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<br />, ' <br /> <br />SOILS (includes a finding on Standard 1) <br /> <br />Affected Environment: The soils on the upland area of the project area are described as <br />San Isabel stoney sandy loam, 1-5% slopes. The point where the steep slope drops into the <br />Arkanasas River drainage area, the soils are described as Dominson gravelly sandy loam, 9-45% <br />slope. San Isabel soils tend to be excessively drained soils on high terraces. They are shallow <br />over gravel and cobbles, having formed in gravelly moderately coarse textured outwash. <br />Permiability in the soil is rapid and the available water capacity is low. Effective rooting depth <br />is around 60 inches. Soil erosion is considered slight. The Dominson soils are narrow areas <br />along terrace edges and occur in nearly all parts of Chaffee County. They tend to be less than 11 <br />inches deep along the river corridor and in most places there is a larger amount of gravel and <br />cobbles on the surface. Surface runoff is rapid and the hazard of erosion is severe. <br /> <br />Environmental Consequences/Mitigation: The project area is small compared to the <br />entire length of the river. This analysis does not provide data to make a cumulative analysis of <br />similar river corridor disturbances occurring along the the entire length ofthe Arkansas River <br />from the headwaters to the Pueblo Reservoir. Some consideration was given to cumulative <br />impacts in the Arkansas River plan. Since the soils being impacted tend to be along narrow areas <br />following this corridor, this small project does add to other cumulative impacts ofthese types of <br />soils (removal of soils from functioning soils by hardening to prevent erosion). These soils <br />typically support the grass, shrub and tree communities common to the vegetation just above and <br />down the riparian zones in channalized river corridors. This and the other projects result in <br />hardened areas to prevent erosion that re-direct the natural water flows and slightly increases <br />total number of areas and likelyhood of additional soil ditch-type erosion along the corridor. <br /> <br />Impacts to soils from the project will result in slight increases in total sedimentation load into the <br />Arkansas River. Some new erosion cutting on the banks is likely. The highest risk of erosion <br />cutting problems will be during the construction phases and are dependent upon occurrence and <br />severity of precipitation events. The proposal speaks to measures of hardening (cement and <br />gravel) but does not specify a drainage plan for long term soil protection. <br /> <br />Mitigation suggested for this project should include a requirement for a short-term drainage plan <br />and long-term drainage monitoring plan. This plan should take into consideration re-directed <br />flows of water that will be collected in parking areas, roads, and trails; determination of the <br />potential water acculation during 5-10 years storm events; and the installation of such drainage <br />structures as necessary. The intent of these structures should be to divert water prior to large <br />accumulation into natural areas of well established vegetation as often as possible. In areas <br />where this is not possible, structures should be constructed to handle high flows of water while <br />minimizing cutting potential. A common structure used for this situation is rip-rapping such <br />areas with rock of 10 - 20 inch size along the water drainage area to the point where it empties <br />either on natural vegetation areas or into the river corridor. <br /> <br />Finding on the Public Land Health Standard for Upland Soils: The current status of <br />soils in the project area is that they are minimally meeting the health of the land guidelines. The <br />soils of the area are already currently impacted by some dispersed use of campers, fishermen, <br />and other recreational type uses. The project includes proposals to limit the areas that would be <br />