Louisiana Coastal Protection and Restoration Authority (CPRA)

Louisiana Watershed Initiative

After the 2016 floods led to major disaster declarations across 56 parishes, Louisiana’s state government decided to fundamentally change its approach to addressing flood risk.

The Challenge

Rather than making decisions based on city or parish boundaries, Louisiana recognized that floods are not limited by these artificial lines. As a result, the state is using new watershed science and watershed-based planning to improve flood risk decision-making across jurisdictions and improve flood mitigation statewide. To implement holistic approaches statewide, the state established the Louisiana Watershed Initiative (LWI) to improve the way residents and governments understand, address, and respond to flood risk.

The Approach

LWI, managed by the state’s Office of Community Development (OCD), addresses watershed projects and programs at the local, regional, and state levels. This will be done through watershed monitoring, mapping, and modeling as well as policy and planning activities required to successfully implement these programs. The Institute is providing programmatic and technical support across a range of LWI activities, such as the creation of graduated flood hazard maps for the entire state, including many areas that have never been mapped.

In addition, a large portion of the Louisiana population resides in areas that experience flooding from extreme rainfall and coastal surges, often over concurrent tidal cycles, in periods in which wet soils impair infiltration. The Institute is leading the development of a modeling methodology and guidance for these compound flood areas, referred to as flood transition zones. The Institute is partnering with academic researchers at Louisiana State University, the University of Iowa, and Purdue University to perform a coincident analysis and test numerical model setups. These efforts will inform the development of a recurrence analysis framework used in the flood transition zones while also remaining consistent with the Louisiana Coastal Master Plan.

The Institute is supporting OCD in aligning the modeling program with the larger Watershed Initiative by managing the Data and Modeling Technical Advisory Group, engaging with local government stakeholders on modeling and other decision support tool use for watershed management projects, ensuring that the models meet the highest standards by serving on the Technical Delivery and Quality (TDQ) team, developing data management plan templates and procedures such that data can be consistently stored and accessed by stakeholders over the long-term and developing state and regional policy recommendations and supporting legislation.