Previous studies have shown that screens may be utilized efficiently for dissipating the energy of water. For the present study, a series of experimental works are executed to investigate the tailwater and multiple screen effects on the energy dissipation through screens. Water flowing beneath a sliding gate is used to simulate the flow downstream of a hydraulic structure. In the present study, one double screen and two double screen arrangements with porosity of 40% and inclination angle of 90 degree is used. A tailwater gate structure is used to adjust the tailwater depth. The major parameters for the present study are upstream flow depth, tailwater gate height, location of the screen together with the supercritical upstream flow Froude number for a range covering from 5.0 to 22.5. The gate opening simulating a hydraulic structure is adjusted at heights of 2 cm and 3 cm during the study. The results of the experiments show that the tailwater depth has no significant additional contribution on the energy dissipation, whereas multiple screen arrangement dissipates more energy as compared to one double screen arrangement.

In this study, the first hardfill dam in Turkey, Cindere Dam, is evaluated regarding current and alternative measurement systems in detail. Cindere Dam is a notable project, especially with its height as an example of hardfill dam, not only in Turkey but also in the world. First, the current instrumentation system of Cindere Dam is evaluated as a whole with reference to the parameters measured, instruments and data acquisition system. Second, an alternative instrumentation system is developed by using additional parameter and instruments to the current instrumentation system. Furthermore, each instrumentation system equipped with manual and automatic data acquisition systems is considered. The comparison between the current and the alternative instrumentation systems are also carried out in terms of technical and economical feasibility aspects. Although, the current instrumentation system is found to be satisfactory, it is observed that the alternative system promotes the current system in various aspects without increasing the cost significantly.

Within the confines of this study, seismic soil liquefaction triggering potential of a dam foundation is assessed within an integrated probabilistic seismic hazard assessment framework. More specifically, the scheme presented hereby directly integrates effective stress-based seismic soil liquefaction triggering assessment with seismic hazard analysis framework, supported by an illustrative case. The proposed methodology successively, i) processes the discrete stages of probabilistic seismic hazard workflow upon seismic source characterization, ii) numerically develops the target elastic acceleration response spectra for typical rock sites, covering all the earthquake scenarios that are re-grouped with respect to earthquake magnitude and distance, iii) matches the strong ground motion records selected from a database with the target response spectra for every defined scenario, and iv) performs 2-D equivalent linear seismic response analyses of a 56 m high earth fill dam founded on 24 m thick alluvial deposits. Results of seismic response analyses are presented in the form of annual probability of excess pore pressure ratios and seismically-induced lateral deformations exceeding various threshold values. For the purpose of assessing the safety of the dam slopes, phi-c reduction based slope stability analyses were also performed representing post-liquefaction conditions. After having integrated this phi-c reduction analyses results into the probabilistic hazard framework, annual probabilities of factor of safety of slopes exceeding various threshold values were estimated. As the concluding remark, probability of liquefaction triggering, induced deformations and factor of safeties are presented for a service life of 100 years. It is believed that the proposed probabilistic seismic performance assessment methodology which incorporates both phi-c reduction based failure probabilities and seismic soil liquefaction-induced deformation potentials, provides dam engineers a robust methodology to rationally quantify the level of confidence with their decisions regarding if costly mitigation of dam foundation soils against seismic soil liquefaction triggering hazard and induced risks is necessary.

Siltation in reservoirs is becoming an important problem as the dams are getting older in the world. The general dam practice has been implemented in a sequence that / planning, design, construction, operation of dam until the accumulated sediment prevents its purpose function or functions. Unfortunately, effects of sedimentation and fate of the left over dams in the future are not figured. Indeed, these negative effects could be avoided, life of the reservoir can be prolonged and even the reservoir will last forever by minimizing the sedimentation. Therefore in this study, the methods that provide extension of reservoir life are discussed hydraulically, economically and applicability point of view. In addition, there is open source package program RESCON which examines and compares some sediment removal techniques economically and also hydraulically. RESCON is used in conjunction with several cases / namely &Ccedil / ubuk Dam-I, Bor&ccedil / ka Dam and Muratli Dam. Moreover, some sensitivity analyses are carried out in order to scrutiny of the program for Turkish economic conditions.

Dams are important large structures providing vital benefits to human life. These strategic structures are necessary in order to supply water and energy and to control floods. Moreover, dams have important roles in regional development and national economy. Thus, the design of dams deserves rigorous studies. Deterministic approach may be acceptable for design of dams and may satisfy safety requirements if large safety factors are used. However, such an approach will not be cost-effective in economic terms. High safety factors utilized in deterministic approaches necessitates large dimensions. One remedy for this overestimation is integrating statistical information and techniques, such as Monte-Carlo simulations into the analysis and design of dams. Probabilistic approaches may result in more economical and reasonable designs. CADAM is a software program which allows the user to analyze dams using Monte-Carlo simulation technique. Uncertainties associated with tensile strength, peak cohesion, peak friction coefficient, normal upstream reservoir elevation, drain efficiency and horizontal peak ground acceleration are incorporated into stability and stress analysis using Monte-Carlo simulations. In this thesis, utilization of CADAM software is demonstrated on a case study. Cindere dam is evaluated in terms of structural safety

Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Anabilim Dalı, 2008. / Kaynakça var.

Tez (Yüksek Lisans) - Süleyman Demirel Üniversitesi, Fen Bilimleri Enstitüsü, İnşaat Mühendisliği Anabilim Dalı, 2009. / Kaynakça var.

Several dams throughout the United States have been built on karst terrains, where soluble limestone bedrock has been dissolved to form features such as caves, sinkholes, and underground rivers. In such karst regions, subsurface hydrology can play an integral role in the condition, operation, and safety of dams and should be considered during risk assessment. Patoka Dam, near Jasper, Indiana, is situated on a well-developed karst landscape/aquifer system, faces significant potential challenges, and recently underwent risk assessment. A groundwater flow investigation using multiple fluorescent tracer tests, analysis of water-table elevations, isopach mapping of the Glen Dean Limestone, and spring hydrograph analysis was performed to better understand local groundwater hydrology in the vicinity of the existing water-control structures. Dye-tracing results identified the local flow direction as south to north and the mean dye travel time from injection locations to Robert Hall Cave Spring (RHCS) as 8- 11 feet per hour. These results also indicate that groundwater is bypassing the control structures in the vicinity of the cut-off wall, but the geometry of these flow paths is not clear. The recharge area for RHCS, a significant groundwater discharge point downstream from Patoka Dam, was delineated and the existence of a groundwater divide in the area of the dike was confirmed. The location of this groundwater-basin boundary follows an estimation of where the Glen Dean Limestone outcrops along the perimeter of the dissected ridge that lies between Patoka Lake and RHCS. Spring hydrograph analysis shows that spring discharge is primarily influenced by local precipitation events. However, precipitation events can result in increased pool elevation making the relationship between spring discharge and pool elevation unclear within the data set. This groundwater investigation has provided a clearer characterization of the hydrogeology within the vicinity of Patoka Dam. In combining the various hydrogeologic results, some insight into the function and geometry of the local karst network that could potentially affect the integrity of the dam and/or dike structures has been provided.

Daugiau, kaip 80 % hidrografinio tinklo Lietuvoje sudaro melioracijos kanalai. Daugiau kaip 30 % bebrų populiacijos gyvena šiuose kanaluose. Bebrų veikla neretai trikdo normalų melioracijos sistemų funkcionavimą. Tyrimui pasirinktos dviejuose skirtinguose kraštovaizdžiuose esančios bebravietės (Molėtų bei Panevėžio rajonuose). Šiame darbe buvo tiriama bebraviečių tankumas, pasiskirstymas, erdvinės charakteristikos bei statybinės veiklos intensyvumas melioracijos kanaluose. Nustatytas bebrų poveikio mastas bei šio masto pokyčiai. Ištirtose teritorijose bebrų veikiama pusė melioracijos kanalų linijinio ilgio. Per 10 metų (1995-2005) bebraviečių skaičius melioracijos kanaluose praktiškai nepakito, taigi nekito ir melioracijos sistemoms daromas poveikis. / More than 80 % of hydro-graphical network in Lithuania is composed of drainage channels. More than 30 % of beaver populations in Lithuania live in drainage channels. Beaver activity often dislocates irrigations systems. This research was taken in two different landscapes. Beaver sites were visited in Moletai and Panevezys districts. Density, spread, dimensions and constructional activity were recorded in drainage channels. Also this study shows influence over the environment of changing number in beaver populations. Half of linear lengths of irrigation systems are influenced by beaver activity. The number of beaver sites did not change in a ten year period (1995-2005) as well as did not change the damage caused by beaver activity.

The intention of this work is to provide a deeper understanding of the engineering geological behaviour of granite saprolite and how this affects the engineering of such material, with specific reference to the construction of Injaka Dam in the north eastern portion of South Africa Whilst extensive investigation of weathered granites has been carried out internationally, very little detailed research on the nature of this material is documented locally. The construction of Injaka Dam afforded the opportunity to investigate the saprolite in detail. This study was initially submitted to the Department of Geology and Applied Geology at the University of Natal, Durban (renamed the University of KwaZulu-Natal in 2004) to fulfill the requirement of a Master of Science degree in 200 I. Following this submission, and supported by recommendations made by the external examiners and the project supervisor, it was agreed to upgrade the work and submit this thesis for the degree of Doctor of Philosophy. Intensive chemical weathering of granite at Injaka Dam site has resulted in the formation of thick saprolitic deposits overlying the weathered bedrock. The granite forms part of the 3 075 Ma Nelspruit Suite which has been intersected by the African erosion surface. The extensive, multicyclic period of weathering and erosion that formed this surface has resulted in deep (up to 35 m) chemical weathering of the underlying bedrock in this area. The construction of Injaka Dam on this material necessitated a thorough engineering geological investigation to understand the nature of the weathering and the possible influences it exerts on the engineering behaviour of the saprolite. This was accomplished by analysing the weathering of the granite and relating the effects of these weathering processes and changes to the engineering behaviour of the material. By applying various chemical and mineralogical indices to the weathered granite, the intensity of weathering and related changes could be quantified and compared with the engineering behaviour of the material. This was achieved by applying a series of engineering indices to the material and relating these to the quantified weathering changes. In this way tentative extrapolation of the engineering behaviour of the material could be gained and used to predict engineering performance. The resultant effects of the engineering behaviour of the material on the design and construction of the dam are also discussed. / Thesis (Ph.D.)-University of KwaZulu- Natal, 2004.