Laserfiche WebLink
<br /> <br /> <br />Level of protection-The greatest flood level against which a <br />protective measure is designed to be fully effective; often <br />expressed as a recurrence interval (e.g., 100-year level of <br />protection) or as an exceedance frequence (e.g., I-percent <br />chance of exceedance). <br /> <br />National Flood Insurance Program-The program under which <br />communities may be eligible for federally subsidized flood <br />insurance on the condition that the communities enact <br />satisfactory flood plain management regulations. <br /> <br />100-year frequency flood-A flood having an average frequency <br />of occurrence on the order of once in 100 years although the <br />flood may occur in any year. It is based on statistical <br />analyses of streamflow records available for the watershed <br />and analyses of rainfall and runoff characteristics in the <br />general region of the watershed. <br /> <br />Seepage-The passage of water or other fluid through a porous <br />medium, such as the passage of water through an earthen <br />embankment or masonry wall. <br /> <br />Standard Project Flood-The flood that may be expected from <br />the most severe combination of meteorological and <br />hydrological conditions that are considered reasonably <br />characteristic of the geographical area in which the <br />drainage basin is located, excluding extremely rare <br />combinations. Such floods, as used by the Corps of <br />Engineers, are intended as practicable expressions of the <br />degree of protection that should be sought in the design of <br />flood control works, the failure of which might be <br />disastrous. <br /> <br />Underseepage-Seepage along the bottom of a structure, <br />flood wall, or levee or through the layer of earth beneath it. <br /> <br />Uplift-The upward pressure of water, as on the base of a <br />structure. (See also the term "hydrostatic loads. ") <br /> <br />Velocity-The rate or speed that water flows, usually expressed <br />in feet per second. One foot per second is equivalent to <br />about 0.7 mile per hour. <br /> <br />13 <br />