Preliminary evaluation of the ground-water-flow system in the Twin Cities Metropolitan area, Minnesota
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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
| 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 |
| DOI | 10.3133/wri8244 |
| 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 |
| Google Analytic Metrics | Metrics page |