DAGVATTENINLÄCKAGE GENOM SPILLVATTENNÄTETS BRUNNSBETÄCKNINGAR / Urban Stormwater Leakage Through Sewer Manhole Covers
The flow of water which leaks in through sewer manhole covers was estimated by experiments. During storms or periods of snow-melt, the volume of water leaking in through these manholes may increase the flow in the sewers substantially, resulting in an increased risk of secondary damage. The variations in water flow leaking through the key-holes or the periphery of two different covers, as a consequence of a range of water surface levels above the covers, was estimated experimentally. The flow reached 2.5 l/s at 2 cm of water height and 3.2 l/s at 4 cm of water height when both the periphery and the key-holes of one cover were open. When its periphery was sealed, the corresponding flows were 0.7l/s and 1 l/s respectively.