The 3D Elevation Program in Iowa: $18.7 Million a Year in Benefits

Why elevation data

Elevation data serve forestry, wildlife management, national security, recreation and much more. In Iowa they matter most for agriculture and precision farming, infrastructure and construction, natural resources conservation, flood risk management, and water supply and quality. 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 Iowa

As of October 2014, no publicly available lidar in Iowa met 3DEP's quality level 2 standard; the state was covered at quality level 3.

NEEA respondents in Iowa estimated at least $18.7 million a year in new benefits, against a cost of about $19 million — a payback of one year and a benefit-to-cost ratio of 8.0 to 1 over eight years. Not every benefit was given a dollar value, so the real total is probably much higher. About 90 percent of the identified needs fall in agriculture and precision farming, 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

• Farming. About 85 percent of Iowa's land is farmed. Better elevation data show the terrain far more accurately and can transform precision farming — GPS-guided equipment that sets seed and chemical rates more exactly — raising yields, preventing soil degradation and cutting chemical runoff, so farmers get more from their investment.
• Conservation. Governments could carry out conservation practices more effectively and cheaply; with lidar nationwide, organisations would use it more for planning and engineering and do less field work on grade stabilisation, ponds, grassed waterways, terracing and wetland restoration.

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 Iowa (ver. 1.1): U.S. Geological Survey Fact Sheet 2015–3018. https://pubs.usgs.gov/publication/fs20153018
• Map: U.S. Geological Survey, from the U.S. Interagency Elevation Inventory (October 2014). The fact sheet's tractor photograph, courtesy of the J.R. Simplot Company, is left out.
• Rewritten in hubnx's own words.