SPATIAL VARIABILITY OF SEDIMENT GENERATION AND CONNECTIVITY IN HPPS WATERSHEDS

Abstract The knowledge of the spatial variability of the generation and transport of sediments allows the identification with considerable precision critical areas regarding the generation and flow of detrital materials in watersheds. This paper aims to relate the spatial variability of soil loss and sediment connectivity in a contribution basin of the Batalha Hydroelectric Power Plant reservoir in the municipality of Cristalina (GO). The methodology comprised the bivariate spatial correlation between production estimates (MUSLE) and the Connectivity Index (CI) applied at a slope scale in the basin's contribution area. The results indicate the configuration of four spatial patterns: low production and low connectivity index in most of the area, comprising the higher and flatter portions; low production and high connectivity index in the vicinity of springs and drainage channels; high production and low connectivity index in the higher, steeper and more distant portions; and high production and high connectivity, predominating in the steepest portions and closest to the channels or even in those portions that are more distant but are connected to the channel, in the latter situation via more intense surface runoff flow lines. In this sense, the importance of this methodology is highlighted in the identification of critical areas, which are priority areas for the implementation of mitigating measures of the impacts resulting from hydric erosive processes.摘要：掌握沉积物产生与运移的空间变异特征，可精准识别流域内碎屑物质产生与运移的关键区域。本研究以位于戈亚斯州克里斯塔利纳市（Cristalina, GO）的巴塔尔哈水电站（Batalha Hydroelectric Power Plant）水库汇水区为研究对象，旨在探讨土壤侵蚀产沙与沉积物连通性的空间变异关系。研究方法采用在汇水区坡面尺度下开展的修正通用土壤流失方程（Modified Universal Soil Loss Equation, MUSLE）产沙量估算结果与连通性指数（Connectivity Index, CI）之间的二元空间相关性分析。研究结果识别出四类空间分布格局：一是研究区大部分区域呈现低产沙量与低连通性指数特征，对应地势较高且平坦的地块；二是泉眼与排水沟渠周边区域呈现低产沙量与高连通性指数特征；三是地势较高、坡度较陡且距河道较远的区域呈现高产沙量与低连通性指数特征；四是高产沙量与高连通性指数格局，主要分布在坡度最陡且临近河道的区域，或是虽距河道较远但通过强烈地表径流流线与河道连通的区域。综上，本研究方法可有效识别水力侵蚀过程所引发影响的关键区域，为相关减缓措施的落地实施提供优先整治方向。