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ASSOCIATIONS BETWEEN MEASURES OF BEDDED SEDIMENTS AND STREAM LIFE
Citation:
Cormier, S M., S. Niemela, AND J. Chirhart. ASSOCIATIONS BETWEEN MEASURES OF BEDDED SEDIMENTS AND STREAM LIFE. Presented at Society of Environmental Toxicology & Chemistry, Portland, OR, November 14-18, 2004.
Impact/Purpose:
The purpose of this research project is to provide methods, tools and guidance to Regions, States and Tribes to support the TMDL program. This research will investigate new measurement methods and models to link stressors to biological responses and will use existing data and knowledge to develop strategies to determine the causes of biological impairment in rivers and streams. Research will be performed across multiple spatial scales, site, subwatershed, watershed, basin, ecoregion and regional/state.
Description:
Associations between causal agents and biological effects are necessary for the development of water quality criteria and, when combined with information from a site, can provide evidence for causal analysis. These associations can be obtained from controlled laboratory studies or from observational studies of natural systems. Quantile regression, regression using various binning procedures, and maximally observed biological performance conditional on stressor levels are among some of the approaches to quantify and illustrate effects observed in natural systems. These three methods were compared using data obtained by the Minnesota Pollution Control Agency in the St. Croix River Basin during 1996-2003. Fish and invertebrate metrics were analyzed along with measures of percent embeddedness, percent fines and depth of fines. Invertebrate metrics and percent fines were more sensitive measures of effects and exposure, than fish and percent embeddedness or depth of fines. This initial study did not evaluate organic matter, resolution of particle size below 1mm, stream gradient or other factors than may contribute to overall effects, and yet useful associations were identified that states and tribes might use to set criteria for regulation of excess sediment in streams and for TMDL cases where sediment is a candidate cause of biological impairment.