Lidar Elevation Data for West Virginia: The 3D Elevation Program

Publicly available lidar in West Virginia, June 2014. No data meeting 3DEP's quality level 2 standard were available. USGS, from the U.S. Interagency Elevation Inventory.

Why elevation data matters

Elevation data underpin everything from forest and wildlife management to national security and recreation. In West Virginia they are critical for natural resources conservation, flood risk management, forest management, infrastructure and construction, and agriculture.

Today, high-density lidar (light detection and ranging) is the main source of elevation models. Federal, state, tribal and local agencies work together to replace older, lower-quality data and to fill gaps where no public data exist, with the shared aim of consistent statewide coverage.

What it's worth

• Benefits: at least $2.6 million a year in new benefits to the state (conservative).
• Cost: about $8.1 million.
• Payback: 3.1 years; benefit/cost ratio 2.6 to 1 over 8 years.
• About 72% of the identified needs fall in conservation and flood risk management.

Because not every benefit was given a dollar value, the true total is likely much higher.

How lidar helps West Virginia

Floods. Lidar gives better, cheaper terrain for flood studies and hydrologic modeling; for designing bridges and culverts to carry runoff from big storms; and for dam design, dam-breach studies and stormwater engineering. It also pinpoints vulnerable properties in floodplains, helping floodplain decisions and showing the public their true flood risk.

Geologic hazards. Landslides, active faults, abandoned mines and sinkholes in karst can hide under forest. Bare-earth lidar strips away the vegetation so they can be found and mapped systematically — supporting risk assessment, hazard mitigation, land-use planning and site selection for industry.

Bare-earth elevation models and slope maps also reveal landforms made by mining, roads and railroads. The biggest are unreclaimed strip-mine benches: their near-vertical highwalls above and loose fill slopes below are potentially unstable, and they commonly contribute to landslides in the New River Gorge National River in southern West Virginia.

About 3DEP

The National Enhanced Elevation Assessment (Dewberry, 2011) weighed options for data quality and how often to refresh it. The best return came 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 runs 3DEP as the federal lead for land elevation data.

• Goal: complete national coverage by the end of 2022, depending on funding and partners — more accurate and current than the National Elevation Dataset.
• Value: conservatively $1.2 billion a year in new benefits nationally, with the potential for $13 billion a year — better government services, fewer crop and flood losses, more efficient vehicle routing and more.
• Why a national program: buying larger areas cuts costs by 25%; buying at higher quality avoids paying to "buy up" later; consistent data work across state and watershed lines; more federal money reduces what states and localities pay; and ready contracts and specifications simplify buying.

Sources

Based on William J. Carswell, Jr., "The 3D Elevation Program: summary for West Virginia," U.S. Geological Survey Fact Sheet 2015–3017 (2015); a work of the United States government in the public domain. The map and tables are taken from the fact sheet's PDF; its landslide image, credited to a West Virginia University geology department, is not reproduced. The benefit figures come from Dewberry's National Enhanced Elevation Assessment (2011, revised 2012).