Groundwater drainage in New Orleans

Abstract

The goal of this study was to get a better understanding of the current groundwater drainage in New Orleans, Louisiana. An analysis was conducted on the interactions between groundwater drainage and different water infrastructure systems like: the sanitary sewer system, the storm water drainage system, and the drinking water system. Due to the age of these networks, damage caused during natural disasters like Hurricane Katrina, the ground movement sensitivity of the region and the existing land subsidence, these networks are in poor shape. To quantify the groundwater drainage component of each system, an existing QGIS wastewater model was used along with different time series, including hourly and daily data for precipitation and sewer station influents, and a storm drainage analysis based on pumping station data. The following notable conclusions per water system were made: 1) 50% of the total water treated in the wastewater treatment plant is groundwater, adding a large amount of unnecessary stress to the treatment process, 2) the storm water drainage system is the largest groundwater drainage component contributing to 58% of the total groundwater drainage and 3) 55% of the produced drinking water is lost during distribution, meaning the drinking water losses are a larger groundwater recharge than the annual precipitation surplus. A large part of this lost drinking water is then drained by the adjacent sewer and storm water drainage pipes.