The Italian authorities plan to expand Venice's port into a bustling shipping hub, further endangering the fragile lagoon the sinking city is built on, a conservation group has warned. Venice in Peril, a British fund that works to preserve Venice, said a report it had obtained from the local port authority showed plans to accommodate more, and bigger, ships in an attempt to compete with other European harbours. The report, drawn up for the Italian senate, outlines ongoing and future works, including the continued dredging of passages in the shallow lagoon to allow larger vessels in and the construction of a new shipping terminal in the long-declining mainland industrial zone of Porto Marghera. The port authority is spending at least �260m (�230m) on dredging inlets and navigation channels to allow the passage of ships of up to 400 metres (1,300 feet) in length. This is particularly alarming for conservationists because dredging and heavy shipping traffic are seen as one of the causes of the rising sea level in the lagoon, which threatens the low-lying islands on which the historic city is built. Under the combined effect of rising water levels and settling of the land, Venice has sunk 23cm (9in) in the last 100 years. Most experts agree that the waves generated by large ships and the currents that run through the deep passageways play a big part in the rising water levels, displacing and dragging out to sea the sandbanks and other sediments that help protect the city. In winter, Venice periodically goes through bouts of acqua alta (high water), when strong winds and high tides conspire to push the sea into streets and piazzas, forcing tourists and locals alike to don rubber boots and teeter along impromptu bridges. The rising sea level has increased the frequency of the floods, and in December Venice suffered its worst deluge in 22 years. Experts warn the problem could further worsen in the coming decades as climate change causes sea levels to rise globally.