Hydraulic modelling helps Nantes Métropole ensure a reliable supply for the city and surrounding municipalities

Nantes, a major city in western France, is the economic and cultural hub of the region. With over 650,000 inhabitants, Nantes Metropolis is the sixth-largest metropolitan area in France, comprising an intercommunality of 24 municipalities. Like many large cities, it faces the challenge of efficiently managing its water distribution network while accommodating a growing population. Maintaining reliable supply, ensuring accurate fire flow calculations and addressing environmental concerns are key priorities for Nantes Métropole as it works to optimise its system, which serves Nantes and surrounding areas. By implementing hydraulic modelling using DHI’s MIKE+, Nantes Métropole could now improve decision-making and address efficiencies in its water distribution network to meet current and future challenges by updating its drinking water master plan.

Challenge

Nantes Métropole’s challenges with its water distribution network were primarily related to infrastructure limitations and the growing demands of urban development and environmental sustainability. The existing hydraulic model was outdated and had not been updated to reflect changes in infrastructure. It also lacked comprehensive data on pipe diameters, limiting its accuracy and reliability. To address these challenges, Nantes Métropole is taking proactive steps to gain a detailed and reliable understanding of network performance, identifying peak demand locations including pressure zoning, sensitive points within the network and areas with potential for efficiency improvements. In addition, qualitative aspects such as ensuring water quality—residence time, contact time, chlorine levels and more—are also being closely monitored and optimised.

Solution

The teams from Nantes Métropole and DHI collaborated to develop a detailed hydraulic model of the water distribution network using MIKE+, which allows them to create a digital twin to simulate different scenarios and pinpoint vulnerabilities. 

The hydraulic model integrates disparate date sets into a unified representation of the water distribution network, considering factors like urban development, consumption patterns, physical infrastructure, regulatory compliance and future climate impacts. By reflecting both real-time conditions and future projections, the model becomes a powerful tool for strategic planning and improving efficiency. This approach is a clear improvement over traditional methods, which are often reactive and rely on outdated updates and forecasts, preventing them from fully addressing the complexity of modern water systems and changing conditions.

Results

The implementation of DHI's solution significantly benefitted Nantes Métropole, allowing the authority to:

• Accurately plan for future water demand based on various scenarios, including population growth and climate change impacts
• Enhance the overall efficiency and reliability of the water network, ensuring better service quality for residents and compliance with environmental regulations
• Improve water quality through better monitoring and control of key parameters
• Significantly reduce water loss and associated costs
  
  

The solution has equipped Nantes Métropole with the ability to manage water resources more efficiently, enabling data-driven decision-making and strategic planning to meet current and future challenges.