Flow pattern at a river diffluence at the alluvial system of the Paraná River

This communication presents field and numerical data depicting the flow pattern formed at a diffluence of the Colastiné River, Argentina, where one branch accesses the local harbour. The harbour has been in decline since the 1970s due to costly maintenance dredging of the access channel. The objective of this work is thus twofold: to show the persistence of the flow pattern developed at the diffluence despite recent morphological changes seen at the site, and to test a possible solution to the access channel sedimentation problem. Knowledge gained during the execution of the study helped to validate a code developed to process field data captured with two acoustic Doppler current profilers (ADCPs). The results confirm that both branches are prone to developing secondary currents. Simulations show that an engineering intervention downstream of the bifurcation can establish a self-dredging flow reversal along the access channel, turning the actual diffluence into a stable confluence.

本数据集收录了阿根廷科拉斯蒂内河（Colastiné River）分流口处的实测与数值模拟数据，用以刻画该分流区域形成的水流流态——其中一条支汊通往当地港口。该港口自20世纪70年代起，便因进港航道维护疏浚成本高昂而持续衰落。本研究的目标兼具双重性：其一，验证尽管该区域近期发生了地貌形态变化，分流口处的水流流态仍可保持稳定；其二，针对进港航道的泥沙淤积问题，测试一种可行的解决方案。本研究过程中获得的认知，验证了一款用于处理两台声学多普勒流速剖面仪（acoustic Doppler current profilers, ADCP）采集的实测数据的数值分析代码。模拟结果表明，在分流口下游实施工程干预，可在进港航道沿线形成可自疏浚的反向流态，将实际存在的分流口改造为稳定的汇流区域。