Premium
Failure Probability Analysis of Levees Affected by Mammal Bioerosion
Author(s) -
Balistrocchi Matteo,
Moretti Giovanni,
Ranzi Roberto,
Orlandini Stefano
Publication year - 2021
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2021wr030559
Subject(s) - levee , flood myth , environmental science , flow (mathematics) , geotechnical engineering , geology , hydrology (agriculture) , geography , mechanics , physics , archaeology
Mammal bioerosion is an emergent threat to the functionality of levees. In the present paper, the problem of assessing the failure probability of levees affected by mammal bioerosion is addressed. A fully bivariate description of peak flow discharge and flood duration is combined with a deterministic unsteady seepage flow model to obtain a suitable model of variably disturbed levee response to the observed natural variability of floods. Monte Carlo analysis is also implemented to evaluate the epistemic uncertainty connected to the description of the river system. The obtained model is tested with respect to a real‐world levee located along the Secchia River in northern Italy, which underwent a disastrous failure caused by mammal bioerosion in 2014. The convex linear combination of two Archimedean copulas is found to fit the empirical dependence structure between peak flow discharge and flood duration. The reliability of the unsteady seepage flow model is tested against detailed numerical simulations of the seepage occurring through the levee body. A limit state function is obtained by comparing the maximum extent of the seepage front to the distance between the den end and the riverside levee slope, and the corresponding levee safety and failure regions are delimited. Results obtained from the developed model reveal a significant impact of mammal dens located near the levee crest in terms of failure probability and related return period. This impact is consistent with failures observed in the study area.