黄河上游不同用水情景下可调输沙水量概念探析与估算分析

近年来,黄河上游水沙关系不断恶化,造成沙漠宽谷河道淤积、萎缩现象日益突出,严重制约和影响了黄河上游防凌安全及水能资源综合开发与有效利用。黄河上游梯级水库的联合调度运行,是缓解河道泥沙淤积、发挥水库水沙调控效益、从而提高危险断面过流能力的有效技术措施之一。此文在初步探析黄河上游可调输沙水量基本概念的基础上,阐明了可调输沙水量与水库可调水量之间的相关关系,进而通过计算黄河上游龙羊峡水库1987~2010年可调水量,探讨了满足综合用水需求和发电用水需求两种情景模式下的黄河上游历年可调输沙水量及水库水沙调控效益。结果表明:满足黄河上游综合用水需求情景下,龙羊峡水库富余水量可完全满足下游河道输沙用水需求;满足发电用水需求情景下,发电用水不能集中下泄,导致水库水沙调控效益不明显。若需实现河道调水调沙任务,则应适当降低电站出力需求。研究成果为进一步缓解黄河上游水沙关系、制定水沙调控方案提供了科学合理的理论指导依据。

Discussion and analysis on concept and estimation of regulatable water volumes for sediment transport in the upper Yellow in different water demand scenarios

In recent years, the upper Yellow sees a situation that the relationship of water and sediment is deteriorating and increasingly more reaches of desert strath are shrinking due to sediment deposition, which has affected the safety of ice prevention and the comprehensive development and utilization of water resources. Joint regulation of the cascade reservoirs in this basin is one of the effective technical countermeasures for slowing down sediment accumulation, achieving more water-sediment regulation benefit, and improving the flow capacity of river channel in the dangerous reaches. This paper presents a preliminary analysis on the concept of regulatable sediment transport-required (STR) water volume in the upper Yellow, and a discussion on the relationship of this STR volume versus regulatable water volume. Using these two concepts, we calculated the regulatable water volume of the Longyangxia reservoir during 1987~2010, and analyzed the STR volume and the benefits of reservoir water-sediment regulation for the historical years, for two scenarios of satisfying comprehensive water utilization demand and satisfying power generation water demand. Results show that in the first scenario the Longyangxia's surplus water volume can completely meet the water demand by sediment transport and in the second scenario the regulation benefit is not significant owing to the scattered water discharges by power generation. This reveals that for this reach, a suitable reduction in its power generation demand is favorable in terms of satisfying its water-sediment regulation demand. This work would supply a basis for decision-making on how to improve water-sediment relationship and how to implement water-sediment regulation in the upper Yellow.