Modeling of stream aquifer interaction in lower Cienega Creek basin using a finite element technique

Digitized from paper copies provided by the Department of Hydrology & Atmospheric Sciences

STREAM-AQUIFER INTERACTION MODELING IN LOWER CIENEGA CREEK BASIN, ARIZONA USING FINITE ELEMENTS

Only a few areas in the deserts of the southwestern United States possess perennial streamflows. Cienega Creek near Tucson, Arizona is one of them (Figurel). Because of ground -water punping, some of these streams are in jeopardy of becoming ephemeral. The variability of surface water supply in the southwestern United States is very important because of its effects on riparian systems. Declines in water table and ground -water storage (over - exploitation of pumping wells) pose major concern as land subsidence and earth fissures, and produce stream and vegetation losses through ground and surface -water interactions. This report examines the Lower Cienega Creek Basin (LCCB) and the potential impact of nearby commercial development on the perennial stream. This area was chosen because it contains a natural preserve and a perennial stream. Perennial water flow and shallow water levels along the creek support various riparian species which shelter many types of insects and wildlife. The stream contained several species of fish including the endangered Gila Topminnow before they were extinct from this creek. This natural preserve, near the basin's exit, is one of the few desert places in the U.S. supporting a suitable habitat for animals, birds, and fishes because of its lush vegetation. An important riparian indicator for water table levels are cottonwood trees. These trees require shallow water to survive. As water levels decline, the cottonwoods produce less leaves. These cottonwoods could limit their existence by ceasing reproduction. Ultimately, a detrimental impact will be noticed in the surrounding ecosystem.During the Fall semester 1993, the Department of Hydrology and Water Resources initiated a thesis practicum allowing students to complete a Master's thesis within a year by participating in a group project. The project is divided topically, with each student in charge of a specific topic, resulting in a thesis and a HWR Series report. The group project covers each of the departmental focal areas: surface -water hydrology, subsurface hydrology, water chemistry, and water resources administration. This report is based on a thesis from the Fall 1993 - Spring 1994 project focusing on the water resources of the Lower Cienega Creek Basin, Arizona. This basin encompasses Pima Count's Cienega Creek Natural Preserve, located about 25 miles southeast of Tucson. The basin includes perennial stream reaches at the "Narrows" and within the preserve. These flows support a lush riparian population, one of the few remaining in the state. The goals of this project were tp provide insight into hydrological processes with in the basin and to recommend management alternatives. The following are faculty participants: Nathan Bums Leo Leonhart Martha Conklin Tom Maddock III Don Davis L. G. Wilson Simon InceThis title from the Hydrology & Water Resources Technical Reports collection is made available by the Department of Hydrology & Atmospheric Sciences and the University Libraries, University of Arizona. If you have questions about titles in this collection, please contact [email protected]