README: Mapping Flood Impacts on Buildings in a Coastal Community

This documentation accompanies the GIS layers and data analysis outputs derived from the study on flood risk and potential solutions within a flood-prone community in South Louisiana, USA. The work is part of the research publication:

Habib, E. H., Miles, B., Skilton, L., ElSaadani, M., Osland, A. C., Willis, E., ... & Barnes, S. R. Anchoring Tools to Communities: Insights into Perceptions of Flood Informational Tools from a Flood-Prone Community in Louisiana, USA. Frontiers in Water, 5, 1087076.

The analysis leverages the Version 1 (V1) National Structure Inventory dataset in conjunction with the 500-year flood inundation map for Lafayette Parish. The objective was to quantify and analyze the damage and loss to buildings at both an individual and census block level due to potential flood scenarios. To calculate the potential damage, we utilized HAZUS, a nationally standardized methodology developed by the Federal Emergency Management Agency (FEMA) for estimating potential losses from disasters. HAZUS applies scientific and engineering principles to assess physical damage, economic losses, and social impacts of disasters.

For detailed information about HAZUS and its applications, please visit FEMA's official website or directly access the HAZUS page by navigating to https://www.fema.gov/flood-maps/tools-resources/flood-map-products/hazus.

The resulting GIS layers represent a critical component of the spatial analysis, offering detailed insights into the spatial distribution of flood risk and the potential economic impact on the community's infrastructure. This documentation aims to provide future users with a comprehensive understanding of each GIS layer. Further details on the methodology behind each layer's production are provided in the sections below.

Lafayette Parish Damage Loss Analysis

This analysis utilizes the 500-year flood inundation map and the Version 1 National Structure Inventory dataset to assess damage loss within Lafayette Parish. The study is organized into two primary subdirectories, reflecting the level of detail in the analysis:

Census_block:

• damage_number: Number of buildings impacted by the 500-year flood, aggregated per census block.
• damage_num_nonres: Number of non-residential buildings impacted by the 500-year flood, per census block.
• damage_num_res: Number of residential buildings impacted by the 500-year flood, per census block.
• damage_val: Percent damage of structure value, aggregated over the census block.
• damage_val_nonres: Percent value damage of non-residential buildings, per census block.
• damage_val_res: Percent value damage of residential buildings, per census block.

individual_loss:

• loss_of_flooded_structures: Percent loss per individual structure caused by the 500-year flood.

Ille des Cannes Watershed Analysis

This section of our analysis focuses on the flood damage loss over the watershed scale of Coulee Ile des Cannes in Lafayette Parish. Utilizing 500-year flood inundation map and the Version 1 National Structure Inventory dataset, the analysis provides an in-depth look at the potential impacts of flooding within this specific watershed.

Layers:

500 Year Flood Depth: Spatial distribution of flood depths (inundation map) across the watershed for a 500-year flood event.

Basin_Outline: The geographical boundary of the Coulee Ile des Cannes watershed.

prcnt_bldng_loss: Percentage of loss in value for each building within the watershed.