Water-budget analyses to calculate actual evapotranspiration in 8 basins in east-central and northeast Florida from 2000 to 2017

Actual evapotranspiration (AET) annual rates, from 2000 to 2017, for the Simplified Surface Energy Balance operational (SSEBop) method and from 2000 to 2016 for the land-cover based method, provided in shapefiles AET_SJR_Basin_Cells, are explained in the metadata file AET_SJR_Basins. The calculation of the annual average AET rates using a water-budget analysis (WBA) is explained in this metadata file referring to csv files for the eight basins in east-central and northeast Florida. A comparison of the average annual SSEBop AET rates and those derived from the WBA is then possible by using the average annual AET rates for each basin. The eight basins for which the WBA analysis was completed are: 1. St. Johns near Christmas basin (number 02232500), 2. Econlockhatchee River basin (number 02233484), 3. Wekiva River basin (number 02235000), 4. Eau Gallie River basin (number 02249007), 5. South Prong at St. Sebastian River basin (number 02251000), 6. Black Creek basin (number 02245500), 7. North Fork Black Creek basin (number 02246000), and 8. Deep Creek basin (number 02245260). The locations of these basins are shown in the shapefiles AET_SJR_Basin_Cells. Average annual rainfall (Rainfall), average annual net stream outflow (NetOutflow), average annual downward leakage from the surficial aquifer (Leakage) to the underlying hydrogeologic unit, net annual changes in storage calculated from measured water levels in surficial aquifer wells (Sydh/dt), and total annual return flow to land surface through irrigation and other water uses (Return_Flow) for all 8 basins were used to calculate the AET from the water-budget balance equation WB_AET = Rainfall – NetOutflow – Leakage -Sydh/dt + Return_Flow. Note that parameter Leakage is negative for discharge areas of the surficial aquifer. The results of the WBA method provided average annual AET rates for each basin, which can be compared with calculated annual averages from the SSEBop method for each entire basin, all rates in inches per year. The Return Flow estimates were obtained from the publication Marella, R.L., 2014, Water withdrawals, use, and trends in Florida, 2010: U.S. Geological Survey Scientific Investigations Report 2014-5088, 59 p., http://dx.doi.org/10.3133/sir20145088.