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2007 Ground Water Summit |
Wednesday, May 2, 2007 : 3:00 p.m.
Coupled Groundwater/Surface Water Model for Evaluating the Hydrologic Effects of Albuquerque's San Juan-Chama Project
As a basis for granting diversion permits for use of ground or surface water in New Mexico, the New Mexico State Engineer (OSE) requires that water users quantify the hydrologic effects of proposed projects. In the case of groundwater projects, the effects of most interest are aquifer drawdowns, impacts on neighboring wells, possible water quality issues, and how pumping might induce added seepage from or reduce flow into surface streams. In the case of projects involving diversions of surface water, the major concerns are effects on streamflows and possible impacts on downstream water rights holders – especially during periods of low flow and drought. In the case of a conjunctive use project, such as Albuquerque Bernalillo County Water Utility Authority (Authority) San Juan-Chama Project, the evaluation of effects becomes more complicated, because of combined groundwater-surface water effects, the use of non-native (imported) water, and because wastewater return flows are involved. Return flows must be evaluated along with surface diversions, and pumping effects to ensure the State Engineer that the project has a positive overall water rights balance, and that the river is “kept whole.” The methodology used to address these issues for the San Juan-Chama Project was termed the AWRMS River Model. The model involved a coupling of the State Engineer’s Interim ground-water model of the Middle Rio Grande basin with a ‘spread-sheet’ surface water model. The ‘spread-sheet’ model used an adjusted record of 1971-98 monthly streamflows on the