Author(s): Barbora Jachymova; Tomas Dostal; David Zumr; Josef Krasa; Miroslav Bauer; Nina Noreika; Tailin Li

Linked Author(s): Barbora Jáchymová, Tomáš Dostál, David Zumr, Miroslav Bauer, TAILIN LI

Keywords: Infiltration; Rainfall-runoff event; Surface runoff; Retention capacity

Abstract: Catchment retention capacity depends on many factors and conditions. At present, we are increasingly faced with insufficient retention capacity of the landscape due to inappropriate and unsustainable management. Unsustainable land use, insufficient care of the agricultural landscape, compaction of the subsoil and climate change and the associated change in the distribution of precipitation over time result in a higher frequency of rainfall-runoff events, which lead to intensive surface runoff. The decrease in the ability of the landscape to retain water then results in number of negative impacts on water management, infrastructure, the land itself and the affected municipalities. There is a drying out of the soil, a reduction in fertility and an overall degradation of the soil on the one hand. On the other hand, the infrastructure of municipalities is demaged, local flood events occur, and the nutrient balance is disturbed and the water quality in reservoirs decreases. Therefore, there is a significant demand for increasing the retention capacity of the landscape. In addition to the overall improvement of landscape care, which leads to increased natural retention (eg increased share of organic matter in the soil, sustainable agriculture and modern agrotechnical practices), it is possible to increase retention in the basin through appropriate design and location of retention elements (infiltration ditches, small water reservoirs). The location of these elements makes it possible to retain rainwater in the landscape more effectively and at the same time has a significant impact on the protection of the affected municipalities and hydrographic network against increased runoff and nutrient supply. Designing these measures is a complex process. Appropriate design requires careful consideration of inputs (precipitation total, retention capacity of the catchment itself, land use, the necessary level of the affected infrastructure protection, etc.). The paper presents a possibility to assess the importance of retention elements (infiltration ditch or a small reservoir) in terms of the retention capacity of the catchment increasing. The effectiveness of the designed elements in terms of increasing retention in the river basin is significantly affected by the real situation in the catchment. The presented paper defines the most important input conditions that affect the retention elements capacity. It evaluates the situation in the river basin in terms of retention capacity for real soil conditions, land use and various rainfall intensity. Subsequently, the increase of the retention capacity of the catchment after the basic type of retention elements implementation is monitored. The change in retention is evaluated for a wide range of input conditions.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221518

Year: 2022