miketsp
Contributor
Down here in south east Brazil there is a public argument going on about a planned dredging operation at a naval shipyard at Angra dos Reis in the bay of Ilha Grande.
The shipyard won a contract to build two large oil rigs P-51 and P-52 for Petrobras but they have a problem in that the depth on the approaches to the port is only 7m. The rigs cost 600 million USD each and should generate about 5000 jobs during 2 1/2 years..
So they need to dredge out a 200m wide channel, 11m deep and about 1200m long which means shifting 520000 m3 of sediment.
The problem is that they want to dump 80% (point A) inside the bay and only 20% (Point B) 18km outside the bay in deeper water.
The shipyard representatives say that 80% of the sediment goes directly to the bottom and the rest takes up to 72 hours to settle. But the operation is planned to last 120 days.
Now Point A is only 5 km from "Parcel dos Meros", a traditional dive spot.
This bay is one of the most dived spots in Brazil, with 8 local dive operators and many others visiting every weekend.
Most of the year, divers make up the vast majority of the visitors so the local tourist operators are naturally very worried that there is going to be a hole of at least 4 months with no visitors and there could be permanent damage to the corals and marine life.
Even the Point B outside the bay has the local fishermen worried about the impact on shrimp & other fishing.
The local community wants the use of a Point C, even further out, beyond the 80m depth line.
Has anybody any comments on similar situations and what was the medium term impact of dumping such a large volume of sediment into a very active marine environment?
The shipyard won a contract to build two large oil rigs P-51 and P-52 for Petrobras but they have a problem in that the depth on the approaches to the port is only 7m. The rigs cost 600 million USD each and should generate about 5000 jobs during 2 1/2 years..
So they need to dredge out a 200m wide channel, 11m deep and about 1200m long which means shifting 520000 m3 of sediment.
The problem is that they want to dump 80% (point A) inside the bay and only 20% (Point B) 18km outside the bay in deeper water.
The shipyard representatives say that 80% of the sediment goes directly to the bottom and the rest takes up to 72 hours to settle. But the operation is planned to last 120 days.
Now Point A is only 5 km from "Parcel dos Meros", a traditional dive spot.
This bay is one of the most dived spots in Brazil, with 8 local dive operators and many others visiting every weekend.
Most of the year, divers make up the vast majority of the visitors so the local tourist operators are naturally very worried that there is going to be a hole of at least 4 months with no visitors and there could be permanent damage to the corals and marine life.
Even the Point B outside the bay has the local fishermen worried about the impact on shrimp & other fishing.
The local community wants the use of a Point C, even further out, beyond the 80m depth line.
Has anybody any comments on similar situations and what was the medium term impact of dumping such a large volume of sediment into a very active marine environment?
