PSI - Issue 78

Marco Faggella et al. / Procedia Structural Integrity 78 (2026) 2141–2146

2143

compliant action PGA: A) the Spillway 1 Operation Station B) the Electric Generator Box; C) the Management Building and D) the Intake Tower Access Footbridge. Vulnerability of these facilities can be summarized as a 40% of SLV PGA (0.4 x 0.239g ≈ 0.1 g), and 30% SLC PGA for the Fontanelle bridge (0.3 x 0.3215g ≈ 0.1 g PGA).

4. Regulation and Drought induced Storage Loss The drought-induced water loss risk can be mounted on the same seismic PSHA plot, provided that a Poisson model applies also to the likelihood of reservoir depletion. We make this assumption based on the probabilistic yield effectiveness presented by Cimorelli et al. (2021). This work describes the Camastra water supply falling below an operational threshold with a return period in the range of 3 to 6 years and a Poisson exponential decay of reliability as a function of years-to-failure. For the drought scenario, we use the 5-year return period based on the Camastra study by Claps et al. (1998). This value of return period corresponds to a 20% annual probability of failure, and, as discussed above, at limited values of operating storage as low as 9Mmc with predicted yield of about 35mmc, as per the probabilistic curves of possibility of derivation, not only it minimizes (Lower Bound) the likelihood of failure in achieving a target draft, (Basson et al. 1994, Basson et al. 2001), but it also captures the scenario of total depletion and failure to achieve annual recharge (ITCOLD 2016, B. Molino Camastra report). This is estimated considering that the Dam was designed for drinking use demand corresponding to 22,3Mmc/year, minimum ecological outflow 31,5Mmc/year, total 53,8Mmc/year, (Claps et al. 1998), and that additional reliance on natural springs contributions became very scarce during the 2024 drought.

(a)

(b)

Fig.1. Camastra Dam, (a) embankment cross section, (b) dam and sub-facilities during 2024 water storage failure.