Lidar in Tennessee: How the 3D Elevation Program Supports the State's Economy

Tennessee covers about 42,100 square miles across six physiographic regions: the Blue Ridge, Valley and Ridge, Appalachian Plateaus, Highland Rim, Nashville Basin and Gulf Coastal Plains. Current elevation data underpin economic development, infrastructure and construction, agriculture and precision farming, forestry, conservation, flood risk and emergency management, and urban and regional planning. The state also has frequent landslides on major roads, and high-resolution elevation data help find the slopes prone to them.

Those uses depend on lidar (light detection and ranging), which builds a detailed 3D model of the ground and everything on it.

The 3D Elevation Program

The 3D Elevation Program (3DEP) is run by the U.S. Geological Survey (USGS) with Federal, State, Tribal, U.S. territorial and local partners. Its goal is the first-ever national baseline of consistent, high-resolution elevation data — bare-earth digital elevation models and 3D point clouds — from lidar (and from IfSAR, interferometric synthetic aperture radar, in Alaska).

Baseline 3DEP data are quality level 2 or better, with 1-meter or better elevation models and point clouds, and must meet the Lidar Base Specification version 1.2 or newer.

Status of 3D Elevation Program baseline lidar data in Tennessee as of January 2025. Map: U.S. Geological Survey.

RMSEz is the root mean square error in elevation. QL0 specifications from Heidemann (2012); QL1 and QL2 from Sugarbaker and others (2014).

The data go into The National Map, free and without restrictions, through the National Map downloader; the Lidar Explorer shows what's available.

Tennessee: 100% done

Quality level 2 lidar now covers all of Tennessee — the result of close coordination between governments:

In 2022, quality level 1 lidar was flown over Davidson County (the Nashville area) to update the QL2 data there. The long-term plan is to bring the whole state up to QL1 as part of the USGS 3D Hydrography Program. (QL0 and QL1 cost extra.)

What it's worth

The National Enhanced Elevation Assessment (Dewberry, 2012) conservatively estimated that lidar would bring Tennessee at least $6.32 million a year in new benefits. Its top 10 business uses:

Where it helps

Farming. Tennessee's 2020 cash crop receipts were $2.35 billion (Tennessee Department of Agriculture). A more accurate picture of the terrain sharpens precision farming — better yields, less soil degradation, less groundwater use and less chemical runoff — and a better return for farmers.

Conservation. With QL2 statewide, public and private groups can use lidar for planning and site engineering, cutting fieldwork for conservation ponds, grassed waterways, pipelines and terracing, calculating runoff accurately, finding drained historical wetlands, and restoring wetlands.

Flood risk. Accurate statewide elevation data cut the cost and time of collecting data on site for flood risk projects that protect lives and property, and improve the analyses; the savings can go to other flood projects.

Geology and hazards. The Tennessee Department of Environment and Conservation uses elevation data for detailed geologic mapping, analysis of structures and stratigraphy, and mineral assessment — informing policy and supporting the state's non-fuel mineral industry, whose production totaled $1.46 billion in 2018. Dense vegetation can hide hazards; bare-earth lidar models can:

1. locate abandoned mine lands, landscape changes from oil and gas drilling, and active or old landslides that could move again;
2. detect sinkholes in karst areas that earlier elevation mapping missed.

That supports public and environmental safety and helps industry pick sites.

Why a national program

• Economies of scale from buying data for larger areas.
• Predictable, flexible federal investment that can cut costs and help planning.
• Consistent national coverage for work that crosses project, jurisdictional and watershed boundaries.
• Simpler buying: contracts, project management, quality assurance and published specifications.
• National benefits of $690 million a year, conservatively, and potentially $13 billion a year more through uses across the economy (Dewberry, 2012).

How to take part

Federal, State, Tribal, U.S. territorial and local governments and private-sector partners can join — and can buy even higher-quality data. Partners may put money into USGS-managed projects or receive cooperative funds to run their own; an annual Data Collaboration Announcement sets up the agreements. Existing data that meet 3DEP requirements can also be contributed. More: 3DEP — collaborate.

Sources

Based on George Heleine, "The 3D Elevation Program—Supporting Tennessee's economy," U.S. Geological Survey Fact Sheet 2025–3037, USGS; a work of the United States government in the public domain. It cites Dewberry (2012), National Enhanced Elevation Assessment final report; Heidemann (2012), Lidar base specification; Sugarbaker and others (2014), The 3D Elevation Program initiative—A call for action; Tennessee Department of Agriculture (2021), Biennial report 2019–2020; and Tennessee Department of Environment and Conservation (2020), Tennessee's mineral industry. The map is reproduced from the fact sheet.