Eugene, Oregon – Even a creek with no name deserves some recognition.
This spring, hydrologists with the BLM hiked into the Coast Range foothills outside Eugene to document a stream inception point, where the water first bubbles to the surface.
At 1,200 feet elevation, a barely gurgling stream channel may only be inches wide, just strong enough to move some dirt and pine needles around, said Jonas Parker, a BLM hydrologist based out of Salem.
“You would literally need to get down on your hands and knees to see that scour and channel,” said Parker.
So how does a hydrologist find such a miniscule waterway that is hidden beneath the forest canopy and too small to even make a sound? Old school training, such as being able to identify plants that live near flowing water, is still essential, but the implementation and widespread use of aerial laser imagery helps, too.
Lidar, short for Light Detection and Ranging, is able to see through the vegetation to provide an incredibly detailed scan of the Earth’s surface. BLM field scientists use this imagery in a number of ways. Hydrologists are able to see indentations, natural ridges where water might be likely to pool or flow.
Then the on-the-ground exploration begins, or as Parker said, when the “physical and biological attributes combine.”
Once in the field, hiking through dense Oregon Coast Range forest, spotting plants like ferns, skunk cabbage and devil’s club are sure signs that a riparian area and flowing water are nearby.
BLM hydrology technicians in northwest Oregon have surveyed more than 225 miles of stream so far this year, said Parker. That data can be used in a number of ways, like helping to assess habitat for fish or establishing riparian buffer zones needed for future timber harvests in the area.
Although unnamed, the water flowing out from the inception point discovered in late April can be traced to the nearby Swartz and Lake creeks, and then the Siuslaw River, and finally, the Pacific Ocean.