The landscape of the western Washington low lands is full of valleys with undersized streams. That is, the existing stream in the valley did not erode the valley. Some past larger water flow carved the valley that is now occupied by a rather smallish stream. Many of these valleys were formed during the late stages of the last glacial period as ice retreated from the western Washington low lands. Large rivers diverted by glacial ice carved deep valleys and then found new routes as the ice retreated and opened up new paths for water flow.
A great example of one of these valleys is just north of Bellingham. It is a rather pretty valley with a mix of mature second growth forest and pastures without too much in the way of rural sprawl so it has maintained its rural character despite its proximity to Bellingham.
View of Squalicum Valley from Van Wyck Road
The above view is actually a section of the valley upstream of Squalicum Creek proper
This valley shows up even on topographic maps as an obvious glacial river channel, but LiDAR imagery makes an even clearer picture.
A river incised down through the landscape when the ice margin was a bit north of Bellingham. Perhaps it was a river of melt water issuing from the margin of the glacier or it may have been a diverted Nooksack River. The Nooksack currently flows from southeast to northwest across the northeast comer of the image. If the river had been present its path would have been blocked by the ice and diverted southward to what is now Bellingham.
Additional channels of similar size can be seen to the north of Squalicum Creek. These too were formed by past larger volumes of water as the glacial margin retreated further to the north. (There has been suggested ideas of readvancing ice as an explanation as well, but that idea has been loosing favor of late).
Just northwest of the name Bellingham on the LiDAR image, the valley fades away and a narrower valley continues to Bellingham Bay (the squarish cut out is an old gravel mine). This area was formerly a delta area and suggests that the large Squalicum Creek valley was formed when local sea level was substantially higher than present as the area had yet to rebound from the mass of glacial ice. I came across some marine fossils very near Squalicum Creek in Bellingham (tube-worms-in-bellingham-drift). As rebound took place Squalicum Creek down cut through the rising terrain.
The comparison of the upper broad deep valley with the lower narrow valley is informative. The existing lower valley carved by Squalicum Creek is dwarfed by the much larger valley it occupies upstream. Squalicum Creek has occupied the lower valley for something on the order of 12,000 years. The upper valley was likely carved over a period of less than 1,000 years and perhaps even less than 100 years.
8 comments:
Two notable things for me about the Squalicum Creek valley:
1. I have commuted through this valley on Noon Road for years. Except during summer heat periods, the valley is always colder than the plateaus around it. I have seen as much as 8 degrees temperature difference between Mt Baker Highway and Kelly Road. Usually it's about 4 degrees difference, particularly in the morning.
2. An abandoned railroad line - long since dissected and sold to adjoining property owners -follows Squalicum Valley. The former rail line is proposed by parks advocates to become part of the envisioned "Nooksack Loop Trail". I have skepticism about this portion because the old rail right-of-way is now integrated into private ownership with dozens of parcels between Bellingham and Everson, and many property-owners are adverse to the idea of a trail transecting their rural privacy. In that regard, I will never support a "push" for eminent domain on these property owners, as I doubt every one of them will agree to trail development, even with offers of compensation.
Looks like the SCOTUS settled rails to trails today (3/10/2014). See: http://www.scotusblog.com/2014/03/opinion-analysis-victory-and-money-for-landowners/
8-1. Rails to Trails was once a good idea.
Funny thing about these two comments on rail to trails - I just got back from assessing an old rail grade for a rail to trail project. The rail grade is owned out right by the property owner so SCOTUS is not a specific factor but perhaps it is elsewhere on this project.
I don't think yesterday's SCOTUS decision would have anything to do with this trail if it where proposed for a RTT. Is there any proposal out there for this one, because I haven't heard of any It's actually a very narrow decision, only involving the 1875 ROWs. Yesterday's decision has hit the blogs as a victory for property rights, which gives RTTs a rhetorical punch. I think this ROW would be later, but don't know. Most Whatcom RRs were private logging routes, without a land grant provision. If the law's on your side, argue the law. If the facts are on your side, argue the facts. If neither apply, pound the table.
I attended a presentation on LIDAR given a few years ago at WWU and evidence was presented that not only the Nooksack, but perhaps even the might Fraser River may have prehistorically flowed in Squalicum valley . A lingering lobe of continental ice in the area of what is now Langley, Delta, and Richmond, BC blocked the Fraser from flowing into the Georgia Strait and diverted the river south across part of western Whatcom County.
Interesting!
I am in a group of WWU geology students recently conducted a analysis of the delta sediments left near Squalicum and Baker Creek confluence for our Geomorphology class. The poorly graded sediments and the orientation of the SW dipping beds both confirm the existance of the delta formation, but we were not sure whether it was an outwash delta from the glacial activity or a diverted stream channel. We approximated the discharge and velocity of the channel and found the size of Squalicum Valley would have produced a stream on the order of the magnitude of the Columbia River at the International Border Crossing (160,000 cfs). The purposed delta has a larger sediment size compared to the lower meandering channels of the Fraser and Nooksack rivers, so with the assortment of boulders and cobbles found (Chuckanut sandstone, quartzite, and granite) we hypothesized that Squalicum Creek Valley might have been an outwash channel derived from the glacier itself, but it does make sense that if it was the Fraser that was diverted, then all those sediment types could have been transported to this area from interior BC.
Thanks Matt for that bit of perspective. That is a lot of flow down this valley!
Just saw this post as well, Dan...nice summary (and glad to see Matt, one of my geomorph students last quarter, post his findings here). To follow on Doug M.'s comment, it's fairly clear from the scale of the meander wavelength that the river that formed the main Squalicum channel was closer to the scale of the Fraser River than the Nooksack. The Lidar also shows that the river emanated from the terminus of the glacier near Everson-Goshen Rd; there is a terminal moraine there that the channels grade to, so it wasn't simply a diversion of the Nooksack.
A final interesting point is that I recently got new 14C ages back from a sediment core of Squalicum Lake that show the channel likely formed slightly before 13,000 years ago (calibrated). That puts it somewhat older than previously though. I also concur with your thinking that the channel (and the delta Matt studied) likely formed in only a matter of a few tens to hundreds of years, based on the restricted size of the delta and the fact that relative sea-level did not lower much while it was forming. The rebound appears to have been remarkably rapid, so this channel had to be short lived.
Great stuff!
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