Horizontal Ground-Water Flow Velocities

Ground-water flow velocities were higher at ENR than WCA-2A by approximately a factor of 6 and 4 in intermediate and deeper layers during the wet season, respectively (table 13). During the dry season, flow rates were approximately an order of magnitude higher in ENR compared with WCA-2A (table 13). If vertical mixing in the Surficial aquifer is ignored (as a first-order assumption), and if all recharge is assumed to occur at the headwater canal adjacent to the levee, the velocities presented in table 13 are consistent with horizontal travel times on the order of hundreds of years beneath ENR and thousands of years beneath WCA-2A. Those estimates of travel time are useful as general indicators of flow, although they are unlikely to accurately reflect the actual ground-water ages because recharge in the wetland interior and vertical mixing are not considered. Although realistic calculations of the ground-water travel time are desirable, those are difficult to compute with confidence at the present time because the spatial distribution of recharge across the wetland and the extent of vertical mixing in the aquifer is still not well enough known.