ARS | Publication request: Aerial Environmental Assessment of Cottonwood Creek Watershed, Platte River Resource Area

Submitted to: Range Management Meeting Proceedings
Publication Acceptance Date: September 1, 2003
Publication Date: September 2, 2004
Citation: Booth, D.T., Cox, S.E., Whyde, D., Fifield, C., Phillips, M., Nance, J. 2004. Aerial Environmental Assessment Of Cottonwood Creek Watershed, Platte River Resource Area. Pp. 36. In: Abstract. Range Management 57th Annual Meeting Proceedings.

Technical Abstract: The Bureau of Land Management (BLM) has 162 resource management plans (RMP's) that support approved use on BLM-managed public lands, 75% need updating to ensure they are comprehensive, legally-definsible docuemnts. Updating includes environmental assessments (EA's) to determine if grazed lands conform to established standards and guidelines for healthy rangelands. We tested very-large scale aerial (VLSA) methods for a required EA on the Cottonwood Creek watershed, the creek being a perennial stream draining into the South Fork of the Powder River along the foothills of the Big Horn mountains northwest of Casper, WY. The watershed contains nearly 175,000 acres, includes all or part of 22 public grazing allotments and private pastures, and is part of the Platte River RMP administered to by the BLM's Casper Field Office. The aerial assessment produced 456 nadir photographs obtained at 0.7-mile intervals, plus 45 in a riparian survey, using an 11.1-megapixel digital color camera with a 420 mm lens. The camera was mounted in an ultra-light-type, fixed-wing airplane flown at 45 mph ground speed, 330 ft above ground level (AGL). Data were also collected using standard BLM protocols and by acquiring 59 photographs from 7 ft AGL using a camera stand and a 5-megapixel digital camera. Bare-ground and other measurements are being made from the photographs and data will be compared by collection method. Cost for obtaining the photography was about $6000 or $0.03 per acre and the data represent a permanent photographic record against which future assessments may be compared.