Protection Dams Research Articles

Enhancement of Air-Entrained Grout-Enriched Vibrated Cemented Sand, Gravel and Rock (GECSGR) for Improving Frost and Thawing Resistance in CSGR Dams.

Cemented Sand, Gravel, and Rock (CSGR) dams have traditionally used either Conventional Vibrated Concrete (CVC) or Grout-Enriched Roller Compacted Concrete (GERCC) for protective and seepage control layers in low- to medium-height dams. However, these methods are complex, prone to interference, and uneconomical due to significant differences in the expansion coefficient, elastic modulus, and hydration heat parameters among CSGR, CVC, and GERCC. This complexity complicates quality control during construction, leading to the development of Grout-Enriched Vibrated Cemented Sand, Gravel, and Rock (GECSGR) as an alternative. Despite its potential, GECSGR has limited use due to concerns about freeze-thaw resistance. This project addresses these concerns by developing an air-entrained GECSGR grout formulation and construction technique. The study follows a five-phase approach: mix proportioning of C1806 CSGR; optimization of the grout formulation; determination of grout addition rate; evaluation of small-scale lab samples of GECSGR; and field application. The results indicate that combining 8-12% of 223 kg/m3 cement grout with 2-2.23 kg/m3 of admixtures, mud content of 15%, a marsh time of 26-31 s. and a water/cement ratio of 0.5-0.6 with the C1806 parent CSGR mixture achieved a post-vibration in situ air content of 4-6%, excellent freeze-thaw resistance (F300: mass loss <5% or initial dynamic modulus ≥60%), and permeability resistance (W12: permeability coefficient of 0.13 × 10-10 m/s). The development of a 2-in-1 slurry addition and vibration equipment eliminated performance risks and enhanced efficiency in field applications, such as the conversion of the C1804 CSGR mixture into air-entrained GECSGR grade C9015W6F50 for the 2.76 km Qianwei protection dam. Economic analysis revealed that the unit cost of GECSGR production is 18.3% and 6.33% less than CVC and GERCC, respectively, marking a significant advancement in sustainable cement-based composite materials in the dam industry.

Modeling the successive failure of complex dams systems: A necessity in the light of climatic shifts in extreme storms

This study investigates the effect of extreme storms on the safety of flood protection dams within complex schemes. A modeling methodology is developed using HEC-RAS 2D and presented on an illustrative case, where nine scenarios are simulated. The impact of climatic shifts on extreme storms and dams’ safety is highlighted. The results showed that, despite multi-reservoir systems can be efficient in flood protection against their design storms, they can cause catastrophic damage when subjected to extreme events that have become evident nowadays due to climatic shifts. This is attributed to the successive failure of the water storage structures in a progressive (“domino-like”) manner. The consequences of such breaches can significantly multiply the hazards. These findings can be linked to storm Daniel that occurred at Wadi Derna in Libya and caused two successive dam breaches, leaving a tragedy. The proposed modeling methodology can be useful for designers in evaluating complex scenarios.

Technogenic transformation of the Lena River floodplain near Yakutsk and assessment of landscape disturbance

The Tuymaada Valley located in the Yakutsk region represents the most developed region within the Lena River fllodplain. Landscape studies conducted here between 2016 and 2022 revealed a significant level of technogenic transformation: 30.4 % of its sites showed a high and moderate degree of disturbance. The primary driver of landscape development was the transformation of forested areas into meadows due to centuries of grazing in the floodplain. The current trend in evolution involves replacing agricultural stows with residential ones, leading to an increase in mechanical disturbances to the landscape structure. Water protection dams have removed significant areas of the left bank floodplain from the flood zone. Consequently, some of its stows become swamped, while others transform into dry wastelands with low-value steppe meadows. Currently, at the investment justification stage, the issue of providing comprehensive protection for the entire left bank of the Tuymaada valley from the adverse effects of floods and inundations is under consideration. For its continued growth, it is essential to implement not just protective measures but also environmental and improvement measures for both existing and new urban, rural, and economic-technical zones on the developing technogenic terrace.

Evaluation of Probable Maximum Precipitation (PMP) for West Virginia to Predict Current and Future PMP

Probable maximum precipitation (PMP) is essential for dam design criteria. West Virginia Department of Environmental Protection Dam Safety utilizes the 6-hr, 10-mi2 (26-km2) PMP established by Hydrometeorological Report 51 based on the analysis of extreme rainfall. These PMP are outdated because there have been unaccounted for extreme rainfall events that have occurred since 1978. In addition, a zone of uncertainty around the Appalachian Mountains exists, including West Virginia (WV). The objective of this research was to determine the PMP throughout WV by studying the area of uncertainty and consider rising dew points to predict future PMP. This study created an updated PMP map of WV, focusing on the maximization of the 1942 Smethport, PA storm. A watershed-specific analysis was conducted at all dams in the state with an approximate watershed area of 10-mi2 (26-km2). Current PMP estimations and projections for 2100 were determined. Iso-lines were determined to develop the new updated PMP map for WV that displays current and future PMP estimations. Results suggest that the greatest values of PMP occur in the western region of the state; lowest values of PMP occur in the south-eastern part of the state. The Smethport, PA storm (1942) was considered the governing storm for the entire state; however, it may not apply to the eastern panhandle and Potomac highlands. These regions should be considered for additional analysis. The updated PMP map will be a resource for those involved in dam inspection, repair, design, and modification.

Challenges of ecological and technical dam maintenance using the example of the Marchfeld protective dam (Lower Austria)

Challenges of ecological and technical dam maintenance using the example of the Marchfeld protective dam (Lower Austria)

Justification of Technological and Design Parameters of Polder Drainage Systems by an Optimization Approach

Abstract A system optimization method was used, which consists in the consistent justification of optimal technological and constructive solutions and parameters of drainage polder systems during the development of their projects. This is done in compliance with modern economic and environmental requirements according to criteria and models for di erent levels of management decision-making over time (project, planned operation). Based on the performed relevant predictive and optimization calculations for the conditions of the real object, the following three tasks have been accomplished. (1) The optimal pump module at the stage of operation for the existing polder drainage system has been substantiated. (2) The design of the pumping unit and the parameters of its components during the reconstruction of the polder drainage system have been improved. This made it possible to reduce the load on the pumping equipment, the duration of its operation, and the cost of electricity by 20–40%, depending on the water level of the year. The improvement was carried out by the diversion of the corresponding part of the surface runo with additionally introduced gravity elements in the form of a puncture in the body of the protective dam and a siphon intake. (3) We have substantiated the optimal water regulation technology for the existing polder drainage system in modern and forecast weather and climate conditions, which will ensure the maintenance of the necessary water-air regime of the drained soils in di erent phases of the growing season of agricultural crops. This will make it possible, on demand, to increase the energy and general environmental and economic e ciency during their creation and functioning of the polder drainage system in accordance with modern changing conditions.

Analyzing stability of protective structures as the elements of geotechnical tailing pond safety

Purpose is the assessment of soil retaining wall stability to ensure geotechnical safety during the radioactive waste tailing pond closure and further recultivation (or rehabilitation) in Kamianske town (Ukraine). Methods. Geomechanical stability of the protective structure has been assessed relying upon the analysis of geological-hydrogeological, engineering-geological, and geotechnical conditions of the certain tailing pond area using a deformation elastic-plastic model of a medium implemented on the basis of finite-element method. For the purpose, the dam slopes have been detalized taking into consideration their geometry as well as changes in vertical section of rock material characteristics in accordance with the earlier geophysical studies; exploration drilling; and engineering-geological surveys. Findings. Stability coefficients of protective tailing pond dam have been identified within the typical areas of a hydraulic structure; it provides high reliability and representativeness of the whole structure health in time as well as under various conditions of the industrial waste water saturation. It has been defined that the stability coefficients varies from ks = 1.372 to 4.758. Comparison of the indicators between 2022 and 2016 demonstrates a tendency of the slope stability coefficient decrease due to water saturation and groundwater level rise. Nevertheless, design characteristics of the structure make it possible to ensure satisfactory a stability coefficient along the whole dam length being 1.13 times higher than the standard one (i.e. ks = 1.250). Originality. The dependence of the tailing pond protective dam stability upon a water supply degree at the forecasted groundwater level rise at the expense of atmospheric and melt water ingress to the tailing pond has been defined. The danger of complete radioactive waste water saturation is a significant reduction in the stability coefficient of the protective structure, which can be supported by predictive modelling data. If strength parameters of a dam material decline for the most critical area then the strength coefficient decreases starting from 1.532 in terms of the current groundwater level down to 1.372 as for the forecasted dam water supply. The figure is more than 10% of its initial stability. Practical implications. The obtained results substantiate the necessity; moreover, they are of practical value while improving hydrological, hydrogeological, and geotechnical monitoring of the analyzed tailing pond to ensure its radiation safety under different conditions of further behaviour during closure, recultivation, or rehabilitation.

Simulation of ash dump embankment stability

Ash and slag materials are removed from boiler rooms of CHP “Combined Heat and Power Plant” (Teploelektrotsentral’) by hydraulic transport and disposed in ash dumps. These are specially organized areas encircled by protective dams depending on the relief either along the entire perimeter or only in certain low-lying areas. The dams of hydraulic structures must provide stability to the whole structure against the following factors: shear; stability of slopes against sliding; filtration resistance of a dam body soils; reliable slope protection against possible failure due to atmospheric precipitation; as well as against wave action of water (within a settling pond); sufficient excess of dam crest over water level of a pond, etc. The study focuse on the design of ash and slag dump embankment (for storage of the ash and slag removed from the boiler rooms of Karaganda CHP by hydraulic transport). Ash dump design requires a broad range of problems to be solved. These include determination of location, design features and type of embankment, area of the basin and volume of the stored waste, strength of the embankment structures, etc. In order to assess the condition of the ash dump design, the stability of the facility embankment slopes for different combinations of loads, the conditions of possible watering of the dams, the presence of “geomembrane”, and pore pressure need to be analysed. A software program based on the finite element method allows simulation of ground (soil) conditions based on the strength and strain characteristics of the dam body filling soils and the base soils. Safety factors of the outer (downstream) slopes of hydraulic structures is determined taking into account the category and design of a structure, type of base (foundation), criticality of the design process stage, and other factors on the basis of conditions that ensure the prevention of the onset of limit states. The most critical and characteristic cross-sections across the perimeter of the ash dump embankment were selected for the computations, based on the analysis of the designed hydraulic structure base lithological composition. According to the computations performed, the outer slopes of the embankment at the paths of wells No. 373-19, No. 381-19, characteristic of almost the entire length of the embankment, are stable for different combinations of loads.

A scaling law for the length of granular jumps down smooth inclines

Granular jumps commonly develop during granular flows over complex topographies or when hitting retaining structures. While this process has been well-studied for hydraulic flows, in granular flows such jumps remain to be fully explored, given the role of interparticle friction. Predicting the length of granular jumps is a challenging question, relevant to the design of protection dams against avalanches. In this study, we investigate the canonical case of standing jumps formed in granular flows down smooth inclines using extensive numerical simulations based on the discrete element method. We consider both two- and three-dimensional configurations and vary the chute bottom friction to account for the crucial interplay between the sliding along the smooth bottom and the shearing across the granular bulk above. By doing so, we derived a robust scaling law for the jump length that is valid over a wide range of Froude numbers and takes into account the influence of the packing density. The findings have potential implications on a number of situations encountered in industry as well as problems associated with natural hazards.

SIMULATION OF INTERACTION OF WAVES WITH THE PROTECTIVE DAM OF THE DANUBE – BLACK SEA MARINE CHANNEL

Ensuring uninterrupted navigation on the Danube River and the shortest exit to the Black Sea is a priority direction for the implementation of the seventh international transport corridor, which unites the countries of Europe and Asia. For this purpose, the protection dam of the Marine channel of the Danube-Black Sea deep-sea passage was built, which was partially destroyed by storm waves and ice load. This made it necessary to carry out scientific researches in order to strengthen the operational stability of the dam and ensure its effective use. The paper presents the results of numerical and physical simulation of the interaction of waves with the protective dam of the Marine channel of the Danube-Black Sea and loads on the dam structure. Mathematical simulation was performed using the SWAN refraction and spectral model, as well as the XBeach model. Experimental research was carried out in laboratory conditions in a wave channel. The estimated distribution of the wave field near the dam under storm surge conditions was obtained and the space-time characteristics of wave pressure fluctuations on the streamlined surface of the protective dam model were determined. Integral and spectral characteristics of the pressure fluctuation field were obtained and a multi-stage form of a dam with two berms was proposed, which significantly reduced the wave load and was resistant to storm waves. The berms performed the functions of underwater breakwaters and significantly reduced the energy of the wave impact on the upper part of the dam. The optimal shape of the dam and the geometric parameters of its frontal surface were determined. It is proposed to build the seaward part of the protective dam under natural conditions with the following parameters: a lower deep-water slope with a slope of 1 : 1,5, then at a depth of 4 m a lower berm with a width of 10 m. Then make a slope with a slope of 1 : 5, and then at a depth of 2 m to install an upper berm with a width of 10 m. It is recommended to finish the protective dam of the Marine channel of the Danube-Black Sea deep-sea passage with a ridge with a slope of 1 : (3 – 3,5). The facing of the frontal part of the dam should be made of stone overburden with stones of fraction 1,2 m.

Spatio-Temporal Heterogeneity and Cumulative Ecological Impacts of Coastal Reclamation in Coastal Waters

The coastal reclamation, as one of the most extreme transformations of the ocean space by humans, still lacks scientific quantitative evaluating methods to a large extent, compared with the evolution of land use patterns. A cumulative ecological impacts of reclamation (RCEI) was established in our study based on ecological influence characteristics of different reclamation types, and the attenuation effect of reclamation on adjacent areas. It was characterized by spatio-temporal features in decades. Here, we estimated that the cumulative reclamation area in the Bohai Sea from 1985 to 2018 was 5839.5 km2. Under the influence of human activity, proportions of the industrial and urban boundary, marine construction boundaries (e.g., ports, wharves, and bridges), and protective dams were increased significantly, which led to a sharp increase of the RCEI. In addition, spatio-temporal changes of reclamation were affected by the combination of population growth, economic development, urbanization, industrialization, and marine industry development in coastal cities. These results provided an important historical reference for tracking future development of the Bohai Sea by humans and provided basic data support for the development and protection of the ocean.

A Review of Managed Aquifer Recharge Potential in the Middle East and North Africa Region with Examples from the Kingdom of Saudi Arabia and the United Arab Emirates

Groundwater extraction in most Middle East and North Africa (MENA) countries far exceeds its renewability, which ranges from 6% to 100%. Freshwater resources to support food production are very limited in this region. Future climate predictions include more consistent and longer wet periods with increasing surplus rainfall, which will enhance flood and flash flood occurrences in the MENA. Demand management of groundwater resources and managed aquifer recharge (MAR, also called groundwater replenishment, water banking, and artificial recharge, is the purposeful recharge of water to aquifers for subsequent recovery or environmental benefits) represent essential strategies to overcome the challenges associated with groundwater depletion and climate change impacts. Such strategies would enable the development of groundwater resources in the MENA region by minimizing the stress placed on these resources, as well as reducing deterioration in groundwater quality. Groundwater augmentation through recharge dams is a common practice in different countries around the globe. Most dams in the MENA region were built to enhance groundwater recharge, and even the few protection dams also act as recharge dams in one way or another. However, the operating systems of these dams are mostly dependent on the natural infiltration of the accumulated water in the reservoir area, with limited application of MAR. This review presents analyses of groundwater renewability and the effectiveness of recharge dams on groundwater recharge, as well as the potential of MAR technology. This study indicates that the recharge efficiency of dam’s ranges between 15 to 47% and is clustered more around the lower limit. Efficiency is reduced by the clogging of the reservoir bed with fine materials. Therefore, there is a need to improve the operation of dams using MAR technology.

Применение численного моделирования для расчета ветрового волнения на Крюковском водохранилище

Purpose: testing the possibilities of using the SWAN wind wave model with input characteristics according to the data of the Krasnodar (Pashkovskiy) weather station for the Kryukovskiy reservoir. Materials and methods. The studies were carried out at the Kryukovskiy reservoir, taking into account the conditions of formation of the processes of en-vironment-improving potential formation of the territory in southern Russia, which guarantees the reliability and environmental safety of the facility operation under conditions of an in-creasing risk of natural and man-made disasters on the example of the Krasnodar Territory. Field studies and field tests were carried out according to the Kuban State Agrarian University methods. When modeling the surge overwash for two different profiles (Northern and Western water barrier dams), the SWAN model data in a one-dimensional version were compared with the data obtained by SP 38.13330.2012. Results. The SWASH model provides reliable results and is an adequate alternative calculation option. Wave field data, which provides a good foundation for further study of the climatic variability of wind waves in the Kryukovskiy reservoir have been obtained. Conclusions. As a result of surge overwash modeling for two profiles under study, it was found that on average, the marks of the existing water barrier dam slope are higher than the surge in the design storm, mainly by 0.55–0.75 m, however, at PK 9 + 00 it was revealed that the slope top elevation of the Northern water pro-tection dam corresponds to the overwash mark. Therefore, it is necessary to continue research on monitoring the engineering protection of the Kryukovskiy reservoir using mathematical modeling, which confirmed the effectiveness and information content of the applicable SWAN model at a relatively low cost.

Perception of ecological aspects as part of flood protection

Modern trends in water management are more than ever inclined towards ecological solutions to avoid technical stream-channel regulation of riverbeds in the design of flood defence measures. Modifications to straighten the riverbeds that were considered in the past, removed the natural meanders of the river, increased the longitudinal slope of the riverbed, and accelerated the outflow from the threatened area. The goals of building protective dams and controlled floodplains are also limited by the negative perception of conservationists and ecologists, which leads to stagnation and discouragement from the proposals. The aim of this article is to compare the given perception of ecological aspects in different countries, how they approach them and how they are applied in studies of flood solutions. Among the ecological aspects, the following points of view will be observed: (1) options for regulation and design of flood areas, (2) duration of flooding time for the ecosystem or the landscape, (3) redefinition of riverfront in cities and (4) concept of resilience.

Evaluation and Mitigation of Flash Flood Risks in Arid Regions: A Case Study of Wadi Sudr in Egypt

Flash floods threaten the lives of people and properties in different regions around the world, especially in arid and semi-arid regions due to infrequent flood events. The current study aims to assess the geomorphological parameters of Wadi Sudr, South Sinai in Egypt to evaluate flash flood risks and provide adequate mitigation methods. This study presents an integrated method that combines geographic information system (GIS) and watershed modeling system (WMS) with HEC-HMS to visualize and assess flood events in the study area. Different morphologic parameters of the watershed were determined, including linear, areal, and relief parameters. GIS was used to analyze the satellite images and determine the characteristics of the valley to get the extension and number of stream orders in the valley, then WMS was used to estimate rainstorms and basin characteristics, as well as estimate the amount of rain that causes flooding. HEC-HMS program was used for hydrological demonstration and precipitation overflow estimation. The morphometric analysis provided a quantitative portrayal of the Wadi Sudr watershed. Wadi Sudr has 4029 streams connected with seventh order of streams spread over an area of 547.45 km2. Based on the results of morphologic and hydraulic parameters of the watershed, two locations of protection dams were suggested. A comparison between the two locations was made to select the best location based on some criteria, including storage capacity, water depth behind the dam, width and shape of the valley, and the area covered by water stored in the reservoir. The comparison between the two locations showed that the first location is more appropriate for dam construction based on the examined criteria. The valley shape in the first location is more regular than in the second. The first location provided higher storage capacity and water depth in front of the dam than the second. The area covered by water and the width of the valley is less than the second. The stability of the dam at the first site could be higher and the cost of construction could cost be less than the second due to these reasons. A comparison was made using the weighted linear combination (WLC) method, which consists of 13 criteria to determine the suitability index (SI) in order to select the best location from the proposed locations. SI proved that the first location is better than the second. The designed dam in the selected site could be cost-efficient to protect the study area from flood risks and harvesting water that can be used in different purposes. This methodology can be applied in different areas for mitigating flash flood risks.

Применение мягких гидротехнических сооружений рукавного типа при создании пожарных водоёмов и водохранилищ

Purpose. The article presents the results of theoretical and experimental studies of shear stability and hydrodynamic characteristics when interacting with water flow from hose-type soft filled waterworks. Structures of this type are applied to improve hydrological and track conditions, to construct temporary water supply reservoirs, booms for oil spills prevention. The research is aimed at determining calculated dependencies to justify parameters of hose-type filled structures when they are used as dikes and protection structures. Methods. Theoretical method has been used to obtain calculated dependences of structure shear stability. Hydrodynamic characteristics during hose structures interaction with water flow have been determined experimentally on models using similarity theory. Findings. Technique for calculating structure shear stability has been developed. Dependence has been obtained to determine stability factor, which allows setting required values for hose structures and blanket length to achieve stability factor standard value, depending on generated pressure together with soil and shell material frictional properties. Determining factors of interaction process between soft cylindrical containers and water flow have been established and dependencies have been obtained for determining coefficients of water resistance to their longitudinal and transverse displacement, depending on dimensions and velocity pattern. Dependences have been obtained for considering shallow water influence with longitudinal and transverse hose tanks under conditions of unlimited fluid and shallow water. Research application field. The research results can be used in developing methodology for calculating soft water-filled waterworks parameters for constructing fire ponds, protective dams and accumulating water reserves. The dependencies obtained for calculating water resistance to cylindrical hose-type tanks displacement in conditions of unlimited fluid and shallow water can be used when performing traction calculations and substantiating towing parameters during moving operations and deploying protective booms. Conclusions. Some issues of applying inflatable hose structures for constructing dikes and protective barriers have been studied. Research will be continued in the direction of parameters optimization, improving this type of structure construction and developing technologies for their installation.

Безопасность сооружений инженерной защиты долины реки Псекупс с учетом изменившихся во времени нагрузок и воздействий

The article uses geophysical studies of the protective dam of the valley of the river Psekups, which made it possible to clarify the boundaries of engineering-geological soil elements and determine the dynamic properties of the dam and foundation, which were used in the calculation of the barrier dam for seismic loads. It should be noted that the water level in the Krasnodar reservoir varies significantly throughout the year; its minimum value, as a rule, occurs in the autumn-winter period, and the maximum – in the spring, this signifi cantly affects the value of seepage flow through the body of the protective dam of the Krasnodar reservoir in the valley of the river Psekups and on the position of the depression curve. The main purpose of the work is to substantiate the stability of the protective dam of the Krasnodar reservoir in the valley of the river Psekups after a long operation and due to an increase in the normative seismicity of the territory. It is established that the discrepancy of one of the first approximate methods for calculating the stability of slopes according to V. Felenius with those performed in the course of the study are within the error of the initial data obtained in the field a comparison of the calculation results using a software package using the four most recognized methods in scientific, design and construction organizations in Russia – the Cray method, the Terzaghi method, the VNIIG method, the Mozhevitinov method and the method according to SP 39.13330.2012 -was carried out.

Geo-Composite Drainage Material for Hydro-Technical and Civil Engineering

The article deals with the «GP» geo-composite drainage material, which is used in hydro-technical, civil, as well as environmental, industrial and landscape construction. This material is intended for complex application, as a separating, filtering and reinforcing layer in the structures of protective dams on rivers, reservoirs, channels, an earth work of linear transport constructions (automobile and railway facilities) and other hydraulic engineering constructions. It is a combined geo-synthetic material, including a rigid geo-grid of the lattice structure and a filtering geotextile element. As a result of the carried out researches, its basic physical and mechanical characteristics have been established: tensile strength, surface density of geotextile and the material, relative elongation at maximum load, filtration coefficient normal to the material level.

Wave loads on protective dam of the Marine channel of the Danube-Black sea

The increase in freight traffic between central and northern European countries and the countries of the Black Sea coast requires an increase in shipping along the Danube River. The Danube is the seventh international transport corridor, which unites the countries of Europe and Asia. The deepening of the Bystrii estuary of the Kiliya’s delta of the Danube ensures the implementation of the transport route between the Danube and the Black Sea. The protection of the Marine channel of the Danube-Black Sea deep-sea passage from sediment during storms is provided by a protective dam. The purpose of the research is to study the peculiarities of the wave action on the fragments of an existing protective dam, determine the effective means of its protection and develop recommendations for creating a dam design that is resistant to storm loads. The results of numerical and physical simulation of wave loads on a protective dam of the Marine channel of the Danube-Black Sea deep-water passage are presented. Experimental studies were carried out to study the features of the wave action on a fragment of the dam model. The integral and spectral characteristics of the pressure field on the streamlined surface of the dam model are obtained for the conditions of the passage of storm short and long waves. The features of the wave motion transformation near the dam and the characteristic regions of the frequency spectrum of the wave pressure on its surface are shown. Studies have been carried out to determine the sustainable structure of the dam and a step-like dam with two berms that can withstand storm loads is proposed.

Study of Geometric Elements for the Proposed Protecting Dam Reservoir in Al-Fat'ha Area, Iraq

Partially constructed Makhul dam may collapse after the operation due to the geological and geotechnical background of the foundations zone, and the presence of gypsum layers in this zone, Then the construction of Al-Fat'ha protection dam is one of the proposed solutions. The present study used the geometric analysis method to investigate the ability of Al-Fat'ha planned protecting dam to reduce the disasters of Makhul dam break. The new methodology used to derive the geometric elements of the two dams, and analyze the relations between these elements, and then exam the behavior of Al-Fat'ha proposed dam with and without the studied collapse scenarios. Fourteen collapse scenarios suggested for Makhul dam, from the level 140 m above sea level (a.s.l), to the maximum possible flood level 152 m (a.s.l). A mathematical model was derived to predict the level achieved as a response of cumulative storage in the protecting dam reservoir when the collapse of the Makhul dam occurred. The maximum level in the protecting dam reservoir to face the worst collapse scenario is 147 m (a.s.l), when the corresponding accumulated storage in the reservoir is 3414305769 m3. The results of the geometric analysis indicate that the optimum operating level for Al-Fat'ha dam in the operating conditions without Makhul dam collapse is 118.5 m (a.s.l), which corresponds to the capacity (39243587) m3. The total flooded area between the two dams was calculated for each collapse scenario of Makhul dam; it is about 44 km2for the worst scenario when nine villages on reservoir banks will submerge. Subsequently, the study confirmed the ability of Al-Fat'ha dam reservoir to contain the direct flood wave caused by the collapse of Makhul dam.