Joint Research Activity: Hydrodynamic design of stormwater retention ponds
Partners involved
About the project
The retention pond of Aalborg is a pilot facility monitored by AAU team where stormwater drained from a small residential area catchment is stored before being pumped into a natural pond.
The goal of this project, developed in the second half of 2023 by 3 Co-UDlabs partners as part of the Joint Research Activities, was to analyse and optimize the removal of sediments and pollutants by deposition during the retention of the stormwater in order to improve the performing and design of this kind of solution in future applications. This will help to develop the understanding of hydrodynamics for improving the treatment of runoff water, allowing for stormwater retention ponds to be designed, or existing ponds modified, to maximise their potential for water purification.
Data necessary for the design approach were generated by applying large scale particle image velocimetry (PIV) technology on a stormwater retention pond in Denmark alongside other sensors to measure water levels at the inlet, within the basin, as well as the flow through the facility. The main objective was to install cameras and perform surface velocity measurements in the retention pond in order to obtain useful data to calibrate a Computational Fluid Dynamics model and optimize the operation of the installation.
Main findings
- During experiments it was possible to measure the sediment loads and total suspended solids (TSS) from 2 rainfall events to see how first flush affects the connected catchment.
- Through the experiments it was found that sawdust and wheat could be used as plastic substitute particles to avoid pollution of the site, which improved the detection significantly when compared to not adding any particles.
- This joint work will lead to optimize the performance of the facility favouring sediment deposition and reducing the resuspension of particles when emptying, thus reducing the cost of maintaining the pond. This, with the detailed work carried out by AaU on the hydraulic behaviour of the retention pond and on the sediment characterization in terms of its particle size distribution, organic matter content and presence of heavy metals, will contribute to increase the knowledge about the performance of this kind of stormwater treatment solutions.
Successful outcomes:
- The partners involved enjoyed working with each other and all parties got relevant results and benefitted from the partnership: Aalborg have gained a lot of PIV experience and they are interested in continuing using this technique in the future and also to use it in the laboratory for other kinds of experiments; UDC gained more experience in the practical applications of the technology and how can it be deployed outside of the laboratory.
- The involved project partners are considering future projects on this topic, with potential additional industry partners.
- Once the research is completed, implementation of the results will be spread to the asset owners and communicating the design strategy on a national and international level.
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