# Flash Floods Hazard to the Settlement Network versus Land Use Planning (Lublin Upland, East Poland)
## 2 Study Area  
The study covered rural areas of eastern Poland covering the Lublin Upland and Roztocze (Figure 1). The bedrock of the region contains lithologically diverse Cretaceous and Paleogene carbonate rocks. Overlying these are Tertiary limestones and varied Pleistocene sediments--clays, sands, gravels, and loess. The surface of the Lublin Upland is highest in the central and eastern parts. In the northeastern and northwestern directions, it descends to an altitude of about 200 m above sea level. Individual mesoregions have the character of plateaus, plains, and hilly elevations. Roztocze forms a range of hills about 180 km long. The maximum heights here reach almost 400 m above sea level. The western part is characterized by the presence of a rolling top cut by dry valleys and ravines. In the central and eastern parts, there are poorly diversified and spur hills [50]. The loess-covered areas are characterized by the most varied terrain in places with a dense network of gullies. Annual precipitation is about 550-600 mm; in the Roztocze, it is slightly higher (600-650 mm), and the average unit outflow reaches 4.01/s-km\({}^{2}\). Precipitation occurs primarily in the summer season often in the form of downpours and thunderstorms. The Lublin Upland and Roztocze is an area of quite frequent occurrence of violent precipitation. Their sum reaches 20-30 mm and in some cases even 100 mm [19]. The duration of the precipitation can be short--from a few to tens of minutes. In the second half of the twentieth century, more than a dozen rainfalls with daily totals >100 mm were recorded. The geomorphological effects of some of them have been described in detail in Piaski Szlacheeckie in 1956, in Dzierzkowice in 1969, and in Kazimierz Dolny in 1981 [14]. The Lublin Upland and the western part of Roztocze is a typically agricultural region, with farmland occupying 70-80% of the area. The occurrence of fertile soils makes it an important agricultural production area in Poland. Population density ranges from 70 to 90 people per km\({}^{2}\) and is slightly lower than the average for Poland. A characteristic feature is the presence of a mosaic of crops resulting from the significant fragmentation of farms and fields [51]. Recently, there has been an expansion of the settlement network alongside a simultaneous decrease in the area used for agriculture due to depopulation and the aging rural population [52]. Central and eastern Roztocze is characterized by greater forest cover. It is protected within the Roztocze National Park and the system of landscape parks. The preliminary analysis covered 116 municipalities with a total area of 13,000 km\({}^{2}\). Ten municipalities with the highest building density, exceeding 4.7 buildings per square kilometer, were selected for analysis. The potential threat of episodic runoff is greatest in these regions. They are located in the southern part of Lublin Voivodeship, either in the Lublin Upland or Roztocze, in eastern Poland (Figure 1). The studied municipalities are characterized by various types of land relief--an important factor in flash floods. The most varied municipalities are Krasnobrod, where the local relief reaches 139 m and the average slope is 5.43\({}^{\circ}\), Szczebrzeszyn (133.6 m; 4.77\({}^{\circ}\)), and Zamosc (128.2 m; 2.63\({}^{\circ}\)). More intensive relief is found in the municipalities of Urzedow (108.6 m; 3.42\({}^{\circ}\)), Dzierzkowicz (106.2 m; 4.92\({}^{\circ}\)), Zakrzew (93.6 m; 4.25\({}^{\circ}\)), Trzydnik Duzy (93.3 m; 3.39\({}^{\circ}\)), and Poniatowa (81.2 m; 2.42\({}^{\circ}\)). In contrast, the municipalities of Glusk  
Figure 1: Location of studied municipalities (black polygons). Red outline—border of Lublin Upland. (55.3 m; 2.30\({}^{\circ}\)) and Wolka (59.0 m; 2.86\({}^{\circ}\)) have the least varied terrain. Studied municipalities are characterized by varying population density from 225 persons/km\({}^{2}\) in Glusk to only 35.3 persons/km\({}^{2}\) in Zakrzew (Table 1).