WSP03331 - Laserfiche WebLink

Home Browse Search

nQ1G4o Affected environment & Consequences 3-34 3.8.2 Alternative A No changes are projected under the No Action alternative. 3.8.3 Development Alternatives Under development alternatives, soil disturbance would occur in construction areas, primarily along the pen~ck route. Construction techniques would be employed to minimize erosion and dust lJOblems. Topsoil would be stockpiled and lands restored and reseeded. ~ t "f if: ~ ,. -~" . '*, 3.9 Vegetation 3.9.1 Existing Conditions Species present in the study area are distributed generally within four recognizable vegetation types or associations: sagebrush-saltbush shrub and half-shrub communities along the proposed penstock alignment; agricultural lands along the proposed tailrace and penstock alignments; wetlands along the existing AB Lateral; and riparian lands along the Uncompahgre and Gunnison Rivers. Prior disturbance at the powerhouse site has resulted in the area being populated mainly with a variety of annual plants and greasewood. Vegetation surveys of the Black Canyon area were taken in 1990 by Auble, et. al. (1991). Most of the plants recorded in the area studied are widely distributed species typical of low elevation riparian zones in Colorado. The dominant woody species were box elder (Acer negundo), sandbar willow (Salix exigua), and saltcedar (Tamarix ramosissima). The most abundant forbs were scouring rush (Equisetum hyemale) and E. laevigatum), Louisiana sage (Artemisia ludoviciana), western goldenrod (Euthamia occidentalis), and sweet clover (Melilotus alba and M. officinalis). The principal sedges were woolly sedge (Carex lanuginosa) and common spikerush (Eleocharis palusris). The most abundant grasses were redtop (Agrostis stolonifera), satingrass (Muhlenbergia racemosa), reed canarygrass (Phalaris arundinace), Canada bluegrass (Poa compressa) and fowl bluegrass (Pua palustris) (Auble, et. al. 1991), Reduced spring flows resulting from Aspinall operations have generally allowed riparian vegetation to encroach toward the stream channel. Cottonwood riparian zones occur along the Uncompahgre River at and downstream from the proposed tailrace. They typically exist as narrow, well-defined, linear stands along ri verbanks or along abandoned watercourses and along manmade waterways separating upland grass and shrub lands from aquatic habitats. Other upland species in the riparian zone include Russian olive, salt cedar, clover, and various annual grasses. Much of the ~; -t ~i AS Lateral Hydropower Project July 2000