Hiking Tumalo Creek in Bend, OR- wait, what’s that pipeline?

I could try to be coy and let you think that this snowy post happened, say, last weekend and I’m being a timely blogger who never has a backlog, but I’ll be honest. This has been kicking around since my housemate and I went adventuring over Thanksgiving break. Better late than never!

If the campground host tells you that the Tumalo Creek Campground near Bend is only going to get down to a low of 40 degrees in late November, be smarter than me and don’t believe them. On the plus-side, my friend Liz and I were so cold that we packed up camp at 7AM and were the first ones on the trail in a winter wonderland. We had the North Fork trail along Tumalo Creek all to ourselves!

trail map and bend city watershed

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As we hiked up to above Tumalo Falls I felt the ground crunch satisfyingly under my feet. I looked down, and saw that I was walking on these strange, fragile columns of ice! Each tuft was about 1 to 2 inches tall and supported a very thin layer of soil. I had to file it away in my head as “nature is weird”, but once I got home I found out that it’s called needle ice. This forms when the soil temperature is above freezing but the air’s is below freezing. As capillary action pulls water up through the soil it freezes in long vertical strands.

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Tumalo Falls! But why is it here? The sign in the parking lot has a handy explanation – this sheer cliff was created as the headwall of a glacier during the Ice Age.

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Liz was just a little happy to see the first snow on the trail as we climbed… and it got better!

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The trail didn’t have enough snow for snowshoes, but was precarious going in boots. We were glad for our trekking poles.

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After Tumalo Falls, there are several beautiful smaller waterfalls further up North Fork Trail on Tumalo Creek. This one had a prow of rock jutting out in front of it that made a perfectly scenic picnic spot.

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We found a snowman hiding in a hollow log – a little gift from a hiker the previous day!

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Liz contemplating another waterfall along Tumalo Creek.

That day we did the North Fork Trail as an out-and-back route, which took us from 8:30 AM to 1pm. We had hoped to make a loop with the Swampy Lakes and Bridge Creek trails, but the icy trail made for more difficult going than we had planned, and we decided to bail on the 8 mile loop in favor of a 6-mile hike. Heading back to the trailhead around 11AM we started to pass other hikers and a seemingly endless parade of their adorable dogs.

After our chilly hike, I wanted to drive down to Mt. Bachelor to see what a ski resort looked like in the winter. There might be a theme here  – being from a hometown that’s lucky to get an inch of snow, I’m fascinated by my first glimpses of snow sports! Liz kindly humored me, and we drank our pricey hot cocoa on the patio watching the snowboarders and skiers play in the disappointingly thin layer of powder. Mt. Bachelor is a ridiculously perfect dormant volcanic cone – you’ll definitely be seeing more posts about this area when I have time to read up on volcanology. Again, not a subject we have to think about much in Tennessee.

To end the day, we drove into downtown Bend to window shop in the cute town center and have dinner at Deschutes Brewery. We were just in time to watch the Oregon State University versus University of Oregon ‘Civil War’ game….ouch. The Ducks beat our Beavers 69-10. At least the delicious food and beer cushioned the blows somewhat. (The next day, I passed a church’s sign that said “Don’t worry Beavs, there’s still basketball.” Small comfort.)

I couldn’t help but notice that as we crossed the bridge to the Tumalo Creek Trailhead, a large pipe crossed the stream with us. Once in the parking lot, stern “KEEP OUT” notices shepherded us away from a gate to some new-looking buildings by the stream. To make matters more curious to this hydrologist, the trail map warned

“City of Bend Watershed:

Hiker use only (No Dogs, Stock, or Bicycles)

No Camping, No Fires”.

After some Google sleuthing, it turns out that this mysterious complex is the Heidi Lansdowne Water Intake Facility and that pipe is part of a 10-mile aqueduct that runs under Skyliner Road to the Outback Water Treatment Facility just west of Bend.

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Image showing the original 1926 Bend water systems from a 2014 presentation by Heidi Lansdowne

If we had been able to do our whole loop, we would have been hiking through the water supply area for the City of Bend! The rain that falls in this area flows down to Bridge Creek, where a portion of that water is diverted through the Intake Facility into the pipeline before the stream joins Tumalo Creek. The Heidi Lansdowne Intake Facility was built in 2016 to get the city into compliance with EPA regulations requiring filtration of surface waters.

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Picture of the new intake facility from Bend Water Utility

Bend has been meeting its needs with water from Bridge Creek since 1926 when it signed an agreement with the US Forest Service (USFS) allow Bend to manage the Bridge Creek Watershed. In 1926 Bend built a basic intake and filtration facility connected to a pipeline leading to town, and added an additional parallel pipeline in the 1950s. Until 2016,  Bend still relied on these two aging pipelines. In 2014 the city broke ground on the new intake facility with advanced screening to protect fish and provide a better filter to protect against elevated sediment loads caused by wildfires as well as a more modern pipeline running directly underneath Skyliner Road.

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A photo of the pipeline in progress in 2014, from the same 2014 presentation by Heidi Lansdowne

All this rambling to say that there are good reasons that this watershed is protected against:

  • Dogs – minimizing biological contamination from excrement, such as giardia
  • Stock/Cattle – minimizing fecal contamination as well, also the excess suspended sediment that they kick up in streams as they drink
  • Fires – reducing the risk that campfires will turn into wildfires that choke the streams with ash and then increase the risk of catastrophic flooding that could block the intake filters with sediment
  • Campers – because we leave embarrassing amounts of garbage behind
  • Bicycles – mountain bikes carve deeply into the trails, increasing the amount of sediment that is washed into the stream

Seeing as this is the source for much of what flows out of the taps of almost 80,000 people, it’s understandable that the public utility wants to avoid these risks.

To give you a sense of this system’s scale compared to the town, I created a map using GeoJSON.io and Mapbox.com to show Bend, the municipal watershed, the intake and treatment facilities, and the new aqueduct (the dark blue line between the facilities). GEOG 370: Cartography this term paid off!

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References:

Bend Water Utility – Bend Water Project https://www.bendoregon.gov/government/departments/utilities/stormwater/watershed

Bridge Creek Pipeline Replacement Project | City of Bend. (n.d.). Retrieved March 15, 2018, from https://www.bendoregon.gov/city-projects/city-infrastructure-projects/recently-completed-projects/bridge-creek-pipeline-replacement-project
Hammers, S. (2014, May 29). Work begins on Bend’s water treatment facility. Retrieved March 15, 2018, from http://www.bendbulletin.com/home/2114759-151/work-begins-on-bends-water-treatment-facility
No settlement on Bend water project. (n.d.). Retrieved March 15, 2018, from http://www.deschutesriver.org/media/news/no_settlement_on_bend_water_project
Park – Horse Trails Bicycle Trails.pdf. (n.d.). Retrieved from https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprd3797509.pdf
Park, S. (n.d.). Horse Trails Bicycle Trails, 1.
USFS Special Use Permit for City of Bend, October 1976, showdocument.pdf. (n.d.). Retrieved from https://www.bendoregon.gov/home/showdocument?id=33630

 

Road Trip Part 4: Columbia River Gorge

This is the final installment of my series following my father and my cross-country road trip from Tennessee to Oregon so I could start my master’s program at Oregon State University.

Road Trip Part 1: Why are the high plains so flat?!

Road Trip Part 2: Wyoming’s Great Divide Basin

Road Trip Part 3: The Wasatch Range

Day 6: Salt Lake City, through Idaho, to Pendleton, OR. Sorry Idaho, I’m skipping your geology, maybe another blog post…

Day 7: Pendleton, OR to Corvallis, OR!

The last big geologic conundrum of my trip was the giant layer cake of volcanic deposits that came into view along Highway 84 just past Boardman. The Columbia River sliced through it like a knife, revealing stair-stepping steep cliffs.

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Highway 84 clings to the side of these cliffs for dear life, and every now and then a spur road would snake up the cliff to a town perched high above.

Welcome to the Columbia River Gorge! The river has cut 4,000 feet down into almost  basalt deposits up to 2 miles deep over the past 15 millions years, and the results are amazing.

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Tennessee’s only volcanic rocks are thin ash deposits, so this landscape was utterly foreign. My research on the topic was delayed by the first three blog posts and a 20-page paper on the philosophy of geography, but during the week of final exams I found Central Washington University professor Nick Zenter’s engaging video series on YouTube.  He gives a wonderful introduction to the geologic world of the Pacific Northwest in a format that’s friendly to both non-geologists and geologists whose brains are too fried by studying to read off-topic academic journals. Manatash Mapping out of Ellensburg, WA made some of the best maps I found of the basalt flows to accompany his lectures: the one below shows the total extent of the Columbia River basalts! The Columbia Gorge is not indicated on these maps, but it defines the OR/WA border from just south of Pasco, WA to the Pacific Ocean.

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Brown shading = the sum of the area covered by over 300 basalt flows. 63,320 square miles in all!

This giant pile of 41,985 cubic miles of basalt was belched out by a swarm of “dikes”, or vertical ruptures in the Earth’s crust where lava escaped, between 17 million and 6 millions years ago. 80% of this lava came to the surface between 16.5 and 15.5 million years ago as part of the Grande Ronde Member, which we saw as we drove through the Columbia River Gorge. The Grande Ronde basalts flowed out of the dikes in the area where Washington, Oregon, and Idaho’s borders meet on the map below.

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Orange = area covered by Columbia River Basalt Groups, Black lines = approximate locations of dikes

The next map shows the approximate depths of these lava flows, focusing on the Washington-Oregon border. While depths in the Gorge are between 0.5 and 2 miles, the flows are 3 miles thick in south-central Washington!

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These flows continued east, following the path of the Columbia all the way to the Pacific. However west of the Cascades, as we approached Portland, the wetter climate hides the sheer cliffs with a carpet of trees.

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Looking upriver from an overlook near Hood River, Oregon.

But what caused the Earth’s surface to split open and spew out vast sheets of lava? 16 million years ago in the middle of the Miocene period of geologic time, northern Oregon and southeastern Washington would have looked a lot like the fiery slopes of Mt. Kilauea in Hawaii, or Mt. Bardarbunga in Iceland.

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Pendleton, OR in the Mid-Miocene?

Geologists don’t have a definitive answer yet, although many interacting geologic events have been proposed to have contributed to the eruptions.

  1. The eruptions may be related to the historical path of the Yellowstone Mantle Plume, or “hot spot”. The oldest dikes in southern Oregon opened up just as the Yellowstone hot spot was erupting in what is now northern Nevada, directly south of the dikes.
  2. As the North American plate moved to the southwest over the hot spot towards its current position, cracks in the crust radiated northward, likely along lines of weakness between accreted terranes (bands of islands and sea floor scraped onto the continent by subducting plates) and the core of the continental shield.
  3. As the Farallon oceanic plate collided with and sank beneath the North American plate, crumpling the Coast Ranges and creating the stratovolcanoes of the Cascade range, these stresses could have helped open up these dikes. The majority of the dikes are perpendicular to that west-to-east direction of stress, which would be typical, and the eruptions happened directly after the collision.
  4. It’s possible that after the Farallon Plate slid under North America, parts of it tore open along long north-to-south trending lines. A tear in this subducted plate could allow hot rock to rise up from the upper mantle and punch through weaknesses in the crust.

Luckily for us these dikes have been quiet for the past 6 million years, and don’t show signs of starting back up. Nowadays, only water flows through the Columbia River Gorge. I’m looking forward to going back and exploring the many waterfalls that feed into it this spring as during our road trip in late August 2017 the area was ablaze for a different reason –  forest fires!

References:

Columbia River Flood Basalts | Volcano World | Oregon State University. (n.d.). Retrieved December 7, 2017, from http://volcano.oregonstate.edu/columbia-river-flood-basalts
Liu, L., & Stegman, D. R. (2012). Origin of Columbia River flood basalt controlled by propagating rupture of the Farallon slab. Nature, 482(7385), 386–389. https://doi.org/10.1038/nature10749
Zentner, Nick, Narrator. Flood Basalts of the Pacific Northwest. , Central Washington University, 2017, https://www.youtube.com/watch?v=VQhjkemEyUo&t=2967s. Accessed 15 Jan. 2018.