05-06-13 Council Packet - Laserfiche WebLink

Home Search

City of Lino Lakes SWMP | February 8, 2013 Draft | 15 3.6. So ils The City of Lino Lakes is located within the Anoka Sandplain ecological subsection of central Minnesota. The Anoka Sandplain is a 1,875 square mile glacial outwash plain that includes portions of 13 Minnesota counties, and is centered on most of Anoka, Isanti, and Sherburne counties. The Anoka Sandplain was created and shaped by the last major glacial episode in Minnesota – the Wisconsin glaciation – between 35,000 and 10,000 years ago. The City of Lino Lakes is located within the historic lake bottom of Glacial Lake Fridley which formed from glacial ice -melt water circa 12,000 years ago. The release of glacial melt water from Glacial Lake Fridley created deep, broad, irregular troughs within the glacial lake bottom. These troughs formed the Rice Creek Chain of Lakes and associated wetland complexes of present day, as well as numerous other lake chains to the northwest and southeast of Lino Lakes. The glacial history of Lino Lakes resulted in complex patterns of surficial geology, hydrology, and soil ass ociations that remain as important influences on development, agricultural patterns, and natural resources conservation opportunities within the City . The upland soils of Lino Lakes are typically sandy, moderately to well drained, and nutrient poor. Wetlan d soils are typically shallow to deep organic peat deposits over sand or saturated sands, which occur within complex networks of braided depressions throughout the City ’s landscape. The southeastern most edge of the City includes a small portion of a glaci al till. The upland and wetland soils of this landscape inclusion are comprised of fine -textured silt loams, loams, and cla ys that are poorly drained. Topography throughout the City is generally flat to slightly undulating, and the regional groundwater tab le is typically shallow below the soil surface. Soil types commonly found in Lino Lakes have been grouped into categories (as illustrated in Figure 5 ) based on the H ydrologic S oil G roup (HSG), or runoff potential from precipitation. This classification describes the hydrologic features of the soils and is derived from vegetation, soils composition, and slope. Combined hydrologic soil groups (e.g. A/D, B/D, and C/D) r epresent soils that can be classified by two labels depending on their drained status. The first letter indicates the soil’s properties in a drained setting and the second letter indicates that same soil’s properties in an undrained area. Table 3 summarizes the four hydrologic soil groups: Table 3 . Soil hydrologic groups Hydrologic Soil Group (HSG) Description A Soils having high infiltration rates when thoroughly wet (low runoff potential). Deep, well drained to excessively drained sand or gravelly sand. B Soils having a moderate infiltration rate when thoroughly wet. Moderately deep or deep, moderately well drained or well drained with moderately to moderately coarse texture. C Soils having a slow infiltration rate when thoroughly wet. Soils have a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. D Soils having ve ry slow rates of infiltration when thoroughly wet (high runoff potential). Soils consists of clays with high shrink -swell potential, soils have a permanent high water table, soils that have a claypan or clay layer at or near the surface and soils that are shallow over nearly impervious materials. Urban Land Areas of development that are covered by asphalt, concrete, and buildings. Data from Natural Resource Conservation Service , 1977.