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. O{}n~~ . . , Main Results of Mitigation Meeting of November 24, 1980, Closed Basin Division, San Luis Valley, Colorado At the subject meeting, analyses of data collected in 1979 were reviewed and analyses of data collected in 1980 were presented by Water and Power Resources Service (Water and Power) personnel. These analyses are primarily associated with predicting the effects of the project division on wetlands (water table drawdown effects). Ongoing Water and Power studies to monitor vegetation and the discharge pond near long term test well site TW3-1 were also discussed. Data were presented indicating that the TW3-1 discharge pond (wetland class P SS/EM Y) experienced no increase in the rate of seepage losses as a result of lowering the water table under the pond by about 1-1/2 feet. Water and Power map investigations showed that a total of 11,929 acres of wetlands of 14 classes would overlie areas Where a shallow water table (2-1/2 feet deep or less, 1979 data) would be lowered after about 50 years of continuous well pumping (full project division development). Tabulated results of these map investigations were distributed at the meeting and are also enclosed. Although a method for determining the degree of effects to these wetland acres has not been achieved, Water and Power personnel suggested that if the water table could be demonstrated to support ponded water or moist soils in wetlands, the degree of effects should generally increase with increasing water table drawdown. The degree of project division effects should also generally be greater for ephemeral wetlands than that for permanent wetlands. Fish and Wildlife Service (FWS) personnel suggested that a ratio based on infiitration tests across wetlands could be applied for determining the degree of effects to the wetlands. After discussion, the meeting consensus was that the FWS would pursue such a degree analysis for wetlands effects per individual wetland classes. The FWS personnel presented the results of map investigations showing that a total of 9,241 acres of wetlands would be affected by lowering the water table. Investigation criteria were similar to those used by Water and Power, except that effects to wetlands along the conveyance channel were not included in the FWS 9,241-acre total. The FWS map investigations indicated that 5,634 wetland acres along the conveyance channel could be affected because of inter- ference by the east channel embankment to sheet surface water flows across the valley floor. Water and Power personnel had not performed analyses of these conveyance channel effects. Information needs to be considered Which relates to the frequency and direction of surface water flows, the areas that could receive surface water flows, and the locations along the conveyance channel that are planned for cross drainage structures. If ground water connection to wetlands is demonstrated, the potential amount of wetlands that could experience Some degree of project division effects appeared to be in the range of 9,000 to 12,000 acres. Additional analyses by the FWS are expected to narrow this range. An analysis of the degree of ground water con- nection or the degree of effects to the wetlands may reduce these acreage estimates. The following FWS analyses also remain to be accomplished: 1. Determine the values of affected wetlands to wildlife. In wetlands evalua- tion procedures, the FWS personnel anticipate using data from Alamosa and Monte Vista National Wildlife Refuges (NwR), the Colorado Division of Wildlife, and from Blanca Wildlife Habitat Area (WHA).