甘肃省白龙江引调水工程受水区渭河与泾河流域年径流量演变情势

Evolution of Annual Runoff in the Wei and Jing River Watersheds in the Water-Receiving Areas of the Bailong River Water Diversion Project in Gansu Province

摘要: 随着人口增长和经济发展，干旱半干旱地区水资源供需矛盾日益突出，跨流域引调水工程被认为是解决这一问题最有效的解决手段之一，而引调水工程受水区的年径流量演变情势对规划引调水工程的规模与调度起着十分重要的作用。本研究以甘肃省白龙江引调水工程受水区为研究对象，利用CWatM模型模拟年径流量，结合1961~2020年实测年径流数据和未来SSP370气候情景，分析了研究区域内北道与杨家坪两个径流控制站的年径流包括突变点、演变趋势及其周期性在内的演化情势。研究结果表明：1) CWatM模型在模拟受水区所在流域的月尺度径流方面表现良好，率定期与验证期结果均可满足精度要求；2) 通过实测数据分析，表明北道与杨家坪站的年径流量在1992年和1985年分别发生突变，突变后径流量显著减少，通过趋势分析发现北道与杨家坪站年径流量突变前均呈现显著下降趋势，而突变后北道站呈显著上升趋势，杨家坪站逐渐趋于稳定，尽管该区域降水量有所增加，但蒸发量和耗水量的上升幅度更大，必导致水资源供需矛盾进一步加剧。周期性分析发现年径流量在短周期(2~8年)内存在波动，主周期为5年，无明显长周期；3) 在未来SSP370情景下，考虑人类取用水影响后，两站点年径流量均呈下降趋势，北道与杨家坪站的多年平均径流量分别减少19.9%和46.0%，因此，人类取用水显著影响径流总量与变化趋势，尤其是杨家坪站所在的泾河流域，亟需通过外流域调水缓解当地水资源压力。

Abstract: With population growth and economic development, the contradiction between water supply and demand in arid and semi-arid regions has become increasingly prominent. Inter-basin water diversion projects are considered to be one of the most effective solutions to this contradiction. The evolution of annual runoff in the receiving area of water diversion projects plays a crucial role in planning the scale and regulation of such projects. This study focuses on the evolution of annual runoff in the watersheds of the water-receiving areas of the Bailong River Water Diversion Project. Taken the receiving area of the Bailong River Water Diversion Project in Gansu Province as a case study, the measured annual runoff data from 1961~2020 was used to calibrate and verify the CWatM model. And the results by SSP370 future climate scenarios are from the CWatM model. Beidao and Yangjiaping are located in the Wei and Jing river watersheds, respectively. And the abrupt change points, evolution trends, and periodicity of the annual runoff are identified in these two stations. The results indicate that: 1) The CWatM demonstrates satisfactory performance in simulating monthly runoff within the water-receiving area, with both calibration and validation periods meeting prescribed accuracy criteria; 2) Abrupt changes in annual runoff were found in 1992 at Beidao station and in 1985 at Yangjiaping station. There were significant downward trends of the annual runoff at both Beidao and Yangjiaping stations before the abrupt change while there was a significant upward trend at Beidao station and a stationary trend at Yangjiaping station. Although there was an increase in precipitation, there were more increases in evaporation and in water consumption. The contradiction between water supply and demand inevitably was exacerbating. There were short periodicities with 2~8 years and without significant long periodicities at the two stations; 3) Under the future SSP370 scenario, the annual runoffs at both stations show the decreasing trends, and the multi-year average runoff had been found to be decreased 19.9% and 46.0%. Our study demonstrates that water supply significantly affects the total runoff and its trends, especially in the Jinghe River Basin where Yangjiaping station is located, urgently requiring inter-basin water transfer to alleviate local water resource pressure.