Mosul Dam, NW Iraq: Is a Safe Dam??

Mosul Dam is located in the northwestern part of Iraq impounding the Tigris River; about 60 km north of Mosul city. This project is multipurpose project; to provide water for irrigation, flood control and hydropower generation. The dam is 113 m high and 3650 m long including the spillway. The dam is earth fill type with a mud core. The dam was designed to impound 11.11 km3 because it is based and underlain by gypsum beds alternated with limestone and marl. Therefore, it is planned to use continuous grouting to fill the karst caverns. The used quantity exceeded 95000 tons of solid grouting materials since 1986 up to 2014. After all, is the dam safe? The details are given in the current article.

Fluctuation Effect of Reservoir Water Level on the Seepage of Earth-Fill Dam

Lots of dam failures are the result of uncontrolled seepage. The collapse of the Situ Gintung Dam in Tangerang, Banten-Indonesia in 2009 due to heavy rains caused the dam structure to collapse. This is due to increased pore water pressure in the landfill. To anticipate collapse due to uncontrolled seepage, it is necessary to monitor it based on the behavior of changes in rainfall and reservoir water levels. Seepage within the dam body is often monitored using instrumentation tools such as standpipe piezometer (standpipe piezometer) or electric piezometer. But often the piezometer cannot work properly because it is clogged, so it cannot monitor the condition of the seepage. Other instrumentations such as V-Notch are also used to measure seepage discharge. This study aims to determine the behavior of changes in the reservoir water level caused by changes in rainfall and its effect on body seepage of the earth-fill Type dam. By knowing the phenomenon of the behavior of the relationship between reservoir water infiltration and rainfall, it will obtain information on rainfall that endangers the dam which will affect the downstream. In this study, a case study of the Selorejo Dam was taken which has a large enough reservoir capacity of about 31 million m3 which is included in the Brantas River Basin. The results showed that 5 piezometers devices were damaged (SL 1, SL 2, SL 4, SL 6, and SL 7) where they could not read the phreatic water level properly, and 2 piezometers were less sensitive to reading fluctuations in reservoir water levels. namely SL 10 and SL 11 which showed R2 values of 29.78% and 39.4%, respectively. While the maximum seepage discharge is recorded at 1474 liters/minute, this is still below the critical discharge of 1630 liters/minute allowed for this dam, but this needs to be a concern, especially the discharge from toe drain from the left side seepage and C-area which is the leakage from the left support pedestal also contributes a larger discharge than other observation points.

Analysis and Estimation of Seepage Through Earth Dams with Internal Cut Off

The study of seepage through earth-fill dams is very important for the constructed dams to ensure that the control of seepage is sufficient for the safe and sustainable operation of the dam. It is also important in the design and construction of new dams to ensure that the seepage through and under the dam will be well controlled. Construction horizontal, inclined, trapezoidal or pipe filters one of the dam protection methods. Cut off also can be constructed to minimize seepage discharge directed to the downstream face of the dam. Seepage through an earth dam with internal cut off is experimentally studied in the laboratory of Irrigation Engineering and Hydraulics Department, Faculty of Engineering, Alexandria University, Egypt on a Hele-Shaw model. Also, using computer program SEEP/W (which is a sub-program of Geo-Studio). The experimental and numerical analyses of seepage through earth-fill dam with internal cut off is conducted. Results from solutions are compared with each other.

EARTH FILL INCREASES EFFICACY AND LONGEVITY OF λ-CYHALOTHRIN RESIDUAL INSECTCIDE TREATMENT OF HESCO® BLAST WALL GEOTEXTILE

The prevention of vector-borne disease to protect the health and readiness of United States forces in the field continues to be a high priority for the US Department of Defense. Previous studies have demonstrated that the risk of human contact with disease-vector mosquitoes and other biting flies can be reduced by applying an insecticide to perimeters of military materials such as camouflage netting or HESCO blast protection wall geotextile already in place around troops in the field. In this study we investigated whether residual pesticide efficacy will persist in the presence of earth fill that is required for operational use of HESCOs, using a warm temperate field site in north Florida. Results from laboratory bioassays measuring mosquito mortality and field collections of natural mosquito populations indicated superior efficacy and greater longevity of pesticide treated geotextile exposed to soil fill. These findings not only support immediate implementation of this technique in US military field scenarios, but also provide evidence that HESCO technology currently used in natural disaster flood control could be leveraged to protect civilian personnel from emerging floodwater mosquitoes.

Influence of speed of filling and draw-off to the filtration regime of Earth-fill dam

To use and manage water resources and carry out protection measures from the destructive effect of water flow, water reservoir hydrosystem construction has greatly developed. The article presents the results of field studies to determine unsteady filtration in the Earth-fill dam core. In the research process, static data from literature review, field study data, and theoretical processing of research results were used. Numerical data processing was carried out with methods of mathematical statistics, and the graphical part was done using Microsoft Excel. Calculations were carried out for phreatic line curve in the core of Earth-fill dam under unsteady filtration for various velocities of reservoir draw-off and water yield coefficient. At the same time, it has been established that the increase of velocity and time of water reservoir draw-off leads to the increase of filtration pressure, and the decrease of water yield factor leads to the decrease of filtration pressure. The increase of filtration pressure, in turn, contributes to the increase of the intensity of unsteady filtration of the Earth-fill dam core.

Filtration reliability and safety of earth-fill dam

The study of the reliability and safety of the constructed earth-fill dams and the comparison with their design and calculated data makes it possible to improve the structures and methods of the calculation substantiation of these structures. This work aims to study the filtration reliability and safety of the earth-fill dam of the Channel water reservoir of the Tuyamuyun hydroelectric complex (THC) on the Amu Darya River, which was put into exploitation in 1984. Field studies were carried out according to the traditional method using results of control and measuring equipment (CME) embedded in the body of the dam. The water levels of the upper and lower reaches, piezometers, and drainage water flow were measured. The maximum water levels upstream of 130.00 were observed in July-August and November 2017, and the minimum of 117.50 at the end of March. The water levels downstream depend on the value of the discharge through the hydrosystem. The maximum level downstream for 2017 was 112.55 m (01.06.2017) with a flow rate of 2000 m3/s. The minimum level downstream of 109.15 m was observed on November 29, 2017, when the discharge into the downstream through the hydroelectric complex was 260 m3/s. A tendency to an increase in the level of the bottom downstream was found. Filling and depletion graphs of the Channel water reservoir have been built, from which it is found that they reached 2.00 m/day, and 1.60 m/day, respectively. This is 4 and 1.6 times more than the standard 0.5 m/day and 1.0 m/day. Of the 53 piezometers, 34 are working conditions; the rest do not work, require flushing. Graphs of water level changes in piezometers show that they change with an average 15-20 day delay in the water level in the Channel water reservoir. In general, the natural depression curve is below the design one. The maximum filtration flow rate was 63.3 l/s at a water level in the upper pool of 129.00.