# Urban Flood Risk Assessment Based on a Combination of Subjective and Objective Multi-Weight Methods
## 3 Results and Analysis  
### Empowerment Results  
Through the combination of subjective and objective weighting, the weights of the indicators under different return periods in Liaocheng City were calculated and are shown in Tables 5-8. \begin{table}
\begin{tabular}{l l l l l l l l l} \hline \hline \multirow{2}{*}{**Target Layer**} & \multicolumn{3}{c}{**Criteria Layer**} & \multicolumn{3}{c}{**Indicator Layer**} & \multicolumn{3}{c}{**Nature**} \\ \cline{2-9}  & **Indicator** & **Weights** & **Indicator** & **Entropy Weight** & **CRITIC** & **AHP** & **Combination** & **Indicator** \\ \hline \multirow{9}{*}{Urban flood disaster risk} & \multirow{9}{*}{\begin{tabular}{} \end{tabular} } & Maximum 24 h & \multirow{9}{*}{0.1058} & Maximum 3-day & \multirow{9}{*}{0.0955} & Maximum 0.2518 & Positive \\  & & & rainfall (mm) & & & & \\  & & & rainfall (mm) & & & & \\  & & & Average annual & & & & \\  & & precipitation in & & & & \\  & Severity of & & moderate rainfall (mm) & & & & \\  & disaster-causing & 0.5396 & Average annual & & & & \\  & factors & precipitation of heavy & 0.1878 & 0.1722 & 0.0875 & 0.1526 & Positive \\ Urban flood disaster risk & & & rainfall (mm) & & & & \\  & & & Average annual & & & \\  & & precipitation of & 0.1345 & 0.1508 & 0.1170 & 0.1281 & Positive \\  & & & storms (mm) & & & & \\  & & Precipitation variability & 0.1505 & 0.1370 & 0.1363 & 0.1516 & Positive \\  & & Flood frequency & 0.0986 & 0.1130 & 0.1170 & 0.0704 & Positive \\ \hline \multirow{9}{*}{\begin{tabular}{} \end{tabular} } & \multirow{9}{*}{\
\begin{tabular}{} \end{tabular} } & \multirow{9}{*}{0.2970} & \multicolumn{3}{c}{**Entropy Weight**} & **CRITIC** & **Combination** & \\ \cline{3-5}  & & & River network density & & & & \\ \cline{3-5}  & & & (km/km\({}^{2}\)) & & & & \\ \cline{3-5}  & & & Average elevation (m) & 0.2359 & 0.2154 & 0.1899 & Negative \\  & & & Average slope (\%) & 0.2214 & 0.2432 & 0.2013 & Negative \\  & & & Vegetation cover (\%) & 0.3734 & 0.3489 & 0.4869 & Negative \\ \hline \multirow{9}{*}{
\begin{tabular}{} \end{tabular} } & \multirow{9}{*}{0.1958} & Population density & \multirow{9}{*}{0.1703} & \multirow{9}{*}{0.1037} & Maximum 0.1374 & Maximum 0.1374 & Maximum 0.1374 & Maximum 0.1374 & Maximum 0.1374 \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & & \\  & & & & & & \\  & & & & & & \\  & & & & & & & \\  & & & & & & \\ \end{tabular}
\end{table} 
Table 6: Weight in return periods of 50 years for flood risk assessment in Liaocheng City. \begin{table}
\begin{tabular}{l l l l l l l} \hline \hline \multirow{2}{*}{**Target Layer**} & \multicolumn{3}{c}{**Criteria Layer**} & \multicolumn{3}{c}{**Indicator Layer**} & \multicolumn{3}{c}{**Nature**} \\ \cline{2-7}  & **Indicator** & **Weights** & **Indicator** & **Entropy Weight** & **CRITIC** & **AHP** & **Combination** & **Indicator** \\ \hline \multirow{9}{*}{ \begin{tabular}{} \end{tabular}  } & \multirow{9}{*}{0.3108} & Maximum 24 h & \multirow{9}{*}{0.1058} & Maximum 0.1240 & 0.2050 & 0.1452 & Positive \\  & & & Maximum 3-day & \multirow{9}{*}{0.0955} & Maximum 0.1391 & 0.2518 & 0.1805 & Positive \\  & & & Average annual & & & \\  & Severity of & & moderate rainfall (mm) & & & & \\  & disaster-causing & 0.5396 & Average annual & & & \\  & factors & precipitation of heavy & 0.1878 & 0.1722 & 0.0875 & 0.1526 & Positive \\ Urban flood disaster risk & & & Farifall (mm) & & & \\  & & & Average annual & & & \\  & & & precipitation of & & & \\  & & & storms (mm) & & & \\  & & Precipitation variability & 0.1345 & 0.1508 & 0.1170 & 0.1281 & Positive \\  & & & Precipitation variability & & & \\  & & Flood frequency & 0.1505 & 0.1370 & 0.1363 & 0.1516 & Positive \\  & & & Flood frequency & 0.0986 & 0.1130 & 0.1170 & 0  
We used Equations (14) and (15) to calculate the risk, exposure, vulnerability, and comprehensive risk of flooding in Liaocheng City. We also adopted the natural discontinuity grading method.