BlueCan: cutting carbon emissions by improving the water quality of lakes and ponds

BlueCan is a tool that allows water management authorities to assess carbon emissions from ponds and lakes. The tool shows how different measures can improve water quality and reduce carbon emissions. BlueCan is a joint project involving Witteveen+Bos and Deltares.

Carbon emissions from ponds and lakes higher than expected

The first step was a project at Witteveen+Bos that measured the capture of carbon by surface water. In addition, a study by the Radboud University of greenhouse gas emissions from ditches and urban ponds showed that those emissions were much higher than previously assumed. Sacha de Rijk, Deltares project leader: “That study showed that local ponds generate the same level of emissions as 200,000 cars. At that point, of course, it really made sense to produce a tool that can estimate emissions but, above all, that can show immediately what actions you can take.”

Combination of water quality models: the best of two worlds

BlueCan does exactly that: it assesses emissions and shows which measures have an effect. The tool is based on a combination of two existing water quality models, PCLake and DELWAQ (water quality engine of Delft3D FM Suite). The strengths of both models were carefully integrated and the necessary adaptations were made. In addition, a metamodel has been created that allows water managers to estimate the annual emissions of fresh water on the basis of a number of system characteristics. To make the tool more reliable, the BlueCan project teamed up with water management authorities to measure a number of parameters in the field and in the lab.

Specific measures

One of the specific measures that can be assessed with the tool is the reduction of nutrient levels. For example, you can simulate how carbon emissions are positively affected by a reduction in the phosphate load. Sliding a bar on the screen shows how emissions increase or decrease. You can then decide, for example, not to start dredging or to reduce the phosphate load in another way.

Extra contribution to climate ambitions by means of clean water

BlueCan shows an important link between water quality and greenhouse gas emissions. A turbid, algae-rich system produces a lot more emissions than a clear, plant-rich system. Indicative calculations show that the difference in emissions can be a factor of 10. The link between water quality and emissions results in a win-win situation. By working to keep water clean and enhance biodiversity (by implementing WFD measures), we can work directly on achieving our climate ambitions. In this way, investments in water quality make a significant contribution to the necessary reduction of greenhouse gas emissions.

Further development

The first version of the BlueCan tool is a QuickScan. It will allow water managers to estimate greenhouse gas emissions and to work out how to cut those emissions. In collaboration with the water management authorities, BlueCan will be further developed incorporating feedback from the field. Also, a handbook will be produced with information about the carbon processes and the link with eutrophication, how to use the tool, a step-by-step analysis, the role of sediment, and measures to reduce emissions.

Would you like to know how BlueCan can help your organisation to cut carbon emissions? Are you interested in working with Deltares and Witteveen+Bos on developing this tool further on the basis of your specific questions?

For more information, contact Sacha de Rijk, project leader and water quality expert.

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