Coastal defence improvements at Tipner Lake
New coastal defences are being built as part of the North Portsea Island Coastal Flood Defence Scheme which have been designed to reduce the risk of coastal flooding and erosion to the area over the next 100 years.
To increase the flood risk management in this area, the seawall height will need to be increased by approximately 1.4m from the current levels. Increasing this wall height will afford the properties in the area greater protection against coastal flooding, reducing the probability of flooding, by increasing the Standard of Protection to a 1 in 500 years, one of the highest in the country outside London.
This phase of the works will be from the Mountbatten Centre, Twyford Avenue to the Ports Creek Roundabout and will form Phase 3 of the North Portsea Island works. Construction is due to start in April 2017, with completion planned for Autumn 2019. The start of the works for this scheme was at Anchorage Park and completed in August 2016, then the Milton Common works took place and were completed in October 2016. The remaining works will be under construction until 2022.
The existing sea wall along this stretch of frontage is in varying condition, in some places poor, and is too low to provide adequate flood protection to the area behind. In 2014, we engaged with the local community as to the preferred structural option in the area. Following feedback from this, the works will include concrete encasement of the existing wall, and in some sections, rebuilding of the existing sea wall with a new wall to provide improved defence over the next 100 years.
There is extensive landscaping and planting designed for the land behind the wall which includes new footpaths, attractive planting designs and several social spots with seating where visitors can pause to enjoy the views of Portsmouth Harbour and the revived parkland. The coastal path will be replaced by a new 4 metre wide shared use path which will run the full length of the new wall and a network of gravel paths behind the defences will further add to the enjoyment of the area.
What is happening on site?
In April 2017 we arrived on site and began the set up works. These included building a new temporary haul road between Alex Way and the main compound located at the north-western corner of Alexandra Park. This road and the compound will remain in place until autumn 2018 when they will be removed and the area returned to use as playing fields.
Once the site was established we began construction of the final sea defences. This has included driving several hundred steel sheet piles that will form the foundation of the new walls. When the concrete wall is in place, these piles will be cut down and buried under the foreshore.
Over the coming weeks we shall be continuing to drive piles and starting work on the concrete elements of the wall. The reinforced concrete wall will be built in-situ using concrete brought in by road so there will be a number of concrete wagons delivering to site. However, due to the tidal conditions and the physical restrictions of the site there is a limited volume of concrete we can pour in one day, so the number of delivery wagons will be similarly limited.
When will it happen?
How will it affect me?
The construction site will be set up to ensure public safety and allow the work to progress in a safe, efficient and controlled environment.
As the site set up began in April 2017, one of the first tasks being to set up fencing along the site boundary. During the work there will be no access to the areas within the site boundary, however alternative informal routes will be available throughout construction and these are clearly signposted around the site. Please note that these informal routes are not on surfaced paths so will not be suitable for all users.
Temporary Cycle Path Diversion
A formal diversion will follow Northern Parade for the three years of works. Local access and diversion routes will be available around working areas where possible.
Please click here to see the cycle diversion map if you are unsure of the cycle diversion path.
The coastal footpath between Mountbatten Centre (Twyford Avenue) and the Ports Creek Roundabout will need to be closed while work is taking place. This means that the public cycleway and footpath along Tipner Lake will be out of use during construction, with diversion routes provided.
We are working closely with local groups and the Portsmouth City Council Highways team to establish a suitable alternative route during this period.
Lower Wade Way
The Lower Wade Way causeway has now been removed and its footprint will return to intertidal mudflat.
The old causeway structure was approximately 285m in length, old and in poor condition. Maintaining this length of slipway can be costly and often encourages unwanted fly tipping in the area.
Upon completion of the new seawall a new slipway will be constructed in the same location to maintain access to the foreshore and it will be much shorter than before and still allowing tidal foreshore access. For further information on this, please follow this link.
For additional information, please see our posters.
If you would like any further information, please email email@example.com.
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