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Conjunctive use of surface and groundwater is an effective approach to relief water resources shortages and its uneven temporal and spatial distribution in arid inland regions of central Asia. In this paper, 16 characteristic factors of water resources and related systems which are sensitive to different types of conjunctive use were selected in order to develop an index system for evaluation impact of conjunctive use, based on the fundamental types of water resources conjunctive use in inland basins. In an attempt to address the issue of spring drought and summer floods in Tailan River Basin in Xinjiang, three scenarios of conjunctive use of surface water and groundwater, well-canal combination, piedmont reservoirs and groundwater reservoirs were investigated. The utilization of water resources and the response of its related systems were evaluated and analyzed quantitatively using the groundwater numerical simulation model (Visual MODFLOW). Furthermore, the impacts of conjunctive use were assessed using the method of multi-level fuzzy comprehensive assessment. The results show that the scheme of combination of Laolongkou piedmont reservoir regulation-groundwater development, is the best in terms of the evaluation of water conjunctive use effects, followed by the well-canal combination. The comprehensive effect of well-canal combination along with groundwater reservoir wouldn't be better than the former both. [ABSTRACT FROM AUTHOR]

Abstract: Groundwater is widely recognized as the most significant water resource for irrigation and drinking purposes in the extremely-arid inland river region. However, land use is a major force altering the hydrological processes over a range of temporal and spatial scales. Therefore, understanding the interaction between land use and groundwater processes will definitely contribute to formulate a regional sustainable development strategy and recognize the impact of land use on the groundwater flow regime in the Tailan River basin. A numerical simulation of groundwater level for the inland river basin and scenario analysis under land use using FEFLOW is presented. Spatial data of the regional land use were processed using GIS, and the effects of land use on groundwater level were simulated. The amount of irrigation water and pumped groundwater have the most remarkable influences on groundwater level as main source/sink factors. Their variations were simulated according to the irrigation systems with different crops. Other factors including percolation and evapotranspiration of precipitation and condensed water jointly exerted influences on groundwater level. Changes to farmlands had the greatest impact on Tailan River basin for groundwater level, and unused land and Gobi had the least impact on groundwater level. Groundwater level maintained a decreasing trend in the irrigated zone, and increasing groundwater pumping would further intensify the water shortage in Tailan river basin. This coupled effects resulted from land use and extensive groundwater pumping were considered as the major human-induced factors influencing the groundwater system in the extremely-arid inland river basins. The results can provide useful support for land use. Understanding hydrological processes at the watershed level is essential in land use and water resource planning and management, and the proposed approach can be used as a management and planning tool for evaluating the local and overall impacts of land use management on the surface and groundwater flow regimes. [Copyright &y& Elsevier]