Forecasting Scour Related Mine Burial Using a Parameterized Model

1. Forecasting Scour Related Mine Burial Using a Parameterized Model Carl T. Friedrichs and Arthur C. Trembanis Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, VA Approach Use NOAA WW3 model to forecast local wave height (calibrated with Wiberg) Use Whitehouse scour model (“DRAMBUIE”) to predict scour (calibrated with Elmore et al.) Post on web predicted burial since start of IRB experiment including 5-day forecast Conclusions Rapid scour occurs for increasing Ub > 1.25 Ucr Rapid burial follows when Ub drops below 0.75 Ucr Weather forecasts may introduce more uncertainty than burial model Web forecasts provide inputs (wave height, orbital velocity, wind) for other modelers Interactive web-based program provides insight into parameter sensitivity (Friedrichs, C.T., and A.C. Trembanis, 2003. Forecasting scour related mine burial using a parameterized model. ONR Mine Burial Prediction 3rd Annual Meeting, St. Petersburg, FL, 28-29 January )

2. 40 30 20 10 0 0 50 100 150 200 250 300 400 450 500 350 80 60 40 20 0 0 50 100 150 200 250 300 350 400 450 500 Sequence of Hindcast/Forecasts of Waves and Burial for Indian Rocks Beach Field Site (D = 0.47 m, d = 0.19 mm, fw = 0.008, h =12 m, Tw = 7 s, Ub = 0.28 Hs w/[sinh(kh)] 2.5 2 Significant Wave Height (meters) 1.5 1 0.5 0 Noon EST Tues Jan 28 = Hour 485 0 50 100 150 200 250 300 350 400 450 500 1.25 Ucr RMS Wave Orbital Velocity (cm/s) 0.75 Ucr Rapid scour occurs for increasing Ub > 1.25 Ucr Rapid burial follows when Ub drops below 0.75 Ucr Mine Burial (percent) Bmin = 0.1 Hours Since January 8 2003 12:00 zulu Thin colored lines = hindcasts/forecasts updated every 12 hrs o = Latest available hindcast/forecast as of hour 384

3. 40 30 20 10 0 0 50 100 150 200 250 300 400 450 500 350 80 60 40 20 0 0 50 100 150 200 250 300 350 400 450 500 Sequence of Hindcast/Forecasts of Waves and Burial for Indian Rocks Beach Field Site (D = 0.47 m, d = 0.19 mm, fw = 0.008, h =12 m, Tw = 7 s, Ub = 0.28 Hs w/[sinh(kh)] 2.5 2 Significant Wave Height (meters) 1.5 1 0.5 0 0 50 100 150 200 250 300 350 400 450 500 Revised forecasts of wave height lead to drastic changes in forecast burial RMS Wave Orbital Velocity (cm/s) Weather forecasts may introduce more uncertainty than burial model(!) Mine Burial (percent) Bmin = 0.1 Hours Since January 8 2003 12:00 zulu Thin colored lines = hindcasts/forecasts updated every 12 hrs o = Latest available hindcast/forecast as of hour 384

4. Interactive Mine Burial Model Using WW3 Forecasts for IRB Field Site Accessible via www.vims.edu/~cfried/MBP