Interactive approach for the sustainable stormwater management in medium-sized cities in Serbia – case study Pancevo

In the Republic of Serbia, stormwater systems are managed by the municipal public utility companies. Due to the political, economic and sociological situation in the last 25 years, development was not continuous, resulting in the numerous issues that need to be addressed. Most of them are related to the socio-economic aspects, capacity building and data. Example problems and viable solutions, for achieving sustainable management by public or private utility companies, are presented through the case study of city of Pancevo

Approximating optimal transport with linear programs

In the regime of bounded transportation costs, additive approximations for the optimal transport problem are reduced (rather simply) to relative approximations for positive linear programs, resulting in faster additive approximation algorithms for optimal transport.Comment: To appear in SOSA 201

Scrambling time from local perturbations of the rotating BTZ black hole

In this paper, we investigate the entanglement entropy of the rotating BTZ black hole perturbed by a massive back-reacting free falling particle. Then, mutual information between two finite intervals in two asymptotic regions of rotating BTZ is derived. It allows us to find the scrambling time, the time scale in which mutual information vanishes. We give a dual large $c$ CFT description in terms of a thermofield double state with different temperatures for left and right moving modes that is perturbed by a local operator. Exact matching between gravity and CFT results is obtained.Comment: 20 pages, 3 figure

Statistička analiza velikih voda Dunava i Save na području Beograda

The paper presents a methodology for analysis of the coincident annual maximum floods of the Danube and Sava Rivers at their confluence in Belgrade, as a part of the flood control project aimed to provide boundary conditions for the hydraulic modelling of the confluence sector. The Danube and Sava confluence is under back-water effect from the Iron Gate Reservoir. Estimating the probability of coincidence of floods at the Danube and Sava confluence is crucial for the efficient protection of Belgrade against floods because the Sava floods can have a significant contribution to the Danube floods. Due to the Iron Gate backwater effect, stream-flow measurements are not performed systematically near the Danube and Sava confluence at Belgrade. Flood assessment has therefore to be based on the data recorded at upstream gauging stations. Particularly, the only useful flood flows measurement data on the Danube upstream of Belgrade are available at the Bogojevo gauging station, which is located upstream of the confluence of the Tisa River with the Danube. This situation imposed that the design floods of the Danube immediately upstream of the Sava confluence should be estimated by considering coincident floods of the Danube at Bogojevo and of the Tisa River at Senta. The methodological approach in this paper has therefore included the establishment of a trivariate distribution of annual maximum floods of the Danube, the Tisa and the Sava rivers, based on the observed data. The identified trivariate distribution is then used in Monte Carlo experiments to simulate annual maxima of the Danube upstream of Tisa and of the Tisa, which were combined into the flood flows of the Danube upstream of Belgrade. This simulated flood series and the simulated Sava floods are then used for the assessment of the coincidence probability at the Danube and Sava confluence.U radu je prikazan postupak analize koincidencije maksimalnih godišnjih protoka na Dunavu i Savi u zoni Beograda, koja je specifična po tome što se nalazi pod usporom akumulacije Đerdap. Za efikasnu zaštitu od velikih voda u zonama ušća dve reke od ključnog značaja je procena verovatnoće koincidencije velikih voda obe reke, s obzirom da velike vode pritoke mogu uticati na velike vode glavne reke. U zoni Beograda posle uspostavljanja akumulacije Đerdap ne postoje sistematska merenja protoka, pa se računski protoci velikih voda i njihova koincidencija moraju proceniti na osnovu protoka na uzvodnim stanicama. Metodološki postupak sastojao se od analize godišnje koincidencije velikih voda Dunava, Tise i Save na osnovu raspoloživih podataka, pri čemu je određena trodimenzionalna raspodela velikih voda na ove tri reke kojom se uzima u obzir korelacija između pojave velikih voda na njima. Monte Karlo simulacijama iz dobijene trodimenzionalne raspodele formirana je raspodela velikih voda na Dunavu uzvodno od Beograda i određena koincidencija godišnjih maksimuma Dunava i Save kod Beograda

Statistička analiza velikih voda Dunava i Save na području Beograda

The paper presents a methodology for analysis of the coincident annual maximum floods of the Danube and Sava Rivers at their confluence in Belgrade, as a part of the flood control project aimed to provide boundary conditions for the hydraulic modelling of the confluence sector. The Danube and Sava confluence is under back-water effect from the Iron Gate Reservoir. Estimating the probability of coincidence of floods at the Danube and Sava confluence is crucial for the efficient protection of Belgrade against floods because the Sava floods can have a significant contribution to the Danube floods. Due to the Iron Gate backwater effect, stream-flow measurements are not performed systematically near the Danube and Sava confluence at Belgrade. Flood assessment has therefore to be based on the data recorded at upstream gauging stations. Particularly, the only useful flood flows measurement data on the Danube upstream of Belgrade are available at the Bogojevo gauging station, which is located upstream of the confluence of the Tisa River with the Danube. This situation imposed that the design floods of the Danube immediately upstream of the Sava confluence should be estimated by considering coincident floods of the Danube at Bogojevo and of the Tisa River at Senta. The methodological approach in this paper has therefore included the establishment of a trivariate distribution of annual maximum floods of the Danube, the Tisa and the Sava rivers, based on the observed data. The identified trivariate distribution is then used in Monte Carlo experiments to simulate annual maxima of the Danube upstream of Tisa and of the Tisa, which were combined into the flood flows of the Danube upstream of Belgrade. This simulated flood series and the simulated Sava floods are then used for the assessment of the coincidence probability at the Danube and Sava confluence.U radu je prikazan postupak analize koincidencije maksimalnih godišnjih protoka na Dunavu i Savi u zoni Beograda, koja je specifična po tome što se nalazi pod usporom akumulacije Đerdap. Za efikasnu zaštitu od velikih voda u zonama ušća dve reke od ključnog značaja je procena verovatnoće koincidencije velikih voda obe reke, s obzirom da velike vode pritoke mogu uticati na velike vode glavne reke. U zoni Beograda posle uspostavljanja akumulacije Đerdap ne postoje sistematska merenja protoka, pa se računski protoci velikih voda i njihova koincidencija moraju proceniti na osnovu protoka na uzvodnim stanicama. Metodološki postupak sastojao se od analize godišnje koincidencije velikih voda Dunava, Tise i Save na osnovu raspoloživih podataka, pri čemu je određena trodimenzionalna raspodela velikih voda na ove tri reke kojom se uzima u obzir korelacija između pojave velikih voda na njima. Monte Karlo simulacijama iz dobijene trodimenzionalne raspodele formirana je raspodela velikih voda na Dunavu uzvodno od Beograda i određena koincidencija godišnjih maksimuma Dunava i Save kod Beograda

Interactive approach for the sustainable stormwater management in medium-sized cities in Serbia – case study Pancevo

In the Republic of Serbia, stormwater systems are managed by the municipal public utility companies. Due to the political, economic and sociological situation in the last 25 years, development was not continuous, resulting in the numerous issues that need to be addressed. Most of them are related to the socio-economic aspects, capacity building and data. Example problems and viable solutions, for achieving sustainable management by public or private utility companies, are presented through the case study of city of Pancevo

Numerical simulation of the three-dimensional flow at the confluence of the Sava and Danube Rivers

In this paper, the confluence hydrodynamics at the mouth of the Sava and Danube Rivers in the city of Belgrade is analysed by means of the three-dimensional numerical model. The confluence offers excellent possibilities for such investigation as the two morphological features typical for a river confluence are present: bed elevation discordance at the entrance to the confluence and the scour hole in the post-confluence channel. The results are discussed in terms of the secondary flow pattern. Since the non-defomble bed is assumed, the nature of the river bed - flow interaction is analysed in terms of a non-dimensional bed shear stress and a re-suspension number distributions for different flow conditions in the confluence

Modeliranje sezonskih promena temperature vode akumulacije Ćelije

This paper presents the results of measurements and numerical modeling of water temperature changes in reservoir Celije in the period from April to October 2012. Reservoir Celije on the river Rasina, for many years attracts the attention of the general public and researchers, due to the importance of water management and impact of wastewater from the upper part of the basin. Reservoir Celije is a major source of PUC Krusevac Waterworks, but is also the recipient of municipal and industrial wastewater from the municipalities of Brus and Blace. Paper uses a two-dimensional model (CE QUAL W2), with transverse averaged hydrodynamic equations for the velocity and temperature field modeling in the vertical longitudinal plane. Data on the water temperature were collected in the field sampling campaigns, using multi - parameter probes. Model calibration enabled good comparison of measured and calculated temperatures, with average absolute deviation of about 0.7oC. For enhanced model performance, it would be necessary to reduce the uncertainty of the input data, which can be achieved by re- commissioning of the measuring station Ravni (upstream of the reservoir) and setting automatic weather station in the vicinity of the barrier.U radu je dat prikaz rezultata merenja i modeliranja sezonskih promena temperature vode u akumulaciji Ćelije u periodu od aprila do oktobra 2012. godine. Akumulacija Ćelije na Rasini, već duži niz godina privlači pažnju šire javnosti i istraživača, obzirom na vodoprivredni značaj i stepen ugroženosti otpadnim vodama iz gornjeg dela sliva. Akumulacija Ćelije je glavno izvorište kruševačkog vodovoda, ali je ujedno i recipijent komunalnih i industrijskih otpadnih voda iz opština Brus i Blace. U radu je korišćen dvodimenzionalni model (CE QUAL W2), sa poprečno osrednjenim hidrodinamičkim jednačinama za modeliranje polja brzina i polja temperatura u vertikalnoj podužnoj ravni. Podaci o temperaturi vode su prikupljeni u kampanjama terenskih merenja, primenom multiparametarskih sondi. Kalibracijom modela, postiglo se dosta dobro poklapanje izmerenih i izračunatih temperatura, sa prosečnim apslutnim odstupanjem od oko 0,7oC. Za unapređen učinak modela, potrebno bi bilo smanjiti neodređenost ulaznih podataka, što bi se postiglo ponovnim puštanjem u pogon merne stanice Ravni (uzvodno od akumulacije) i postavljanjem kompletne automatske meteorološke stanice u blizini pregradnog profila