The Groundwater Balance Assessment in Holy Karbala, Central Iraq

Abstract

Karbala is located in central Iraq, which is bounded by latitudes (32° 50' 15" - 32° 10' 15") and longitudes (43° 09' 41"– 44° 18' 56"), the area under study covers an area of 4,987 km2. It is a part of unstable shelf of the sedimentary plain zone and Al-Salman zone of the stable shelf, so it is a flat area, which gradually declines from the southwest towards the northeast. The geological formations which are exposed in the study area, having a range between middle Miocene and Pleistocene – Recent deposits. Two main aquifers were distinguished in the area, confined and unconfined one. Depending on the karbala meteorological station information (rainfall, temperature and humidity) from 1980 - 2019 utilizing Thornthwait formela's, the water overflow was accounted, appearing the renewed water store for the unconfined system, equalized to 111.0 *106 m3/year whereas the calculated constant volume of water for both systems was found to be equivalent to a total of 13.84 * 109 m3 However, after calculating the difference between the total water that in-coming the area (including, income subsurface runoff, recharge, fluctuation in monitoring wells and out-coming (including, discharge of pumping wells, outflow wells drainage, spring drainage, outcome subsurface runoff), the amount of change in the storage is found to be (+32.573 * 109 m3). The amount of positive change indicates the presence of excess water which can be added to both systems. The direction of the groundwater movements for the two main systems are highly matched between them as well as its similarity with the topographic surface.