Watershed & Hydrological Analysis

Data Source & Methodology

Analysis performed on a drone-derived Digital Terrain Model (DTM) from photogrammetric processing of 8,054 aerial images captured with a DJI Matrice 4TD. The DTM was downsampled from 5cm/px to 1m/px for hydrological processing.

• Depression filling — hydrological preprocessing to remove sinks
• D8 flow direction — 8-direction pour point model for surface drainage
• Flow accumulation — upslope contributing area per cell
• Strahler stream ordering — 1=headwater, 6=main trunk
• Topographic Wetness Index — TWI = ln(α / tan(β)) — saturation potential
• Hillslope delineation — individual slopes draining to each stream link

Tools: WhiteboxTools (open-source), rasterio, matplotlib — all free, no license required.