Down to the bottom of his budget, Bret Webb built his own sediment sampler from PVC plumbing parts. MISSION: WATER 10 HEADLINE SURFACE WATER JagSki Challenge When his team had completed what it could accomplish on foot, it was time for Webb to launch his JagSki, a Kawasaki Ultra LX personal watercraft outfitted with a SonTek HydroSurveyor/RiverSurveyor-M9 Acoustic Doppler Profiler (ADP) and YSI Portable SeaKeeper multiparameter sampling system. With a top speed of 40 knots and the ability to run in just a few inches of water, Webb figured the maneuverable JagSki would make quick work of mapping the lake bed. Getting the JagSki into the lake ended up being a bigger challenge than expected. Webb attempted backing down a footpath to the lake, but the path’s angle was too steep, and Webb ended up cramming the impeller and water intake full of mud and vegetation, disabling the JagSki. Recovering the craft from the lake, he also damaged his trailer and hitch. Webb realized he needed a more nimble approach. Resourceful Like the hero of the television series MacGyver, Webb is a master of cobbling together clever fixes with the tools close at hand. Instead of working with paper clips and chewing gum, Webb specializes in PVC and electronics. After all, he had already built a JagSki. He just needed to find a suitably lighter platform. Inspired by literature he had read about kayak-based surveying, Webb committed part of his grant money to purchasing a kayak. Then he went to a home improvement store to stock up on parts to mount the M9 to the hull. He dubbed his creation the JagYak in honor of University of South Alabama’s mascot, the Jaguars. The concept was simple, he says, but confesses that making the first cut was tough. “You go to the store not anticipating spending $600 on a kayak, then the first thing you do when you go home is cut a 5-inch hole in the bottom. There’s a little trepidation there,” Webb laughs. After cutting a length of 5-inch (12.7-cm) PVC pipe to act as a sleeve for the M9, Webb fashioned a collar that could fasten on either side of the kayak’s hull to create a waterproof seal around the instrument. Originally, he also constructed a waterproof enclosure for his laptop in hopes that he could reference the M9’s HydroSurveyor software as he paddled, but the computer kept overheating during testing. “It’s probably not smart to take a computer on a kayak anyhow, so this was likely a blessing in disguise,” Webb concluded. Onboard Capabilities Instead of running the system through his laptop on the water, Webb utilized the dual-function capability of the M9, switching from its HydroSurveyor mode—which would have enabled him to navigate with a display of his line plan on his laptop screen and view his measurements in real-time—to its RiverSurveyor function. The switch allowed instrument- based datalogging of depth and velocity readings that Webb processed afterwards on his laptop, which was left safely in his truck during his survey forays to the lake. Isaac Jones, product manager at SonTek, notes that the M9 offers users the choice between RiverSurveyor or HydroSurveyor mode. “RiverSurveyor and HydroSurveyor modes are different firmware packages for the M9 hardware, allowing users to optimize the system for their needs,” Jones explains. “RiverSurveyor firmware optimizes the M9 to emphasize velocity measurements and calculate discharge." HydroSurveyor mode is optimized for depth measurement, with less emphasis on velocity, and displays real-time and historical data on a map. That makes HydroSurveyor mode better suited for bathymetry. Users specify the package they want when they purchase an M9, and can unlock the other mode if their needs change—for instance, if they need to switch from river measurements to lake bathymetry surveys. Webb’s JagYak offered mobility, shallow- water access, and a highly maneuverable platform for his SonTek M9 acoustic Doppler profiler and home-made sediment sampler. Photos: Dr. Bret Webb