Povezanost fluvialnega premeščanja suspendiranih snovi z drugimi hidrološkimi procesi : doktorska disertacija

Bezak, Nejc (author), Mikoš, Matjaž (mentor), Šraj, Mojca (comentor)

Razumevanje in poznavanje procesov, ki sestavljajo vodni oziroma hidrološki ter erozijskosedimentacijski krog, ki se medsebojno prepletata, je pomembno z vidika varstva pred naravnimi nesrečami ter zagotavljanja ustreznih pogojev za življenje (npr. pitna voda). V doktorski disertaciji so obravnavani naslednji procesi: uvialno premeščanje suspendiranih snovi, površinski odtok vode, padavine ter erozijski procesi. V disertaciji so najprej opisani in predstavljeni hidrološki procesi, sledi opis merskih metod, ki so bile uporabljene za izvedbo meritev. Nadalje je podan opis obravnavanih porečij vključno z eksperimentalnim porečjem, kjer so se meritve z visoko frekvenco vzorčenja izvajale v okviru doktorske disertacije, sledi opis uporabljenih statistično-matematičnih metod, ki so bile uporabljene za analizo podatkov, pri tem je poudarek na funkcijah kopula, ki omogočajo hkratno analizo dveh ali več v naravi bolj ali manj odvisnih spremenljivk. V zadnjem poglavju prvega dela disertacije pa so prikazane osnove modeliranja erozije tal s poudarkom na modelu WATEM/ SEDEM. V drugem delu disertacije so prikazani rezultati različnih terenskih meritev (npr. meritve uvialnega premeščanja suspendiranih snovi, padavin, pretokov, erozije tal), izvedena je analiza povezanosti uvialnega premeščanja suspendiranih snovi z drugimi hidrološkimi procesi, prikazani so rezultati modeliranja erozije tal ter uporabe funkcij kopula. Ugotovili smo, da imajo padavinski dogodki velikih intenzitet nadpovprečen vpliv na procese sproščanja, premeščanja in odlaganja erozijskega materiala. Količine premeščenega materiala so lahko pri teh dogodkih nekaj velikostnih razredov večje od dolgoletnega povprečja. V Sloveniji do nastopa konice uvialno premeščenih suspendiranih snovi večinoma prihaja pred nastopom konice pretoka, pri tem pa so časovne razlike večinoma relativno majhne (do 1 dneva). Nadalje se količine uvialno premeščenih suspendiranih snovi v slovenskih vodotokih večinoma zmanjšujejo, kar je lahko posledica različnih vzrokov, kot sta zaraščanje površja zaradi opuščanja kmetijske obdelave ter zapiranje rudnikov. Z aplikacijo modela WATEM/SEDEM na 5 porečjih v Sloveniji je bilo ugotovljeno, da se koeficient odplavljanja zmanjšuje z večanjem prispevnega območja. Funkcije kopula pa so bile uporabljene za multivariatne verjetnostne analize poplavnih dogodkov, kjer smo hkrati upoštevali konice pretokov, volumne visokovodnih valov ter trajanja visokovodnih valov, poleg tega pa smo funkcije kopula uporabili tudi za analizo podatkov o suspendiranih snoveh ter za ocenjevanje vrednosti uvialno premeščenih suspendiranih snovi na podlagi podatkov o pretokih in padavinah.

• Language: Slovenian
• Keywords: grajeno okolje, sedimenti, erozija tal, modeliranje, funkcije kopula, eksperimentalno porečje
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Place of publishing: Ljubljana
• Publisher: [N. Bezak]
• Year: 2016
• PID: 20.500.12556/RUL-82755
• UDC: 556.512:551.311.21:(497.12):(043)
• COBISS.SI-ID: 7476065
• Publication date in RUL: 02.06.2016

BEZAK, Nejc, 2016, Povezanost fluvialnega premeščanja suspendiranih snovi z drugimi hidrološkimi procesi : doktorska disertacija [online]. Doctoral dissertation. Ljubljana : N. Bezak. [Accessed 27 June 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=82755

Secondary language

• Language: English
• Title: Fluvial transport of suspended sediments related to other hydrologic processes : doctoral thesis

Abstract

Understanding and knowledge about the processes that define water or hydrologic cycle and erosion-sedimentation cycle (these two cycles are inter-connected) is important in order to ensure safety during natural disasters and to provide suffcient conditions for life (e.g. drinkable water). In the presented thesis we investigated next processes: uvial transport of suspended sediments, surface runoff, rainfall and erosion processes. Firstly, the investigated hydrological processes are described, then the measuring methods are presented. Further, the investigated catchments including experimental catchment where high-frequency measurements were performed are described, in the next section the statisticalmathematical tools that were used for data analysis are shown. The emphasis was given to the copula functions that can be used for simultaneous study of two or more (in)dependent variables that define the environmental process. In the last section of the first part of thesis, the basic concepts of soil erosion modelling are presented where the emphasis was given to the WATEM/SEDEM model that can be used for soil erosion modelling. In the second part of the thesis, results of field measurements are presented (e.g. measurements of uvial transport of suspended sediments, rainfall, discharge and soil erosion), analysis of connection between uvial transport of suspended sediments and other hydrological processes was carried out, soil erosion modelling results are described and application of copula functions is shown on practical examples. The main conclusions are: rainfall events that have large rainfall intensities have significant impact on erosion, transport and deposition processes. During these kinds of events the suspended sediment budgets can be for a few orders of magnitude larger than the long-term annual rates. In Slovenia the peak of the suspended sediment transport mostly occurs before the peak discharge but the time differences are rather small (up to 1 day). Moreover, the trends in the transport of suspended sediments in Slovenian streams are mostly negative (all statistically significant trends are negative). Reasons for this can be: closing of mines or foresterisation (abandoning of farming due to urbanisation). Application of the WATEM/SEDEM model showed that sediment delivery ratio decreases with increasing catchment area. Moreover, copula functions were used for multivariate ood frequency analysis where peak discharge, hydrograph volume and hydrograph duration were considered in the analysis. Moreover, copula functions were also used to analyse suspended sediment data and for the estimation of the suspended sediment values based on the measured discharge and rainfall values.

• Keywords: building environment, sediments, soil erosion, modelling, copula functions, experimental catchment