The combined sewage network running from the center of Marseille to the Cortiou outfall is a key asset in the sanitation system global management. During rain events, the rain water flows increase significantly the existing waste water flows transferred to the waste water treatment plant, reaching volumes that the Geolide can no longer handle since its maximum daily treatment capacity is limited to 325,500 m³.
Global warming increases the number of violent Mediterranean rainfall events.
Since it is impossible to install facilities so designed as to collect and process the water flowrates resulting from exceptional rainfall events, it is essential to provide efficient means that make it possible to forecast and manage torrential flows in rivers, runoffs on impervious grounds and the subsequent floods, since they are a threat to the population, the urban assets and the coast health.
Marseille must be protected from floods
Whenever a rain storm is feared, SERAMM manages it by means of its real-time rainfall dynamic management system driven from its control-monitoring center called "le Ph@re". Constantly improved with new technologies, the SERAMM control-monitoring system makes it possible to forecast the potential rain water volumes that will fall on the city or on part of the territory, to modelise the circulation of the flows and to direct the latter to the networks in order to optimise the storage capacities of the 36 retention basins and to prevent the facilities from being saturated.
HOW DOES IT WORK?Aquadvanced: real-time device comprised of 3 modules
Anticipation
Weather forecasts enable managing the rainfall events, their intensity and their duration.
Modelling
The expected rainfall quantity is converted into flowrates in the networks in order to optimise the waste water treatment plant performance and to anticipate the risk of scattered runoffs to the sea.
Control-Monitoring
A control-monitoring cockpit of the works triggers the necessary actions.
WORKS AND FACILITIES TO MINIMISE THE IMPACT OF
RAINFALL EVENTS IN THE TERRITORY, ON THE BEACHES AND
ON THE CALANQUES NATIONAL PARK
The Ganay basin, a concrete cathedral to store the excess waster water and rain water
On the basis of past rainfall events it has been decided to build the 50,000m³ Ganay retention basin designed to store temporarily the excess water retained before it is being treated in the WWTP, and to prevent the discharge at sea of 1 million cubic meter of untreated water per year. Fifty million euros have been invested to achieve this facility integrated within the Ph@re "technological" control-monitoring.
On the basis of past rainfall events it has been decided to build the 50,000m³ Ganay retention basin designed to store temporarily the excess water retained before it is being treated in the WWTP, and to prevent the discharge at sea of 1 million cubic meter of untreated water per year. Fifty million euros have been invested to achieve this facility integrated within the Ph@re "technological" control-monitoring.
m³ of water not discharged to the sea.
HOW DOES IT WORK?Zooming in on the operation
of the retention basin.
of the retention basin.
The Huveaune weir gate designed to protect beaches
from river-borne pollutions.
SERAMM manages the weir gate installed on the Huveaune river to fine tune the water flows and screen the waste. This infrastructure diverts up to 30m³/s of rain water to the Cortiou calanque and thus protects the beaches. Following violent rainstorms, the weir gate is lowered to protect the city from floods. Thus the Huveaune returns to its natural course and entrains the endemic pollution and the floating waste which end up on the beaches leading to bathing prohibition.
from river-borne pollutions.
SERAMM manages the weir gate installed on the Huveaune river to fine tune the water flows and screen the waste. This infrastructure diverts up to 30m³/s of rain water to the Cortiou calanque and thus protects the beaches. Following violent rainstorms, the weir gate is lowered to protect the city from floods. Thus the Huveaune returns to its natural course and entrains the endemic pollution and the floating waste which end up on the beaches leading to bathing prohibition.
HOW DOES IT WORK?Zooming in on the Huveaune endemic pollutions
Rainfall water,
what consequences for our beaches?
opening rate of the Marseille beach during the summer season.
During rainfalls, the rain water runoffs end up in the sea and entrain polluting elements. SERAMM has increased its analysis tools to assess the quality of the bathing water and to alert the collectivities to aid in the decision making process concerning the opening and access to the beaches.
Causes for beach closing
- 82%Rainfall events
- 12%Street cleanliness
- 4%Unknown causes
- 2%Network operation
