Building Erosion Control Structures in the Galiuro Mountains

In 2017, Sky Island Alliance built two ponds on a ranch at the southern end of the Galiuro Mountains.

The intention of this project was to provide a mid-elevation water source for bats (which drink from open water), a layover spot for migratory waterfowl and other birds, and habitat for native fish and frogs — and it was a success: bats found the water quickly, new duck species showed up, and frogs moved right in as they dispersed from the nearby Muleshoe Ranch Preserve run by The Nature Conservancy. Since then, through a partnership with the Arizona Game and Fish Department, work has also been underway to stock these new ponds with native fish like the Gila Topminnow and Desert Pupfish.

Caption: The big pond at sunrise.

Unfortunately, this ranch had a history of overgrazing long before the current owners fenced out the cattle. Despite the abundant regrowth of grasses and other plants on the property in recent years, many of the washes have problems with erosion. This includes the main wash that flows past the two ponds we installed. Unless we did something to address the erosion in this channel, we knew we risked the eventual loss of all the work we put into these water sources. 

It’s been a long time coming, but after years of planning and prepping, Sky Island Alliance staff and volunteers were finally able to install loose-rock erosion control structures along the main drainage channel on the property. This project took place over two weekends in November and December 2021, and it was a huge effort on everyone’s part. Our amazing volunteers, who hauled rock uphill on a winding and very narrow trail to build structures in the uppermost reach of the wash, deserve a huge shoutout for their tireless work!

Caption: Volunteer Vicky loads rocks at the bottom of the drainage. 

In just four days, we were able to install over fifty structures including one-rock dams, rock rundowns, and zuni bowls. Some of these structures were quite large and lots of large rocks were needed to ensure they would remain in place during heavy monsoon storms, but folks were certainly up for the challenge. 

Caption: Crews work on one-rock dams. Clockwise from bottom left — Andrew, Alicia, Isis, Rose, Tom, and Leann.

These structures should not only help fight the erosion we’ve seen on this property (thereby protecting our ponds), but also increase infiltration of water in these drainages and encourage new plant growth. We look forward to visiting this site again next monsoon season to see if anything needs to be done to improve this work. We also hope that we can find more funding to continue our work in other drainages on the property since we have plenty of leftover rocks available for new structures! 

Caption: November group from left to right — Bryon, Alicia, Leann, Heather, Lee, Robert, Andrew, Donito, Bets, Sarah, and Mike. Not pictured: Joe.

Caption: Our December 2021 volunteers from left to right — Bryon, Alicia, Rose, Robert, Leann, Andrew (above), Tom (below), Heather, Vicky, Isis, Eamon, Stacy, Joe (below), Neil (above), and Lee.

View 30+ more photos over on facebook!