The Santa Cruz Channel is part of the Itamaracá–Itapessoca estuarine system in Brazil’s Northeast region. It presents a complex geometry and receives the debouches of several small streams. Here we present an assessment of the hydrodynamics of the Santa Cruz Channel and its role on the suspended sediment transport. A field campaign was carried out when water level, cross-sectional flow, current velocity and direction, salinity, and turbidity were recorded during a complete semi-diurnal tidal cycle during the peak of the wet period when the freshwater and river-borne suspended sediment are highest. Longitudinal distribution of salinity and turbidity were also recorded along a transect starting at the adjacent sea up to the upper estuary (salinity $=$ 0). Tides are the main driver of the transport processes, even considering that the observations were during the peak of the rainy season. The salinity displayed intra-tidal stratification, increasing to the low water and vanishing to the high water, which can be explained in terms of the tidal straining effect. So, the Santa Cruz channel behaves as a ‘Strained Induced Periodic Stratified’ (SIPS) system. The horizontal density gradient producing gravitational circulation seems to have a minor role in producing exchange flows. The suspended sediment input by the local river drainage dispersed along the systems displaying a conservative behavior. However, the hydrodynamic condition favors the retention of the river-borne sediment in the system, which has a high trapping efficiency.

圣克鲁斯海峡是巴西东北地区Itamaracá–Itapessoca河口系统的一部分。它呈现出复杂的几何形状，并接收多个小溪流的水流。在这里，我们对圣克鲁斯海峡的水动力及其在悬浮泥沙输送中的作用进行了评估。当在淡水和河流悬浮沉积物的湿润高峰期的一个完整的半日潮周期中记录了水位，横断面流量，水流速度和方向，盐度和浊度时，进行了野外活动。是最高的。盐度和浊度的纵向分布也沿一条样带记录，该样带从相邻海开始直至上河口（盐度）$=$0）。潮汐是运输过程的主要驱动力，即使考虑到观测值是在雨季的高峰期。盐度显示出潮汐内分层，增加到低水位并消失到高水位，这可以用潮汐应变效应来解释。因此，圣克鲁斯（Santa Cruz）频道的行为就像一个“应变诱导周期性分层”（SIPS）系统。产生重力循环的水平密度梯度似乎在产生交换流中的作用很小。当地河流排水输入的悬浮沉积物沿系统散布，表现出保守的行为。但是，水动力条件有利于系统中河床沉积物的保留，捕集效率高。