郭城驿流域水沙演变对降水和水保措施的响应

周蕊 张富 李晓雅 靳峰 胡彦婷 赵秀兰

摘 要：為了解半干旱黄土区降水量、径流量和输沙量的演变规律，给当地水利水土保持工作提供理论支持和技术指导，以郭城驿流域为研究对象，采用泰森多边形法计算流域面平均降水量，采用Mann-Kendall检验法分析年降水量、年径流量、年输沙量的变化趋势，采用Morlet小波分析年降水量、年径流量和年输沙量的变化周期，采用多元功效函数（幂函数）模型对年径流量、年输沙量与年降水量、流域治理程度的关系进行回归分析。结果表明：1957—2016年郭城驿流域年降水量存在16～32 a、6～16 a和3～6 a等3种时间尺度的周期性变化，研究时段内整体上呈不显著减少趋势;年径流量和输沙量均存在16～32 a、6～12 a和3～6 a等3种时间尺度的周期性变化，研究时段内整体上均呈显著减少趋势，年输沙量减幅大于年径流量减幅;年径流量、年输沙量随年降水量的增加而增加，随治理程度的提高而减小，年径流量、年输沙量与年降水量、流域治理程度成较好的幂函数关系，在年降水量减少趋势不显著的情况下年径流量和输沙量显著减少的主要原因是流域治理程度大幅度提高，尤其与连台化梯田建设、造林种草密切相关。

关键词：降水量;径流量;输沙量;水土保持措施;治理程度;水沙演变;郭城驿流域

中图分类号：P333;S157.2 文献标志码：A

doi：10.3969/j.issn.1000-1379.2021.05.022

Abstract： In order to understand the climate change trend （precipitation） and the process and mechanism of runoff and transportation of sediments in the Guochengyi watershed which is located in the semi-arid loess northern China and provide theoretical support and technical guidance for local soil and water conservation work， this study was aimed with the following objectives. In order to calculate the average rainfall of the basin area， Tyson polygon method was used. In addition， in order to find the climate change trend （annual precipitation） and analyze the annual runoff and annual sediment transport， Mann-Kendall test method was used in this study. Moreover， to estimate the dynamic cycle of rainfall， runoff and sediment transport annually， Morlet wavelet analysis was performed. Furthermore， regression analysis was done in order to check the multivariate function i.e. the relationship between runoff and sediment transportation annually with annual precipitation and treatment degree of river basin. The results show that the long-term annual precipitation in Guochengyi watershed from 1957 to 2016 has periodic changes in three-time scales of 16-32 a， 6-16 a and 3-6 a respectively. There is no significant reduction trend in the whole study period. The annual runoff and sediment transport have notably periodic changes in three-time scales of 16-32 a， 6-12 a and 3-6 a respectively. The consequences show that during the study period， the annual sediment discharge decreases significantly on the whole and the decrease of annual sediment discharge is greater than that of annual runoff. Additionally， the annual runoff and annual sediment transport increase with the increase of annual precipitation and decrease with the increase of control degree. The annual runoff and annual sediment transport have a strong relationship with annual rainfall and watershed treatment degree. The main reason for the noticeably reduction of annual runoff and sediment transport under the condition of non-significant annual precipitation reduction is that the degree of watershed management is greatly improved， especially closely related to the construction of terraced fields and afforestation and grass planting.

Key words： precipitation; runoff; sediment transport; soil and water conservation measures; treatment control; runoff and sediment evolution; Guochengyi watershed

半干旱区河流水沙与降水密切相关[1-4]。黄河以水少沙多而著称，在自然和人类活动的作用下，黄河干流径流量、输沙量显著减少[5-6]。在径流量和输沙量的量化分析中，不少学者认为人类活动对径流量、输沙量变化的贡献率呈增大趋势，是影响径流量、输沙量变化的主要驱动因子[7-14]。……