Aquatic Network Connectivity is an indicator of the Midwest Landscape Initiative’s (MLI) 2023 Midwest Conservation Blueprint. The Blueprint is a basemap of priority lands and waters for conservation across the Midwest consisting of over 20 social and environmental values representing diverse interests across society. This indicator was chosen as a targetable, important feature of the MLI goals that will be used to track conditions over time and prioritize areas for conservation. Indicators were defined through elicitation and prioritization exercises with federal and state participants. Criteria for the indicators includes 1) actionable, 2) measurable, 3) relevant to multiple groups across the region, and/or 4) representative of other social and/or environmental values. This indicator identifies the ability of aquatic species to move unimpeded across aquatic networks within the Midwest Landscape. It prioritizes areas based on the length, in km, of hydrologically connected flowlines within the region. This indicator originates from the National Anthropogenic Barrier Dataset (NABD), the National Hydrography Dataset Plus version 2 (NHDPlusv2), and the USFWS National Wetlands Inventory (NWI). To create this layer, MLI partners, members, and staff completed the following mapping steps: projected all input data to NAD83 (2011) UTM Zone 15N, overlaid large dams onto NHD flowlines, subdivided the NHD flowlines at dam locations, gave each hydrologically connected subdivision a unique identifier, calculated the length of connected flowlines within each unique subdivision, spatially joined the results of the previous step with the NWI data layer to represent actual water features on the landscape rather than flowlines, converted the resulting NWI data into a 30m raster using the length of each unique subdivision as the case field, and reclassified the raster into the following five classes: 1 – 0-1,958 km, 2 – 1,959-3,916 km, 3 – 3,917-13,054 km, 4 – 13,055-75,718 km, 5 – 75,719-332,898 km. Finally, we removed highly altered areas from this layer using our Highly Altered Areas mask. For full mapping details, please refer to the Midwest Conservation Blueprint 2023 Development Process document.
