Within any floodway area, no encroachments, including fill,
new construction, substantial improvements, or other development shall
be permitted unless it has been demonstrated through hydrologic and
hydraulic analysis performed in accordance with standard engineering
practice that the proposed encroachment will not result in any increase
in flood levels within the community during the occurrence of the
base flood discharge. Hydrologic and hydraulic analyses shall be undertaken
only by professional engineers or others of demonstrated qualifications,
who shall certify that the technical methods used correctly reflect
currently accepted technical concepts. Studies, analyses, computations,
etc., shall be submitted in sufficient detail to allow a thorough
review by the Floodplain Administrator. However, in the cases of the
replacement or repair of damaged bridges and/or drain pipes, the standard
shall be that such replacement or repair of said bridges and/or drain
pipes do not worsen the existing flood levels during the base flood
discharge that existed prior to said replacement or repair. Such conclusion
that the replacement or repair of bridge and/or drain pipes does not
worsen the preexisting flood levels must be supported by the opinion
of a professional engineer. Additionally, any structure such as, but
not limited to, drain pipes, box culverts, and bridges etc., shall
be greater than or equal to cross-sectional area of the drainage channel
itself.