Saving water in the green spaces: taking the city of Poitiers as an example

 

The city of Poitiers is a municipality in western central France. This metropolitan area was established in 1965, consisting of 13 communes. Greater Poitiers has 142,537 inhabitants and has been built around the principles of sustainable development of the environment and quality of life. Therefore, it has placed the saving on water in green spaces as its main concern.

Sports department of the City of Poitiers and the Greater Poitiers Metropolitan Area.

 

Greater Poitiers has 5 areas of activity, one of these being Gymnasiums, sports facilities and stadiums (GPS), 207 agencies (sports, technical and administrative branches of the French Public Sector), with the GPS hub consisting of 73 agencies and 78 sports installations, including 27 stadia equipped with an integrated irrigation system.

Personnel from this department work in all 12 of the communes in Greater Poitiers. On 1st January 2013 the metropolitan area will incorporate one more commune: Ligugé. The GPS hub will be responsible for the sports equipment that has been transferred: 1 sports complex including 2 gymnasiums, one stadium with one main pitch, 1 training ground, one playground and a second training arena. Poitiers will thus have 28 pitches equipped with automated sprinklers.

 

Sprinkling

The main playing areas (football and rugby) will be fitted with integrated sprinkling and they have benefited from improvements in the quality of the irrigation by adding sprinklers to the goal area or by rearranging the sprinklers.

An automated control system was set up in 2005, remotely controlled by computer. The water saved in the 2005 irrigation season compared with 2004 was 31,648 m3.

Prior to 2005, the integrated irrigation system was controlled by the different employees on the sites.  Now one employee is responsible for managing the irrigation of all the grass areas by attending to the irrigation frequencies and run times.

Prior to 2005, all the fields were sprinkler irrigated.

The decision was taken to restrict the quantity of irrigation water applied and make the turf “suffer slightly” in order to encourage the roots to grow deeper in search of moisture.

The aim was to strengthen the plant so as to ensure that it is more resistant when a legal decree to stop irrigation is issued.

 

Is automated irrigation alone enough to save on water?

 

The answer is no. It has to be able to estimate the exact amount of water that needs to be applied to the sports field so that the turf can be resistant and the playing surface meets the demands of the different sports played, either in training or during the matches and this relies on the skills of the users.

 

Probes and sensors

 

At the very beginning of the 2010 irrigation season, the company « Arc en Ciel » installed six WATERMARK MONITOR sensors on one of our main pitches.

The aim was to measure the hydrometric level of the soil so that we could monitor the quality and quantity of our irrigation of the natural grass sports fields.

The sports season is long and difficult for the turf: Overuse of the sports field in the course of the sporting season and too short intervals between periods of usage (matches stop in June and training starts again in July).

The recycling of water has been implemented with the recovery of water from the two large roofs and the water emptied from the Aquatic Centre, which allows for the 4 pitches to be irrigated on the site of the Michel Amand sports complex, without the need to use drinking water from the city mains supply.

This has resulted in financial savings and reduced water consumption.

The water from the roof of the Michel Amand sports complex could be used to irrigate the natural grass surfaces.

The water from the roof of the La Pépinière Aquatic Centre could be useful for supplying the sprinklers of the natural grass football pitches.  In fact, the Michel Amand sports complex and the La Pépinière Aquatic Centre both form a part of the site.

Finally, the installation of synthetic turfs as a replacement for natural grass pitches has reduced the irrigation requirements, resulting in:

Savings on water, electricity, paint used to mark the lines and labour.

A third synthetic grass pitch is planned for the Greater Poitiers Metropolitan Area with further investment to be made in several other sports complexes.