Using Pumping Tests and Two Techniques of the Water Balance to Assess the Aquifer Hydraulic Characteristics and the Groundwater Recharge of Shewasoor Sub-Basin Kirkuk, NE Iraq
Shewasoor sub-Basin represents one of the hydrogeological sub-basins of the Lower Zab River and covers an area of 160 km². It is located between longitude 44º 31' 23.9" – 44º 37' 75" and latitudes 35º 45' 28.9"–35º 48' 59". The basin is bounded from the north and northeast by the Taqtaq anticline and Chamchamal anticline represents the western and southwest boundaries, while the southeast boundary is a surface water divide with the Al- Khassah River sub-basin. The groundwater distribution levels and movement maps show that the water depths range between 414-862 m a.s.l, and it moves in line with the movement of water surface drainage, as it moves from the east, southeast, south and southwest (recharge areas) towards the northwest regions, while the water depths vary from the ground level between relatively deep in the southwestern part to medium and shallow in the rest of the parts. An evaluation of the hydraulic characteristic and groundwater recharge by two techniques of the water balance for aquifers of the study area has been carried out. The results showed that the hydraulic properties, transmissivity value ranges between 5.6 - 169 m²/day, the hydraulic conductivity values range between 0.67 - 5.1 m/day, and the storage coefficient values, ranging from the lowest value (0.0013) to the highest value (0.27). The results reflected that the types of the aquifers are unconfined and semi-confined as well as heterogeneous and anisotropic. after analyzing and calculating the climatological parameters of Koya meteorological station as the nearest station to the Shewassor area, showed the water surplus is equal to 333.94 mm which represent 53.8% of the annual rainfall value (628.3mm) and the surface water is equal to 138.5mm as a runoff. 199.44mm (31.74%) out of the annual rainfall is percolated to recharge the aquifers of Shewasoor, while water table fluctuation method WTF showed there are two zones of specific yield in the study area and the groundwater recharge is 232.06mm, so can be said that the 215.8mm is the average of the groundwater recharge in Shewasoor sub-basin. Finally, and by using the groundwater flow net analyzing technique that the amount of groundwater discharged from the study area is about 12 million m3 (MCM) and the renewal groundwater storage is 19.42 million m3 (MCM), which means there is 7.39 million m3 is groundwater can be invested as a safe investment.