Evaluation of Different Water Management Practices for the Sustainable Use of Groundwater Resources in the Konya Closed Basin

agricultural regions of the country and critical to its food supply and security. KCB is characterized

by a semi-arid climate, with mean annual precipitation of 379 mm. Since most of the rain occurs in

the winter months outside the agricultural season, groundwater is used extensively for irrigation.

In recent years, groundwater levels have experienced sharp declines due to the expansion of

irrigated lands and the switch to more water-demanding crops. This problem is exacerbated by a

large number of unregulated groundwater extraction wells. A regional numerical surfacesubsurface

water flow model based on the UZF1-MODFLOW computer program was developed

for the science-based management of this vital resource. The model simulates transient vertical

flow through the vadose zone and groundwater flow through the underlying aquifer system.

Because of the lack of direct measurements of groundwater abstraction rates, the time-dependent

monthly rate of groundwater abstraction was estimated indirectly based on crop water

requirements and historical land allocation for the different crops. The hydrogeology of the site

was characterized from borehole data and conducted pumping tests. Historical groundwater level

observations between the years 2000-2020 were used to calibrate the model. The key calibration

parameter was irrigation efficiency. The challenges of developing and calibrating a regional water

flow model are discussed. The calibrated model was then used to simulate the impact of different

groundwater conservation scenarios: a slow and a fast transition to less water-demanding crops

and the adoption of an optimized cropping pattern. The scenarios are evaluated against the

business-as-usual scenario that assumes historical water demand trends remain unchanged. The

results underline the urgent need to consider a holistic approach to address the water deficit of

the basin. Overall, the model can help policy and decision-makers explore more efficient and

sustainable groundwater management practices.

This work was developed under the scope of the InTheMED project. InTheMED is part of the PRIMA

program supported by the European Union’s HORIZON 2020 research and innovation program

under grant agreement No 1923.