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Table 9 — Bedrock Aquifers <br />Geologic <br />Formatio <br />Age <br />Primary <br />ydrogeologi <br />Designation <br />pproxima <br />Thicknes <br />Primary Regional Lithology <br />Hinckley <br />Sandstone <br />Pre- <br />Cambrian <br />Aquifer <br />q <br />Not Available <br />Quartzose sandstone overlying the <br />Precambrian bedrock <br />Mt Simon <br />Sandstone <br />Middle <br />Cambrian <br />Aquifer <br />—200 to 336 <br />ft <br />Quartz sandstone that contains <br />interbedded siltstone and very fine <br />sand. <br />Eau Claire <br />Formation <br />Middle to <br />Upper <br />Cambrian <br />Confining <br />—60 to 90 ft <br />Fine grained sandstone, siltstone and <br />shale. <br />Wonewoc <br />Sandstone <br />Upper <br />Cambrian <br />Aquifer <br />q <br />50 to 60 ft <br />Very fine to very coarse grained <br />Sandstone. <br />Tunnel CityUpper <br />Group <br />pp <br />Cambrian <br />Aquifer / <br />q <br />Confining <br />150 to 180 <br />ft <br />Lower is massively bedded very fine <br />to fine-grained sandstone; upper is <br />coarse grained sandstone. <br />St <br />Lawrence <br />Formation <br />Upper <br />b <br />Cambrian <br />Confining <br />— 38 to 59 ft <br />Dolomitic siltstone with interbedded <br />very fine-grained sandstone and <br />shale. <br />Jordan <br />Sandstone <br />Upper <br />Cambrian <br />A uifer <br />q <br />85 to 100 ft <br />Upward sequence of fine to coarser <br />grained sandstone. <br />5.1.2.1 <br />5.1.2.2 <br />Regionally other bedrock aquifers exist that are not listed above, the following are aquifers <br />present within the City of Ramsey area. These aquifers are discussed in detail in the following <br />sections. Throughout the City of Ramsey, The Tunnel City group is the uppermost Bedrock unit <br />meaning the St Lawrence and Jordan Sandstone is only sparsely present. Above these Bedrock <br />units are unconsolidated sediment discussed in sections above. <br />Jordan Aquifer <br />The Jordan Aquifer is generally considered to be hydrologically connected to the Prairie Du <br />Chien Unit. However, as evident from the geologic bedrock map (Figure 2 in Appendix D) the <br />Prairie Du Chien Unit was either not deposited or has been entirely eroded through much of this <br />area. The thickness and presence of this aquifer through this area is scarce and laterally <br />disconnected. Where present, Within the City of Ramsey, the Jordan Sandstone thickness is <br />minimal at around 20-30 feet and appears heavily eroded. Quaternary deposits directly overlay <br />this unit and the Jordan Sandstone is likely recharged by these deposits. <br />Wonewoc / Tunnel City Group <br />The Tunnel City Group and the underlying Wonewoc Sandstone (formerly known as the <br />Franconia -Ironton -Galesville Aquifer) supply water for much of the Northwest Metro region. <br />Presence and thickness of the Tunnel City is depicted on Figure 6 in Appendix D, and for the <br />Wonewoc on Figure 8 in Appendix D. Areas where the Aquifer is not present primarily occur <br />within bedrock valleys where previous streams and surface water features carved away the <br />bedrock unit. A large unconformity of the Wonewoc Sandstone is depicted within Anoka County <br />where heavy erosion of this unit appears to have taken place prior to the deposition of the Tunnel <br />City Aquifer. This area is depicted where the Wonewoc aquifer thickness thins or is not present <br />FEASIBILITY STUDY RAMSY 154354 <br />Page 15 <br />