Embedded Files
River: Logan
Reach: From Stokes Nature Center to the Hwy. 89 bridge (~0.25 miles)
Date observed: January 12, 2025
Geomorphic unit notes
Riffles and pools. In the straighter section of this reach there are step pools with elevation changes of ~1-2 ft. Riffles are shallower and longer in the curvy parts of this reach.
It looks like the two inside bends I observed have point bars that got colonized by woody vegetation and are now more like floodplains that are a few feet taller than the channel bottom. However, this whole area is altered by road and trail construction, so maybe excess sediment was put there during road construction.
Reach notes
This reach has two places where the River bends and we see some lateral channel migration (although confined by the trail and road). On the straighter section, there are steeper drops.
This reach has lots of large woody debris.
There are two dams upstream of this reach.
Landscape unit notes
This reach isn't exactly headwaters, although surrounded by steep mountains. Maybe we could call it mid-catchment; it is located just before mountains transition to valley floor. This section of river is influenced by steep, eroding mountains, karst (swiss cheese) geology that could add and remove groundwater, and potential of landslides/avalanches that add sediment and debris to the River.
Overall, in context of the whole River this is probably a section where most sediment is getting eroded away or getting transported downstream. This area is right on a fault zone (although I don't understand what that means for the River).
Catchment notes
The watershed feeding this reach is mostly forest and rangeland of the Bear River mountains.
Main rock types are limestone and dolomite, among others.
Other notes
Beaver chewed trees, not fresh
Clear signs of bank reinforcement on the north bank near the highway
Dormant vegetation: cottonwoods, red osier dogwood, coyote willow, crack willow, elderberry, other woody species
Substrate ranges from sand, to pebbles that are a few cm, to cobble to large >1m2 boulders
Water was just a few feet deep in this stretch
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