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Abstract

The objective of this study was to assess the water quality of the Big Creek watershed during the winter and spring of 2002 by analyzing water physical, chemical variables, aquatic macro-invertebrates, and habitat. The Big Creek watershed, arising on Crowley's Ridge in northeast Arkansas, is a small deltaic watershed and is an area of intense cultivation. Four stations, Big Creek Upper (BCU), Mud Creek (MC),Lost Creek (LC), and Big Creek Lower (BCL) were established for this study from Big Creek, Mud Creek and Lost Creek. Water samples were collected on a weekly basis for 10 weeks from January 2002 through March 2002. We analyzed these streams for temperature, pH, D.O., conductivity, TSS, chlorophyll- a, DOC, total N and P, total dissolved N and P, nitrate, ammonium, and soluble reactive phosphorus. During this time period, we also sampled aquatic macroinvertebrates and assessed stream habitat according to USEPA rapid bioassessment protocols. Overall, nutrients and TSS were high, pH fluctuated from 5.8 to 7.8, and D.O. was moderate to high, ranging from 6.75 to 13.24 mg/L. Generally, physical and chemical water variables were correlated with changes in stream discharge. For a 20-jab dip-net sample, macroinvertebrate species richness ranged from 9 to 23 taxa, while abundance ranged from 38 to 209 individuals per station. Physical habitat index scores ranged from 75 to 104 (maximum of 200) indicating marginal physical habitat. We report that this watershed has high concentrations of nutrients and suspended solids during the winter and spring wet season and that the macroinvertebrate communities are influenced by stream conditions, including marginal physical habitat.

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