Three Canyons Project
The Three Canyons Conservation Site is owned and managed by Cochise County, and the City of Sierra Vista holds a conservation easement on this 480-acre parcel that will permanently limit future groundwater pumping and development. In addition, the purchase of the property was originally funded by the U.S. Army and Fort Huachuca, making it a true collaborative effort. Historically, large capacity irrigation wells on the property pumped approximately 2,592 acre-feet of water each year. The 480-acre parcel saves another 36 acre-feet per year that will not be pumped due to precluded development. The San Pedro River’s flow is supported by groundwater much of the year, and nearby pumping can reduce the amount of groundwater that reaches the river. The permanent retirement of this pumping helps to not only protect San Pedro River flows, but also benefits the water levels in the wells of nearby residents in Palominas.
A private well located along the San Pedro River near this project tells an interesting story showing the impacts of pumping at Three Canyons from the mid-1990s through mid-2000s. After the pumping was retired in 2005, the groundwater levels rebounded to levels observed prior to 1996. More information about the science behind this groundwater response can be found here:
Cochise County is undertaking a flood control project on the 480 acres that will reduce rainfall runoff and the contaminants it carries. It will utilize regenerative agriculture practices to achieve the above flood control objectives and be monitored to quantify reduced runoff, sediment and e-coli and increased soil moisture infiltration and carbon sequestration. Plant health and diversity will be monitored as well and ongoing groundwater monitoring is also conducted by the U.S. Geological Survey (USGS) there, and the groundwater data can be found here.
Monitoring data will also be used to compare decentralized, watershed management with centralized, infrastructure-intense flood control methods for effectiveness vs. cost.