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perennial weedy species. Map 2.04.3 Pre -Mine Land Use has been altered to reflect the more <br />accurate characterization of the ICSG land. <br />The natural vegetation occurring in the Nucla area has been described by Kuchler (1964) as <br />the Juniper- Pinyon Woodland Type and the Great Basin Sagebrush Type, while Brown, et al. <br />(1980) classified the natural vegetation communities as the Pinyon- Juniper Series of the Great <br />Basin Conifer Woodland Biome and the Sagebrush Series of the Great Basin Desertscrub <br />Biome. While these natural vegetation types are obvious in the surrounding undisturbed <br />native rangelands, over 100 years of intensive agriculture on First Park has resulted in only <br />scattered remnants of these native vegetation types in areas where soils are too shallow or <br />irrigation water could not be applied. Prior to agricultural conversion sagebrush shrublands <br />occupied the park -like areas with deeper soils and more gentle slopes while the more broken <br />upland areas with shallow coarse textured soils were occupied by the pinyon - juniper <br />woodlands. Since deeper soils are common in the study area, the sagebrush shrubland was <br />probably the predominant vegetation in the native landscape. Western settlers desiring to <br />convert native rangeland to agricultural ground, selected areas dominated by sagebrush <br />because these areas contained the deeper more desirable soils and more gentle slopes. <br />The incorporation of the Colorado Cooperative Company in 1894, completion of the Colorado <br />Cooperative Ditch in the early 1900's, and establishment of the Nucla community during the <br />same period were the driving forces resulting in the change from the semiarid natural <br />vegetation types to lands dedicated to irrigated agricultural production. The present landscape <br />and land use on First Park, and Second Park to the north across Tuttle Draw, reflects years of <br />development and management for irrigated hay, pasture and crop production. The irrigation <br />system reflects the typical mountain -type flood irrigation systems using gravity flow ditches, <br />laterals, and cut -outs to insure coverage over the irregular topography. Though the system is <br />inefficient in terms of irrigation water application and is dependent on large inputs of <br />manpower, adequate water supplies, intensive efforts by managers and reuse of water by <br />downfield operators has insured adequate production on the lands. Levels of production vary <br />greatly with the amount and degree of management inputs. Deeper soils on landforms that <br />are less steep and more uniform enhance irrigation water management with consequent <br />benefits to production. <br />Revised September 2010 (PR 06) 2.04.10 -8 <br />