For historical water quality and meteorological data from the Lake Mead monitoring platforms, please visit: nevada.usgs.gov/lmqw/index.htm The M9’s HydroSurveyor mode allows users to track their survey patterns on an onscreen map in real time. Without his laptop, Webb counted his paddle strokes and navigated by compass to maintain his pattern. Data: Dr. Bret Webb Webb’s creativity extends well beyond clever workshop projects. To chart changes in lake bottom elevations, he manipulated a 1958 survey map to exactly fit a 2016 USGS quadrangle map. Data: Dr. Bret Webb MISSION: WATER 12 HEADLINE SURFACE WATER Massive Buildup Webb’s study of the lake bottom indicated that more than 313,000 cubic yards of sediment have collected in Lake Forest since 1958, an accumulation of approximately 16,200 tons per year. Depth has been reduced by 5 to 10 feet in most of the lake, and pool volume has been reduced by 55 percent since development began—from 356 acre- feet in 1958 to less than 197 acre-feet in 2016. The lake has experienced significant sediment buildup on more than 78 percent of its area; shoals of five feet or more have built up on more than 19 acres of the lake bottom. At the same time, significant erosion has occurred in front of the dam, leaving deep pools that are susceptible to low dissolved oxygen levels. If that hypoxic water is drawn to the upper levels of the water column by wind or surface cooling, it could be released into the spillway and discharged into Mobile Bay, Webb notes. Quantifying the massive buildup of sediment in Lake Forest was an important step in helping decision makers understand the lakes potential role in capturing floodwater and its expected reserve of sediment storage. Through his survey, Webb determined that the lake had enough capacity to capture sediment for the next 90 years at the rate it has been flowing since it was built. Quantifying the amount of sediment already in the lake also helped him estimate the staggering cost of dredging and sediment relocation. With Bret Webb’s detailed maps in hand, decision makers will have a great tool for planning the future of Lake Forest—made possible by a scientist with a creative mind and a talent for improvisation. Attracting Alligator Attention Mapping Alabama’s Lake Forest in a modified kayak provided University of South Alabama’s Bret Webb with a detailed bathymetric survey. It also provided a few thrills. “I have never before worked in an area with so many active alligators,” Webb says. “They were very curious the entire time we were working, especially the little baby alligators. So every time I attracted the attention of a baby alligator, I was quickly looking around to find out where big momma was!” southce.org/bwebb bwebb@southalabama.edu @dr_bw