About

About this dashboard

Flooded acreage at Blackrock Waterfowl Management Area (BWMA) supports seasonal water and wildlife management. This site publishes monthly estimates derived from satellite imagery, replacing multi-day field GPS walks for routine monitoring.

Data source

Sentinel-2 Surface Reflectance (harmonized collection) via the Google Earth Engine Python API. S2 revisits every ~5 days with 10 m visible/NIR bands used for water detection.

Method

The Near Infrared (NIR) band is thresholded to separate open water from vegetation. Each monthly run uses a 15-day window starting on the 1st of the month, building a cloud-masked median composite across all qualifying scenes—not a single acquisition.

Since April 2026, that composite workflow is the official monthly procedure (mid-month run, start date YYYY-MM-01, threshold 0.14). Earlier archived reports used the same median code but were often generated on ad-hoc dates; their file names and legacy pages may show a label date that is not a single scene.

Field crews validate predictions during avian surveys across the flooding cycle (typically September through April).

Management target

Operational planning references roughly 500 acres flooded between November 1 and March 1. The dashboard chart shows that target as a dashed reference line.

Monthly reports include per-unit acreage for Thibaut, Drew, Waggoner, Winterton sub-units, and Thibaut Ponds.

What’s next

Sentinel-1 SAR and optical–SAR fusion scripts exist in the repository for emergent-vegetation masking but are not part of the published monthly workflow yet.