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its confluence with Hubberson Gulch, which is a 114% increase over the <br />baseline average (1,048 mg/I). <br />The increase in TDS in Dry Creek should not preclude use of the water <br />from any of its current uses, since current uses do not include domestic use <br />or flood irrigation. <br />I V. Topsoil <br />Soil resource information is provided in Tab 9, Volume 5 of the permit <br />application. Information on topsoil handling, maintenance and testing is <br />contained in Tab 21, Volume 13. The PR #1 submittal extensively reorganized <br />the soils sections of the application and updated the soil baseline information to <br />reflect 1990 survey of portions of the north mine area which had not previously <br />been surveyed. <br />The permit area is occupied by three soil orders; Mollisols, Entisols, and <br />Aridisols. The presence of these three orders is characteristic of the soils found <br />in steep, semi-arid regions of Northwestern Colorado. These orders represent <br />soils that grade from recently developed soils with minimum horizon <br />development to more developed soils with well developed diagnostic horizons. <br />Specific soil types within these orders occur on predominantly three types of <br />parent material-land form combinations, namely: 1) upper side slopes, ridges, <br />and swales of sandstone residuum; 2) toe slopes, side slopes, rounded ridge tops <br />of shale residuum and colluvium; and 3) toe slopes, side slopes, ridges, and <br />escarpments of sandstone and shale. Among the 22 soil types occurring within <br />the permit area, major topsoil salvage limitations include clay textures, high <br />coarse fragment content, steep slopes, shallow bedrock, salinity, and alkalinity. <br />Seneca Coal Company strips topsoil in single lifts once the woody vegetation <br />which would interfere with handling of the topsoil has been removed, pursuant to <br />4.06.2(1). Topsoil will be redistributed immediately on regraded areas when <br />possible or stockpiled in designated storage areas pursuant to 4.06.1(2). The <br />amount to be stockpiled depends on pit advance, season of the year, and <br />reclamation activities taking place at the time of salvage. Stockpiled topsoil is <br />placed in stable areas and protected from wind and water erosion by planting of <br />aquick-growing vegetative cover. Single lift stripping mixes different soil <br />horizons and thereby dilutes heavy clay concentrations encountered in various <br />subsoils. Although soil survey information and soil handling plans contained in <br />the PR #1 application were detailed and comprehensive, several issues of <br />concern were raised during the adequacy review. <br />The Division questioned what field characteristics would be used to define <br />appropriate salvage depths and requested justification for complete or partial <br />salvage variances proposed for a number of soil map units. Seneca provided <br />appropriate detail in regard to field salvage depth determinations. Generally, in <br />31 <br />