Hydrosphere. Hazard processes and phenomena http://hydro-sphere.ru/index.php/hydrosphere Для почтовых отправлений: 199155 Санкт-Петербург, а/я 136, Редакция журнала «Гидросфера. Опасные процессы и явления» / For mail: 199155 St. Petersburg, PO Box 136 Editorial Board of the «Hydrosphere. Hazardous processes and phenomena». en-US Hydrosphere. Hazard processes and phenomena 2686-7877 ENVIRONMENTAL IMPACT OF USING SMALL RIVER FOR LOG DRIVING http://hydro-sphere.ru/index.php/hydrosphere/article/view/40 <p>The paper considers the issue of the log diving effect on the ecological status of small rivers and their catchments. There are analyzed the circumstances leading to the prohibition of the log driving and the consequences of this decision for nature and man.</p> <p>The main points of both positive and negative effects of the log driving are evaluated and specific steps are proposed for reducing the chemical and mechanical pollution of water bodies. A general conclusion is made that the damage to ecosystems from log driving is not as great as is it commonly believed. There is proposed specific reclamation plan with the aim of improving the recreational capabilities of small rivers, purifying water, improving the condition of the forest stock by reducing the flooding of its territory.</p> <p>The affected problem concerns both the condition of small rivers and the future of the logging industry and the related development of outlying areas that are currently experiencing large demographic and economic problems. The arguments presented by the authors show that in a nowadays economic situation, the prohibition of log driving is economically disadvantageous and even harmful. It impedes the further development the territories of the Russian North, Siberia and the Far East. The hypothetical damage to nature by log driving is not comparable with the consequences that cause as a result of the desolation of the huge territory of Russia. There are a confirmed decline in the economy, the come-down of the demographic situation and socio-cultural infrastructure today. Over the past decades the catastrophic situation has developed in the demography of the Trans-Ural regions and other regions of Siberia. Unfortunately, the great number opened in recent decades mines and processing plants are not designed for constant abode of the population. Settlements near such enterprises have a temporary status. Only the logging and wood processing industry can save this situation. So, an integrated approach to the problem of log driving can facilitate a new development&nbsp; stage of outlying areas.</p> Alexey Yu. Vinogradov Tatiana А. Vinogradova Mariya M. Kadatskaya Svetlana I. Sazonova Sergey V. Hvalev Copyright (c) 2020 https://creativecommons.org/licenses/by/4.0/ 2019-12-30 2019-12-30 1 4 533 554 10.34753/HS.2019.1.4.533 ASSESSMENT OF ROUGHNESS COEFFICIENT VALUE http://hydro-sphere.ru/index.php/hydrosphere/article/view/36 <p>The article considers one of the main parameters while conducting water management calculations – the roughness coefficient. Up-to-date assessment of its value is carried out according to special tables or by calculation. Article presents various methods for calculating the roughness coefficient – from the reverse evaluation using the Chezy formula by the measurements to the empirical relations obtained by various specialists on the basis of field studies. In addition, the authors considered formulas for calculating the roughness coefficient based on physics. The results of calculations obtained for such formulas best fit their values obtained in the inverse way from the Chezy formula. The calculation methods presented in the article were tested on the data of gauging station on the river Polist' – near the settlement Podtopol'e for the period of 1954 year and on the river Gozovka – near the settlement Goza for the period 2014-2017.</p> <p>Behind comparing the results of measurements, calculations for various formulas and estimated tabular data, the authors made the following conclusions. Pressure losses in explicit depends on the depth of the stream and the slope of the free surface, the last one implicitly characterizes the frictional of the channel. At the same water flow rates, a change in the roughness coefficient can reach tens of percent. With different filling of the channel, the roughness coefficient can change by several times, which predetermines the corresponding errors in the tabular estimation of the roughness coefficient, even for a simplified case – only for an open channel. Therefore, all the dependencies, taking into account only the granulometric of riverbed deposits, basically can not have practical application.</p> <p>General conclusion: even with the same water level for simplified conditions of an open channel without vegetation, the roughness coefficient can differ by several times, which nullifies all attempts to theoretically evaluate it in the absence of direct measurements of slope, speed, and average depth.</p> Alexey Yu. Vinogradov Tatiana А. Vinogradova Viktor A. Obyazov Mariya M. Kadatskaya Copyright (c) 2020 https://creativecommons.org/licenses/by/4.0/ 2019-12-30 2019-12-30 1 4 462 476 10.34753/HS.2019.1.4.462 ON THE INFLUENCE OF ICE COVER ON THE UNDERGROUND COMPONENT OF RIVER FLOW http://hydro-sphere.ru/index.php/hydrosphere/article/view/37 <p>The river network is the main drainage of underground waters of the territories. It is created over a long period and is determined by geological, climatic and orographic conditions. The draining capacity of a hydrographic network depends not only on its density, but also on the speed of water flowing down it. The latter is determined by the area of the living section, slope, roughness of the riverbed. The article shows that the river ice of the Northern rivers, as a seasonal hydraulic resistance, can also have a significant impact on the drainage capacity of the hydrographic network. On the example of river flow in warm and cold winters, it is shown that the ice cover regulates the participation of groundwater at different levels of drainage in the formation of river flow. As the climate warms, the regulatory role of the ice cover decreases. The rate of underground water treatment in the upper sections of river basins increases, accompanied by an increase in water content in the lower parts of the hydrographic network. Over the past 30-40 years, the contribution of groundwater in the watershed of the river basins to the supply of rivers in the forest zone in mezhen decreased by 20% compared to the previous "quasi-stationary" climate period. There is a "drying" of the upper reaches of river basins, despite the growth of annual precipitation. In the future, if the current trends of climate change continue, it is possible to further reduce the underground supply of rivers, as the drainage role of the hydrographic network will increase. The reduction of groundwater reserves in river basins will reduce their regulatory role in river flow and may increase the frequency of occurrence of extremely low water content. This should be taken into account when developing adaptive water management measures to climate change.</p> Mikhail L. Markov Elena V. Gurevich Copyright (c) 2020 https://creativecommons.org/licenses/by/4.0/ 2019-12-30 2019-12-30 1 4 477 489 10.34753/HS.2019.1.4.477 THE STUDY OF THE DEBRIS-FLOWS DYNAMICS ON AN EXPERIMENTAL STAND http://hydro-sphere.ru/index.php/hydrosphere/article/view/38 <p>Designed and manufactured a test stand for the dynamic characteristics of debris-flows and for physical modelling of debris-flows. The stand is a rectangular cross-section tray with a length of 3.0 m, a width of 0.25 m, a depth of 0.25 m. The slopes of the tray vary from 10<sup>o</sup> to 45<sup>o</sup>. Rods are installed in the tray to accommodate load cells for measuring pressure, speed and temperature. The process of moving the debris-flow through the transparent wall of the debris-flow tray is filmed by a high-speed video camera. During the experiment, the velocity and high- velocity pressure of water flow and artificial debris-flow were measured. The tray was installed with a slope of 12<sup>o</sup>. Water flow was started up on the tray (to measure the flow rate and the value of the velocity head, which were then used as reference values). Then the tray was put into the flow of the prepared debris-flow mixture. The debris-flow mixture was prepared from a dredged-crushed proluvial-deluvial deposits of Holocene age with a loamy aggregate with a density of 2210 kg/m<sup>3</sup>. The density of the prepared debris-flow mixture was 1756 kg/m<sup>3</sup>. Dynamic viscosity of the debris-flow mass measured by the Stokes method was 0.0498 Poise, kinematic viscosity of the debris-flow mass was 0.0928 Stokes. Data on the debris-flow velocity measured directly during its movement of the debris-flow is not enough. Therefore, methods for calculating the speed of a debris-flow slide in its are important. One of these methods is the method of calculating the debris-flow velocity by the magnitude of the speed head (on the traces of the debris-flow on the trunks of trees). That method is based on the formula of E. Torricelli. The results of the experiment showed that the measured debris-flow velocity, calculated from the magnitude of the velocity head, was lower than the measured velocity before the obstacle and higher than the measured velocity after the obstacle. The measured velocity of the debris-flow passage of the entire tray was close to the calculated one.</p> Nikolay A. Kazakov Darya A. Bobrova Ekaterina N. Kazakova Svetlana V. Rybal'chenko Copyright (c) 2020 https://creativecommons.org/licenses/by/4.0/ 2019-12-30 2019-12-30 1 4 490 503 10.34753/HS.2019.1.4.490 POSSIBILITIES OF CATCHMENT’S TRANSPIRATION ASSESSMENT BASED ON SAP FLOW MEASUREMENTS: THE PROBLEM STATEMENT http://hydro-sphere.ru/index.php/hydrosphere/article/view/39 <p>Study of seasonal dynamics and evapotranspiration volume of forested catchments (mainly forest stand transpiration) is the relevant objective for fundamental knowledge and practical applications. However, there are many difficulties: labor efforts of direct observations, many factors affecting against each other, observational data scaling and so on. As a result, evapotranspiration during hydrological modeling is determined by the leftover principle and simplified techniques, leading to wrong representation of water balance structure.</p> <p>The presented article deals with the first results of our research group focused on setting up field measurements of xylem sap flow using trunk sap flow measuring sensors as well as development of sap flow assessment methods for individual trees and whole catchment.</p> <p>The investigations were performed for mixed coniferous-broad leaved forests at the territory of the Central Sikhote-Alin’ within Verkhneussuriyskiy biogeocenotical station of FSC of the East Asia Terrestrial Biodiversity FEB RAS. This site is used for water balance measuring surveys from 2011. Sap flow was measured continuously during June-October of 2019 on one of the local dominant tree species. Apparently, such investigations are novel for the Russian Far East region.</p> <p>It is expected that direct sap flow measurements for individual trees refinement methods, data scaling and its integration to the hydrometeorological observations will help to make a comprehensive analysis of catchments water balance and to integrate measured data into hydrological models.</p> Tatiana S. Gubareva Sergei Yu. Lupakov Boris I. Gartsman Vladimir V. Shamov Alexey V. Rubtsov Nadezhda K. Kozhevnikova Copyright (c) 2020 https://creativecommons.org/licenses/by/4.0/ 2019-12-30 2019-12-30 1 4 504 532 10.34753/HS.2019.1.4.504 THOUGHTS ABOUT HYDROLOGY http://hydro-sphere.ru/index.php/hydrosphere/article/view/41 <p>Vade mecum</p> <p>Listen. If you are a hydrologist or going to become once of them, then let me tell you the truth about this science. About hydrology. Of course, this truth will be what it seems to me. But believe me, it’s unlikely that I have grave rivals regarding the disclosure of scientific secrets. But first, I want to ask you some questions.</p> <p>What is the destiny of the water that fell from Heaven to Earth? And if you answer this question, then you are a master of the amazing.</p> <p>But you know that flowing is inherent in water. Therefore answer - in what ways water flows. And if you are ready to answer this question, then you are certainly a master of the amazing.</p> <p>And one more thing. What would happen if there were no water on Earth? What happens on Earth with the participation of water? What happens to water during its stay on Earth? And if you again know the answers, then truly you are a master of the amazing.</p> <p>And if it so happened that you found it difficult to answer, or answered hesitantly, or in some way committed a sin against the truth and felt this, then come with me. And believe me, I'm also a little master of the amazing.</p> <p>I will remind you about the beauty of this World and its vulnerability. About the exclusive role of water on Earth and the problems associated with this. About how important and wonderful it is to feel and understand everything about water.</p> <p>I will tell you about the people who gave answers to the questions asked to you. And about people who thought they knew the answers. And about people who answered without knowing the answers.</p> <p>And I also hope that you will understand the main thing – only devotion and obsession can lead you to real knowledge. And only then can you become a true master of the amazing.</p> <p>"But enough. Let me get down to matter. Let me start and let me finish."</p> Yurii B. Vinogradov Copyright (c) 2020 https://creativecommons.org/licenses/by/4.0/ 2019-12-30 2019-12-30 1 4 555 589 10.34753/HS.2019.1.4.555