Michigan Dept. of Environment, Great Lakes, and EnergyRapid, qualitative biological and habitat surveys for wadeable streams and rivers are conducted using the Great Lakes Watersheds Assessment, Restoration, and Management (GLWARM) section Procedure 51 . Procedure 51 consists of separate qualitative evaluations of the macroinvertebrate community, fish community, and habitat quality. These protocols can be used to assess the existing condition of Michigan's wadeable streams and rivers as well as detect spatial and temporal trends. This layer was developed to classify sites for the Water Resources Division Procedure 51 scoring process. The classifications were partly derived from EPA's StreamCat Dataset catchments and Level 3 Ecoregions , where ecoregion, catchment slope, and wetland composition, are components of the site class determination. The north region is comprised of catchments within level 3 Ecoregion 50: Northern Lakes and Forests and Ecoregion 51: North Central Hardwood Forests. Monitoring sites within the north region are classified according to stream width and percent coverage of wetland and open water land cover types according to the table below. North- Wetland > 40%: Stream Class Stream Width (ft.) Very Narrow < 13 Narrow 13 - 21.27 Wide OR Mid-Size Wet 21.27 - 68.367 Wide OR Mid-Size Wet > 68.367 North- Wetland < 40% Stream Class Stream Width (ft) Very Narrow < 13 Narrow 13 - 21.27 Mid-Size Dry 21.27 - 68.367 Wide OR Mid-Size Wet > 68.367 The south region is comprised of catchments with level 3 Ecoregion 55: Eastern Corn Belt Plains, Ecoregion 56: Southern Michigan/Northern Indiana Drift Plains and Ecoregion 57: Huron/Erie Lake Plains. Longitude -83.72 is used to divide the East classification from both WestFlat and WestSteep classifications. Please note that catchments whose boundaries intersected the north/south ecoregion boundary and the -83.72 longitude were split accordingly. These fragmented catchments retained their original % Wetland and % slope values from the StreamCat dataset for classification purposes . These values are not representative of the actual composition within those areas, they correspond to the original catchment boundaries. Learn more about EGLE Biological Assessments Questions about the data and P51 site classifications: Sarah Holden at HoldenS1@Michigan.gov Map feedback: VandenbergC@Michigan.govArcGIS FeatureLayerhttps://hub.arcgis.com/datasets/766162c7f70948a096f2cec7b8bd1fc9_0engState of Michigan Open Data PortalPublicProcedure 51 Site Classifications [Michigan]Web servicesMichiganLast Modified: 2025-09-17