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Bibliographic Details
Main Author:	Mohammmed, FAHMY
Format:	Recurso digital
Language:
Published:	Zenodo 2023
Online Access:	https://doi.org/10.5281/zenodo.15182541
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Table of Contents:

Over the past few decades, climate change and population growth in semi-arid regions, especially in the Middle East, have caused water shortages. To mitigate this problem, an increasing number of dams have been constructed. The Kurdistan Regional Government (KRG) decided to build forty dams to control water shortages and drought problems and decrease the of effect climate change. The site selection for all these dams requires geological engineering, hydrology, metrology, and satellite image studies. The selected river basin in this study (Kanarwe) is considered the priority location for dam construction by the KRG in the future. The Kanarwe River Sub-Basin (KRB) is part of an enormous transboundary watershed called the Lesser Zab River Basin (LZRB) with 750 mm annual average rainfall. It covers about 1542 km2, of which 83% is located within the Iraqi border and 17% is located within the international border of Iran. This dissertation concludes the best site for dam construction on the Kanarwe River based on three aspects: hydrological conditions, geophysical, and engineering geology studies within the lesser Zab Basin. The first aspect is a hydrological perspective aimed at estimating the catchment area, the volume of water, the peak flood, and the peak time based on different unit hydrographs (UH). The HEC-1, HEC-HMS, Snyder model, TR55, Soil Conservation Service (SCS-CN), and Rational Unit Hydrographs are selected to calculate the peak flood and peak time in the KRB basin. The results of the peak discharge and the peak time of the HEC-1 and HEC-HMS models gave similar results: Qp=739.93m3/sec, Tp=20hrs; Qp=800 m3/sec, Tp=12hrs, respectively. The results from TR55 are Qp=181.1m3/sec; Tp=14hrs, while the Rational and Snyder's models are somewhat close to each other; they are Qp = 341.13 m3/sec, Tp=11.65hrs; Qp=443m3/sec, Tp=19.9hrs, respectively. Comparing these model results with observed data 263 m3/sec (Gumbel Approach) reveals that Snyder, rational and TR55 are more accurate because these three models work more with geographic location, climatic data, and geomorphic parameters. The second aspect is an electrical resistivity 2D tomography survey to detect cavities or faults. Different traverses were taken at the dam site (left side, right side, and foundation), and the data were processed with ProsysII and Res2Dinv. The results show three zones of resistivity, with the first low resistivity zone ranging from 15 to 45 Ohm. m that they are siltstone and marl of the Tanjero Formation. The second zone is a moderate resistivity zone ranging from 45 to 90 Ohm. m, that they are Sandstone and Siltstone of the Tanjero Formation. The third resistivity iv zone, ranging from 90 to 450 Ohm. m is the limestone of the Aqra Formation. The result of the profile inversion shows that there is no cavity or fault detection at the dam site. The third aspect is applying an accurate rock mass evaluation for the proposed dam site, composed of an interlayer of limestone rocks (Aqra Formation) and flysch rocks (Tanjero Formation). Three rock mass classification systems are used to evaluate rock masses at the site: geological strength (GSI), dam mass rating (DMR), and rock mass rating (RMR) geomechanical classification systems. The results of the GSI value for rock masses in twenty units at the dam site reveal that the values of the carbonate rocks of the Aqra Formation are between 74 and 77, while the flysch rocks of the Tanjero Formation give a lower value of 45 to 55. The strength properties of all rock mass units were determined by the Hoek-Brown failure criterion using the RocLab program. The DMRSTA, which indicates the stability of the rock foundation of the Aqra Formation, ranges from 70.4 to 83.4, and for flysch of the Tanjero Formation ranges from 43.7 to 60. These values indicate no stability problems except for some flysch rock masses. The foundation excavation desirability and consolidation grouting evaluation was done based on RMRDB. It indicates that limestone units are suitable for gravity, rock-fill, earth-fill, and Arch dams; meanwhile, the clastic rocks required systematic grouting for Arch dams and spotted grouting for gravity dams. The rock mass units were evaluated based on the ratio of the dam's deformation modulus and the deformation modulus of foundation rock mass (Ec/Em) to determine site suitability for dam types. This ratio for different limestone rock mass units ranges from 0.3 to 0.93, indicating that the site is suitable for different kinds of dams such as gravity, fill, and arch. While the (Ec/Em) for clastic rock ranges from 1 to 6.4, indicating that some units have a serious problem that needs treatment. The DMRDEF (RMR related to relative Deformability) values are 69.3–80.2 for limestone units. However, the DMRDEF value for clastic rock mass units ranges from 40-50, and these values generally show no deformability problems. A new procedure and classification were suggested for quantifying stress relaxation and damage level (disturbance factor D) in rock masses as a novelty for this dissertation work, where calculating the rock mass disturbance factor is based on the joint spacing and strength index (Is50) of the intact rock, and the new disturbance factor is used in Hoek et al. (2002) equation and RocLab software feature to evaluate the foundation rock masses. Based on the hydrological, engineering geological, and geophysical assessments for the Kanarwe River Basin and the proposed dam site, the site is very convenient for the construction of different types of dams with a height of 80 m from the valley floor of 817 m, and the water v level in the reservoir will reach an elevation of 897 m above mean sea level and the dam storage volume reach to 440 MCM. Finally, due to the near location of the proposed dam from Sulaymaniyah City, it will provide fresh drinking water and create a good space for tourism in the future.

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