Phase I Complete - Brazos River Erosion Control Project (February 11, 2022)
Fort Bend County Levee Improvement District No. 7 (FBCLID 7) has completed engineering and design for the Brazos River Erosion Control Project.
This milestone also completes Phase I of the District’s Federal Emergency Management Agency (FEMA) Hazard Mitigation Grant Program. As of this update, FBCLID 7 has submitted the final design and other engineering documents to FEMA for review. FEMA must complete a successful review of all design documents before Phase II grant funding is awarded for construction. To be eligible for FEMA reimbursement, FBCLID 7 cannot start the construction bidding process until the Phase II grant is approved. The original project schedule assumed two months for FEMA Phase II approval, but recent reviews are taking up to 3-4 months.
The FBCLID 7 construction bidding process will begin as soon as Phase II grant approval is received from FEMA. Furthermore, the project schedule estimates at least 3 months between the start of bidding and a contractor mobilizing on the project. When the contractor mobilizes, it will take approximately one year to complete construction, depending on weather and Brazos River conditions. The current schedule estimates construction beginning in August 2022 and project completion in August 2023. As noted previously, the project schedule will be controlled by FEMA’s Phase II review process over the next few months.
The current construction cost estimate for the Brazos River Erosion Control Project is $53,800,000, but FBCLID 7 anticipates that more than 90% of that cost will be reimbursed by FEMA and the Texas Division of Emergency Management (TDEM). The FEMA grant will reimburse 75% of all eligible expenses, and typically the remaining 25% would be considered FBCLID 7’s local cost share. However, the District qualifies for additional assistance from TDEM which covers 75% of FBCLID 7’s 25% cost share. This means the ultimate cost to FBCLID 7 residents is approximately $3,400,000, or 6.25% of the total construction cost.
To date, FEMA has already approved almost $700,000 in reimbursements for Phase I engineering and design expenses. The project budget estimates more than $50,000,000 in FEMA and TDEM reimbursements will be received by FBCLID 7, and these funds will be used to pay off existing debt and fund future capital projects.
The final layout for the Brazos River Erosion Control Project is included below with the main design elements highlighted. To begin, approximately 200,000 cubic yards of material will be removed from the Brazos River bank to provide a more gradual slope down to the water. This large amount of excavation will fill more than 20,000 dump trucks. Next, steel sheet pile will be driven into the bottom of the Brazos River to create six bendway weirs. The bendway weirs are design to “train” the river by gradually restoring bank erosion and shifting the centerline of the Brazos to the south and away from the FBCLID 7 levee. The sheet piles are protected by 30-inch stone rip-rap that is placed in the river and highlighted below in orange. The bottom, or toe, of Brazos River bank will then be lined with 24-inch stone riprap to construct more than 3,000 feet of Launching Stone Toe Protection (LSTP), highlighted in purple. If scouring and erosion continue below the water, the LSTP is constructed to fill any voids using more than 50,000 cubic yards of granite boulders. The upper slopes of the riverbank will be lined with more than 40,0000 cubic yards of 15-inch stone rip-rap to provide additional erosion protection, highlighted in green. Finally, a gated maintenance road will be added to provide access for future erosion repairs, highlighted in blue. After the project is complete, FBCLID 7 will also coordinate soccer field restoration with the NTRA.
Another Brazos River Erosion Control Project milestone was achieved in January 2022 when four CenterPoint power poles were removed from the transmission line that is located inside the project limits.
Brazos River Erosion Control Project Design
Example photograph of Stone Rip-rap (Homochitto River, MS)
Rendering of stone rip-rap and bendway weirs