BTNEP Management Conference August 7 th, 2014 Atchafalaya Long Distance Sediment Pipeline Feasibility Study Identification of Borrow Sites Maarten Kluijver
Land Loss Central Terrebonne Parish
Project Region and Study Area Part 1: Where would one find suitable sediments for marsh restoration Atchafalaya Bar Channel Atchafalaya Bay MORGAN CITY Flat Lake Bayou Boeuf Avoca Island Bateman Island Bayou Shaffer Project Region and Study Area Approximate Point of Intake Atchafalaya LDSP Borrow Site Identification Study Area Pipeline Corridor Land Loss 1932-2010 (Source: USGS) Lake Palourde Bayou Penchant Fourleague Bay Bayou Chene Carencro Lake Lost Lake USACE Dredge Reaches Bar Channel Bay Channel Horseshoe Bend Bayou Chene Tennessee Gas Pipeline Corridor Lake Cocodrie Lake Hackberry Columbia Gas Pipeline Corridor Goose Bay Lake Mechant Mud Lake Caillou Lake Hackberry Lake Lake Hatch HOUMA Lake De Lake Boudreaux Lake Gero one transport the sediments Cade Bay Jug Lake Long Lake for Raccourci marsh Bay restoration Quitman Lake Pagie Lake Theriot Part 2: Lake Penchant How and to what locationswould Bayou Boeuf Bayou Black Sweetwater Pond Miles Madison Bay Te rre bon ne Bay Ü Wonder Lake Lake Ta mb our Lake Barre 0 3 6 12 18
Feasibility Study Part 1 Chapter 1 1. Beneficial Use Material Sediment dredged from maintenance dredging in the Lower Atchafalaya 2. Dedicated dredging Dedicated borrow sites to serve as sediment sources for the Atchafalaya River LDSP.
CITY AMELIA Fourleague Bay Bayou Black Atchafalaya Bay Bayou Boeuf Chene Bayo u Beneficial Use of Dredge Material Hor seshoe Bend Bay Channel Bar Channel
Map ID Name 1 T Pat Island 2 Avoca 2 3 Avoca 5 4 Avoca 5A 5 Avoca 6 6 Avoca 6A 7 Avoca 6B 8 Avocet Island 9 Bayou Chene 1 10 Bayou Chene 3 11 Bayou Chene G 12 Bird Island East 13 Bird Island West 14 Black Bayou 1 15 Black Bayou 2 16 Brown Pelican Island 17 Donna Island 18 Fern Island 19 Horseshoe/Crewboat Cut A 20 Horseshoe/Crewboat Cut B 21 Horseshoe/Crewboat Cut I 22 Ibis Island 23 Kite Island 24 Ocean Dredge Material 25 Osprey Island 26 Oyster Catcher Island 27 Plover Island 28 Sandpiper Island 29 Skimmer Island 24 22 18 17 8 29 1 26 13 23 12 28 25 16 27 2 M 19 21 ile 20 Radius 5 Mile Radius 11 10 Mile Radius 10 20 Mile Radius 2 3 6 7 5 4 15 9 14 Beneficial Use of Dredge Material 30 Mile Radius
Feasibility of Dedicated Dredging Goal: To find suitable material for marsh restoration Conditions: Within the Lower Atchafalaya River Region Borrow material to transport it by pipeline Pump out location is located in the vicinity of Crew Boat Cut
Borrow Sites for Dedicated Dredging 10 7 Map ID Name Vol [MCYD] 1 BYCH 04 1.48 2 BYCH 06 3.62 3 BYCH 09 17.36 4 BYCH 11 3.13 5 BYCH 13 7.29 6 BYCH 15 1.54 7 BYSH 03 1.14 8 BYSH 06 4.61 9 BYSH 08 2.04 10 ATCH 126W 1.37 11 ATCH 128E 4.34 12 ATCH 130E 1.91 13 ATCH 130W 0.83 14 ATCH 131E 1.66 15 ATCH 131W 11.99 16 ATCH 132E 15.42 17 ATCH 132W 3.59 18 ATCH 136W 9.80 19 ATCH 137E 19.60 20 ATCH 138E 6.18 21 ATCH 139W 12.04 22 ATCH 140E 31.24 23 ATCH 141W 2.08 24 ATCH 142E 15.09 25 ATCH 143E 8.80 26 ATCH 148W 27 ATCH 149E 28 ATCH 153E 29 ATCH 153W 30 ATCH 156E 31 ATCH 156W 32 ATCH 160E 32 31 30 29 28 26 27 2 M 20 23 24 25 18 19 21 ile 22 11 13 12 14 15 16 17 Radius 5 Mile Radius 10 Mile Radius 6 20 Mile Radius 54.47 75.62 78.25 84.68 104.26 104.04 129.48 9 5 4 8 3 2 1 30 Mile Radius
Borrow Sites for Dedicated Dredging 11 8 2 Map ID Name Vol [MCYD] 1 BYCH 04 1.48 2 BYCH 06 3.62 3 BYCH 09 17.36 4 BYCH 11 3.13 5 BYCH 13 7.29 6 BYCH 15 1.54 7 BYSH 03 1.14 8 BYSH 06 4.61 9 BYSH 08 2.04 10 ATCH 126W 1.37 11 ATCH 128E 4.34 12 ATCH 130E 1.91 13 ATCH 130W 0.83 14 ATCH 131E 1.66 15 ATCH 131W 11.99 16 ATCH 132E 15.42 17 ATCH 132W 3.59 18 ATCH 136W 9.80 19 ATCH 137E 19.60 20 ATCH 138E 6.18 21 ATCH 139W 12.04 22 ATCH 140E 31.24 23 ATCH 141W 2.08 24 ATCH 142E 15.09 25 ATCH 143E 8.80 26 ATCH 148W 27 ATCH 149E 28 ATCH 153E 29 ATCH 153W 30 ATCH 156E 31 ATCH 156W 32 ATCH 160E 24 23 18 19 22 21 20 2 Mile Radius 5 Mile Radius 13 12 54.47 75.62 78.25 84.68 104.26 104.04 129.48 15 14 16 17 6 4 5 9 3
Borrow Sites for Dedicated Dredging Grab Sample A185 Grab Sample A184 Borrow Site WEST AR 136! Grab Sample A190 Grab Sample A191 Grab Sample A192 AR 137! Grab Sample A189 Grab Sample A193 REWBOAT CUT I HORSESHOE/CREWBOAT Grab Sample A194 ATCH-136W Grab Sample A188 ATCH-137E Grab Sample A195 AR 138! Grab Sample A196 Grab Sample A198 Grab Sample A199 Grab Sample A200 AR 135! Grab Sample A197 Grab Sample A186 Approximate Point of Intake Borrow Site EAST AR 134 CUT B HORSESHOE/CREWBOAT! CH 17! BAYOU CH EN E 3 CH 16 Tennessee Gas Pipeline Corridor Columbia Gas Pipeline Corridor!
Preliminary Identified Borrow Sites Borrow Site Name Quantitative characteristics Volume [Million CY] Qualitative characteristics Reach Proximity Refill Rate WEST 9.50 Horseshoe Bend Good < 2miles? CY / year EAST 19.50 Crew Boat Cut Good < 2miles? CY / year
Feasibility Study Part 1: Chapter 2 The demand of sediment for restoration projects: Volume of sediment (~50 Million CY) Time scale and sequencing of needed sediment supply (~5 Million CY per year) Chapter 2 Perform hydrodynamic and morphological modeling for the river reach that contains the 2 borrow site locations and estimate refill rates
Modeling Approach Model Setup and Development Sediment Transport Model Testing and Verification Production Runs for Water Years Result Analysis and refill rate assessment
h t 7 OL G H U A NIC P & E N T T T B FA F O Ü M _ ^ Horseshoe Bend and Crewboat Cut Model Source: Extents Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community ^ Approximate Point of Intake _ Model Grid
Numerical Model Bathymetry (Existing Conditions) ^_ Depths (m) Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community 20 19.0 18.0 17.0 16.0 15.0 14.0 13.0 12.0 11.0 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 <0
Yearly Hydrograph Discharge (cfs) Thousands 280 260 240 220 200 180 160 140 120 100 80 60 40 20 0 Yearly Average Flow - Lower Atchafalaya River at Morgan City Mean - STD Mean Mean + STD Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Yearly Average Flow - Lower Atchafalaya River at Morgan City
Model Validation Three water years were simulated Water year 2008, 2009 and 2010 Simulated vs. for Observed Sediment loads Sediment load was compared to literature Both mud, sand and total sediment load Comparison of Bathymetric Change for 2 timeframes
Simulated vs. for obs. sediment loads (1)
Simulated vs. for obs. sediment loads (2) Water Year Allison et al. (2012) Total load at Morgan City (10 6 Tons) Allison et al. (2012) Sand load at Morgan City (10 6 Tons) ST model Total Load into Horseshoe Bend (10 6 Tons) ST model Sand Load into Horseshoe Bend (10 6 Tons) WY 2008 30.9 7.3 29.4 10.1 WY 2009 22.7 3.8 23.8 6.7 WY 2010 30.1 5.0 30.0 7.7
Simulated vs. for obs. sediment loads (3)
EAST Model Bathymetry H 21.5 21 20 19 18 17 ^_ Approximate Point of Intake Ü ^_ 6 5 4 3 2 1 <0 Miles Source: Esri, DigitalGlobe, GeoEye, i-cubed, USDA, USGS, AEX, Getmapping, 0 Aerogrid, 0.5IGN, IGP, swisstopo, 1 and the GIS User 2 Community 3 16 15 14 13 12 11 10 9 8 7
Model Results for EAST Water Year Total Load Sand Load Volume of Infill [Million CY] 2006 10.85 1.38 2.23 2007 18.91 3.35 3.73 2008 29.4 10.07 8.23 2009 23.82 6.74 5.89 2010 29.97 7.73 6.64 2011 27.51 11.97 9.88
Synthesized Water Years
Calculated Infill Volumes borrow site EAST 5.6
ALDSP - Sediment Availability Borrow Site Reach Initial Volume [Million CY] Mean Annual Infill Volume [Million CY] Project Duration [Years] Average Fast Slow WEST Horseshoe Bend 9.8 3.2 14.5 12 20 EAST Crew Boat Cut 19.5 5.6 6.5 6 8
ALDSP Borrow Site Utilization The demand of sediment: Volume of sediment (~50 Million CY) Time scale and sequencing of needed sediment supply (~5 Million CY per year) Utilization Initial volume dredged in first year Let site fill in over the course of one water year Annual dredging to borrow material and keep site at the designed dimensions
Utilization of Borrow Site EAST
ALDSP - Sediment Availability Borrow Site Reach Initial Volume [Million CY] Mean Annual Infill Volume [Million CY] Project Duration [Years] Average Fast Slow WEST Horseshoe Bend 9.8 3.2 14.5 12 20 EAST Crew Boat Cut 19.5 5.6 6.5 6 8
Conclusions - Feasibility Study Part 1 Borrow site EAST can meet the project demand and is recommended for selection. Initial volume of 19.5 Million CY; Annual average infill volume of 5.6 Million CY - this exceeds the need of 5 Million cubic yards per year; The project duration is estimated to be ~6.5 years for a total demand of 50 Million CY.
Recommendations Optimization of borrow site geometry Better capture high sediment loads Gradual infilling Less impacts on currents and flow field Less impacts on currents and vessel traffic Downstream geometry and gradients in velocity
Questions