# Flash Floods Hazard to the Settlement Network versus Land Use Planning (Lublin Upland, East Poland)
## 4 Results  
### Spatial Diversity of Catchment Susceptibility  
In each municipality, buildings have been identified that may be affected by flash floods (Table 4). Numbers range from 652 in Dzierzkowicz municipality to 2668 in Zamosc municipality. In terms of municipalities with a high share of threatened buildings in the total number, Szczebrzeszyn (21.8%) and Zakrzew (20.5%) stand out. The lowest shares are in Zamosc (9.8%) and Trzydnik (10.5%). The remaining six municipalities' shares range from 13 to 19%. The subindices used to assess the susceptibility of the analyzed catchments show great variation in each of the municipalities (Table 5). The average share of arable land in the catchments ranges from 51.1% (Urzedow) to 88.9% (Zakrzew), with the highest values reaching 100%. The average share of forested area within the studied catchments across a single municipality ranges from 0.7% (Zamosc) to 10.8% (Krasnobrod). The individual catchment with the largest forested area was in Poniatowa (49.9%) and the smallest (1.1%) in Gusk. The average catchment area is greatest in Zamosc (0.16 km\({}^{2}\)) and smallest in Dzierzkowicz (0.1 km\({}^{2}\)). The biggest catchment area exceeds 8 km\({}^{2}\) in Poniatowa, Urzedow, and Zamosc. The steepest average slope (4.3\({}^{\circ}\)) was found across catchments in Krasnobrod and the lowest in Poniatowa (2.5\({}^{\circ}\)), while the highest value in a single catchment was 17.2\({}^{\circ}\) in Dzierzkowicz. The highest mean value of relative elevation (34.9 m; local relief) was found across catchments in Krasnobrod and the lowest (13.3 m) across catchments in Wolka. The highest relief in an individual catchment (104.4 m) was recorded in Szczebrzeszyn. The distribution of maximum values of catchment circularity was broad, ranging from 0.33 (Dzierzkowicz) to 0.47 (Trzydnik). The average slope of the drainage line ranged from 2.1\({}^{\circ}\) (Poniatowa) to 3.8\({}^{\circ}\) (Dzierzkowicz), and the individual area with the highest area slope was in the catchment area in Szczebrzeszyn, at 18.9\({}^{\circ}\). The average density of the road network ranged from 6.6 km/km\({}^{2}\) (Krasnobrod) to 4.5 km/km\({}^{2}\) (Zakrzew). The highest value was 47.7 km/km\({}^{2}\) (Zakrzew). The largest number of catchments (2979) were classified as category 3 for susceptibility, and this category dominated in each municipality both numerically (Table 6) and in terms of area (Table 7). In second place, numerically speaking, came category 2 (1437). In terms of the share of area across all catchments, category 2 catchments (Table 7) were also the second most common in most municipalities, with the exception of Dzierzkowicz, Krasnobrod, Szczebrzeszyn, and Zakrzew, where category 4 catchments covered a larger relative area. Category 4 was in third place in terms of the number of catchments (844) and in terms of \begin{table}
\begin{tabular}{l c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**Municipality**}} & **Number of Buildings in the** & **Share of Buildings Located** \\  & **Municipality** & **on Potential Flowlines [\%]** \\ \hline Dzierzkowicz & 652 & 13.0 \\ Gusk & 1444 & 18.5 \\ Krasnobrod & 1024 & 15.6 \\ Poniatowa & 922 & 14.5 \\ Szczebrzeszyn & 1981 & 21.7 \\ Trzydnik Duzy & 677 & 10.5 \\ Urzedow & 1022 & 13.6 \\ Wolka & 838 & 12.4 \\ Zakrzew & 796 & 20.5 \\ Zamosc & 2668 & 9.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Number of buildings located on flowlines (threatened by flash floods) in relation to the number of buildings in the municipality. area in most municipalities. Category 1 (153 catchments) ranked fourth, and the shares of its area did not exceed 1% in six municipalities. An exception here was the municipality of Wolka, where the share of category 1 catchments exceeded 7%. The highest category (55 catchments) was found in seven municipalities and was most represented in Zakrzew (19), where it also occupies the largest area (2.64%).