Flood waves

Unsteady flow also includes such topics as oscillations in connected reservoirs and in U tubes and such phenomena as tidal motion and flood waves. Likewise, the field of machinery regulation by servomechanisms is intimately connected with unsteady motion. However, all these topics are considered to be beyond the scope of the present text. 

James Alexander Seddon was edueated as a eivil engineer. He soon joined as member the Engineers Club of Saint Louis and from 1895 was US assistant engineer. He was stationed at Kansas City MO and there was in charge of works on Missouri River. Few details on his life are known, despite his name has been preserved until today, relating to unsteady flow in rivers, and the propagation of flood waves. 

Talbot, A.N., Grover, A. (1893). Discussion of Flood waves in sewers. Trans. ASCE 28 199-204. 

Chapters 15 and 16 discuss accidents resulting from earthquakes and tornadoes. Protection against floods has to be considered in the choice and the improvement of a site usually, no possible flood water is permitted to reach the level of the station, whose elevation is frequently raised by an embankment. Obviously, the choice of a site includes the study of the possible collapse of nearby dams and of the consequent flood waves. 

Verification of the soil strength should not, however, neglect the foundation soil bearing capacity for higher loads caused by an earthquake, the resistance of slopes, soil support walls or of other works of interest for safety, also considering potentially induced indirect effects, such as flood waves in streams due to the failure of dams (Hansen, 1970 Meyerhof, 1951 Janbu, 1957 Morgenstern and Price, 1965 Sarma, 1975, 1981 Espinoza, Bourdeau and Muhunthan, 1994). 

Risk perception Forest fires Road accid Heat Floods waves Dam rupture... 

Consideration of the movement of water on a shorter time scale is bnilt around the hydrologic cycle, which provides a conceptual picture of the short-term dynamics of the system. Time scale is an important factor. Surface water dynamics have time scales of hours and days, while subsurface (groundwater) dynamics have time scales of months and years. For example, flood waves move down rivers at velocities of several km/hr while groundwater surface elevations may change by a few meters during the course of an irrigation season and tens of meters during periods of continued overdraft. 

Water is represented as Flood, Wave, Deluge, Influx, Pour(into), Tide and Swamp. As in Human Tide Labour Would Let In (The Sun, 4 April 1992). 

It is recognized that floods originating from dam failures could be increased by flood waves due to landshdes into rivers and reservoirs, which could result from severe precipitation. Floods caused by dam failures should generally be combined with an appropriate flood due to other causes (see below) to obtain the controlhng flood. The appropriate coincident wind wave activity (wave set-up and wave runup) should be superimposed on the flood still water level that has been determined. 

A series of rainstorms filled the reservoir quickly in late fall of 1959. At 9 14 p.m. on December 2,1959, the Malpasset dam failed explosively, giving rise to a flooding wave more than 40 m high. Only a little portion of the arch of the dam still remained in its original position. Four hundred twenty one deaths were attributed to the failme. The failed dam is shown in Fig. 3.3. 

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