EVALUATING THE PERFORMANCE OF THE 21ST AVENUE WEST FRESHWATER ESTUARY RESTORATION IN DULUTH HARBOR: CASE STUDY I
This thesis focuses on 21st Avenue West Habitat Restoration in Duluth Harbor (Lake Superior), Minnesota as a case study where initial environmental sampling conducted in 2010 indicated impairment of overall aquatic health based on biological indicators, in particular degradation of benthos. Over 750,000 cubic yards of beneficial use of dredge material was place within established construction footprints to cap mildly contaminated sediments. A scaled trimetric index (s-TMI), scored between 0 to 1, was used to represent the benthic community, where an increasing score is indicative to improving benthic condition. Median s-TMI values for 21st Avenue responded with a positive trend towards recovery, and depending on defining reference, met the quantifiable Beneficial Use Impairment removal target for reference conditions.