河川径流还现计算是准确反映区域水资源状况的基础,同时也是水资源规划和决策的重要依据。选取甘肃省洮河流域李家村、红旗2个代表水文站长系列径流资料作为基础数据,在还原计算的础上,对洮河流域径流进行还现计算,同时对径流变化特征进行研究。结果表明：1956—2016年洮河流域李家村、红旗多年平均实测径流量分别为39.52×10⁸m³、44.66×10⁸m³,还原后多年平均天然径流量分别为39.69×10⁸m³、46.11×10⁸m³,多年平均还原水量分别为0.17×10⁸m³、1.45×10⁸m³,2站消耗水量主要用于农业灌溉;2站天然径流突变趋势基本一致,突变点均为1990年;李家村、红旗站径流多年平均天然径流量修正还现后分别为31.76×10⁸m³、38.77×10⁸m³,减少径流量分别为7.93×10⁸m³、7.04×10⁸m³,分别减少20%、15%;还现后李家村站年径流呈现略微增加趋势,而红旗站年径流量呈现略微减小趋势;径流量呈现20世纪50年代和70年代—21世纪00年代低于多年平均值,21世纪10年代高于平均值和不同丰、平、枯状态的年代际特证。研究结果为流域水资源调查评价提供基础支撑,对促进流域水资源高效利用和优化配置,指导区域水资源综合管理与社会经济发展具有重要作用。

The calculation of current river runoff is not only the basis of accurately reflecting regional water resources but is also the important basis of water resource planning and decision-making. Runoff reduction was divided into “forward reduction” and “backward reduction”. “Forward reduction” referred to the reduction calculation of the measured annual runoff series into the natural annual runoff series before a large number of water conservancy projects were built in the basin. “Backward reduction” referred to the conversion of the natural annual runoff series of each representative station in the region to the annual runoff series under the current conditions, i.e., the current calculation. The “forward reduction” evaluation results reflect the natural state of the water resources in the basin. With the rapid development of human economy and society, a large number of water conservancy projects have been built, and the regional underlying surface conditions have been much changed, so they cannot be returned to the natural state. Therefore, the results cannot be used directly in the planning, design, and decision-making of water conservancy projects. The current runoff calculation can truly reflect the construction and utilization of water conservancy projects and provide technical support for scientific and rational allocation and sustainable development of regional water resources. The Taohe River is the largest tributary in the upper reaches of the Yellow River. However, with the change in climate and human activities on the underlying surface, the runoff of the Taohe River has decreased significantly in the past two decades. The Lijiacun and Hongqi hydrological stations in the Taohe River Basin were selected for the basic data, the current runoff in the Taohe River Basin was calculated using the results of the reduction calculation, and the characteristics of runoff change were studied. The results showed that from 1956 to 2016, the average annual measured runoffs of the Lijiacun and Hongqi stations in the Taohe River Basin were 39.52×10 ⁸ m³ and 44.66×10⁸ m³, respectively. After the reduction calculation, the average annual natural runoffs were 39.69×10⁸ m³ and 46.11×10⁸ m³, respectively. The average annual reduction water volumes were 0.17×10⁸ m³ and 1.45×10⁸ m³, respectively. These two water consumption stations are mainly used for agriculture. The anomaly change trends of the average natural runoff in the two stations were the same, and the anomaly change point was 1990. The corrected current runoff amounts at the Lijiacun and Hongqi stations were 31.76×10⁸ m³ and 38.77×10⁸ m³, respectively, and the revised amounts were 7.93×10⁸ m³ and 7.04×10⁸ m³, respectively. The runoffs of the Lijiacun and Hongqi stations decreased by 20% and 15%, respectively. At present, the annual runoff of the Lijiacun station shows a slight increasing trend, whereas the annual runoff of the Hongqi station shows a slight decreasing trend. The interannual changes of runoff in the 1950s and 1970s—1990s were lower than the multiyear average runoff, of which that of the 2110s was higher than the multiyear average runoff. The research results provide basic support for the investigation and evaluation of water resources in the basin and have important practical reference significance for promoting regional integrated water resource management and scientific deployment, guiding regional integrated water resources planning and socio-economic development.