Nebraska Administrative Code › Topic - NATURAL RESOURCES, DEPARTMENT OF › Title 455 - NEBRASKA DEPARTMENT OF NATURAL RESOURCES - FLOODPLAIN MANAGEMENT › Chapter 1 - MINIMUM STANDARDS FOR FLOODPLAIN MANAGEMENT PROGRAMS › Section 455-1-004 - Minimum Standards Governing Location of Obstructions and Substantial Improvements in the Floodplains for the Base Flood

Current through June 17, 2024
The following minimum standards shall apply when an
				  obstruction is to be located or substantially improved within the floodplain of
				  a base flood. In the event of a conflict between the following minimum
				  standards and those in Section 005, the minimum standards in Section 005 shall
				  govern.
004.01 No new construction,
				substantial improvements, or other obstruction (including fill) shall be
				permitted unless it is demonstrated that the cumulative effect of the proposed
				new construction, when combined with all other existing and anticipated new
				construction or substantial improvement, will not increase the water surface
				elevation of the base flood more than one foot at any location.
004.02 To the extent otherwise permitted by
				the minimum standards in this Chapter, all new obstructions and substantial
				improvements shall (i) be designed (or modified) and adequately anchored to
				prevent flotation, collapse, or lateral movement of the obstruction, (ii) be
				constructed with materials and utility equipment resistant to flood damage,
				(iii) be constructed by methods and practices that minimize flood and flood
				related damages, and (iv) be constructed with electrical, heating, ventilation,
				plumbing, and air conditioning equipment and other service facilities that are
				designed and/or located so as to prevent water from entering or accumulating
				within the components during conditions of flooding.
004.03 All public utilities and facilities,
				such as sewer, gas, electrical, and water systems shall be located and
				constructed to minimize or eliminate flood damage to such utilities and
				facilities.
004.04 New and
				replacement water systems shall be designed to minimize or eliminate
				infiltration of flood waters into the system.
004.05 New and replacement sanitary sewage
				systems shall be designed to minimize or eliminate infiltration of flood waters
				into the system and discharges from the system into flood waters.
004.06 On-site waste disposal systems shall
				be designed to avoid impairment to them or contamination from them during
				flooding.
004.07 All new
				construction and substantial improvements of residential structures shall have
				the lowest floor (including basement) elevated to or above one foot above the
				base flood level.
004.08 All new
				construction and substantial improvements of non-residential structures shall
				(i) have the lowest floor (including basement) elevated to or above one foot
				above the base flood level or, (ii) together with attendant utility and
				sanitary facilities be designed so that below the level one foot above the base
				flood level the structure is watertight with walls substantially impermeable to
				the passage of water and with structural components having the capability of
				resisting hydrostatic and hydrodynamic loads and effects of buoyancy.
				Floodproofing measures shall be consistent with the flooding characteristics of
				the drainway or watercourse. A registered professional engineer or architect
				shall certify that the floodproofing methods to be utilized are adequate to
				withstand the flood depths, pressures, velocities, impact and uplift forces,
				sewage backups and other factors associated with the base flood.
004.09 Appurtenant structures used
				exclusively for storage of motor vehicles, and storage of other items readily
				removable in the event of a flood warning may have their lowest floor below one
				foot above the base flood elevation provided the structure is capable of
				withstanding hydrostatic and hydrodynamic forces caused by the base flood and
				provided that no utilities are installed in the structure except elevated or
				flood proofed electrical fixtures. If the structure is converted to another
				use, it must be brought into full compliance with the minimum standards
				governing such use.
004.10 For all
				new construction and substantial improvements, fully enclosed areas below the
				lowest floor that are usable solely for parking of vehicles, building access or
				storage in an area other than a basement and which are subject to flooding
				shall be designed to automatically equalize hydrostatic flood forces on
				exterior walls by allowing for the entry and exit of floodwaters. Designs for
				meeting this requirement must either be certified by a registered professional
				engineer or architect or meet or exceed the following minimum criteria: A
				minimum of two openings having a total net area of not less than one square
				inch for every square foot of enclosed area subject to flooding shall be
				provided. The bottom of all openings shall not be higher than one foot above
				grade. Openings may be equipped with screens, louvers, valves, or other
				coverings or devices provided that they permit the automatic entry and exit of
				floodwaters.
004.11 All
				manufactured homes to be placed or substantially improved on sites:
(i) outside of a manufactured home park or
				subdivision (ii) in a new manufactured home park or subdivision;
(ii) in a new manufactured home park or
				subdivision;
(iii) in an expansion
				to an existing manufactured home park or subdivision; or
(iv) in an existing manufactured home park or
				subdivision on which a manufactured home has incurred "substantial damage" as
				the result of a flood, shall be elevated on a permanent foundation such that
				the lowest floor of the manufactured home is at or above one foot above the
				base flood elevation, and shall be securely anchored to an adequately anchored
				foundation system to resist flotation, collapse, and lateral
				movement.