Fate of Harq Hammiem cave still unclear

A report by the Environment and Resources Authority drafted in April has warned that the risk of subsidence in the large subterranean cavern at Harq Hamiem, just off St George’s Bay, posed by high-rise development remains unclear, and further studies are needed to establish the impact of vibrations on the geology of the area.

“The project may lead to subsidence of the roof on the large subterranean cavern at Harq Hamiem,” a screening report by the ERA on the proposed developed on the former Institute of Tourism Studies site said, adding that “the risk of subsidence on the large subterranean cavern at Harq Hamiem is currently unclear”.

The ITS site will be developed by the db Group after securing a government concession for the land.

The proposed development includes a 5-star hotel with 455 rooms, 158 residences, commercial office space, shopping mall, casino and restaurants and a basement car park.

But according to the ERA, further studies on geomorphology, hydrogeology, water quality and cave ecology are required in a forthcoming Environment Impact Assessment.

According to a project development statement presented by the developers, plans have already been modified to protect the caves by pushing the hotel more to the east, with the western wing of the original proposal completely removed, in order to avoid “imposing excessive loading in the area of Ghar Harq Hamiem”, which is located on the western part of the site.

The ERA report notes that the proposal is partially located above the Harq Hamiem cave system, a scheduled Level 1 Area of Ecological Importance and Site of Scientific Importance 

The proposed development includes a 5-star hotel with 455 rooms, 158 residences, commercial office space, shopping mall, casino and restaurants and a basement car park

The development, located in St George’s Bay, will cover a total site area of 23,975 sq.m with a total gross floor area of 115,352 sq.m and split into three areas. Site A, measuring 5,536 sq.m, currently an open site, is earmarked for car parks. 

Site B, measuring 18,202 sq.m, which is the area around and including the current ITS building, will include the  residential tower, shopping complex, hotel, and surrounding amenities such as conference facilities, restaurants, Hard Rock Café, nightclub, casino, spa and fitness facilities, public plaza, swimming pools and a wedding reception hall.

Site C, measuring 237 sq.m, is a small site located next to the coast and adjacent to the Marina San Gorg Hotel. 

This will include a lido Structure for the provision of amenities (food prepared off site, umbrellas and sunbeds).

The Harq Hamien cave

The cave is the only known fully submerged terrestrial cavern in the Maltese islands and is inhabited by the rare albino shrimp.

Any proposed development in the buffer zone of the cave has to be assessed in terms of their potential impact on the “stability and geology of Ghar Harq Hamiem”.

The original draft of the North Harbour Local Plan in 1999 identified Moynihan House as a site for a car park, but the project was abandoned following a detailed study of Ghar Harq Hamiem, which revealed that the cave was far larger than originally thought.

The cave was found to open up and the water in it reached a depth of 52 metres below sea level. The surface of the water was found to be at a depth of 16 metres below sea level.

The studies led to the discovery of a passage connecting the first chamber to a deeper chamber closer to the tourism institute training school.

The stability of Ghar Harq Hamiem is related to the thickness of its roof. “The roof is over 30 metres thick in the deeper chamber, which makes it relatively safe,” geologist Peter Gatt had told MaltaToday in 2016.

According to Gatt the cave may have reached some form of equilibrium and could be “relatively stable”. However, “further studies need to be carried out to assess the stability of the cave”, he said, when asked whether the cave could be impacted by excavations in the area.

Gatt pointed out that the extent of Ghar Harq Hamiem is known and the cave has been mapped. Gatt also insists that no excavation of rock should be carried out directly over the cave roof.