We have (create?) a similar problem every time it rains heavily. Like many places, we have combined sewers (storm and sanitary) so with heavy rain, the flow exceeds the capacity of the Sewage Trea----- uh, Water Reclamation Facility, and the overflow goes right into the Cuyahoga River. Our own drinking water comes from upstream, but our waste then goes down to Lake Erie, where if it doesn't directly contaminate drinking water supplies, it feeds algal blooms that will. Over recent years, we've built many massive stormwater retention basins, and a tunnel boring machine (named Rosie, and she got a local beer named for her) is just emerging after building a mile-plus long one. The problem is that development of land, leading to runoff into the storm sewers instead of absorption into soil, seems to outpace these measures, while storms keep getting wetter.