Geophysical and Geological investigation of the Delga proposed Dam Site, Qala Diza, Sulaimani City, Kurdistan Region, NE-Iraq


Bakhtiar Q. Aziz, Salahalddin S. Ali, and Kamal H. Karim

Faculty of Science and Science Education  , University of Sulaimani



Abstract:
The use of two geophysical methods and geological study in the investigation of the
geological setting is aimed at evaluating the feasibility of the area for establishing a dam
foundation and reservoir. 2D resistivity tomography was conducted on abutments while
GPR was used on the river terraces in the trough of the valley. The framework and
mutual relations of the geophysics, stratigraphy, lithology, structure, hydrologeology and
geotechnique are used to study feasibility of a segment of river valley for dam building.
The study is aided by detail and uptodate geological maps and geological cross sections
which are all base on field data and geophysical measurements. This proposed dam is
located at the southeast Delga village and about 20.0 km upstream of Dokan reservoir on
little Zab River and about 19.5 km from the Iraqi-Iranian border. The dam site and
surround areas are located in the Imbricated Zone which characterized by southwest
overturning of the folds. The dam site is located on one of the overturned syncline in which
Shiranish and Kometan Formations are exposed and the foundation and abutments of the
dam are located on latter formation. The trend of the dam axis is N80W and the dip of the
strata of the Kometan Formation is nearly parallel to the dam axis. This structure relation
with dam axis improves water tightness and stability of the dam abutments against sliding
and collapse. The 2D resistivity tomography and GPR survey showed that there are
underground week zones (cavern and fractured zones) in restricted limited area. The site
is water tight as the river descended inside fresh Kometan and Shiranish Formation.

References
1-Ajayi O, Olorunfemi MO, Ojo JS, Adegoke-Anthony CW, Chikwendu KK, Oladapo MI, Idornigie AI, Akinluyi F (2005). Integrated geophysical and geotechnical investigation of a dam site on River Mayo Ini, Adamawa State, Northern Nigeria. Afr. Geosci. Rev., 12(3): 179-188.
2-Bellen, R. C. Van, Dunnington, H. V., Wetzel, R. and Morton, D. Lexique Stratigraphique International. Asie, Iraq,.(1959), 3c. 10a, 333 p.
3-Biswas AK, Charttergee S (1971). Dam Disasters - An Assessment. Eng. J. (Canada), 54(3): 3-8.
4-Buday, T. (1980). Regional Geology of Iraq: Vol. 1, Stratigraphy: I.I.M Kassab and S.Z. Jassim (Eds) D. G. Geol. Surv. Min. Invest. Publ. 445p.
5-Buday, T., and Jassim, S. Z., (1987). “The Regional geology of Iraq, Tectonism Magmatism, and Metamorphism”. I.I. Kassab and M.J. Abbas (Eds), Baghdad
6-Jassim, S.Z. and Goff, J.C. (2006). Geology of Iraq. Dolin, Prague Museun, Berno. 341pp.
7-Karim, K.H. and A.m. Surdashy, (2005). Paleocurrent analysis of Upper Cretaceous foreland basin: a case study for Tanjero Formation in Sulaimaniya area, NE-Iraq, Iraqi Journal of Science, Vol. 5, No.1 pp.30-44.
8-Karim, K.H. (2004). Basin analysis of Tanjero Formation in Sulaimaniya area, NE-Iraq. Unpublished Ph.D. thesis, University of Sulaimaniya, 135p.
9-Karim, K. H., Koyi, H. Baziany, M. M. and Hessami K. (2011). Significance of angular unconformities between Cretaceous and Tertiary y strata in the north western segment of the Zagros fold–thrust Belt, Kurdistan Region, NE Iraq. Geological Magazine, Vol.148, issue, 5l6. P.925-937.
10-Loke, M.H., and Dahlin T. (2002): A combine Gauss-Newton and Quasi-Newton inversion methods for interpretation of apparent resistivity pseudosections, Paper presented at the 3rd Meeting of the Environmental and Engineering geophysics Society-European Section, Sept. 1997, Aarhus, Denmark.
11-Olorunfemi MO, Ojo JS, Sonuga F, Ajayi O, Oladapo MI (2000a) Geoelectrical and Electromagnetic Investigation of the Failed Koza and Nasarawa Earth Dams Around Katsina, Northern Nigeria. J. Mining Geol., 36(1): 51 - 65.
12-Olorunfemi MO, Ojo JS, Sonuga F, Ajayi O, Oladapo MI (2000b). Geophysical Investigation of Karkarku dam embankment. Global J. Pure Appl. Sci., 6(1): 117-124