Water Engineering Department, Sari Agricultural Sciences and Natural Resources University, Sari, Iran.
Water Engineering Department, Sari Agricultural Sciences and Natural Resources University, Sari, Iran.
Sci Total Environ. 2022 Jul 20;831:154994. doi: 10.1016/j.scitotenv.2022.154994. Epub 2022 Apr 2.
Sustainable production in water-scarce regions entails not to overshoot the sustainable blue water availability (BWA), which in turn requires addressing environmental flow requirements (EFRs). We explored the long-term effects of agricultural development, before (1984-1997) and during (1998-2018) the operation of the modern irrigation and drainage network of Tajan (TIDN), northern Iran, on the sustainability of blue water consumptions. A combination of different methods were applied to estimate hydrological EFRs of rivers, ab-bandans (traditional water reservoirs), and groundwater resources. Three major pollutants in the region's water resources, including nitrogen, phosphorus, and salinity, were used to estimate water quality EFR. Monthly agriculture water footprints (WFs) were calculated using the AquaCrop model, and then were compared with the region's BWA, which was calculated by subtracting monthly EFRs from monthly natural runoff. When WF exceeded BWA, the production system includes unsustainable water consumption. The EFR satisfaction of surface water decreased after TIDN operation by about 19%. Unmanaged nitrogen application and post-TIDN overexploitation of groundwater resulted in substantial increase in groundwater EFR violation. The TIDN led to more water consuming cropping pattern resulting in increased agricultural water consumption by about 73%. Overall, agricultural development in TIDN was beyond the capacity of the area, which resulted in up to about 167 MCM y unsustainable blue water consumption. Based on the results, the new framework presented for assessing agro-environmental sustainability could assist managers and policy makers to modify agricultural systems according to environment resilience.
在水资源匮乏地区实现可持续生产，需要避免过度消耗可持续蓝色水（BWA），而这又需要满足环境水流需求（EFR）。本研究在伊朗北部塔简（Tajan）现代化灌溉排水网络运营之前（1984-1997 年）和期间（1998-2018 年），探讨了农业发展对蓝水消耗可持续性的长期影响。采用了多种方法的组合来估算河流、ab-bandans（传统水库）和地下水资源的水文 EFR。该地区水资源中的三种主要污染物，包括氮、磷和盐度，被用于估算水质 EFR。利用 AquaCrop 模型计算每月农业水足迹（WF），然后将其与该地区的 BWA 进行比较，BWA 是通过从每月自然径流量中减去每月 EFR 得出的。当 WF 超过 BWA 时，生产系统就包含了不可持续的水消耗。TIDN 运营后，地表水 EFR 满意度下降了约 19%。未经管理的氮施用量和 TIDN 后地下水过度开采导致地下水 EFR 违规大幅增加。TIDN 导致了更耗水的种植模式，使农业用水量增加了约 73%。总的来说，TIDN 的农业发展超出了该地区的承受能力，导致多达约 1.67 亿立方米的不可持续蓝色水消耗。基于研究结果，为评估农业环境可持续性而提出的新框架，可以帮助管理者和政策制定者根据环境弹性来修改农业系统。
