Abstract

Benthic macroinvertebrate communities of Huntington River, Emery County, Utah were studied to determine effects of sedimentation from construction of Electric Lake Dam, a state highway, and two bridges. Approximately 900 benthic samples were collected from riffle areas above, in, and below the construction zone from January, 1971 to December, 1973. Two settling basins below construction sites were effective in limiting scouring of downstream communities. Heavy silt deposition was limited to a 1-km stream reach. Number of indicators, density, and biomass were reduced in the construction zone during periods of sediment input. During periods of scouring, density and biomass were reduced; however, community diversity (d̅) increased due to a reduction of the more populous taxa. The mean d̅ value in the construction zone was 2.05 compared to 2.81 outside. Ordination analysis revealed dissimilarity in communities in, above, and below the construction zone. Specific indicators showed varying response to sedimentation. Recovery was rapid following scouring but slow following sedimentation.

Degree

College and Department

Life Sciences; Plant and Wildlife Sciences

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