Stormwater management ponds are common best management practice (BMP) and green infrastructure (GI) for flood attenuation and water quality treatment in highway projects. Originally designed to provide storage volume for flood detention, stormwater ponds today often employ additional retention volume at pond bottom in a hope to improve water quality via sedimentation and other pollutant-removal mechanisms. It is commonly assumed that sediment accumulation and topographic variations (such as erosion, channelization, and in-pond plant growth and decay) over time often decrease the capacity of stormwater ponds. However, differences between design capacities and field capacities over time have never been verified and quantitatively analyzed before. This study presents such analysis using conventional topographic survey techniques and remote sensing data (topographic light detection and ranging digital elevation model [LIDAR DEM]) for 10 highway stormwater ponds along Interstate Highway-95 (I-95) systems in Baltimore City, Cecil County, and Harford County, Maryland, United States, with facility service life ranging from 14 to 26 years (1990–2015). Data derived from LIDAR DEM were compared with those from topographic survey; the LIDAR DEM data appear to be effective in measuring flood detention capacities and identifying silted ponds, but not in estimating the remaining retention volume for water quality treatment. Data from topographic survey indicate that the total volume in the ponds was relatively unchanged compared with the design, with increases in some instances. The increase typically occurred at the pond’s upper stages. Nonetheless, the water quality treatment capacity at pond bottom (wet pool volume) was drastically less (up to 100% of the design). As current maintenance practice of stormwater ponds relies heavily on visual inspection, the storage volume variations are often overlooked. As such, the findings prompt uncertainty on the long-term effectiveness of watershed implementation plan and models in the Chesapeake Bay watersheds, as many of them depend on wet pool volume design in BMP and GI.

雨水管理池塘是公路项目中减洪和水质处理的常见最佳管理实践（BMP）和绿色基础设施（GI）。最初设计用于提供蓄洪量的蓄水池，如今的雨水池塘经常在池塘底部使用额外的蓄水池，以期通过沉淀和其他污染物去除机制来改善水质。通常认为，随着时间的流逝，沉积物的积累和地形变化（例如侵蚀，渠道化以及池塘中的植物生长和腐烂）通常会降低雨水塘的容量。然而，设计能力和现场能力之间的差异随着时间的流逝从未得到验证和定量分析。本研究使用常规地形调查技术和遥感数据（地形光检测和测距数字高程模型[LIDAR DEM]），对塞西尔县巴尔的摩市沿州际95号公路（I-95）系统的10个高速公路雨水塘进行了分析和美国马里兰州哈福德县，设施使用寿命为14到26年（1990-2015年）。将来自LIDAR DEM的数据与来自地形调查的数据进行了比较；LIDAR DEM数据似乎可以有效地测量洪水的滞留能力和识别淤积的池塘，但不能估计水质处理的剩余滞留量。地形调查的数据表明，与设计相比，池塘的总体积相对不变，在某些情况下有所增加。这种增加通常发生在池塘的上游。尽管如此，池塘底部（湿池容积）的水质处理能力却大大降低（达设计的100％）。由于当前雨水塘的维护实践主要依靠目视检查，因此往往忽略了存储量的变化。因此，研究结果提示切萨皮克湾流域的流域实施计划和模型的长期有效性存在不确定性，因为其中许多依赖于BMP和GI中的湿池容积设计。