Submitted to: Society of Environmental Toxicology and Chemistry Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/18/2004
Publication Date: 5/27/2004
Citation: Stephens, W.W., Moore, M.T., Farris, J.L., Bouldin, J.L., Cooper, C.M. 2004. Considerations for assessment of wadeable drainages in the agriculturally dominated deltas of Arkansas and Mississippi [abstract]. Mid-South Regional Society of Environmental Toxicology and Chemistry. p. 16. Interpretive Summary:
Technical Abstract: Historical land use changes have included the development of extensive drainage systems in the Deltas of Arkansas and Mississippi. The watershed protection approach promoted by US EPA is currently used to assess regional stream conditions and focuses on least disturbed reference conditions. The effectiveness of this regional approach may be limited by a lack of specific references for drainage ditches in the Delta. During the summer of 2001, Rapid Bioassessment Protocols (RBPs) were conducted to assess potential water resource impairments from 17 drainage ditch sites in Arkansas and Mississippi deltas with 19 fish and 105 macroinvertebrate taxa identified. Macroinvertebrate taxa richness was reduced in sites from southeast Arkansas compared to northeast Arkansas sites. While a metric for Ephemeroptera, Plecoptera, and Tricoptera (EPT) taxa could be used to indicate relative condition of these systems, macroinvertebrate assemblages were dominated by Coleopteran, Dipteran, and Hemipteran taxa at most drainage sites. The dominance of such mobile, early colonists limit applicability of some metrics for assessment of conditions that may at times be dominated more by ephemeral conditions (water quantity) and habitat (maintenance of ditches) than by degraded integrity. This study of Delta ditch conditions indicates a disparity in the usefulness of the current watershed approach in assessing the ecological integrity for this region.