Dam break flows could lead to serve flooding with catastrophic consequences, such as damage to properties and loss of human life. Therefore, Dam break flows have been the subject of scientific and technical research for many hydraulic scientists and engineering. The mitigation of the impacts to the greatest possible degree requires modelling of the flood with sufficient detail so as to capture both the spatial and temporal evolutions of the flood event (Jorgenson, 2004), as well of the velocity field. The selection of an appropriate model to correctly simulate dam-break flood routing is therefore an essential step. Traditionally, one and two-dimensional models have been used to model dam break flooding, but these models are limited in their ability to capture the flood spatial extent, in terms of flow depth and velocity and timing of flood arrival and recession, with any degree of detail. The development in the last years has led to several numerical models aimed at solving the so-called dam break problem (Soarez Frazao, 2002). The Concerted Action on Dam Break Modelling (CADAM) project (Morris,1998), has been set in motion by the European Union to investigate current methods and use in simulating and predicting the effects of dam failures. The obtained results show that shallow water scheme is reasonably suitable for the representation of free surface sharp transient (Wang et al., 2000) and the authors concluded that shallow water methods agree satisfactorily with experimental results (Alcrudo, 1998). Earlier studies were primarily based on analytical solutions for idealist conditions. For example, Stoker developed an analytical solution to predict dam break flows in an idealisted channel, in which the bed slope was assumed to be zero and... ... middle of paper ... ...yperbolic problems. Afshar and Shobeyri studied the effect of irregularity of domain discretization on the performance of the CDLS method for the solution of convection-dominated problems. They concluded that their proposed CDLS method was able to produce highly accurate results for hyperbolic problems even on highly irregular distribution of nodes. This method was later used for simulation of free surface problems by Shobeyri and Afshar. They employed a priori error estimator to improve the efficiency of simulating free surface flows problems with CDLS method. In this paper schemes was examined for the solution of the one dimensional homogeneous shallow water wave equations using the meshless associated with approximate collocated discrete least square (CDLSM) method. Then a well-known analytical solution to the dam-break problem was used to assess the performance.
Floods can be a very dangerous natural disaster because a flood has the power to move cars, buildings, and cause massive damage to life and property. Even the small floods that are only 30 centimetres or so can do massive damage to houses and if the
A major flood on any river is both a long-term and a short-term event, particularly any river basin where human influence has exerted "control" over the ri...
The one feature common to the Hoover Dam, The Mississippi river and the three gorges dam is that they all tried to control nature’s swings, specifically in the form of flooding. Before the Hoover dam was built, the Colorado river “used to flood spectacularly…but after 1900 the Colorado provoked a vehement response” (Pg 177). The response was simple, but large. The U.S. built several large dams, including the Hoover dam, on the Colorado to decrease its flooding and increase power and irrigation. Unfortunately, just as human control of the Colorado’s flooding increased, its organisms and habitats were detrimentally influenced, and the water became more and more salinated.
The Oroville dam is a rock fill embankment dam, which means, a water barrier that is made with certain materials so that it isn’t prone to erosion or deterioration. Because the material is so heavy due to the need for a secure dam, , it creates a much stronger barrier and base to its foundation. A study was done to see if a rock fill dam is the most stable type of dam to hold the amount of water it is expected to. The study tested different types of dams stability compared to the stability of a rock fill, and ultimately found that the rock fill is completely acceptable and safe (Lei). The Feather River is the only river to feed into the dam, filling it to its total capacity of 3,507,977 acre/ft.
Based on the events that lead to the devastating floods in Queensland and the eventual case that was brought against the engineers of the dam, there have been views from both sides of the divide as to whether or not the actions taken by the engineers were actually ethical or otherwise. We have explored this avenue and have found that both sides of the divide have good reasons to justify their actions. Firstly, we shall explore the avenue that the engineers decisions were appropriate and ethical. It can be said that the engineers did employ act utilitarianism in their decisions and actions, hence causing these decisions to be ethically correct. Act utilitarianism is essentially doing the right thing, which would benefit the majority of people, based on the situation that is currently taking place. One of the reasons that explains why the actions taken could be considered as ethically fine, was that if the dam was not opened, there would have been no other way to solve the increasing water levels in the dam. If no action was taken, there could have been seriously devastating effects, like the dam wall eroding due to water spilling over the dam wall, thus weakening the structure, or a loss of water flow control. Professor Hubert Chanson, a professor in hydraulic engineering in the University of Queensland, mentioned that the Wivenhoe Dam was actually designed as an embankment dam, hence it should not be overtopped, that is water should not be allowed to flow over the limits of the dam (Andersen 2011). Despite there being a secondary spillway, however it is recommended that spillway is not put to use, as the use of that spillway would mean that there would be a surge of water leaving the dam, and a loss of control of the water flow, w...
The river, despite many efforts, found new channels to travel to every time the engineers thought they were getting close. Kevin Fedarko describes how difficult it was for the engineers to control the river, “After an all-out campaign that had cost in excess of $3 million, the breach was finally plugged and the Colorado was forced to resume its course through the delta to the Sea of Cortes” (p. 59). He not only mentions the work done by the men, but also the expenses that went into trying to harness the power of the river for resources. The research that goes towards building and designing dams has improved tenfold over the past 50 years. In an essay written by a student attending Harvard University, the student explained the great effect the dam has had on the surrounding communities, “It was felt that a dam that could control the river would also provide hydroelectric power, eventually rendering the dam self-financing. The growth of Las Vegas and Southern California as major metropolitan centers also depended, to a large extent, on the availability of water and power… the dam possessed an epic quality that stimulated the national imagination. It was apparent that the meaning of the dam itself was beyond even that of a structure that equaled the vast landscape it inhabited. The dam, and the people who built it began controlling nature in a new and powerful way” (par. 3). The author explains how years of advancing dam technology have given the nation a “stimulated imagination” and that has brought forth many of the world’s newest technological advancements. The dam has brought many people ideas and inventions to build and grow on. Dams are the gateway for life-changing tools for harnessing the power that we can get from renewable resources like water and wind that then eliminate harmful chemicals and debris for
The dam itself spanned a gap of 918 feet across the valley and was 72 feet high. The primary materials used for the dam were rock and other earth. The dam started as 10 feet thick at the top of the structure and expanded to 220 feet at the base (NPS). As you can see in the image below of the dam there is a culvert that runs under the dam that was used to discharge water in the South Fork Creek that was then sent to a local canal. The flow of water was controlled by five 2ft diameter cast iron valves that were located in the tower to the left of the structure. In the event of an emergency were the culvert couldn't handle a large quantity of water an 85 ft wide spill-way was cut through the solid rock of the hillside near the eastern end of the dam (Jackson, Donald Dale).
In the beginning of the construction of the Three Gorges Dam, there were several problems. There were several protestors and opinions about the dam before the Three Gorges Dam project was even started.1 China has had history of several dam failures in the mid-1970s that were responsible for thousands of deaths. The three gorges (Xiling, Wu, and Qutang) have scenery that is a tourist attraction.2 The dam was going to be a little over 600 feet tall, 7500 feet wide, and hold over 97 trillion gallons of water. Because of all of the population increase, China started using coal power plants1 and shipping, which causes acid rain over the region making the Yangtze River is one of the most polluted rivers in the world.4 It does not help that the Yangtze River runs right through Chinas industrial heartland. Using the river to transport their goods to other parts or China adds to the pollution.2 Pollution from mines, hospitals, and garbage dumping is another big problem for the river because the pollution is building up around the dam.1 With the Three Gorges Dam will come landslides because of the rising water tables and the large slopes with unstable soil from local farming causing more sediment being added to the river.3 And because the dam lies on a fault line there will also be an escalation of earthquakes. There is a huge decrease in sediment discharge; which caused a 90% sediment load into thousands of other reservoirs. Before the dam was operational, it was retaining water and sediments.4 The water levels were rising faster than anyone expected, therefore, the finish date had to be moved up.1 Scientists even projected that 70% of sediment discharge would be trapped for the first two decades and 44% would be store...
A river or “stream, ribbons of water confined to channels, or troughs, cut into the land,” (Marshak, 2009) is formed from a drainage network or “the array of interconnecting streams” that form tributaries. (Marshak, 2009). The amount of water that flows down a stream is its discharge. The discharge measurement takes the width and depths or cross sectional area of a river as well as the downstream velocity to get a numeric value for amount of water moving down stream. (Marshak, 2009)
Each system tract is bound by a surface, between the lowstand and transgressive systems tract we find the transgressive surface. The transgressive and highstand systems tracts end and begin respectively by the the maximum flooding surface. The highstand and falling-stage systems tracts are separated by the basal surface of forced regression.
Many different culvert options are available for stream crossings comprising of a no slope design, a hydraulic design, or a stream simulation design. When considering any one of these designs many concerns need to be addressed including; direct habitat loss, water quality, upstream and downstream channel impacts, ecological connectivity, construction impacts, and possible failure. Direct habitat loss can occur if the culvert is installed in current fish spawns, growth areas, feeding areas, or migration areas. Water quality is effected during construction of the culvert as dirt particles or other foreign material enters the stream. Upstream and downstream channels are affected if flow rates are changed by water depth or channel depth and can further effect stream qualitie...
The issue of dam building is an environment one as the impacts on the environment are high but the reasons for building dams are for economic and social reasons, linked to continual water supply to produce food for a growing population. Particularly during the Industrial Revolution was there an increase in the amount of water required for industry and agriculture (Asit K. Biswas & Cecilia Tortajada 2001).
UNITED STATES DEPARTMENT OF THE INTERIOR AND BUREAU OF RECLAMATION. (1985) Hoover Dam. Washingto, D.C., pp. 56.
A Flood Hydrograph and the Factors That Affect its Form A flood hydrograph is a graph of two axis, 'discharge' and 'time'. Plotted on the graph is the amount of discharge over a period of time. By looking at a hydrograph, a lot of information and data can be gathered about the river, the precipitation, the surrounding area and vegetation etc. The gradient, height and length of a line can tell you a lot of this information. There are many different factors that can affect the appearance and shape of a hydrograph.
The paragraphs below will prove that the construction and presence of dams always has and will continue to leave devastating effects on the environment around them. Firstly, to understand the thesis people must know what dams are. A dam is a barrier built across a water course to hold back or control water flow. Dams are classified as either storage, diversion or detention. As you could probably notice from it's name, storage dams are created to collect or hold water for periods of time when there is a surplus supply.