2013-09-26_REVISION - C1981008 (5)

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Map 2.04.3 Pre -Mine Land Use has been altered to reflect the more accurate characterization of the ICSG land. The natural vegetation occurring in the Nucla area has been described by Kuchler (1964) as the Juniper- Pinyon Woodland Type and the Great Basin Sagebrush Type, while Brown, et al. (1980) classified the natural vegetation communities as the Pinyon- Juniper Series of the Great Basin Conifer Woodland Biome and the Sagebrush Series of the Great Basin Desertscrub Biome. While these natural vegetation types are obvious in the surrounding undisturbed native rangelands, over 100 years of intensive agriculture on First Park has resulted in only scattered remnants of these native vegetation types in areas where soils are too shallow or irrigation water could not be applied. Prior to agricultural conversion sagebrush shrublands occupied the park -like areas with deeper soils and more gentle slopes while the more broken upland areas with shallow coarse textured soils were occupied by the pinyon - juniper woodlands. Since deeper soils are common in the study area, the sagebrush shrubland was probably the predominant vegetation in the native landscape. Western settlers desiring to convert native rangeland to agricultural ground, selected areas dominated by sagebrush because these areas contained the deeper more desirable soils and more gentle slopes. The incorporation of the Colorado Cooperative Company in 1894, completion of the Colorado Cooperative Ditch in the early 1900's, and establishment of the Nucla community during the same period were the driving forces resulting in the change from the semiarid natural vegetation types to lands dedicated to irrigated agricultural production. The present landscape and land use on First Park, and Second Park to the north across Tuttle Draw, reflects years of development and management for irrigated hay, pasture and crop production. The irrigation system reflects the typical mountain -type flood irrigation systems using gravity flow ditches, laterals, and cut -outs to insure coverage over the irregular topography. Though- theThe system is inefFieienteffective in terms of irrigation water transport and application, and is dependent on -large inputs of manpower, adequate water supplies, intensive— efforts by managers, and reuse of tail water by downfield operators hasto insure} adequate production on the s. Levels of production vary greatly with the amount and degree of management inputs.- Deeper soils on landforms that are less steep and more uniform enhance irrigation water management with consequent benefits to production. August 2013 (PR 08) 2.04.10 -8