## 3 Results
### Average Wave Overtopping Discharge
Here, the reservoir is considered as an artificial promenade, and, according to [60], \(\gamma_{\text{prom}}\) is derived as a function of \(\Delta\mathsf{B}_{\text{rs}}/\text{L}_{\text{m}-1,0}\) and of \(\gamma_{\text{v}}\), as follows:  
\[\gamma_{\text{prom}}=0.87\cdot(1-0.47\cdot\Delta\mathsf{B}_{\text{rs}}/\text{ L}_{\text{m},0})\cdot\gamma_{\text{v}} \tag{16}\]  
Equation (16) is valid for \(0.04<\Delta\mathsf{B}_{\text{rs}}/\text{L}_{\text{m}-1,0}<0.40\), \(0.17<\mathsf{h}_{\text{wall}}/\text{R}_{\text{c}}<0.80\) and \(0.25<\lambda<0.38\). The latter condition restricts the range of the experimental data to be used to test the reliability of Equation (16). More recently, [PERSON] et al. [41] investigated the overtopping behavior of the physical model of OBREC with a nose on the top of the vertical wall. In this case, the nose dimensions were fixed, with \(\lambda=0.10\). An empirical relation to predict \(\mathsf{q}_{\text{rear}}\) was suggested:  
\[\mathsf{q}_{\text{rear}}\cdot\mathsf{T}_{\text{m}-1,0}/\text{L}_{\text{m}-1, 0}{}^{2}=0.0139\cdot\exp(-7.17\cdot\mathsf{X}_{\text{rear}}) \tag{17}\]  
where the OBREC geometrical parameters were grouped into the dimensionless factor \(\mathsf{X}_{\text{rear}}=(\text{R}_{\text{c}}/\text{H}_{\text{m}0})\cdot( \Delta\mathsf{B}_{\text{rs}}/\text{B}_{\text{r}})^{0.5}\cdot(\Delta\mathsf{R }_{\text{c}}/\text{d}_{\text{w}})^{0.25}\). Note that Equation (17) allowed us to predict the observed overtopping discharges in OBREC with good accuracy (NSE = 0.96). However, the nose size was not considered to be an influential parameter. Figure 10 shows the comparison between measured overtopping discharges and corresponding predictions by applying Equations (11), (15) and (17). Figure 10 shows that the observations are not sufficiently estimated by the relation proposed by [30] for structures with a storm wall and a nose. The curve of Equation (11) mainly underestimates the measurements for all the nose dimensions. In particular, the largest discrepancy is derived for about \([(\text{R}_{\text{c}}/\text{H}_{\text{m}0})/(\gamma_{\text{v}}\cdot\gamma_{ \text{par}}\cdot\gamma_{\text{s0,par}})]<2.50\). The same considerations can be inferred with reference to Equation (15). The latter furnishes overtopping volume estimations with an accuracy not affected by the nose dimensions (Figure 10). However, the introduction of the reducing factors to consider the effect of the promenade does not allow us to predict \(\mathsf{q}_{\text{rear}}\)* with a satisfying amount of precision. Figure 10 demonstrates, instead, that the results derived by applying the Equation (17) of [41] are quite satisfactorily. In particular, the prediction results to be more reliable for \(\lambda=0.10\) than for \(\lambda=0.19\) and \(\lambda=0.29\). In the large and extra-large nose configurations, the predicting relation slightly overestimates the corresponding observations. The statistical parameters describing the reliability of Equations (11), (15) and (17) are reported in Table 4. These metrics confirm that Equation (17) is more precise than Equations (11) and (15), being characterized by a smaller value of NRMSE and a larger value of NSE. It is remarkable that the estimating equation provided by [41] for OBREC with a nose of increasing dimensions is affected by less-accurate statistical parameters (NSE = 0.78) than for the nose with only \(\lambda=0.10\) (NSE = 0.96).