University of Twente Student Theses


Assessing the Groundwater Dynamics in a Semi-Arid Region (Konya Closed Basin, Turkey)

Obioma Nze, Kemdinachi Emmanuel (2010) Assessing the Groundwater Dynamics in a Semi-Arid Region (Konya Closed Basin, Turkey).

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Abstract:Konya closed basin in the centre of Turkey has in the past 3 decades witnessed a decline in groundwater level. To gain insight on the water availability in order to better manage the water resources, water balance of the Tuz Lake was calculated. The Tuz Lake, in the north of the basin is a tectonic salt lake and the terminal point for groundwater flowing from the Taurus Mountains in the south, quantifying its hydrologic components like precipitation, evaporation and runoff served as parameters to estimate the net groundwater flow. The input parameters for the spreadsheet based water balance calculation were monthly precipitation, evaporation and runoff. Mean annual estimates calculated for precipitation, evaporation and runoff is 22MCM, 32MCM and 5 MCM respectively, from which annual net groundwater flow was calculated to be 5MCM. Precipitation and evaporation play important roles in the lake hydrologic dynamics, this is observed as the lake surface area shows a trend with precipitation and decreases with increased evaporation. Evaporation is the main control on the lake salinity as the basin is hydrologically closed (Leng, Roberts et al. 1999). The assumption that the groundwater head has been declining over the years which have resulted in drying out of lakes, ephemeral streams and wetlands were observed in the study. Time series graphs from well level data (1978 – 2009), and a spatio-temporal mapping of groundwater head from 4 wells close to the Tuz Lake were used to assess the rate of head decline, and estimates of 0.7m/year and 0.5 m/year were obtained respectively. The groundwater head decline also reflected on the water balance calculation having an annual net ground water flow of 18MCM, 13 MCM, 7MCM and 4MCM for 2000, 2003, 2006 and 2009 respectively. The major cause of this declining groundwater level is increased abstraction for irrigated agriculture and industrial use, this may lead to groundwater levels falling bellow the lake bottom, ceasing the recharge to the Tuz Lake. In view of the findings of this study, the water resources of the Konya closed basin needs to be better managed, especially the groundwater which is the only dependable water resource in the basin, to enhance availability for the environment and human use.
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
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