(a) Curb and gutter streets
shall be required in all subdivisions having a minimum lot size of twenty-eight thousand
(28,000) square feet or less and in all subdivisions developed under the cluster
subdivision provisions of the zoning ordinance, regardless of lot size provided, however,
that the agent may waive or modify this requirement for infill lots created along an
existing street which has been developed without curb and gutter.
(b) Where the minimum lot size exceeds twenty-eight thousand
(28,000) square feet, curb and gutter streets shall be required in any subdivision where
the longitudinal slope (flowline slope) of any roadside ditch is less than one percent
(1%) and the maximum depth is three feet (3'). The depth of ditches shall be measured from
the invert elevation to the adjacent existing or finished grade, whichever shall yield the
greatest depth. However, the agent may permit this ditch depth to be exceeded where the
natural topography is so severe, exceptional, or extraordinary as to make other options
impractical or infeasible based on sound engineering practice and principles. Any request
for such consideration shall be made in writing and be accompanied by supporting
information to substantiate the request for the modification to the ditch depth
requirement.
(c) The subdivider of any subdivision exempted from the
requirements for curb and gutter established above shall provide a subsurface soils report
certified by a geotechnical engineer. Said report shall indicate and describe the various
soil strata encountered, specify the soil types based on the unified soil classification
system, indicate the elevation of the seasonal high water table, and indicate the presence
of perched water table conditions. Such report shall further indicate the probability that
the proposed roadside ditch system will intercept flowing groundwater or springs, or will
contain water as the result of the seasonal high water table or tidal flows. If either of
these situations is found to have a high probability of occurrence, curb and gutter shall
be required.
(d) If curb and gutter is required for any portion of a
subdivision, it shall be required for the entire subdivision.
(e) Where curb and gutter is required, the minimum longitudinal
slope shall be three-tenths of one percent (0.3%).