Okaloosa County BOCC — December 6, 2016 — Sand Trace Study - ETS OkaloosaBCC 6Dec16 v3

Sand Transport Study, East Pass, Destin, FL. Okaloosa County Board of County Commissioners Tues. 6 Dec 2016 Dr. Jon Marsh, ETS • Jon Marsh: BSc. Hons. Oceanography & Geology. PhD in sediment transport proving movement & fate of sediment in lakes, rivers, estuaries & coasts >25 years studying sediment transport. • >100 sediment transport studies worldwide: many more than anyone else • Experience/knowledge: 14 US states, 12 USACE & UK/EU, Australia & NZ - Fort Pierce Inlet, FL. (FDEP, St. Lucie County & Taylor Eng.), Pascagoula (Mobile Corps) • Specialise in sediment tracing & metocean data & measurements: critical review of past studies, evaluate modeling, identify data gaps, provide tangible & unequivocal data, provide solutions & solve real-world problems, piece together ‘jigsaw’ to complete picture… • Calibration & validation data for sediment transport models: Critical to be accurate, reflect observations & fit for purpose e.g. sediment management – public & regulators sceptical • 100% independent, neutral & no agenda • Jon Marsh: BSc. Hons. Oceanography & Geology. PhD in sediment transport proving movement & fate of sediment in lakes, rivers, estuaries & coasts >25 years studying sediment transport. • >100 sediment transport studies worldwide: many more than anyone else • Experience/knowledge: 14 US states, 12 USACE & UK/EU, Australia & NZ - Fort Pierce Inlet, FL. (FDEP, St. Lucie County & Taylor Eng.), Pascagoula (Mobile Corps) • Specialise in sediment tracing & metocean data & measurements: critical review of past studies, evaluate modelling, identify data gaps, provide tangible & unequivocal data, provide solutions & solve real-world problems, piece together ‘jigsaw’ to complete picture… • Calibration & validation data for sediment transport models: Critical to be accurate, reflect observations & fit for purpose e.g. sediment management – public & regulators sceptical • 100% independent, neutral & no agenda Why I am here today? - Lot of work, studies, modeling, measurements done in East Pass to date, but…. - Uncertainty & disagreement from lack of understanding on key processes (tidal/waves), impact of natural processes (storms) vs dredging (creating deep hollows) & borrow areas (considered minor) despite breaking longshore conveyor belt & cross-shore processes & depth of closure - Modeling as ‘good’ & as comprehensive as any other, but is flawed, inaccurate, incl. fudge factors, crude assumptions & not properly calibrated/validated & does not ‘fit’ real observations - Without certainty, understanding, accuracy – cannot manage sediment locally/regionally & ‘reacting’ - dredging, coastal erosion, nourishment projects, sand capture & transfer systems…. - Propose sand tracing study to bring all disparate info together built on real data • Fluorescent environmentally inert particles: mimic sand grains: size distribution & density • Very detectable & ideal for high energy sites: tracked >5 years & 10’s sq. miles e.g. Mouth of Columbia River, OR. - detect 1 grain in 1lb dry sand • Sediment tracers assimilate complex key 3D processes: tides, currents, waves, wind- driven circulation, bedform, burial – USACE ERDC ‘only way to measure this type of information’ • Multiple colours: label different sediments, sites, dredged material, weather conditions… • Map distribution & fate over time to determine: - transport pathways & rates - volume & mass balance - calibrate/validate numerical models - quantify size that moves & also remains… - No hope of sediment transport model predictions being correct • Current models cannot solve complex & small-scale equations of motion in 3D: (incl. Delft 3D) erosion-resuspension, settling-deposition, turbulence, bedform, burial, saltation, re- entrainment….key for nearshore beaches & inlets – author van Rijn ‘5-10 years a