Coastal erosion is a critical problem that affects several countries around the World that would increase concerning the anthropogenic sea-level rise. Gravel beaches have proved to be more stable facing coastal erosion. The mixture of sand and gravel has been used to replenish beaches as a soft mechanism that increases beach stability. Most of the Buenos Aires coastline is composed of sand, although some beaches are composed of mixed sand and gravel. These beaches vary spatially and temporally in the sand-gravel proportion; the gravel fraction is mainly composed of volcanic lithics derived from Patagonia, with caliche and bioclasts of local contribution. Six mixed sand and gravel beaches (MSGB) with diverse grain size and sand-gravel rates were monitored to evaluate the morphodynamic changes and grain-size variability in cross-shore profiles throughout a year (May 2016—April 2017). Also, the wave conditions were analyzed to identify high-energy wave events using ERA5 dataset. A general behaviour of the six beaches was discerned, where the gravel fraction increases significantly in the seasons with more high-energy wave events (autumn and spring), especially in the upper-foreshore. In these periods, the gravel-runs formation and the sediment armouring were described. In summer times, an increment in the accretion of the cross-shore profiles and sand fraction proportion were recorded. The increase of gravel proportion, gravel runs development and armouring processes are some responses of MSGB to high energy conditions that cause greater stability.

海岸侵蚀是一个严重的问题，影响到世界上几个国家，这些国家会因人为海平面上升而增加。事实证明，砾石海滩在面对海岸侵蚀时更稳定。沙子和砾石的混合物已被用来补充海滩，作为一种增加海滩稳定性的柔软机制。布宜诺斯艾利斯的大部分海岸线由沙子组成，尽管一些海滩由沙子和砾石混合而成。这些海滩的沙砾比例在空间和时间上都有所不同；砾石部分主要由源自巴塔哥尼亚的火山岩岩组成，并有当地贡献的钙质和生物碎屑。监测了六个具有不同粒度和砂砾率的混合砂砾海滩（MSGB），以评估全年（2016 年 5 月至 2017 年 4 月）跨海岸剖面的形态动力学变化和粒度变化。此外，还分析了波浪条件以使用 ERA5 数据集识别高能波浪事件。观察到六个海滩的一般行为，其中砾石分数在高能量波浪事件较多的季节（秋季和春季）显着增加，尤其是在上前滩。在这些时期，描述了砾石流形成和沉积物装甲。在夏季，记录了跨海岸剖面和砂粒比例的增加。砾石比重增加，