The sample dataset was divided into a calibration dataset and a validation dataset. The calibration dataset consisted of 23 sites in ecoregion I1 and 67 sites in the eastern plain aquatic ecoregion (75% of the entire dataset). We used 10 reference sites and 13 impaired sites for MMIW development in ecoregion I1, and 12 reference sites and 55 impaired sites were used for MMIE development in ecoregion I2. The remaining seven sites (three reference sites and four impaired sites) in ecoregion I1 and 23 sites (four reference sites and 19 impaired sites) in ecoregion I2 were used for MMI validation (Table 3).