Pacific Northwest Rivers

Flow Accumulation · 30 m DEM

What you're looking at

The Columbia River system — the only Strahler-9 mainstem in our regional set — drains an area larger than France through the Pacific Northwest. The Cascade rain shadow creates dramatic east-vs-west drainage density: dense networks west of the crest, sparse sage-and-pine drainage east.

Watershed Stats

SourceUSGS 3DEP 30 m

Stream segments166,411 (vector)

Max Strahler order9 (Columbia at mouth)

Notable4th-largest US river by discharge

AlgorithmD8 + Strahler

ToolWhitebox Tools

Major Rivers

Columbia at the PacificS9
Willamette (Portland)S7
Snake / Hells CanyonS8
Cowlitz (Castle Rock)S6
KlickitatS5

How it works

Olympic Peninsula rivers are short and steep, fed by the wettest spot in the contiguous US (Mt. Olympus, ~3,800 mm/yr). The Snake cuts the deepest river canyon in North America at Hells Canyon, where it joins the Columbia. Willamette Valley is the agricultural heart of Oregon — visible as the dense interior drainage west of the Cascades.

Same engine, any scale: this is the same pipeline that renders a 160-acre RTK survey at sub-meter resolution. Only the bounding box changes.

Sources & tools listed at /data