Lidar Elevation Data for Mississippi: The 3D Elevation Program

Publicly available lidar in Mississippi, June 2014, from the U.S. Interagency Elevation Inventory (updated yearly). Quality level 2 or better meets 3DEP's requirements. USGS.

Why elevation data matters

Elevation data serve forestry, wildlife and habitat management, national security, recreation and much else. In Mississippi they matter most for infrastructure and construction, flood risk management, agriculture and precision farming, natural resources conservation, forest resources and water supply and quality. High-density lidar is now the main source of elevation models. Federal, state, tribal and local agencies work together to replace older, lower-quality data and fill gaps, aiming for consistent statewide coverage.

By the numbers

About 91% of the identified needs fall in the leading uses, starting with infrastructure and construction and flood risk management. Not every benefit had a dollar value, so the true total is likely much higher.

How lidar helps Mississippi

Roads. A statewide lidar dataset would improve assessments of existing roads with fewer site visits, help identify where safety projects are needed, give more detailed environmental information across large project areas, and help judge how proposed construction would affect habitat.

Floods and dams. More accurate statewide elevation data would cut field data-collection costs and time on parts of flood risk projects, and improve the quality of the analyses. Projects would finish faster and cheaper, freeing money for other priority flood work. The Mississippi Department of Environmental Quality's Dam Safety Division, for example, uses lidar to draw cross sections and map inundation areas for dam-breach models and dam hazard assessments, reducing time-consuming field surveys.

About 3DEP

The National Enhanced Elevation Assessment (Dewberry, 2011) found the best return from quality level 2 lidar for the conterminous United States and quality level 5 radar (ifsar) for Alaska, refreshed every 6 to 10 years; 3DEP chose an 8-year cycle. The USGS — the federal lead agency for land elevation data — runs it, and its data improve on the older National Elevation Dataset.

• Goal: operational by January 2015 and complete national coverage by the end of 2022, depending on funding and partners; lidar at quality level 2 or better over the conterminous states, Hawaii and the territories, ifsar in Alaska, all made public.
• Value: conservatively $1.2 billion a year nationally, with the potential for $13 billion a year — from better government services, smaller crop and flood losses, more efficient vehicle routing and more.
• Why a national program: larger purchases cut costs by 25%; buying high quality once avoids paying to "buy up" later; consistent data across state and watershed lines; more federal money reduces state and local shares; and ready contracts and specifications simplify buying.
• What it depends on: more partnerships among federal, state, tribal and local governments; partners buying to the program's specifications over larger areas; wider awareness of its benefits; and support from government and other stakeholders.

Sources

Based on William J. Carswell, Jr., "The 3D Elevation Program—Summary for Mississippi," U.S. Geological Survey Fact Sheet 2014–3057 (August 2014); a work of the United States government in the public domain. The map and tables are taken from the fact sheet's PDF; its dam-breach model image, made by the Mississippi Department of Environmental Quality on a commercial basemap and used with permission, is left out. Benefit figures come from Dewberry's National Enhanced Elevation Assessment (2011, revised 2012).