Evaluation of Dam Decommissioning in an Ice-Affected River: Case Study
Abstract
Many dams across the United States are being decommissioned as a result of structural deficiencies or a desire to restore fish passage and to restore the natural stream. On northern rivers, darn removal affects the river ice processes and can result in increased ice jams and ice jams-related flooding. An analysis of the river system prior to darn removal is often necessary to ensure that increased ice jams, flooding, and damages do not result. This case study presents the types of analyses needed to investigate the ice impacts of the potential removal of the Merrimack, Village Darn on the Souhegan River in Merrimack,, New Hampshire. Of particular interest were the potential impacts to the historic Chamberlain Bridge. A HEC-RAS hydraulic model was used to estimate the ice jam thickness and resulting water surface profiles with and without an ice jam in place for both the pre- and post-darn-removal conditions. The results of this analysis indicate that removing the Merrimack Village Darn will not pose significant risk to the Chamberlain Bridge or to the area downstream.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2007
- Accession Number
- ADA475557
Entities
People
- Carrie M. Vuyovich
- Kathleen D. White