SMIVAL Rapport d'activité 2009 (Activity report 2009)

The SMIVAL (Syndicat Mixte Interdépartemental de la Vallée de la Lèze - an association of 24 communes localised in the Lèze's valley) has been created in 2003. It is responsible for leading, for defining and for implementing actions for a qualitative and quantitative use of the Lèze and its tributaries and for preventing its floods. For preventing floods, an actions programme (called PAPI) has been set up. One action refers to the plantation of floodbreaking hedgerows in order to slow down the flood peak.
Hedgerows are located across the flooding plain of the river and they are regularly spaced every 300 to 500 metres. Partially obstructing the flow, hedges can slow running water to dissipate the force and reduce the impacts of flooding. This is a cumulative effect that is measured across the entire valley, with a significant decrease in rates. According to thre PAPI, 75 km of floodbreaking hedgerows were initially planned to be planted until 2016.