The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council.

Wednesday, January 30, 2008
35

Monitoring a Level 5 Watershed with Very-Large Scale Aerial Imagery

Charles E. Fifield1, D. Terrance Booth2, Samuel E. Cox2, James Cagney3, and Joe Nance4. (1) Casper Field Office, USDI-BLM, 2987 Prospector Drive, Casper, WY 82604, (2) High Plains Grasslands Research Station, USDA-ARS, 8408 Hildreth Road, Cheyenne, WY 82009, (3) Wyoming State Office, USDI-BLM, 5323 Yellowstone Road, Cheyenne, WY 82003, (4) Cloudstreet Flying Services, 4623 East County Road 54, Fort Collins, CO 80524

The use of high-resolution aerial images, acquired using a sport airplane and a computer-controlled camera system, may provide land managers information that will enable them to evaluate rangeland health and monitor rangeland trend over large acreages on a landscape scale.  It may also have utility for monitoring large-scale reclamation projects.  A fifth order watershed was flown in central Wyoming in June 2007. The project consisted of 4 phases.  Phases 1 and 2 were designed to obtain multiple images that could be used to determine ground cover, species composition and canopy cover of Wyoming big sagebrush communities by ecological site.  Phase 3 was designed to evaluate channel conditions of a major drainage in the watershed and to determine the extent of the nonnative invader, tamarisk (Tamarix sp.), as a baseline for monitoring tamarisk biological control. Phase 4 was designed to monitor the success of rehabilitation of disturbed areas along a major pipeline that crosses a portion of the watershed. The survey required 15 days of which 9 days were non-flyable. Cost for pilot and airplane (including no-fly days) was $8,769. Costs include 22.5 air-time hours at $150 / hr plus charges for ground time and travel. Ground support ($40 / hr) cost $6,280 plus $1,307 travel costs, giving a total image acquisition cost of $16,356. The survey was conducted using a 2-camera system and 2 flight altitudes. Over 3,600 geocoded sample locations were photographed across the 244,000-acre survey at resolutions of 1 and 10 mm per pixel. Close to 400 sample locations were acquired in Phase 3 and 4 special flights over pipeline rights of way and riparian corridors at 2 and 20 mm per pixel. These levels of sampling, not feasible using conventional methods and staffing, now enable the application of statistical science to watershed-level range management.