AFFECTED ENVIRONMENT and ENVIRONMENTAL CONSEQUENCES Introduction the Affected Environment Describes Aspects of the Environment in and Near the Project Area

Chapter 3 - Affected Environment & Environmental Consequences CHAPTER 3 – AFFECTED ENVIRONMENT AND ENVIRONMENTAL CONSEQUENCES Introduction The Affected Environment describes aspects of the environment in and near the Project Area. It focuses on the physical, biological and social conditions that may be affected by implementation of the Proposed Action and No Action Alternatives. Familiarity with the Affected Environment is essential to understanding the Proposed Action and the potential environmental consequences. The Environmental Consequences disclose the impacts of implementing each of the alternatives. The consequences are directly related to the resource elements described in the Affected Environment About the Project Area The St. Vrain Project Area occurs within the North St. Vrain Geographic Area and Middle St. Vrain Geographic Area, located in the northeastern part of the Boulder Ranger District in Boulder County, Colorado (see Project Area Map). The Project Area spans 36,590 acres, with 22,725 acres managed by the USDA Forest Service and 13,865 non-National Forest System lands. The Project Area extends from an elevation of approximately 5,600 feet near Peak-to-Peak Highway (State Highway 7) close to Lyons to 9,331 feet near the Ironclads southwest of Allenspark. Most of the area is in the forested montane climatic zone and features the Middle and North St.Vrain Rivers with steep canyon walls and talus slopes, narrow valley bottom with a cascading high gradient stream channel and small areas of flood plain. Forested ridge-tops and hill-slopes occur outside these areas. The vegetation contains a mix of foothills and montane plant communities composed of ponderosa pine, lodgepole pine, limber pine, Douglas-fir, aspen, grassy meadows and hillsides, shrublands, rock outcrops, willow carrs and other riparian communities. Primary access is the Peak-to-Peak Highway (State Highway 7). State Highway 7 is a National and State Scenic and Historic Byway, traversing 55 miles from Estes Park in the north to US Highway 6 in the south. State Highway 7 bisects most of the Project Area, and is managed primarily to accommodate recreation-oriented traffic. SOILS Affected Environment Generally, the St. Vrain Project Area soils occurring on forested hill-slopes and ridge-tops (uplands) are shallow and rocky. Additionally, they have thin surface layers, and low water and nutrient holding capability. These sites are not usually highly susceptible to deep compaction but they have high potential for erosion if protective ground cover is removed and are particularly susceptible to loss of productivity if the organic (dark) portion of the surface layer is St. Vrain Fuels Reduction Project Environmental Assessment 3-1 Chapter 3 - Affected Environment & Environmental Consequences displaced or removed. Riparian area soils and vegetation are highly susceptible to damage caused by operation of heavy equipment or other vehicular traffic. A full description of project area soils, their properties, capabilities, limitations, and predicted response to the proposed management activities is contained in the affected environment section of the St. Vrain Soil Resources Specialist Report. Existing Condition of Project Area Soil Resources Ground cover was high (commonly above 90%) within proposed treatment areas and occurrences of active uplands erosion was low except for roads and other highly disturbed sites. This is because proposed treatment units are usually in areas where tree density is high, providing adequate needle-cast. There have been few past timber management activities in the SVPA and detrimental compaction was generally limited to highly disturbed sites such as roads, mines, etc. Soil mapping indicates the surface horizon is generally thin and has a sandy-loam texture. Sub-soils are generally rocky and rock outcrops are common. Past debris flows, possibly associated with post fire runoff, were also observed but other forms of mass wasting (landslides, slumps, etc) were not. Adequate amounts of large downed wood and slash, providing for nutrient cycling, were present in most areas. A range of decay classes of large downed wood was present but highly decomposed wood was not common. Expansion of user created travel routes in the Johnny Park and Bunce School Road areas has impacted soil and watershed resources. Removal of protective ground cover, erosion, compaction, and diversion and concentration of overland flow are commonly occurring on the existing and expanding road and trail network. Several trails in and adjacent to Unit 7 are also in an entrenched and eroding condition. Horse riding and hiking is the main activity on those trails. Soil Sensitivity and Limitations Soil sensitivity to disturbance (soil potential for erosion, compaction, displacement or impairment of nutrient cycling) is influenced by soil type and properties. Re-vegetation and recovery from disturbance depends on soil type, climatic conditions and the severity of the disturbance. Following soil disturbance, natural re-vegetation and recovery is a slow and difficult process in uplands soils of the St. Vrain Project Area, particularly on dry south-facing slopes. Additionally, wetland soils are highly susceptible to disturbance, difficult to manipulate, and present special problems for re-vegetation. Due to the resilient nature of soils, disturbance commonly lowers, but does not permanently destroy, site productivity. Environmental Consequences Environmental impacts to soil resources are assessed according to their effect on long-term soil productivity and soil hydrologic function. Soil is a highly variable and complex medium that serves to support plant growth and ecosystem diversity. Soil also functions as a “sponge and filter”, affecting watershed hydrologic response, water quality and stream channel health. Impacts to soil resources are described by the degree and extent of erosion, compaction, displacement, and impacts to nutrient cycling within designated activity areas (See Soils Specialist Report for more information.) St. Vrain Fuels Reduction Project Environmental Assessment 3-2 Chapter 3 - Affected Environment & Environmental Consequences Direct and Indirect Effects of Alternative A, No Action There are no known direct effects to the soil resources that would occur. Natural recovery of previously impacted areas would continue. Litter and large downed woody material would continue to accumulate and decompose at current rates. The extensive road and off-highway vehicle (OHV) trail network may be affecting soil productivity and watershed function, particularly in the Johnny Park and Bunce School areas. OHV activity is likely to remain at current levels or increase, which may lead to additional erosion, compaction, and sedimentation. In the absence of wildfire, coarse and fine downed fuels would continue to accumulate and stand density may increase over time. In the event of a wildfire, the hazard for a large higher intensity and severity burn is greater (Elliot and Robichaud, 2001). However, high intensity or severity fire may occur regardless of treatment, when extreme conditions of low fuel moistures and high winds occur (Graham, 2003; p11). Also, wildfires typically result in a mosaic of burn severities with a relatively low percentage of severely burned ground. If a large high severity fire were to occur, there would be a risk of severe erosion due to removal of large areas of protective ground cover and reduction of needle cast potential. In severely burned areas, consumption of litter, duff, large downed woody material and volatilization of soil humus and associated plant available nutrients would detrimentally impact site productivity. Removal of canopy and protective ground cover, and formation of hydrophobic soils by high severity wildfire can alter watershed response to rainfall events. If a significant proportion of the watershed is affected, increased up-land erosion, run-off, sediment delivery to stream channels, and in-channel erosion are likely. A large high severity fire would increase flood hazard and increase the risk of detrimental impacts to aquatic resources, beneficial uses of water, and other downstream values. Following wildfire, the probability of mass wasting, particularly debris flows, would also increase. Reduction of vegetation increases soil moisture because evapo- transpiration is reduced. Large-scale reduction of vegetation through large wildfires can increase soil moisture and shallow ground water to the point where mass failure potential also increases. However, slope failure of this kind is unlikely in the Project Area due to rapidly draining soils and low average annual precipitation. Cumulative Effects of Alternative A, the No Action No additional direct soil impacts would result from project implementation. Past measurable detrimental impacts to soils associated with wildfires, historic mining, timber harvest, dispersed camping, and OHV use would still exist on the landscape. Natural recovery of previously compacted or eroded areas would continue. Based on field reconnaissance, review of aerial photography and limited management activities in the past 20 years, the extent of past detrimental impacts to soil resources is estimated to be low for project activity areas. If the project were not implemented, recovery of impacted areas would continue at current rates. St. Vrain Fuels Reduction Project Environmental Assessment 3-3 Chapter 3 - Affected Environment & Environmental Consequences Direct and Indirect Effects of Alternative

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