Integrated freshwater abundance and connectivity clusters at the Hydrologic Unit 8 scale for the Midwest and Northeast U.S.A. – freshwater metric variables and k-means cluster assignment

This dataset includes integrated freshwater abundance and connectivity cluster output,
principal component scores, and lake, wetland, and stream abundance and connectivity metrics
measured at the Hydrologic Unit 8 (HU8) scale for 17 U.S. states in the Midwest and
Northeast regions (appr. 1,800,000 km2). The intent of the cluster analysis is to
characterize the macroscale patterns of the integrated freshwater landscape that includes
lakes, wetlands, and streams and their surface connectivity attributes. We define freshwater
connectivity as the permanent surface hydrologic connections that link lakes, wetlands, and
streams and measure connectivity as the landscape position of systems within stream
networks. Geographic data used in the analysis are in LAGOS-NE-GEO database v. 1.03 (Lake
multi-scaled geospatial and temporal database), an integrated, multi-thematic geographic
database (Soranno et al. 2015). The integrated freshwater clusters were created through a
multi-step process as follows: 1) we quantified multiple freshwater connectivity metrics for
lakes, streams, and wetlands separately, 2) we performed principal components analysis (PCA)
on the connectivity metric values for each freshwater type to reduce collinearity, and 3) we
performed k-means cluster analysis to group spatial units with similar freshwater
connectivity characteristics. The resulting freshwater clusters are representations of the
macroscale patterns of freshwater abundance and connectivity in the landscape.