Improvements at Historic Canoa Ranch
A popular County attraction is starting to see a series of restoration improvements. These will restore natural habitat and improve the visitor experience.
Extensive environmental mitigation efforts either underway or in the works at Historic Canoa Ranch located near Green Valley at Interstate 19 and Canoa Ranch Road, are bringing new water features, walking trails, and native vegetation to a 30-acre section of the property.
“Ultimately what we’re doing is taking an area that has a monoculture of low value vegetation and restoring it to an area of higher value diverse native vegetation,” Pima County Regional Flood Control District engineer Deirdre Brosnihan said.
Historic Canoa Ranch lies within the 4,800-acre Raul M. Grijalva Canoa Ranch Conservation Park, which Pima County purchased in 2001 using voter-approved bond funds. The facility preserves a rich record of the prehistoric people. Native Americans, Spaniards, Mexicans, as well as Anglos were also drawn to the area’s natural springs.
The County has completed numerous improvement projects at the ranch since its purchase. This includes restoration of historic adobe buildings, rehabilitating landscapes, reestablishing water features, and creation of pollinator gardens.
The recent planned work at the ranch property includes removing non-native and low value monoculture vegetation. This will take place over a 30-acre section, as well as removing the top eight inches of soil. The soil treatment will additionally eliminate non-native and invasive seed stock and reserved for use at other onsite work.
Conservation and Restoration Projects
Brosnihan said the area planned for clearing has been overrun with amaranth plants, choking out most other plant life and making the section nearly impassable. Replacing these as well as other non-native or invasive species will be native shrubs and trees. This will help begin the restoration of the site.
“There will be more diversity among the plant life, too,” Brosnihan said.
Also planned are additional water features like those installed in and around the pollinator gardens. Two wildlife drinkers are included. These concrete lined watering holes for animals to drink from refill automatically using a float valve.
Subsequently, Brosnihan said the original drinkers installed in the pollinator gardens served as a good test to see if animals would use them. The test proved a success and prompted the District to install more, larger wildlife drinkers in the mitigation parcel.
“For me it was really interesting to see all of the different species that stopped to use the wildlife drinker,” Brosnihan said.
Wildlife cameras installed near the drinkers have captured images of coyotes, javelinas, owls. They have also captured many other native species that frequent the area.
In-Lieu Fee Program
The District’s implementation of an in-lieu fee program made the 30-acre restoration project possible.
The Flood Control District and the U.S. Army Corps of Engineers worked for several years to develop the in-lieu fee program. Federal Clean Water Act allow for the creation of such programs to mitigate for losses of aquatic resources, which occur as result of development within areas recognized in Clean Water Act regulations.
“Through this program we are able to improve and preserve natural spaces along the Santa Cruz River without added costs to taxpayers,” said Pima County Regional Flood Control District Director Suzanne Shields said. “The additional benefit is that the improvements will be done in an area that is accessible and available for to the public to appreciate.”
Additionally, The in-lieu program established a 300-acre conservation easement at Canoa Ranch. It allows private entities to purchase mitigation credits within the ranch area to offset disturbances to federally recognized aquatic resources. The fees apply to acquisition, planning, establishment, and long-term management of mitigation areas.
Work on the 30-acre mitigation parcel will start in May 2021 and will finally wrap up in February 2022.