Tucson has changed in the last 70 years. A 1930s photograph of the Santa Cruz River’s West Branch, provided by the Arizona Historical Society, shows a lush, rolling land of green fields, cactus, a flowing river and few signs of civilization in the Kachina Gallery as part of a special exhibit called “”Reviving the West Branch.””

A recent picture of the same landscape, taken by City High School student Erin DenBaars, shows buildings, cars and a barren river. Trees have been replaced by telephone poles.

The coming of civilization brought desolation to the desert.

What happened? That’s what City High School’s sophomores and juniors set out to uncover this semester in their city works class, and the fruit of their learning is on display this month.

Elliott Lax, the city works class teacher, said his students focused on gathering oral histories from people who have lived in the West Branch and documenting the area with photographs. They visited local ranchers and learned about what the future might hold for the animal and plant life in the region.

“”They learned what the Santa Cruz River was like when there was water flowing there, as opposed to now,”” Lax said.

The exhibit juxtaposes a photograph of an overflowing river in the 1940s with a student’s modern-day snapshot of a backyard pool – the only place you can swim near the Santa Cruz River today.

A dog chasing a bike, an abandoned truck sitting in a weed-strewn backyard, a fenced-off pool – these photographs attest to how far the once-flourishing West Branch has changed in less than a century.

Lax said the students took steps toward restoring the local habitat, digging an undeveloped plot of public land near the river to prepare it for planting.

“”This is an attempt to get students to recognize that their voices can be heard, that they can make a contribution to their communities in doing authentic projects,”” he said.

According to Lax, organizations like the Audubon Society, Arizona Open Land Trust and the Southwest Foundation helped the students realize the project.

City High School, which opened in 2004, is a downtown charter school with an enrollment of 116.

“”The school is founded on the principle of civil engagement and community service,”” said Shelbye Reese, graduate assistant for the Union Galleries and art education graduate student.

“”It’s not your typical high school class where you have an instructor telling you what to do,”” Lax said. “”The kids take ownership of the project as much as the community partners do.””

“”Reviving the West Branch”” is on display at the Kachina Gallery on the third floor of the Student Union Memorial Center through June 30. The gallery’s summer hours are 10 a.m. to 4 p.m.