Assessing the Characteristics of the Maximal Spring Flood Runoff in the Don Basin under Nonstationary Conditions

2020 ◽  
Vol 47 (6) ◽  
pp. 945-952
Author(s):  
N. V. Osipova ◽  
M. V. Bolgov
Author(s):  
L. N. VASILEVSKAYA ◽  
◽  
I. A. LISINA ◽  
D. N. VASILEVSKII ◽  
◽  
...  

Based on daily runoff volumes of four large Siberian rivers (the Ob, Yenisei, Lena, and Kolyma) for 1936-2018, the regime and changes in the total annual and seasonal runoff are analyzed. High synchronous and asynchronous correlations between monthly river runoff and atmospheric circulation indices of hemispheric and regional scales are revealed. In recent decades, the total annual runoff and its variations have increased (the rate of increase is most pronounced for the Kolyma River). A change in water content within a year is heterogeneous: weak positive trends are characteristic of the spring flood runoff and the summer-autumn period, and a significant increase occurred in the winter months. High correlations with a 1-8-month shift made it possible to identify the most informative regions, the atmospheric circulation over which makes a certain contribution to the variance of river runoff.


2005 ◽  
Vol 9 (18) ◽  
pp. 197-221 ◽  
Author(s):  
Pierre Cazalis

The abundant spring run-off in Southern Québec is a result of the heavy winter precipitation and the length of the retaining period. One half of the annual discharge occurs in March, April and May, yet the maximum monthly coefficient (April) on the Saint-François is little more than 300. This low figure is due to the length of the thawing season, which extends the flood over at least four weeks, and to the retaining action of the numerous lakes. Occasionally a heavy spring rainfall may alter the character of the run-off, but even then there is never any question of spring flood damage to land or property — the river s are swollen rather than in flood. Critical conditions can arise however on the Saint-François following storm rains and rapid run-off (impermeability and steep slopes). The water rises rapidly, but the fall extends over a week. These floods are more severe than in spring, but damage is still minimal, the lakes in fact store 50% of the surface run-off and in the case of certain tributaries, 75%. Furthermore, the maximum specific discharge is not more than 20 cu. ft/sec/sq. m. for the regulated tributaries (Magog, Massawippï) compared with 80 or more for those that are not. Through the regulating influence of the main tributaries and that of the hydro-electric power dams on the Saint-François itself], the regime of the river is one of the most serene in Southern Québec.


2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Hua Zheng ◽  
Junhao Liu ◽  
Shiqiang Duan

Flutter tests are conducted primarily for the purpose of modal parameter estimation and flutter boundary prediction, the accuracy of which is severely affected by the acquired data quality, structural modal density, and nonstationary conditions. An improved Hilbert-Huang Transform (HHT) algorithm is presented in this paper which mitigates the typical mode mixing effect via modulation. The algorithm is validated by theory, by numerical simulation, and per actual flight flutter test data. The results show that the proposed method could extract the flutter model parameters and predict the flutter speed more accurately, which is feasible for the current flutter test data processing.


Author(s):  

The article considers main physical and geographical factors affecting the runoff, spring flood of rivers in the Arpa River basin, and analyzes the regularities of their spacetime distribution. The authors have obtained correlation relationship between the values of the flood runoff layer, the mean module maximum runoff and weighted average height of the catchment area of the Arpa River, between the mean annual maximum runoff module for the period floods and catchment areas of rivers. These dependencies can be used for preliminary estimates of the spring flood runoff of unexplored rivers of the territory under consideration. A close correlation between the values of the annual runoff and the runoff of the spring flood in the section of the Arpa River – Dzhermuk has been also revealed. It can be used for forecasting the annual flow.


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