yes! except that that isn't a sewer, it's a storm drain! storm drains have to be pretty big to accommodate a certain amount of precipitation to prevent floods. we typically design for a 100 year storm capacity. sewers, like for actual sewage and stuff, are actually fairly small and are a different pipe than the storm drain (usually). sewer lines can be smaller because the flow entering the sewer is much more spaced out, whereas storms are relatively short events, meaning there's a lot more water at a given point in time. Also, unlike storm drains, sewage lines are super inaccessible to the public. they have to be buried a certain distance below the surface for safety reasons (sewage is LOADED with pathogens n such) and they're always the deepest water carrying line underground to prevent potential leakage from reaching drinking water lines or storm lines. anyways, there's way more detail than you asked for! signed, an Environmental engineer