ASCE: American Society of Civil Engineers is a professional trade association that represents more than 139,000 civil engineers worldwide and is America's oldest national engineering society. ASCE provided an external peer review of IPET’s study.

Base Flood: a flood that has a 1% chance of occurring (or exceeded) in any given year. Often called the 100-year flood.

Base Flood Elevation (BFE): a geographic elevation that has a 1% chance of being flooded (or exceeded) in any given year by a base flood.

Breach: When a levee or structure loses its normal crest elevation (fails). A breach can be a 1 ft depression or a big gap in a levee. Breaches can occur through erosion or foundation failure; water flows through the breach until it equalizes (a breach causes much deeper water than simple overtopping).

Consequence: The direct affect of the event. It is expressed as a health effect (i.e., loss of life), or property loss.

Erosion: When water washes away material critical to a levee or structure’s stability, usually on the back side of the levee as a result of overtopping

FEMA: Federal Emergency Management Agency manages federal response and recovery efforts following any national incident. FEMA also initiates mitigation activities, works with state and local emergency managers, and manages the National Flood Insurance Program.  FEMA became part of the U.S. Department of Homeland Security on March 1, 2003.

Hazard: Surge and waves created by hurricanes

Hurricane Protection System: levees, floodwalls, pumps, gates, etc., all working together

IHNC: The Inner Harbor Navigation Canal and Lock, located within the limits of the city of New Orleans was completed by the Port of New Orleans in 1923. The five-mile canal was completed to provide navigation between the Mississippi River and Lake Pontchartrain in addition to stimulating industrial development in areas away from the Mississippi River. During World War II the Gulf Intracoastal Waterway (GIWW) was rerouted through the Industrial Canal, and the Federal Government subsequently assumed its operation and maintenance, ultimately purchasing the lock in 1986.

IPET: Stands for the Interagency Performance Evaluation Task force which was established by the Corps’ Chief of Engineers to provide credible and objective scientific and engineering answers to fundamental questions about the performance of the hurricane protection and flood damage reduction system in the New Orleans metropolitan area. IPET included more than 150 nationally recognized experts from more than 50 federal, state and local government agencies; academic institutions and the private sector.

LaCPR: The Louisiana Coastal Protection and Restoration (LaCPR) study is a comprehensive hurricane protection analysis and design study directed by the Secretary of the Army, through the Chief of USACE, to develop and present a full range of flood control, coastal restoration, and hurricane protection measures for the Louisiana coastal area. USACE and the State of Louisiana have assembled a team of expert scientists and engineers to develop a decision framework that will be used by Congress and others to consider a vast array of information necessary to make informed decisions.

NFIP: National Flood Insurance Program was established by the U.S. Congress with the passage of the National Flood Insurance Act of 1968. The NFIP is a Federal program enabling property owners in participating communities to purchase insurance as a protection against flood losses in exchange for State and community floodplain management regulations that reduce future flood damages. Participation in the NFIP is based on an agreement between communities and the Federal Government. If a community adopts and enforces a floodplain management ordinance to reduce future flood risk to new construction in floodplains, the Federal Government will make flood insurance available within the community as a financial protection against flood losses. This insurance is designed to provide an insurance alternative to disaster assistance to reduce the escalating costs of repairing damage to buildings and their contents caused by floods.

NRC: National Research Council of the USA is the working arm of the United States National Academy of Sciences and the United States National Academy of Engineering, carrying out most of the studies done in their names. NRC provided an external peer review of IPET’s study.

Overtopping: When water flows over the top of a levee or structure

Performance: Capability of the system

Polder: Synonymous with sub-basin (Dutch term)

Reach: A segment or span of a linear structure (i.e., span of a levee)

Risk: The combination of the likelihood and the consequences of a specified hazard being realized. It is a measure of harm or loss associated with an action.

Risk Management: The systematic application of policies, practices, and resources to the assessment and control of risk affecting human health and safety and the environment (built and natural).

Risk and Reliability Model: Analyzes the performance of the system against the possible hazards to understand and quantify risk so that it can be managed.

Saffir-Simpson Scale: A 1-5 rating based on the hurricane's present intensity. This is used to give an estimate of the potential property damage and flooding expected along the coast from a hurricane landfall. Wind speed is the determining factor in the scale, as storm surge values are highly dependent on the slope of the continental shelf and the shape of the coastline, in the landfall region. Note that all winds are using the U.S. 1-minute average.

SELA: Southeast Louisiana Flood Control Project provides for engineering, design, and construction of projects for flood control and improvements to rainfall drainage systems in Jefferson, Orleans and St. Tammany Parishes.

Storm Types*: The probability of a storm occurring is typically communicated in one of two ways; as a percentage, or as a #-year storm. Here are some examples:

* NOTE: Hurricane Katrina was a 397-year storm, a storm that had a .252% chance of occurring in any given year.

Sub-basin: A normal natural drainage area in a city or parish