The 3D Elevation Program in Nevada: $11.4 Million a Year in Benefits

Why elevation data

Elevation data serve forestry, wildlife management, national security, recreation and much more. In Nevada they matter most for infrastructure and construction, natural resources conservation, flood risk management, geologic resource assessment and hazard mitigation, and agriculture. Most elevation models now come from high-density lidar (light detection and ranging), and federal, state, tribal and local agencies work together to replace older, poorer data and fill gaps, aiming for consistent statewide coverage.

The national programme

The National Enhanced Elevation Assessment (NEEA; Dewberry, 2011) weighed options for data quality and how often to refresh it against cost. The best benefit-to-cost ratios came from quality level 2 lidar for the conterminous United States and quality level 5 ifsar (interferometric synthetic aperture radar) for Alaska, refreshed every 6 to 10 years. The 3D Elevation Program (3DEP), managed by the U.S. Geological Survey as the federal lead for land elevation data, chose an 8-year cycle.

3DEP aims to cover the whole country by the end of 2022, depending on funding and partners, with data more accurate and current than the National Elevation Dataset — quality level 2 or better lidar over the conterminous United States, Hawaii and the territories, and quality level 5 ifsar in Alaska, collected over eight years and made public. Conservatively it could bring $1.2 billion a year in new benefits, and potentially $13 billion a year, through better government services, fewer crop and flood losses, more efficient vehicle routing and more. A funded national programme brings economies of scale (larger collection areas cut costs by 25 percent), a systematic plan that lowers the cost of "buying up" to higher quality, consistency across state and watershed lines, more federal money so partners pay less, and ready contracts and specifications.

Benefits for Nevada

NEEA respondents in Nevada estimated at least $11.4 million a year in new benefits, against a cost of about $37 million — a payback of 3.2 years and a benefit-to-cost ratio of 2.5 to 1 over eight years. Not every benefit was given a dollar value, so the real total is probably much higher. About 82 percent of the identified needs fall in infrastructure and construction and natural resources conservation.

Closer coordination between 3DEP and organisations in the state could capture more than these conservative figures.

How the data would be used

• Conservation. Better data would help governments carry out habitat easements and restoration, wetland restoration, grade stabilisation, dam safety, pipeline routing, wildland fire modelling, protection of cultural resources and vegetation surveys, at significant savings to the public.
• Geology and faults. The Nevada Bureau of Mines and Geology and the Nevada Division of Minerals use elevation data for geologic mapping, and lidar sharpens the mapping of bedrock and surface geology that underpins assessments of resources and hazards. Nevada is the third most seismically active state, yet its active faults are not all identified; lidar is ideal for finding young faults. In Dixie Valley it revealed scarps, unnoticed before lidar, that probably formed in the 1954 earthquake. Mapping geothermal energy and mineral deposits is also faster and more accurate with lidar.
• Floods. Flash floods from summer monsoon thunderstorms are a serious hazard in the state's cities and have cost natural resources, lives and property in recent decades. Combining aerial imagery and lidar would allow detailed flood-hazard analysis and help reduce future damage.

Next steps

Reaching national coverage in eight years depends on more partnerships among federal, state, tribal and local governments; partnerships that collect data to 3DEP specifications over larger areas; more awareness of the programme's benefits and goals; and support from government and other stakeholders.

Sources

• Carswell, W.J., Jr., 2015, The 3D Elevation Program — Summary for Nevada (ver. 1.1): U.S. Geological Survey Fact Sheet 2015–3028. https://pubs.usgs.gov/publication/fs20153028
• Map: U.S. Geological Survey, from the U.S. Interagency Elevation Inventory (March 2015). The fact sheet's lidar image of the Dixie Valley fault, courtesy of the Nevada Bureau of Mines and Geology, is left out.
• Rewritten in hubnx's own words.