^th 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 52^nd percentile of flow conditions for this time of year.
• Flows in the St. Marys River near Macclenny were 146 mgd (70^th percentile).

Lake levels

• 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.

Spring flows

• The mean monthly flow at Silver Springs increased to 684 cubic feet per second (cfs), or 443
• 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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