Hydrologic monitoring in the Upper San Pedro Basin begins at the U.S. Geological Survey (USGS) Charleston stream gauge. However, the data are not comparable to today's data until May 1, 1935 when the gauge was moved near to its current location. Charleston Gauge Supplemental History
1953: The USDA Agricultural Research Service
establishes the Walnut Gulch Experimental Watershed and begins collecting precipitation data to increase understanding of precipitation in rangeland watersheds, like those surrounding the San Pedro River, and later adds runoff, evapotranspiration, and groundwater recharge monitoring.
The United States Congress establishes the San Pedro Riparian National Conservation Area (SPRNCA) to protect the riparian area and the aquatic, wildlife, archeological, paleontological, scientific, cultural, educational, and recreational resources of the public lands surrounding the San Pedro River. Public Law 100-696, “The Arizona-Idaho Conservation Act of 1988”
The Upper San Pedro Partnership (USPP) is established through the Arizona Department of Water Resources Rural Watershed Initiative with 21 member agencies and organizations representing Federal, State, and local governmental and nongovernmental entities.
U.S. Defense Authorization Act of 2004 recognizes the USPP as a collaborative water use management program working together to meet the long-term water needs of the Sierra Vista Subwatershed by achieving sustainable yield of the regional aquifer, to preserve the SPRNCA, and ensure the long-term viability of Fort Huachuca. “321 Public Law”
The Charleston streamflow gauge registers zero-flow for the first time in the 100 years that streamflow had been monitored near that reach of the San Pedro River.
USGS Scientific Investigations Report (SIR) 2005-5163, funded by the USPP, quantifies how much water the riparian habitat needs and uses, divides SPRNCA into 14 reaches, and established a condition class framework to track how each reach changes over time.
The groundwater flow model (USGS SIR 2006-5228), funded and collaboratively developed by the USPP, is completed by the USGS for the Upper San Pedro Basin and begins to be used by regional stakeholders for water management and planning to understand how to balance water needs and uses.
Based on previous USPP hydrological monitoring and reporting, the overall framework for the WHIP, including underlying hydrological monitoring programs by local, state and federal partners and indicators of sustainability, was established by the USGS and USPP, as published in USGS SIR 2016-5114
Launch of the Web-based Hydrologic Information Portal (WHIP) for the Upper San Pedro Basin.
Local communities, Fort Huachuca, and the San Pedro Riparian National Conservation Area (SPRNCA) all rely on limited groundwater resources as their sole, shared source of water within the Upper San Pedro Basin. In 1998, 21 agencies and organizations came together as a consortium, called the Upper San Pedro Partnership, and works together to meet the long-term water needs of the Sierra Vista Subwatershed, which is a distinct groundwater basin located within the Upper San Pedro Basin. In 2003, the partners agreed upon a goal of achieving sustainable yield of the regional aquifer to preserve the SPRNCA and ensure the long-term viability of Fort Huachuca. In 2019, the purpose of the Partnership was updated to more specifically “coordinate and cooperate in the identification, development and utilization of science and technical information to assist in meeting water needs in the Sierra Vista Subwatershed of the Upper San Pedro Basin.” As highlighted in the above timeline, since its inception, the Upper San Pedro Partnership has supported numerous hydrologic research and monitoring programs both within the Sierra Vista Subwatershed and the larger Upper San Pedro Basin.