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 an issue found internationally. 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.

Challenge

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.

Solution

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

Results

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