WSP05700

• File Number: 8278.400
• Description: Title I - Mexican Treaty
• Basin: Colorado Mainstem
• Date: 2/17/1973
• Author: IWBC by Harshbager
• Title: Memorandum Report MR-73-1 Appendices, A - Groundwater Conditions in the Colorado River Delta Area, United States and Mexico and Appendix B - Pumping Regimens, Effects and Prediction Analysis
• Water Supply Pro - Doc Type: Publication

APPENDIX B

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PillIPING REGINENS ,EFFECTS, AND PREDICTION ANALYSIS

INTRODUCTION

In order to assess the effects of pumping from wells now
installed and proposed well field plans in Nexico and United
States, a series of analog model runs have been conducted by the
U. S. Geological Survey Analog ~lodel Laboratory, Phoenix, Arizona.
The singular effects for each existing and proposed pumping
regimen in United States and Nexico have been studied. Pertinent
aspects of these results are reviewed in this Appendix B.

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,Specifically, the study was to determine the effects of
1) United States groundwater pumpage and 2) !--lexican groundwater
pumpage, on the magnitude and direetion of underground flol.s
across the international boundary in the limitrophe section of
the Colorado River and in the Arizona-Sonora boundary seetion
(Figure B-1).

Description of Electric Analog Hodel

The geologic and hydrologic features of the groundwater basin
have been modeled in an electric analog eovering about
2,860 square miles at scales ranging from one node equals
1,500 feet to one node equals 6,000 feet and ineludes a total
of 16,500 nodes. Two resi stor-capaei tor networl(s are inter-
connected at corresponding nodes by resistors that represent
the average vertical permeability and distance along the flo1{
path between the wedge and coarse-gravel aquifers. For the
current model, the upper layer of fine-grained sediments
(shallow aquifer) in the Yuma Vallcy has been simulated with a