Chapel Riverside represents the first scheme where we have partnered with a local authority.

The site is located a stone's throw from the city's Ocean Village but requires considerable regeneration. While the scheme is technically challenging, progress is running to plan with the team on target to deliver 457 homes over the next six years.

The Chapel Riverside scheme demonstrates how we can deliver significant schemes in collaboration with local authorities. The regeneration site was secured through a development agreement with Southampton City Council, with the aim to provide high-density housing to an area close to the attractive Ocean Village development. The Council continues to own the land and grant us a phased 999-year lease. The development agreement allows us to retain a fixed mark-up on all costs from the profits generated by the development. Any surplus profits above an agreed threshold will be shared between ourselves and the Council.

We undertake careful consideration of the requirements of the community when planning developments and this project is no exception. A number of benefits will be delivered to the community on completion. Currently, the area fronting the River Itchen is all in private ownership. As a result of this project, the waterfront will become accessible to the general public through the inclusion of a riverside walkway and parks in our development. Additionally, the development will contain a 3,600m2 plaza which will be open to the public.

The scale of the project is considerable and will take six years to complete. Construction of phase one commenced in September 2017 and is due to complete in October 2018. This phase comprises 72 units, all of which (except two show homes) were sold or contracts exchanged at the year end. The construction of the sea wall (phase two) is well underway and should complete in September 2018. Phase three has just commenced and is expected to complete in 2020 with delivery of the remaining phases through to 2024.

In addition to the construction of the dwellings, there is quite a high element of civil infrastructure investment required which is expected to cost approximately £10m. This includes the construction of a 210 metre long sea wall and the relocation of three existing water settlement tanks as well as substantial archaeological excavation.

Challenges

Archaelogical works

Archaeological works were undertaken for a period of 13 weeks from January 2017. A 12th century chapel was demolished above ground level in 1964. We undertook extensive excavation work to expose the remains and recorded every aspect. Much was learned about the way the building was used; from when it changed as a chapel to a tide mill and then one of the first steam driven mills in the 18th century. The site held strategic importance in piecing together the final area of what was the Saxon settlement of Hamwic. Our site is on the line of the old Saxon shore and Hamwic. Various finds of medieval pottery, waste pits and other items were discovered.

Site contamination

Originally the site contained the Council's waste and recycling centre, highways division premises for maintenance of refuse vehicles and storage of salt and grit for the roads and a Council double glazing factory. All these activities have contributed to the contamination of the site, including hydrocarbon pluming and asbestos and have to be dealt with as part of the project. Additionally, during site investigation work an old quay previously used for unloading and storing lumber was found to have been filled in together with two mill ponds on other parts of the site. Both of these required complex ground engineering solutions. The reclaimed land build-up does not offer bearing pressures to support any foundation other than a piled solution.

The old quay wall will need to be grubbed out to remove any obstructions within the ground. Any hydrocarbon contamination will be remediated on site and the soil re-used.

Water settlement tanks

The pump house on site handles one-third of Southampton's waste water. In addition, there are three large open air storm water settlement tanks which have to be relocated on the site as part of the project. Lengthy negotiations have taken place with Southern Water and the current proposal is to build an 18-metre deep precase concrete shaft which will use less area and therefore release further land for development. In order to retain control over time and budget we are designing and building this ourselves rather than having to rely on a third party.

Sea wall

The project borders the River Itchen and as can be seen from the site diagram above, the sea wall covers almost half of the boundary of the site and is an extensive undertaking. It is 210 metres long with the outer wall requiring the sinking of 16-metre steel sheet pile walls with an inner wall of nine metres connected by over 100 four-metre steel tie rod bars.

In order to finalise the design of the wall, negotiations were held with the Crown and the Marine Management Organisation as well as the local authority and will form part of the Southampton Strategic Flood Defence. Construction started in January 2018 and will be completed in September 2018 at a cost of over £2m.

Construction phases

Phases of build

1. 72 plots1

2. Sea wall

3. 132 plots + commercial2

4. 38 plots + commercial

5. 132 plots

6. 83 plots + commercial

1 Construction commenced September 2017 completing October 2018.

2 Construction commenced July 2018.

Construction of the sea wall

Construction of the sea wall.