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Mapping the San Pedro © Holly Richter/The Nature Conservancy

"This is participatory science at its best. It connects people to this river in a real way."

-Holly Richter, The Nature Conservancy's Upper San Pedro River Program Director

12th Year of Mapping: More than 100 volunteers, conservationists and agency staff spent June 20, 2009 walking in groups that covered around 150 of the 170 miles of the San Pedro River, plus many of the river's key tributaries.

The goal? To map where the river is flowing and where it is not, and to provide insights into the health of this premier southwestern river system. 

The mapping, done annually since 1998, is a massive collaborative effort that involves:

• The Nature Conservancy
• U.S. Bureau of Land Management
• Community Watershed Alliance of Benson
• Friends of the San Pedro River 
• citizen volunteers
• Naturalia, a Mexican non-governmental organization
• BIDA, a Mexican non-governmental organization
• the Mexican park service - CONANP

"This is participatory science at its best. It connects people to this river in a real way," said Holly Richter, the Conservancy's Upper San Pedro River program director. "Many people do this year after year because they love this river."

River Mapping Provides Important Information

The Data: This year, 45 percent of the 150 river miles mapped had surface water flowing. Last year water was present in 39 percent of the 120 river miles mapped. (See the maps from 2009.) 

Mapping this river over time will provide insight into what might be the causes in fluctuation of flows — climate change, drought, groundwater or surface water withdrawals. The effort will also assess the habitat for beaver, fish and other aquatic organisms.

What's New: This year the mapping included several higher-elevation tributaries to the river as well as 30 miles in Mexico.

The Wildlife: Volunteers who walk or ride the river encounter a diverse array of wildlife species. This year's sitings included:

• Raptors — gray hawks, a pair of nesting Harris hawks, turkey vultures
• Songbirds —  vermillion flycatcher, common ground doves, roughwing swallows, summer tanager, Bell's vireo
• Other birds — great blue heron, Mexican mallards, great horned owls
• Mammals — Beaver sign, bear tracks (at the San Pedro River Preserve near Dudleyville), deer
• Reptiles — Mohave rattlesnake, frogs, toads. turtles 
• Fish — longfin dace (a native)