New Orleans Drainage
The low elevation of New Orleans makes drainage of the city a difficult problem. Water has to be removed by pumps from the metropolitan section of the city, which is protected from outside high water by encircling levees. Ten pumping stations and more than 870 miles of drainage canals and pipelines have been installed for that purpose. Underground tributary canals, fed by gutters and drainpipes, lead the water into the main system, from which it is pumped into Bayou Bienvenue and flows by gravity into Lake Borgne. An additional safety measure is provided for in the Bonnet Carré Spillway, which makes possible the diversion into Lake Pontchartrain of Mississippi flood waters at a point twenty miles above New Orleans.