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National Aquatic Resource Surveys: Use of Geospatial data in their design and spatial prediction at non-monitored locations
Citation:
Olsen, Tony, Tom Kincaid, M. Weber, R. Hill, AND S. Leibowitz. National Aquatic Resource Surveys: Use of Geospatial data in their design and spatial prediction at non-monitored locations. JSM, Seattle, WA, August 08 - 13, 2015.
Impact/Purpose:
The National Aquatic Resource Surveys (NARS) are four surveys conducted by the U.S. Environmental Protection Agency working in collaboration with states, tribal nations and other federal agencies. The surveys are conducted for lakes and reservoirs, streams, estuaries and intracoastal waterways, and wetlands. Geospatial information is essential component of NARS survey designs and analyses. Based on spatial survey designs, NARS studies provide nationally consistent and scientifically-defensible assessments of the nation’s waters and can be used to track changes over time. While the surveys provide estimates at national and regional scales, information for managing aquatic resources is needed at local scale. This research is developing an approach to predict stream condition at non-monitored locations. Preliminary random forest models have been developed to predict stream condition for all ~5.4 million km of streams in the 48 contiguous states.
Description:
The National Aquatic Resource Surveys (NARS) are four surveys conducted by the U.S. Environmental Protection Agency working in collaboration with states, tribal nations and other federal agencies. The surveys are conducted for lakes and reservoirs, streams, estuaries and intracoastal waterways, and wetlands. Fundamental to the survey design and analysis is the dependence on geospatial data from the National Hydrography Dataset (NHD) as a basis for the sample frame for three of the four surveys. For each survey, the R package “spsurvey” is used to select a spatially-representative sample of sites from this geospatial sample frame. Sample site selection is based on a generalized random tessellation stratified design (GRTS). Geospatial information is also used in the local neighborhood variance estimator that was developed for GRTS designs, which has been shown to provide better coverage probability than the Horvitz-Thompson estimator. Based on spatial survey designs, NARS studies provide nationally consistent and scientifically-defensible assessments of the nation’s waters and can be used to track changes over time. We also are developing an approach to predict stream condition at non-monitored locations. Preliminary random forest models have been developed to predict stream condition for all ~5.4 million km of streams in the 48 contiguous states.The National Aquatic Resource Surveys (NARS) are four surveys conducted by the U.S. Environmental Protection Agency working in collaboration with states, tribal nations and other federal agencies. The surveys are conducted for lakes and reservoirs, streams, estuaries and intracoastal waterways, and wetlands. Fundamental to the survey design and analysis is the dependence on geospatial data from the National Hydrography Dataset (NHD) as a basis for the sample frame for three of the four surveys. For each survey, the R package “spsurvey” is used to select a spatially-representative sample of sites from this geospatial sample frame. Sample site selection is based on a generalized random tessellation stratified design (GRTS). Geospatial information is also used in the local neighborhood variance estimator that was developed for GRTS designs, which has been shown to provide better coverage probability than the Horvitz-Thompson estimator. Based on spatial survey designs, NARS studies provide nationally consistent and scientifically-defensible assessments of the nation’s waters and can be used to track changes over time. We also are developing an approach to predict stream condition at non-monitored locations. Preliminary random forest models have been developed to predict stream condition for all ~5.4 million km of streams in the 48 contiguous states.The National Aquatic Resource Surveys (NARS) are four surveys conducted by the U.S. Environmental Protection Agency working in collaboration with states, tribal nations and other federal agencies. The surveys are conducted for lakes and reservoirs, streams, estuaries and intracoastal waterways, and wetlands. Fundamental to the survey design and analysis is the dependence on geospatial data from the National Hydrography Dataset (NHD) as a basis for the sample frame for three of the four surveys. For each survey, the R package “spsurvey” is used to select a spatially-representative sample of sites from this geospatial sample frame. Sample site selection is based on a generalized random tessellation stratified design (GRTS). Geospatial information is also used in the local neighborhood variance estimator that was developed for GRTS designs, which has been shown to provide better coverage probability than the Horvitz-Thompson estimator. Based on spatial survey designs, NARS studies provide nationally consistent and scientifically-defensible assessments of the nation’s waters and can be used to track changes over time. We also are developing an approach to predict stream condition at non-monitored locations.