Wilson's Creek, Greene and Christian Counties, Missouri: Water Quality Macroinvertebrate Indices, and Planning Implications Using Gis, Based on Watershed Landuse and Water Contamination Hazards

Date of Graduation

Summer 1997

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology, and Planning

Committee Chair

David Castillon

Abstract

Suburban areas of Springfield, Missouri, the location of the headwaters of Wilsons Creek are rapidly growing, as are surrounding towns in the creek's middle drainage basin. Springfield has long used the creek, a losing stream in a karst area, as the depository for wastewater treatment effluent, and has periodicaly polluted the creek due to over-capacity use by the city's largest wastewater treatment plant. Due to karst topography, contamination of groundwater aquifers is possible. This study had several objectives, the first being the 1995-1996 collection, counting, and identification of macroinvertebrates from five test sites on Wilsons Creek and one control site, along with assessment using eight indices. A formula was divided for an Average Biotic (AB) Index. Secondly, comparisons of both biological and chemical/physical water quality before the 1993 expansion of the wastewater treatment plant were completed, using two historic studies for biological comparison. Formulas were developed for two representative Chemical/Physical (C/P) Indices. Thirdly, geographic information systems (GIS) were used to map and measure areas of watershed landuse in 1984 and 1995, to use Aley and Thomson's criteria to expand their 1980 map of Greene County water contamination hazard areas to include Christian County portions of the watershed, and to combine 1995 landuse and water contamination hazard areas into a series of maps depicting land most and least suitable for development. Finally, the study sought to determine any statistical relationship between AB and C/P Indices and percentage of developed landuse in the subbasins drained by each test site. Results of macroinvertebrate indices showed slightly better water quality at the control site than at the most downstream Wilsons Creek site. Both AB and C/P indices indicated improved water quality as distance downstream increased. Comparison of historical biological studies revealed Wilsons Creek water quality below the treatment plant had decreased compared to a 1981-1982 study, but improved compared to a 1988-1989 study. In both cases, Wilsons Creek and control stream reaches not affected by effluent showed decreased water quality, possibly related to urbanization. C/P studies revealed that improved water quality seen after 1993 treatment plant expansion remained at the upstream test site after both one and three years, but improvements at lower sites were less apparent after three years, due to nutrient enrichment, indicating non-point landuse influences. Residential landuse in the watershed increased 59.2% between 1984 and 1995, and only 28.3% of the watershed was in a low hazard area for water contamination. Only 10.4% of the watershed was in a low hazard area and not already developed in 1995. A significant statistical relationship existed between landuse, AB Index and C/P Indices, with the correlation stronger between landuse and AB Index than landuse and C/P Index. Without public education concerning karst topography, non-point source reduction, and planning strategies, increased landuse-related non-point sources may offset water quality improvement resulting from the 1993 treatment plant expansion.

Subject Categories

Earth Sciences

Copyright

© Jill Alice Black

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