Stream Classification for TMDL Assessment Using a Dimensionless, Reference Reach ApproachEPA Grant Number: R831366
Title: Stream Classification for TMDL Assessment Using a Dimensionless, Reference Reach Approach
Investigators: Wilson, Bruce , Nieber, John L. , Perry, James A. , Vondracek, Bruce
Institution: University of Minnesota - Twin Cities
EPA Project Officer: Goodman, Iris
Project Period: November 10, 2003 through November 9, 2006
Project Amount: $769,592
RFA: Development of Watershed Classification Systems for Diagnosis of Biological Impairment in Watersheds (2002) RFA Text | Recipients Lists
Research Category: Water and Watersheds , Water
The overall goal of the proposed project is to develop a simple classification system that is useful in TMDL assessment. Research objectives are: (1) to investigate the relationship between indicators of stream health and localized stream characteristics, (2) to develop and evaluate dimensionless curves using reference reach values as a tool for stream classification and TMDL assessment, and (3) to propose and test a stream classification system using the prediction intervals of the dimensionless curves. Three parallel hypotheses will be evaluated to complete the project.
The classification method uses regional reference reaches to account for complex factors related to precipitation, land use, soil and geology. Dependent variables of stream health and independent variables of localized stream characteristics are converted into dimensionless form by normalizing their values by those of the reference reach. Dimensionless relationships are obtained using regression analyses. The variance of predicted values are used to compute three different prediction intervals. These intervals are then used to classify streams within a given region. Development and evaluation of the proposed classification system will be done using a large data set of stream stations gathered within four considerably different regions in Minnesota. An independent data set will be used for testing.
The classification system will be used by states to prioritize efforts related to TMDL programs. The approach is well suited for considerations of changes in land use and other watershed practices.