Louisiana’s Defense Systems: Wetlands and the Case of the Great Wall of Louisiana

In 2013 the US Army Corps of Engineers (USACE) completed construction of the “Inner Harbor Navigation Canal Lake Borgne Surge Barrier”. The project is funded through the Hurricane and Storm Damage Risk Reduction System (HSDRRS) for southeast Louisiana and considered to be the largest civil works project in corps history. The barrier was built to combat storm surge heights like those observed during Hurricane Katrina in 2005. More commonly known as the Great Wall of Louisiana, engineering innovations like a 1000 foot trestle allowed the project to be completed in about 3 years’ time instead of an estimated 20. The barrier wall is 1.8 miles in distance, 26 feet tall, and at an estimated construction cost of $1.1 billion federally funded dollars.

Louisiana contains 40 percent of the continental United States’ wetland acreage. Coastal wetlands can protect against storm surge energy and flooding by marsh grasses, trees, and soil working as as system. However Louisiana continues to lose wetlands due to problems like subsidence, sea-level rise, sediment deprivation, oil and gas development, and climate change. With an extreme need of wetland preservation, coastal agencies like CWPPRA and USACE are strategizing to combat these issues.

USACE is one of the five managing agencies of the Coastal Wetlands Planning, Protection, and Restoration Act. CWPPRA’s mission is to fund, plan, design, and construct restoration projects in coastal Louisiana at a large and fast pace scale. CWPPRA projects are synergistically funded through partner programs, such as the Inner Harbor Navigation Canal Borgne Surge Barrier to protect, preserve, and restore Louisiana’s coast.

wall_pic

Featured Image Source: https://bit.ly/2MjEIyA

Wetland Vegetation

Wetland ecologists often refer to wetland vegetation as the foundation of coastal restoration. Native plants and vegetative plantings both provide significant benefits to wetlands. Wetland plants build and stabilize soil, create habitat, purify water, and shield infrastructure. These plants tend to accumulate the thick mud of marshes which prevents the soil from washing away. Animals that live in wetlands depend on plants or plant-eating animals for their food supply. Without wetland vegetation, the supply chain would self-destruct. By absorbing nutrients and chemicals from the water and sediment, plants reduce toxins and groundwater contamination. Wetland vegetation is key to preventing shoreline erosion and reducing storm surge which affects the coastal infrastructure.

The Coastal Wetlands Planning, Protection and Restoration Act funds a variety of wetland enhancement projects, such as vegetative planting. Vegetative planting is the process of planting by hand or aerial seeding to shore up eroding banks and jump-start plant colonization.

You can read more about CWPPRA Projects that use the vegetative planting restoration technique by clicking here.