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The first US National Coastal Condition Assessment survey in the Great Lakes: Development of the GIS frame and exploration of spatial variation in nearshore water quality results
Citation:
Kelly, J., P. Yurista, M. Starry, J. Scharold, W. Bartsch, AND A. Cotter. The first US National Coastal Condition Assessment survey in the Great Lakes: Development of the GIS frame and exploration of spatial variation in nearshore water quality results. JOURNAL OF GREAT LAKES RESEARCH. International Association for Great Lakes Research, Ann Arbor, MI, 41:1060-1074, (2015).
Impact/Purpose:
A comprehensive approach to assess conditions in the Great Lakes nearshore zone has been lacking for decades. We had the opportunity to conduct a pilot survey in Lake Erie (45 sites) in summer 2009 and to develop a full survey across the 5 lakes (~400 sites) as part of the US National Coastal Condition Assessment (NCCA) in summer 2010. The general approach provides unbiased, statistically based estimates with defined uncertainty bounds. This paper reports on the development and nature of the frame and sample populations, as well as an extensive, but still preliminary, analysis of water quality results in both 2009 and 2010. Spatial variability in water quality was analyzed with respect to the nearshore sample population (!225 sites) representing the whole US region of the Great Lakes, defined by automated GIS procedures with criteria to include waters to 30 m depth and no further than 5 km from shore. A separate, sub-population of the nearshore (~150 sites) was defined to represent small to medium embayments, using both size and geometric criteria to define indentations along the mainland’s shoreline. We focus on Total Phosphorus (TP), among other parameters, to provide example results at different scales and for the two resource populations. Statistical comparisons across resources, regression modeling, and hierarchical partitioning were all conducted. Overall, the analyses firmly identified two major factors driving spatial variability: water column depth and a watershed disturbance metric to represent
Description:
A comprehensive approach to assess conditions in the Great Lakes nearshore zone has been lacking for decades. We had the opportunity to conduct a pilot survey in Lake Erie (45 sites) in summer 2009 and to develop a full survey across the 5 lakes (~400 sites) as part of the US National Coastal Condition Assessment (NCCA) in summer 2010. The general approach provides unbiased, statistically based estimates with defined uncertainty bounds. This paper reports on the development and nature of the frame and sample populations, as well as an extensive, but still preliminary, analysis of water quality results in both 2009 and 2010. Spatial variability in water quality was analyzed with respect to the nearshore sample population (!225 sites) representing the whole US region of the Great Lakes, defined by automated GIS procedures with criteria to include waters to 30 m depth and no further than 5 km from shore. A separate, sub-population of the nearshore (~150 sites) was defined to represent small to medium embayments, using both size and geometric criteria to define indentations along the mainland’s shoreline. We focus on Total Phosphorus (TP), among other parameters, to provide example results at different scales and for the two resource populations. Statistical comparisons across resources, regression modeling, and hierarchical partitioning were all conducted. Overall, the analyses firmly identified two major factors driving spatial variability: water column depth and a watershed disturbance metric to represent
