HR: 14:30h
AN: NB13D-05 INVITED     [Abstracts]
TI: A Multi-Scale Screening Process for Identification of Least-Disturbed Stream Sites: Finding the Best of What's Left
AU: * Lattin, P D
EM: lattin.peter@epa.gov
AF: Dynamac Corporation, 200 SW 35th St., Corvallis, OR 97333 United States
AU: McAllister, L S
EM: mcallister.lynne@epa.gov
AF: Dynamac Corporation, 200 SW 35th St., Corvallis, OR 97333 United States
AU: Ringold, P L
EM: ringold.paul@epa.gov
AF: U.S. Environmental Protection Agency NEERL-WED, 200 SW 35th St., Corvallis, OR 97333 United States
AB: We developed a multi-stage screening approach for identifying least-disturbed perennial stream sites. The approach was applied and evaluated in the Northwestern Great Plains. A GIS-based coarse screen score was used to rank 125,000 nested 1st--5th order stream networks according to disturbance. Least-disturbed candidates were drawn from 35 predefined strata during subsequent screening stages. Approximately 680 catchments were fine screened using online digital orthophotos, 132 were subsequently reviewed by local resource managers, 77 inspected during aerial and ground reconnaissance steps, and 34 finally selected as least-disturbed candidates. The EPA's EMAP probability sites, with associated watershed-level land use and stream chemistry data, were used to evaluate screening effectiveness. Coarse and fine screen disturbance scores were calculated for the evaluation sites. These scores were then divided into thirds, representing `least', `moderate', and `most' disturbed sites. Least-disturbed sites, as defined by coarse screen scores had significantly less associated agriculture and lower total nitrogen, and somewhat lower ammonium levels than most-disturbed sites. Least-disturbed sites based on fine screen scores also had significantly less associated agriculture and lower ammonium, and somewhat lower total nitrogen levels. Based on these results, the multi-stage screening approach appears to be effective for identifying least-disturbed streams within predefined strata.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly