Living With Water

New Orleans’ understanding and relationship with water has changed dramatically over our 300 year history. The City has always contended with flooding from rainfall, and now faces new challenges, including changing climate, rising seas, and human-induced sinking of the land. The current approach to managing stormwater means that every drop of water that falls must be pumped out which leads to water and soil imbalances. Intelligent retrofits and a new approach to stormwater and groundwater management through an investment in comprehensive and innovative urban water management can reduce flooding and rates at which the region is sinking, and restore the identity of New Orleans as a preeminent place rich in public assets, industry, and innovation.

GREEN INFRASTRUCTURE:

Green infrastructure uses vegetation, soils, and natural processes to reduce risks from flooding and subsidence, improve water quality, and create other community benefits such as improved recreation, transportation, community gathering, neighborhood beautification, and economic development. Green infrastructure works together with the city’s existing drainage system of pipes and pumps and is a key part of New Orleans’ comprehensive approach to water management.

UNDERSTANDING THE ISSUE:

New Orleans was first settled on the natural levee along the Mississippi River, however as engineering technology improved former swampland was drained for development of areas that are up to 11 feet below sea level.
New Orleans is one of the rainiest cities in North America, receiving on average over 64 inches of rain per year. Our subtropical climate means that rain events are often fast and intense, sometimes in excess of 2-3 inches per hour.
The Hurricane & Storm Damage Risk Reduction System (HSDRRS) protects the City from storm surge during tropical events, but traps rainwater within the walls during normal rain events. This requires every drop of rain to be pumped over the walls if it can’t be absorbed into the ground.
The way we manage water inside the levees impacts our groundwater and ultimately the volume of our soils. Excess pumping leads to shrinking soils, lowering ground elevations in the face of rising seas.
A new approach to water management will designate space for water to wait for pumps to catch up during large rain events, recharge our groundwater to reduce subsidence, filter pollutants to improve water quality, and provide countless ecosystem, economic, and social benefits for the community.

ADDITIONAL RESOURCES:

Greater New Orleans Urban Water Plan: livingwithwater.com
Climate-Smart Cities Mapping Tool: https://web.tplgis.org/NOLA_CSC/

PROJECT: Water Quality Management

TIMELINE: Ongoing

OVERVIEW: New Orleans is densely developed, meaning much of the land surface is covered by buildings, pavement and compacted landscapes. These surfaces do not allow rain to soak into the ground which greatly increases the volume and velocity of stormwater runoff and concentration of pollutants which include:

Sediment

Oil, grease and toxic chemicals from motor vehicles

Pesticides and nutrients from lawns and gardens

Viruses, bacteria and nutrients from pet waste

Heavy metals from roof shingles, motor vehicles and other sources

Thermal pollution from impervious surfaces such as streets and rooftops

All stormwater in New Orleans is discharged into Lake Pontchartrain on the Eastbank and the Mississippi River on the Westbank, both of which are critical natural waterbodies where polluted runoff can harm fish and wildlife populations, kill native vegetation, and make recreational areas unsafe and unpleasant.

To address polluted runoff from urban areas, the City of New Orleans is subject to the requirements of the Municipal Separate Storm Sewer System (MS4) permit (No. LAS000301) issued by USEPA Region VI. The permit was created by the USEPA under the National Pollutant Discharge Elimination System (NPDES) to address the water quality issues associated with the storm water runoff from the drainage areas included in the MS4 permit.

BENEFITS:

Improved health

Safe recreation

Clean drinking water

Reduced flooding

Wildlife habitat preservation

Protection of fisheries

FAQ:

How is stormwater treated before entering Lake Pontchartrain?

The frequency and intensity of rainfalls in New Orleans mean it is impossible to treat stormwater before it is pumped out of the city. The various SWBNO pump stations screen runoff for trash to prevent the debris from entering pumps; however citizens should assume that any debris that enters a catch basin will end up in the Lake. Preventing illicit discharges and promoting green infrastructure to filter runoff at the source is the best way to reduce pollutants in the runoff at discharge.

What are the City’s regulatory requirements for stormwater?

The federal Clean Water Act requires large and medium sized towns across the United States to take steps to reduce polluted stormwater runoff. The law was applied in two phases. The first phase addressed large cities. The second phase, often referred to as ”Phase II,” requires medium and small cities, fast growing cities and those located near sensitive waters to take steps to reduce stormwater. In Louisiana, Phase II laws took effect in 2003. These laws require chosen cities to do six things:

Conduct outreach and education about polluted stormwater runoff.

Provide opportunities for residents to participate and be involved in conversations and activities related to reducing polluted stormwater runoff.

Detect illicit discharges (e.g. straight piping or dumping).

Control construction site runoff.

Control post-construction runoff.

Perform municipal housekeeping (e.g. take steps to prevent runoff from city buildings and activities.)

If stormwater runoff only affects the Lake, why should I care?

Lake Pontchartrain is as estuary which leads to the Gulf of Mexico. If you like to fish, swim or boat, you may have heard or been affected by advisories warning you not to swim, fish or boat in the Lake, wetlands, or Gulf because of unhealthy water or too much algae. Seafood like shrimp and oysters cannot be harvested from polluted waters, so anyone that enjoys these foods or makes a living from the seafood industry is affected. Tourism and water recreation can also be impacted, as are businesses and home flooded by stormwater runoff. When we pollute our water, everyone is affected!

Who do I call if I see someone dumping waste or materials into a catch basin?

You can call the Sewerage and Water Board at 52-WATER or the City of New Orleans by dialing 3-1-1 within the City of New Orleans to report dumping in a catch basin.

FOR MORE INFO: Tyler Antrup, Urban Water Program Manager tjantrup@nola.gov

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