Alafia River Minimum Flows and Levels - Southwest Florida Water ...

candidate for demonstrating mining impacts related to increased area of mined
land was sound, in that, given the relatively larger increase in mined area since
1963 and the relative lack of other land use changes, one should expect to see a
flow impact if increasing area of lands mined does in fact lead to decreases in
stream flow. However, this was not the case. The remarkably similar discharges
evident between the two watersheds despite relatively large differences in
percent of land disturbed by mining suggests that these watersheds have
tolerated considerable land disturbance without appreciable changes in flow as
measured at USGS gage sites. Inspection of these decadal plots further
suggests that the timing and seasonality of flows was not appreciably affected
either. As a final check various annual percent exceedance flows per unit area
(cfs/square mile) are compared in Figure 2-24. With the possible exception of
the lowest flows plotted (annual 90% exceedance flows), examination of these
plots suggests that mining may have lead to slightly increased flow. Again, if SDI
(2003) is correct, one should expect to see a substantially greater reduction in
flow when the South Prong is compared to the North Prong, this is not the case.
2-53