Millions of cubic meters of water are lost every year from water utilities, with detrimental consequences on the environment and on society. However, this large amount of water is not necessarily lost. Although leaking water utilities have the potential to recharge urban aquifers, very little is known about the fate of leaked water and its interaction with subsurface anthropogenic features, such as the high permeability trenches surrounding utility pipelines. As these features are deemed to create preferential pathways, it is crucial to understand if these can reduce urban aquifers recharge by interception and diversion of water leaked. Through a series of transient 3D numerical simulations under a variety of conditions (i.e., different native soil properties, slopes of the utility trench, depths of the groundwater table, and leak rates), this study provides evidence that utility trenches can potentially alter the migration pathway of water leaked from utility pipelines located above the groundwater table. Therefore, the urban karst effect has the potential to occur directly at the utility trench. Indeed, from roughly 55% up to 73% of the water leaked is retained within the utility trench and does not reach the underlying aquifer in one third of the scenarios modeled. This occurs because of the combined effect of soil retention properties, initial effective water saturation, relative permeability, and intrinsic permeability. Although this analysis is still preliminary, these results potentially challenge the traditional concept of leaking pipes recharging groundwater.

每年有数百万立方米的水从供水设施中流失，对环境和社会造成不利影响。然而，这种大量的水并不一定会流失。尽管漏水公用设施有可能给城市含水层补水，但对漏水的去向及其与地下人为特征（例如公用事业管道周围的高渗透性沟渠）的相互作用知之甚少。由于这些特征被认为创造了优先路径，因此了解这些特征是否可以通过截留和分流泄漏的水来减少城市含水层的补给至关重要。通过一系列不同条件下的瞬态 3D 数值模拟（即不同的原生土壤特性、公用沟坡度、地下水位深度和泄漏率），这项研究提供的证据表明，公用事业沟渠可能会改变从位于地下水位以上的公用事业管道泄漏的水的迁移途径。因此，城市岩溶效应有可能直接发生在公用事业沟渠。事实上，在三分之一的模拟情景中，大约 55% 到 73% 的泄漏水保留在公用事业沟渠内，并没有到达底层含水层。这是由于土壤保持特性、初始有效水饱和度、相对渗透率和固有渗透率的综合影响。尽管该分析仍处于初步阶段，但这些结果可能会挑战泄漏管道补给地下水的传统概念。