Other manhole shapes can be found, usually squares or rectangles. For example, in the United Kingdom nearly all manhole covers are square or rectangular and very occasionally triangular, but almost never circular. Nashua, New Hampshire, is unusual for having triangular manhole covers that point in the direction of the underlying flow. In 2011, the city began gradually phasing out the triangles,[9] which were made by a local foundry, because they were not large enough to meet modern safety standards and a manufacturer for larger triangles could not be found.[10] Some manhole covers in Hamilton, Bermuda, are triangular, and hinged. Some triangular water-main covers also exist in San Francisco.[11]
Scupper drain grating refers to the covering installed over a scupper drain, which is typically located at the edge of a rooftop, balcony, or paved area. The primary purpose of the scupper is to direct rainwater away from critical areas and into a controller drainage system, thereby preventing water accumulation that could lead to structural damage or flooding. The grate serves as a barrier, ensuring that larger debris—such as leaves, twigs, and trash—does not enter the drain, which could result in blockages.
In conclusion, hydraulic manhole covers are not merely access points to subterranean utilities; they are a critical component of contemporary urban infrastructure. By prioritizing safety, efficiency, and aesthetic integration, they stand as a testament to the ongoing advancements in urban planning and engineering. As cities face the challenges of an ever-changing environment, hydraulic manhole covers will continue to play a pivotal role in shaping the future of urban living.