Magill Weber/The Nature Conservancy

Dodging quicksand and rattlesnakes, Ted Mouras will spend Saturday morning walking along a five-mile stretch of a remote section of southeastern Arizona’s San Pedro River Basin in triple-digit heat for the annual wet/dry mapping of its water levels. A retired Army officer, he has volunteered annually to help the Nature Conservancy and its partners determine how the prolonged drought in the Southwest and the depletion of aquifers from local use affect the river.

Equipped with GPS technology, sturdy hiking boots and plenty of water, Mr. Mouras and more than 150 other volunteers will fan out to collect data along the more than 220 miles of the river basin, from its headwater streams in Mexico to the confluence with the Gila River near Winkelman, Ariz. The San Pedro’s tributary streams, some of which lie thousands of feet above the river and its valley, include the Babocomari River, Aravaipa Creek, Hot Springs Canyon, Ramsey Canyon and Los Fresnos in Mexico.

The Nature Conservancy

Conservationists, academic researchers, and wildlife and water managers use the data to assess long-term trends that guide water conservation efforts in Cochise County, the city of Sierra Vista, and nearby Fort Huachuca, home of the Army Intelligence Center and the Army Network Enterprise Technology Command.

In 2010 the mapping effort showed that water was flowing in just 37 percent of the San Pedro basin. Last year that number fell to 33 percent, and volunteers are eager to see what the flow rate will be this year. Other figures show that the overall regional aquifer level is declining, which suggests that a serious water problem could be developing for local residents and wildlife. The yearly mapping identifies sections of the river that need water flow most. Retiring water pumps and establishing conservative easements near the river over time allows more water to flow to bone-dry riverbeds.



This is the 14th consecutive year that the San Pedro has been wet/dry mapped. The Nature Conservancy has teamed up with the federal Bureau of Land Management, the Community Watershed Alliance of Benson, the Cascabel Working Group and conservation partners in Mexico for the annual effort. The mapping is accomplished during the hottest and driest time of the year and before the annual monsoon rain season.

The San Pedro is one of only two rivers that flow north from Mexico into the United States, and it is home to two-thirds of the avian species in the United States, including 100 species of breeding birds and 300 species of migrating birds. The yellow-billed cuckoo, vermillion flycatcher and the gray hawk nest along the river’s shady, forested banks during the summer after migrating in the spring from winter habitats in Central and South America. The San Pedro basin is also home to animal species including the coatimundi, a slender-nosed mammal in the raccoon family. While only a few feet deep and 20-foot wide in places, the river is vitally important to the survival of such wildlife.

“This desert river is an essential habitat because it serves as an oasis of shade and water for local wildlife and migratory birds,” said Holly Richter, director of conservation at the Arizona chapter of the Nature Conservancy.

In a parallel to the adopt-a-highway program, Mr. Mouras and his small team annually map the same portion of the river, beginning at Charleston Bridge and running up to Boston Mill, an abandoned late-1800’s-era ore site near Tombstone, Ariz. Volunteers return year after year to renew their relationship with the waterway and claim a stake in its future.

“I’m concerned about the status of our local environment,” Mr. Mouras said. “I want to protect this habitat for the birds.”

Ms. Richter said that projects like these engage citizen scientists and “get them invested,” “It’s one thing to talk about water conservation, but it’s another to be intimately knowledgeable about the river in your own backyard,” she said.