Using WaTEM/SEDEM and HEC-HMS models for the simulation of episodic hydrological and erosion events in a small agricultural catchment

Abstract

A careful analysis of rainfall-runoff events and patterns of sediment and pollution load to water bodies is crucial for the proper management of agricultural land. This study simultaneously employed the WaTEM/SEDEM long-term erosion model and the HEC-HMS episodic hydrological and erosion model to describe the runoff and sediment load evoked by extreme rainfall events in a small agricultural catchment in Czechia, using the long-term monitoring discharge and water quality episodic data. WaTEM/SEDEM helped to delineate the runoff and sediment critical source areas, subsequently incorporated into HEC-HMS. The acquired results showed that the spatial distribution of land use is a fundamental factor in the protection of watercourses from diffuse pollution sources and the transport and delivery of sediment profoundly depends on the status of crop cover on arable land near a watercourse. Integrating both models, it was shown that the tabulated Curve Number (CN) values as well as the average C-factor values had to be lowered for the majority of the modelled events to match the monitored data. A noticeable role of catchment runoff response most probably played tile drainage, which appeared to profoundly modify the episodic runoff pattern. This study showed a promising approach for the simulation of different rainfall-runoff responses of small agricultural catchments and could be applied for the delineation of areas where soil conservation measures or protective management is of high priority. The results further revealed the obvious need to revise the CN values for tile-drained catchments.

Improvement of SCS-CN Initial Abstraction Coefficient in the Czech Republic: A Study of Five Catchments

“…High e values indicated the model's over-estimating tendency in this specific catchment, probably due to improper CN determination. This might have been caused by the high percentage (97.3%) of arable land along with the presence of the tile drainage systems [78]. In other words, the results revealed quite specific hydrologic conditions in KO-1 catchment compared to the other two KO catchments.…”

“…The KO-1 catchment has an opposite arrangement, as maximal rain intensity and P have the highest loading values in PC1 and P 10d and P 5d in PC2. This might be caused by the high percentage of arable land with presence of tile drainage system [78]. In such environment, P 10d and P 5d do not play the most influential role.…”

Hydrological Modeling of Upper OumErRabia Basin (Morocco), Comparative Study of the Event-Based and Continuous-Process HEC-HMS Model Methods

“…We analyzed LULC change and climate variability relationship with hydrologic processes in the UOERRB. The HEC-HMS model was selected for the study as it is: widely used to assess hydrology and water availability in agricultural catchments around the world [54] [55] [56] [57]; open source and user-friendly in relations to handling input data [58]. HEC-HMS is a semi-distributed conceptual hydrological model potentially capable of spatio-temporal simulations of rainfall-runoff relations within a basin [59] [60].…”

MODELAGEM DE EROSÃO E APORTE DE SEDIMENTOS EM BACIA HIDROGRÁFICA COM O MODELO WaTEM/SEDEM

“…Liu e Fu (2016) observaram, na bacia Nianzhuang, China, que as principais fontes de sedimentos são as áreas localizadas nas encostas declivosas diretamente conectadas aos rios, reservatórios e planícies de inundação utilizadas para a agricultura, nas quais a diferença entre saída e entrada de sedimentos atinge valores positivos elevados. Konečná et al (2020) observaram na pequena bacia de Na Hrebelci, situada nas terras altas da Boêmia-Morávia, República Tcheca, a partir da modelagem de erosão com o WaTEM/SEDEM, que as principais fontes de sedimentos foram as áreas agrícolas localizadas nas proximidades da rede de drenagem, e que os sedimentos produzidos em áreas mais distantes foram, em sua maioria, depositados nas vertentes devido à presença de usos da terra que reduziram o volume do escoamento superficial.…”