The southeastern United States observed a widespread expansion in area under irrigation over the past half century, primarily due to inadequate rainfall during crop growing season. In this region, El Niño Southern Oscillation (ENSO), a seasonal-to-interannual climate-variability phenomena, may result in bringing suitable precipitation in any year while generating extremes of too much or too little precipitation in others. Therefore, this climate variability phenomena results in uncertainties over the availability of stream water for withdrawals to meet irrigation needs. The overall goal of this study was to quantify the impact of ENSO on the amount of water that can be sustainably withdrawn from streams for irrigation. The specific objectives of this study were to (1) quantify the relationship between ENSO and precipitation, and ENSO and simulated streamflow; (2) develop surface water withdrawal prescription for irrigation without disturbing the ecological integrity of streamflow; (3) quantify the area of watershed that can be irrigated via surface water withdrawals from different order streams; and (4) determine pond size for the storage of withdrawn water from streams for irrigation. The study was conducted in the Swan Creek watershed located in Limestone County of north Alabama, United States. The Soil and Water Assessment Tool (SWAT) model was used to simulate streamflows and develop water withdrawal prescriptions. The La Niña phase of ENSO generated more rainfall from January to March, and the El Niño phase generated more rainfall from May to December (except October). The results of this study indicate that as a function of year, during a La Niña phase 14% to 55% more water can be sustainably withdrawn from streams in the winter months (January to March) than the El Niño phase. Furthermore, irrespective of the ENSO phase, about 42% more water could be withdrawn during the noncrop growing months than the crop growing months. Based on the water withdrawal criteria, about 16% of the watershed cropland area can be irrigated if the withdrawals are made throughout the year, 9% if stream water is withdrawn in noncrop growing season months, and 5% if stream water is withdrawn in the crop growing season. If farmers plan water withdrawal in accordance with the ENSO phase, it would not only provide them ample volume of water for irrigation during the crop growing season but would also help to maintain stream water quality and aquatic biota.

中文翻译：

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基于厄尔尼诺南方涛动预测的灌溉雨水收集创新方法

在过去的半个世纪里，美国东南部的灌溉面积普遍扩大，这主要是由于作物生长季节降雨量不足。在该地区，厄尔尼诺南方涛动 (ENSO) 是一种季节性到年际的气候变化现象，可能会导致任何年份的降水量适宜，而其他年份的极端降水量过多或过少。因此，这种气候变化现象导致了用于取水以满足灌溉需求的溪水可用性的不确定性。本研究的总体目标是量化 ENSO 对可从溪流中可持续抽取用于灌溉的水量的影响。本研究的具体目标是 (1) 量化 ENSO 与降水之间的关系，ENSO 和模拟水流；（2）在不干扰河道生态完整性的前提下，制定灌溉取水配方；(3) 量化可通过不同等级河流抽取地表水灌溉的流域面积；(4) 确定用于储存从溪流中抽取的灌溉水的池塘大小。该研究在位于美国阿拉巴马州北部石灰石县的 Swan Creek 流域进行。土壤和水评估工具 (SWAT) 模型用于模拟河流和制定取水处方。ENSO 的拉尼娜阶段在 1 月至 3 月产生更多降雨，厄尔尼诺阶段在 5 月至 12 月（10 月除外）产生更多降雨。这项研究的结果表明，作为年份的函数，在拉尼娜阶段，冬季（1 月至 3 月）从溪流中可持续抽取的水量比厄尔尼诺阶段多 14% 至 55%。此外，无论 ENSO 阶段如何，在非作物生长月份可以比作物生长月份多抽取约 42% 的水。根据取水标准，全年取水可灌溉流域农田面积约16%，非作物生长季取水可灌溉9%，非作物生长季取水可灌溉5%。作物生长季节。如果农民按照 ENSO 阶段计划取水，不仅可以在作物生长季节为他们提供充足的灌溉用水，还有助于保持溪流水质和水生生物群。