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Preliminary evaluation of the ground-water-flow system in the Twin Cities Metropolitan area, Minnesota

Water-Resources Investigations Report 82-44

Prepared in cooperation with the Metropolitan Council of the Twin Cities, Minnesota Department of Natural Resources, Minnesota Geological Survey
By:
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Abstract

A preliminary quasi-three-dimensional finite-difference ground-water-flow model of the seven-county Twin Cities Metropolitan area was constructed and used to evaluate parameter sensitivity and adequacy of available data. Fourteen geologic units that underlie the study area were grouped into nine hydr,bgeologic units and were incorporated into a five-layer model. The layers in the simulation model include the Mount SimonHinckley, Ironton-Galesville, Prairie du Chien-Jordan, and St. Peter aquifers, and the drift.

Sensitivity analyses were made for 19 parameter and boundary-condition specifications. Model results are -most sensitive to recharge and withdrawal rates and to hydrogeologic variations related to drift-filled bedrock valleys. Analyses of available data and results of steady-state simulations indicate that critical data needs for improving the simulation model include spatial and temporal variations in ground-water withdrawals and potentiometric levels, and hydraulic properties of drift filling or partly filling bedrock valleys.

Areal distribution of calcium, sodium, sulfate, and chloride concentrations were analyzed to provide information on the hydrologic and geochemical relationships between aquifers. Ground water is generally of the calcium magnesium bicarbonate type. Concentration of dissolved solids in water from the Jordan Sandstone and Mount Simon-Hinckley aquifer generally decreases from southwest to northeast across the study area. This decrease probably reflects differences in the quality of recharge water and geochemical processes within the aquifers, such as ion exchange.

Study Area

Additional publication details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Preliminary evaluation of the ground-water-flow system in the Twin Cities Metropolitan area, Minnesota
Series title:
Water-Resources Investigations Report
Series number:
82-44
Year Published:
1982
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
St. Paul, MN
Contributing office(s):
Minnesota Water Science Center
Description:
v, 65 p.
Country:
United States
State:
Minnesota
Other Geospatial:
Twin Cites Metropolitan area
Online Only (Y/N):
N
Additional Online Files (Y/N):
N