Live Oak —
So, just how much rain are we getting and how does it affect the aquifer? According to data released by the Suwannee River Water Management District (District), average rainfall across the District through July 24 was 10.8 inches, the wettest July in 30 years and the 8th rainiest since 1932. Rainfall was the result of both typical convective summer storms and stalled fronts caused by a persistent trough of low pressure over the southeast U.S.
Average rainfall through July 24 in Dixie County was 16 inches, almost double the long-term July average. The radar estimate over Cross City was around 18 inches. This is the highest total for Cross City since 1980, which saw 20.5 inches, and the third highest total since record-keeping began in 1948. The highest gaged total was 17.4 inches at Wacissa Tower near Wacissa, about two and a half times a typical July in Jefferson County. The “rainiest” gage was at Rosewood Tower near Cedar Key, where it rained 23 of the last 24 days.
Rainfall totals diminished away from the coastal counties, but even the lowest county averages were typical of July.
Area rivers were already high after flooding this spring. River conditions everywhere are much above normal for this time of year, with minor flooding on the Steinhatchee, Aucilla, and Santa Fe rivers. Rainfall totals have been typical of the season in upper Suwannee tributary basins, so levels on the Suwannee should stay below flood stage unless more organized weather moves in.
July is typically the wettest month of the year, but also one of the hottest. Typical July rainfall is not as effective at recharge as rain in cooler months, because so much of it evaporates and is taken up by vegetation. This is why aquifer levels usually fall in the summer despite rainfall that would cause serious flooding if it fell in the winter months.
In areas with extreme rainfall this month, groundwater levels responded well, with at least two wells in Lafayette and Dixie counties setting record high levels based on records beginning in the 1980s. Levels in eastern counties where totals were more typical of July saw aquifer levels remain stable or improve slightly. Wells in eastern Levy and western Alachua counties, which have been below normal for most of the last seven years, started inching upward after falling steadily since last summer. Overall, levels across the District have been improving since May.
The long-term outlook through the first week of August indicates a ridge of high pressure building over the southern U.S., which will cause generally drier conditions with typical afternoon scattered thunderstorms. However, the peak of tropical storm season is right around the corner. A tropical system hitting our area with already elevated river levels could cause serious flooding.