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Methow Valley Irrigation District: Alternatives Evaluation Report

Detailed assessment of 4 irrigation system alternatives, including groundwater investigation results and implementation costs.

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Methow Valley Irrigation District: Alternatives Evaluation Report

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  1. Methow Valley Irrigation District Alternatives Evaluation Presented by Bob Montgomery, P.E. and David Rice, P.E. January 31, 2013

  2. Alternatives Evaluation Report (AER) Scope • Coordination meetings • Meetings with project team • MVID board of directors and shareholders • Hydrologic feasibility analysis • Groundwater well testing • Evaluation of individual well option • Development of AER • Evaluation of 4 alternatives • Hydraulic analyses, cost analyses, concept drawings • Draft and final reports

  3. Groundwater Investigation • Potential well sites identified • Test well drilling plan developed • Description and specifications for drilling work • Test well drilling – 8 inch exploration wells • MVID beaver pond property • Jumars property • Eileen property

  4. Summary of Drilling at MVID Beaver Pond Property • Well drilled to 90 ft below ground surface (bgs) • Static water level was 10 ftbgs • Encountered bedrock at 80 ftbgs • We are not recommending this site be used for production wells

  5. Summary of Drilling at Jumars Property • Well drilled to 180 ftbgs • Static water level was 69 ftbgs • Good formations of sand and gravel were found • Pump test not performed because of freezing weather

  6. Summary of Drilling at Eileen Property • Well drilled to 156 ftbgs • Static water level was 8 ftbgs • Good formations of sand and gravel were found • Higher withdrawals likely available at this site • Pump test not yet performed

  7. Summary of Alternatives • Alternative 1 • West canal replaced with pressurized pipe system • Supplied by pump station on Methow River • Alternative 2 • West canal replaced with pressurized pipe system • Supplied by wells in connection with Methow River • Alternative 3 • West canal replaced with two pressurized pipe systems • Supplied by wells in connection with Methow River

  8. Summary of Alternatives (Cont.) • Alternative 4 • Convert to individual well systems, where possible • Reduced West system – Upper West Side users • Pressure pipe system • Supplied by well (or river pump station) • Users likely still within a reduced MVID • Reduced East system – Lateral E1 replacement • Pressure pipe system • Supplied by well • System operated as part of a reduced MVID, or through agreement with Town of Twisp

  9. Alternative 1

  10. Alternative 1 – Detailed Summary • Supply • Methow River pump station • 2.4 cfs (125 HP) pumping to users upstream • 8.6 cfs (200 HP) pumping to users downstream • Pressurized PVC pipe system • Main line – approx. 47,800 feet, 8” to 18” diam. • Laterals – approx. 29,600 feet, 3” to 8” diam. • Storage (optional) • 132,000 gallons (upstream of pump station) • 476,000 gallons (downstream of pump station)

  11. Alternative 1 – Implementation Costs • Probable construction cost • $6 to $7 million (2013 dollars) • Additional implementation costs • Land acquisition, engineering, permitting, administrative

  12. Alternative 1 – Life Cycle Costs • Probable annual life cycle costs • Power: $30K to $35K (2013 dollars) • O&M: $140K to $160K (2013 dollars) • Replacement fund: $55K to $65K (2013 dollars) • Probable annual assessment • $155 to $165 per acre for power + O&M • $50 to $60 per acre for replacement fund • Analysis assumes • Okanogan PUD irrigation rate schedule • 3% annual inflation and 3% annual interest

  13. Alternative 2

  14. Alternative 2 – Detailed Summary • Groundwater well supply • Total 11.0 cfs supply • Multiple large production wells • Booster pump station • 2.4 cfs (75 HP) pump station to users upstream of Roach Spill

  15. Alternative 2 – Detailed Summary (Cont.) • Pressurized PVC pipe system • Main line – approx. 47,800 feet, 8” to 18” diam. • Laterals – approx. 29,700 feet, 3” to 8” diam. • Storage (optional) • 132,000 gallons (upstream of pump station) • 476,000 gallons (downstream of pump station)

  16. Alternative 2 – Implementation Costs • Probable construction cost • $6.5 to $7.5 million (2013 dollars) • Additional implementation costs • Land acquisition, permitting, administrative

  17. Alternative 2 – Life Cycle Costs • Probable annual life cycle costs • Power: $40K to $45K (2013 dollars) • O&M: $145K to $165K (2013 dollars) • Replacement fund: $60K to $70K (2013 dollars) • Probable annual assessment • $160 to $170 per acre for power + O&M • $50 to $60 per acre for replacement fund • Analysis assumes • Okanogan PUD irrigation rate schedule • 3% annual inflation and 3% annual interest

  18. Alternative 3

  19. Alternative 3 – Detailed Summary • Groundwater well supply • Upper middle system - total 5.1 cfs supply • Lower system - total 5.9 cfs supply • Multiple large production wells • Booster pump station • 2.4 cfs (75 HP) pump station in upper/middle system to users upstream of Roach spill

  20. Alternative 3 – Detailed Summary (Cont.) • Pressurized PVC pipe system • Main line – approx. 41,100 feet, 8” to 15” diam. • Laterals – approx. 29,700 feet, 3” to 8” diam. • Storage (optional) • Upper/middle system • 132,000 gallons (upstream of pump station) • 158,000 gallons (downstream of pump station) • Lower system • 317,000 gallons

  21. Alternative 3 – Implementation Costs • Probable construction cost • $5.5 to $6.5 million (2013 dollars) • Additional implementation costs • Land acquisition, permitting, administrative

  22. Alternative 3 – Life Cycle Costs • Probable life cycle costs • Power: $40K to $45K (2013 dollars) • O&M: $145K to $165K (2013 dollars) • Replacement fund: $60K to $70K (2013 dollars) • Probable assessment • $165 to $175 per acre for power + O&M • $50 to $60 per acre for replacement fund • Analysis assumes • Okanogan PUD irrigation rate schedule • 3% annual inflation and 3% annual interest

  23. Alternative 4

  24. Alternative 4 – Detailed Summary • Combination of individual well systems and pressurized pipe system where wells are not feasible • Individual well systems • For parcels outside town of twisp • Groundwater likely available in valley and margins in unconsolidated sediment formation • Recommend drilling deeper and using screens for higher capacity wells

  25. Alternative 4 – Detailed Summary • Reduced Upper West system • Groundwater well supply – 2.5 cfs • Pressurized PVC pipe system • Approx. 21,100 feet, 3” to 12” diam. • Storage (optional) • 132,000 gallons

  26. Alternative 4 – Detailed Summary (Cont.) • Reduced Upper East System • Groundwater well supply – 2.5 cfs • Pressurized PVC pipe system • Approx. 6,100 feet, 4” to 10” diam. • No storage • Operation • Part of reduced MVID, or • Served through agreement with Town of Twisp with separate irrigation meter

  27. Alternative 4 – Implementation Costs • Probable construction cost for reduced MVID system (Upper West and Upper East systems) • $2.1 to $2.6 million total (2013 dollars) • $1.5 to $1.8 million for upper west (2013 dollars) • $600K to $800K for upper east (2013 dollars) • Additional implementation costs • Land acquisition, permitting, administrative

  28. Alternative 4 – Life Cycle Costs • Probable life cycle costs for reduced MVID (upper west and upper east systems) • Power: $12K to $16K (2013 dollars) • O&M: $20K to $30K (2013 dollars) • Replacement fund: $27K to $32K (2013 dollars) • Probable assessment • $180 to $190 per acre for power + O&M • $120 to $130 per acre for replacement fund • Analysis assumes • Okanogan PUD irrigation rate schedule • 3% annual inflation and 3% annual interest

  29. Comparison of Alternatives

  30. Next Steps • Completion of AER • MVID selection of preferred alternative • Selection criteria • Cost (construction cost, land acquisition, O&M, replacement, impact to shareholder assessment) • Water supply (impact to groundwater, surface water, and continuity with methow river) • Property impacts • Social and political feasibility • Ease of permitting • Constructability, ease of operation

  31. Questions and Comments • To be collected at tables for each alternative • For more information: • See www.mvid.org • Talk with MVID Directors and Staff • Visit the Trout Unlimited office in Twisp • (115 S. Glover St.) • Email questions and comments to: mvid@methownet.com

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