COASTAL TX PROTECTION AND RESTORATION FEASIBILITY STUDY
Texas Association of Environmental Professionals Study Update
Jeff Pinsky, Coastal Biologist - RPEC Dianna Ramirez US Army Corps of Engineers Regional Manager Upper Coast Field Office, Galveston District Coastal Resources, Texas General Land Office
01/16/2020
“The views, opinions and findings contained in this report are those of the authors(s) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by other official documentation.” http://CoastalStudy.Texas.gov US Army Corps Of Engineers® STUDY SUMMARY CoastalTXStudy
Study Name: Coastal Texas Protection & Restoration Feasibility Study
Authorization: Sec. 4091, Water Resources Development Act (WRDA) of 2007 Public Law 110-114
Appropriation: 2014-2019 yr increments thru public law 2020-2021 thru Bipartisan Budget Act of 2018
Budget: $20.18 Million ($12.282 Federal: $7.898 Cost-shared)
Non-Federal Sponsor: Texas General Land Office
Schedule: Recon: 2014-2015 Feasibility Study Start: Oct 2016 Scheduled Completion: May 2021
Multi-Purpose: Coastal Storm Risk Management and Ecosystem Restoration
Scope: Develop a comprehensive plan to determine the feasibility of carrying out projects for flood damage reduction, hurricane and storm damage reduction, and ecosystem restoration in the coastal areas of the State of Texas. The comprehensive plan shall provide for the protection, conservation, and restoration of wetlands, barrier islands, shorelines, and related lands and features that protect critical resources, habitat, and infrastructure from the impacts of coastal storms, hurricanes, erosion, and subsidence http://CoastalStudy.Texas.gov US Army Corps Of Engineers® NATIONAL SIGNIFICANCE CoastalTXStudy
Population Centers Coastal Ecosystems • >$125B assets at risk, • Wetlands, seagrass beds, growing to $200B oyster reefs, dunes, and • 18 coastal counties beaches • 6.1 million residents, growing • Critical threatened and to 9M in 50 yrs endangered species habitat • >24% of the TX population • Nursery habitat and significant commercial fisheries for Critical Infrastructure oysters, shrimp, and finfish • Nationally ranked deep-draft Critical Natural Features ports • 450 miles of Gulf Intracoastal • 2 National Estuary Program Waterway (GIWW) sites • 40% of the Nation’s • Central Flyway Migration petrochemical industry Corridor • 25% of national petroleum- • The Laguna Madre - a rare refining capacity hypersaline lagoon • NASA • Padre Island National Seashore • UTMB – Level 4 Viral • 12 National Wildlife Refuges Laboratory 3 http://CoastalStudy.Texas.gov US Army Corps Of Engineers® STORM OF 1900 CoastalTXStudy ANTICIPATED RELATIVE http://CoastalStudy.Texas.gov US Army Corps Of Engineers® SEA LEVEL CHANGES CoastalTXStudy
Upper Texas Coast Break Point in Sea Level Change (about 3.5 feet)
Year 2300 (Low) Year 2130 (Intermediate) Year 2075 (High) http://CoastalStudy.Texas.gov US Army Corps Of Engineers® MULTIPLE LINES OF DEFENSE CoastalTXStudy
1st Line: Hardened Perimeter at the Gulf Inlet Storm Surge Gates
Next Lines: Lateral and Interior Features Dune Flanks Ring Barrier Upper West Bay – Clear Creek, Dickinson & Non-Structural GIWW Breakwaters Oyster Reefs ER Site-specific restoration features (e.g., marsh creation) http://CoastalStudy.Texas.gov US Army Corps Of Engineers® SHORELINE EROSION CoastalTXStudy SITE SELECTION STRATEGY
The Goal: Synergize with ongoing initiatives to promote resilience at a systems scale: TX GLO’s MP RESTORE Act Sites USFWS NWRs NRDA Our Approach • Formulated a list of potential sites • Developed site selection criteria to characterize the sites • Used Subject Matter Experts (SMEs) to screen and select sites based on these criteria • Quantified the benefits using Habitat Evaluation Procedures (HEP) & compared that to the costs (construction/operations/maintenance)
• Recommended a combination of sites for inclusion8 in the comprehensive Tentatively Selected Plan (TSP) http://CoastalStudy.Texas.gov US Army Corps Of Engineers® RECOMMENDED PLAN CoastalTXStudy
Revised Coastal Resilience Comprehensive Strategy Coastal Storm Risk Management o 2 large & 2 small sector gates o 15 vertical lift gates & 16 monoliths o 42 mi of Gulf-side dune/beach barrier o 18 mi of ring barrier o 4-ft high extension of the seawall o Gated closures at four locations o Non-structural measures on the mainland o 2 mi beach/dunes on South Padre
Gulf of Mexico
Bolivar Peninsula Galveston Island Galveston Bay
Ecosystem Restoration (6,000+ ac) o 737 ac of breakwaters o 838 ac of bird islands o 1,985 ac of marshes o 44 ac of oyster reefs o 2,519 ac of dunes/beaches http://CoastalStudy.Texas.gov US Army Corps STORM SURGE GATES
Of Engineers® (DESIGN IN PROGRESS) CoastalTXStudy
Galveston Bay Deep Section Smaller Sector Gates Sector Gates (2 Large) (2 Small)
Galveston Island
Intermediate Sections Bolivar Shallow Section Peninsula (15 Vertical Lift Gates) Gulf of Mexico (16 Environmental Gates) http://CoastalStudy.Texas.gov US Army Corps NATURE-BASED SOLUTIONS:
Of Engineers® DUNE & BEACHES CoastalTXStudy Conceptual Model 11, 2019 using Agency (GLO, NPS, TPWD, and ERDC) FeedbackUpdated on December
Parameters selected based Substrate: on analysis using GLM and Sand vs. Clay random forest models • Nest elevation • Distance from Habitat Recreational shoreline Kemp’s Beach Use • Maximum dune ridley nesting slope Morphological Environmental Anthropogenic Artificial Lighting • Average beach slope
Total Dune Height = Dune Elevation + Dune Vegetation Dune Vegetation Height
퐻푆퐼 = 퐸푙푒푣푎푡푖표푛 ∗ 푇표푡푎푙 퐷푢푛푒 퐻푒푖푔ℎ ∗ 푆푢푏푠푡푟푎푡푒 ∗ 푀푎푥 퐷푢푛푒 푆푙표푝푒 ∗ 퐴푣푒푟푎푔푒 퐵푒푎푐ℎ 푆푙표푝푒 Beach and Dune Restoration and Habitat Modeling
• Kemp’s Ridley sea turtle chosen as target species for modeling because they are the most frequent sea turtle nester on the Texas Gulf Coast and they are considered sentinel species • Figures from M.S. Thesis by Michelle F. Culver (2018), Beach Geomorphology and Kemp’s Ridley (Lepidochelys kempii) Nest Site Selection along Padre Island, TX, USA
Bolivar beach, Examples of Beach Profiles thought not to be Examples of Beach Profiles thought to be conducive to conducive to Kemps Ridley nesting September 21, 2019 Kemps Ridley nesting
13 http://CoastalStudy.Texas.gov US Army Corps GALVESTON RING BARRIER
Of Engineers® (DESIGN IN PROGRESS) CoastalTXStudy http://CoastalStudy.Texas.gov US Army Corps GALVESTON RING BARRIERRoad Closure Railroad Gate Floodwall® Of Engineers (DESIGN IN PROGRESS) CoastalTXStudy
Combi-Wall Circulation Gates Navigation Gate Vertical Lift Gate
Slide Gate Flap Gate Pump Station http://CoastalStudy.Texas.gov US Army Corps ECOSYSTEM RESTORATION
Of Engineers® (DESIGNS IN PROGRESS) CoastalTXStudy
1. Shoreline Protection – Reduce/prevent shoreline erosion of barrier system shorelines, estuarine bay shorelines, and channel shorelines. 2. Hydrologic Connectivity – restore and/or create hydrologic connectivity of sensitive estuarine systems. 3. Estuarine Bay Systems Restoration – Restore, create, and/or protect critical estuarine wetlands, tidal flats, etc. 4. Barrier Beach, Dune and Back Marsh Restoration – Nourish and protect barrier beach, dune, and back mar 5. Oyster Reef Restoration – Restore and/or create important oyster reefs. 6. Neotropical Migratory Bird Habitat Restoration – Restore and/or create important habitat used by migratory birds 7. Bird Island Rookeries Restoration – Restore and/or create important islands used as bird rookeries. 8. Restore Habitat Used by Species of Concern – Restore and/or create habitat (important, critical, essential, and other habitat types) used by species of concern, such as federally- listed species, shorebirds, federally-managed aquatic species (e.g., essential fish habitat [EFH]), and others. G28 - BOLIVAR PENINSULA AND WEST BAY GIWW SHORELINE AND ISLAND PROTECTION
LEGEND DESIGN CONCEPTS: OUT-YEAR MARSH NOURISHMENT • Place breakwaters first MARSH RESTORATION • Spaced to allow hydrologic exchange EAST GALVESTON BAY BREAKWATERS GULF INTRACOASTAL WATERWAY (GIWW) • Adaptive out-year nourishments to maintain heights with RSLR (not in recommended Breakwaters plan)
GIWW Breakwaters: 27 miles Alignment: North of GIWW in West Bay Target Height: +7ft Target Width: 46ft Marsh Slope: 2H:1V Material Qtys: 1.9M tons Restoration Primary Sourcing: Commercial sources Out-year Nourishment GULF OF MEXICO Marshes: 32 acres
Seaward Notes: Alignment: Behind breakwaters 3ft Side Top Elev. +7ft All elevations in feet NAVD88 Target Height: +2ft Target Width: Varies Draft All drawings are “Construction” Profiles Armor Layer 3ft Slope: 5H:1V Material Qtys: ~23K cy Elev. +1ft Specifications Primary Sourcing: GIWW BUDM and/or Mining Bed Layer 1ft Thick Bottom Elev. -3ft Other Options: Big Reef, GISS Bolivar Flare Sources Sediment Trap, HSC BUDM and/or Mining, Geotextile 46ft Sabine and Trinity River Paleo Channels BREAKWATER
Confinement Berm 9ft Top Elev. +2ft Marsh Nourishment Match Elev. +1.2ft Existing Grade
MARSH RESTORATION Match Existing Grade 17 NATIONAL ENVIRONMENTAL http://CoastalStudy.Texas.gov US Army Corps Of Engineers® POLICY ACT (NEPA) 1969 CoastalTXStudy
Environmental Impact Analysis Conceptual Tiered NEPA Approach
• NEPA is the nation’s foremost environmental law Chief's PH 1 PH 2 PH 3 PH 4 ADM Constr. Constr. Constr. Constr. • NEPA drives our process by requiring the identification Phase III 1rst EIS ENR #1 PED of direct, indirect and cumulative impacts Final SEIS/LRR Report Phase I Gate • Tiered NEPA has been authorized for this study PED Phase IV SEIS/ ENR #2 LRR Phase II PED Levee PED SEIS/LRR SEIS / LRR Analyses Underway
• Direct Impacts Project Lifespan - Habitat Evaluation Procedures (HEP) - Quality x Quantity of Species Habitat Particle Track Modeling (PTM) - Advanced Hydrologic Modeling - Salinity, Velocity & Sediment Transport - Particle Track Modeling • Larval Movement & Recruitment Success • Indirect & Cumulative Impacts
Mitigation Planning Underway http://CoastalStudy.Texas.gov US Army Corps Of Engineers® PUBLIC OUTREACH CoastalTXStudy
• Formal Comment Period (45 days) • Formal Meetings (NEPA Required) • Public Open Houses • CWGs • Social Media • Tech Talks • Newsletters • Email lists • Stakeholder Briefings
More opportunities to engage are on the project horizon . . . . .remember Tiered NEPA! http://CoastalStudy.Texas.gov US Army Corps Of Engineers® SCHEDULE CoastalTXStudy
STUDY
Identify Problems & Identify Tentatively Complete Final Identify Opportunities Selected Plan Analysis Recommended Plan
2nd Release & Public Review
ALTERNATIVESALTERNATIVES DRAFT RECOMMEND FINAL SCOPING FORMULATION REPORT PLAN REPORT
Alternative Tentatively Agency Decision Measures Selected Plan Chief’s Report Milestone (ADM) Milestone (AMM) (TSP) May 2021 Apr 2019 Jun 2016 May 2018
Public Review & Provide Recommendation Get Public Input Conduct Analysis Comment to Congress http://CoastalStudy.Texas.gov US Army Corps Of Engineers® SCHEDULE CoastalTXStudy http://CoastalStudy.Texas.gov US Army Corps Of Engineers® WATCH THIS SPACE!! CoastalTXStudy G28 - BOLIVAR PENINSULA AND WEST BAY GIWW SHORELINE AND ISLAND PROTECTION
23 G28 - BOLIVAR PENINSULA AND WEST BAY GIWW SHORELINE AND ISLAND PROTECTION
LEGEND DESIGN CONCEPTS: OUT-YEAR MARSH NOURISHMENT • Place breakwaters first MARSH RESTORATION • Slotted to allow hydrologic exchange EAST GALVESTON BAY BREAKWATERS GULF INTRACOASTAL WATERWAY (GIWW) • Adaptive out-year nourishments to maintain heights with RSLR (not in recommended Breakwaters plan)
GIWW Breakwaters: 27 miles Alignment: North of GIWW in West Bay Target Height: +7ft Target Width: 46ft Marsh Slope: 2H:1V Material Qtys: 1.9M tons Restoration Primary Sourcing: Commercial sources Out-year Nourishment GULF OF MEXICO Marshes: 32 acres
Seaward Notes: Alignment: Behind breakwaters 3ft Side Top Elev. +7ft All elevations in feet NAVD88 Target Height: +2ft Target Width: Varies Draft All drawings are “Construction” Profiles Armor Layer 3ft Slope: 5H:1V Material Qtys: ~23K cy Elev. +1ft Specifications Primary Sourcing: GIWW BUDM and/or Mining Bed Layer 1ft Thick Bottom Elev. -3ft Other Options: Big Reef, GISS Bolivar Flare Sources Sediment Trap, HSC BUDM and/or Mining, Geotextile 46ft Sabine and Trinity River Paleo Channels BREAKWATER
Confinement Berm 9ft Top Elev. +2ft Marsh Nourishment Match Elev. +1.2ft Existing Grade
MARSH RESTORATION Match Existing Grade 24 G28 (WEST) - BOLIVAR PENINSULA AND WEST BAY GIWW SHORELINE AND ISLAND PROTECTION
LEGEND DESIGN CONCEPTS: ISLAND RESTORATION • Place breakwaters first • Slotted to allow hydrologic exchange Marsh OUT-YEAR MARSH • Adaptive out-year nourishments to maintain Restoration NOURISHMENT MARSH RESTORATION heights with RSLR (not in recommended BREAKWATERS plan) • Culch placed within reef template – final Out-year OYSTER REEF elevation and slopes TBD Nourishment GULF INTRACOASTAL WATERWAY (GIWW) Breakwaters: 9 miles Breakwaters Alignment: North of GIWW in West Bay GIWW Target Height: +7ft Target Width: 46ft Slope: 2H:1V Material Qtys: ~627K tons WEST GALVESTON BAY Primary Sourcing: Commercial sources Oyster Island Restoration Reefs Marshes: 640 acres Alignment: Behind breakwaters Seaward Target Height: +2ft Target Width: Varies 3ft Side GIWW Island Creation Top Elev. +7ft Slope Face Elev. +9ft Slope: 5H:1V Material Qtys: ~459K cy Protected by ACB 3ft Primary Sourcing: GIWW BUDM and/or Mining Armor Layer Existing GIWW Elev. +1ft Channel Slope Other Options: Big Reef, GISS Bolivar Flare (<3H:1V) Bed Layer 1ft Thick Bottom Elev. -3ft Elev. -10ft to -14ft Sediment Trap, HSC BUDM and/or Mining, 400ft – 600ft Elevation of Existing Bottom of Sabine and Trinity River Paleo Channels Geotextile Proposed Fill Placement Varies 46ft Existing GIWW 0ft – 6ft Channel Bottom Islands: 326 acres (5 mi long) BREAKWATER ISLAND RESTORATION Alignment: South of GIWW in West Bay Sources Target Height: +9ft Target Width: 400-600ft Slope: 5H:1V Material Qtys: 5.8mcy Confinement Berm 9ft Top Elev. +2ft Marsh Nourishment Primary Sourcing: Dredging Match Elev. +1.2ft Existing Grade Oyster Reefs: 18 acres (26,280 linear ft) Alignment: South of GIWW & islands MARSH RESTORATION Match Existing Grade complexes 25 Notes: Benefits: 589 Net AAHUs All elevations in feet NAVD88 Draft Specifications All drawings are “Construction” Profiles Cost: $757K - $989K (w/o out-yr nourishments) B2 - FOLLETS ISLAND GULF BEACH AND DUNE RESTORATION
26 B2 - FOLLETS ISLAND GULF BEACH AND DUNE RESTORATION
Beach & Dune Complexes: ~10.1mi (1,114 ac) Alignment: Current dune line
CHRISTMAS BAY Target Dune Height: 10-12ft Target Dune Width: 150ft Target Beach Width: 550-600ft DRUM BAY Slope: 10H:1V Material Quantities: ~8.78mcy Primary Sourcing: Shoreface dredging FOLLETS ISLAND (purple) Other Options: Sabine/Heald Banks (pink)
Dune & Beach Nourishment Design Concepts: GULF OF MEXICO • Nourish with sand only - no engineered LEGEND dunes
DUNE & BEACH NOURISHMENT • Fill the road gaps roads GULF INTRACOASTAL WATERWAY (GIWW) • Walk- & Drive-overs • Must address drainage issues 150ft Dune Notes: Draft Specifications All elevations in feet NAVD88 10ft Wide Dune Crest All drawings are “Construction” Profiles 750ft Benefits: 200 Net AAHUs (w/o out-yr nourishments) 10ft Dune Crest Cost: $433K - $600K EL +12ft 550ft Berm Crest 750ft EL +5ft Sources 550ft Wide Berm Crest Drive-Over Example 600ft Berm
27 B12 - BASTROP BAY, OYSTER LAKE, WEST BAY, AND GIWW SHORELINE RESTORATION
28 B12 - BASTROP BAY, OYSTER LAKE, WEST BAY, AND GIWW SHORELINE RESTORATION
LEGEND DESIGN CONCEPTS: OUT-YEAR MARSH NOURISHMENT BREAKWATERS • Place breakwaters first • Slotted to allow hydrologic exchange MARSH RESTORATION OYSTER REEF Oyster • Adaptive out-year nourishments to maintain GULF INTRACOASTAL WATERWAY (GIWW) Reefs heights with RSLR (not in recommended plan) Out-year • Culch placed within reef template – final Nourishment elevation and slopes TBD 36 Breakwaters: 43.2 miles WEST 332 GALVESTON Alignment: Western side of West Bay, and BAY FREEPORT Cowtrap Lakes, and along selected segments of CHRISTMAS BAY the GIWW in Brazoria County GALVESTON ISLAND Target Height: +7ft Target Width: 46ft FOLLETS ISLAND Slope: 2H:1V Material Qtys: ~3.0M tons Primary Sourcing: Commercial sources Marsh Restoration GULF OF MEXICO Breakwaters Marshes: 551 acres Alignment: Behind breakwaters Seaward Notes: 3ft Side Target Height: +2ft Target Width: Varies Top Elev. +7ft All elevations in feet NAVD88 All drawings are “Construction” Profiles Slope: 5H:1V Material Qtys: ~2mcy 3ft Armor Layer Primary Sourcing: GIWW BUDM and/or Mining Elev. +1ft Sources Bed Layer 1ft Thick Other Options: Big Reef, GISS Bolivar Flare Bottom Elev. -3ft Sediment Trap, HSC BUDM and/or Mining, Geotextile Sabine and Trinity River Paleo Channels 46ft BREAKWATER Oyster Reefs: 3,708 linear ft Alignment: Designed to reduce breaching of Confinement Berm Oyster Lake into the West Bay 9ft Top Elev. +2ft Marsh Nourishment Match Elev. +1.2ft Benefits: 1,031 Net AAHUs Existing Grade Cost: $517K - $718K (w/o out-yr nourishments)
MARSH RESTORATION Match Existing Grade 29 Draft Specifications M8 - EAST MATAGORDA BAY SHORELINE PROTECTION
30 M8 - EAST MATAGORDA BAY SHORELINE PROTECTION
LEGEND DESIGN CONCEPTS: ISLAND RESTORATION • Place breakwaters first OUT-YEAR MARSH • Slotted to allow hydrologic exchange NOURISHMENT • Adaptive out-year nourishments to maintain MARSH RESTORATION heights with RSLR (not in recommended Out-year plan) Nourishment BREAKWATERS OYSTER REEF • Culch placed within reef template – final GULF INTRACOASTAL elevation and slopes TBD WATERWAY (GIWW) Breakwaters: 8.9 miles Alignment: Along unprotected segments of the GIWW, along the Big Boggy NWR shoreline, and eastward of the end of East Matagorda Bay (not Island Oyster Marsh where the GIWW is stabilized adjacent to PAs) Restoration Reefs Restoration Target Height: +7ft Target Width: 46ft Breakwaters Slope: 2H:1V Material Qtys: ~634K tons Primary Sourcing: Commercial sources EAST MATAGORDA BAY Marshes: 239 acres Alignment: Behind breakwaters 3ft Seaward GIWW Island Creation Top Elev. +7ft Side Target Height: +2ft Target Width: Varies Slope Face Elev. +9ft Protected by ACB Armor Layer 3ft Slope: 5H:1V Material Qtys: ~670,000cy Elev. +1ft Existing GIWW Channel Slope Primary Sourcing: CO River Diversion Delta, Bed Layer 1ft Thick (<3H:1V) Bottom Elev. -3ft GIWW BUDM and/or mining, Paleo Elev. -10ft to -14ft 400ft – 600ft Colorado/Brazos Deltas Elevation of Existing Bottom of Geotextile 46ft Proposed Fill Placement Varies Existing GIWW 0ft – 6ft Channel Bottom Islands: 92.7 acres (3.5 miles) BREAKWATER ISLAND RESTORATION Alignment: South of GIWW in West Bay Sources Target Height: +9ft Target Width: 400-600ft Confinement Berm Slope: 5H:1V Material Qtys: 2mcy 9ft Top Elev. +2ft Marsh Nourishment Match Elev. +1.2ft Primary Sourcing: Dredgin Existing Grade Oyster Reefs: 31,355 linear ft Alignment: bayside of channel MARSH RESTORATION Match Existing Grade 31 Notes: Benefits: 144 Net AAHUs All elevations in feet NAVD88 Draft Specifications All drawings are “Construction” Profiles Cost: $150K - $210K (w/o out-yr nourishments) CA5 – KELLER BAY RESTORATION
32 CA5 – KELLER BAY RESTORATION
LEGEND DESIGN CONCEPTS: SUBMERGED VEGETATION • Place breakwaters first OUT-YEAR MARSH • Slotted to allow hydrologic exchange KELLER BAY NOURISHMENT • Adaptive out-year nourishments to maintain BREAKWATERS heights with RSLR (not in recommended OYSTER REEF plan) Oyster GULF INTRACOASTAL • Culch placed within reef template – final Reef Submerged WATERWAY (GIWW) elevation and slopes TBD Vegetation Breakwaters: 3.8 miles Alignment: Along Matagorda Bay side Target Height: +7ft Target Width: 46ft Slope: 2H:1V Material Qtys: 271K tons Primary Sourcing: Commercial sources Out-year Breakwaters Nourishment MATAGORDA BAY Submerged Vegetation: 296 acres Configuration: Spacing and plant types TBD
3ft Seaward Top Elev. +7ft Side Oyster Reefs: 12,213 linear ft
Armor Layer 3ft Elev. +1ft SUBMERGED VEGETATION Bed Layer 1ft Thick Bottom Elev. -3ft Sources Benefits: 226 Net AAHUs Geotextile 46ft Cost: $47K - $66K (w/o out-yr nourishments) BREAKWATER
Confinement Berm 9ft Top Elev. +2ft Marsh Nourishment Match Elev. +1.2ft Existing Grade
MARSH RESTORATION Match Existing Grade
Notes: 33 All elevations in feet NAVD88 Draft Specifications All drawings are “Construction” Profiles CA6 – MAGNOLIA TO PORT O’CONNOR SHORELINE PROTECTION AND RESTORATION
34 CA6 – MAGNOLIA TO PORT O’CONNOR SHORELINE PROTECTION AND RESTORATION
LEGEND DESIGN CONCEPTS: MARSH RESTORATION • Place breakwaters first POWDERHORN BREAKWATERS • Slotted to allow hydrologic exchange LAKE GULF INTRACOASTAL • Adaptive out-year nourishments to maintain Marsh Restoration WATERWAY (GIWW) heights with RSLR (not in recommended plan) • Culch placed within reef template – final elevation and slopes TBD
INDIANOLA Breakwaters: 5 miles Alignment: For shoreline stabilization fronting portions of Indianola, Powderhorn Lake estuary, and TPWD’s Powderhorn Ranch Target Height: +7ft Target Width: 46ft Breakwaters Slope: 2H:1V Material Qtys: 356K tons MATAGORDA BAY Primary Sourcing: Commercial sources Marshes: 531 acres Alignment: Behind breakwaters 3ft Seaward Target Height: +2ft Target Width: Varies Top Elev. +7ft Side Draft Specifications Slope: 5H:1V Material Qtys: ~641,000cy Armor Layer 3ft Elev. +1ft Primary Sourcing: Matagorda Ship Channel Sources Bed Layer 1ft Thick BUDM and/or mining Bottom Elev. -3ft Sources Geotextile 46ft BREAKWATER
Confinement Berm 9ft Top Elev. +2ft Marsh Nourishment Match Elev. +1.2ft 20 Net AAHUs Existing Grade Benefits: Cost: $64K - $88K (w/o out-yr nourishments) MARSH RESTORATION Match Existing Grade Notes: 35 All elevations in feet NAVD88 All drawings are “Construction” Profiles SP1 – REDFISH BAY PROTECTION AND ENHANCEMENT
36 SP1 – REDFISH BAY PROTECTION AND ENHANCEMENT
LEGEND DESIGN CONCEPTS: • Place breakwaters first Island SUBMERGED VEGETATION ISLAND RESTORATION • Slotted to allow hydrologic exchange Restoration BREAKWATERS • Adaptive out-year nourishments to maintain heights with RSLR (not in recommended OYSTER REEF plan) GULF INTRACOASTAL WATERWAY (GIWW) • Culch placed within reef template – final elevation and slopes TBD Breakwaters Breakwaters: 7.4 miles Oyster Reefs Submerged Vegetation Alignment: Along the unprotected GIWW shoreline, along the backside of Redifish Bay, and on the bayside of the restored islands Target Height: +7ft Target Width: 46ft Slope: 2H:1V Material Qtys: 524K tons Primary Sourcing: Commercial sources
Islands: 391.4 acres 3ft Seaward Alignment: South of GIWW in West Bay Top Elev. +7ft Side Target Height: +9ft Target Width: 400-600ft Armor Layer 3ft Elev. +1ft Slope: 5H:1V Material Qtys: 2mcy SUBMERGED VEGETATION Bed Layer 1ft Thick Primary Sourcing: Dredgin Bottom Elev. -3ft Sources Geotextile 46ft Submerged Vegetation: 3,026 acres BREAKWATER Configuration: Spacing and plant types TBD
Confinement Berm Oyster Reefs: 7,392 linear ft 9ft Top Elev. +2ft Marsh Nourishment Match Elev. +1.2ft Existing Grade
Benefits: 3,184 Net AAHUs MARSH RESTORATION Match Existing Grade Cost: $274K - $384K (w/o out-yr nourishments) Notes: 37 All elevations in feet NAVD88 Draft Specifications All drawings are “Construction” Profiles W3 - PORT MANSFIELD CHANNEL AND ISLAND ROOKERY RESTORATION
38 W3 - PORT MANSFIELD CHANNEL AND ISLAND ROOKERY RESTORATION
Island LEGEND DESIGN CONCEPTS: DUNE & BEACH • Restore circulation in the Lower Laguna Restoration REDFISH BAY RESTORATION Madre with dredging. The sediment from the GIWW ISLAND RESTORATION dredging will be placed on a bird island and BORROW SOURCE north of the Mansfield Pass jetty. Breakwater BREAKWATERS GULF INTRACOASTAL Beach & Dune Complexes: ~9.5mi Sources WATERWAY (GIWW) Alignment: Current dune line on the ocean- side of island/peninsula Target Dune Height: 10-12ft Target Dune Width: 150ft
SOUTH PADRE ISLAND Target Beach Width: 550-600ft SOURCE Slope: 10H:1V MATERIAL Material Quantities: TBD Primary Sourcing: TBD Beach & Dune Restoration GULF OF MEXICO Breakwaters: 0.70 miles 750ft Alignment: Surrounding bird island Target Height: +7ft Target Width: 46ft 10ft Dune Crest Draft Specifications EL +12ft 550ft Berm Crest Notes: Slope: 2H:1V Material Qtys: 46.7K tons EL +5ft All elevations in feet NAVD88 Primary Sourcing: Commercial sources All drawings are “Construction” Profiles
BEACH & DUNE RESTORATION Islands: 27.8 acres Alignment: South of GIWW in West Bay Target Height: +9ft Target Width: 400-600ft Slope: 5H:1V Material Qtys: 488K cy Island Creation 3ft Slope Face Top Elev. +7ft Elev. +9ft Primary Sourcing: Port Mansfield Channel Protected by ACB Armor Layer 3ft Existing GIWW Elev. +1ft Channel Slope (<3H:1V) Bed Layer 1ft Thick Elev. -10ft to -14ft Bottom Elev. -3ft 400ft – 600ft Elevation of Existing Bottom of Benefits: 89 Net AAHUs Proposed Fill Placement Varies Geotextile39 Existing GIWW 0ft – 6ft 46ft Channel Bottom Cost: $36K - $50K (w/o out-yr nourishments) ISLAND RESTORATION BREAKWATER http://CoastalStudy.Texas.gov US Army Corps STUDY UPDATE:
Of Engineers® HOW DID WE GET HERE? CoastalTXStudy
ALT A: COASTAL BARRIER ALT B: MODIFIED BARRIER (TX CITY) ALT C: MID-BAY BARRIER
ALT D1: UPPER BAY (SH 146) ALT D2: BAY RIM PROJECT COSTS http://CoastalStudy.Texas.gov US Army Corps Of Engineers® IS IT WORTH IT? CoastalTXStudy
The NED/NER Plan must balance: Projected Costs Engineering soundness Coastal Barrier: $14.2B-$19.9B Environmental acceptability Economically justifications Ecosys. Restoration: $8.9B-11.9B South Padre CSRM: $71.6-$83.1M • Unity: Benefits Equal Cost TOTAL: $23B - $32B
• Benefits include quantitative, qualitative, monetized & non- monetized units
• Locally Preferred Plan (LPP) is a plan that is preferred by the non-Federal sponsor over the NED/NER plan, and is sometimes recommended for project authorization instead (with caveats) Recovery Costs for Past Storms: • LPPs must be evaluated just as the Federal Plan (costs, impacts, Hurricane Ike (2008): $38B benefits) Hurricane Harvey (2017): $125B