Query: Who created Paris' reservoir system?
Context: From 1809, the Canal de l'Ourcq provided Paris with water from less-polluted rivers to the north-east of the capital. From 1857, the civil engineer Eugène Belgrand, under Napoleon III, oversaw the construction of a series of new aqueducts that brought water from locations all around the city to several reservoirs built atop the Capital's highest points of elevation. From then on, the new reservoir system became Paris' principal source of drinking water, and the remains of the old system, pumped into lower levels of the same reservoirs, were from then on used for the cleaning of Paris' streets.