Effect of Land Use Trends on the Amount of Agricultural Water Consumption in Urmia Lake Watershed in the Next 20 Years Using Markov Chain

Subject Areas : Water resources management

Kiyoumars Roushangar ¹ , Mohammad Taghi Aalami ² , Hassan Golmohammadi ³

1 - Professor, Department of Water Civil Engineering, Faculty of Civil Engineering, Tabriz University, Tabriz.
2 - Professor, Department of Water Civil Engineering, Faculty of Civil Engineering, Tabriz University, Tabriz.
3 - PhD Student in Water Engineering and Hydrological Structures, University of Tabriz, Tabriz.

Received: 2022-07-31 Accepted : 2022-10-17 Published : 2022-12-22

Keywords: Markov chain, Automatic cells, Urmia Lake Basin, Water consumption, Land use changes,

Abstract :

Background and Aim: Reducing the water level of Urmia Lake and its effects on the environment around the lake has been one of the important national and international issues and challenges in the last two decades. In accord with the studies, one of the critical factors affecting this declining trend has been the rise in harvest, especially for agriculture. Accordingly, the purpose of this study is to simulate the future status of water resources in the Urmia Lake basin, influenced by the area of agricultural land uses.Method:  For this purpose, Landsat satellite image data for the period 2000 to 2020 are firstly classified using the SVM algorithm in ENVI5.3 software and the classification accuracy is analyzed using the Kappa Coefficient algorithm.In the following, the statistics and information related to the change of cultivation pattern (from arable to garden) and water sources discharging Lake Urmia are calculated. In the next step, the simulation of land use changes for 2030 and 2040 is done using two LCM and CA-MARKOV methods. And finally, after determining the amount of changes in each land use, the amount of water required for agricultural affairs in the catchment is simulated using NETWAT model.Conclusion: The results show that the area of two uses, irrigated agriculture and garden will increase from 1450 and 395 square kilometers in 2000 to more than 3600 and 1650 square kilometers in 2040, respectively, This will increase the amount of water Needed or agriculture from 1,500 million cubic meters in 2000 to more than 4,100 million cubic meters in 2040.Results: From 2000 to 2020, water consumption in irrigated agriculture has increased by 1253.05 Km2; which according to Markov's prediction method, this amount will reach 2049.54 Km2 in 2040 that raises the amount of water consumption by 1 billion and 473 million cubic meters. The gardens land use has increased by 688.02 Km2 from 2000 to 2020, and according to Markov's prediction method, this amount will reach 1276.14 Km2 in 2040, which raises the amount of water consumption by 703 million cubic meters. From 2000 to 2020, 367.06 Km2 has been added to the drayland farming, which according to the prediction of Markov method, this amount will reach 531 Km2 in 2040, which soars the amount of water consumption by 253 MCM.