Estimate your dredging impacts with more certainty

Estimate your dredging impacts with more certainty

See how New Zealand’s largest port of Tauranga did it with a customised web-based solution


Managing dredge projects to minimise environmental impacts is a global concern. A large dredging operation of our client, Rohde Nielsen A/S – for New Zealand’s largest port of Tauranga – required strict limits on the turbidity during channel works. DHI worked with Rohde Nielsen A/S to provide a tool which estimated the turbidity level expected in the surroundings for any given dredge scenario with a combination of other dredging activities. This allowed operators to plan and execute dredging scenarios to estimate environmental impacts with more certainty.



Rohde Nielsen A/S was required to meet specific turbidity consent limits to ensure that the harbour maintains environmental standards for recreation and tourism. They required a resource for carrying out optimal project planning and considering dredge scenarios with expected turbidity levels within acceptable values. All within a tight deadline.



Rohde Nielsen A/S worked with DHI to swiftly produce a web-based tool, which significantly contributed to the overall success of the dredging project. Solution highlights:

  • Rapid assessment of environmental impacts based on predefined conditions
  • Only requires a relatively low web server load
  • Extremely informative inputs allow for optimal sequencing of dredging works, with the environment as the key element
  • Effectively minimises the impact of the dredge operations on turbidity levels


Rohde Nielsen A/S successfully managed to complete the one-year dredging contract well within budget and time without a single breach of turbidity response level. The works were executed on time, in full compliance with the defined turbidity limits on all three-trigger levels and to the fullest satisfaction of all stakeholders.

  • More certain assessment of environmental impacts of the dredging operation
  • Reduction in turbidity levels after having fulfilled consent limits requirements
  • Operational savings due to minimising breaches of turbidity levels


Rohde Nielsen A/S


New Zealand

Related SDG(s):

SDG 14: Conserve and sustainably use the oceans, seas and marine resources for sustainable development


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‘The scope of work was executed on time, in full compliance with the turbidity consent limits on all three trigger levels and to the fullest satisfaction of all stakeholders.’

Ingolf Gudjonsson
Project Manager
Rohde Nielsen A/S

About our client

Rohde Nielsen A/S is a privately owned global marine dredging contractor. Operating from Denmark, the company owns and operates a fleet of 43 specialised dredging units, moving annually some twenty five million cubic meters of material. Rohde Nielsen A/S ranks number ten in a listing of the largest dredging companies in the world. It ranks number five in the listing of globally operating dredging companies.

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