Natural-based solution to mitigate flood risk due to SAND BOILS reactivations along the Po River (LIFE SandBoil)

Description:

The occurrence of sand boils on river embankments during high water events is a common sign of backward erosion piping (BEP), an internal erosion process caused by seepage into the sandy aquifer beneath a river embankment. The resulting upward seepage pressures lead locally to sand fluidisation as if the sand is boiling. The ejection of sand grains mixed with water from the exit hole is considered to be the onset of erosion, which may progress in the upstream direction and give rise to shallow pipes in the sandy aquifer. The eroded sand particles usually form a ring around the fluidised zone, like a volcano crater. The progression and widening of the pipes may result in a collapse of the riverbank, with catastrophic consequences. The activation or reactivation of a sand boil is triggered by high water events, such as flooding that has become more common and intense, and longer lasting in recent decades due to climate change. The risk of riverbank instability, including failure mechanisms triggered by BEP, is thus growing. 

The main objective of the LIFE SandBoil project is to mitigate the risk of BEP by means of an innovative, sustainable, natural-based and cost-effective engineering solution. The intervention is devised to stop the progression of piping beneath the riverbank, which might lead to severe erosion and to the collapse of the structure. Reducing the risk of a riverbank collapsing also decreases the risk of flooding. The project aims to scale up the prototype by demonstrating the technology along a segment of a riverbank. A long-term goal is to apply the intervention to the 130 catalogued Po river segments affected by sand boils. The technology will also be replicated in Hungary along the Danube river. The project actions aim to promote safer land use with a strong socio-economic impact; costly emergency management and restorations will be avoided. A further objective is to produce guidelines for the design of an effective and sustainable engineering solution to mitigate the flood risk from BEP worldwide.

Project information

Lead

ALMA MATER STUDIORUM - Università di Bologna - Dipartimento di Ingegneria civile, chimica, ambientale e dei Materiali - DICAM, Italy

Partners

ÉDUVIZIG (North-Transdanubian Water Directorate Észak-dunántúli Vízügyi Igazgatóság), Hungary
AIPO (Agenzia Interregionale per il fiume Po), Italy
OMI (Officine Maccaferri Italia S.r.l.), Italy

Source of funding

LIFE