Bighorn Sheep and Channel Fill

Bighorn Sheep and a “channel fill” are seen in this arresting photo by Britt Runyon (below), taken in the Taos Box portion of the Rio Grande Gorge. “What’s a channel fill?”, you say?

OK, I’ll explain. But first, I need to discuss the geologic history of the Rio Grande Gorge. In this part of gorge, the Rio Grande is incised into a succession of lava flows, one sitting atop the other, like a layer cake – and I’ve counted as many as 7 different layers in that cake. Before these lava flows began, let’s suppose that the Rio Grande was running through a valley, as rivers do. The first lava flow into that valley dammed up the river, causing a lake to form behind the dam. When the lake rose to the height of the lava dam, its waters began to spill out and meander over the surface of the lava flow. Depending on the amount of time that elapsed between the over-topping of the lava dam and the arrival of the second flow, the Rio Grande would (with less time) have  cut a channel into the flow, and (with more time) cut a gorge. This same process would have repeated with the arrival of each new lava flow. The Rio finally had the opportunity to cut down more fully through that stack of layers once the lava flows stopped coming.

So, what about that channel fill? In the upper part of the photo, four Bighorn sheep are seen standing on a tan layer of rock, that looks nothing like the basalt rocks seen above and to the side (when hardened, this kind of lava is called basalt). That tan rock is, in fact, hardly rock at all. It’s dirt! And how did it get there? It’s sediment that collected in a stream channel that ran across the surface of a lava flow. The part of the channel seen in the photo narrows to the right side, being a partial cross-section of the entire channel. And then what happened? Down came another lava flow, which capped that channel fill, preserving it for all time. Additionally, the molten lava that covered over the channel fill baked that material, giving it a reddish cast.

Channel fills like the one seen here are seen elsewhere, and at different levels, in the walls of the gorge, being situated upon the top of one flow or another. They really stick out, and once you know what you’re looking for, you begin to recognize them.

Bighorn sheep and channel fill

Channel fill at the base of a basalt cliff

Channel fill at top of cliff (“X”), staining the rocks below

Channel fill (“X”)

See Bighorn Sheep in the Taos Box

See Bighorn Sheep in the Taos Box. Many bighorn sheep, with newborn lambs, were seen on our Taos Box raft trip of 5-20-17. The sheep come to river-side at this time of the year to graze on the new grass and other vegetation just now showing up. There may be no better way to come into such close contact with these magnificent wild critters, which may be a better reason for running the Box than the whitewater itself!

Baby Bighorn sheep of the Rio Grande.

Lamb, Taos Box run, Rio Grande del Norte National Monument, New Mexico. Photo by Britt Runyon, 5-20-17

Bighorn sheep of the Taos Box.

For these wild creatures, there’s safety in numbers. Photo by Britt Runyon.

But, while speaking of the whitewater – it’s not too shabby right now! We are having, at the moment, very exciting rafting on the Rio Grande, and we anticipate yet more exciting rafting as, in the next month, the river rises to levels that exceed what we’ve seen so far this season. It’s been chilly this spring, leaving plenty of snow still in the mountains … and that snow will start melting in earnest when hot weather finally arrives (temps in the 80s). The first week in June is when the big melt usually hits, and that is just around the corner.

We’re expecting the Rio to exceed 4000 cfs, and perhaps much more than that, at the peak of run-off. Levels at or beyond 4000 cfs make the Taos Box a white knuckles non-stop roller-coaster ride, and bring the Racecourse up to Class IV difficulty. You will not forget your run through Souse Hole (on the Racecourse) at that level! And you will be insisting that your friends look at the photos of you in either Taos Junction Rapid (the Taos Box) or Souse Hole, on the Racecourse.

Call us now, and mention this blog post to receive a 10% discount on any trip. Adventure awaits!

Photos and video by Britt Runyon, NWRCo guide and photographer extraordinaire!

Wild Roses Along the Racecourse

Wild Roses Along the Racecourse. It’s that time of year again, when the wild roses bloom along the Racecourse. Their fragrance beats domesticated roses hands down.

Wild roses, at the County Line take-out.

Wild roses, at the County Line take-out.

The apache plume are also blooming, and the canyon grape is leafing out. The flow is 1200 cfs, and will very likely continue to rise. Here’s another photo,  that is a real puzzler.

This is a basalt boulder that is found along Hwy 68. within a quarter-mile of the County Line take-out. See discussion that follows.

This is a basalt boulder that is found along Hwy 68. within a quarter-mile of the County Line take-out. See discussion that follows.

This boulder consists of separate, individual, lava flows. Here, the boulder sits in such a way that the oldest flow layer seen in the boulder faces up (the layer to the left). The individual flows incorporated into the boulder include one whose upper surface is decorated with a swirl pattern, which pattern was created as the lava slowed down and eddied, before hardening. This patterned surface acted as a mold, when it was covered by a subsequent flow. The lowermost surface of that overlying flow is a cast from that mold. The reddish rock surface, in the center, is the cast of the flow pattern found on the surface of the older flow (hidden from view).

Birds of the Box, Rio Grande del Norte National Monument

Birds of the Box, Rio Grande del Norte National Monument.  Birds love rivers! Some birds eat fish, some eat insects that hatch out of the river, some eat subsurface insects, and some eat river-grown vegetation.


You know what the Great Blue Heron eats – everything that moves!


This is an American Dipper, or Water Ouzel. It dives to the bottom, where it probes for invertebrates, like the nymphs that fly fishermen imitate.


This nest has been used by ouzels for decades! As can be seen, it’s located within splashing range of some whitewater. Guess the name of that whitewater! Yep, it’s Ouzel Rapid.


The Black-crowned night heron comes out during the day, as well as at night.


Is this a Canadian goose … or a Canada goose.? He (or she) is the latter. They are also known as “honkers”. They eat grass.


What are these American cliff swallows up to? Well … they build spherical mud houses under overhangs. Here they’ve been disturbed, while gathering mud.


One of the prettiest birds you’ll see along the river – the Western tanager. But you have to be looking for them at the right time of the year. They are springtime migrants, using the Rio as a migration route.

These wonderful photos are by Britt Runyon, Operations Mgr. of NWRCo. He guides the Box all summer, and is never without his Nikon DSLR and 300mm telephoto lens. Nice work, huh?

Cast of Lava Flow Pattern

Cast of Lava Flow Pattern. Appearing in yesterday’s blog was a photo of a basalt boulder, showing a preserved lava flow pattern. Basalt is the name given to the rock that forms from a very common type of lava. Basaltic lava is called “pahoehoe” in Hawaii. It flows with the consistency of pancake batter, and preserves flow patterns when it hardens. The pattern seen in this boulder is in fact a “cast”. It was formed when lava flowed over a hardened prior flow that had a preserved flow pattern on its surface. This pattern constituted the “mold”. Ultimately, the boulder broke in such a way as to reveal the cast.

Cast of lava flow pattern

Cast of lava flow pattern


Solidified flow pattern in what is called “ropy lava”

Crane Fly, a graceful insect

This is a very graceful flying insect commonly encountered along the Rio Grande and other rivers. It spends most of its life on the bottom of the river, in the form of an ugly worm, where it is a favored trout food. Although it looks like a giant mosquito, don’t swat it. It doesn’t bite!

Crane fly

Crane fly

Prickly pear blooms at NWR Headquarters

We’ve seen the claret cup cactus, the green hedgehog and the yucca bloom. Now it’s prickly pear time. Next up is the cholla, so stay tuned. Here’s a photo of the yellow prickly pear blooms outside our home/office, in Embudo, “on the banks of the Rio Grande”.

Embudo, NM

Prickly pear at the NWR headquarters, in Embudo, NM