On 26 August 1992, the eye of Hurricane Andrew passed within 80 kilometers of a hydrologically isolated, forested wetland in southern Louisiana where we have been collecting water quality and forest productivity data since 1988. Hurricane-induced tree mortality ranged from 1.8 ± 1.2% to 8.2 ± 2.3% of all trees within the three sites in our study area. Hurricane-generated leaf flux to the swamp ranged from 30% to 41% of the normal total annual leaf litterfall. The hurricane leaf nutrient flux was equivalent to up to 45% of the normal annual nutrient flux because nitrogen and phosphorus concentrations in the hurricane-generated leaf litter were significantly higher than normal autumn leaf litter. We examined the effect of this flux on water quality (TKN, N03-N, total P, P04-P, K, Cl, Na, dissolved oxygen, and BOD5) in a section of the swamp receiving secondarily treated wastewater effluent and a similar control swamp, not affected by wastewater. From May 1992 to September 1993, the concentrations of all water quality parameters considered here, except dissolved oxygen, were significantly higher in the treatment site (P < 0.05) than in the control site because of effluent inputs. Hurricane litter had no effect on dissolved oxygen concentrations in either site because these systems are naturally dystrophic. We measured an increase in biochemical oxygen demand in the control site after the hurricane, probably because decomposition was N limited. A similar increase was not observed in the enriched site after the hurricane, and normally high N03-N concentrations were reduced, suggesting that microbial decomposers were utilizing this effluent supplied source of nitrogen. Water column concentrations of TKN, total P, and PO4-P were not affected by the influx of leaf litter; however, K concentrations increased significantly in the control site. Concentrations of Na and Cl remained at normal levels in both sites after the hurricane, indicating that no coastal water reached the site.