The shallow, turbid water of the Delaware Bay Estuary is the second most navigated waterway in the USA behind the Mississippi River and experiences tropical and extratropical cyclones from June through April bringing high winds, storm surge, precipitation, and coastal change. Mapping coastal areas within the Delaware Bay is particularly difficult due to inherent environmental factors such as low underwater visibility (less than 1 m), rapid tidal current (greater than 1 m/s), changeable weather, and strong mid-latitude winds. This study utilized four sonar systems, two manned vessels, two autonomous vessels, three real-time kinematics global positioning systems (RTK GPS), two unmanned autonomous aerial systems, and satellite imagery to quantify subaerial and subaqueous volume and feature changes following storm events. The study site was located at Broadkill Beach, Delaware, a microtidal beach inside the Delaware estuary and outside the National Coastal Mapping Program survey area. Six storms (four tropical and two extratropical cyclones) from 2012 to 2018 were surveyed pre- and post-storm. Key insights in sensors and platforms proved unmanned aerial systems (UAS) orthomosaic resolution to be superior for mapping shoreline, profile, and dune toe changes, swash zone features such as cusps, wrack lines, and infrastructure damage to beach crossovers. Subaqueous platforms performed well for most storm events with RMSE of 0.23 m or less. This uncertainty, including subaerial uncertainty (max = 0.016 m), can be reduced with precise GPS systems and ground truthing of elevations through additional sensors like RTK GPS and subbottom profilers. No clear pattern emerged between accretion and erosion for tropical or extratropical cyclones (TC or ETC). Low-energy beaches are rarely studied and therefore open-coast relationships are transplanted to these environments. Storm responses of the site did not match expected traditional cross-shore transport models as beach orientation and storm wind direction most likely induced longshore transport out of the system. UAS orthomosaics were critical in identifying wrack lines and debris which altered subaerial transport patterns at this low-energy site. This work highlights the importance of irregular, small-scale features such as relic jetties, wrack lines, and local wind waves in estuarine sites when traditional open-coast theory would diminish these processes. More importance should be placed on the use of high-resolution imagery and elevation data over widely spaced profiles when monitoring and managing low-energy sites experiencing episodic storms such as TC and ETC to accurately assess processes, relationships, and morphologic response.

特拉华湾河口浅而浑浊的水是美国仅次于密西西比河的第二大航道，从 6 月到 4 月会经历热带和温带气旋，带来强风、风暴潮、降水和海岸变化。由于固有的环境因素，如水下能见度低（小于 1 m）、快速潮流（大于 1 m/s）、多变的天气和强中纬度风，绘制特拉华湾内的沿海地区特别困难。本研究利用四个声纳系统、两艘载人船只、两艘自主船只、三个实时运动学全球定位系统 (RTK GPS)、两个无人驾驶自主航空系统和卫星图像来量化风暴事件后的水下和水下体积和特征变化。该研究地点位于特拉华州布罗德基尔海滩，这是一个位于特拉华河口内的微潮海滩，位于国家海岸测绘计划调查区之外。在风暴前后对 2012 年至 2018 年的六场风暴（四个热带气旋和两个温带气旋）进行了调查。传感器和平台的关键见解证明，无人机系统 (UAS) 正射镶嵌分辨率在绘制海岸线、剖面和沙丘坡脚变化、诸如尖头、残骸线和基础设施对海滩交叉口的破坏等方面具有优越的性能。对于 RMSE 为 0.23 m 或更低的大多数风暴事件，水下平台表现良好。这种不确定性，包括空中不确定性（最大 = 0.016 m），可以通过精确的 GPS 系统和通过额外的传感器（如 RTK GPS 和海底剖面仪）对高程进行地面实测来降低。热带或温带气旋（TC 或 ETC）的吸积和侵蚀之间没有出现明确的模式。很少研究低能量海滩，因此将开放海岸关系移植到这些环境中。该站点的风暴响应与预期的传统跨岸运输模型不匹配，因为海滩方向和风暴风向很可能导致沿岸运输离开系统。UAS 正射镶嵌技术对于识别在这个低能量地点改变空中运输模式的残骸线和碎片至关重要。这项工作强调了河口遗址中不规则、小尺度特征的重要性，例如遗迹码头、残骸线和局部风浪，而传统的开阔海岸理论会削弱这些过程。