Ideas floated in addition to sinking the A4 included raising Stamford Brook to the surface; using space under the A4 elevated section to create new pedestrian boulevards; the rejuvenating of Apollo Square and St Paul's Green; and using dead Council-owned space to open out a real approach to Hammersmith Bridge.
The architects argue that sinking the A4 would allow the reconnection of the communities cut off from the river since its construction in the 1920's.They also said, interestingly, that while it would cost around £4,000/sqm to lower the road, around £3,000/sqm could be recovered from the development rights for the 'new' space created at ground level.
One of the schemes, devised by Hugh Broughton Architects, called for Stamford Brook to resurface in the new plaza planned for the space currently occupied by the Town Hall extension which will be produced by the Helical Bar/Grainger King Street scheme.
Adam Knight, of HBA, said raising the Brook, (which chimes with a recent Mayoral statement about raising rivers all over London), and running it to join with Hammersmith Creek - also raised to the surface - down Nigel Playfair Avenue to the river would remind people of the presence of the Thames just a couple of hundred yards away.
While recognising that the idea of a bridge over a newly sunken A4 carrying water on a symbolic aqueduct would not be the cheapest scheme to realise, Knight said: "A version of this where the connection to the river is by a surface level crossing across the A4 would not only be cheaper than (HelicalBar's) proposed Bridge into Furnival Gardens, but more likely to restore the river connection. People will be much more inclined to go to the river by a surface level route, than to climb two storeys".
Helical Bar's proposed bridge involves raising the level of Nigel Playfair Avenue to around the second floor level of the listed Town Hall building, continuing at that level over the A4, and consuming 120m of Furnival Gardens for the down ramp on the south side of the A4.
Alex Lifschutz, who co-ordinated the workshop, supported HBA's ideasstrongly: "I've spoken to a respected transport adviser, who says surface level crossings of the A4 at this point are perfectly feasible."
Both Hammersmith Society (who have opposed the idea of a bridge from theoutset) and Hammersmith Historic Buildings Group supported the proposals.
Nine Hammersmith architecture practices collaborated in the workshop on June 23, which was part of the London Festival of Architecture. The workshop was the key activity in the 'Hammersmith Satellite Hub' for the Festival, who's five main hubs are all in Central London.
The practices involved were:
Chartered Practice Architect
Hans Haenlein Architects
Hugh Broughton Architects
The Manser Practice
Barroll Webber Architects
Powell Tuck Associates
Lifschutz Davidson Sandilands
The architects all indicated their willingness to continue working collaboratively to generate ideas for the improvement of Hammersmith, a suggestion which the Council representatives were pleased to receive, and will hopefully act upon. It would certainly be a good thing if such workshops continue.