What are we doing?
Ned’s Creek has caused flooding issues for a number of nearby residents, so we are doing some work to reduce the frequency and severity of flooding at affected properties.
We plan to build a small levee (stop-bank) between Ned’s Creek and some of the properties on Hampden Street. The levee will extend eastwards around the recreation centre, to cut-off any overland water flow from further upstream. We are also installing a new culvert in the stream.
During heavy rain events, the levee will prevent water that collects in the paddock on the southern side of Ned’s Creek, from reaching residents properties. The new culvert will hold back any water that can’t fit in the stream channel. Once the rain has passed, excess water will drain away at a rate that the stream can handle.
Why are we doing it?
Ned’s Creek is not wide enough or deep enough to manage heavy water flows, so when there is heavy rainfall, nearby areas (the shopping and motel area next to the lower part of Fairfax Street and properties on the south side of Hampden Street) are frequently affected by flooding.
While some work has already been done upstream to reduce the risk of flooding across the Recreation grounds and into Hampden Street, more needs to be done to keep floodwaters away from properties.
How will it affect me?
The levee extends around the perimeter of the Murchison Sports and Recreation Centre. We have planned the work to avoid disruption to sporting and other fixtures (such as the Murchison A&P Show), but there will be less viewing space available for spectators while construction takes place.
Construction work is taking place on Council owned and privately owned land and the Council have already talked with property owners whose land is directly affected by this.
Other nearby properties may experience some noise, dust and vibration from the construction work during daytime hours, but we are doing our best to minimise the disruption. During the beginning of construction, some complaints were received about noise. As a result of that feedback, the contractor is now starting work later and has changed their methodology to reduce the noise impact.
The contractor has appointed a public liaison person, Dave Morris, (phone 027-446 6269) who is available 24/7 by phone to answer any questions. Dave is keeping residents and other affected parties updated by mail-box drops / door-to-door visits as necessary.
Consultation
We presented details about the project and held drop-in sessions for the community to meet the project team and answer questions. You can view a summarised table of the questions asked and actions and outcomes at the bottom of this website page.
About the project
Current status
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In construction
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Planned start date
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March 2020 |
Planned end date
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August 2020 |
Access
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Access routes to the BMX track and the Equestrian Centre will be restricted for short periods from time to time during construction. |
Contractors
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Rosco Contractors Limited |
Estimated contract cost
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$0.4m |
Maps, plans and designs
This map shows the area of works.
Click here to view a larger version.
Downloads
View Ned's creek construction issue design drawings. (pdf, 14 MB)
Contacts
Tasman District Councl Project manager
Rosco Contractors Limited Site Supervisor
- Dave Morris, 027-446 6269
Questions and Answers
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This table summarises comments and suggestions made by attendees at consultation meetings and community drop-in sessions. It does not cover issues relating to Ned's Creek downstream of the Fairfax Street Culvert.
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Issue/Task/ Opportunity
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Details
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Further Action
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Pony Club have requested a second access; a bridge for horse / pedestrian traffic at eastern end of Pony Club would be acceptable.
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Pony Club are concerned that the loss of the second access will mean that horses and vehicles will need to use the same access point at the same time. Consultant to investigate options including cycle trail bridges.
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The updated construction plan includes a new 1.5m wide pedestrian/equestrian culvert crossing east of the existing accesses to allow horses to cross to the no.2 rugby field away from vehicular traffic.
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Consider whether there is space for two large vehicles to pass side by side south of Recreation centre building
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Consultant to measure design. Steepen batter and widen access if required. Minimum sealed width ideally 5 meters.
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Consultant has updated drawings to include a widened access behind the recreation centre. The ramp accessing the widened Pony Club culvert access has also been widened to allow easy large vehicle access.
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Check all existing surface drains under levee have been identified and considered
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To consider as design finalised. Uncertainty amongst residents as to number and location of outlets, suggestion there may be 6 or more outlets, with some buried.
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We have recorded all readily identifiable outlets and have allowed contingency for others to be discovered and addressed in the course of the works.
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Murchison Community Council request that no flaxes be planted in or around the channel
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Raised at the Murchison Community Council Meeting 14.10.19
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Local experience that flaxes congest the channel and catch silt and debris, exacerbating flooding. Recreation Centre committee invited to collaborate on replacement planting plans.
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Pipe discharging to Ned's Creek at the end of Milton Street needs clearing
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Raised at drop-in session at Recreation Centre 14.10.19.
Add note on drawings.
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Contractor to ensure pipe is cleared as part of works. Note, a headwall and flap gate is to be installed as part of the works.
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Talk to Reserves and Facilities staff about providing a composting toilet at the Pony Club
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Raised by Pony Club at morning drop-in session at the Recreation Centre. Contractor for flood protection may be able to provide some earthworks.
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This project is funded by rates collected for stormwater control, so is not able to fund a toilet. Project Manager has discussed with Council Reserves & Facilities staff and there is no justification for Council to fund a new toilet. Public toilets are available nearby.
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Provide rainfall information for the 2 year design event to Hampden Street residents
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Requested at Murchison Community Council meeting, St Johns Building, 14.10.19.
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2 year event indicative rainfall totals:
24hr = 91mm, 6hr = 42mm.
Design event is a short duration event nested within a longer duration event.
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Check for pest plants in the borrow / attenuation area.
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Raised at the Murchison Community Council meeting. Topsoil will be stripped and stockpiled to be re-spread. Invasive species control to be considered in specification.
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Pest Location Inspections layer in Council's GIS system has been checked, with no record of Pest Plants in the area.
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Options to consider for future use of the attenuation area; dog park, fruit trees, wild flowers, natives, no natives, additional equestrian area, overflow parking, hemp plantings.
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Various options raised at drop-in session at Recreation Centre, Community Council Meeting, and Recreation Centre Committee Meeting 14.10.19.
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Ability to combine many of these suggestions. The Council is developing a concept plan for the area for future discussion. This workstream does not need to delay progress of the flood protection work.
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What will happen to the attenuation area after the works, and who will maintain it?
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Asked at Community Council Meeting
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The area is currently stormwater reserve and will be maintained by leased grazing. The contractor will be required to contour and sow the area in grass at the completion of works. The Council is flexible as to how the area will be maintained in future, dependent on the end use. Could be given to the Recreation Centre to manage if agreed.
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Access to attenuation area during storm will be risky.
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Consider lockable gate on levee access opposite Brunner Street
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Quite feasible, but needs discussion around when gate will be locked, and who is responsible for locking and unlocking it.
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Ask Council Hydrology team about feasibility of installing stage telemetry with automated warning system.
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Community Council indicated there would be value for the community from an automated warning system for large floods.
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Discussed stage monitoring systems with Hydrologists for the attenuation area, which is simple and cheap to provide. Providing a useful flood warning system, however would have quite different requirements. Will be investigated further.
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Request to involve Recreation Centre Committee (or their nominated person) in plant selection for re-planting.
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Raised by Recreation Centre Committee.
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The Council are consulting with the Recreation Centre Committee on development of replacement planting plans.
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Install gate in fence between BMX track and the attenuation area.
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Raised by Pony Club at morning drop-in session at the Recreation Centre, and by Recreation Centre Committee.
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Note added to drawings for installation of a gate to be included in fencing reinstatement after works.
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Why can’t the Council widen and deepen the channel past the Recreation Centre and Hampden Street?
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A number of residents suggested that digging out the channel will relieve the flooding problem.
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1. Currently the flooding issue for the Recreation Centre and eastern Hampden Street properties originates from upstream of the Recreation Centre, across the sports fields. Modelling shows that widening the channel will not provide any significant improvement.
2. The current grade and depth of the channel is defined by the levels of the culverts; we can't lower the channel without also replacing 5 substantial culverts, which is prohibitively expensive.
3. Increasing the capacity of the channel upstream of Fairfax Street will mean more water will arrive at Fairfax Street faster, increasing flooding issues for the transport yard, western Hampden Street properties and Fairfax Street businesses.
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