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<br />
<br />can be made easier if driveways, streets, and structures
<br />are located in the area of the site least likely to be
<br />flooded. Furthermore, in new developments, roads
<br />should approach buildings from the direction opposite
<br />the floodplain. This can help prevent the creation of
<br />unreachable islands containing individual homes or
<br />other structures. Erosion and runoff problems can be
<br />minimized if roads are designed in a way that does not
<br />disrupt natural drainage patterns.
<br />The Sacramento County, California, Interim
<br />Floodplain Development Guidelines (1993) contain
<br />several policies regarding access to newly developed
<br />properties in the flood plain. The policies are designed
<br />to ensure reasonable access to the properties during a
<br />storm, particularly by emergency vehicles, and to avoid
<br />creating islands during normal flooding. The guidelines
<br />recommend that, at a minimum, road access to the
<br />buildable area of ne\'\'!y created parcels be at or above
<br />the lO-year flood elevation. In addition, the number of
<br />waterc~urse crossings should be minimized by
<br />prohibiting the creation of lots that require an
<br />individual crossing. The State of Minnesota requires
<br />that road access to residential subdivisions be no 10v,Ter
<br />than one foot below the regulatory flood elevation.
<br />
<br />Minimizing Damage to Utilities and Roads
<br />Adequately protecting utilities from flood damage
<br />can minimize the amount of time homes and
<br />subdivisions cannot be occupied during and after a
<br />flood. NFIP minimum subdivision requirements with
<br />regard to utilities state:
<br />
<br />If a subdivision proposal or other proposed new
<br />development is in a flood-prone area, any such
<br />proposals shall be reviewed to assure that. . . (ii) all
<br />public utilities and facilities, such as se\\fer, gas,
<br />electrical, and \,\rater systems, are located and
<br />constructed to minimize or eliminate flood damage.
<br />(Sec. 60.3 (a)(4)(ii)).
<br />
<br />The goal, therefore, should be to first protect homes
<br />from flood damage and, second, to minimize
<br />disruptions in ,vater, sewer, and electrical service. The
<br />objective is to ensure that homes are immediately ready
<br />to be occupied after flood'rvaters recede, even if they
<br />had to be evacuated for a period of time during the
<br />flood. To accomplish this, all utility lines and
<br />mechanical equipment in individual homes should be
<br />kept above BFE. This will ensure that emergency
<br />officials will have access to equipment (especially
<br />control panels) during a flood if necessary. All
<br />equipment that must be placed below BFE should be
<br />fully \'\'aterproofed. Controls for systems located on
<br />lower floors and in basements may be installed
<br />separately to allow independent disconnection during
<br />flooding.
<br />This ;..JFIP requirement to minimize or eliminate
<br />flood damage potential to utilities essentially gives the
<br />local government the responsibility of establishing flood
<br />protection standards for public utilities. A minimization
<br />standard would state that the utility would repair and
<br />restore service to affected property o\vners within an
<br />established period of time (say, 24 to 48 hours)
<br />following a 1 percent annual chance of flood or less. An
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<br />elimination standard would state that components of
<br />the system must not be interrupted from service by a
<br />1 percent annual chance flood. This \""ould necessitate
<br />flood proofing or elevation.
<br />FEMA has not established specific standards for local
<br />governments to make a determination as to whether a
<br />subdi'vision is reasonably safe or whether utilities are
<br />positioned in a way that minimizes or eliminates the
<br />potential for damage. The agency does assume,
<br />however, that public utility companies, as a standard
<br />practice, will develop contingency plans to restore
<br />service to systems that may be damaged by flooding.
<br />Therefore, if a community decides to allO\,v installation
<br />of utility systems that do not meet the elimination
<br />standard, they must evaluate the utility company's
<br />ability to minimize flood damage and to restore and
<br />repair a system as quickly as possible in fhe event that
<br />components are damaged in a flood.
<br />FEMA has a list of factors for a local government to
<br />consider as part of an overall determination of the
<br />minimization standard.
<br />
<br />. Ability of the utility company, in terms of personnel,
<br />equipment, and supplies to repair and replace
<br />damaged components
<br />
<br />. Size of the service areas ,vithin and outside the 100-
<br />year floodplain
<br />
<br />. Estimate of the current and projected number of
<br />structures ,.vith electrical meters and transformers
<br />below BFE
<br />
<br />. Estimate of the projected number of structures
<br />vvithout pmver during a base flood event due to
<br />inundation of system components
<br />
<br />. Estimate of the length of service interruption
<br />
<br />. Utility companies' repair and replacement plan
<br />
<br />. History of the implementation of emergency
<br />procedures in prior floods
<br />
<br />. Anticipated gro,.vth of the service area that has
<br />potential for flood and is subject to the contingency
<br />plan to restore or repair service
<br />
<br />Within a site, roads should approach buildings in the
<br />direction away from the floodplain. This can help
<br />ensure that roads remain passable during a flood and
<br />that they stay free of debris being carried in flood
<br />,,,.raters. Roads and bridges that cross a flood way should
<br />be perpendicular to the \'\'atercourse. This limits the
<br />length of the bridges and minimizes the need to alter
<br />streams and riverbanks to accommodate structures.
<br />Thev should also be constructed in a ,"vav that a11O\,vs
<br />flood waters to move freely through or ~nder them. The
<br />slope of embankments on the sides of raised roads
<br />should be minimized and stabilized with terraces and
<br />ground cover.
<br />"Iany communities that are at risk of natural disasters
<br />have prepared evacuation plans or disaster
<br />preparedness plans. Such a plan should outline
<br />evacuation routes and procedures for subdivisions that
<br />may be subject to flooding. Streets that are designated
<br />as evacuation routes are generally those with adequate
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