Last week I (Kathy) met with Kieran, of Watershed Management Group, at a plot of land owned by Pima County in southeast Tucson along the Santa Cruz River. Watershed Management Group works with the county on watershed restoration projects, and this 40-acre open space is just one example. Here’s what it looks like now, in the second year of the effort:
Like many areas intended for development, the desert was “scraped,” leaving nothing but bare soil. With nothing to hold it in place, blowing dust becomes a problem. And it can take 20 years or more for anything to grow back because we only get 12 inches of rain a year.
Kieran’s three goals for this property are to stop wind erosion, cover the soil, and improve water infiltration. If you look carefully at the picture above, you’ll see a small green strip. That’s last year’s first step in this restoration project – they created several water harvesting areas to collect summer monsoon rains flowing down the nearby neighborhood streets. They planted bushes and trees, supplemented with “Dry H2O” to get them started, and they also seeded with a native revegetation mix. This is how it looks now, which may not seem like success to many of you, but that almost all the trees and bushes survived without any supplemental watering and there’s some grass and forbs is a miracle in this area.
So what comes next? Kieran asked me and a local shepherd, Beryl Baker, to talk about how animal impact might help in the process. We talked about how hoof impact might both prevent and increase soil erosion, the benefits of laying down animal manure, and then the potential problem of too much fertility being added to the soil. It turns out that native plants here are adapted to low fertility soils and when we add things like compost and manure, we can prevent them from growing. We talked about using cows, goats, sheep and even chickens. I’ve been dreaming of starting an urban chicken egg and meat project for a long time, and am excited that this might finally be the time and place!
One of the areas we took a closer look at was this growing rill erosion where water is running off the armored area where “The Loop Trail” runs alongside the Santa Cruz river. These rills are a common problem in general with some areas having rills that are six feet deep and more.
One of the ways a local copper mine dealt with this issue was unrolling hay and letting cattle graze on it to stomp it down and prevent further erosion. They apparently gave that up for a different solution, so we’re going to get in touch with them to find out more about how that worked for them. We’re also going to get in touch with the Santa Rita Experiment Station, some folks at the University of Arizona, and some others who have been involved in somewhat similar restorations along the river to see what kinds of science, lessons learned, and suggestions they might have for us.
I’ll share more as we go along. Meanwhile, if you have ideas and experience with this kind of environment, do share!
Thanks for reading!
Kathy and Rachel
P.S. And here’s what the Santa Cruz River looks like – not a river at all until the monsoons come. Then it runs fast and deep carrying water out of the valley and on to the ocean.