The environmental advantages of Dredging with Nature

As dredging professionals grapple with the challenges of environmental degradation, rising water levels and the need to reduce greenhouse gases, the need for sustainable marine dredging solutions is pressing.

There is an innovative solution that not only offers significant environmental advantages to marine dredging in ports and harbours, and is easy to deploy, adaptable and more cost-effective. By “Dredging with Nature”, Tiamat, a hydrodynamic dredger, offers a cleaner and greener method of maintenance dredging.

Our standard Tiamat is designed to be towed behind a relatively small vessel, such as workboat or multi-cat with an A frame that is between 25-27 meters. The standard Tiamat includes three pumps, two to inject water into the sediment on the harbour or sea bed and a third to extract diluted silt, pump it up and release it higher into the water column.

From reducing sediment disturbance and lowering potential pollution, to minimising habitat disruption, Tiamat’s commitment to environmental responsibility in marine dredging is evident.

Here are nine ways in which Tiamat provides environmental advantages of marine dredging in ports and harbours:

1. Sustainable dredging
   Tiamat enables sustainable friendly dredging, alongside nature and for the benefit of nature. This new method of agitated dredging dilutes the sediment on the seabed and pumps it into the upper levels of the water column so it can be taken away by the tide or current, thus, “Dredging with Nature”.
2. Preserving marine eco-systems
   By using Tiamat, sediment is dredged from the seabed or riverbed in a non-invasive way. This encourages the natural movement of the sediment back into the water column. This natural suspension of sediment helps maintain a healthy and natural environment, whilst protecting sensitive marine ecosystems and habitats.
3. Supporting mud flat ecology
   Tiamat also supports the ecology of mud flats, as it replaces the need for invasive “beneficial placement” of sediment that could potentially disrupt wildlife in situ.
4. Preserving wildlife
   Wildlife and marine life in and around the dredging zone are less impacted because Tiamat encourages the sediment to disperse naturally and replenish the estuarian system rather than locating it somewhere else.
5. Enhancing water quality
   As Tiamat encourages natural re-suspension of sediment, there is no evidence of turbidity or water quality being impacted. A high-suspended sediment concentration plume forms immediately behind Tiamat, but it quickly disperses and does not impact the wider area.
6. Lowering fuel emissions and consumption
   By using Tiamat, vessels as small as 25 metres can carry out marine dredging, meaning lower fuel emissions compared with traditional methods. Similarly, because there is no need to transport sediment to and from a disposal site, Tiamat significantly lowers emissions into the environment. The ability to use a standard small workboat lowers fuel consumption compared to traditional methods. Tiamat’s greenhouse gas emissions are up to 90% lower than a comparable Trailing Suction Hopper Dredgers and would be even lower if the craft was powered by Hydrotreated Vegetable Oil biofuel.
7. Dredging with Nature
   By “Dredging with Nature”, Tiamat’s process of marine dredging can be completed in a manner that is kinder to nature and the marine environment.
8. Kind to the community
   Tiamat’s method of sustainable sediment dredging offers significant benefits to the local community, making it a more pleasant place to live, work, and visit. By eliminating the need to dispose of sediment at disposal sites, this method reduces noise and air pollution, creating a quieter and cleaner environment. It also decreases traffic on waterways, contributing to a safer and more serene atmosphere.Additionally, Tiamat’s approach promotes the natural movement of sediment back into the water column, which helps maintain healthy estuarine systems. This supports the ecology of mudflats, minimising disruptions to wildlife habitats that local communities depend on for ecological balance and economic activities such as fishing and tourism. Overall, this sustainable method not only enhances environmental health but also fosters a vibrant and thriving community.
9. Reducing noise and pollution
   Using Tiamat means less noise and pollution, as well as a reduction in traffic on waterways. The first study conducted into dredger noise in harbours, titled “Measurements of Tiamat and TSHD Noise Disturbance,” found that the Tiamat agitation dredger operates below safe levels for marine mammals and fish. According to the survey conducted by HR Wallingford, a leading specialist in noise and measurement modelling, Tiamat, is significantly quieter than a small Trailing Suction Hopper Dredger (TSHD).The noise level of Tiamat, when being pulled by a small workboat, measured around 170 decibels (dB), whereas the TSHD registered around 185 dB. The study highlights that “the measured sound pressure levels emitted from Tiamat (and workboat) are below levels associated with direct injury to marine mammals,” ensuring the safety of marine life. Fish are also unlikely to be harmed.

   This noise reduction contributes to a quieter and more peaceful environment for both marine life and local communities. Furthermore, by reducing greenhouse gas emissions by up to 67%, Tiamat supports cleaner dredging practices, promoting a healthier ecosystem. Also, Tiamat’s elimination of invasive sediment placement supports mudflat ecology, benefitting local ecosystems and communities. Trials at the Port of Felixstowe have demonstrated impressive efficiency and cost-effectiveness, with potential cost savings of up to 70% per dredging campaign.

If you have a dredging project that could benefit from Tiamat, contact us to discuss further.