Hikurangi Swamp Working Group Meeting 2/5/14 Topic/Owner Information - - PowerPoint PPT Presentation

Hikurangi Swamp Working Group Meeting 2/5/14

Topic/Owner Information 1 Last Meeting and apologies Minutes 2 Terms of Reference & Code of Conduct 3 Operations/Maintenance June 2014 Storm

• Pump Operation
• Spillway Levels
• Junction Stopbank Cut

Te Mata Electrical Board Performance Pumps Rewind Power Usage Okarika Stations Moir Tell Tales Grazing on Bermland AMP 4 Finances HydroTech Report Review 2014/15 CAPEX (Stop bank adjustments) 5 14-15 Drain Clearing Drain Clearing Proposal 6 Environmental issues Eels Okarika Ox-Bow re-establishment 7 Long term considerations (OPUS Presentation) Hikurangi Plains Water 8 River Works Supervisors Seminar Summary of seminar 9 AOB Depreciation

Terms of reference

• Pocket reps – nominations of attendees?

Operations /Maintenance – June Storm

June Storm – Overview & Pump Operations

• Hydrotech undertook a storm readiness procedure and were
• nsite for the majority of the rainfall event and subsequent

days when pumps were operating

• Pumps were isolated when the spillways were spilling to save

power, and were re-started when river level dropped.

• 240 Pleuger pump at Okarika was temporarily unavailable

when a contactor failed 3pm 11th June, repaired by 7:30pm 12th

• Pump C at Okarika, B at Ngararatunua out. Both small Pleugers
• Pumps switched off – Fri 20th (Ngara), Sat 21st (others), Sun

22nd (Mountain)

• No evidence of fish harm at stations – though outlets largely

underwater

• Spillways operated on all pockets between 1800 on

10th June between 12:00 & 1600 on 11th June, with exception of Junction pocket which continued spilling until 06:00 on 12th June – see figures

• The storm highlighted the need for the stopbank re-

adjustments, with water spilling in a number of locations over the stopbanks as well as the spillways

June Storm – Overview & Pump Operations contd.

50 100 150 200 250 300 350 400 450 500

Spillway Sensor Data (mm) - 10 to 12 June 2014

Ngara 1 Junc 1 Moun 1 Okar 1 Oton 1 Tane 1 Te Ma 3

June Storm – Junction Stopbank Cut

• Junction pocket was cut by farmer to release the

floodwater

• Both WDC & NRC attended the location
• NRC likely to issue abatement notice and fine.
• Farmer to pay for repair, including WDC engineer.
• Jonda doing work.
• WDC to consider consent change to permit works

Te Mata Electrical Board Performance

• The Te Mata Switchboard was commissioned on 9th May
• The switchboard operated as designed, satisfactorily operating the June event,

controlling the pumps as per existing level controls

Pump Re-wind Update

• 3 small pleugers are away now being re-

wound

• The large recently re-wound pleuger, stored

at Kioreroa Road has been vandalised of its feeder cables and propeller by thieves who broke onto site. Pump has been sent away to establish repair costs. Insurance job.

Power Usage

Okarika Station Moir Tell Tales

16-5-14 18-4-14 11-6-14 10-6-14

Grazing licenses

• There have been three instances of cattle

being spotted on Council Bermland with unrestricted access to waterways, one instance a repeat offender.

• Council will be forced to seek a withdrawal of

licences if warnings are not heeded.

Activity Management Plan

• Required by law to prepare one
• 20 year plan with up to 50 year forecast
• Opus asked to prepare proposal to do in

Conal’s absence.

• To include structural and H&S assessment of

stations

HydroTech April Report Review – General Info

• Couple stormy days pre-easter weekend
• Digger utilised at Ngararatunua & Otonga to

clear weeds

• Following events, stations checked and ensure

clear of weeds

HydroTech April Report Review – Pump Hours Run

Pump Pocket

Junction Te Mata Tanekaha Mountain Otonga Ngararatunua Okarika

A 14 5 2 70 55 5 B 53 25 8 58 C D 4 1 E 5 1

All pumps were available at month end, apart from pump C at Okarika and pump B at Ngararatunua.

HydroTech April Report Review - Finances

Inspection Maintenance Environmental Flood Attendance Drain Clearing

$2,638.23 $350.34 $50.74 $654.53 $0

Maintenance – Send Pump B and Pump A’s starter away at Mountain Environmental – Lift flood gates for Eels

HydroTech May Report Review – General Info

• Weather mild with little rainfall, allowing drain

clearing to be completed for year

• Pump at Junction has been re-installed

following refurbishment

• Pre-fabricated stainless steel ladders have

been installed to allow pump access at Otonga, Ngararatunua & Okarika as part of the annual pump inspections, (existing ladders corroded and unsafe)

HydroTech May Report Review – Pump Hours Run

Pump Pocket

Junction Te Mata Tanekaha Mountain Otonga Ngararatunua Okarika

A B 5 C D E

All pumps were available at month end, apart from pump C at Okarika and pump B at Ngararatunua. Pump A at Junction was brought out and back into service during the month

HydroTech May Report Review - Finances

Inspection Maintenance Environmental Flood Attendance Drain Clearing

$2,638.22 $9,720.15 $790.8 $738.71 $14,657.34

Maintenance – Install rat bait traps in all stations, commissioning of Te Mata, gate damage and ladder replacements, lifting of pump A at Mountain and concrete spalling investigation Environmental – Okarika Ox-bow restoration Drain Clearing – April, Lupton & Wilsonville Drains and Otonga Stream Cleared, also some willow tree removals

YTD and forecast

• “Payment to ext contractors” and “plant and equipment maint” includes

budget to rewind 3 small pleugers and undertake electrical improvements.

Account Description 2013/14 Actuals YTD 2013/14 Budget Full Year 2013/14 Current Forecast Full Year 2014/15 Budget Curr Vers Refreshments Provided Freight & Cartage 2,000 Electricity Supply Costs 41,697 173,000 102,781 180,000 Management Fee Uniforms Water Rights Paid NRC Consent 5,000 2,000 2,000 Payments to External Contractors 84,034 295,000 229,143 190,000 Legal Fees (13,730) 10,000 (2,493) 10,000 Engineering Fees (10,976) 4,576 (10,771) 30,000 Other Professional Fees 2,652 5,000 5,877 5,000 Infrastructure & Services (not Contract) 72,654 5,000 Plant & Equip Maintenance non Contract 110,393 43,000 118,843 100,000 Grand Total 286,724 542,576 445,380 517,000

Stopbank Adjustments

• Budget in annual plan - $357k
• WDC to seek Clements to confirm price to

avoid retender

• Kennedy and Associates to do inspections and

manage onsite – awaiting offer of service

14-15 Drain Clearing Proposal

• Plan to review all drains within the catchment
• Budgetting $70k for drain clearing
• Anticipated mixture of spraying and

excavating

• Handouts

Environmental Issues

• End of the ox-bow lake

was formed a few days prior to the June storm, initial reports indicate that it has remained intact.

• Ngati hau, Landcare

Trust to plant out later in year

Environmental Issues

Hikurangi Plains Water

• OPUS / E Smeath

Waikato Regional Council Flood Management Seminar

May 2014

Waikato River lowering

• Removal of sand and metal has been encouraged

got up to 1,200,000 cubic metres per year

• Meant river dropped
• Now being maintained ~ 150,000 m3/yr
• Has affected lakes and ground water tables
• Eg lake Waahi (near Huntly)
• Put in weir to keep levels in lake high and control

gate to stop flooded river back filling lake

River level dropped ~ 1.5m

Lower Waikato Flood Protection

• 2002 project Watershed developed to improve

flood protection

• Integration of many TLA’s roles into one under

Waikato Regional Council

• Pump stations upgraded as many were unsafe to
• perate and maintain. Switch gear and weed

clearing biggest issues

River level dropped ~ 1.5m

Blairs Pump Station before and after

Waikato River Flood Retention – Lake Waikare

Waikato Flood Retention – Lake Waikare

Waikato Flood Retention – Lake Waikare

Waikato Flood Retention – Lake Waikare

Waikato Flood Retention – Lake Waikare

Waikato Flood Retention – Lake Waikare

Waikato River – Clearing debris

Peat Settlement

• Farmland on old wetlands made up of many metres

depth of peat

• Drainage of the peat allows it to break down and

disappear

• 10mm up to 100mm per year if cropped
• This lowers the catchment level and reduces the

drainage slope

• Pump stations become less effective as they become

too high to lower the water level.

• Example from Motukaraka

Waikato Flood Retention – Lake Waikare

Waikato River – Clearing debris

Waikato Flood Retention – Lake Waikare

Waikato River – Clearing debris

Thames flood protection

• Large thunderstorm 2002 decimated parts of

town… some gauges recorded 125mm in < 30 minutes

• Bottlenecks in stream mouths widened and

flood protection barriers built

Stop bank repair

• Ngatea stopbank failed as space between river

and stopbank (the berm) too short

• Had to widen berm to allow stop bank to be

rebuilt.

• Difficult to widen berm as banks very muddy and

rocks just slip into mud if not supported

• Used “pins” of macrocapa logs to strengthen bank

and then put a branch mattress on. Stones then placed gradually on mattress to build berm

Paeroa Main Drain Paeroa flooded when power went out in big storm and pumps failed 2 * 385kVA generator put in to replace electrical supply Save lots in electricity tariffs

Application to WDC

• Capital works funded via depreciation – allows

better planning

• H&S priority – Hika audit?
• Asset management approach based on good

data

• Consider peat issues in Hikurangi swamp
• More resource to manage issues

AOB