Coastal zones are dynamic spaces where human activities and infrastructure are exposed to natural forces, climate change and extreme weather events such as storm surges. Coastal inundation is regarded as one of the most dangerous and destructive natural hazards, and while there are many studies to analyse these events, GIS based methods are limited. This research aimed at developing a GIS based enhanced Bathtub Model (eBTM) that improves on the widely used simple Bathtub Model (sBTM) to make it more appropriate to a storm surge related coastal inundation context. The eBTM incorporates beach slope, surface roughness and instils hydrological connectivity relevant for event scale coastal flooding, unlike the sBTM which only uses topographic elevation above sea level as input. For a test site in Cape Town, South Africa, inundation levels for 3 independent scenarios were calculated using the average spring tides level, extreme sea level for a 1-in-100-year storm and two sea-level rise scenarios. Each scenario was run on both the sBTM and the eBTM developed through this study. Comparing the results, the eBTM method overall produced more conservative inundation results and also produced less disconnected areas of (unrealistic) inundation. The eBTM also produces inundation water levels relative to structures, thus showing the potential for quantifying the coastal inundation risk to infrastructure, which is of relevance in the disaster response context. Additionally, the impact of using Digital Terrain Models (DTMs) instead of Digital Surface Models (DSM) on the inundation results was tested. The use of a DSM, including buildings and other objects, showed more realistic trajectories of the inundation water moving through the model area.

中文翻译：

---

对基于GIS的浴缸模型和增强型浴缸模型进行沿海淹没的比较评估

沿海地区是人类活动和基础设施受到自然力量，气候变化和风暴潮等极端天气事件影响的动态空间。沿海淹没被认为是最危险和最具破坏力的自然灾害之一，尽管有许多研究来分析这些事件，但基于GIS的方法仍然有限。这项研究旨在开发基于GIS的增强型浴盆模型（eBTM），该模型在广泛使用的简单浴盆模型（sBTM）的基础上进行了改进，使其更适合与风暴潮相关的沿海淹没环境。与仅使用海平面以上地形作为输入的sBTM不同，eBTM包含了与事件规模沿海洪水有关的海滩坡度，表面粗糙度和井下水文连通性。对于南非开普敦的测试站点，使用平均春季潮汐水平，100年1年风暴中的极端海平面以及两个海平面上升情景来计算3个独立情景的淹没水平。通过本研究开发的sBTM和eBTM都运行了每种方案。比较结果，eBTM方法总体上产生了更保守的淹没结果，并且产生的（不切实际的）淹没区域更少。eBTM还会产生相对于建筑物的淹没水位，因此显示了量化沿海淹没对基础设施的风险的潜力，这与灾难响应环境相关。此外，还测试了使用数字地形模型（DTM）代替数字表面模型（DSM）对淹没结果的影响。DSM的使用，包括建筑物和其他物体，