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The Central Nebraska Public Power and Irrigation District Groundwater Mound Study

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Purpose Main Objectives Evaluate the groundwater mound in the vicinity of lands irrigated by CNPPID facilities Provide an understanding of the temporal and spatial changes of the groundwater mound Identify factors affecting the groundwater mound

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Key Terms CSD Groundwater Level Monitoring Reports UNL-Conservation and Survey Division `

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Key Terms CSD Wells Database of water levels from wells used in CSD report

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Key Terms Study Area

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Groundwater Mound Study Recap Estimated Mound Volume CSD well method Water balance method Subareas Spatial and Temporal Movement Adjustment Impact Diversions ET

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Groundwater Mound Size and Shape Annual Groundwater Mound Volume

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Groundwater Evaluation Water Balance

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CSD Mound Volume Compared to Water Balance Mound Volume Mound Volume Calculated using the Water Balance Mound Volume Calculated using CSD Well Data

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Water Balance Adjusted Diversions Annual Groundwater Mound Volume No Diversions 50% Diversions 75% Diversions CSD Well Data 125% Diversions 100% Diversions 25% Diversions

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Water Balance Adjusted ET Annual Groundwater Mound Volume 95% ET 98% ET 105% ET 102% ET CSD Well Data Un-Adjusted ET

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Primary Conclusions Groundwater Mound Size and Volume Increasing trend from the 1950s to 2000. No longer an increasing trend since 2000.

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The Future of the Mound Declining Surface Water Recharge Reduced Water Supply in Lake McConaughy (Allocations) Increased efficiencies (Conservation) 1950-2000 average recharge = 145,000 af Since 2000 average recharge = 90,000 af Declining Mound Negative Water Balance

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Questions?