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<br />LocR! Dikes <br /> <br />Dikes have been used to protect individual structures or <br />small subdivisions, but can also be used to direct flocd <br />wate~s into streets or ohannels for safe oonveyance down- <br />fan. In a developed area, local dikes should be coordinated <br />with street layout and orientation. Use of dikes by <br />individual homeowners without such coordinRtion could result <br />in severe damages to adjacent structures. The design of <br />dikes varies widely, from simple masonry walls with no <br />structural reinforcing to massive earthen berms. Armoring <br />of dikes has been neglected on many fans. <br /> <br />street Orientation <br /> <br />streets in developed areas can be aligned along the maximum <br />slop~ to ~rovide flow carrying capacity. When combined with <br />local dikez and ~rop structures between homes. streets can <br />carryall of the flood flow through a subdivision. figure <br />6.1 shows one way these tools might be used. Such use <br />reqUires heavy armoring of street sides and large flow <br />depths; conditions which require depression of the streets <br />and special treatment of side streets and driveway <br />entrances. Transitions between subdivisions or between <br />streets and open space must be smooth to avoid excessive <br />scour or sediment deposition. <br /> <br />Elevation ~ Structures <br /> <br />Piles or fill may be used to elevate structures above the <br />base flood elevation and effectively remove them from the <br />flood hazards. Elevation on piles allows flow under the <br />building and minimizes obstructions in the flow path, while <br />elevation on fill substantially obstructs flow. A <br />subdivision built on fill requires an alternative flow <br />conveyance system such as armored streets. Elevation on <br /> <br />67 <br /> <br /> <br />