March 2017 Palouse Basin Aquifer Committee Palouse Groundwater Basin Water Supply Alternatives Analysis Report Prepared for Palouse Basin Aquifer Committee/University of Idaho March 2017 Palouse Basin Aquifer Committee Palouse Groundwater Basin Water Supply Alternatives Analysis Report Prepared for Prepared by Palouse Basin Aquifer Committee/University Anchor QEA, LLC of Idaho 8033 West Grandridge Blvd., Suite A Kennewick, Washington 99336 and HDR Engineering Inc. 2805 St Andrews Loop Pasco, Washington 99301 with EA Engineering, Science, and Technology, Inc., PBC 8019 W. Quinault Ave., Suite 201 Kennewick, Washington 99336 TABLE OF CONTENTS Executive Summary ..................................................................................................................... ES-1 1 Introduction ................................................................................................................................ 1 1.1 Study Purpose and Palouse Groundwater Basin Overview ................................................................. 1 1.2 Prior Studies and Related Planning Documentation ............................................................................. 3 1.3 Study Process Overview .................................................................................................................................... 3 2 Water Demands and Regional Supplemental Supply Target ......................................... 5 2.1 Historical and Recent Water Use in the Palouse Basin ......................................................................... 6 2.2 Population and Projected Growth in the Palouse Basin ...................................................................... 7 2.3 Demands with Additional Water Conservation ....................................................................................... 8 2.4 Summary Results ................................................................................................................................................. 8 3 Projects Evaluated .................................................................................................................. 12 3.1 Project and Management Action Summaries ....................................................................................... 12 3.2 Project Screening ............................................................................................................................................. 21 3.2.1 Step 1: High-level Screening ........................................................................................................ 21 3.2.2 Step 2: Detailed Screening ............................................................................................................ 22 4 Formulate and Analyze Alternatives .................................................................................. 28 4.1 Alternative Descriptions ................................................................................................................................. 28 4.1.1 Alternative 1 ....................................................................................................................................... 28 4.1.2 Alternative 2 ....................................................................................................................................... 29 4.1.3 Alternative 3 ....................................................................................................................................... 29 4.1.4 Alternative 4 ....................................................................................................................................... 29 4.2 Evaluation Criteria ............................................................................................................................................ 31 4.2.1 Criteria Assessed Monetarily ........................................................................................................ 31 4.2.2 Criteria Assessed Quantitatively ................................................................................................. 33 4.2.3 Criteria Assessed Qualitatively .................................................................................................... 33 4.3 Evaluation Methods ......................................................................................................................................... 35 4.3.1 Lifecycle Cost Analysis Assumptions ......................................................................................... 35 4.3.2 Modeling Uncertainty and Risk ................................................................................................... 36 4.3.3 Cost and Schedule Uncertainty ................................................................................................... 37 4.3.4 Yield Uncertainty ............................................................................................................................... 42 4.4 Results .................................................................................................................................................................. 43 Palouse Basin Groundwater Supply Alternatives Analysis i March 2017 5 Findings and Recommendations ........................................................................................ 47 6 Data Gaps, Information Needs, and Next Steps, ............................................................ 49 6.1 Alternative 1 ....................................................................................................................................................... 50 6.2 Alternative 2 ....................................................................................................................................................... 50 6.3 Alternative 3 ....................................................................................................................................................... 51 6.4 Alternative 4 ....................................................................................................................................................... 52 6.5 First Priority Actions for Alternatives ........................................................................................................ 53 7 References ................................................................................................................................ 55 TABLES Table 1 Summary Projected Palouse Groundwater Basin Water Demands ...................................... 9 Table 2 Water Supply Projects Summary ....................................................................................................... 14 Table 3 Step 1 High-level Screening Results ................................................................................................ 21 Table 4 Annual Yield Categories ........................................................................................................................ 23 Table 5 Palouse Basin Aquifer Committee (PBAC): Water Supply Alternatives – Preliminary Screening Results ............................................................................................................. 24 Table 6 Alternative Evaluation Criteria ............................................................................................................ 31 Table 7 Assessment of Qualitative Criteria and Impacts to Cost/Schedule .................................... 40 Table 8 Uncertainties in Cost Contingencies ................................................................................................ 40 Table 9 Uncertainties in Schedule ..................................................................................................................... 42 Table 10 Uncertainties in Yield .............................................................................................................................. 43 Table 11 Summary of Key Findings ..................................................................................................................... 48 Table 12 First Priority Actions ................................................................................................................................ 53 FIGURES Figure 1 Palouse Groundwater Basin .................................................................................................................... 2 Figure 2 Historical and Current Groundwater Levels ..................................................................................... 3 Figure 3 Water Levels – Grande Ronde Short-term ....................................................................................... 6 Figure 4 Palouse Basin Historic Groundwater Pumping, 1992 to 2016 ................................................ 7 Figure 5 Overall Palouse Basin – Historic Supply and Demand Forecast Data ............................... 11 Figure 6 Calculation for Social Cost of Increased GHG and CACs ........................................................ 36 Figure 7 Diagram of Monte Carlo Simulation Process ............................................................................... 37 Figure 8 Example Probability Distribution Curves........................................................................................ 39 Palouse Basin Groundwater Supply Alternatives Analysis ii March 2017 Figure 9 Cost-effectiveness Comparison of Alternatives .......................................................................... 44 Figure 10 Water Delivery Reliability Comparison