Laserfiche WebLink
Eastern San Joaquin Groundwater Basin Groundwater Management Plan <br />Northeastern San Joaquin County Section 2 <br />Groundwater Banking Authority 39 Hydrogeology <br />Table 2-1 Stratigraphic Column for San Joaquin County Hydrogeologic Description High permeability, unimportant to groundwater except as avenue for percolation. Moderate to locally high permeability, unconfined aquifers. Moderate permeability, unconfined aquifers. Generally low permeability, saturated environments, unconfined to confined. Moderate permeability, generally unconfined above Corcoran Clay, confined below. Moderate permeability, unconfined to locally semi-confined. Restricted perched bodies in some areas Moderate to high permeability, where “black sands” occur. Confined to unconfined. Saline west of Stockton. Low permeability. Saline in part. Essentially non-water bearing except along fractures & joints. Low permeability. Saline in Stockton area. Not considered significant in groundwater studies. Contains saline waters except where flushed in outcrop areas. Unimportant to freshwater basin except as possible contaminant source. Contains saline waters, unimportant to freshwater basin except as possible contaminant source. Unimportant to freshwater basin except as possible contaminant source. Rock Characteristics and Environment Continental unconsolidated gravel, course to medium sand deposited along present stream channels. Continental fan deposits-heterogeneous, discontinuous mixtures of gravel silt & clay. Continental fan and interfan material, locally some basin type. Lenticular gravel, sand, silt, & clay Continental basin equivalent of Laguna, Tulare, and younger formations. Clay, silt, & sand, organic in part. Continental semi-consolidated clay, sands, & gravel. Contains Corcoran Clay member. Continental, semi to unconsolidated silt, sands, & gravel poorly sorted, include Arroyo Seco gravel pediment of Mokelumne River area. Continental andesitic derivatives of silt, sand, & gravel & their indurated equivalents; tuff; Breccias; agglomerate. Continental to marine massive sandstone & shale. Westside equivalent to Merhten & Valley Springs formations, in part. Continental to marine rhyolitic ash, clay, sand, gravel & their induriated equivalents. Marine shale, siltstone, & sandstone. Marine shale, siltstone, & sandstone. Marine shale, sandstone, chert metamorphica, serpentine. Thickness (feet) 0 to 150± 0 to 150± 0 to 1400± 0 to 1400± 0 to 1000± 0 to 600± 0 to 1000± 7 to 500± ? ? ? Location Eastside & Westside Westside Eastside Eastside & Westside Westside Eastside Eastside Westside Eastside Westside Westside Westside Formation Stream Channel Deposits Alluvial Fan Deposits Recent Alluvium and Victor Flood Basin Deposits Tulare Laguna Merhten San Pablo Group Valley Springs Eocene Undifferentiated Cretaceous Undifferentiated Franciscan Group, Undifferentiated Series Recent Late to Pleistocene Plio-Pleistocene Mio-Pliocene Upper Miocene Miocene Eocene Cretaceous Jurassic Source: San Joaquin County Water Management Plan Volume II System Quaternary Tertiary Cretaceous Jurassic