Boardman River Feasibility Study – A Plan for the Drawdown of Boardman Pond - Working Draft

Abstract

As part of the study of the proposed drawdown of the Boardman (Keystone) Pond impoundment we investigated the influence that the proposed drawdown will have on the stability of the slopes and structures adjacent to the impoundment. In order to identify locations of potential instability we became familiar with the site by making onsite observations and studying the geological and topographical information available. For this portion of the study we were particularly interested in the types of soil materials present within the region, the pitch of the slopes that are currently exposed adjacent to the impoundment, the pitch of the slopes that will be exposed after the drawdown, the ground water flow, and the location of structures and their proximity to the impoundment. Below we discuss our understanding of the site characteristics, our expectations for how the proposed drawdown may affect the slopes and structures, the associated assumptions, concerns and subsequent recommendations. Recommendations regarding monitoring of structures and slopes are included in Chapter 4.0.