What did the San Pedro River look like 150 years ago? A look at the St. David Cienega might give you a good idea.
A Cienega ("see-en-e-ga") is a marsh or wetland. Cienegas can form where layers of rock or impervious clay hold water at the surface or through the continuous upwelling of numerous small springs and seeps. These conditions produce a rare plant community of sedges, grasses, reeds, and cattails because the soil is permanently saturated. This habitat supports a diversity of interesting plants, birds, insects, amphibians, reptiles, and mammals.
Before extensive human settlement in the area, the San Pedro was a system of cienegas maintained primarily by the thousands of beaver that lived along the river. Removal of the beaver in the mid to late 1800's, increased land use and excessive removal of vegetation caused the river to channelize and down cut in a relatively short period of time.
While the St. David Cienega is not part of the San Pedro River, it is a small remnant of the extensive wetlands that once were here. It occupies a low depression of approximately 100 acres one half mile west of the San Pedro River (and an equal distance to the southeast of the parking area).
Other floodplain wetlands were altered or lost due to intensive farming and ranching and construction of roads and railroads. They were often drained to create productive agricultural fields. Most of the remaining cienegas disappeared as the water table that once sustained them receded.
The St. David Cienega, designated as a Research Natural Area (RNA), is now protected within theSan Pedro Riparian National Conservation Area. RNA's are managed to keep human impacts to a minimum. Please do not camp here or leave any evidence of your visit. Help us protect this small example of our nation's natural heritage.
Directions: To reach the cienega, take HWY 80 west from St. David to Apache Powder Rd. Turn south and continue past the Apache Powder Plant and onto the improved dirt portion of the road. After the road curves to the east, go right immediately after crossing the railroad tracks. The parking area is about a mile past this point.
San Pedro Riparian National Conservation Area
4070 South Avenida Saracino
Hereford, AZ 85615
Manager: Vi Hillman
3201 E. Universal Way
Tucson, AZ 85756
Phone: (520) 258-7200