Numerical Evaluation of Seepage Monitoring in Embankment Dams Utilizing Temperature Method

Dams are an important part of this nation's infrastructure. When populations at risk are located close to a dam, it is important to accurately predict the breach outflow hydrograph and its timing relative to events in the failure process that could trigger the start of evacuation efforts. Surge waves resulting from dam breaks have been responsible for numerous losses of life. Sudden reservoir drawdown caused by partial breach of a dam can create a surge within the reservoir. Positive and negative surges are generally observed in open channels. Positive surges that occur due to tidal origins are referred to as tidal bores. They also occur upstream of a control structure that is opened rapidly or the failure time is very low. For a stationary observer the negative surge appears to be a gentle lowering of the free surface. Methods of seepage monitoring and assessment can play a critical role in the field of embankment dams' safety. Increased seepage could simultaneously be occurred with internal erosion. Internal erosion is known as one of the main reasons of dam failure, causes increased seepage due to loss of fine grain sizes. As a result, seepage monitoring system is substantial part of embankment dams monitoring system. Gradually, internal erosion progresses in the dam and is difficult to be detected by conventional methods. Many of seepage measurement systems are not sensitive enough to detect small variations in seepage flow. Measurement of temperature is one of the most affordable methods in embankment dams seepage monitoring. Monitoring and examination of dams could be carried out benefiting built-in accessories, borehole method, non-destructive test methods and etc. In this research, different methods of seepage monitoring in embankment dams are investigated concentrating on temperature method. Among others, temperature is one of the most important physical parameters that depend directly on internal erosion. Thermometry therefore provides a useful measure to recognize seepage in primary state. There are various methods based on temperature measurement and analysis in embankment dams that are assessed in this paper. For this purpose, the methods including lag-time, amplitude, numerical, and optical fiber sensors methods are evaluated and compared relevantly, for the sake of recognition of the most recent and preferable method. A system based on optical fiber sensors is known as the most recent, powerful and economized method in monitoring of hydraulic structures. This paper provides the Parametric Models methods and numerical model such as McCormack Explicit scheme and Pressman Implicit scheme using Hec-Ras to simulate dam break furthermore it used to predict breach outflow hydrographs. Unsteady flow modeling is often used in dam breach analysis due to the need to obtain more detailed or accurate results. The breach parameters will directly and substantially affect the estimate of the flows. Due to this illustrate the failure time is very low, as a result the negative surge occurs, However De St. Venant differential equations are not valid in the neighborhood of the surge. In order to evaluate the effective of negative wave on the outflow hydrograph.