Assessing the groundwater dynamics and impacts of water saving in the Hetao Irrigation District, Yellow River basin
Assessing the groundwater dynamics and impacts of water saving in the Hetao Irrigation District, Yellow River basin
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DOI：
10.1016/j.agwat.2010.08.025
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发表时间：
2010-12
期刊：
影响因子：
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通讯作者：
Xu Xu-Xu;Guanhua Huang;Z. Qu;L. S. Pereira
中科院分区：
文献类型：
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作者：
Xu Xu-Xu;Guanhua Huang;Z. Qu;L. S. Pereira
由于水资源严重短缺和非农业部门需求增加，黄河流域分配给农业部门的水资源正在减少。在大型灌区，采用节水措施，改善渠系，采用节水灌溉技术，调整种植模式，是农业可持续发展和流域环境平衡的需要。采用节水做法可以降低地下水位，控制与过度灌溉有关的盐碱化影响。然而，评估节水做法对地下水系统的影响需要进一步调查。以河套灌区解放闸灌区为例，分析了地下水位的时空动态。为此，开发了一个集总参数地下水平衡模型，以评估各种节水措施的影响。该模型进行了校准，每月的数据集相对于非冻结期的1997-1999年和验证数据集从2000年到2002年。结果表明，渠道渗漏和深层渗漏分别占地下水年补给量的48%和44%。通过直接蒸发和植物根系吸收的地下水排放量占全年地下水排放总量的82%。经验证后，该模型被应用于评估各种渠道和农田灌溉节水措施的影响。据观察，运河系统的改进（例如，渠道衬砌、升级水利调控结构、改进输水时间表）可能会使地下水位下降0.28- 0.48米，这取决于这些措施的执行程度。当节水技术应用于运河和农场系统时，预计地下水位下降幅度会更大。地下水位的下降有利于控制盐度，减少毛细上升，从而减少地下水蒸发和植物根系的吸收;减少量可能达到128毫米。然而，预测可能会发生变化，这取决于如何应用节水措施，这可能是不同的假设，因此，有必要进行后续的干预措施，以更新预测。结果表明，需要进行适当的研究，以改善灌溉管理时，地下水位的下降将减少地下水对植被生长的贡献。
Water resources allocated to the agricultural sector in the Yellow River basin are being reduced due to severe water scarcity and increased demand by the non-agricultural sectors. In large-scale irrigation districts, the application of water-saving practices, e.g., improving the canal system, using water-saving irrigation technology and adjusting cropping patterns, is required for the sustainable agricultural development and the river basin environmental equilibrium. Adopting water-saving practices leads to lowering the groundwater table and to controlling salinity impacts related to excessive irrigation. However, assessing the effects of water-saving practices on the groundwater system requires further investigation. The Jiefangzha Irrigation Scheme of the Hetao Irrigation District is used as a case study for analyzing the temporal and spatial dynamics of the groundwater table. A lumped parameter groundwater balance model has been developed with this purpose and to assess impacts of various water-saving practices. The model was calibrated with monthly datasets relative to the non-frozen periods of 1997–1999 and validated with datasets from 2000 to 2002. Results indicate that canal seepage and deep percolation account for respectively 48% and 44% of the annual groundwater recharge. Groundwater discharge by direct evaporation and plant roots uptake represents 82% of the total annual groundwater discharge. After validation, the model was applied to assess the impacts of various canal and farm irrigation water-saving practices. It was observed that improvements in the canal system (e.g., canal lining, upgrading the hydraulic regulation and control structures, improving delivery schedules) might lower the groundwater table by 0.28–0.48m, depending upon the level of implementation of these measures. Higher declines of the groundwater table are predicted when water-saving technologies are applied at both the canal and the farm systems. That decline of the water table favours salinity control and reduces capillary rise, thus reducing the groundwater evaporation and uptake by plant roots; that reduction may attain 128mm. However, predictions may change depending on the way how water-saving measures are applied, which may be different of assumptions made; therefore, there is the need to perform a follow-up of the interventions in order to update predictions. Results indicate the need for appropriate research leading to improved irrigation management when the decline of the groundwater level will reduce groundwater contribution to vegetation growth.