Nearshore Dredged Material Placement Pilot Study at Noyo Harbor, CA

Transcription

1 1 Nearshore Dredged Material Placement Pilot Study at Noyo Harbor, CA Noyo Cove N 2011 National Conference on Beach Preservation Technology 9-11, February 2011 Lihwa Lin, Honghai Li, Mitchell Brown US Army Engineer Research and Development Center Frank Wu, Lisa Andes US Army Corps of Engineers, San Francisco District

2 2 2 Noyo Harbor, CA It is a small port in the north-central CA coast ~150 mile NW of the San Francisco and 160 mile SSE of Crescent City The Harbor services commercial and sport fishing, as well as a US Coast Guard (USCG) Search and Rescue Station between Bodega Bay and Humboldt Bay The Harbor is located inside the Ten Mile River Cell encompassing the Mendocino County shoreline as one of ~ two dozen littoral cells along the CA coast Construction of harbor jetties, and10-ft deep, 100-ft wide entrance channel completed in 1961

3 3 3 Noyo Harbor Project Background Federal Channel first dredged in the 1930s : Channel dredged ~ every 1 to 2 years, material placed in upland site (~ 20k to 30k cy/yr) Ocean Disposal site (OD0939) offshore Noyo Cove expires in 1997 Ten Mile River : Channel dredged ~ every 5 to 7 years (most recent dredging completed in October 2009) 2006: Emergency dredging of the Federal Channel after USCG must sit out storms in Noyo Cove to perform their mission Upland site is filled to maximum capacity

4 Objectives Use numerical models to estimate the sediment transport rate at potential nearshore site for dredged material Evaluate beneficial use of dredged material at the nearshore placement site Model sedimentation processes of releasing dredged material in the placement site Assess changes by the dredge material placement to the nearshore environment Technology transfer for regional sediment management project application Coastal Inlets Research Program 4 4

5 5 5 Method Assemble and review relevant historical data on bathymetry, tide, waves, wind, and sediment Run Coastal Modeling System (CMS) for a summer month and a winter month Drive the CMS with wind, waves, and water level elevation data for pre- and postplacement of the dredged material Analyze and compare model simulation results under the existing condition and two different placement locations

6 6 Coastal Modeling System (CMS) Developed since main models: CMS-Flow CMS-Wave CMS-PTM Physics-based to simulate complete coastal processes Integrated and user-friendly system in SMS

7 7 Assemble Bathy and Topography Data GEODAS LIDAR CSMP DEM

8 8 CMS Grid Bathymetry and Domain Grid 747 x 273 cells (~120k computational) Avg. depth on offshore edge ~313m Ten Mile River 35 mile Noyo Harbor Potential placement site 11 mile Grid resolution: Min: 20m x 20m In project area Max: 200m x 200m In other areas

9 9 Wind and Wave Climates Wave Height (m) Wind (m/s) Buoy NORTH Noyo Bay 5% 10% WEST 0% EAST H s (m) SOUTH >= H mean ~ 2 m Θ mean ~ NW (296 o ) Wind mean ~ 5-10 m/s Θ mean ~ N (360 o )

10 10 Tides and Month Mean Waves NOAA ( Humboldt Bay North Spit) and (Arena Cove, ANVC1)

11 11 Sediment Characteristics NH (most seaward reach) NH (center reach) NH (most inland reach) Sample Mean Coarse Grain Fractions (%) Gravel Sand TOTAL Fine Grain Fractions (%) Silt Clay TOTAL (Weston Solutions, 2009)

12 12 Potential Placement Site 1 and 2 for CMS Simulation 3 mile Parameter Value Manning s n Advection Included Wetting and Drying Included (minimum wet depth is 0.1 m) Wave Spectral Energy Half Plane Wave Breaking Extended Goda formula (Goda 1973) Diffraction Intensity 4.0 D 50 (mm) 0.18 Sediment Density (kg/m 3 ) 2,650.0 Sediment Porosity 0.4 Hard Bottom Partial (0 to 40-ft depth), with an initial 4-inch thick sediment layer Transport Equation Non-equilibrium 2 mile Potential site (1 or 2) for the placement of 46k cy (35k cubic m) dredged material, each site ~ 700 x 3,700 (210m x 1,120m) between 40 and 60 (12 and 18 m) depth

13 13 Wind and Wave Condition August 2008 and January 2009

14 14 Water Level Information August 2008 and January 2009

15 15 Max Sediment Concentration for Dredged Material Placement at Site 1 without Wave Forcing August 2008 January 2009

16 16 Max Sediment Concentration for Dredged Material Placement at Site 2 without Wave Forcing August 2008 January 2009

17 17 Max Sediment Concentration for Dredged Material Placement at Sites 1 & 2 with Wave Forcing August 2008 January 2009

18 18 Sediment Accretion/Erosion for Dredged Material Placement at Site 1 without Wave Forcing August 2008 January 2009

19 19 Sediment Accretion/Erosion for Dredged Material Placement at Site 2 without Wave Forcing August 2008 January 2009

20 20 Sediment Accretion/Erosion for Dredged Material Placement at Sites 1 & 2 with Wave Forcing August 2008 January 2009

21 21 Evaluation of Dredged Material Placement at Site 1 & 2 Placement Site August 2008 Calculated Morphology Change (cy)* Area A Area B None 60,830 16,400 Site 1 59,850 (-1.6%) 16,280 (-0.7%) Site 2 59,700 (-1.8%) 16,250 (-0.9%) * Percent difference in parentheses is compared to the existing configuration Placement Site January 2009 Calculated Morphology Change (cy)* Area A Area B None -186, ,930 Site 1-186,490 (-0.04%) -157,860 (-0.05%) Site 2-186,620 (0.03%) -157,980 (0.03%) * Percent difference in parentheses is compared to the existing configuration

22 22 Unload Clay Particles, August 2008 CMS-PTM Simulation Day 12 Clay Particles released twice a day in the first 12 days, each release ~ 100 cy Day 30

23 23 Unload Silt Particles, August 2008 CMS-PTM Simulation Day 12 Silt Particles released twice a day in the first 12 days, each release ~ 150 cy Day 30

24 24 Release Clay Particle Animation August 2008

25 25 Summary The CMS is applied in the Noyo Harbor Pilot Study to simulate the sediment transport at two potential nearshore placement site of the dredged material from Noyo Bay channel and Noyo River The model result shows overall coastal erosion in the winter month and sediment accretion in the summer month Coastal processes are more dominated by wave breakings along the shoreline than tide and wind-driven currents The model simulation shows that the placement of dredged material at Site 1 and 2 has small influence to the ambient sedimentation processes (less than 2% total volume change as compared to the pre-placement condition)

26 THANK YOU Questions? Barge Capacity - Maximum Volume: 2000 cy - Actual Volume: 1800 cy (90%) - Sediment Volume: 1440 cy (80%)