Abstract
Most of the 10,000 urban wet stormwater ponds found in southwest Florida were constructed post 1980 to protect State waters. Ideally, the impounded polluted water runoff is detained, phyto-remediated and released at the right time at mandated acceptable pollutant levels to the above and underground hydrosystems. However, most studies seem to show the poor performance for these ponds to treat surface runoffs while their groundwater connection is very largely overlooked. This one-year study examined, at high spatiotemporal resolution, the groundwater seepage nutrient loading of a 0.47 ha karstic wet detention pond which is nutrient rich despite a small mostly pervious underused watershed. This 7,000 m super( 3) water body behaved as a seepage pond (i.e. the pond did not overall recharge the aquifer) with groundwater fluxes typical of other lakes in Florida. Fluxes were positively correlated with rainfall during the dry season but not during the rainy season. Higher fluxes in the northeastern portion than in the southwestern portion were in agreement with the subsurface flow pattern in the region. Groundwater nutrient concentrations were high for total phosphorus and typical for total nitrogen. Groundwater nutrient loading could explain the resulting eutrophic conditions of the pond.
