Date of Submission


Document Type


Degree Name

Master of Science in Environmental Science


Biology and Environmental Sciences


Roman Zajac


Dam retirement


Dam removal is being increasingly used nationwide to restore impaired rivers and streams. While dam removals are becoming more prevalent, little is known about whether these efforts create conditions for the enhancement and or establishment of desired biota.

Ongoing monitoring of these projects is an important step in the restoration process to ensure project goals are being met and the restoration has been successful.

This thesis focuses on the Pond Lily Dam removal and restoration which took place in October 2015 along the West River in New Haven Connecticut that removed an aging mill dam with the objective of restoring the impoundment area back to a more natural habitat. Macrobenthic invertebrates were collected at the restoration site to perform an ecological assessment of the efficacy of the restoration in comparison to theexisting Konolds Pond dam and impoundment as a control. Using multivariate analysis, community structure was analyzed to track the response of the benthic community at the Pond Lily Dam site and understand if the restoration had a positive impact on the ecosystem during the year following restoration. Based on the community composition, and diversity, the Pond Lily Dam ecosystem responded positively to restoration the year following removal of the dam.

However, community composition was still highly variable and no apparent climax community had been reached. Based on this research, it is suggested that monitoring continue to better understand how benthic communities respond to major restoration efforts and to ensure the Pond Lily Dam site continues to improve and provide high quality habitat for native species.