Roof garden on top of Gas place car park?

This post is inspired by a comment I put onto Connetable Simon Crowcroft's blog. Many thousands of people (12, 14, 16? I forget - I got quite sunburnt collecting some of their signatures) signed a petition agreeing that Gas place should be a town park with an underground car park.

I am fairly sure that the powers that be have told us that it would be too expensive to decontaminate the land, which has toxic residues beneath it from the old gas works so they reckon that an underground car park is "out of the question". I'm not sure how they can think of other developments on the site - surely it would still need expensive decontamination? They can't use the same excuse twice to different effect depending on what is being proposed, surely? Mind you, this is Jersey....

Given that the peoples' preferred solution looks unlikely, I like “Tony the Prof's” roof garden suggestion (the first comment on Simon's post). A two to three story car park, recessed slightly underground with a humongous, paradisiacal, glorious garden/park/Eden on top could work brilliantly.

Imagine being up on a level with the rooftops of St Helier - cor - what a sight!
Bert the chimney sweep (Dick Van Dyke) in "Mary Poppins" made the smoky rooftops of old London town seem magical - up there in Connetable Crowcroft's Eden one would be isolated from the traffic and the humdrum. Anyone been to Central Park? Looking around at crazy New York city, surrounding the fringes of the park, yet feeling very isolated from it, is a very nice experience.

Maybe we could recreate something like that here? Ok, so this is Jersey, so it would be in miniature but we could make it cuter.

I have excerpted a few paragraphs from a Telegraph article (click link) on roof gardens in London including the gardens that "Tony the Prof" mentioned which are the largest in London at about an acre and half in size - we could almost match that at Gas Place.

"With the air heavy with the scent of jasmine and roses, and the sound of trickling water masking the traffic, I felt thousands of miles, and years, from modern London."

"Laid out in the 1980s in a re-interpretation of the four-fold garden or Chahar Bagh of ancient Islamic architecture, the geometric design revolves around a central fountain fed by four rills that symbolise the celestial rivers flowing with water, honey, milk and wine. Four further fountains are set in the pale granite, with planting in shades of white and blue against green and silver-grey foliage including silver, weeping pears and cylinders of evergreen Ilex aquifolium."

"The central open space, which is sensitively lit for evening functions, is enclosed by high walls cloaked in scented climbers, with potted white oleanders flanking the entrances. Only when I raised my eyes to the sky did the three domes of the V&A, the Natural History Museum and the Brompton Oratory remind me of my bearings."

"Other notable, London roof gardens participating in the scheme include the famous Roof Gardens in Kensington, created above the former Derry & Toms department store in the 1930s and one of London's most surprising horticultural treats.

The place is huge for a roof garden, almost one-and-a-half acres, and divided into three oddly incongruous areas: a Tudor-style Rose Garden, a Woodland Water Garden with Japanese-inspired bridges and bamboos and populated by pink flamingos, and the spectacular Moorish Water Garden with its mature palms, kitsch cloisters and exotic planting. In spite of the fact that the soil is only three feet deep, nearly 500 varieties of trees and shrubs thrive in the highly artificial conditions, aided, no doubt, by the fact that aphids and many other pests are unable to survive at this altitude."