update - a road tunnel below Åboulevard and then on below HC Andersens Boulevard
/Åboulevard in the late 19th century looking north with the river still at the centre
Bethlehem church designed by Kaare Klint was completed in 1938 but the apartment building dating from around 1900 is on the right on both the historic view and the photograph of Åboulevard now
A proposal for a major engineering project, to construct a traffic tunnel down the west side of the historic city centre, is now in doubt.
It would take underground much of the traffic that now drives along HC Andersens Boulevard, on the west side of the city hall, and is part of a plan to remove the elevated motorway at Bispeengbuen - bringing traffic into the city from the north - and this would make it possible to reinstate a river that flowed into the lakes that now flows through a covered culvert below Åboulevard.
From Jagtvej, at the south end of the elevated highway at Bispeengbuen, and following the line of Åboulevard to the outer side of the lake, is about 1.6 kilometres and, from the lakes, a tunnel running between Jørgens Sø and Peblinge Sø and on along the line of Gyldenløvesgade to Jarmers Plads and then down the full length of HC Andersens Boulevard and then under the harbour to Islands Brygge is another 2 kilometres so, including the proposed tunnel at Bispeengbuen, that would be between 4.5 and 5 kilometres of tunnel in total.
For comparison, in Oslo, the Festning tunnel - opened in 1990 to take traffic away from the square in front of Oslo city hall - and then an extension to the east - the Operatunnelen completed in 2010 - form, together, about 5.7 kilometres of underground motorway.
The landscape and architecture studio Tredje Natur and the engineering specialists COWI have drawn up a feasibility study for the proposed scheme for the finance directors of the city and of the municipality of Frederiksberg - the road runs between the two areas.
Reinstating the river and extensive landscaping would be an important part of storm water protection for the low-lying areas of Frederiksberg with planting, surface drains, and culverts controlling storm floods before taking it away from the area in substantial storm drains in the bottom half of the tunnels below the road decks in the upper half of the tunnel.
Tredje Natur have produced drawings for the planting that would be possible along HC Andersens Boulevard if the heavy traffic that uses the road is taken down into a new tunnel. There could be a narrow road for local traffic, an open water course and extensive planting.