By discharging excess stormwater at rates that more frequently exceed the critical flow for stream erosion, conventional detention basins often contribute to increased channel instability in urban and suburban systems that can be detrimental to aquatic habitat and water quality, as well as adjacent property and infrastructure. However, these ubiquitous assets, valued at approximately $600,000 per km² in a representative suburban watershed, are ideal candidates to aid in reversing such cycles of channel degradation because improving their functionality would not necessarily require property acquisition or heavy construction. The objective of this research was to develop a simple, cost‐effective device that could be installed in detention basin outlets to reduce the erosive power of the relatively frequent storm events (~ < two‐year recurrence) and provide a passive bypass to maintain flood control performance during infrequent storms (such as the 100‐year recurrence). Results from a pilot installation show that the Detain H₂O device reduced the cumulative sediment transport capacity of the preretrofit condition by greater than 40%, and contributed to reduced flashiness and prolonged baseflows in receiving streams. When scaling the strategy across a watershed, these results suggest that potential gains in water quality and stream channel stability could be achieved at costs that are orders of magnitude less than comparable benefits from newly constructed stormwater control measures.

中文翻译：

---

拘留出口的改造通过减少接收通道中的侵蚀性流动来改善现有拘留盆地的功能。

传统的滞留盆地通过以超出溪流侵蚀临界流量的速率排放过量的雨水，常常导致城市和郊区系统中河道的不稳定性增加，这可能对水生生境和水质以及邻近的财产和基础设施不利。但是，这些无处不在的资产，每公里^2的价值约为600,000美元。在有代表性的郊区流域中，是理想的候选人，可以帮助扭转这种渠道退化的循环，因为改善其功能并不一定需要获得财产或进行繁重的建设。这项研究的目的是开发一种简单，具有成本效益的设备，可以将其安装在滞留池出口中，以减少相对频繁的暴风雨事件的侵蚀力（〜小于两年的复发），并提供被动旁路来维持洪水在罕见风暴（例如100年复发）中控制性能。试点安装的结果表明，Detain H ₂O装置将改造前条件下的累积泥沙输送能力降低了40％以上，并有助于减少了闪蒸和延长了接收流中的基流。当在整个流域范围内扩展该策略时，这些结果表明，可以以比新建雨水控制措施的可比收益少几个数量级的成本获得水质和河道稳定性的潜在收益。