December 6, 2016 Phase 2 Project Kickoff Meeting Overview Phase 1: - - PowerPoint PPT Presentation

30-Percent Engineering Design Services for the

New Mexico Unit of Central Arizona Project

December 6, 2016 Phase 2 – Project Kickoff Meeting

Overview – Phase 1: Scope and Findings Summary – Phase 2: Scope, Schedule, and Deliverables – Gila Diversion Preliminary Findings

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Phase 1: Scope and Findings

Phase 1 – Scope Summary Scope Develop Screening Criteria for Diversion and Storage Concepts along the Gila and Mogollon – Storage: reservoirs and ASR – Diversions: open channel, pipelines, and pumping – Assess environmental impacts

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Phase 1 – Selected Alternative

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Phase 1 – Selected Alternative Alternative 4 (Selected Alternative) Initial Phase – Diversion of 150 cfs – Flood infiltration and storage with additional basins in the Cliff-Gila Valley – Ranney Wells – Construct Winn Reservoir and Diversion to 3,845 AF – Pipeline and pumping to the Upper Gila ditch

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Phase 2 – Scope, Schedule, and Deliverables

Phase 2 – Scope, Schedule, and Deliverables Scope – Diversion – ASR ground water model – ASR geotechnical investigation – ASR down valley sites – Agency requirements – Additional work

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Phase 2 – Schedule

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Project Milestones – Task 6 – Project Management NTP – 11/7/2016 – Task 7 – Diversions NTP – 11/7/2016

– Draft Report Submitted 12/2/2016

– Task 8 – Coordination Meeting NTP - TBD – Task 9 – ASR Ground Water Model NTP – TBD – Task 10 – Geotechnical Investigation NTP - TBD – Task 11 – ASR Down Valley Sites NTP – TBD – Task 12 – Agency Coordination NTP - TBD

Phase 2 – Deliverables Deliverables – Diversion Report – ASR Numerical Model – ASR Geotechnical Report – Down Valley ASR Observations Memorandum – Permitting Summary Memorandum

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Gila Diversion Preliminary Findings

Gila Gage Diversion Site – Gila Stream Gage

• USGS 09430500

– Land Ownership

• US Forest Service (USFS)
• No diversion activities on USFS lands
• TNC & State of New Mexico
• Co-ownership
• National Lands Protection Act (NLPA)

– Access Road Improvements

• Regrade slopes >12%
• Crossing of Mogollon Creek
• Construction & maintenance

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Conceptual Diversion Alternatives Criteria

Site Evaluation Criteria – Available Head

• Highest point below USFS boundary

– All Weather Access

• Except during flooding events

– Structural Stability

• Key diversion to bedrock

– Lateral & Vertical Channel Stability

• Bedrock along both banks
• Observed channel degradation

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Design Alternatives Selection Criteria – Structure Design

• Grouted boulder vs. cast concrete
• Adjustable vs. fixed invert
• At grade vs. surface water intake

– Sediment Transport

• Promote sediment continuity
• Prevent erosion & sedimentation

– Structure Bypass

• Maintain design channel alignment
• Prevent future channel avulsion

– Upstream Fish Passage

• Design to T&E species requirements
• Minimize limiting velocities & depths

– Downstream Navigability

• Minimize recreational hazards

http://www.wildlife.state.nm.us/fishing/game-fish/cold-water/ 30 Percent Engineering Design Services for New Mexico Unit of Central Arizona Project 15

Conceptual Diversion Alternatives 30% Design

Engineered Riffle Diversion

– Invert 4662’ to 4666’ – Grouted Boulder or Concrete – Cast Concrete Walls – Elongated Riffle Rundown – Riprap Bank Protection – Bedload Deflection – Fish & Debris Exclusion – Sediment Sluicing – Surface Conveyance Canal

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Engineered Riffle Diversion – Pros

• Cost to construct
• Fewer mechanical systems
• Reduced power requirements
• Recreational navigation

– Cons

• Non-adjustable invert
• Static sediment management
• No fish passage channel
• Reduced flood flow conveyance

Engineered Riffle: Kremlin, CO 30 Percent Engineering Design Services for New Mexico Unit of Central Arizona Project 18

Obermeyer Pneumatic Gates Diversion

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– Gates Raised 4662’ to 4666’ – Cast Concrete Sill & Walls – Riprap Bank Protection – Mechanical Infrastructure

• Steel gates, pneumatic lines,

bladders, compressors,

• perations controls & housing

– Bedload Deflection – Fish & Debris Exclusion – Sediment Sluicing – Surface Conveyance Canal

Obermeyer Pneumatic Gates Diversion – Pros

• Adjustable invert
• Dynamic sediment flushing
• Fish passage opportunities
• Flood flow conveyance

– Cons

• Cost to construct
• Mechanical systems maintenance
• Additional power requirements

Albuquerque Diversion Dam: http://mapio.net/pic/p-5170793/ 30 Percent Engineering Design Services for New Mexico Unit of Central Arizona Project 20

Combination Coanda Screen & Obermeyer Pneumatic Gate Diversion

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– Gates Raised 4662’ to 4666’ – Cast Concrete Sill & Walls – Riprap Bank Protection – Coanda Screens

• 1 mm opening

– Water Collection Vaults – Mechanical Infrastructure

• Steel gates, pneumatic lines,

bladders, compressors,

• perations controls & housing

– Sediment Sluicing – Subgrade Conveyance Culvert

Combination Coanda Screen & Obermeyer Pneumatic Gate Diversion – Pros

• Partially adjustable invert
• Limited sediment flushing
• Sediment & debris exclusion
• Fish passage opportunities

– Cons

• Cost to construct
• Mechanical systems maintenance
• Sedimentation in vaults
• Reduced head for conveyance
• Additional power requirements

http://www.elginindustries.com/equipment_group/norris_screen/products/product_line/Norri s_Screen/stainless_steel_screening_systems/coanda_screen 30 Percent Engineering Design Services for New Mexico Unit of Central Arizona Project 22

Channel Response to Historic Changes in the River System

River Channel Modifications in the Cliff-Gila Valley – Channelization

• Straightening & leveeing
• Steeper channel slopes

– Disconnection of Floodplain

• Reduced overbank flood storage
• Loss of vegetation & bank stability

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Dynamic Channel Response in Cliff-Gila Valley – Independent of Flood Severity – Vertical Channel Instabilities

• Upstream degradation
• Headcutting
• Downstream aggradation
• Braiding

– Lateral Channel Instability

• Bank erosion & failure
• Channel avulsion

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Observed Channel Response at Gila Gage Site – Ongoing Channel Incision

• Propagation of headcuts

initiated downstream

– Channel Abandonment

• Historically irrigated fields
• Fluvial landforms
• USGS stream gage facility

– Lowered Shallow Water Table

• Perched riparian vegetation
• Expanded upland conditions

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Ecological & Functional Restoration of the Gila River

Intent of Reach-Scale Channel Restoration – Re-elevate Incised Channel – Restore Stable Channel Geometries – Reduce Over-steepened Banks – Reconnect Abandoned Floodplains – Raise Shallow Water Tables – Reestablish Native Riparian Zones

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Pros & Cons of Restoration to Diversion Project – Improve River Function

• Vertical & lateral channel stability
• Sediment continuity of reach

– Raise Diversion Elevations

• Gravity feed ASR infiltration fields

– Restore Aquatic & Riparian Habitats

• T&E species

– Benefit River Based Recreation

• Existing hazards

– Disadvantages of Restoration

• Increased project cost
• Temporary construction impacts

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Next Steps

Recommended Path Forward – Continued Fluvial Geomorphic Analysis – Additional Hydraulic Modeling – Initiate Sediment Transport Modeling – Field Investigations for ASR – Stream Restoration Evaluation

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Questions?

December 6, 2016