Video of scuba divers exploring the deepest part (over 400 feet, ~122 m, below land surface) of the saturated zone karst conduit network of the Weeki Wachee and Twin Dees springs network near Spring Hill, Florida within the Floridan aquifer system on March 23, 2019. There are huge conduit features as well as extensive and large bedding plane voids. Under laminar flow, large volumes of water move through these aquifers. Near the end of the video the bubbles from the scuba divers gently rise indicating flow is laminar. Almost all scuba diving to map these submerged conduit systems occurs during laminar flow conditions. Average and low flow is laminar most of the time in the large, first‑magnitude springs and becomes turbulent during storm events. (4 minutes)
A discussion of the material in this video is provided in Section 4.4 ‘Fluid Mechanics of Pipes and Open Channels’ of the Groundwater Project book ‘Introduction to Karst Aquifers’, the PDF can be downloaded or the online version can be read at that link.
Citation: Pitkin, A. (2019). Karst: Laminar flow in large karst conduits. Video of The Groundwater Project, Guelph, Ontario, Canada.