Transmission Structures Exposed to Water Flow: Resiliency and Risk Mitigation

The forces associated with flooded rivers can be incredibly destructive, causing significant damage to widespread areas. Urbanization, tiling of agricultural land, and an increasing trend in heavy precipitation are some of the suspected contributors to more frequent large-scale flooding of river basins across the United States. With this increasing commonality of flooding, a growing number of transmission structures are being put at risk. Fast flowing water carrying pieces of debris or ice can potentially damage or destroy structures within its path. Many existing transmission poles within new or changing flood zones are not robust enough to stand up to these forces. The damage can lead to costly repairs and lengthy outages because of the difficulties that accompany traversing and constructing in the flooded terrain. This paper is a case study of a structure failure along the Minnesota River. It includes an investigation into the factors that contributed to the structure failure and takes a detailed look at the difficulties associated with post-failure reconstruction. By comparing the flow data collected on the Minnesota River Basin over the past century to land use and precipitation trends, this paper draws some conclusions as to why such noticeable changes have occurred in the basin and explores the impacts those changes have had on transmission infrastructure.