GROUND WATER ATLAS of the UNITED STATES
Iowa, Michigan, Minnesota, Wisconsin
HA 730-J

Cambrian-Ordovician aquifer system

(figures 97-132)

---

Introduction (Click to view thumbnails and download figures)

• Figure 97 Map showing location of the Cambrian-Ordovician aquifer system
• Figure 98 Correlation chart providing information about the Cambrian-Ordovician aquifer system

Hydrogeologic Units (Click to view thumbnails and download figures)

Maquoketa Confining Unit

• Figure 99 Map showing location of Maquoketa confining unit
• Figure 100 Correlation chart providing information about the Maquoketa and St. Lawrence-Franconia confining units and the St. Peter-Prairie du Chien-Jordan aquifer

St. Peter-Prairie du Chien-Jordan Aquifer

• Figure 101 Map showing location of the St. Peter-Prairie du Chien-Jordan aquifer
• Figure 102 Map showing location of the St. Peter Sandstone
• Figure 103 Photograph showing an example of St. Peter Sandstone
• Figure 104 Map showing stratigraphic units on which the St. Peter Sandstone was deposited
• Figure 105 Map showing thickness of the St. Peter Sandstone
• Figure 106 Photograph showing dolomite from the Prairie du Chien Group
• Figure 107 Map showing location if the Prairie du Chien Group
• Figure 108 Map showing location of the Jordan Sandstone
• Figure 109 Map showing thickness of the Jordan Sandstone

St. Lawrence-Franconia Confining Unit

• Figure 110 Correlation chart providing information about the St. Lawrence-Franconia and Eau Claire confining units and the Ironton-Galesville aquifer

Ironton-Galesville Aquifer

• Figure 111 Map showing location if the Ironton-Galesville aquifer
• Figure 112 Generalized vertical section across the Hollandale Embayment showing placement of the Ironton-Galesville aquifer

Eau Claire Confining Unit

Mount Simon Aquifer

• Figure 113 Correlation chart providing information about the Eau Claire confining unit and the Mount Simon and crystalline-rock aquifers
• Figure 114 Map showing location if the Mount Simon Aquifer
• Figure 115 Map showing thickness of the Mount Simon Aquifer

Ground-water Flow (Click to view thumbnails and download figures)

• Figure 116 Map showing horizontal ground-water movement in St. Peter-Prairie du Chien-Jordan aquifer
• Figure 117 Map showing vertical ground-water movement in southeastern Minnesota
• Table 6 Table showing transmissivity values in the St. Peter-Prairie du Chien-Jordan aquifer
• Figure 118 Map showing transmissivity of the St. Peter-Prairie du Chien-Jordan aquifer in Iowa
• Figure 119 Diagram showing how transmissivity and confinement affect aquifer water levels
• Figure 120 Diagram showing estimates of principal inflow and outflow of water in the St. Peter-Prairie du Chien-Jordan aquifer
• Figure 121 Map showing the predevelopment potentiometric surface of the St. Peter-Prairie du Chien-Jordan aquifer in Iowa
• Figure 122 Map showing the 1974-1975 potentiometric surface of the St. Peter-Prairie du Chien-Jordan aquifer in Iowa
• Figure 123 Map showing the decline of the potentiometric surface of the St. Peter-Prairie du Chien-Jordan aquifer in Iowa
• Figure 124 Hydrographs of wells completed in the St. Peter-Prairie du Chien-Jordan aquifer in Iowa
• Figure 125 Map showing the water level decline in the Cambrian-Ordovician aquifer system in the Milwaukee-Chicago area
• Figure 126 Map showing potentiometric surface of the Ironton-Galesville aquifer in 1980
• Table 7 Table showing transmissivity values in several Cambrian-Ordovician aquifers
• Table 8 Table showing comparison of water-level altitudes in several Cambrian-Ordovician aquifers
• Figure 127 Map showing potentiometric surfaces of the Mount Simon aquifer for 1980
• Table 9 Table showing transmissivity values for the Mount Simon aquifer

Ground-water Quality (Click to view thumbnails and download figures)

• Figure 128 Map showing dissolved solids concentrations in water from the St. Peter-Prairie du Chien-Jordan aquifer
• Figure 129 Map showing chloride concentrations in water from the St. Peter-Prairie du Chien-Jordan and Mt. Simon aquifers
• Figure 130 Map showing sulfate concentrations in water from the St. Peter-Prairie du Chien-Jordan and Mt. Simon aquifers
• Table 10 Table showing a summary of common anion-cation concentrations in water from the St. Peter-Prairie du Chien-Jordan aquifer
• Figure 131 Map showing dissolved solids concentrations in water from the Mount Simon aquifer

Fresh Ground-water Withdrawals (Click to view thumbnails and download figures)

• Figure 132 Pie charts showing use of fresh ground-water withdrawals by State

Return to HA 730-J table of contents
Return to Ground Water Atlas home page