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“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.”

USACE GALVESTON DISTRICT BENEFICIAL USE AND IMPLEMENTATION OF REGIONAL SEDIMENT MANAGEMENT MEASURES

Tricia Campbell, Operations ManagerLisa Finn, Environmental Resource ManagerB. Steven Howard, Operations Manager

Galveston District, U.S. Army Corps of EngineersNovember 8, 2018

SWG Beneficial Use Project Overview• Galveston Beach Placement• Channel to Port Mansfield (upcoming)• Brazos Island Harbor (BIH)• Bessie Heights• Pierce Marsh

SWG RSM study overview• Selected Studies• Implementation of RSM Studies• Upcoming RSM Study (FY19)

AGENDA

3

Beach placement location

Sand source

Galveston Beneficial Use Beach Placement (2015)

Partnered with the Texas General Land Office and Galveston Island Park Board of Trustees to place material from channel on beach in lieu of offshore placement

5Galveston Beneficial Use Beach Placement (2015)

Completed by Great Lakes Dredge & Dock Company, LLCTotal Contract $20,620,530.

– $11,761,530 Federal Dredging costs– $ 8,859,000 Non-Federal Beach Placement costs

Approximately 500,000 CY placed, 4500’ of beach constructed

Examples of Potential Alignments

Channel to Port Mansfield Beneficial Use Project

Agency Coordination:• Texas GLO • USFWS• TPWS• Coastal Bend Bays

and Estuaries Program

• NOAA Fisheries provided comments

A Laguna Madre ICT meeting is scheduled for November 9th

Beach Nourishment

•3000 feet of beach nourishment

•City of South Padre in background

•Hydraulic pipeline at right

Brazos Island Harbor Beneficial Use Project

Sabine Neches Waterway – Maintenance dredging of Neches River Middle Reach typically occurs every 5 years

SWG partnered with the Texas General Land Office and the Sabine Neches Navigation District to place material from channel in Bessie Heights marsh restoration project in lieu of upland placement.

Bessie Heights Beneficial Use Marsh Creation

Maintenance dredging of the Gulf Intracoastal Waterway, Causeway to Bastrop Reach typically occurs every 3 years

SWG partnered with the Texas General Land Office, Galveston Bay Foundation and State and Federal Resource areas to place material from GIWW into Pierce Marsh

Contract completed by Mike Hooks, Inc. in July 2016

Pierce Marsh Beneficial Use Marsh Restoration

Pierce Marsh Construction: 144,000 CY and 11,800 linear feet of containment berms

Pierce Marsh Beneficial Use Marsh Restoration

SWG selected for RSM studies FY12-19 (green = implementing)

• FY12: Matagorda Bay RSM Study• FY13: GIWW RSM (West Galveston Bay)• FY14: Galveston Entrance Channel RSM• FY15: Lower Matagorda Bay RSM• FY16: GIWW-CCSC Intersection Shoaling• FY17: GIWW-Bolivar Flare Shoaling • FY18: Utilization and Design Considerations for Channel

to Victoria (CTV) BU Sites• FY19 (upcoming study): GIWW Caney Creek RSM

Regional Sediment Management (RSM) Studies

Description/Challenge• Area of Extensive Shoaling in Matagorda

Ship Channel• Annual Draft Restrictions = Annual Dredging

Requirements• Limited Funding for Dredging

Goals/Issues to Address• Determine source of sediment• Develop alternatives to reduce the

deposition of sediment into the ship channel• Implement alternative(s) which can

effectively reduce shoaling and provide increased time between dredging cycles

BLUF: Implementation of alternatives which can reduce shoaling in the Matagorda Ship Channel will benefit deep draft ports, industry, and USACE by enabling SWG to more effectively manage the maintenance of the channel in order to ensure reliable deep draft navigation.

Matagorda Bay Regional Sediment Management (RSM)

Artificial Island

Geotube

New PA

Matagorda Bay RSM Alternative Identification

Configuration Reach 1 Reach 2 Reach 3 Reach 1-3 % ReductionExisting Configuration

2.04 1.33 0.47 3.84

Create Artificial Island

1.90 1.24 0.44 3.58 -7

Place GeotubeAdjacent to Channel

1.00 1.44 0.41 2.85 -26

Relocate PAs to Opposite Side of Channel

1.10 1.35 0.44 2.89 -25

Cumulated Sediment Volume Change (cubic yard), Sep 2006 – Feb 2007

Matagorda Bay RSM Calculated Sediment Volume Change

15Matagorda Bay RSM Relocation of Placement Areas

16Matagorda Bay RSM Oyster Survey

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BLUF: SWG needs to identify sediment management options to prevent erosion of the Gulf Intracoastal Waterway (GIWW) Placement Areas. .

Objectives• Determine/Confirm Erosion of barrier islands

• Identify causes of erosion and erosion rates (sediment budget)

• Design/Evaluate methods to decrease erosion

Description/Challenges• PA’s along the GIWW are eroding on both the channel and the bay side due to currents, wind generated waves and ship wakes

• Once breached, material is deposited into the GIWW

• Once they become submerged they become potentially unavailable

PA 65

PA 64 PA 63

PA 62

GIWW RSM (West Galveston Bay)

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Rebuild Barrier Islands• Reduce shoaling, Improve Navigation Safety, Promote Seagrass• Section 1122 Study, TXDOT proposal• Pump out of existing upland sites and rebuild islands

• Work would occur all at one time• Regain capacity

GIWW RSM (West Galveston Bay)

Goal: Development of an alternative approach to managing dredged material for the GIWW, Channel to Victoria (CTV) project by assessing implementation of sites adjacent to the channel.

FY18 RSM Study Objectives:• Leverage historic or previously identified BU

sites/existing NEPA coordination• Will this increase shoaling?• Will this increase?• Identify other benefits

Site Utilization and Design Considerations for theGIWW, Channel to Victoria Project

GIWW, CTV Federal Navigation Project• Separately authorized from the GIWW Navigation Project• Segmented in 3 reaches and 1 spur channel• 37 Miles of Channel• Authorized Project Depth: -14’ MLLW (Channel to Seadrift

-11’ MLLW)Maintenance Dredging

• Lower Reach: • 9 Miles • Dredged 1.5 – 2 years• ~900k cy/cycle• Bird window closure – no dredging 15-Oct through

15-Apr• Channel to Seadrift:

• 2 Miles• Dredged 7 years• ~450k cy/cycle

• All material placed in upland confined placement areas

Benefit to USACE and the Nation

GIWW, CTV PAsChannel to Victoria Placement Areas

RSM Site Selections

Four Sites in RSM study:• Site 2• Site 3• Site 12• Site 15

Sites selected largely based on:• Location/pipeline distance• Size/capacity• Anticipated oyster mitigation

Site Utilization and Design Considerations for theGIWW, Channel to Victoria Project

Site 2

Site 2• Landmass created from previous dredging ops• ~22 acres

Implementation• Est. 100k cy to restore island• Next dredging cycle – FY20• Re-nourish with subsequent maintenance

cycles • Unconfined discharge• No/Minimal improvements prior to use

► Burning of site prior to placement of material –Coordinating with US FWS

Site Utilization and Design Considerations for theGIWW, Channel to Victoria Project

Site 2

Benefits to Federal Project:• Reduce cost to dredge

► Located adjacent to high shoaling area► Alternative PA is ~2.5 miles► Booster pump is not required

• No impact to shoaling rate

Additional Benefits/Considerations:• Create/enhance critical habitat – Whooping Crane

► Realize greater benefits of habitat via burning vegetation

► Isolated island - predator management

Site Utilization and Design Considerations for theGIWW, Channel to Victoria Project

Site 3

Site 3• Historically landmass present on western

border of site• Site delineation ~200 acres

Implementation• Construct revetment (potentially in FY19)

► RSM investigated hard structure along site► Construction in stages

• Potential for placement of material next dredging cycle in FY20

Site Utilization and Design Considerations for theGIWW, Channel to Victoria Project

Site 3

Implementation (Con’t)• Initial stages, developing as FY19

Capability

• RSM studied investigated revetment along nearly the whole site► Between two islands within the site► Construct in stages

• Oyster mitigation

Site Utilization and Design Considerations for theGIWW, Channel to Victoria Project

Site 3

Benefits to Federal Project:• Reduce cost to dredge

► Reduce pipeline length► Reduce/eliminate upland PA maintenance

• 30% reduced to shoaling rate• Improved navigation reduced fetch

Additional Benefits/Considerations:• Incidental nesting bird habitat

► Difficult predator management• Preferable area for salt marsh

► Potential to encourage disbursement of material during dredging operations

Site Utilization and Design Considerations for theGIWW, Channel to Victoria Project

Conclusion

Develop/implement alternative approach for managing dredged material on the Lower Reach of the GIWW, CTV Project

Benefits to the Navigation Project:• Reduce quantity of material dredged

(-15% average)• Reduce cost to dredge (-28%

average)

Additional Benefits:• Habitat creation/enhancement • Potentially reduce dredging frequency• Safer navigation• Additional capacity for the Project• Additional placement areas available

for emergency dredging

Leverage:• Existing NEPA coordinated sites• O&M funds

► Reduced cost to dredge► No negative impacts to the project

Site 2 is the most promising for implementation:• No/minimal costs prior to use• Greatest improvement to bird habitat

Site Utilization and Design Considerations for theGIWW, Channel to Victoria Project

29FY19 GIWW Caney Creek RSMRecent increase in shoaling rate at GIWW intersection with Caney Creek has resulted in frequent navigation restrictions and bi-annual dredging

Con

nect

with

Us!

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