This video illustrates the process of drawing a groundwater flow net below a dam from a headwater reservoir on the left to a tailwater reservoir on the right. A cutoff wall protruding below the base of the dam increases the flow path length, decreasing the flow velocity, thus reducing the potential for the groundwater flow to erode the porous material at the toe of the dam. (13 minutes)
A discussion of the material in this video is provided in Section 2.6 “The “Hear See Do” of Flow Nets” of the Groundwater Project book “Graphical Construction of Groundwater Flow Nets”. Section 2.6 can be read online, or the entire book can be read online or a PDF of the book can be downloaded.
Citation: Poeter, E. (2020). Flow Paths: Sketching a Groundwater Flow Net. Video of The Groundwater Project, Guelph, Ontario, Canada.