Solution

The original plan for the project in Hundested included ensuring that the hydraulic model was functioning optimally and simulated the hydrodynamic conditions correctly. At the same time, the sewer network needed a technical upgrade and climate-proofing to withstand more severe rain events (specifically increasing the design criteria to 33-year events).  

At the request of Halsnæs Utility's long-time external hydraulic engineering consultant, it was decided to issue a consultancy tender for an overall designplan for the project.  

It was decided that before replacing infrastructure, the hydraulic model needed to be calibrated and updated with resent data from the area. Because of the complexity of the system, it was decided to engage in a measurement campaign to ensure it accurately reflected the real-world dynamics in the area. The transition from strict model simulation to using downstream and later distributed sensor data to validate key parameters and performance would prove critical for both the project’s progress and its budget. 

When the first sensors were deployed, it quickly became apparent that the hydraulic model did not reflect reality. There was a significant discrepancy between the calculated values and the actual data.  

The issues were recognized, and it was proposed to expand the sensor deployment for a more comprehensive monitoring overview – assisted and delivered by Dryp. 

Dryp provided sensors to collect real-time data, enabling a comparison between the actual water levels and the model’s estimates. It became clear that the overflow volumes in Hundested were significantly smaller than predicted, revealing substantial inaccuracies in the hydraulic model. 

The Value Creation

The measurement campaign revealed that the original plans to expand the dimension of pipes and build large retention basins were far more extensive than necessary. Through the precise data collection from Dryp's sensors, it became possible to pin-point bottlenecks and gain a much clearer understanding of Hundested's sewer system, leading to significant cost savings. 

Key results included: 

The funds saved can now be reallocated to smarter solutions, such as preventing inflow and infiltration in critical sections. 

The Next Step

Halsnæs Utility now has a clear plan for the future in Hundested. Renovation and climate-proofing of the sewer network have just begun based on the new data. The master plan ensures that the utility has a precise understanding of how much the system must handle, allowing them to optimize the renovation efforts. In spring 2024, they will begin larger infrastructure projects in the town’s sewer system, particularly in the lower parts of the network where capacity must be ensured for future climate events. 

During the renovation Halsnæs Utility have obviously decided to keep a number of sensors to document the effects of improvements as they happen, and enable accurate updates of the hydraulic model for future operational use. 

The collaboration between Rambøll, who has been the main consultant for many years, Envidan, who assisted with the climate adaptation plan, and Dryp, who provided critical real-time data, has created a strong partnership. This four-party collaboration has ensured a productive relationship between consultants, hydraulic engineers, and data experts, which has been crucial to the project’s success. 

Halsnæs Utility is now ready to take the next step and begin the actual sewer renovation work across the entire town of Hundested, built on a solid, data-driven foundation.