Glen Canyon’s side canyons spring back to life

A Q&A with an ecologist on how Glen Canyon is returning as Lake Powell recedes.

(Rick Egan | The Salt Lake Tribune) South Fork Canyon, in Glen Canyon Recreation Area, on Tuesday, July 12, 2022.

This article is part of a special project on the future of Lake Powell, looking at the reservoir as overallocation and severe drought dry the Colorado River. See more stories here and order a photo poster from the lake here.

Water levels at Lake Powell are dropping.

And as the water recedes, previously buried landscapes are reemerging.

Seth Arens, an ecologist with Western Water Assessment, a federally funded research arm of the University of Colorado, and consultant for his own company Western Climate Services, has been studying nature’s response on these previously covered landscapes.

So, Seth, how much land are we talking about and what are you seeing?

Well, when Lake Powell was at its lowest level this spring, there was about 100,000 acres of land that was previously inundated by Lake Powell that is now exposed. Over the past three to four years, I’ve been conducting surveys in many tributary canyons to the Colorado River and starting this year in the Lake Powell region. What I’m finding is that especially in canyons where there’s flowing water much of the year, that there are relatively native ecosystems reestablishing very quickly on the order of a couple of years. We’re starting to see willows and native grasses. A few years after that, we’re even seeing species like cottonwoods.

What types of animals are starting to repopulate these areas now?

I’m seeing all the animals you might expect to see. I haven’t seen desert bighorn although I suspect that desert bighorn would frequent some of these areas. Beavers are coming back to some of these tributary canyons as well as deer periodically. Another less common animal species — I saw a Mexican spotted owl, which is a very rare species.

How are these areas different now, post-Glen Canyon Dam?

One of the biggest changes is that there’s a tremendous amount of sediment that flows down the river every year that has dropped out in tributary canyons in the main stem of the Colorado River. So, the landscape has changed. One of the questions: “Is sediment going to erode away or is vegetation going to stabilize these sediments?”

That’s a question I don’t have an answer to yet.

What is available to the public now that might not have been available before?

Someone could see places that have been underwater since the late 1960s. There are arches coming out like Gregory Arch. It was completely buried by Lake Powell and now, you can boat underneath it. You’re also seeing relatively lush desert ecosystems. So, while there is something lost by Lake Powell being lower and boat-based recreation being more difficult, I think that there’s something gained in visiting the landscapes that were once buried by Lake Powell. Some of the places have been out of water for 20 years. If I had not known there was a lake there, it might have been a little tricky to spot that.

Is there anything else that readers should know?

I do want to make the distinction that not all the landscapes that are emerging from under Lake Powell are these lush environments. I’m only seeing this in places where there’s flowing water. There are a lot of dry canyons and large areas like Bullfrog Bay where there’s not the same sort of rapid re-establishment of healthy ecosystems.

I think those areas will take much longer because there’s less water. Of these 100,000 acres of land that’s exposed from Lake Powell, probably the majority of that landscape does fall under the category of drier landscapes.