Authors:Zuzana Sabová, Zuzana Németová, Tatiana Kaletová, and Silvia Kohnová
The objective of the study is an assessment of a Ratka small water reservoir in Slovakia by using two main aspects, i.e., the hydrotechnical, geotechnical and environmental aspects.
An evaluation of the actual state of a small water reservoir was solved in a complex way. Based on the field measurements, the quality of surface water was controlled in order to check if the surface water quality indicators meet the requirements of government regulations. In addition to the terrain measurements, laboratory measurements were performed. The results assess the actual state of the small water reservoir in details, including an assessment of the water quality with proposed measures for improving the condition of the water reservoir.
Authors:Zuzana Németová, Silvia Kohnová, and Romana Marková
Regional flood frequency analysis is considered to be an important and popular method for estimating different hydrological variables at ungauged sites. The estimation of the index flood is the essential problem when this method is applied. The objective of the study is a comparison of the estimation of the mean annual flood (or index flood) by using two approaches based on the ‘so-called’ index flood method and top-kriging. The concept behind these methods permits estimating the mean annual flood at ungauged locations using information taken from gauged sites located within the same homogeneous pooling groups. The study area comprises 104 gauging stations on the whole territory of Slovakia. The observation period of the annual maximum discharges of the selected stations was from 1961-2010. The identification of the homogeneous pooling group was performed using a non-hierarchical k-means clustering algorithm. The optimal number of clusters is determined by the Silhouette method. As a result, eight homogeneous pooling group clusters were identified. Finally, the results of the estimated mean annual floods using the index flood method and top-kriging were compared with the observed data. Top-kriging provided better results than the classical index flood method for estimating the mean annual flood at ungauged sites.
Authors:David Honek, Zuzana Németová, Silvia Kohnová, and Monika Šulc Michalková
The modeling of soil erosion processes is affected by several factors that reflect the physical-geographic conditions of the study site together with the land use linkage. The soil parameters are significant in the modeling of erosion and also runoff processes. The correct determination of a soil's parameters becomes a crucial part of the model's calibration. This paper deals with a sensitivity analysis of seven soil input parameters to the physically-based Erosion 3D model. The results show the variable influence of each soil parameter. The Erosion 3D model is very sensitive to initial soil moisture, bulk density, and erodibility.
Authors:Zuzana Németová, David Honek, Tamara Látková, Monika Šulc Michalková, and Silvia Kohnová
The scope of this study is an evaluation of potential soil water erosion using the physically-based erosion model, EROSION-3D. This model is event-based and calculates soil water erosion during an actual measured rainfall event. The calculations of the erosion model take advantage of a digital elevation model, precipitation and soil parameters, which are established in a specific parameter catalogue. The soil water erosion was modeled in two small catchments in the Myjava Hill Land (Slovakia), using 9 soil moisture scenarios and two different crops on arable areas. When considering the last 35 years of rainfall records at the Myjava meteorological station, three storm rainfall events were applied in the modeling. The results were statistically analyzed to figure out the differences between the model’s functional possibilities; the modeling under the various scenarios proved a strong interaction between the values of the input factors and the results of the soil erosion.