Flow Impingement, Snake River, Wyoming. (Flood Control Structures Research Program)

1993 ◽  
Author(s):  
Stephen T. Maynord
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.


1976 ◽  
Vol 13 (10) ◽  
pp. 1358-1373 ◽  
Author(s):  
Andrew J. Pearce

Near-complete destruction of vegetation over 125 km2 near Sudbury, Ontario has increased denudation rates by two orders of magnitude and caused substantial changes in hydrologic regime. Denudation by channeled and unchanneled flow, measured with erosion pins on small plots (2–1000 m2) and a small drainage basin (0.09 km2), averaged 6000 m3/km2 (maximum 24 700 m3/km2) during summer and fall in 1971 and 1972. Maximum denudation occurred during late August to October. Snowmelt runoff in 1972 yielded 1000 m3/km2 of sediment. The weighted average denudation rate, including rates of bedrock disintegration (60–170 m3/km2/y; mean 120 m3/km2/y) is 3700 m3/km2/y.Runoff coefficients average 0.88 for events with return periods between 2 and 10 years; 25% of the May–October rainfall runs off as Hortonian overland flow. Estimated sedimentation rates for three flood-control structures indicate 25% storage depletion over a 50 year period; the return period of floods then able to be retained is reduced to 50 years, compared to the design parameters of 100 year 6 h rainfall (smaller structures) and 100–200 year 12 h rainfall, 6 h P.M.P. (largest structure).


2017 ◽  
Author(s):  
Joseph Dunbar ◽  
Gustavo Galan-Comas ◽  
Lucas Walshire ◽  
Ronald Wahl ◽  
Donald Yule ◽  
...  

2013 ◽  
Vol 10 (4) ◽  
pp. 4515-4536 ◽  
Author(s):  
G. Di Baldassarre ◽  
A. Viglione ◽  
G. Carr ◽  
L. Kuil ◽  
J. L. Salinas ◽  
...  

Abstract. Over history, humankind has tended to settle near streams because of the role of rivers as transportation corridors and the fertility of riparian areas. However, human settlements in floodplains have been threatened by the risk of flooding. Possible responses have been to resettle away and/or modify the river system by building flood control structures. This has led to a complex web of interactions and feedback mechanisms between hydrological and social processes in settled floodplains. This paper is an attempt to conceptualise these interplays for hypothetical human-flood systems. We develop a simple, dynamic model to represent the interactions and feedback loops between hydrological and social processes. The model is then used to explore the dynamics of the human-flood system and the effect of changing individual characteristics, including external forcing such as technological development. The results show that the conceptual model is able to reproduce reciprocal effects between floods and people as well as the emergence of typical patterns. For instance, when levees are built or raised to protect floodplain areas, their presence not only reduces the frequency of flooding, but also exacerbates high water levels. Then, because of this exacerbation, higher flood protection levels are required by the society. As a result, more and more flooding events are avoided, but rare and catastrophic events take place.


2013 ◽  
Vol 17 (8) ◽  
pp. 3295-3303 ◽  
Author(s):  
G. Di Baldassarre ◽  
A. Viglione ◽  
G. Carr ◽  
L. Kuil ◽  
J. L. Salinas ◽  
...  

Abstract. Over history, humankind has tended to settle near streams because of the role of rivers as transportation corridors and the fertility of riparian areas. However, human settlements in floodplains have been threatened by the risk of flooding. Possible responses have been to resettle away and/or modify the river system by building flood control structures. This has led to a complex web of interactions and feedback mechanisms between hydrological and social processes in settled floodplains. This paper is an attempt to conceptualise these interplays for hypothetical human-flood systems. We develop a simple, dynamic model to represent the interactions and feedback loops between hydrological and social processes. The model is then used to explore the dynamics of the human-flood system and the effect of changing individual characteristics, including external forcing such as technological development. The results show that the conceptual model is able to reproduce reciprocal effects between floods and people as well as the emergence of typical patterns. For instance, when levees are built or raised to protect floodplain areas, their presence not only reduces the frequency of flooding, but also exacerbates high water levels. Then, because of this exacerbation, higher flood protection levels are required by society. As a result, more and more flooding events are avoided, but rare and catastrophic events take place.


Author(s):  
Mohammad Sharifi ◽  
Mohammad Reza Majdzadeh Tabatabai ◽  
Seyed Hossein Ghoreishi Najafabadi

Abstract Rivers are usually exposed to floods that cause significant human and financial loss, for which structures are considered in the rivers for preventing floods and reducing damage. In this way, it is necessary to acquire design discharge for building these structures. The case study was conducted on the Tar River of Ghazi Station in Tehran Province, which originates from 1 km west of Tar Lake in 13 km east of Damavand. The Tar River is one of the tributaries of Damavand River. In this study, the cross section of the river was first measured through surveying and existing maps. The design discharge of flood control structures was designed using the methods described in this study. Moreover, the stage-discharge table was used to obtain the Manning roughness coefficient. The effective discharge was calculated using the sediment rating curve and sediment frequency histogram, while the bankfull discharge was derived from the return period of 17 years discharge record and fitting of Gumbel distribution to the data. The results indicated that the average of dominant, effective, and bankfull discharges could be the appropriate design discharge for the river, as their values are significantly close to each other. However, there is no need to use flood control structures in this river, due to the occurrence of medium frequent flood events in the river.


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