Beaches are dynamic systems characterized by frequent morphological changes due to storm events, gradients in longshore sediment transport, seasonal variations in wave climate and more. The complexity of variations in beach morphology can increase significantly after a beach nourishment, particularly when coastal structures are involved. This study investigates the impacts of a groin field, consisting of both notched and traditional groins, on the morphological evolution of a beach in Deal, New Jersey, USA. More specifically, an evaluation of the performance and specifications of the notched groins is undertaken. In 2016, the beach in Deal was nourished and three of the eight groins comprising the groin field were concurrently notched in order to promote increased movement of longshore sediment transport while maintaining a stable shoreline. The study site was monitored nine times over a period of two years (2018–2019) using Unmanned Aerial Systems Structure from Motion (UAS-SfM) photogrammetry. The near-term morphological response of the study site was evaluated by analyzing high-resolution digital elevation models (DEMs) and longshore sediment transport estimates based on measured wave data.

The elevation change maps established that in general, the groin notching was partially successful in reducing shoreline asymmetry in consequence of sediment transport bypassing through the notches. Differences in behavior and patterns of elevation change adjacent to each individual notched groin was observed even though they were all notched according to the same specifications. While all three notched groins were effective in stabilizing the adjacent shoreline, they varied in their effectiveness at promoting longshore sediment transport through the notch. This is likely attributable to the relative location of the notched groins within the groin field and the characteristics of the post-nourishment morphological evolution; the direction of net annual longshore sediment transport at Deal beach is northward, which caused the southern areas of the study site to narrow and the northern areas of the study site to widen. Consequently, the notched groins in the wider sections of beach did not function as intended, as the notches filled in with sediment causing them to mimic the behavior of a traditional groin, including restricted longshore sediment transport and significant erosion/accretion offsets. In the narrower section of beach, the notched groin functioned as designed, such that the notch was located in the swash zone and therefore allowed bi-directional sediment transport and maintained a stable and relatively symmetrical shoreline. Thus, the notched groins performed most effectively when the notch was consistently located toward the seaward end of the swash zone.

海滩是动态系统，其特征是由于风暴事件、沿岸沉积物输送的梯度、波浪气候的季节性变化等而导致频繁的形态变化。在海滩滋养后，海滩形态变化的复杂性会显着增加，尤其是在涉及沿海结构时。本研究调查了腹股沟部位（由缺口腹股沟和传统腹股沟组成）对美国新泽西州迪尔海滩形态演变的影响。更具体地说，对带缺口的腹股沟的性能和规格进行了评估。2016 年，Deal 的海滩得到滋养，构成腹股沟区的 8 个腹股沟中的 3 个同时开槽，以促进沿岸沉积物运输的增加，同时保持稳定的海岸线。在两年（2018 年至 2019 年）期间，使用无人机运动系统结构 (UAS-SfM) 摄影测量对研究地点进行了九次监测。通过分析高分辨率数字高程模型 (DEM) 和基于实测波浪数据的沿岸沉积物输移估计，评估了研究地点的近期形态响应。

高程变化图表明，一般来说，腹股沟切口部分成功地减少了由于沉积物运输绕过切口而导致的海岸线不对称。尽管每个切口腹股沟的切口均按照相同的规格进行，但仍观察到与每个切口腹股沟相邻的行为和高度变化模式的差异。虽然所有三个带缺口的腹股沟都有效地稳定了相邻的海岸线，但它们在促进沿海沉积物通过缺口输送方面的效果各不相同。这可能是由于腹股沟区域内有缺口的腹股沟的相对位置以及营养后形态演变的特征；Deal海滩的年净岸边泥沙输移方向为北，这导致研究地点的南部区域变窄，而研究地点的北部区域变宽。因此，海滩较宽部分的带缺口的腹股沟没有按预期发挥作用，因为缺口充满了沉积物，导致它们模仿传统腹股沟的行为，包括受限制的沿岸沉积物运输和显着的侵蚀/堆积偏移。在海滩较窄的部分，槽口腹股沟按设计功能发挥作用，槽口位于倾斜带，因此允许泥沙双向输送，并保持稳定和相对对称的海岸线。因此，当切口始终位于倾斜区的向海端时，切口腹股沟的表现最有效。海滩较宽部分的槽口腹股沟没有按预期发挥作用，因为槽口充满了沉积物，导致它们模仿传统腹股沟的行为，包括受限制的沿岸沉积物运输和显着的侵蚀/堆积抵消。在海滩较窄的部分，槽口腹股沟按设计功能发挥作用，槽口位于倾斜带，因此允许泥沙双向输送，并保持稳定和相对对称的海岸线。因此，当切口始终位于倾斜区的向海端时，切口腹股沟的表现最有效。海滩较宽部分的槽口腹股沟没有按预期发挥作用，因为槽口充满了沉积物，导致它们模仿传统腹股沟的行为，包括受限制的沿岸沉积物运输和显着的侵蚀/堆积抵消。在海滩较窄的部分，槽口腹股沟按设计功能发挥作用，槽口位于倾斜带，因此允许泥沙双向输送，并保持稳定和相对对称的海岸线。因此，当切口始终位于倾斜区的向海端时，切口腹股沟的表现最有效。包括受限制的沿岸沉积物运输和显着的侵蚀/堆积抵消。在海滩较窄的部分，槽口腹股沟按设计功能发挥作用，槽口位于倾斜带，因此允许泥沙双向输送，并保持稳定和相对对称的海岸线。因此，当切口始终位于倾斜区的向海端时，切口腹股沟的表现最有效。包括受限制的沿岸沉积物运输和显着的侵蚀/堆积抵消。在海滩较窄的部分，槽口腹股沟按设计功能发挥作用，槽口位于倾斜带，因此允许泥沙双向输送，并保持稳定和相对对称的海岸线。因此，当切口始终位于倾斜区的向海端时，切口腹股沟的表现最有效。