An aquifer test was reanalyzed to estimate the hydraulic properties of the surficial aquifer system, which was divided into two geohydrologic units—the upper zone and the lower zone. The effect of evapotranspiration from a forested area was investigated. The analysis of ground-water flow and potential movement of contaminants within the surficial aquifer system was addressed using the calibrated model driven by a uniform recharge rate of 19 inches per year and an evapotranspiration rate of 30 inches per year from the forested area. These recharge conditions were used to simulate the advective movement of conservative contaminants through area C with MODPATH for all remedial alternatives.
Under existing conditions, phytoremediation alone at area C at Orlando Naval Training Center cannot stop the discharge of contaminants into Lake Druid because within the analyzed control volume the evapotranspirative losses (3.7 gallons per minute) are small relative to the ground-water.
discharge to Lake Druid (20.4 gallons per minute). The installation of a drainage ditch could redirect flow through the rooting zone of aquatic plants which would remediate the ground-water discharge. A drainage ditch would intercept flow from 0 to about 40 feet below the water table but would still allow water in the lower 20 feet of the surficial aquifer system to continue to discharge to Lake Druid.