NCG010000_Consultant Group Comments_20231229

2024 North Carolina Department of Environmental Quality General Permit No. NCGO10000 to
Discharge Stormwater Under the National Pollutant Discharge Elimination System (NCG01)
NCG01
Current Permit Language
Input for Consideration
Part.Section
Part 1.1
1. Develop an E&SC Plan that adheres to the SWPPP
Request clarification in either Part I or Part II of NCG01 for 'lots -only
requirements of this permit, the SPCA, and 15A
standard plans' required minimum standards.
NCAC 04B.0101 -.0132.
Part II.A.1-8
6. Calculations
1. Due to the extensive length of the calculation documentation
■ Calculations for peak discharges of runoff from each outlet at
for erosion control plans, we ask that NCDEM LR consider an
pre -development, during construction and at completion.
alternative method for permittees to document that the
Provide all supporting data for the computation methods used
required calculations have been completed.
(rainfall data for required storm events, time of
concentration/storm duration, and runoff coefficients)
a. Alternative methods could include:
■ Design calculations for culverts and storm sewers (include
i. Allowing permittees to reference the hydrology
headwater, tailwater and outlet velocities)
study in the SWPPP and make it available upon
■ Discharge and velocity calculations for open channel and ditch
request; or
flows (easement & rights -of -way)
■ Design calculations for cross sections and method of stabilization
ii. An additional supplemental plan sheet be provided
for existing and planned channels (include temporary linings).
by NCDEMLR similar to the existing "Materials
Include appropriate permissible velocity and shear stress.
Handling" and "Required Timeframes for
■ Design calculations and construction details for energy
Temporary Stabilization" sample plan sheets that
dissipaters below culvert and storm sewer outlets (include
fulfill Sections E(2) and F of NCG01, that is set up as
stone/material specs & apron dimensions). Avoid discharges on
fill slopes.
a "fill in the blank" by designers where the specific
• Design calculations and dimensions for sediment traps and
information that NCDEMLR would like be provided
basins
could be added in a consistent format, with the
• Total and disturbed drainage areas for silt fencing and other
remainder of calculations available upon request.
sediment controls
2. Request for clarification, guidance, or examples for compliance
with the final calculation checklist item 'total and disturbed
drainage areas for silt fencing and other sediment controls.'
7. Vegetative Stabilization
Request for clarification on this design item, and/or allowance of a
■ Area and acreage to be stabilized with vegetation
percentage calculation instead of a specific acreage/area
calculation.

NCG01
Part.Section
Current Permit Language
Input for Consideration
Part II.B.1
"1. The approved E&SC plan as well as any approved
Request for expansion of electronically -available (digital) records to
and 2
deviation should be kept up-to-date throughout the
include all SWPPP documentation for the project including, but not
coverage under this permit. The items listed in Table 5
limited to, the E&SC plan and Table 5 items.
pertaining to the E&SC plan shall be kept on site and
available for inspection at all times during normal
business hours.
2.(b)Records of inspections made during the previous
twelve months. .....Use of electronically -available records
in lieu of the required paper copies will be allowed if
shown to provide equal access and utility as the hard -
copy records."
Part II.G.1
"Modifications to the approved E&SC plan that
Request for clarification that would allow for more consistency at
require changes to the E&SC measure designs, the
the regional office and local program level for specific triggers for
drainage areas, or the disturbed areas draining to
formal plan revision submittal vs what the Divisions view as 'minor
E&SC measures shall be approved by the E&SC
adjustments,' specifically in regard to the use of alternative BMPs
plan authority. Deviations from the approved E&SC
that achieve the same functionality as the original design (such as
plan, or approved revised E&SC plan, shall
different types of inlet protection).
constitute a violation of this permit unless the
deviation is to correct an emergency situation where
sediment is being discharged off the site. The E&SC
plan authority may allow deviations from the E&SC
plan on a case -by -case basis if the deviations are
minor adjustments to address minor deficiencies. A
minor adjustment shall be the addition ofE&SC
measures (e.g., silt fence, inlet protection, check
dams, rolled erosion control practices, etc), or the
relocation ofE&SC measures that would improve
the overall stormwater management and sediment
control onsite. Minor adjustments shall be noted on
the approved E&SC plan and maintained at the job
site. "

NCG01
Current Permit Language
Input for Consideration
Part.Section
Part II.G.2
"2. The permittee shall install and maintain all
Request for clarification on the required timeframe for completion
and 3
temporary and permanent E&SC measures as required
of maintenance and repair needs identified during inspections of
by this permit and the approved E&SC plan.
BMPs.
3. If self -inspections required by this permit..... these
actions shall be performed as soon as possible
considering adverse weather and site conditions."
Part III.A
Self -inspections 'at least once per 7 calendar days and
Request for consideration of alignment with the federal
within 24 hours of a rain event greater than or equal to
Construction General Permit regarding inspection frequency:
1.0 inch in 24 hours'
1. U.S. Environmental Protection Agency (EPA) CGP — Section 4.2.1
and 4.2.2:
"At least once every seven (7) calendar days; or
Once every 14 calendar days and within 24 hours of the
occurrence of:
a. A storm event that produces 0.25 inches or more of rain
within a 24-hour period.
b. A discharge caused by snowmelt from a storm event that
produces 3.25 inches or more of snow within a 24-hour
period."
Request for clarification of expectations of timing of rain event
inspections for storm events that occur over multiple days, and the
rain event threshold is met within one or more 24 hour periods.
Part III.A
"...The permittee may use another rain -monitoring device
Consider revising/clarifying expectations of the type of rain
approved by the Division."
monitoring device or digital platform that is allowable.
Example alternative language from the federal CGP:
"For rain, you must either keep a properly maintained rain gauge on
your site, or obtain the storm event information from a weather
station that is representative of your location."

NCG01
Current Permit Language
Input for Consideration
Part.Section
It is also recommended that consideration be given to a defined
allowable distance from the site a weather station could be located
and be considered 'representative', as well as requiring that the
weather station ID be included on the NPDES report.
Part III.C.2
"Within 24 hours, an oral or electronic notification.
Request that this be reworded to clarify the responsibility of the
Within 7 calendar days, a report that contains a
permittee to provide a report describing the sediment impact and
description of the sediment and actions taken to address
actions taken in scenarios when there is no Division response to the
the cause of the deposition. Division staff may waive the
permittee following the initial self -report notification.
requirement for a written report on a case -by -case
basis."
Example potential revision:
"Within 24 hours, an oral or electronic notification. Within 7
calendar days, a report that contains a description of the sediment
and actions taken to address the cause of the deposition, if
requested by the Division following the initial self -report
notification."
Part III
"A person is a duly authorized representative only if...
Request that an alternative method is provided for this
■ The written authorization is submitted to the
documentation of delegation authority such as:
Director [40 CFR 122.22]."
■ The signed and dated written authorization is included in the
SWPPP. A copy shall be provided to the department and VSMP
authority, if requested.
Part V
Definitions
Request definition of 'outlets'
■ Request addition of street -washing waters to the Allowable
Non-Stormwater Discharges list that is included within the
definitions.
Example language from the Maryland CGP is included below:
"Pavement wash waters, provided spills or leaks of toxic or
hazardous substances have not occurred (unless all spill
material has been removed) and where soaps, solvents, and

NCG01
Part.Section
Current Permit Language
Input for Consideration
detergents are not used. You are prohibited from directing
pavement wash waters directly into any Waters of this State,
storm drain inlet, or stormwater conveyance, unless the
conveyance is connected to a sediment basin, sediment trap, or
similarly effective control."
■ Request clarification of Stormwater Discharge Outfall definition
in relation to silt fence outlets
Additional Question/Comment
1. Will the NCDEMLR supplemental plan sheets be open for public comment during the draft 2024 NCG01 period?
a) Is there an opportunity for the addition of a residential lot -specific tracking pad/stabilized construction entrance standard detail for
homes under construction that are less than 50' (the required minimum length of the current construction entrance) from a paved
road? An example description would be a 20' x 20' pad with a geotextile liner and a minimum 6" depth of 1" — 2" coarse aggregate
that could be added to the 'Materials Handling' plan sheet.