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?
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.
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
Recent Posts on RWQ
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 […]
10 tips to reduce your carbon footprint on dredging projects
The dredging industry uses a lot of energy and most of its requirements still depend on fossil fuels. Climate change requirements, increased energy costs and product demand are major factors pushing the dredging industry to adopt energy-efficient technologies and energy-saving techniques. Here are 10 tips to reduce your carbon footprint on dredging projects and take […]
Our consultants revel in developing and delivering unique and practical off-the-shelf tools that help improve their everyday work. We are constantly developing new functionality and creating new tools to improve our productivity. in2Dredging (i2D) is proud of its solid dredging toolbox and always enjoys presenting something new. The new Subsea Soil Stability tool assesses soil […]
After years of development, i2D is excited to finally present its new dredging estimating tool series called Estimator for (E4) Dredgers! Click here (https://www.in2dredging.com/dredging-tools/dredging-estimating-tool-series/) to have a look at what the future of dredging estimating looks like.
At this year’s PIANC APAC 2022 Conference in Melbourne, in2Dredging will present its extended abstract, entitled “Rock Dredging”. We look forward to meeting our coastal and maritime industry colleagues in person, hopefully without any significant COVID restrictions. With the abstract, our goal was to describe rock dredging in a nutshell with an interesting narrative. Although it […]
Perth, 16 August 2022 – The 14th of August 2022 marks the six-year business anniversary of in2Dredging Pty Ltd (i2D), an independent dredging consultancy backed by multi-disciplinary peers, cutting-edge academic knowledge, extensive field expertise, specialised off-the-shelf tools and an ISO certified management system. Six years on, the company has successfully completed close to 100 projects […]
Our Pumps ‘n Pipeline (PnP) users have often requested an intensive masterclass, so now is your chance! In three hours, you can learn to create your own suction and discharge production estimates or at the very least understand the physical limitations and associated risks of hydraulic transport. Professionals worldwide find our PnP tool easy to […]
These days, offline monitoring of dredging equipment can easily be done by acquiring the equipment’s digital data. The data can then be quickly visualised using in2Dredging’s Equipment Performance Review (EPR) and its new Proximity Tool. Regular monitoring by project stakeholders is key for the continued improvement of accurate and efficient operations. Monitoring Proximity Monitoring the […]
Last week I gave the presentation Dredging Fine Tailings at the two-day 2021 Mine Waste and Tailings Conference in Australia. Hosted by the Australasian Institute of Mining and Metallurgy (AusIMM), the online conference welcomed 340 delegates from around the world. in2Dredging was happy to participate in this technical conference that explored aspects of the waste […]
i2D Delivers the Dredging and Reclamation Masterclass
Friday 25 June was the last lesson of i2D’s first Dredging and Reclamation Masterclass 2021. How many times did we warn our students about the risks of various geotechnical and weather conditions! And how many times have we had the experience of major budget and schedule blowouts in our working careers simply because the challenges […]