Laserfiche WebLink
<br />FARMLANDS, PRIME AND UNIQUE <br /> <br />Affected Environment: There are no prime or unique farmlands involved in the <br />proposed action or the alternatives. <br /> <br />Environmental Consequences/Mitigation: There are no environmental consequences <br />to farmlands so no mitigation is needed. <br /> <br />FLOODPLAINS, WETLANDS & RIPARIAN ZONES (includes a fmding on Standard 2) <br /> <br />Affected Environment: The Arkansas River in this area can be described as an incised <br />large river system that is well confined within its banks and lacks much floodplain development. <br />Annual runoff increases stream velocities as water "stacks" rather than spreads out over a broad <br />valley. The nature of this stream type limits riparian vegetation development to a narrow band <br />found adjacent to the margins of the annual average high water mark. There is quick transition <br />to upland vegetation and those plant species found in the riparian vegetation band tend to be deep <br />rooted shrubs and trees that grow down to the elevation of the water table in late summer. <br />Wetland species requiring highly saturated fine soils are less common as the rock banks hold <br />limited fine textured soil or moisture during the growing season. East and west stream banks are <br />entirely different geology but both banks result in an incised stream channel. Public use down in <br />the channel is rather limited except for some boating in these confined settings without <br />developed access because the step nature of the river banks limits hiking. <br /> <br />Appendix A which is a: South Main Site Analvsis accurately describes the resource: "The <br />river and surrounding land has outstanding natural qualities and are generally undisturbed. <br />The river banks are steep and congested with overgrown trees, deadfall and brush. Past this <br />thick tangle of undergrowth, along the riparian corridor, the land becomes dry and dotted with <br />cactus, sagebrush and an occasional juniper tree. Access to the stream corridor, from the top of <br />the bank is currently very limited through the project area." <br /> <br />Additionally, there is wide variation between late season flow and peak runoff (on average <br />greater than a ten fold difference: see Hydrology section). This variation yields a rock-lined <br />low-flow channel separated from the shrub vegetation line established at higher water. Some of <br />the BLM west bank terrace (a glacial boulder fill terrace) has been disturbed and increasingly <br />more homes have been built on the river bank in the vicinity. <br /> <br />Environmental Consequences/Mitigation: The overriding consequences of the planned <br />project, including that portion on BLM, will be the breaks in continuity of riparian vegetation <br />along the river corridor from continual human disturbance because of trails, access points, etc. <br />Along a rocky incised channel, riparian vegetation has less necessity for stream bank stability <br />relative to other streams settings and is not always necessary for rivers to function without <br />erosion but, the riparian zone here is valuable habitat. The amount of wetland vegetation is <br />naturally limited in width so that even a small modification is a recognizable disturbance. 10- <br />stream structures placed for boating in incised channels are less likely to cause problems to <br />floodplain resources or river banks because high flow overtops the structures rather than being <br />