Few desert dwellers take water for granted. While a rainy day makes visitors sad, Tubac area residents greet each other by saying, “Isn’t it a beautiful day!”

Flowing north through and past Tubac, the Santa Cruz River is a sparkling jewel of the environment. The river supports four native fish species, one of which is nationally endangered.

The river has been here since pre-historic times but when agricultural interests began drawing deeply from wells starting in the 1930s, and when the population began its steady growth in the 1970s, people began to be very concerned.

Even so, the river is healthy and many people are dedicated to taking care of it, while protecting it from overpumping. Alejandro Barcenas is director of the Nogales office of the Arizona Department of Water Resources and much of his work entails studying and protecting the river "to prevent long-term declines in the water table," he said.

Visitors come from around the world to see migrating birds along the Santa Cruz River. Developers tout its lush appearance in advertising. Hikers trek the Juan Bautista de Anza National Historic Trail that parallels the river.

But confusion exists about the quality and availability of the river's water.

Barcenas said a misconception about the river is that it’s contaminated. “The river is pretty clean,” he said. It’s not suitable for swimming or playing in, but that’s because it’s used by wildlife along with cattle and horses from bordering ranches.

About 14 million gallons a day of water in the form of treated effluent enters the Santa Cruz River in Rio Rico from the Nogales International Wastewater Treatment Plant where Environmental Protection Agency standards must be adhered to.

Sherry Sass pointed out that the river isn't comprised solely of treated effluent but it also consists of groundwater that rises to the surface when it's shallow enough. Sass is president of the non-profit Friends of the Santa Cruz River. She's also an appointed member and chairwoman of the Groundwater Users Advisory Council for the Santa Cruz Active Management Area of the Arizona Department of Water Resources.

In terms of bacteria, the treatment plant puts out a clean level of water, Sass said. But it's high in nutrients, on which trees and plants thrive. Barcenas noted, “From the effluent that’s discharged, the only thing we’ve seen that shouldn’t be there is nitrate." Nitrate comes from natural decomposition of organic materials and it’s used in commercial fertilizers, he said.

Sass observed that the river and its surrounding riparian area "is a very dynamic environment. People see the huge cottonwood trees and think they've been there forever. Not true. The conditions for plants change very quickly so these trees are adapted to that," she said.

Other riverside trees include mesquites, Goodding willow, Mexican elder, Arizona walnut and netleaf hackberry.

The people of Arizona own the water in the river, Barcenas said. However, two sets of state laws, one governing surface water and one governing groundwater, can cause some confusion.

For surface water, the oldest or earliest rights are the strongest, he said. "You can stop the rest of the people (from withdrawing water) until you satisfy your needs." For groundwater, everyone is equal. A user must apply for permits, or water rights, which are issued by the state, he said.

Sass sees it slightly differently: "Groundwater and surface water are intimately linked. The shallow aquifer that is mostly sand and gravel overlies a deeper regional aquifer. So if you pump out of a deeper layer, you are going to affect the shallow layer associated with the river," she said.

"Even though there are legal distinctions, they're increasingly difficult to tease apart, because the hydrology is clearer and clearer that these two are really one system," Sass said.

Another misconception, Barcenas said, is that some individuals insist the region has plenty of water because the river is flowing. “I think that’s a misunderstanding of how the system works,” he said. Rather, he said, "There's plenty of water if we don't grow the way we see we're growing."

Meanwhile, "An argument that gets used a lot, especially by developers, is that the trees along the river use a lot of water. It's a fact. They use more water than any other sector. But that provides a value, a quality of life for people."

The river sustains life for plants and animals, but it also makes it possible for thousands of people to live here. “The main source of drinking water for almost everyone in Santa Cruz County is the Santa Cruz River,” Barcenas said. Utility company and private wells draw from the river's aquifers.

In turn, the question that no one seems to be able to answer definitively is how much water is available to sustain the people who live here and the people who would like to move here.

Barcenas said there's no current crisis in water availability. "Right now, we believe we're in balance, but the more time that passes, the more pressure will continue. More developers are coming in, but the water stays the same. We've been in a drought for the last 10 years."

Sass concurs, saying if water now being used for agriculture is shifted to residential use, the balance should remain. "As long as the total demand doesn't exceed what it is now, and we have the effluent, the river has a good future, I think."

Barcenas doesn't oppose construction. "We know growth is needed, economically and socially. A lot of people want to see growth. We don't disagree with that. We just need to be smart. We'll allow the growth to happen in areas where the resources needed are there and in a way that the environmental impact is minimized," he said.

"If we allow the river to be pumped dry, we're going to lose many of the things that people really value here."

Sass has been studying and working for the benefit of the river for 16 years. "The way I look at the river, it needs three things to maintain itself," she said.

"One is water, so the continuation of the river is dependent on the continuation of effluent. With the groundwater pumping (that occurs), probably the river wouldn't exist on the surface, under current conditions if the effluent wasn't there."

The second aspect, she said, is water quality. "High nutrient levels for the plants and trees alongside the river is great. It increases their growth rate and might make them less susceptible to disease. But for the aquatic environment, the effluent has decreased oxygen levels in the water and makes it hard for fish and insects to survive."

A improvement to the Nogales International Wastewater Treatment Plant is anticipated to come on line in about two years. "That will really improve the aquatic environment," Sass said.

Her third concern is land. The river needs a floodplain that has not been significantly modified by developers putting up residential subdivisions. "If it's got that hydrologic dynamic and has shallow groundwater levels, then that riparian environment supported by that can do well, and it does do well. We have some of the premier riparian habitats in southern Arizona.

"But the more you encroach on the floodplain, the more you modify it, the harder it is for the naturally adapted plants and animals to survive. What happens is like the Colorado River delta," where invasive plants restrict the environment, she said. As well, current residential areas might suffer flooding as a result of the modifications.

Finally, both Barcenas and Sass encourage everyone to do all they can to conserve and reduce the water used each day.

A fact-stuffed illustrated paperback book titled “The Life of the Santa Cruz River, A Rambler’s Guide,” is now available for $3 at the Tumacácori National Historic Park. Developed by the Friends of the Santa Cruz River, it lists and describes insects, fish, reptiles, birds, animals, trees, wildflowers and shrubs that thrive along the river.

To join Friends of the Santa Cruz River, visit the web site at www.friendsofsantacruzriver.org or call Sass at 520-398-8269.