US Army Corps of Engineers
Sacramento District Website

Levee Safety Program

Levee systems are part of our nation’s landscape and provide important benefits to communities behind them. There are approximately 1,600 miles of levees in the Sacramento District’s Levee Safety Program spread out across California, Nevada, Utah, and Colorado. More than one million people live or work behind these levees, and over $165 billion worth of public and private property exists.

Levees reduce flood risk to people, businesses, critical infrastructure, and the environment, however it’s important to recognize they don’t eliminate flooding. Flood risk and levee condition are dynamic.  Levees change over time: banks erode, closures rust, animals burrow, and pumps wear out.  Ongoing vigilance is needed to reduce the risks associated with flooding. The Sacramento District works with non-Federal sponsors and stakeholders to manage and communicate flood risks to residents and businesses. Our partners play an important role in levee safety because we all must work together, sharing responsibility, to solve and manage flood risk challenges.

The Sacramento District routinely inspects and performs risk assessments on levees (and other flood risk management features) within its area of responsibility to monitor their overall condition, identify deficiencies, verify that needed maintenance is taking place, and provide information about the levee to communities who live and work behind them. Operation, maintenance, repair, rehabilitation and replacement activities are the responsibility of the non-Federal sponsor for all levee systems in the Sacramento District’s Levee Safety Program.

 FREQUENTLY ASKED QUESTIONS

Levee Inspections

The Sacramento District regularly inspects levees within its Levee Safety Program to monitor their overall condition, identify deficiencies, verify that needed maintenance is taking place, determine eligibility for federal rehabilitation assistance (in accordance with Public Law 84-99), and provide information about the levees on which the public relies.  Inspection information also contributes to risk assessments and informs levee accreditation decisions for the National Flood Insurance Program administered by the Federal Emergency Management Agency (FEMA).

Inspection ratings are based on the levee inspection checklist, which includes 125 specific items dealing with operation and maintenance of levee embankments, floodwalls, interior drainage, pump stations, and channels.

Ratings are assigned based on the following:

Levee Safety Risk Assessments

Approximately every ten years, USACE will perform a risk assessment on each levee within its portfolio. USACE uses risk assessments to prioritize life safety risks for its own levee safety activities, and also to provide a basis for communicating risk so levee sponsors and other stakeholders can make more informed decisions. Risk assessments place levees into risk categories from very high risk to low risk by evaluating three components of risk:

  1. Hazard: What possible loading events (flood, storm, earthquake, etc.) could occur? How likely will these events occur?
  2. Performance: How will the levee perform when subjected to these events?
  3. Consequences: What are the consequences if the levee doesn't perform well – in particular, what loss of life could occur?

Key Program Definitions

Levee - A man-made structure, usually an earthen embankment or concrete floodwall, designed and constructed in accordance with sound engineering practices to contain, control, or divert the flow of water so as to provide reasonable assurance of excluding temporary flooding from the leveed area. 

Levee Segment - A portion of a levee system that is operated and maintained by a single entity along a single body of water. 

Levee System - One or more levee segments and other features such as floodwalls and pump stations, which are interconnected and necessary to exclude flood waters from the associated leveed area. 

Leveed Area - The lands from which flood water is excluded by the levee system. 

Risk - Risk is a tool that is used to understand and communicate the probability (or likelihood) and consequence of uncertain future events. If there is no chance of an event occurring, then there is no risk. If there are no consequences resulting from an event occurring, then there is no risk. There could be two situations that seemingly have identical risk, but what is driving the risk for each of the two situations can be extremely different.

Hazard - Hazards are events that cause the potential for an adverse consequence. Typically, the hazards considered in levee safety are potential flooding sources and seismic hazards. Risk enables an understanding of the likelihood of possible hazards and how they may change over time.

Performance - Risk provides a framework for consistently evaluating the probability (or likelihood) of how the levee system is anticipated to function given possible hazards. This is done through considering a combination of past performance, existing conditions, maintenance, and how the existing levee compares to current engineering standards. How the levee is expected to perform may change over time based on the current understanding of industry best practices for levee design and operation despite unchanging levee conditions.

Consequence - Consequences are the effect or outcome resulting from the combination of the hazards and performance. In order to provide a complete picture of the risk and to facilitate more informed decisions, consequences are included in the risk discussion. Potential consequences can also be used to show the benefits provided by a levee system. Consequences may include estimates of potential impacts to life, property, environment, or navigation. All consequences should be considered to inform responsible and transparent decisions.