ARS | Publication request: DETERMINING THE RIPARIAN GROUND-WATER USE WITHIN THE SAN PEDRO RIPARIAN NATIONAL CONSERVATION AREA AND THE SIERRA VISTA SUBWATERSHED ARIZONA

Submitted to: United States Geological Survey Water Supply
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2004
Publication Date: May 1, 2006
Citation: Scott, R.L., Williams, D., Goodrich, D.C., Cable, W.L., Levick, L.R., Mcguire, R.R., Gazal, R., Yepez, E.A., Elsworth, P., Huxman, T.E. 2006. Determining the riparian ground-water use within the San Pedro Rparian National Conservation Area and the Sierra Vista subwatershed Aizona. In Hydrologic Requirements of and Consumptive Ground-Water Use by Riparian Vegetation along the San Pedro River, Arizona, U.S. Geological Survey Scientific Investigations Report 2005-5163 (eds Leenhouts JM, Stromberg JC, Scott RL), pp. 107-142.

Interpretive Summary: For many of the human settlements in the Southwest, groundwater from regional aquifers has become the largest single source of fresh water for human communities. This reliance on groundwater has led to a large effort to further our understanding of the water balance of these large regional groundwater systems. A critical component of this water balance is amount of water used by the riparian system. A multiyear, multidisciplinary research effort was made to improve estimates of riparian vegetation water use for a federally protected portion of the Upper San Pedro River. Significant improvements were made in the measurement of water use by key riparian ecosystems. This information was combined with a vegetation map to make the most accurate estimates of riparian water use to date. This information will be used by a consortium of federal, state and local entities in the San Pedro basin to better understand the water balance of the basin's main aquifer.

Technical Abstract: The purpose of this portion of the Water Needs Study is to provide improved estimates of groundwater, or consumptive, use by the riparian vegetation within the San Pedro Riparian National Conservation Area (SPRNCA). Such knowledge will enhance understanding of the riparian evapotranspiration (ET) and the role of riparian vegetation groundwater use in the Upper San Pedro Basin water budget. Our approach was to make new, direct measurements of ET from dominant ecosystem types within the SPRNCA that are the principal components of the riparian groundwater demand. Coupled with these measurements of ET, we also studied how ET was partitioned into surface or groundwater sources. We then combine these revised and refined estimates of ecosystem water use with a new vegetation map of the SPRNCA to extrapolate the local measurements to the entire SPRNCA for estimates of total riparian corridor groundwater use.