The results are summarized in Table 1 in terms of classes of vulnerability to seepage along with the computed seepage probabilities, for 50 years’ return period. As can be seen, the proposed expeditious methodology allows to quickly analyze a large dataset identifying the levees characterized by the larger seepage probabilities, to properly address detailed controls and investigations. In this case, seven levees, shown in italic font in Table 1, are found to be prone to seepage. Overall, for all the flood durations, most of the investigated levees were characterized by a low vulnerability class (specifically, about 45%, 34%, and 25% for D equal to 12, 24, and 48 hours, respectively).
Table 1
Tiber River: class of vulnerability to seepage (and seepage probability) for the investigated levees for the /Hs ratio computed for a return period of 50 years (D= flood wave duration)
| Left side levee | Vulnerability class (seepage probability) | Right side levee | Vulnerability class (seepage probability) | ||||
|---|---|---|---|---|---|---|---|
| D = 12 hr | D = 24 hr | D = 48 hr | D = 12 hr | D = 24 hr | D = 48 hr | ||
| Tv1sx | overtopping | overtopping | overtopping | Tv1dx | high (0.60) | high (0.69) | high (0.74) |
| Tv2sx | overtopping | overtopping | overtopping | Tv2dx | overtopping | overtopping | overtopping |
| Tv3sx | low (0.04) | low (0.06) | low (0.09) | Tv3dx | overtopping | overtopping | overtopping |
| Tv4sx | mean (0.34) | mean (0.41) | mean(0.56) | Tv4dx | low (0.10) | low (0.16) | low (0.22) |
| Tv5sx | mean (0.34) | mean (0.43) | mean (0.58) | Tv5dx | overtopping | overtopping | overtopping |
| Tv6sx | overtopping | overtopping | overtopping | Tv6dx | overtopping | overtopping | overtopping |
| Tv7sx | overtopping | overtopping | overtopping | Tv7dx | low (0.24) | mean (0.33) | mean (0.38) |
| Tv8sx | low (0.03) | low (0.05) | low (0.07) | Tv8dx | low (0.01) | low (0.03) | low (0.05) |
| Tv9sx | low (0.01) | low (0.03) | low (0.04) | Tv9dx | overtopping | overtopping | overtopping |
| Tv10sx | low (0.01) | low (0.03) | low (0.05) | Tv10dx | mean (0.52) | high (0.66) | high (0.73) |
| Tv11sx | null | null | null | Tv11dx | overtopping | overtopping | overtopping |
| Tv12sx | mean (0.31) | mean (0.36) | mean (0.50) | Tv12dx | low (0.05) | low (0.09) | low (0.15) |
| Tv13sx | mean (0.42) | mean (0.56) | high (0.68) | Tv13dx | low (0.29) | mean (0.35) | mean (0.49) |
| Tv14sx | low (0.29) | mean (0.35) | mean (0.49) | Tv14dx | low (0.25) | mean (0.34) | mean (0.40) |
| Tv15sx | low (0.25) | mean (0.34) | mean (0.40) | Tv15dx | null | null | null |
| Tv16sx | low (0.22) | low (0.29) | mean (0.35) | Tv16dx | low (0.29) | mean (0.35) | mean (0.49) |
| Tv17sx | low (0.05) | low (0.07) | low (0.11) | Tv17dx | low (0.14) | low (0.21) | low (0.26) |
| Tv18sx | low (0.19) | low (0.23) | mean (0.30) | Tv18dx | low (0.11) | low (0.20) | low (0.24) |
| Tv19sx | low (0.22) | low (0.29) | mean (0.35) | Tv19dx | low (0.21) | low (0.25) | mean (0.34) |
| Tv20sx | low (0.14) | low(0.21) | low (0.26) | Tv20dx | low (0.22) | low (0.29) | mean (0.35) |
| Tv21sx | low (0.08) | low (0.14) | low (0.21) | Tv21dx | low (0.21) | low (0.26) | mean (0.34) |
| Tv22sx | null | null | null | Tv22dx | low (0.26) | mean (0.34) | mean (0.42) |
| Tv23sx | overtopping | overtopping | overtopping | Tv23dx | low (0.15) | low (0.22) | low (0.28) |
| Tv24sx | null | null | null | Tv24dx | low (0.12) | low (0.20) | low (0.24) |
| Tv25sx | null | null | null | Tv25dx | null | null | null |
| Tv26sx | null | null | null | Tv26dx | null | null | null |
| Tv27sx | null | null | null | Tv27dx | null | null | null |
| Tv28sx | null | null | null | Tv28dx | null | null | null |
| Tv29sx | mean (0.55) | high (0.68) | high (0.74) | Tv29dx | low (0.29) | mean (0.35) | mean (0.49) |
| Tv30sx | null | null | null | Tv30dx | mean (0.49) | high (0.64) | high (0.72) |
| Tv31sx | null | null | null | Tv31dx | low (0.08) | low (0.12) | low (0.20) |
| Tv32sx | null | null | null | Tv32dx | mean (0.36) | mean (0.49) | high (0.63) |
| Tv33sx | low (0.06) | low (0.09) | low (0.15) | Tv33dx | low (0.10) | low (0.20) | low (0.23) |
| Tv34dx | mean (0.41) | mean (0.56) | high (0.67) | ||||
| Left side levee | Vulnerability class (seepage probability) | Right side levee | Vulnerability class (seepage probability) | ||||
|---|---|---|---|---|---|---|---|
| D = 12 hr | D = 24 hr | D = 48 hr | D = 12 hr | D = 24 hr | D = 48 hr | ||
| Tv1sx | overtopping | overtopping | overtopping | Tv1dx | high (0.60) | high (0.69) | high (0.74) |
| Tv2sx | overtopping | overtopping | overtopping | Tv2dx | overtopping | overtopping | overtopping |
| Tv3sx | low (0.04) | low (0.06) | low (0.09) | Tv3dx | overtopping | overtopping | overtopping |
| Tv4sx | mean (0.34) | mean (0.41) | mean(0.56) | Tv4dx | low (0.10) | low (0.16) | low (0.22) |
| Tv5sx | mean (0.34) | mean (0.43) | mean (0.58) | Tv5dx | overtopping | overtopping | overtopping |
| Tv6sx | overtopping | overtopping | overtopping | Tv6dx | overtopping | overtopping | overtopping |
| Tv7sx | overtopping | overtopping | overtopping | Tv7dx | low (0.24) | mean (0.33) | mean (0.38) |
| Tv8sx | low (0.03) | low (0.05) | low (0.07) | Tv8dx | low (0.01) | low (0.03) | low (0.05) |
| Tv9sx | low (0.01) | low (0.03) | low (0.04) | Tv9dx | overtopping | overtopping | overtopping |
| Tv10sx | low (0.01) | low (0.03) | low (0.05) | Tv10dx | mean (0.52) | high (0.66) | high (0.73) |
| Tv11sx | null | null | null | Tv11dx | overtopping | overtopping | overtopping |
| Tv12sx | mean (0.31) | mean (0.36) | mean (0.50) | Tv12dx | low (0.05) | low (0.09) | low (0.15) |
| Tv13sx | mean (0.42) | mean (0.56) | high (0.68) | Tv13dx | low (0.29) | mean (0.35) | mean (0.49) |
| Tv14sx | low (0.29) | mean (0.35) | mean (0.49) | Tv14dx | low (0.25) | mean (0.34) | mean (0.40) |
| Tv15sx | low (0.25) | mean (0.34) | mean (0.40) | Tv15dx | null | null | null |
| Tv16sx | low (0.22) | low (0.29) | mean (0.35) | Tv16dx | low (0.29) | mean (0.35) | mean (0.49) |
| Tv17sx | low (0.05) | low (0.07) | low (0.11) | Tv17dx | low (0.14) | low (0.21) | low (0.26) |
| Tv18sx | low (0.19) | low (0.23) | mean (0.30) | Tv18dx | low (0.11) | low (0.20) | low (0.24) |
| Tv19sx | low (0.22) | low (0.29) | mean (0.35) | Tv19dx | low (0.21) | low (0.25) | mean (0.34) |
| Tv20sx | low (0.14) | low(0.21) | low (0.26) | Tv20dx | low (0.22) | low (0.29) | mean (0.35) |
| Tv21sx | low (0.08) | low (0.14) | low (0.21) | Tv21dx | low (0.21) | low (0.26) | mean (0.34) |
| Tv22sx | null | null | null | Tv22dx | low (0.26) | mean (0.34) | mean (0.42) |
| Tv23sx | overtopping | overtopping | overtopping | Tv23dx | low (0.15) | low (0.22) | low (0.28) |
| Tv24sx | null | null | null | Tv24dx | low (0.12) | low (0.20) | low (0.24) |
| Tv25sx | null | null | null | Tv25dx | null | null | null |
| Tv26sx | null | null | null | Tv26dx | null | null | null |
| Tv27sx | null | null | null | Tv27dx | null | null | null |
| Tv28sx | null | null | null | Tv28dx | null | null | null |
| Tv29sx | mean (0.55) | high (0.68) | high (0.74) | Tv29dx | low (0.29) | mean (0.35) | mean (0.49) |
| Tv30sx | null | null | null | Tv30dx | mean (0.49) | high (0.64) | high (0.72) |
| Tv31sx | null | null | null | Tv31dx | low (0.08) | low (0.12) | low (0.20) |
| Tv32sx | null | null | null | Tv32dx | mean (0.36) | mean (0.49) | high (0.63) |
| Tv33sx | low (0.06) | low (0.09) | low (0.15) | Tv33dx | low (0.10) | low (0.20) | low (0.23) |
| Tv34dx | mean (0.41) | mean (0.56) | high (0.67) | ||||
The levees affected by failure during the severe flood of November 2005 are in bold font.