Wetland inventory ArcGIS layers for the Beaver Island archipelago

Summary

The project now has a reproducible ArcGIS-backed wetland data stack rather than one undifferentiated “wetlands” map. The federal source is the official U.S. Fish and Wildlife Service National Wetlands Inventory (NWI) MapServer. The Michigan EGLE Wetlands Map Viewer supplies a hydric-soils screening layer, a state-hosted 2005 NWI layer, and a potential-restoration layer. The sibling ../geodata package contains the reusable ArcGIS client and source registry for these services.

The held files are archipelago-region snapshots. They are useful for joining wetland classifications to named places, soils, circa-1800 land cover, forest types, and wildlife records, but they are not legal delineations, field surveys, or proof that an individual parcel is wetland or non-wetland.

What is held

The federal NWI snapshot contains 496 polygons. Its class field includes forested, emergent, scrub-shrub, unconsolidated-bottom, aquatic-bed, and unconsolidated-shore classes. Because the query frame includes surrounding Lake Michigan and inland waters, those counts must not be read as an island acreage table. The source’s ACRES field also includes a very large open-water feature in the frame, so the archive does not report its raw sum as wetland acreage.

The EGLE snapshots contain 257 hydric-soils features, 496 NWI-2005 features, and 297 potential-restoration features for the same broad frame. The data were collected with the ArcGIS REST service and direct OID-paginated queries. The EGLE service’s tiled query path did not return features consistently for these layers, while direct bbox-plus-OID pagination did; that processing distinction is preserved in the provenance sidecars.

The sibling registry also identifies the Esri Living Atlas NWI mirror and EGLE layers for draft NWI 2015 and NWI Plus. The tested archipelago query returned no features from those two EGLE layers. That could reflect coverage, service filtering, or layer semantics; it is not evidence that the islands lack the mapped conditions.

Historical and ecological connections

The 2017 Master Plan describes coastal wetlands as hydrologically connected to Lake Michigan and identifies inland lakes, fens, bogs, and streams as a linked habitat and recreation network. The NWI and EGLE layers give that planning language a machine-readable spatial counterpart. The 2023 plan’s account of Miller’s Marsh, the 2024 MNFI landowner guide, and the named records for Lake Geneserath and Gull Harbor provide place-specific interpretive anchors.

The state’s circa-1800 land-cover reconstruction is a different evidence class: it models historical vegetation from GLO survey notes, while NWI describes modern mapped wetland/deepwater classes. Comparing them can identify candidate areas of continuity, drainage, filling, shoreline change, or classification change, but a polygon overlap is not by itself proof of ecological continuity.

Added 2 August 2026. Recent changes