Freshwater Bayou Bank Stabilization (ME-13)

By placing riprap in front of the existing shoreline, further wetland loss will be decreased dramatically. It is anticipated that open water areas behind the rock structure will accumulate sediments and eventually become vegetated.

Location

This project is located along the west bank of Freshwater Bayou Canal near Little Vermilion Bay, 4 miles southwest of Intracoastal City, Louisiana, in Vermilion Parish. It
extends north from North Prong and Belle Isle Bayou to Sixmile Canal.

Problems

Increased tidal action, saltwater intrusion, and boat wakes have accelerated erosion long the banks of the Freshwater Bayou Canal. The spoil banks have completely eroded in some areas. The remaining spoil banks along the southern reach of the project area separate Freshwater Bayou Canal from several interior marsh ponds. If the banks breach, shoreline erosion will accelerate interior marsh loss.

Restoration Strategy

The objective of this project was to prevent further wetland loss through the reduction of bank erosion and subsequent tidal scour of shoreline marshes. Approximately 23,193 linear feet of freestanding rock dike were constructed in shallow water along the west bank of Freshwater Bayou Canal (from its confluence with Sixmile Canal on the northern end and North Prong to the south).

Progress to Date

The local cost share for this project was provided by Acadian Gas Company. Construction began in March 1998 and was completed in May 1998. The monitoring plan was approved in February 1997. To date, monitoring has consisted of documenting the pre-construction shoreline position relative to the rock dike and a land-to-water analysis of the preconstruction aerial photography that was taken in January 1997. This project is on Priority Project List 5.

The project is on Priority Project List (PPL) 5.

The Federal Sponsor is National Resources Conservation Service

The Local Sponsor is CPRA.

Approved Date: 1996
Project Area: 1,724 acres
Approved Funds: $5.56 M
Total Est. Cost: $8.91 M
Net Benefit After 20 Years: 511 acres
Status: Completed June 1998
Project Type: Shoreline Protection

East Catfish Lake Marsh Creation and Shoreline Protection (TE-157)

Aerial view of marsh creation project in Terrebonne Parish.

Location

The project is located in Region 3, Terrebonne Basin, Terrebonne Parish.

Problems

Significant marsh loss has occurred east and south of Catfish Lake. Causes of marsh loss include the construction of numerous oil/gas canals, subsidence, and sediment deprivation. Between Catfish Lake and Golden Meadow Hurricane Protection Levee, very little marsh remains after the construction of an extensive network of oil/gas canals. Much of the remaining land in this area consists of spoil banks and isolated patches of marsh. From examination of aerial photography, the majority of this loss occurred during the 1960s and 1970s. Based on the hypertemporal analysis conducted by USGS for the extended project boundary, the land loss rate in the project area is -0.86% per year for the period 1984 to 2019. Shoreline erosion rates (1998-2017) range from 10 ft/yr along the eastern lake shoreline to 22ft/yr along the southern lake shoreline.

Restoration Strategy

The primary goal of this project are; 1) restore marsh habitat in the open water areas east and south of Catfish Lake, and 2) restore and protect the eastern and southern Catfish Lake shoreline. The specific goals of this project are; 1) create 235 acres of marsh, 2) nourish 71 acres of marsh, 3) protect the marsh creation cells from shoreline erosion.

Service goals include restoration/protection of habitat for threatened and endangered species and other at-risk species. This project would restore habitat potentially utilized by the black rail, which is proposed for listing as a threatened species. The project could also benefit other species of concern including the saltmarsh topminnow and seaside sparrow.

Sediment from Catfish Lake will be hydraulically dredged and pumped via pipeline to create/nourish 306 acres of marsh. Dewatering and compaction of dredged sediments should produce elevations conducive to the establishment of emergent marsh and within the intertidal range. Containment dikes will be constructed around each marsh creation cell. Where practicable, material will be borrowed from perimeter oil/gas canals. Containment dikes will be gapped at the end of construction or by TY3. Approximately 2,566 linear feet of sheet pile wall will also be installed as a containment feature. Approximately 12,479 linear feet of shoreline protection (gabion mattresses) will be installed along the lakeside boundary of the marsh creation cells on the constructed containment dikes.

The project was approved for Phase I Engineering and Design in January 2020.

The project is on Priority Project List (PPL) 29.

The Federal Sponsor is US Fish & Wildlife Service.

The Local Sponsor is CPRA.