Stream water quality changes following timber harvest in a coastal plain swamp forest

The Goshen Swamp, a fourth order blackwater creek in southeastern North Car olina, was clearcut of 130 acres of riparian and seasonally flooded forest in late May through September 1998. Downstream water quality had been monit ored monthly for 21/2 years before the clearcut, during the clearcut, and f or two years following the clearcut. The objective of this paper was to tes t the hypothesis that clearcutting in the Goshen Swamp watershed negatively impacted downstream water quality. To do so, data from the Goshen Swamp we re compared with data collected from a neighboring control creek (Six Runs Creek) of similar size, land use, and hydrologic characteristics. Compared with the control creek, the post-clearcut Goshen Swamp displayed significan tly higher suspended solids, total nitrogen, total phosphorus, total Kjelda hl nitrogen and fecal coliform bacteria, and significantly lower dissolved oxygen over a 15 month period, Longer-term deleterious effects included rec urrent nuisance algal blooms that had not been present during the 21/2 year s before the clearcut. Although a 10 m uncut buffer zone was left streamsid e, this was insufficient to prevent the above impacts to stream water quali ty. (C) 2001 Elsevier Science Ltd. All rights reserved.