LEIPZIG, Germany (Reuters) - Plans to dredge the river Elbe in Hamburg must be improved before a stop order on the work is lifted, a German court ruled on Thursday, raising the risk of more delay to work to deepen Germany's biggest port and open it up to new container ships.
Green pressure groups had lodged a legal complaint against the original plan, arguing the environmental impact of dumping mud and sand on fragile coastal wetlands would be devastating.
Following the ruling from Germany's top administrative court that authorities must do more to protect the river's maritime environment, shares in Hamburg port terminal operator HHLA were down 11.5 percent at 1215 GMT.
The Hamburg city government said it was pleased the court had in principle accepted that dredging can take place.
"We have at least legal security," said the city's economy minister Frank Horch. The planning application must be amended but "there is no doubt" that the dredging will take place, he said in a statement.
Hamburg wants to make it easier for new large container vessels to reach the port regardless of the tide to counter intense competition from Rotterdam, Antwerp and Bremerhaven.
Despite the river having been deepened six times already, some of the largest ships face a costly wait for high tides to dock in Hamburg and the city fears shipping lines will switch to other ports if the Elbe is not dredged further.
The court ruled that although parts of the planning process were incorrectly handled and broke planning law, this should not in principle stop Hamburg getting consent to dredge the river.
The association of Hamburg port companies UVHH said it regretted that the court had not removed a stop order on the dredging.
Authorities must now take rapid action to resolve the deficiencies in the planning process, especially involving damage to water quality from the dredging, it said. If immediate action was taken a supplementary planning permission process for the dredging could be completed in 2018.
A successful conclusion of the dredging application is essential "so that the port of Hamburg, Germany's largest harbor and one of Europe's most important ports, can still play in league division one," said UVHH president Gunther Bonz.
The city of Hamburg and federal waterways authorities want to dredge about 130 kilometers of the river so that ships with 14.5 meters draught can reach the port, against 13.5 meters now.
Ships have grown from carrying 2,000 to 3,000 standard twenty foot cargo containers (TEU) in the 1980s to carrying up to 18,000 containers and vessels of 20,000 TEU are being built.
Writing by Paul Carrel and Michael Hogan; Editing by Alexander Smith and David Evans