Return Water Quality (RWQ) Tool

The Return Water Quality (RWQ) Tool from in2Dredging (i2D) predicts the quality of return water, i.e. the amount of sediment contained in the water flowing out of a given reclamation area.

When dredged material is pumped into a reclamation area, the sediment and water mixture flows over the reclamation area and possibly through one or more settling basins. During this process, the material settles and the excess water or return water is drained via one or more outlet into the receiving water body. Depending on the type of dredged material and the dimensions of the reclamation area (and settling basin), the return water might contain suspended particles when returning to the surface water.

A question that often comes up is: Will our reclamation area have enough capacity to hold the amount of dredged material, considering factors such as bulking and rock or particle degradation? Furthermore, are settling basin(s) needed and if yes, how large do they need to be in order to let the fine particles settle and to return clear water or water not exceeding the environmental water quality requirements?

Port Brisbane reclamation area sand fill and sedimentation basin area return water quality
Port Brisbane reclamation area and sedimentation basin

The RWQ model generates a particle size distribution and follows the settlement of each particle size along the length of the sand fill (reclamation area) and/or sedimentation (settling) basin. The model provides the concentration and particle sizes still suspended in the return water. The width, length, depth of fill/and or basin can be optimised to improve sedimentation and return water quality.

When the discharge rate and mixture properties are provided or estimated, RWQ can predict the quality of the return water. The tool was initially built for a specific project and has been developed, fine-tuned and validated ever since. Field measurements have driven the development of the design tool. Only a limited amount of literature on sedimentation and erosion processes was utilised to maintain its suitability for a practical design application. This approach has led to a tool that supports dredging engineers when designing an optimal reclamation area and sedimentation basin(s). The more complex Computation Fluid Dynamic modelling is often unrealistic and impractical as a design tool.

Many projects have shown that the definition of the input parameters drives the accuracy of the predictions. An especially high definition of the fines (the proportion of material smaller than 63 micrometres) is key to providing an accurate prediction. The highest practically achievable fine content definition leads to g/l or kg/m3, which can be linked through analysis of water samples, correlation and extrapolation, to turbidity, and therefore environmental regulations. i2D use rules of thumb and experience to ensure that the return water quality is compliant with the allowed turbidity levels.

Potential Uses

  • Designing reclamation areas and sedimentation basins
  • Predicting return water quality
  • Comparing the amount of suspended solids in return water with allowed turbidity levels
  • Providing insight into particle segregation on reclamation areas
  • Determining the ideal discharge rate and mixture density to improve sedimentation rates
return water quality rwq results sedimentation reclamation fill area

Recent Posts on RWQ

Advance Your Career with i2D’s Dredging & Reclamation Masterclass

Join in2Dredging’s intensive Dredging & Reclamation (D&R) Masterclass and master the fundamentals of successful dredging and reclamation projects. Whether you are just starting your career or looking to refine your expertise, the D&R Masterclass is for you. Why Join the Dredging & Reclamation Masterclass? This Masterclass is tailored for professionals seeking to enhance their expertise […]

Successful Water Injection Dredging Trials at the Port of Melbourne

We are excited to announce the successful completion of Water Injection Dredging (WID) trials at the Port of Melbourne. The trials were conducted under the expert supervision of in2Dredging Pty Ltd (i2D) and were executed by the contractor, Polaris Marine Group. The Water Injection Dredging Solution This innovative approach harnesses the power of gravity to […]

Valerie Biernaux Rejoins in2Dredging as Lead Dredging Engineer

We are excited to announce that Valerie Biernaux has rejoined in2Dredging (i2D) as Lead Dredging Engineer, further strengthening our growing market presence in Europe. Based in Belgium, Valerie’s return marks a significant milestone for our company as we expand our reach across the region. In addition to our developing presence in Dutch-speaking regions, Valerie’s fluency […]

Pumps ‘n Pipeline Masterclass Unlocks Your Dredging Potential!

Are you a dredging engineer looking to enhance your skills and boost productivity in your daily work? in2Dredging (i2D) designed the Pumps ‘n Pipeline (PnP) Masterclass specifically for professionals like you wanting to deepen their understanding of hydraulic transport systems. Pumps ‘n Pipeline Masterclass Content Over the course of two intensive 2-hour sessions (totalling 4 […]

i2D to Present at PIANC 2024 in Sydney, Australia

in2Dredging Pty Ltd (i2D) is presenting at the PIANC APAC Conference again this year, which takes place from August 27 to 30, 2024, in Sydney. This event will bring together a great group of engineers, planners, scientists and contractors. It will focus on technical, operational and other issues related to Asia Pacific’s ports, harbours and […]

i2D Presents the Dredging & Reclamation Masterclass in Singapore

Mark your calendars for the upcoming Dredging & Reclamation Masterclass to be held on May 15th to 17th 2024 in Singapore. In just 3 days, you will enhance your expertise in dredging and reclamation project planning and execution, with a guaranteed return on investment for both time and resources.  Our masterclass provides comprehensive coverage of […]

Join Our PnP Masterclass!

Are you a passionate dredging or mining industry professional seeking to enhance your estimating skills and gain realistic productivity expectations for hydraulic transport of soil-like materials? Look no further! Our upcoming PnP Masterclass Program is tailored just for you. What to Expect Learn from Simon Burgmans, a seasoned professional with over 20 years’ experience in […]

i2D Presents its Drilling & Blasting Masterclass

Due to overwhelming demand in2Dredging’s (i2D) is offering a Drilling & Blasting (D&B) Masterclass.  Dive into the world of marine D&B and learn how to estimate progress and understand the activities involved! Why Attend Join us for a training course on the fundamentals of marine D&B, presented by i2D’s principal dredging consultants Greg Miller and […]

Pumps ‘n Pipeline v1.7 is Here!

A new enhanced version of Pumps ‘n Pipeline (PnP) is here.  We have listened to your feedback and included an array of requested enhancements to Pumps ‘n Pipeline v1.7. What is Pumps ‘n Pipeline? For those new to Pumps ‘n Pipeline, PnP is a suction and discharge production estimation tool.  This analytical tool can be […]

14th Dredging & Land Reclamation World Summit

Singapore will be hosting this year’s Dredging & Land Reclamation World Summit from 5 to 8 September, and Simon Burgmans, Director & Principal Dredging Consultant at in2Dredging Pty Ltd (i2D), will be giving two workshops and three presentations. During these sessions Simon will share his expertise in cost-effective and successful dredging as well as land […]