fish screen replacement project presentation to …

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