A seasonal groundwater model was developed to simulate fluxes and head distributions
with periodic boundary conditions within the San Pedro Riparian National Conservation
Area (SPRNCA) in southeastern Arizona. This model incorporated a seasonal approach
for the period 1940-1995. Two years were used to simulate streamflow, 1990 and 1995.
The model, as currently calibrated, does not accurately reproduce observed baseflow
conditions in the San Pedro River and simulates an exaggerated effect of retiring
irrigation within the SPRNCA. The model simulated increased baseflows while the
observed baseflows declined at the USGS Charleston stream gage, though increases in
baseflow contributions between Hereford Bridge and Lewis Springs have been reported.
The original (Corell, et al., 1996) model and the seasonal transient model suffer from
over- estimation of discharge from the floodplain aquifer to the San Pedro river, as well as
errors in the seasonal transient model's simulation of riparian ET, and seasonal variations
in stream conductance. These problems precluded the seasonal transient model from
replicating the observed baseflows in the San Pedro river at the Charleston bridge,
however, the results of the simulation are thought to be qualitatively indicative of changes
in the flow system resulting from the retirement of irrigated agriculture in the San Pedro
Riparian National Conservation Area. Possible sources for this problem include
replacement of irrigation stresses by the expansion of cones of depression more distant
from the river, overestimation of mountain front recharge, poor baseflow estimates and
evapotransipration calculations from the stream gages at Charleston and Palominas, and
the effects of a recently discovered silt -clay body that may dampen the speed of the rivers
response to changes in stress.
Additional efforts to re- calibrate the model, taking these areas into account, should
provide better simulated baseflow values of the observed data.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/615748 |
| Date | January 2000 |
| Creators | Sharma, Vandana, Nish, Robert D. Mac, Maddock, Thomas, III |
| Contributors | Department of Hydrology & Water Resources, The University of Arizona, Arizona Research Laboratory for Riparian Studies |
| Publisher | Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ) |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Technical Report |
| Source | Provided by the Department of Hydrology and Water Resources. |
| Rights | Copyright © Arizona Board of Regents |
| Relation | Technical Reports on Hydrology and Water Resources, No. 00-010 |
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