Protecting Water Quality through an Urban Forest
Greater Lyon, France, France
Eau du Grand Lyon, Veolia’s fully owned subsidiary, provides and distributes drinking water in the Grand Lyon area. The region—established in 2015 to improve integrated planning and services throughout the metropolis—comprises 59 municipalities with a population of 1.3 million. Veolia is a French multinational that provides strategies related to water, wastewater, energy, and waste management, with a particular focus on promoting the transition towards a circular economy. The first contract won by the Compagnie Générale des Eaux, Veolia’s ancestor, was with the city of Lyon, to which it has been providing water services without interruption since 1853. On behalf of Grand Lyon municipality, the operator is protecting 375 hectares around water well fields in the heart of the city. It has found this to be more cost-effective than a more complex water filtration plant— and it generates significant biodiversity benefits.
Challenges
Eau du Grand Lyon was created in February 2015 when Veolia signed an eight-year contract with Grand Lyon for a larger geographical area than previous contracts covered. Grand Lyon metropolis owns the land and the water infrastructure assets; it also decides on the investment programme and sets water tariffs. Day-to-day operations and maintenance are outsourced to Eau du Grand Lyon.
Water for the Grand Lyon area comes mainly from wells in the Rhone River alluvial aquifer in the heart of the city, through river bank filtration and managed aquifer recharge (peak production 450,000 cubic metres per day from 112 wells). Protecting water at the source is paramount to avoid the need for an expensive filtration plant and to prevent accidental pollution. The objective is to conserve the natural recharge area (a forest), which is also valuable local biodiversity.
Financing
Veolia assessed benefits generated from this natural infrastructure by modelling the avoided production costs when compared to a theoretical grey infrastructure that would deliver similar water production capacity (1 million m3/ day). It found that total annualized costs associated with a typical coagulation and filtration plant would be in the range of Euros 52 to 74 million per year, as opposed to the annualized costs of the existing green infrastructure (Euros 32 million per year). Significant savings are achieved on operating costs, which stand at Euro 0.04 per m3 for green infrastructure (wellfields and source protection) as opposed to Euros 0.15 to 0.25 per m3 for a typical plant. This assessment confirmed that, in this case, source protection is likely to be more cost-effective than grey infrastructure. Managing the natural infrastructure enables the operator to keep water tariffs down through cost savings.
Actions & impacts:
Eau du Grand Lyon created artificial recharge ponds as a pollution barrier, and it has entrusted a reforestation and conservation program to the National Office of Forests to protect the natural recharge area for the well fields. Biodiversity monitoring and invasive species control actions are in place. Introducing these NbS for source water protection led to water being 100 percent compliant. These actions also created a natural habitat reserve at the heart of the metropolis, hosting 32 percent of the flora of Greater Lyon (including 24 orchid species) and sensitive heritage species such as wildcats, beavers, and otters. The area is also a migration corridor and a reproduction site for birds. Economic benefits also resulted from these actions, by increasing the attractiveness of the nearby area and generating green jobs; five wardens work at the site.
References
Veolia. (2014). Press release: Veolia Water contracted by Greater Lyon to manage its water distribution service for eight years.
Veolia website: https://www.veolia.com/en
Presentation by Boris David (Veolia Water) at 16th January 2019 London workshop Nature Based Solutions for Water Resources Management, organized by TNC
©Jason Houston
