ICE JAM MITIGATION ON BISTRITA RIVER THROUGH HYDRAULIC CONTROL STRUCTURES

Author(s):  
Costel Bofu
2020 ◽  
Author(s):  
N. I. Tananaev ◽  
V. A. Efremova ◽  
T. N. Gavrilyeva ◽  
O. T. Parfenova

Abstract Spring floods in Siberia annually affect local communities. Major urban settlements in the region implemented flood control structures, so rural areas take a heavy beating. In 2018, spring floods severely hit multiple communities in central Yakutia, exposing deficient flood prevention and risk management practices. Notably, Amga village, an important local center, was severely inundated. Hydrological analysis shows that the 2018 flood had a 50-yr return period, and was caused by an ice jam in a nearby channel bend where mid-channel sand bars impede ice movement during breakup. The cold spells of late April and early May in the middle section of the river promote ice-jam development, causing extreme water stage rise. Highest water stage is unrelated to either winter snow water equivalent or early May rainfall. Estimated tangible direct damage to the Amga community equals 5.1B ($81.5M) in 2018 prices, but only 0.13B ($2.1M), or 2.5% of this total, was reclaimed. A questionnaire survey revealed that most residents report important deterioration of drinking water quality and health after flooding. Residents respond positively to risk mitigation actions, implemented by the local and regional authorities, except ice dusting and cutting, and report minor activity of official sources in spreading information on flood progress.


1985 ◽  
Vol 12 (3) ◽  
pp. 559-566 ◽  
Author(s):  
S. P. Chee ◽  
E. M. Yuen

In any riverbed degradation phenomenon, the vertical dimension of the deepest part of the scour hole is a pertinent parameter since all the other erosion parameters describing the configuration of the scour hole depend on its numerical value. Hence, it is necessary to be able to evaluate the maximum depth of the scour hole.For most practical situations, the impingement of submerged water jets on a granular riverbed occurs at an angle, and it is the object of this study to include the effects of obliqueness in the analysis. Some examples of the effects of impingement by water jets are the erosion problems caused by plunging water jets from hydraulic control structures as they discharge into the tail-water downstream.Basic to an understanding of the mechanism of local scour is the concept of "initiation of motion." Hence, the analytical study will use this concept to derive generalized relations that will link the incipient motion condition at the deepest point of the scour hole with the numerical value of the scoured depth. In addition, care was taken to ensure that only those hydraulic variables that are frequently used in hydraulic engineering design are included in the analysis in order to make the results useful to practicing engineers. Key words: local scour, maximum erosion, river bed, plunge basin, diving jets, energy dissipation, riverbed degradation.


1991 ◽  
Vol 18 (6) ◽  
pp. 933-939 ◽  
Author(s):  
Darryl J. Calkins

Ice control structures placed in the streamwise direction of a river were analyzed to determine the effectiveness in reducing ice jam thicknesses. The theory describing the thickness for “wide” river ice jams was modified to analyze these longitudinal types, providing the computational verification that ice jam thicknesses could be reduced where the mode of ice cover thickening is internal collapse. These longitudinal structures appear to provide a new tool for modifying the river ice regime at freeze-up and possibly at breakup. By decreasing the ice jam thicknesses, which leads to lower stages, the structures have the potential for decreasing ice jam flood levels. The structures' ability to function is independent of the flow velocity and these structures should perform in rivers with velocities greater than the usual limitation of roughly 1 m/s associated with conventional cross-channel ice booms. Other possible applications include controlling ice movement at outlets from lakes, enhancing river ice cover progression, or even restraining the ice cover at breakup. A U.S. patent application has been filed jointly by the author and the U.S. Army Corps of Engineers. Key words: river ice, ice jams, ice control, hydraulic structures, ice booms.


2013 ◽  
Vol 15 (2) ◽  
pp. 321-334 ◽  
Author(s):  
Ophélie Fovet ◽  
Xavier Litrico ◽  
Gilles Belaud ◽  
Olivier Genthon

Open-channel distribution networks are subject to algal developments that can induce major disturbances such as clogging of hydraulic devices (pipes, weirs, filters, flow meters). Flushes can be used as a strategy to manage these algae developments. A flush is carried out by increasing the hydraulic shear conditions using hydraulic control structures of the canal network. In response to the shear stress increase, a part of the fixed algae is detached, then re-suspended into the water column, and finally transported downstream. This leads to a peak of turbidity that has to be controlled. In this paper, we develop a distributed linear model of the turbidity dynamics that is used for real-time adaptive control of the flushes. Simulations show the effectiveness of the adaptive controller, which can, at the same time, estimate the gain of the system, linked to the amount of initial fixed biomass, and perform a flush without exceeding the turbidity limit.


2020 ◽  
Vol 2 (2) ◽  
pp. 78-85
Author(s):  
Ali Yildiz ◽  
◽  
Ali Ihsan Marti ◽  
Alpaslan Yarar ◽  
Volkan Yilmaz

Dams and hydraulic structures are used for the supply and control of water, which have great importance on human life. The sluice gate is one of the hydraulic control structures. Sluice gates release excess water from the reservoir to the downstream side in a controlled manner with a certain discharge for controlling the level of the reservoir. A hydraulic jump is created to dissipate the energy of flow coming from under the gates. A hydraulic jump occurs when the flow regime is changed from subcritical to supercritical. However, the position of the hydraulic jump in the channel should be known exactly to prevent damage to surrounding structures. In this study, an open channel system with a sluice gate is used to produce a hydraulic jump. Experiments are conducted for two different gate openings (a1=1.5 cm and a2=2 cm) and 16 discharge values. For each case, the position of the hydraulic jump is determined. In addition, flow depths at 5 different points were measured including before and after the hydraulic jump. The results obtained from the experimental study were compared with the numerical model in terms of the position of hydraulic jump and flow depths. According to the results obtained, the numerical model and the physical model showed between 80 and 91% consistency.


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