HOMESTAKE WHOLE-COMPLEX WETLAND CONNECTION ASSESSMENT
Prepared 2026-10-06 UTC
Claim HWF:CONNECTED-WETLANDS-C001

The assessment follows complete source wetland and pond boundaries, the named Homestake mainstem and documented valley-floor terrain connections.

36 linked whole complexes contain 362.0581 mapped wetland/potential-fen acres. One complete Whitney complex crosses the upstream start and accounts for 49.2262 acres; the other 35 complexes contain 312.8319 acres. These numbers describe mapped habitat with documented river/floodplain linkage, not a uniform amount of drying or habitat loss. Connection-unresolved valley-margin features remain visible and separately accounted. The complete source geometry of each selected feature is preserved.

Longitudinal extent: earliest existing modeled dam-axis crossing (B) on the named Homestake mainstem to its verified Eagle River confluence, 13,147.1711 m. Source polygons crossing the start are mapped whole and separately identified; a reservoir boundary is used only for scenario accounting. No lateral distance threshold is used.

The wetland/potential-fen union outside each existing modeled footprint is A 296.1216, B 324.6676, C 316.0085, D 287.3113 acres. These outside-footprint areas include portions of the complex crossing the upstream assessment endpoint. The separately reported remainder excluding that complex describes wholly downstream complexes. Each scenario is a separate alternative.

Between Blodgett Campground and the Eagle River confluence, river-linked mapped wetland area is 137.0329 acres. The calculation uses northing gates through the two endpoints and complete wetland complexes across the valley floor.

Wetland/fen and pond classes overlap in the inventory. Wetland/fen area includes the geometric union of those source classes; pond source records are omitted from that input union. The explicit overlap and combined geometry union in connected-wetland-methods.json prevent addition of overlapping habitat categories. Legacy potential fens retain their source classification.

REPRODUCE
After extracting the download, run these commands from the extracted top-level directory in a Python environment with the dependencies below:
  python assessment/reproduce_connectivity.py source reproduced
  python assessment/verify_export.py reproduced
The supplied source/ directory contains the frozen offline inputs in site-checkout layout. The script reads those inputs and writes results to reproduced/. Inputs and SHA256 hashes are recorded in assessment/input-sha256.json. Manual terrain/geometry decisions are frozen in assessment/review-decisions.json and included in source-specific evidence fields.

When working from the full site checkout instead, keep reproduce_connectivity.py, review-decisions.json and verify_export.py together and run:
  python reproduce_connectivity.py /absolute/path/to/save-homestake /absolute/output/directory
  python verify_export.py /absolute/output/directory
The script reads the specified checkout without changing its inputs.

Dependencies verified: Python 3.12; numpy 2.5.3; shapely 2.1.2; pyproj 3.8.0; matplotlib 3.10.8; Pillow. No live service request is required.

FROZEN INPUT LOCATIONS WITHIN source/ OR THE SITE CHECKOUT
  archive/bioblitz-access-map-2026-09-18/whole-valley-sources/
  content/county-1041/research/downstream/lower-creek-2026-10-05/raw/
  content/county-1041/research/downstream/lower-creek-2026-10-05/methods.json
  content/county-1041/research/downstream/lower-creek-2026-10-05/mainstem-and-landmarks.geojson
  content/county-1041/research/downstream/downstream-wetlands.geojson
  archive/valley-explorer/upper-valley/grid-valley-10m.json
  archive/valley-explorer/upper-valley/terrain-valley-10m.f32
  dist/assets/valley/illustrative-scenarios.json

The modeled reservoir axes and footprints define the scenario comparisons. Modeled reservoir inundation covers 85.4–134.8 acres of wetland and potential-fen habitat.

OUTPUTS
connected-wetland-complexes.png/.svg: two-panel Whitney-to-Eagle map, 3220×2185 PNG.
connected-wetland-complexes.geojson: full features, source attributes, linkage class, mainstem, landmarks and modeled reservoir extents. Visible map counts retain all 197 wetland, 310 mapped-water and 26 potential-fen source records; exports preserve additional whole-complex context beyond the map panels.
connected-wetland-methods.json: accounting, linkage method, source ages/coverage and checks.
complex-evidence-ledger.csv: one row per complex with exact source IDs, linkage explanation and per-alternative reconciliation.
review-decisions.json: explicit terrain-review overrides at existing source boundaries.
input-sha256.json: input JSON, DEM and hillshade hashes.
verification.json: separate area/geometry recomputation from the delivered GeoJSON.

SOURCE COVERAGE
CNHP exports match the complete identifier sets for their archived query envelopes. Full source polygons are retained. The inventory omits unmapped features and preserves differing imagery dates (lower-reach wetlands use 1983 imagery). The frozen 10 m DEM ends at northing 4371500; the farther lower reach uses archived hillshade for context. Quantitative lower-reach terrain is not silently assumed. Historical beaver modifiers are preserved as source habitat attribution, not current dam counts.
