Simon Rusjan

University of Ljubljana · Faculty of Civil and Geodetic Engineering

Forest vegetation is a very topical research subject as part of nature-based solutions for flood protection, soil erosion, water quality improvement, etc. However, limited capabilities of such measures are rarely investigated. Therefore, in this paper, study on the interplay of the hydrometeorological and seasonal forest vegetation role in regulati...

Afforestation is recognized as one of the commonly used nature-based solutions for flood risk mitigation as well as for reduction of anthropogenic impacts on sediment and nutrient flushing. Processes of nutrient cycles (e.g., nitrogen cycle) are directly dependent on the amount of precipitation and its temporal and spatial distribution as water is...

V prispevku so predstavljeni rezultati uporabe meritev koncentracij nitratnega dušika z 20-minutnim časovnim korakom v vodotoku Kuzlovec (območje občine Dobrova-Polhov Gradec) za namen konceptualizacije časovnega razvoja procesov oblikovanja padavinskega odtoka. V analizo je bilo vključenih 43 padavinskih dogodkov, ki so se zgodili v obdobju med ap...

Floods are among the most frequent and deadliest natural disasters, and the magnitude and frequency of floods is expected to increase. Therefore, the effects of different flood risk management options need to be evaluated. In this study, afforestation, permeable concrete implementation, and the use of dry and wet retention reservoirs were tested as...

Climate change implications of two karst catchments in Slovenia based on low- and high-flow indices.

In the paper, the determination of nitrate nitrogen (NO3-N) export regimes from the Kuzlovec catchment during rainfall events is presented employing various determination methods: the ratio of coefficient of variation of NO3-N concentration and discharge (CVC/CVQ), the slope of the regression line to the points of concentration and discharge logari...

Increases in the frequency of flood events are one of the major risk factors induced by climate change that lead to a higher vulnerability of affected communities. Natural water retention measures such as afforestation on hillslopes and floodplains are increasingly discussed as cost-effective alternatives to hard engineering structures for providin...

The karst aquifer of the Ljubljanica River catchment, which has numerous springs and sinks, presents an interesting environment for studying hydrogeological processes. This study aims to explore the behavior of U isotopes and to evaluate their use as tracers of hydrogeochemical processes as an alternative to classical geochemical tracers (i.e., phy...

This poster presents an analysis of relationships between hydro-meteorological and biogeochemical processes from the perspecti-ve of the time of ocurrence of the centroids of discharge, NO3-N load, and volumetric soil moisture diagrams. Analysis is made on event basis. Data are obtained from our own measurements on a small, forested experimental ri...

Understanding the temporal variability of the nutrient transport from catchments is essential for planning nutrient loss reduction measures related to land use and climate change. Moreover, observations and analysis of nutrient dynamics in streams draining undisturbed catchments are known to represent a reference point by which human-influenced cat...

This study attempts to assess the consistency of various low-flow indices evaluated at 12 water stations in the Ljubljanica river catchment, Slovenia, which is due to its high diversity of hydrogeological properties recognized as a non-homogenous catchment. Daily discharge data were used in the study for evaluating low-flow statistics (baseflow ind...

V prispevku so predstavljeni rezultati analize nizkih pretokov na 11 vodomernih postajah na reki Ljubljanici in njenih pritokih. Za vsako od postaj smo izračunali nabor različnih kazalnikov nizkih pretokov, ki jih lahko razdelimo v tri skupine: statistike nizkih pretokov, kazalniki sezonskosti nizkih pretokov in recesijska analiza hidrograma. Rezul...

Understanding and prediction of low-flow conditions are fundamental for efficient water resources planning and management as well as for identification of water-related environmental problems. This is problematic especially in view of water use in economic sectors (e.g., tourism) where water-use peaks usually coincide with low-flow conditions in th...

In this paper we analyse the influence of three different calculation criteria on the values of low-flow recession constants, namely the influence of the calculation method, recession curve segment length (4, 5, 6, or 7 days) and of the selected period (whole period, monthly, seasonally) for the calculation of the initial discharge, which determine...

Karst systems can be generally characterised by their high hydrological heterogeneities related mainly to highly variable permeabilities, which can significantly change over small spatial scales. This makes tracing and quantification of water flow pathways an extremely demanding task. In this study we present an analysis of hydrological characteris...

In this paper we analyse the influence of three different calculation criteria on the values of low-flow recession constants, namely the influence of the calculation method, recession curve segment length (4, 5, 6, or 7 days) and of the selected period (whole period, monthly, seasonally) for the calculation of the initial discharge, which determine...

It is not clear how projected climate change will impact the hydrological functioning of complex catchments that have significant karst characteristics. Therefore, in this paper we focused on the investigation of the low- and high-flow characteristics of the karst Ljubljanica River catchment. One smaller (51 km2) and one larger (1135 km2) catchment...

Nutrients such as nitrates (NO3-) are biologically reactive solutes. Their exports from catchments are controlled by a combination of hydrometeorological conditions and biogeochemical processes. In order to be able to study the dynamics of control mechanisms for nutrient flushing, high-frequency measurements are required, especially discharge data...

UNESCO Chair on Water-related Disaster Risk Reduction - ppt presentation in pdf at World Construction Forum WCF2019, Ljubljana, April 2019.

Erozijske procese v hudourniških strugah je običajno zelo težko količinsko ocenjevati. Na podlagi podrobnega terestričnega laserskega skeniranja (TLS) odseka struge hudournika Kuzlovec v povirnem delu porečja reke Gradaščice smo ovrednotili spremenljivost hidromorfoloških razmer po lokalnem ekstremnem padavinskem dogodku, ki se je zgodil avgusta 20...

Small river basins, where the forest is the main land use, represent the natural land use in the climatic conditions typical for Slovenia. Hydrological conditions are reflected in the properties of individual precipitation events, such as, for example, the intensity and/or duration of precipitation. In order to improve our understanding about the i...

In the case of ungauged catchments, different procedures can be used to derive the design hydrograph and design peak discharge, which are crucial input data for the design of different hydrotechnical engineering structures, or the production of flood hazard maps. One of the possible approaches involves using a hydrological model where one can calcu...

Combination of stable isotopes measurements and more frequently used measurements such as rainfall or discharge data observations can be used to investigate hydrological characteristics of the nonhomogeneous catchments. For example, with stable isotopes flow paths of rainfall water to the river network can be determined and mean residence times can...

Suspended sediment load (SSL) observations are usually less frequent than precipitation and river discharge measurements; therefore a reliable procedure is needed for the estimation of SSL. One year of precipitation, SSL, and discharge measurements at 20-min intervals were performed at the Kuzlovec torrent in Slovenia. The Frank copula was selected...

By using stable oxygen and hydrogen isotopes in hydrological studies one can obtain answers to questions that are difficult to answer with standard hydrological measurements. For example, with stable isotopes we can determine where the water goes when it rains and identify the flow paths of rainfall to the streams. This paper shows theoretical back...

Since all of the questions in hydrology cannot be answered with hydrological measurements, hydrologists have been applying stable isotopes analyses for several decades in their research. For example, with stable isotopes flow paths of rainfall to the streams can be identified and mean residence time can be estimated. Only with traditional measureme...

During two consecutive years the monitoring of rainfall nitrate (NO3⁻) and ammonium (NH4⁺) concentrations, combined with high-frequency measurements of streamwater NO3⁻ concentrations, provided insight into the mechanisms controlling the dissolved inorganic nitrogen (DIN) budgets of the forested Padež stream catchment in SW Slovenia. During both ye...

Erosive rainfall events can cause significant problems in agriculture and other fields because of fertile soil losses. Therefore, high-frequency measurements of rainfall data are useful in order to improve our knowledge about this issue. This study presents rainfall measurements in years 2013, 2014 and 2015 at two locations in central Slovenia, nam...

In the last decade hydrological science in the world has changed significantly. Numerous new methods have been introduced and also the way how hydrological problems are approached has changed dramatically. That is true also for the hydrological science in Slovenia. The present review of selected hydrological studies contributing to the advancements...

Extreme events such as flash floods and debris flows are frequent phenomena that occur in steep torrential catchments; these kinds of events can cause notable geomorphic changes. Repeated terrestrial laser scanning (TLS) surveys were performed in a steep forested catchment of the Kuzlovec torrent (drainage area ~ 0.7 km2) in central Slovenia, where...

Hydrological extremes such as flash floods can cause large economic loss and even endanger human lives. Small, step and forested torrential catchment named Kuzlovec (~ 0.7 km2), a part of the Sava River basin, is located west of the capital city Ljubljana and is one of the experimental catchments in Slovenia. Flash flood event occurred in the inves...

The article describes the cartographic and hydraulic modelling of the Kuzlovec torrent in the Polhov Gradec Hills. The torrent is situated in forest covered area, formed by steep slopes, rocks and numerous cascades. Terrestrial laser scanning was used to collect the data for the DTM production , which was used as a model for the mathematical modell...

This report provides the results of Work Package 7 (WP7). WP7 focuses on the integration of methodological approaches across scales and provides guidelines for policy development in the context of sediment and large wood management. Two guidelines with methodological explanations and good practice examples are provided as expected output of this WP...

The simple dynamical system approach was implemented to analyze, explain and simulate streamflow fluxes in diverse seasonal hydrological conditions within the forested Padež stream catchment in SW Slovenia. The catchment is characterized by the flushing, torrential hydrological response conditioned by the flysch geological settings of a low hydraul...

Soil degradation is a major environmental problem in many parts of the world, including Slovenia. The spatially distributed WATEM/SEDEM model can be used to identify the most critical parts of the catchment with regard to soil erosion. Five Slovenian (Central Europe) catchments with inhomogeneous topography, land use, geological conditions, hydro-m...

The aim of the study was to estimate the sediment budget (net erosion change) in a small torrential catchment using the DEM of difference (DoD) approach. The Kuzlovec torrent (∼ 0.7 km2; in the Gradaščica River catchment) is located approximately 20 km west of the City of Ljubljana and is part of the Sava River basin. The elevation ranges between 3...

Flow in natural mountain torrents is very complex and typically characterized by non-linearity due to high roughness, steepness, wide range in torrent sediment sizes, presence of large woody debris, etc. Such flow is highly turbulent and difficult to describe with Eulerian grid-based methods. Smoothed Particle Hydrodynamics (SPH) method is a suitab...

V okviru raziskave smo izdelali digitalni model reliefa (DMR) hudournika Kuzlovec. Hudournik leži gozdu, oblikujejo ga strma pobočja, skale in številne kaskade. Za izdelavo DMR smo območje posneli s terestričnim laserskim skenerjem. Izdelan DMR smo uporabili za preučitev vpliva velikih drevesnih ostankov (debel) na hidrodinamiko vodnega toka in izv...

Climate changes have a high impact on river discharges and therefore on floods. There are a few different methods we can use to predict discharge changes in the future. In this paper we used the complex HBV model for the Vipava River and simple correlation between discharge and precipitation data for the Soča River. The discharge prediction is base...

The paper presents a review of structural mea- sures that were taken to cope with floods in some cities along the Danube River, such as Vienna, Bratislava, and Belgrade. These cities were also considered as case studies within the KULTURisk project. The structural measures are reviewed and compared to each other according to the type, duration of a...

Eksperimentalna porečja, ki so pogosta tudi v svetovnem merilu, so pomemben dejavnik pri razvoju hidrologije, saj nam omogočajo opazovanje in proučevanje različnih procesov, kot so padavine, površinski odtok, premeščanje sedimentov, procesi erozije, itd. V prispevku so predstavljeni nekateri merski instrumenti, s katerimi smo opremili dve sosednji...

A simple dynamical system approach was implemented in order to analyse, explain and simulate streamflow fluxes in diverse seasonal hydrological conditions. The study was implemented within 42 km2 forested Padež stream catchment in SW part of Slovenia, which is characterized by flushing, almost torrential hydrological response conditioned by flysch...

The optimal solution for complex flood management is integrated approach. Word »integration« used very often when we try to put something together, but should distinguish full multiple integrated approach of integration by parts when we put together and analyse only two variables. In doing so, we lost complexity of the phenomenon. Otherwise if we t...

In karst basins a strong mutual interaction between streamflow and groundwater is often observed and can affect flood formation and runoff propagation. Aiming at characterising the runoff regime of the transnational Vipava/Vipacco karst basin (650km2, Eastern Alps, SLO/I), which is a case study of the FP7 KULTURisk research project, the natural gro...

The paper presents a critical review of structural measures that were taken to cope with floods in some cities along the Danube River, such as Vienna, Bratislava, Belgrade, and Barcolennette area along the Ubaye River. These cities are also taken as case studies within the KULTURisk project. The structural measures are critically reviewed and compa...

Sediment transport in catchments is an important aspect of environmental research because of its role in the transport of sediment-associated nutrients, pesticides and other contaminants. High turbidity levels in water bodies affect stream morphology, aquatic organisms and their habitats, cause siltation of water reservoirs and have other side effe...

In the contribution, the flood protection problematic of the capital of the Republic of Slovenia, the Ljubljana city, is presented. Ljubljana lies in the southern part of the Ljubljana basin, crossing the moor on the south and the north of Ljubljana field. The tectonic subsidence of the area in the geological past has made it an important confluenc...

This document provides a critical review on the use of structural measures for water related risks. Focus is given to the following topics: lessons learned from past flood defense strategies and new perspectives; structural measures in landslides and slope constructions; structural measures and return period; deterministic versus probabilistic desi...

Rainfall kinetic energy–intensity relationships for rainfall erosivity estimation were established on the basis of raindrop size distribution measurements performed in the Brkini hilly area in southwest Slovenia, a transitional area between the Mediterranean and continental climate conditions. A set of measurement instruments, an optical disdromete...

Seasonal and diurnal variations of in-stream NO3-N concentration oscillations were studied through high-frequency measurements of streamwater’s physical, chemical parameters (in-stream NO3-N concentration, water temperature, dissolved oxygen, pH) and hydrometeorological variables (stream discharge, solar radiation) under hydrologically stable condi...

A variability of seasonal changes in the diurnal in-stream NO3-N concentration oscillations was studied through high-frequency measurements of the stream-water's physical, chemical parameters (in-stream NO3-N concentration, water temperature, dissolved oxygen, pH) and hydrometeorological variables (stream discharge, solar radiation) under hydrologi...

The Reka river is the widest known sinking stream of the Classical Karst area in Slovenia, and it has been studied since the Antiquity. The river sinks into the Škocjan Cave system, which was proclaimed by UNESCO as a World Heritage Site in 1986. The Reka river basin is situated in the southern part of Slovenia and has an area of 442 km2 and a mean...

Raindrop size distribution measurements for rainfall erosivity estimation in the Reka river basin, SW Slovenia

During a weather front that passed over large parts of Slovenia on 18.9.2007, extreme rainfall events were triggered causing several severe flash floods with six casualties. Out of 210 municipalities in Slovenia, 60 were reporting flood damages, and the total economic flood damage was later estimated at close to 200 million Euro; highest damage was...

Accurate discharge estimation is important for an efficient river basin management and especially for flood forecasting. The traditional way of estimating the discharge in hydrological practice is to measure the water stage and to convert the recorded water stage values into discharge by using the single-valued rating curve .Relationship between th...

The Reka river is the widest known sinking stream of the Classical Karst area in Slovenia, and it has been studied since the Antiquity. The river sinks into the Skocjan Cave system, which was proclaimed by UNESCO as a World Heritage Site in 1986. The Reka river basin is situated in the southern part of Slovenia and has an area of 442 km2 and a mean...