## 4 Results
### Cascading Events  
In recent years, the main damage caused by storm surges, high-intensity rainfall, and sea level rise has often come from the cascade of these events rather than a single strong factor [6]. The impact of storms on WWTPs is also a result of a cascade of storm surge, sea level rise, and rainfall. Therefore, this study also explored the impact of the three-factor cascading event on the buildings of the WWTP based on the sub-basin. Through GIS, this study analyzed the flood depth when a cascade event of 100 years of rainfall, sea level rise, and storm surge C1 occurred in 2050, which was used to evaluate the impact  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**WWTPs** & \multicolumn{3}{c}{**Amount of Damage (Thousands of USD)**} \\ \cline{2-4}
**in NYC** & **SLOSH C1** & **SLOSH C2** & **FEMA Sandy** \\ \hline Port Richmond & 34,000 & 80,000 & 60,000 \\ Oakwood Beach & 4800 & 18,000 & 24,000 \\ Tallman Island & 0 & 60,000 & 80,000 \\ Rockaway & 4800 & 18,000 & 24,000 \\ Jamaica & 0 & 48,000 & 0 \\ Bowery Bay & 0 & 60,000 & 60,000 \\ Hunts Point & 0 & 80,000 & 80,000 \\ Red Hook & 34,000 & 80,000 & 20,000 \\ Owls Head & 10,000 & 60,000 & 80,000 \\ Newtown Creek & 122,400 & 288,000 & 288,000 \\ Coney Island & 0 & 60,000 & 80,000 \\
26 th Ward & 16,000 & 80,000 & 80,000 \\ North River & 80,000 & 80,000 & 80,000 \\ Wards Island & 0 & 172,800 & 216,000 \\ \hline SUM & 306,000 & 1,184,800 & 1,172,000 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Comparison of the amount of damage related to the FEMA MOTF Sandy, SLOSH C1, and C2 hurricanes.  
of the cascade event on the NYC WWTPs. Sea level will rise by 7 to 12 inches [18], and the intensity of the 100 year rainfall in 2050 is 4.14 in/h (10.52 cm/h) as projected by the New York State Energy Research and Development Authority (NYSERDA). A study conducted by [PERSON] et al. also utilized similar sea level rise trends to develop coastal adaptation to climate change in NYC [45]. This analysis can help understand which factor plays a more significant role in the flood caused by cascading events. The study utilized the linear summation of the constituents to simulate the extreme flooding events for the WWTPs based on the total water level (TWL) concept. Several studies have also adopted similar methodology to simulate the extreme total water levels. For example, research conducted by [PERSON] and [PERSON] (2014) simulated the elevation of the TWL considering linear summation of four different component (i.e., storm surge, sea level rise, rainfall, and wave run-up) to explain the total contribution from mean sea level, astronomical tides, wave run-up, and nontidal residuals [46]. Therefore, the present study utilized a similar approach to quantify the total water level.  
Table 7 shows the maximum total flood depth in 2050 when the 100-year rainfall, sea level rise, and storm surge C1 occurred simultaneously. Although a hydrodynamic model would be necessary to get the precise assessment of flood depth and inundation extent based on cascading events, this study presents a preliminary estimation of flood depth due to the contribution of extreme events occurring simultaneously. Results showed that storm surge had the largest impact on the flood depth around the WWTP. The rainfall only affected the Port Richmond WWTP and the Newtown Creek WWTP. However, sea level rise had no impact on the 14 WWTPs according to our study, but a more comprehensive approach with hydrodynamic modeling must be conducted with proper boundary conditions to further justify the outcome from the cascading events.