bubble curtain

Test installations of bubble curtains showed massive noise reduction from underwater blasting with charges up to 1800 kg TNT.

The Norwegian Coastal Administration; Kystverket, had decided to do scientific testing of the effects of bubble curtains on underwater noise.  They did the testing in connection with real life underwater blasting works in the harbour of Ålesund on the Norwegian West Coast.

For the testing, I calculated and constructed a 75m test installation with an air flow of 375 l/s.  The test bubble curtain was placed in different shapes, and the noise mitigation was tested in connection with the blasts.

The  testing was carried out by the french specialist company Quiet Oceans.  The results was convincing, the best constellation showed a noise reduction of 32 dB.  Take into consideration that the dB scale is a logaritmic scale, where a 3 dB reduction means a halving of the noise.

The report from the testing gives us a good documentation that the bubble curtains really are a good measure for underwater noise  mitigation, protecting marine life from negative effects of noise from underwater blasting, pile driving and other noisy human activity in the water.

Read the full report from Akvaplan-Niva and Quiet Oceans here:  REPORT ASPEVÅGEN

See the bubble curtain and blasting video here:

Nils Paul Mehren

Underwater blasting
Photos by Kystverket/Dronefoto Ålesund Håkon Longva Haram