were certainly moving as bedload in this ephemeral wash below Adobe Mesa during the flash flooding events this summer. Here they now sit, shingled on top of one another, likely stranded for a decade or more until mobilized in the next extreme hydrologic event in this drainage.
As artificial as the sky and cloudscape appears in this image, it was that lovely of a day in Castle Valley.
occurred above the bridge on Castleton Road during this summer’s flooding, clearly evident from examining these images taken three years apart. Compare and contrast.
THEN: Castle Creek on 17 November 2021.
NOW: Castle Creek on 31 October 2024.
throughout Castle Valley is clearly seen in the recently updated satellite imagery available in Google Earth and Google Maps. Light-colored sedimentary deposits paint the areas affected by overland sheet-flooding and where floodwaters escaped ditches and natural channels. Compare and contrast.
Imagery date: 7 August 2024.
Imagery date: 14 October 2022.
Hint: Learn to use the time slider tool in Google Earth to time travel into the past and examine earlier satellite imagery.
of the steep gradient, coarse-grained and ephemeral Placer Creek channel through time, coupled with headcutting by knickpoint migration through the stream crossing, has created a challenge in upper Castle Valley for road maintenance. Compare and contrast the conditions that existed five years ago and today.
Placer Creek crossing on 1 May 2019. Note crushed culvert and concrete on downstream side of roadway. By attempting to maintain this knickpoint in the stream profile for the long term only exacerbated the erosion that eventually occurred here.
Placer Creek crossing on 30 June 2024. Significant scour has deepened the channel once again. The knickpoint has migrated upstream and behind the two large boulders on the left.
The road crossing is now graded to a more stable position in the short term, at the same elevation of the stream channel both upstream and downstream, now that the knickpoint has migrated upstream and no longer occurs right at the crossing as seen in the early image.
View upstream showing the knickpoint in the stream channel that will continually erode upstream with future events.
on display in the canyons, washes and arroyos in mid- to upper-Castle Valley as a result of an intense thunderstorm two days ago. Erosion and sedimentation has occurred across a widespread area - both in and out of channels - but no structural damage was observed anywhere.
occurred late this afternoon in response to an enormous storm cell that passed over the valley dropping about a half-inch of rain in less than an hour on hard-baked soils. Overland flow and sheet-flooding began immediately and ditches ran at full capacity along roadways for more than an hour. The National Weather Service did post both flash flood and severe thunderstorm warnings for the region and the last time an event this intense occurred was around 2010.
Peak runoff down the lane occurs as the storm cell moves eastward, with both roadside ditches running at full capacity. But a rainbow appeared and no personal property was damaged.
The low swale on the east side of my property took some runoff and sediment from small breaches in the berm along the roadside ditch.
UPDATE: The morning after in the mud bowl as the Town’s grader gets to work. There’s a lot of ditch maintenance that needs to happen beyond just clearing debris from the road surfaces.
for this runoff season will certainly occur this week, and here it is running at 20,700 cubic feet per second (cfs) around noon near Moab, Utah. While this sounds impressive, it is less than half the peak discharge of the previous water year. Median peak flow is 20,100 cfs based on 105 years of record at the Cisco gage so this is a normal year.
of Castle Creek where most of the streamflow is routed into a sluice which then enters a 1.8 mile-long (2.9 km) pipe and is ultimately delivered to a farm’s irrigation headworks lower in the valley. The natural river channel is mostly dry for the next two miles until the point where excess water is returned to the creek.
Two observations: 1) It’s not exactly a healthy riparian system, and 2) blue tarps have limitless applications.
View upstream.
View downstream with the natural channel of Castle Creek off to the right.
in the high country with the La Sals completely immersed in a huge snow squall.
One week past the historic median peak, based on more than 40 years of record in the La Sal Mountains, the SNOTEL network reports there is 129% of the median snow water equivalent in the snowpack. Most excellent.
maintain the snowpack in the high country at near normal levels while misting the lower valley with light rains. Springtime approaches in the high desert.
A window to the snowy high country opens behind Round Mountain this afternoon.
Lasal Mountain (572) SNOTEL hydrograph: Black line indicates the current water year snow water content, closely following the median value (green line) based on 41 years of record at this station. Last year’s historic snowpack is represented by the purple line for comparison. (Graph from NCRS SNOTEL network.)
17 March 2024 update: This SNOTEL station now reports 119% of median SWE!
and sitting patiently for millennia, this pair of 1.5+ meter diameter sandstone boulders lie on an old alluvial fan surface below Round Mountain. These enormous clasts were likely entrained in a viscous slurry of water and sediment that moved down the steep topographic gradient, perhaps mobilized by an intense rainfall event, countless centuries ago.
And it was a beautiful - but blustery - day for a ride.
but only several inches of snow has fallen in Castle Valley, though the high country has been elevated to 90% of median snow water content for this time of year. It hasn’t stopped me from patrolling the trails and all the tire tracks be mine.
dresses the high country in the La Sal Mountains in the wake of the first real winter storm of the season, with thee to six inches of accumulation being reported at the SNOTEL sites. It will be interesting to see what this winter brings after last year’s record breaker.
Click on image to enlarginate.
on the first of October and nature delivers the first seasonal snow to the high La Sal Mountains just a day later. Winter is coming, but let’s enjoy autumn first.
and very reliable, surging in 15 minute-long cycles of enormous discharge, then completely shutting down for a similarly long recharging period. This unusual and extremely rare hydrologic phenomenon is the outlet of a confined karst aquifer system hosted in the Madison Limestone. The intermittent spring lays in a deeply recessed canyon near Afton, Wyoming and requires a slow drive on a potholed gravel road and a short hike to reach.
Here is a well presented description of the spring, including an explanation of the mechanism at work: Geology of Wyoming - Periodic Spring.
Closer view of the modified spring orifice under flowing conditions. I recorded a time-lapse video of the spring over several cycles with a GoPro, tripod seen at left, and will post it here in a little bit.
UPDATED 19 September 2023: Here’s the time-lapse video of Periodic Spring through several cycles of discharge and recharge, each about 15 minutes long, shot over about 45 minutes. It’s magic!
at the Cisco, Utah gaging station peaked on 19 May 2023 at about 41,000 cfs (cubic feet per second) despite the near record snowpack in the high country of Colorado this water year. It is interesting to note that last year’s peak flow of about 16,000 cfs occurred at about the same time (see hydrograph below) which strongly indicates that upstream diversions are robbing water from the main stem.
at a turbid but moderate pace, with plenty of channel capacity, all the way to its confluence with Castle Creek. Here’s the view upstream from the arroyo at the end of East Pace Lane.
(Click on image to enlarginate.)
this spring in Castle Valley, Utah. Placer Creek is flowing all the way to its confluence with Castle Creek low in the valley, a once-a-decade occurrence, and in doing so is losing a large amount of its flow into the coarse, gravelly ground.
View upstream of Placer Creek and its distant headwaters in the Pinhook Valley, to the right (west) of Round Mountain.
View downstream of Placer Creek at the Buchanan Lane crossing.
is the issue confronting some residents of Castle Valley that live in the so-called Upper 80, where the road crosses Placer Creek. The stream has been running steady for more than a week, eroding the crossing, and the Castle Valley Road Department has used large boulders and concrete in an attempt to limit headward erosion of the nickpoint across the road. This minimal approach is only a band aid solution provided that discharge in the stream does not rapidly increase.
View upstream at road crossing.
View downstream below road crossing.
and the Colorado River has already exceeded last year’s peak discharge of 16,400 cfs at the Cisco gage near Dewey Bridge, Utah that occurred in late May 2022. And snowmelt in the high country hasn’t even begun.
Link: Realtime data for the Colorado River near Cisco, UT - 09180500.