fish screen replacement project presentation to …
TRANSCRIPT
FISH SCREEN REPLACEMENT PROJECT
PRESENTATION TO ANGLER FRATERNITY
TEMUKA DECEMBER 14TH 2020
PRESENTATION OVERVIEW
• Existing RDR and New Facility
• Background to Project
• Key Objectives
• Design Specifics
• Status and Programme
RDR and NEW FISH SCREEN LOCATION
RDR Intake
see next slide for detail here
RDR and NEW FISH SCREEN
NEW FISH SCREEN – LAYOUT
new canal
existing RDR
new bypass
FISH SCREEN – LAYOUT
EARLY MODEL
FISH SCREEN – T-SCREENS
FISH SCREEN – T-SCREEN
FACILITY OVERVIEW
COMPUTER MODEL“Fish eye” view
looking downstream
FACILITY OVERVIEW
COMPUTER MODEL
One Tee Screen in maintenance
position
FACILITY OVERVIEW
COMPUTER MODEL
Flat screen section (bottom right)
FISH SCREEN – LAYOUTTHIS ONE”S
REAL!(Waitaki Dam)
BACKGROUND TO PROJECT• Innovative fish barrier installed ~2007
• Bio-Acoustic Fish Fence (BAFF) proved ineffective in excluding fish from Race (4% - 97%; avg 30%)
• Numerous attempts to modify the installation to improve performance but with marginal success
• Jan 2016 – non-compliance notice from ECan
• Feb 2016 - Commitment by RDRML to replace BAFF
BACKGROUND TO PROJECT• Sept 2016 – resource consents lodged for replacement with
Rock Bund Infiltration Gallery (RBIG)
• Submissions opposed the RBIG and an alternative design was investigated; April 2017 USA Study Tour
• Jan 2018 – new consent application for a rotary mechanical screen
• June 2018 – consents granted for rotary mechanical screen
• July 2018 – various consents appealed
• July 2019 – appeals on all fish screen consents resolved
BACKGROUND TO PROJECT• Oct 2019 – construction contract tendered based on a
design and build basis (concept design tendered)
• January 2020 – no complying tenders received (design risk; contracting environment)
• RDRML Board agrees to alternative contracts – fully designed scheme to be tendered; separate screen supply; construct only contract
• Focus on full design of facility
BACKGROUND TO PROJECT• Computer Fluid Dynamics (CFD) modelling results
identify velocity sensitivities – design revised
• Wider channel – limit on sweep velocities
• Flat screens required
• Baffles to moderate and balance flows through screens
• Enhancements to screen design by AWMA
• Further CFD modelling for confidence
FISH SCREEN – CFD MODELLING
FISH SCREEN – CFD MODELLING
BACKGROUND TO PROJECT• COVID 19 - internet overload!
• July 2020 – fish screen supply contract with AWMA
• Sept 2020 – construction contract tendered
• Oct 2020 – Environment Court suggests consents haven’t commenced
• Nov 2020 – tenders closed
• Dec 2nd Designer advises some flow velocities exceed design
• Dec 9th Env Court Hearing re consents
KEY OBJECTIVES• Resource Consent CRC182542 – conditions require:
• Exclude fish and return safely to the river
• Design to NIWA Guidelines or Schedule 2 LWRP
• Low Screen Approach Velocity (average <0.12 m/s)
• High Sweep Velocity (at least twice Approach Velocity)
• Testing Regime – initial and on-going to measure key velocities and to sample fish after the screen (in by-pass)
• Complete construction within 30 months (Jan 2021?)
KEY OBJECTIVES• RDRML Objectives
• Build the right facility
• Meet or exceed consent conditions
• Flow capacity (~34 cumecs plus 10 cumecs)
• Manage sediment (maintain flow velocity through system)
• Budget control
It has to WORK!
DESIGN SPECIFICS• Approach velocity < 0.12 m/s
• Enough screen area (374m2)• Need for flat screens
• Balance the flows (regulate through each screen)
• Sweep velocity• Seeking high sweep for fish and sediment (> 0.6 m/s)
• High sweep velocity (>1.0 m/s) impacts on screen effectiveness
• 0.9 m/s target
DESIGN SPECIFICS• Fish Bypass effectiveness
• Safe fish passage back to river
• Testing facility to assess fish condition after the screen
• Use experience from BAFF where fish are caught in the by-pass channel
FISH BYPASS
FISH BYPASS CHANNEL – BAFF Photo shows fish by-pass channel in the existing BAFF fish screen. Structure is for sampling fish in the by-pass.
FISH BYPASStransition from fish screen into by-pass
FISH BYPASS – FLOW TRANSITION
DISCHARGE via LAY FLAT GATE intoOPEN FISH BAYPASS CHANNEL
View looking upstream
FISH TRAP in BAFF BYPASS CHANNEL
NEW FISH CAPTURE WEIR “PIANO KEY DESIGN”
NEW FISH CAPTURE WEIR “PIANO KEY DESIGN”
View looking upstream(no fish capture traps shown)
NEW FISH CAPTURE WEIR “PIANO KEY DESIGN”SCALE MODEL
NEW FISH BYPASS CHANNEL – PROFILE AND VELOCITY
Black lines shows profile (vertical scale exaggerated)
Blue line indicates velocity along bypass channel
Location of testing weir
STATUS AND PROGRAMME• Preferred contractor identified
• First screen shipped from AWMA
• Environment Court confirmed consents (awaiting written notice)
• Design changes required to moderate flows
• Original construction programme now very high risk
• Cutover and commissioning most likely May 2022
DESIGN CHANGE DETAILS• Sweep velocities peaking at 1.3 m/s
• Tee screens become inefficient
• We are not convinced that there is sufficient understanding of why these flows are now evident
• Require confidence in proposed changes before committing to construction
PROGRAMME - 2021• Pre-construction works (concrete elements)
• Supply of all fish screen elements
• Development of fish capture and testing methods
• Validation of design
• Construction start ~ August 2021
FISH SCREEN – UNDER CONSTRUCTIONMAIN BODY FABRICATION
FISH SCREEN – UNDER CONSTRUCTIONONE SCREEN CYLINDER
FISH SCREEN – TESTING
FISH SCREEN #1 – ON ITS WAY!
RANGITATA DIVERSION RACE MANAGEMENT LTD
Thank you