(1) Levees in the United States(a) A levee is a man-made earth structure constructed along a river or shoreline.(i) They are designed to control the flow of water during periods of floods or tidal storms. (ii) The presence of a levee theoretically protects adjacent lands from flooding. (b) All 50 states in the nation use levees to some extent. (i) Twenty-two percent of the 3,147 counties in the United States contain levees.(ii) They are most commonly found in states with long coastlines and/or large rivers.(2) Levee design(a) The location of a levee requires the analysis of both existing conditions and future plans for an area.(i ) It is necessary to decide whether the embankment will be located on river frontage or on private land and how far from the river the embankment will be located. (ii) The levee should provide adequate stream area to accommodate the design flood, without restricting flow so as to worsen flood impacts. (b) Location and associated costs usually determine the type of levee chosen. (i) The conventional earth embankment is by far the most common. (ii) Complete or partial retaining walls can be constructed when space is limited. (iii) Concrete retaining walls (flood walls) are a viable alternative in urban areas where available ground space is limited. (iv) A roadway may be scaled upward to create an embankment, if no other suitable alternative location exists. (c) Access requirements for a levee shall be considered during the design phase of a flood control project. (i) If there is a demand for public access, the design must take this into account. (ii) At present at a minimum, the embankment crest must be wide enough to accommodate a vehicle for maintenance purposes, including signage and on/off ramps. (iii) Access location...... middle of paper...... education.(5) Community awareness(a) Current regulations communicate the wrong messages to community members.(i) No measures necessary protection to build on land that will not be inundated by the 100-year flood.(ii) It is believed that flood protection is not necessary in communities protected by levees: there is no financial protection against levee failure. (b) The universal requirement of 100 years of flood protection may not be satisfactory. (i) Construction of new buildings should protect beyond this standard. (ii) Embankment heights constructed to protect densely populated areas should certainly provide additional protection. (c) A cost-benefit analysis of levee failures and alternatives should be conducted; benefits to reduce the likelihood of failure should be included. (d) A levee-educated public will be more likely to follow evacuation orders during periods of extreme flooding.