A Preliminary Study of Field Scour Morphology Downstream of Block Ramps Located at River Bends

Most of the studies present in the literature deal with block ramps located in straight channels. This is an evident limitation not allowing for a generalization of laboratory model findings. Generally, these structure typologies are located in natural rivers, that are characterized by both quasi-straight branches and bends. In particular, the location of the structure in river bends contributes to deeply modify both the upstream in-flow conditions and the downstream erosive mechanism. Only recently, the scour process downstream of block ramps was analyzed in curved channels and useful relationships were proposed to compute the maximum scour depth. Furthermore, the mentioned analysis was supported by field data validation, resulting in the understanding of the effects of river curvature on downstream scour process in the presence of a protected stilling basin. Despite of the recent study on the topic, there is still a lack of knowledge regarding the equilibrium morphology configuration and the effect of hydraulic parameters on the erosive process. Based on field measurements collected at the Porębianka river (Poland) after flood events, this paper aims to deep the downstream scour hole characteristics and the erosive dynamics. In particular, both the effects of in-flow conditions and river curvature are analysed in terms of resulting equilibrium morphologies, highlighting both similarities and differences with the corresponding configurations occurring in quasi-straight river branches

Block Ramps in Curved Rivers: Morphology Analysis and Prototype Data Supported Design Criteria for Mild Bed Slopes

Eco-friendly river restoration structures are a valid solution for river training projects. Among this structure typology, block ramps have been successfully tested to solve problems related to river sediment control, bed stabilization and energy dissipation. Despite the conspicuous literature dealing with block ramps design in straight rivers, there are no studies analysing the erosive process occurring in the stilling basin downstream of a block ramp in a curved river bend. Therefore, this paper represents the first systematic analysis of their behaviour and of the resulting downstream equilibrium morphology in such geometric configuration. A dedicated model was built to simulate a wide range of hydraulic conditions. Experimental data analysis allowed describing the erosion dynamics occurring in the stilling basin and, at the same time, to derive a useful design relationship by which it is possible to estimate the maximum scour depth. Furthermore, the model results were successfully validated by using field measurements collected in the Porebianka River (Poland). Both field data and laboratory experimental results allowed furnishing a comprehensive description of the scour phenomenon. The proposed relationship represents the first trustable and valid tool for hydraulic design of such structure typology in curved rivers

Adjustment of the river channel due to block ramps introduction: Porębianka mountain creek, Polish Carpathians

The paper includes a description of 25-five interlocked boulder block ramps with increased roughness located on Porębianka creek and presents an analysis how those low head hydraulic structures fit to a natural river system: riffle-pool. These block ramps with increased roughness structures might be called "close to the nature", and in hydraulics engineering they are replacing traditional drop hydraulic structures. One of the main advantages of block ramps is that they are supposed to be placed in a natural sequence distances which follows pools and riffles pattern along a river, also block ramps allows free movement of fish upstream and downstream without necessity of fish pass constructio

Gravel bed river scouring analysis downstream of block ramp (example from the Poniczanka stream in Ponice village)

Praca dotyczy rozmycia nieumocnionego dna cieku poniżej bystrza o zwiększonej szorstkości na potoku Poniczanka w miejscowości Ponice. Obliczono głębokość rozmycia dna poniżej budowli wykorzystując formuły empiryczne różnych autorów. Wyniki obliczeń zweryfikowano z rezultatami pomiarów terenowych, typując formuły, których uzyskane wyniki były o największej zgodności z obserwacjami terenowymi, jak i te o najgorszej. Celem pracy jest weryfikacja formuł obliczeniowych głębokości rozmycia dna poniżej bystrza na podstawie wyników badań terenowych. Stwierdzono, że zależności empiryczne służące do obliczenia głębokości rozmycia dna poniżej bystrza są niedokładne, ale mogą służyć do analizy porównawczej.The work describes the scouring process downstream of boulder block ramps on Poniczanka Stream in Ponice village. The depth of the down-stream scouring rate was calculated using empirical formulae due to different authors. The results of the calculations were verified basing on the field measurements. Finally only those formulae which results were most consistent with field observations and those with were the worst consistent with field observations are presented along a paper. Thus the aim of the study was to verify the existing formulae of the scouring depth calculation downstream of block ramp hydraulic structure on the basis of the results of field research. It was found that the empirical relationships for calculating the scouring depth in observed case are not satisfied enough, however they can be used for comparative analysis for designers

Wpływ rumoszu drzewnego na granulometrię osadów korytowych

Celem artykułu jest określenie wpływu, jaki wywiera zdeponowany w korycie rzeki rumosz drzewny na granulometrię rumowiska dennego. Analiza obejmowała doprądową i zaprądową stronę badanych form depozycyjnych rumoszu drzewnego. Zakres prac obejmował ustalenie geometrycznych wymiarów analizowanych rumoszów drzewnych, określenie składu granulometrycznego rumowiska dennego w sąsiedztwie tych form, wyznaczenie długości ich oddziaływania na materiał denny oraz ustalenie zależności między geometrycznymi wymiarami rumoszów drzewnych a zasięgiem ich oddziaływania na rumowisko denne. Badania granulometryczne wykonano na podstawie analizy sitowej. Zasięg oddziaływania form depozycyjnych rumoszu drzewnego ustalono wykonując analizę statystyczną z wykorzystaniem współczynnika efektywności Nasha-Sutcliffe’a. Zależności pomiędzy zasięgiem oddziaływania a wymiarami badanych form rumoszu drzewnego określono na podstawie współczynnika korelacji Spearmana. Stwierdzono, że rumosz drzewny zdeponowany w korycie rzeki Raby wpływa na granulometrię rumowiska dennego, zarówno po stronie zaprądowej, jak doprądowej. Wykazano również, że zasięg oddziaływania na uziarnienie materiału dennego po stronie zaprądowej form depozycyjnych rumoszu drzewnego jest w znacznym stopniu zależny od wysokości zdeponowanego rumoszu drzewnego

Public policy clause in recognition and enforcement proceedings

Niniejsza praca ma na celu przedstawienie instytucji klauzuli porządku publicznego w postępowaniu o uznanie lub wykonanie zagranicznych wyroków arbitrażowych. Klauzula porządku publicznego jest instrumentem umożliwiającym sądom odmowę uznania lub wykonania wyroku arbitrażowego w przypadku, gdy skutki takiego uznania lub wykonania byłyby sprzeczne z podstawowymi zasadami porządku prawnego w danym państwie. W pracy przeprowadzona została analiza pojęcia klauzuli na gruncie innych dziedzin prawa, takich jak prawo prywatne międzynarodowe czy międzynarodowe postępowanie cywilne, z których to klauzula została zapożyczona do arbitrażu handlowego. Główna część pracy dotyczy analizy pojęcia porządku publicznego na gruncie międzynarodowego arbitrażu handlowego w odniesieniu do przepisów arbitrażowych Kodeksu postępowania cywilnego, oraz Konwencji o uznawaniu i wykonywaniu zagranicznych wyroków arbitrażowych. W tej części pracy przeanalizowane zostały takie problemy jak m.in.: zakres badania wyroku przez sąd krajowy, podział na krajowy i międzynarodowy porządek publiczny, rodzaje definicji porządku publicznego stosowane przez sądy zagraniczne. W ostatniej części pracy, na podstawie międzynarodowego orzecznictwa, dokonana została klasyfikacja naruszeń porządku publicznego.The purpose of this thesis is to analyze the public policy clause in recognition and enforcement proceedings. The clause is a legal device enabling national court to refuse recognition on enforcement of the awards which recognition would be contrary to the fundamental legal principles of that country. The analysis of the public policy was conducted with respect to other, than arbitration, fields such as international private law and international civil proceedings, from which public policy clause has been adopted. The main part of the thesis refers to public policy in the meaning of international commercial arbitration. This part is based on understanding of public policy with respect to both Civil code of procedure and Convention on recognition and enforcement of foreign arbitral awards. In this part problems such as: the scope of state court examination, distinction on domestic and international public policy and the understanding of public policy by state courts were considered. In the last part of the thesis, the qualification of possible violations of public policy clause was made, due to the courts decisions

Granite pebbles in architecture of the Podtatrze region

In the second half of the 20th century in the Podtatrze region, which includes four ethnographic regions: the Podhale, Orava, Spisz and Pieniny, a fashion developed for the use of granite pebbles in regional construction. In this paper, the authors describe the origins of these pebbles, characterize them as a building material and present their use in local construction

Impact of Floods on Sediment Trap Efficiency of a Small Shallow Reservoir—A Case Study

Silting is the main factor limiting the ability to perform the tasks that small reservoirs are intended for. Therefore, the change in sediment trap efficiency was studied for a small shallow reservoir, Krempna, which, due to high silting intensity, was desilted twice (2005, 2018). Siltation measurements were performed in two periods (1987–2005, 2006–2018) after the reservoir was desludged. It was found that the sediments were composed of fine-fraction sediment; therefore, a series of measurements of suspended sediment transport were performed. These data allowed us to calculate the daily sediment transport flowing into and out of the reservoir and water-level measurements. Then, the sediment trap efficiency was calculated. The aim of this study was: (1) to determine the impact of flood flows on the sediment trap efficiency (STE) of a small shallow reservoir, (2) to determine changes in the value of the sediment trap efficiency of a small shallow reservoir in two different periods of its operation, and (3) to demonstrate whether it is possible to determine the value of the initial sediment trap efficiency and changes in the STE values during operation using empirical formulas. Finally, during flood flows, the amount of sediment retained in the studied reservoir was several times lower than during freshets with a much smaller flow. It is these small freshets that reduce the capacity of the reservoir. A correlation relationship was developed for 18 data—flood flows (Q) and sediment trap efficiency (STE)