MIDI seeks coastal protection for tower block after cave collapse

MIDI claims natural causes for cave collapse but ERA hints at damage done during past developments and calls for public access • MIDI says apartment block is built on 'solid, proper, and adequate foundations'

Updated with MIDI explanation

A natural limestone coastal cave at the basement level of MIDI’s Q2 tower block has collapsed because of “natural processes of weathering and erosion”, the MIDI developers claimed in a project development statement to proposed new coastal works to protect their property from wave action.

According to the PDS, the site now earmarked for the stabilising works “until recently… hosted a coastal cave naturally cut in the lower globigerina limestone shore”.

The 14-storey high Q2, built on top of the cave, was approved in 2012 when the cave was still in place.

MIDI’s project development statement refers to “a natural process of erosion” through which “this cave was eroded until it collapsed, revealing the concrete basement wall of the above-mentioned Q2 tower block, thereby exposing it to wave action”.

This exposure to wave action “has led to accelerated deterioration of this reinforced concrete wall”.

The proposed works propose the stabilisation of the dangerous rock slope, the repair of the deteriorated concrete wall, and the construction of a wave dissipation slope at the Qui-Si-Sana coastline, Sliema.

The proposed coastal engineering structure, impacting 135sq.m of land, will extend more than 15 metres away from the coastal zone, while the finished top level would be 5.6m above mean sea level.

The site in question along Tigne seafront
The site in question along Tigne seafront

The application proposes two different alternatives: either a wave dissipation slope constructed of natural rock boulders, or a slope constructed with precast concrete.

What remains of the natural coast in the area is closed by a gate as well as barriers and is inaccessible to the general public.

According to the Environment and Resources Authority, such inaccessibility and the associated lack of public awareness of the natural coast and its features, “seems to have contributed to the significant physical damage inflicted to the site due to past developments, including the complete obliteration of two sizeable coastal caves, one of which was replaced by the sea-wall which is the subject of this application”.

ERA is calling for the re-instatement of public access to the coast, as also required by the North Harbour Local Plan.

But the ERA has also concluded that environmental impacts from the proposed development are unlikely to be significant and an environmental impact assessment is not required. Instead ERA has called for a marine environment study to assess the impact on any benthic habitats in the area.

Until recently the site hosted a coastal cave naturally cut in the lower globigerina limestone shore. Through a natural process of erosion this cave was eroded until it collapsed, revealing the concrete basement wall of the abovementioned Q2 tower block, thereby exposing it to wave action. Such an exposure has led to accelerated deterioration of this reinforced concrete wall.

MIDI reacts: Apartment block built on solid foundations

In a statement released on Tuesday, MIDI said the Q2 apartment block is built on “solid, proper and adequate foundations that took into consideration the geology of the area”.

The company said that the foundations of the apartment block were founded at a level “significantly below the level of the fissured rock surface and some distance (more inland) than the same fissured rock and sea cave”.

“The design of the foundations was based on pile foundations for the column positions, with piles driven to circa 9m depth, that is, well below the level of the fissured rock seen above sea level,” the company explained.

The company was reacting to concerns raised by readers in the wake of the news report that flagged the cave collapse and MIDI’s application for remedial works to protect the coastal part.

MIDI added that the seaward rock outcrop/west cave recently collapsed due to the natural process of erosion caused by the action of the sea.

“This has no impact on the structural integrity of the Q2 apartment block and the underlying basement, as the structure was designed to act independently of the surrounding geological conditions,” MIDI said.

Referring to the planning application for coastal protection measures, MIDI said this relates to remedial works to protect the concrete basement wall underlying the perimeter of the walkway in front of the Q2 apartment block.

“The works MIDI is proposing to carry out, at its sole cost, involve the repair and protection of the concrete basement wall and the placement of hardstone boulders and armour units to form a wave dissipation slope to mitigate the impact of the wave’s during north easterly storms,” the company said.

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