## 2 Materials and Methods
### Computational Levels Defined
For each computational level the most relevant processes have been considered as presented in Table 3. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Spherical Domains** & \(\Delta\mathbf{\Lambda}\)\(\times\)\(\Delta\mathbf{\varphi}\) & \(\Delta\mathbf{t}\) (min) & _nf_ & _n\(\theta\)_ & _ng\(\lambda\)\(\times\)ngy = np_ \\ \hline Sph1—Black Sea (L1) & 0.08\({}^{\circ}\)\(\times\) 0.08\({}^{\circ}\) & 10 non-stat & 24 & 36 & 176 \(\times\) 76 = 13,376 \\ Sph2—Coastal driver (L2) & 0.02\({}^{\circ}\)\(\times\) 0.02\({}^{\circ}\) & 10 non-stat & 24 & 36 & 141 \(\times\) 141 = 19,881 \\ Sph3—Danube mouths (L3) & 0.01\({}^{\circ}\)\(\times\) 0.01\({}^{\circ}\) & 10 non-stat & 24 & 36 & 71 \(\times\) 61 = 4331 \\ Sph4—Southern RO1 (L3) & 0.01\({}^{\circ}\)\(\times\) 0.01\({}^{\circ}\) & 10 non-stat & 24 & 36 & 221 \(\times\) 221 = 48,821 \\ Sph5—Southern RO2 (L3) & 0.01\({}^{\circ}\)\(\times\) 0.01\({}^{\circ}\) & 10 non-stat & 24 & 36 & 161 \(\times\) 141 = 22,701 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of the computational domains defined in spherical coordinates for the Simulating Waves Nearshore (SWAN) model simulations focused on the western side of the Black Sea. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Cartesian Domains** & \(\Delta\mathbf{x}\)\(\times\)\(\Delta\mathbf{y}\) (m) & \(\Delta\mathbf{t}\) (min) & _nf_ & _n\(\theta\)_ & _ngx \(\times\)ngy = np_ \\ \hline Cart1—Sulina (L4) & 50 \(\times\) 50 & 60 stat & 30 & 36 & 135 \(\times\) 216 = 29,160 \\ Cart2—Sacalin (L4) & 200 \(\times\) 200 & 60 stat & 30 & 36 & 353 \(\times\) 251 = 88,603 \\ Cart3—Mangalia (L4) & 50 \(\times\) 50 & 60 stat & 30 & 36 & 96 \(\times\) 107 = 10,172 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Characteristics of the Cartesian computational domains considered for the SWAN model simulations focused on the western side of the Black Sea. \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline
**Input/Process** & _Wave_ & _Wind_ & _Tide_ & _Curr_ & _Gen_ & _Wcap_ & _Quad_ & _Triad_ & _Diffr_ & _Bfric_ & _Set up_ & _Br_ \\ \hline
**Domains** & 0 & X & 0 & 0 & X & X & X & 0 & 0 & X & 0 & X \\ \hline Sph1 & 0 & X & 0 & 0 & X & X & X & 0 & X & 0 & X & 0 & X \\ Sph2 & X & X & 0 & 0 & X & X & X & X & 0 & X & 0 & X \\ Sph3 & X & X & 0 & X & X & X & X & X & X & 0 & X \\ Sph4 & X & X & 0 & 0 & X & X & X & 0 & X & 0 & X \\ Sph5 & X & X & 0 & 0 & X & X & X & X & X & 0 & X \\ Cart1 & X & X & 0 & X & X & X & X & X & 0 & X \\ Cart2 & X & X & 0 & X & X & X & X & X & 0 & X & X \\ Cart3 & X & X & 0 & 0 & X & X & X & X & X & X & X \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Physical processes activated in the SWAN simulations, corresponding to the eight computational domains defined. X—process activated, 0—process inactivated. Figure 1: The computational domains defined in spherical coordinates: (**a**) Sph1—Black Sea basin and Sph2 (right side)—western coastal driver; (**b**) Sph3—nearshore area at the mouths of the Danube River (right side); Sph4 and Sph5 (left side)—Southern RO1 and RO2. The positions of the three Cartesian domains are also indicated. The geographical spaces corresponding to these three Cartesian computational domains (Cart1-Cart3) are illustrated in Figure 2.