4.4.2. The Short-Term Erosion Index IR

Short-term erosion indexes IR2019, IR2020, and IR2021 were evaluated for both test areas (Petacciato beach, profiles P1–P7, and Campomarino beach, profiles C1–C5, Table 9) on the basis of R and R/L values obtained for both normal wave conditions (Hs = 0.7 m) and average extreme wave conditions (Ht = 3.5 m).

With regard to normal wave conditions, the results obtained for test area A highlight the persistence of low short-term erosion indexes (IR values of 1, Table 9), with the only exception of the IR2021 values for profiles P1 and P2, which increased to 4 and 2, respectively. However, regarding average extreme wave conditions, the profiles showed a notable variation in IR values that oscillated between 1 and 4, but without showing any clear trend from 2019 to 2021.

The results obtained for test area B for normal wave conditions indicate a major variability of the short-term erosion indexes, which oscillated between values of 1 and 4, showing an overall worsening of erosion conditions from 2019 to 2021. The only exception is profile C3, which maintained an IR value of 1, thus confirming the important role played by human interventions that have annually affected this portion of the beach. Concerning average extreme wave conditions, the IR values reached maximum values of 4 for all profiles, with the only exception of C3, which is characterized by IR values of 2 in 2019 and 3 in the following years, 2020 and 2021 (Table 9).
