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<br />I <br /> <br />I <br /> <br />infiltration rate and, thereby ,a shortened time period during the summer when <br />surface water was present. Evaporation is the primary cause of water loss from <br />wetland areas. <br /> <br />Drawdown pumping may increase wind erosion of soils. This effect would most <br />likely occur in specific areas where the existing shallow aquifer is close to <br />the ground surface. Plant vigor and density will be reduced because of drawdown <br />pumping. Existing livestock grazing capabilities and production could also be <br />aff ec ted . <br /> <br />II <br /> <br />Construction of the 42-mile conveyance channel could affect natural existing <br />overland flow of surface waters. Since annual precipitation within project <br />boundaries amounts to only 6 to 8 tnches, most of the annual surface water <br />runoff is derived from snowmelt from adjacent mountain ranges. Almost all of <br />the surface runoff water is located in the northern part of the project area <br />in Stages 3, 4, and 5. Only minimal surface flows are received in the southern <br />part, or Stage 1-2 of the project. Channel construction will not affect any <br />natural overland flows in Stage 1-2. ' <br /> <br />i <br />I, <br />'I <br />I <br /> <br />In Stages 3, 4, and 5, conveyance channel construction will affect the natural <br />overland flow of surface runoff waters through about 4,920 acres of existing <br />wetlands and wetland habitat. At identifiable drainage points of the conveyance <br />channel, structures will pass runoff waters under or over the channel. The <br />locations of the structures have not been specifically determined at this time <br />but will be positioned to minimize interruptions of overland flows. <br /> <br />Construction of roads (about 10 feet wide) for access to pump well sites along <br />the lateral delivery system will directly displace about 80 acres of wetlands or <br />wetland habitats. When possible, pump wells will be located outside wetland <br />depressions and will, therefore, have minimum effect on wetlands or wetland <br />habitat because of construction. <br /> <br />A total of 4,946 acres of wetlands will be affected by construction of the <br />42-mile conveyance channel (26 acres on the Blanca WHA) and 80 acres by con- <br />struction of roads associated with the pump well field system. The total <br />amount of wetlands and wetland habitats affected by construction activities <br />within project boundaries will, therefore, be 5,026 acres. <br /> <br />The total amount of wetlands adversely affected by drawdown pumping within <br />project boundaries is 3,434 acres, of which 173 acres are on the Blanca WHA. <br />The total amount of wetlands adversely affected by project construction and <br />drawdown pumping is 8,460 acres. <br /> <br />3. Mitigation. A total of 8,460 acres of various wetland types will <br />be affected by construction of the conveyance channel and roads (5,026 acres) <br />and water table drawdown because of project pumping (3,434 acres). <br /> <br />Replacement of the 8,460 acres of wetlands damaged by construction and opera- <br />tion of the project can be accomplished through the maintenance, improvement, <br />or development of existing or new wetland areas on Alamosa NWR, Blanca WHA, <br /> <br />g <br /> <br />,-. ~ .c~ r"\ - ...... <br />"" .L l. ':J v <br /> <br />I <br />