Hydrological and hydraulic analysis of a small lowland watercourse flow capacity and its functioning in the region of Silesian Lowlands in the context of rainfall water management

Abstract

Abstract Hydrological and hydraulic analysis of a small lowland watercourse flow capacity and its functioning in the region of Silesian Lowlands in the context of rainfall water management. The built-up areas in the catchments of small lowland watercourses faced with the risk of particularly devastating natural hazards. This risk is especially prevalent in the mouth reaches. The increasingly intense extreme natural phenomena, such as violent floods and long lasting droughts, increase the importance of irrigation, drainage and hydraulic structures. This paper presents the results of a comprehensive hydrological and hydraulic analysis of the functioning of a small lowland watercourse flow capacity in the context of water management in its catchment. The case study discussed below is a proposal that could be used by both the specialists and the designers working in the field of water management. Methods are proposed for the determination of heavy rainfall in small ungauged agricultural catchments for the purpose of rainfall water management. The area under study consists of the lower reaches of R-4, a watercourse located in the agricultural village of Dobrzeń Wielki in the Opolskie province, the Upper Odra river basin. The authors have assessed the flow capacity of R-4 based on EN 752:2008 and carried out hydrological calculations for the area being analysed as well as hydraulic calculations for R-4. It was concluded, that the small lowland watercourse and the communication structures (culverts and pipelines) on its way indicated low flow capacity. Consequently, a rainfall water management concept was proposed for the water flowing in the watercourse. A small retention reservoir with a total capacity of 3,132 m3 and a surface area of 2,088 m2 was also proposed to be constructed. In order to calculate the water inflow to the reservoir the Bogdanowicz and Stachy formula was used. This model was selected because the maximum rainfall on agricultural land calculated from this formula meets the requirements of EN 752:2008. Moreover, this formula produced the highest runoff values compared to other models. The research carried out is in line with the goals of water management in rural areas, where the management model has changed.