The past 12 months have been relatively wet with about 60% more rainfall than the district typically experiences – water levels up around 1,000mm have occurred when we typically get about 650mm.
Groundwater levels have been high across the district and the undercurrents have been flowing in the Mandeville area since July 2017. We have experienced two notable rainfall events in July 2017 and February 2018 which caused localised flooding.
Stormwater Drainage Works
The wet conditions have highlighted areas where drainage is problematic or where there are localised issues. In particular our coastal area has experienced extended periods of surface flooding following rainfall events. Typically Council receives around 500 drainage related service requests per year, while we received over 1,400 for the period July 2017 through to June 2018. Our Drainage team has been working hard to respond to and address all of the issues raised.
Flooding in Pervical Street near the South Belt intersection, Rangiora, February 2018.
Numerous drainage investigations have either been completed or are underway to address issues highlighted by the wet weather we have experienced. Investigation work may include undertaking CCTV inspections to confirm the condition of pipework, visual inspection of drains to check for blockages, hydraulic assessments to confirm the capacity of the system and the reporting on maintenance and/or upgrading works required.
The key areas being investigated are:
- Waikuku Beach (refer below for more information)
- The Pines Beach / Kairaki (refer below for more information)
- Woodend (James Drive, Woodend Road, Main North Road)
- Rangiora (Kingsbury Avenue, Seddon Street, Oxford Road, Carmana Gardens, Douglas Street, Belmont Avenue, Acacia Avenue, Coates Street, Whites Street, Railway Road, Newnham Street)
- Kaiapoi (Island Road, Ohoka Road, Otaki Street, Hilton Street, Bracebridge Street, Gray Crescent, Murray Place, Cridland Street West, Old North Road)
- Oxford (Matai Place, Tui Street, Weka Street, Main Street, Kowhai Street, Burnett Street)
- Mandeville (Siena Place, Roscrea Place, Wetherfield Lane, Redfern Lane)
In addition to the Council's Roading team are undertaking a number of investigations and physical works in numerous rural locations to address localised issues.
We also have a number of drainage upgrade projects that are underway this financial year as set out in the table below.
|South Belt / Southbrook Road intersection||Works to improve sump inlet capacity to commence shortly.||Complete|
|Springbrook development, Rangiora||Immediate works complete and further works currently being designed.||Design underway|
|Tui Street / Weka Street, Oxford||Installation of new soak pits.||Design underway|
|Oxford Road, Rangiora||Water race closure approved by Utilities and Roading Committee in June 2018.||Design underway|
|North Brook – Janelle to White, Rangiora||Upgrade of North Brook capacity.||Design to be tendered|
|Siena Place / Sillano Place, Mandeville||Drainage improvements.||Design completed|
|Main Street, Oxford||Installation of new pipework.||Design underway|
|King Street, Rangiora||Improve drainange outside Police Station.||Not started|
|Feldwick Drain catchment improvements||Improve drainage in Beach Road / Williams Street and Kaiapoi East area. 2018/19, 2019,20 and 2020/21.||Strategy underway|
|Roscrea Place / McHughs Road, Mandeville||Capacity upgrade - 2019/20 and 2020/21.||Investigation complete|
|Johns Road, Rangiora||Capacity upgrade - 2020/21 and 2022/23.||Not started.|
A number of drains and culverts in the Kings Avenue/Allin Drive and Park Terrace drain have been cleaned to improve the drainage from the western end of Broadway Avenue and Kiwi Avenue.
Upgrade and reconstruction works scheduled to be carried out in April:
- Swindells Road - culverts and swales
- Reserve Road - culverts and swales
- Kiwi Avenue Recreational Reserve - pipes and soak pits
- Kings Avenue/Allin Drive - drain and culverts
- Allin Drive - culverts and swales
Further investigations to be undertaken:
- Broadway Avenue
- Waikuku Beach Central Area – localised flooding
- South Oval – localised flooding and culvert/pipe upgrades
Taranaki Stream Floodgate:
Environment Canterbury are planning to undertake maintenance work on the Taranaki Stream downstream of the flood gate in February this year. The work will improve drainage of water from behind the stopbank. This area sits within the Coastal Marine Reserve and Ecan is currently liaising with DoC to ensure that the damage to the surrounding environment is limited as far as practicably possible. Once this work is complete further work is planned to be undertaken on the flood gate itself to replace the seals. As a temporary measure, Ecan staff have been manually operating the gate to allow the maximum volume of water to pass through to help reduce water levels upstream.
The Pines Beach / Kaiaraki
In The Pines Beach and Kairaki area, 12 locations have been identified that need to be investigated:
- Pines Oval Community Hall - localised ponding
- Pines Oval Playground - no positive drainage
- Batten Grove / Monks Parade - localised flooding
- Batten Grove / Chichester Street - drains and culverts
- Chichester Street to Kairaki Creek - drain and culverts
- 39 Dunns Avenue to Kaiaraki Creek - drain and culverts
- 74 Dunns Avenue - drain and culverts
- 86 Dunns Avenue - drain and culverts
- Beach Road - stop bank and flood gate
- Beach Road - flooding at old motel
- Kairaki Yacht Club - drainage from car park
- Kairaki Campground - drainage swale
Survey work has been undertaken and pipes in Chichester Street and Dunns Avenue have been cleaned out and CCTV inspected. The pipes and drains at the old motel on Beach Road have been cleaned out. Initial works along Batten Grove and Chichester Street have been completed which has improved drainage in this area. Investigation is currently underway into options to address the flooding in the vicinity of the playground Pines Oval Playground.
Initial work along Batten Grove and Chichester street is completed.
If you would like to know more about any of the above drainage works, please contact the Councils drainage team on 0800 965 468.