Lidar Elevation Data for Kansas: The 3D Elevation Program

Publicly available lidar in Kansas, October 2014, from the U.S. Interagency Elevation Inventory (updated yearly). Quality level 2 or better meets 3DEP's requirements; the fact sheet's legend leaves the dark-blue swatch unlabelled. USGS.

Why elevation data matters

Elevation data serve forestry, wildlife and habitat management, national security, recreation and much else. In Kansas they matter most for agriculture and precision farming, natural resources conservation, flood risk management, infrastructure and construction, and geologic resources and hazards. 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 76% of the identified needs fall in agriculture and conservation. Not every benefit had a dollar value, so the true total is likely much higher — and closer coordination between 3DEP and Kansas's public and private organisations could reach beyond these conservative figures.

How lidar helps Kansas

Farming. About 90% of Kansas's land is used for agriculture. More accurate terrain can greatly improve precision farming — raising yields, preventing soil loss and cutting chemical runoff — so farmers get a better return.

Streams and floods. Lidar terrain can update The National Map's National Hydrography Dataset (NHD) and feeds cheaper, more accurate hydrologic and hydraulic flood studies; the design of bridges and culverts for big storms; and retention-dam design, dam-breach studies and stormwater engineering. It also helps find vulnerable properties in floodplains, supporting better floodplain decisions and showing the public its real flood risk, and dynamic 3D models add detail on what a flood could do.

A Kansas stream channel as mapped in the NHD, drawn on a recent aerial image (A): dense vegetation hides where the channel really runs. A bare-earth elevation model made from lidar (B) shows its true position, and a place where runoff could be stored temporarily (blue added for emphasis). The USGS is using such models to update the NHD. USGS images.

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: 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 Kansas," U.S. Geological Survey Fact Sheet 2014–3106 (November 2014); a work of the United States government in the public domain. The map, figure and tables are taken from the fact sheet's PDF. Benefit figures come from Dewberry's National Enhanced Elevation Assessment (2011, revised 2012).