Secondary and Cumulative Impacts Master Management Plan - 2014

502 / 634

Article 6: Riparian Buffers
Section 6.9. Mitigation
6.9.1. Applicability
Morrisville, NC April 2013
Unified Development Ordinance - Public Review Draft Page 6-17
Table
Use or Activity Exempt [1] Allowable [2]
Allowable
with
Mitigation [3]
and issuance of an Authorization Certificate in accordance with Section 6.5, Riparian Buffer Development Review.
[3] Uses and activities designated as ‖Allowable with Mitigation‖ are allowed only if no practical alternatives are available and on
approval and issuance of an Authorization Certificate with a mitigation strategy in accordance with Section 6.5, Riparian Buffer
Development Review, and
[4] Perpendicular crossings are those that intersect the surface water at an angle between 75 and 105 degrees.
[5] Overhead electric lines crossing Zone One shall comply with all of the following best management practices, unless the Board of
Adjustment finds no practical alternative exists to such compliance:
 A minimum zone of 10 feet wide immediately adjacent to the water body shall be managed such that only vegetation that poses
a hazard or has the potential to grow tall enough to interfere with the line is removed.
 Woody vegetation shall be cleared by hand. No land grubbing or grading is allowed.
 Vegetative root systems shall be left intact to maintain the integrity of the soil. Stumps shall remain where trees are cut.
 Riprap shall not be used unless it is necessary to stabilize a tower.
 No fertilizer shall be used other than a one-time application to re-establish vegetation.
 Construction activities shall minimize the removal of woody vegetation, the extent of the disturbed area, and the time in which
areas remain in a disturbed state.
 Active measures shall be taken after construction and during routine maintenance to ensure diffuse flow of stormwater through the
buffer.
 In wetlands, mats shall be utilized to minimize soil disturbance.
[6] Poles or other above-ground utility line infrastructure shall be installed within 10 feet of a water body unless the Board of
Adjustment finds no practical alternative exists to such location.
[7] Underground utility lines crossing Zone One shall comply with all of the following best management practices, unless the Board of
Adjustment finds no practical alternative exists to such compliance:
 Woody vegetation shall be cleared by hand. No land grubbing or grading is allowed.
 Vegetative root systems shall be left intact to maintain the integrity of the soil. Stumps shall remain, except in the trench where
trees are cut.
 Underground cables shall be installed by vibratory plow or trenching.
 The trench shall be backfilled with the excavated soil material immediately following cable installation.
 No fertilizer shall be used other than a one-time application to re-establish vegetation.
 Construction activities shall minimize the removal of woody vegetation, the extent of the disturbed area, and the time in which
areas remain in a disturbed state.
 Measures shall be taken on completion of construction and during routine maintenance to ensure diffuse flow of stormwater
through the buffer.
SECTION 6.9. MITIGATION514
6.9.1. Applicability515
This subsection applies where a Riparian Buffer Development Review application proposes a use or
activity listed as ―Allowable with Mitigation‖ in Table
or where mitigation is proposed or required as a condition of approval for a Riparian Buffer Variance
application. Any application for Riparian Buffer Development Review or a Riparian Buffer Variance that
proposes mitigation shall include a written mitigation proposal that calculates the required area of
514 NOTE: This carries forward the mitigation standards in Sec. 9.C of the current Riparian Buffer Ordinance. NCDQ has recently
proposed and held public hearings on consolidated riparian buffer mitigation standards, and is currently receiving comments on
the proposed standards. Those proposed standards expand a number of current provisions and allow additional options for
meeting the standards. They also expand the formula for calculating the area of mitigation to include multipliers relating to the
location of mitigation relative to that of the impacted area. This subsection is modified to incorporate those minor proposed
changes that merely further explain or address obvious gaps in the current standards. This subsection does not incorporate the
more substantive proposed changes, but will be revised later to do so if the proposed changes are adapted. The current provisions
are reorganized to a small extent to make them clearer.
515 This carries forward provisions in Sec. 9.C.1 of the current Riparian Buffer Ordinance except for the last provision, which makes
no sense since it pertains only to State-administered programs.