The Great Lakes Hydrography Dataset: Consistent, Binational Watersheds for the Laurentian Great Lakes Basin

Ecosystem‐based management of the Laurentian Great Lakes, which spans both the United States and Canada, is hampered by the lack of consistent binational watersheds for the entire Basin. Using comparable data sources and consistent methods, we developed spatially equivalent watershed boundaries for the binational extent of the Basin to create the Great Lakes Hydrography Dataset (GLHD). The GLHD consists of 5,589 watersheds for the entire Basin, covering a total area of approximately 547,967 km2, or about twice the 247,003 km2 surface water area of the Great Lakes. The GLHD improves upon existing watershed efforts by delineating watersheds for the entire Basin using consistent methods; enhancing the precision of watershed delineation using recently developed flow direction grids that have been hydrologically enforced and vetted by provincial and federal water resource agencies; and increasing the accuracy of watershed boundaries by enforcing embayments, delineating watersheds on islands, and delineating watersheds for all tributaries draining to connecting channels. In addition, the GLHD is packaged in a publically available geodatabase that includes synthetic stream networks, reach catchments, watershed boundaries, a broad set of attribute data for each tributary, and metadata documenting methodology. The GLHD provides a common set of watersheds and associated hydrography data for the Basin that will enhance binational efforts to protect and restore the Great Lakes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134077/1/jawr12435_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134077/2/jawr12435.pd

High-resolution assessment and visualization of environmental stressors in the Lake Superior basin

Quantifying gradients of anthropogenic stress can inform the development of sample designs, provide an important covariate in modeling relationships of response variables, identify reference and highly-disturbed sites, and provide a baseline and guidance to restoration and remediation efforts. We describe development of SumRel, a composite index of anthropogenic stress, for the U.S. and Canadian Lake Superior basin. Key elements of the project include development of high-resolution watersheds throughout the basin, summarization of the major point and non-point stressors within these watersheds, and creation of tools for scaling the watersheds and stressor summaries. SumRel was calculated at two spatial scales: for high resolution subcatchments within the Lake Superior basin (mean watershed area = 93 ha) and for coastal watersheds of Lake Superior. An assessment of subcatchments within Minnesota's St. Louis River watershed showed a correlation between the degree of disturbance, as indicated by SumRel, and impaired water quality, as evidenced by in-stream conductivity. These data and tools allow identification and visualization of reference and highly-disturbed sites at multiple spatial scales, providing decision support for individual agency and binational monitoring, assessment and restoration initiatives across the Lake Superior basin.</jats:p

Coastal Geomorphic and Lake Variability in the Laurentian Great Lakes: Implications for a Diatom-based Monitoring Tool

ABSTRACT. In an evaluation of diatoms as indicators of human disturbance in coastal ecosystems of the Laurentian Great Lakes, we characterized assemblage specificity to lake and habitat type to identify non-anthropogenic factors influencing indicator models. Surface sediment assemblages and environmen-tal variables were collected along the U.S. coastline at 191 sample sites, which were classified by lake and geomorphic type: high-energy (HE), embayment (EB), coastal wetland (CW), riverine wetland (RW), protected wetland (PW), and open water (OP). Diatom inferred (DI) total phosphorus (TP) transfer func-tions (models) were developed for each lake and geomorphic type. Robust models included: the overall model (RMSEP; r2jack = 0.65; RMSEP = 0.005), Lake Superior (r2jack = 0.73; RMSEP = 0.003), Lake Ontario (r2jack = 0.73; RMSEP = 0.007), PW (r2jack = 0.64; RMSEP = 0.003), and EB (r2jack = 0.64; RMSEP = 0.007). Weaker models, indicating poorer diatom-TP relationships, included: RW (r2jack = 0.03; RMSEP = 0.005), OP (r2jack = 0.15; RMSEP = 0.059), and Lake Michigan (r2jack = 0.38; RMSEP = 0.006). DI TP data were regressed against landscape characteristics to quantify the relationships to adjacent watershed stressors. RW data were further scrutinized as a case study to investigate the suitabil-ity of diatom-based approaches in systems with poor diatom-TP relationships. Despite poor performance of the RW model, DI phosphorus data for riverine wetlands, derived from the overall model, wer

The Great Lakes Hydrography Dataset: Consistent, Binational Watersheds for the Laurentian Great Lakes Basin

Ecosystem‐based management of the Laurentian Great Lakes, which spans both the United States and Canada, is hampered by the lack of consistent binational watersheds for the entire Basin. Using comparable data sources and consistent methods, we developed spatially equivalent watershed boundaries for the binational extent of the Basin to create the Great Lakes Hydrography Dataset (GLHD). The GLHD consists of 5,589 watersheds for the entire Basin, covering a total area of approximately 547,967 km2, or about twice the 247,003 km2 surface water area of the Great Lakes. The GLHD improves upon existing watershed efforts by delineating watersheds for the entire Basin using consistent methods; enhancing the precision of watershed delineation using recently developed flow direction grids that have been hydrologically enforced and vetted by provincial and federal water resource agencies; and increasing the accuracy of watershed boundaries by enforcing embayments, delineating watersheds on islands, and delineating watersheds for all tributaries draining to connecting channels. In addition, the GLHD is packaged in a publically available geodatabase that includes synthetic stream networks, reach catchments, watershed boundaries, a broad set of attribute data for each tributary, and metadata documenting methodology. The GLHD provides a common set of watersheds and associated hydrography data for the Basin that will enhance binational efforts to protect and restore the Great Lakes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134077/1/jawr12435_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134077/2/jawr12435.pd