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Hydrology

Willcox Regional Model

The groundwater flow model of the Willcox Basin is a regional-scale MODFLOW 2005 model that was developed by ADWR and released in July of 2018. The model includes the major alluvial aquifers in the Willcox Basin (the upper and lower basin fill units), and the active model domain extends into portions of the Aravaipa and Douglas groundwater basins. The model was calibrated using manual and non-linear regression techniques and includes more than 2,500 head targets and four regional-scale groundwater discharge (flow) targets. The calibrated time frame is 1940 to 2015 and there is also a projection simulation from 2016 to 2115. The grid cell size is 1 mile by 1 mile and there are two stress periods per year to represent growing / non-growing seasons, as agriculture is the dominant water use in the basin. The model was independently peer-reviewed by the technical consulting firm S. S. Papadopulos and Associates prior to its publication. The 2018 model release included six different versions of the model with variable pumping and recharge rates. All six of these versions can be found in the "Model Files (All ACMs) link. To access the model version that is most described in the report (ACM1a), select the "Willcox Model 2018" link. Additionally, two geodatabases are provided: the Willcox 2018 GDB has a select set of shapefiles generated directly from the model files and is the ADWR-recommended geodatabase for public access. The "Model Files (All ACMs)" geodatabase contains files from multiple versions of the model.

Model Datasets

File Name Description Linked Files
Willcox 2018 GDB A new geodatabase is created from published GIS shapefiles and modified with references.
Willcox Model 2018 Included are simply modified model files identical to the 2018 release.
Model Files (All ACMs) Included are the pre-and-post processing files, as well as the PEST files. Model Files (All ACMs)
Shapefiles (All ACMs) Model shapefiles exported from model geodatabases

Model Reports and Documents

File Name Description Linked Files
Willcox Exec Summary
Willcox Model Report 2018

Questions

If you have any questions please contact the ADWR Modeling Unit.