While the preserve has been a spot for 'birding' even before the 104-acre-region flooded during monsoon rains in 2014, recent upgrades like the observation deck, a new parking lot and a crosswalk have made El Rio much more accessible.
"Because of where it sits between the Tortolitas and the Santa Catalinas, the popularity just soared once the water came," said Marana Parks and Recreation Director Jim Conroy.
The observation deck, which opened to the public last December, cost approximately $350,000 and was funded by general funds from the town. With the new improvements, as well as over 240 species of birds to view, Conroy said people are definitely coming to check the preserve out.
Janine Spencer, board member for Friends of the El Rio Preserve and former environmental project manager for the Town of Marana, called the space "an amazing place that you have to see to believe."
"The Tucson Mountains come almost all the way down to the water and we get all kinds of raptors here," Spencer said. "One year, there was a whole group of sandhill cranes that came through and stayed overnight. It was pretty fabulous."
Spencer, who recently retired from the town, said El Rio is important to "birders," or bird watchers as they are better known, because they're liable to see everything from birds of prey like peregrine falcons to waterfowl like Canadian and white-fronted geese there.
"When I was working for the town, we started seeing license plates from all over the country when word got out about the rarities that were showing up," Spencer said.
Last December, the Town of Marana entered into an intergovernmental agreement with Pima County to upgrade the banks around the Santa Cruz River and build a channel from the Cortaro/Marana Irrigation District to El Rio, preventing the preserve from drying up in the summer months. The ability to keep water in the preserve year-round is very important to the bird watching community, Spencer said.
"Birders care about conservation," Spencer said. "We care that birds have a migratory route and safe stop over points with water. Seeing the rarities that show up because of it is pretty exciting."
In 2018, Marana Parks and Recreation teamed up with the Tucson Audubon Society to upgrade the area's flora with pollinator gardens and other plants to increase its bird and pollinating insect populations.
Conroy said Jonathan Horst, Tucson Audubon Society Director of Conservation and Research, has been instrumental in selecting the right varieties, and adding around 200 more plants to the already lush environment.
Horst said the focus of the pollinator gardens is to attract hummingbirds and help increase pollinating insect populations like the monarch butterfly, which has been in decline for the past 20 years according to the U.S. Fish and Wildlife Service.
To Horst, what makes El Rio different than other birding sites is the accessibility to the whole area, with the observation deck, new parking lot and how its located on the Loop bike path.
"There are two great sites in Tucson that are really, really prime birding areas; the Sweetwater Preserve and the El Rio Preserve" Horst said. "Sweetwater only has one space that's easily accessible. At El Rio, you can get to a broader variety of habitat quickly in an accessible fashion."