Floodplain forests contribute to the maintenance of water quality as a result
of
various biogeochemical transformations which occur within them. In particular,
they can serve as sinks for nutrient run-off from adjacent uplands or as nutrient
transformers as water moves downstream. However, little is known about the potential
that land management activities may have for alteration of these biogeochemical
functions. This paper examines the effects of three harvesting regimes (unharvested
control, clearcut, and partial cut) on the physical and chemical parameters
within the Flint River floodplain located in southwestern Georgia, USA. Data
presented in this paper were collected during the year following initiation
of the harvesting treatments which occurred in September of 1993. Sheetflow
water chemistry (total suspended solids (TSS), total dissolved solids (TDS),
nitrate (NO<SUB>3</SUB><SUP>-</SUP>), phosphate (PO<SUB>4</SUB><SUP>3-</SUP>),
sulfate (SO<SUB>4</SUB><SUP>2-</SUP>), calcium (Ca<SUP>2+</SUP>),
potassium (K<SUP>+</SUP>),
magnesium (Mg<SUP>2+</SUP>), ammonium (NH<SUB>4</SUB><SUP>+</SUP>),
total phosphorous (P),
total nitrogen (N), total carbon (C), dissolved organic carbon (DOC)), sedimentation
rates, depth of soil oxidation after flooding, saturated hydraulic conductivity,
and bulk density were measured. During the year immediately after treatment
installation, alterations in some of the physical and chemical properties (TDS,
NO<SUB>3</SUB><SUP>-</SUP>, total P, and K<SUP>+</SUP>)
of floodwaters crossing harvest plots were detected. Soil oxidation depths,
saturated hydraulic conductivity and bulk density also changed with treatment.
The meaning of the changes detected is uncertain but they suggest the nature
of potential changes in nutrient spiralling and non-point source cumulative
effects that may occur within a managed watershed. Second-year data may offer
an interesting comparison of sheetflow chemistry and sedimentation changes between
vegetated and non-vegetated conditions.