DOHUK SYNCLINE AS AN ARTIFICIAL RECHARGE AQUIFER, NORTHERN IRAQ
Artificial recharging was carried on Dohuk Syncline. The syncline is located between Baikher Anticline to the north and Dohuk Anticline to the south. Dohuk city occupies the surface area of this structure. The syncline extended about 17.1 Km in a generally east-west direction. It is a narrow syncline due to its location between two steep limbs of Baikher and Dohuk anticlines. Moreover, the syncline is very narrow near Itut village which represents the eastern plunge of the syncline and becomes wider towards the west near Aloka village. Alluvial deposits, vegetation and urbanization cover the surface of this syncline where the Fatha and ridges of Pila Spi formations surround it.
The distinct property of the Pila Spi Formation of being well-jointed limestone makes it an excellent and adopted aquifer for water storage. Moreover, it underlys Fatha Formation and overlys Gercus Formation, which are considered as aquitard and aquiclude confining beds respectively.
The geometry and the shape of this syncline were determined by mathematical (Lagrangian Interpolation) method. It was used to obtain the subsurface or the hidden parts of the syncline depending on the bore-holes data and the available seismic sections. This method was applied on three transverse sections. Finally, SURFER program was utilized to display the final geometrical shape of Dohuk Syncline in three dimensions.
The project is an attempt to determine the capability of this syncline for artificial recharge of water and to be used as an aquifer for the city domestic uses. The size of this aquifer is estimated as 7.38 Km3 and the pore size is 1476452509.2 m3 depending on the limestone porosity of 20%. In addition, the infiltration of rainfall is determined as 2521116 m3/year. Consequently, the aquifer needs very long time to be fully recharged. Subsequently, natural recharging is not enough and necessitates a proposal for recharging the aquifer artificially. Moreover, some ideas were proposed to achieve this purpose.