Climatic Water Balance and Hydrogeological characteristics of Lailan Basin, Southeast Kirkuk - North of Iraq

Abstract

This paper examined the climatic water balance and hydrogeological conditions of the water bearing layers within Lailan basin. To achieve the water balance the meteorological data from Kirkuk station for the period (1970 to 2016) was used to calculate the water surplus and water deficit. Based on Mehta's model the water surplus (Ws) is equal to (127.86 mm/ year) representing 36.87 % of the total rainfall, while 63.13% of the total rainfall are water deficit. The study area is characterized by two main aquifer types, unconfined and semi-confined. Generally, groundwater recharge occurs from both sides of the basin toward the center and the general flow direction is from northeast to southwest. To determine the hydraulic properties of semi-confined aquifer, pumping and recovery tests data from seven wells in the study area were analyzed based on the Hantush-Jacob's (1955) and Theis recovery (1935) methods.The values of T, K ,Sc and S ranged from (79.63 – 753.8 m2/day ),(2.01 – 16.75 m/day ),(0.42 – 5.95 m2/day ) and (0.0068 - 6.134E-16 ) respectively . Due to the aquifer lithology heterogeneity the hydraulic properties varied from one location to another, reflecting the change of both porosity and permeability.