Assessing potential land suitable for surface irrigation using groundwater data and multi-criteria evaluation in Xinjiang inland river basin

Abstract

In the present study, suitability of land for irrigation based on groundwater in Xinjiang inland river basin with GIS-based Multi-Criteria Evaluation (MCE) techniques was evaluated with the aim to promote the development of regional agriculture. The critical elements that relatively large impact on the evaluation of irrigation suitability contain physical land characteristics (land use, soil and slope), climate (rainfall and evapotranspiration) as well as groundwater data (natural recharge modulus and aquifer productivity). These factors which adopted 1 km resolution were weighted by a pairwise comparison matrix and then reclassified and overlaid to identify the appropriate area suitable for groundwater irrigation. The current work also attempts to explore weight sensitivity initiated by both direct and indirect weight changes through applying the one-at-a-time (OAT) technique in a GIS platform. The weights in association with all criteria employed for suitability modeling were changed one-at-a-time (OAT) so as to study their relative influences on the ultimate evaluation results. The groundwater irrigation potential for farming was assessed using preliminary result of land suitable, suggesting that 519,292 km2 of land which is the sum of levels S1 and S2 could be used for irrigation directly and the rest needs to be diverted from other areas. A large portion of the irrigable land is located in the Ili river valley, south of the Altai Mountain, both sides of the Tianshan Mountains and north of Kunlun Mountains, which has access to shallow groundwater making it easier to extract. Through conducting field investigation, the groundwater alone might not be abundant to support all suitable land. Nevertheless, groundwater can be used for the supplementation of surface water resources for irrigation in the area.