作者: David V. Peck , Anthony R. Olsen , Marc H. Weber , Steven G. Paulsen , Carol Peterson
DOI: 10.1899/11-075.1
关键词: Level iii 、 Sampling (statistics) 、 Physical geography 、 National Hydrography Dataset 、 Environmental protection 、 Aquatic resources 、 Salt lake 、 Geography 、 Target population 、 Survey research 、 Sampling frame
摘要: AbstractThe US Environmental Protection Agency (USEPA) conducted a National Lakes Assessment (NLA) in the conterminous USA 2007 as part of national assessment aquatic resources. The EPA used Hydrography Dataset (NHD) basis for sample frame NLA. target population was all lakes >4 ha, excluding Laurentian Great and Salt Lake. An unequal probability survey design to select 4472 candidate potential sampling. selection depended on 5 lake area classes 9 aggregated Omernik level III ecoregions. In all, 2034 were evaluated inclusion population, 1309 (representing ∼68,000 frame) met criteria. A total 1028 (of 1309) sampled represented ∼50,000 lakes. remaining (231, representing ∼18,000 lakes) could not be because access denial or physical inaccessibility. included natural (41 ± 2% [SE]) and...