Few places need precise elevation data more than Louisiana, where much of the land was built by the Mississippi River Delta and is sinking while the sea rises. High-resolution, three-dimensional elevation data from lidar (light detection and ranging), which gives a highly detailed 3D model of the ground and what stands on it, help the state model floods, protect public safety, and fight land subsidence and sea-level rise. The same data serve construction, coastal management, wildlife, farming, planning, water supply and conservation.
The 3D Elevation Program
The 3D Elevation Program (3DEP), managed by the U.S. Geological Survey with federal, state, tribal, territorial and local partners, aims to give the whole nation its first consistent, high-resolution elevation baseline — bare-earth elevation models and 3D point clouds (with radar data in Alaska). Its baseline lidar must meet quality level 2 or better:
| Quality level | Vertical accuracy (RMSE) | Pulse density |
|---|---|---|
| QL0 (highest) | 5 cm or better | 8 or more per square meter |
| QL1 | 10 cm or better | 8 or more per square meter |
| QL2 | 10 cm or better | 2 or more per square meter |
Status of 3DEP baseline lidar data in Louisiana, November 2024. Image from the USGS fact sheet.
By November 2024, baseline data were available or in progress for 95% of the state. A national assessment conservatively estimated the data would bring Louisiana at least $6.96 million a year in new benefits, led by:
| Use | Annual benefit |
|---|---|
| Flood risk management | $1.85 million |
| Natural resources conservation | $1.83 million |
| Agriculture and precision farming | $1.24 million |
| Infrastructure and construction management | $0.80 million |
| Water supply and quality | $0.27 million |
Floods
Historic flooding in 2016 killed 13 people and damaged about 158,000 homes, prompting the state to rethink how it prepares for increasingly frequent floods. The Louisiana Watershed Initiative, announced in 2018, is improving flood risk management, and the state is pursuing statewide quality level 1 lidar with its partners.
A shifting coast
The delta constantly reshapes the land and the water’s edge, complicating infrastructure, safety and an economy that serves the nation through ports, rail and highway links, energy and seafood. Louisiana’s Comprehensive Master Plan for a Sustainable Coast includes major engineering projects to slow shoreline loss, and high-resolution elevation data are essential for its flood modeling, restoration and land-change studies.
Roads and infrastructure
The Louisiana Department of Transportation and Development requires quality level 1 lidar for transportation design, flood modeling, emergency response, mapping and protecting infrastructure. Its Statewide Topographic Mapping Program and open data portal share geospatial data among agencies and industry, supporting site selection, terrain modeling, floodplain mapping and drainage work.
Sea-level rise
On the extremely low, flat northern Gulf coast, elevation is the main factor deciding which places will flood as the sea rises. Quality level 1 data can distinguish the small differences in height that can make a location safe to use — or uninhabitable.
Sources
Based on "The 3D Elevation Program—Supporting Louisiana’s economy," U.S. Geological Survey Fact Sheet 2025–3034; a work of the United States government in the public domain.
Licence: CC0 1.0 (public domain) · Adapted from pubs.usgs.gov
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