NCG010000_NCG01 Fact Sheet_20110715

July 15, 2011
DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
FACT SHEET
GENERAL PERMIT
NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM
PERMIT TO DISCHARGE STORMWATER FROM
CONSTRUCTION ACTIVITIES
Permit No. NCGO10000
1. TYPES OF DISCHARGES COVERED
a. Activities Covered by this General Permit
Stormwater runoff discharged as point source(s) from construction activities including
clearing, grading, and excavation activities which will result in the disturbance of one or
more acres of total land area.
b. Types of Operations Covered
Point source conveyance of stormwater runoff from construction activities, including
clearing, grading, and excavation activities that result in the disturbance of one or
more acres of total land area and require a Sedimentation and Erosion Control plan.
C. Characteristics of Discharged Stormwater
Stormwater discharged will contain sediments eroded from the site of land disturbance
activity. Suspended sediment is the primary constituent in construction stormwater and is
commonly measured as total suspended solids (TSS) and/or turbidity:
• Total suspended solids (TSS) is a measure of the suspended material in water.
The measure of TSS in stormwater allows for an estimation of sediment
transport, which can have significant effects in downstream receiving waters.
Turbidity, expressed as Nephelometric Turbidity Units (NTU), is a measure of
the ability of light to penetrate the water. Turbidity is a function of the
suspended solids in water. Turbidity has been demonstrated to adversely
affect aquatic species, such as the ability of small macroinvertebrates to
survive or reproduce, as well as adversely affect fish populations directly and
indirectly [W.F. Henley et al., 2000].

NCG010000 Fact Sheet - NC DENR
July 1S, 2011
There is also the potential for fluids (fuels, lubricants, hydraulic fluids, coolants, etc.) from
construction equipment or machinery to contaminate stormwater during construction
activity. In addition, materials stored on the construction site such as chemicals,
explosives, etc., could enter the stormwater runoff discharge.
d. Geographic Area(s) Covered by this General Permit
Discharges covered by this General Permit are located at any place within the political
boundary of the State of North Carolina (discharges located on the Cherokee Indian Tribal
Reservation are subject to permitting by the U.S. Environmental Protection Agency (EPA)
and are not covered by this General Permit).
e. Receiving Waters
Receiving waters include all surface waters of North Carolina or municipal separate storm
sewer systems conveying stormwater to surface waters.
f. Why Have a General Permit?
A general permit for construction activities is an appropriate permitting approach because:
• A general permit is an efficient method to establish the essential regulatory
requirements that are appropriate for a broad range of construction activities;
• A general permit is the most efficient method to handle the large number of
construction stormwater permit applications;
• The application requirements for coverage under a general permit are far less
rigorous than individual permit application requirements and hence more cost
effective;
• A general permit is consistent with EPA's four -tier permitting strategy that aims to
use the flexibility provided by the Clean Water Act in designing a workable and
reasonable permitting system.
2. DISCHARGE CONTROLS AND LIMITATIONS*
* See item c. below for a summary of the differences in the conditions of the Final General
Permit from the previous permit conditions.
a. Description of Typical Stormwater Controls and Treatment Facilities
Erosion Controls are designed to prevent erosion by protecting soils. Sediment controls
are designed to remove sediment from runoff before the runoff is discharged from the
site. Major types of sediment and erosion control practices are:
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NCG010000 Fact Sheet - NC DENR
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Land Cover
Mulches
Straw
Hydro mulch
Blankets and other "rolled"
products
Vegetative Practices
Structural Practices
Earthen dike
Silt fence
Drainage swales
Check dams
Levelspreader
Temporary seeding
Permanent seeding
Sod stabilization
Vegetative buffer strips
Protection of existing trees and
vegetation
Pipe slope drain
Temporary storm drain diversion
Storm drain inlet protection
Rock outlet protection
Sediment Traps and Basins
b. Final General Permit Stormwater Pollution Prevention Requirements
Listed below are several pollution prevention requirements and conditions of the General
Permit that are critical to compliance.
• Construction activities disturbing one or more acres of land will need a local or state
sediment and erosion control plan and coverage under the NPDES General Permit
for stormwater point source discharges;
• Local or state sediment/erosion control plans must be approved before disturbance
occurs;
• Must implement the state or local plan (deviations are a violation of the permit);
• Copy of all plans retained by permittee;
• Deposition of sediment off site, or in a stream or wetland, are considered violations
of the permit;
• Visible deposition of sediment shall be reported to the DWQ within 24 hours of
inspection;
• Corrective action shall be taken immediately to control discharge of any sediments
off site or into waters of the state;
• A rain gauge shall be maintained on the site;
• A written record of the daily rainfall amounts shall be retained;
• At least once per week, each control measure shall be inspected to ensure that it is
operating correctly and records maintained;
• Control measure inspections should also be made within 24 hours of rain events
greater than 0.50 inches;
• The quality of all stormwater discharges shall be observed and recorded;
• Specific requirements are outlined for the handling of concrete materials
• Soil stabilization on any area of the site where land -disturbing activities have
temporarily or permanently ceased according to the schedule in Table 1 below:
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Ground Cover Requirements for
Slope Conditions
50' or greater 7 days 7 days 7 days 14 days
c
@1 7 days 7 days 14 days 14 days
m
CL
7 days 14 days 14 days 14 days
10' or less -
Steeper than Z.i Steep2e than 3;1 a;1— 4;1 Flatter than 4;1
Table 1- New Ground Cover Requirements for Construction Sites
C. Changes From the Existing General Permit
Below is a list of the most notable changes included in the Final General Permit:
• There are substantial changes to the ground cover requirements. Ground cover
would be required within seven (7) days of temporary or permanent stopping of
work for all perimeter dikes, swales, ditches, perimeter slopes, and all slopes
steeper than 3:1. On all other areas, ground cover would be required within 14 days
(except in special watersheds). See Table 1 above.
• Added protections for projects draining to all High Quality Waters.
• Improved language on requirements to install, implement and maintain BMPs.
• Added 50' setback requirement for stockpiles, and storage of land clearing,
demolition debris, construction and domestic waste, and hazardous or toxic waste
on construction sites.
• Added some definitions - "Control Measure" and "Stormwater Pollution Prevention
Plan" and clarifying language to other Sections. The terms "Temporary
Stabilization" and "Permanent Stabilization" are also now defined.
3. EXPANDED PERMIT REVIEW AND REVISION PROCEDURE
The Division of Water Quality (DWQ) determined early in the permit development process
that it needed a more robust mechanism to involve the various stakeholders than it had
traditionally used for this permit. Therefore, DWQ established a Construction General
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NCG010000 Fact Sheet - NC DENR July 1S, 2011
Permit Technical Advisory Group, or "CTAG," to work with DWQ staff in discussing various
options for revision. The CTAG was made up of 14 members representing regulatory,
environmental, and development interests. Either the entire group or a subgroup met 14
times since it was formed in July 2010. The meetings were also open to the public, and
many citizens attended. Notes from all meetings were documented and provided both to
the participants and to those on an extended mailing list. CTAG did not vote on the final
recommended draft permit, but the Group did discuss all significant issues prior to DWQ
staffs preparation of the draft. As expected, not all members would voice support for all
items in the proposed permit. However, DWQ was pleased with the support for the general
direction of the permit development. A public comment period was held and a public
meeting. Although many, helpful comments were received, the low volume of comments
(only three letters) were taken as an indication that most of the difficult issues had been
worked out during the year -long CTAG process.
4. MONITORING AND REPORTING REQUIREMENTS
Turbidity Monitoring and Limits
One of the most difficult parts of the permit review process was trying to develop a
program for permittee self -monitoring and the DWQ's enforcement of a turbidity effluent
limit in the federal Effluent Limitation Guidelines (ELG) for Construction and Development
(40 CFR § 450). The Technical Advisory Group (CTAG) working on this permit spent
several meetings discussing options for implementing a turbidity monitoring program.
Although the intent of the CTAG was to develop a viable monitoring and enforcement
program that could be implemented by August 2, 2011, there were major obstacles to
overcome.
a. There is no EPA -approved field measurement technique for turbidity. A method
needs to be developed. This issue does not just pose a problem for permittees; there
is a great need for an EPA -approved monitoring technique to assist the states in how
to monitor discharges and enforce on a daily average number. With no single -
sample maximum number recognized in the ELG, there remain unanswered
questions like, "how many samples must the DWQ enforcement staff collect in order
to get a daily average?" The problem of measuring turbidity has not been solved,
and DWQ sees no easy solution. In recognizing that the issues surrounding
monitoring protocol and measuring techniques had not been addressed on a
national level, DWQ staff concluded that these issues were not going to be addressed
soon on an individual state level either.
b. In addition to the issue of field measurement technique, the unavailability of the
final turbidity effluent number (EPA initiated a stay for the numeric turbidity limit
in 40 CFR § 450 until further notice) led staff to recommend a permit without
discharge monitoring requirements. Of course, North Carolina's in -stream water
quality standard for turbidity still applies and is being enforced by the Division
of Water Quality.
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Ground Cover Soil Stabilization Requirements
Although the Division recognizes the benefits of a turbidity effluent number, it strongly
believes that enforcing on ground cover requirement is a much more effective way to
achieve reduced sediment loading to the state's waters. Therefore, the permit contains
additional soil stabilization best management practices to accomplish the intent to reduce
turbidity in, and the potential for sedimentation from, construction site discharges. The
permit conditions specify that temporary or permanent ground cover should be applied on
slopes greater than 3:1 within seven (7) days of cessation of land disturbance in any area of
a site. We believe that this requirement alone will substantially reduce the discharge of
sediment to North Carolina streams and other waterbodies.
5. COMPLIANCE SCHEDULE
The permittee shall comply with inspection, monitoring, and controls specified for
stormwater discharges once disturbance has begun on the site and until completion of
construction or development and the establishment of a permanent ground cover.
During construction and until the completion of construction or development and the
establishment of permanent ground cover, the permittee shall provide the operation and
maintenance necessary to operate the stormwater control measures and all erosion and
sedimentation control measures at optimum efficiency.
6. SPECIAL CONDITIONS WHICH CAN BE APPLIED
In certain watersheds or with certain projects, additional requirements may be applied.
Listed below are examples of situations where special conditions may be applied.
The general permit contains language that indicates that where a project is
proposed and the discharge could adversely affect a Federally Listed Threatened
and Endangered Species, the Division may require special "Design Standards in
Sensitive Watersheds" (15A NCAC 04B .0124). These measures are applicable
where the listed species has the potential to be impacted by construction site runoff.
• Land disturbing activities in designated "High Quality Waters" will require the
additional measures specified in "Design Standards in Sensitive Watersheds."
• The revised permit makes it clear that the State can mandate additional BMP
requirements for activities in sediment -impaired 303(d) streams.
The Division of Land Quality of DENR has authority in 15A NCAC .04B .0115 to apply
"Additional Measures" when it is determined that significant erosion and
sedimentation continues despite the installation of standard protective practices.
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The Division of Water Quality retains authority to require an individual permit any
time that an activity causes, or has a potential to cause, a violation of a water quality
standard.
7. BASIS FOR CONTROLS AND LIMITATIONS
The Federal Clean Water Act (FCWA, 1972, and later modifications, 1977, 1981, and 1987)
established water quality goals for the navigable (surface) waters of the United States. One
of the mechanisms for achieving the goals of the Clean Water Act is the National Pollutant
Discharge Elimination System permit program (NPDES permits), which is administered by
the Environmental Protection Agency (EPA). The EPA has delegated responsibility to
administer the NPDES permit program to the State of North Carolina. There is an
Agreement between the EPA and the State setting forth the authorities and specifications
for delegation to North Carolina.
Non -numeric Effluent Limitations that Apply to Construction Sites
The federal Construction and Development Point Source Rule (40 CFR § 450, "C&D rule")
that became effective February 1, 2010 includes non -numeric effluent limitations. The
Final permit addresses each of these requirements.
Erosion and Sediment Controls
Construction activities may result in severe localized impacts on water quality due to high
loads of pollutants, primarily sediment, associated with the erosion of disturbed land
surfaces. Over a short period of time, construction sites can contribute more sediment to
streams than was deposited previously over several decades. These concerns are
addressed by the existing Sedimentation Control Program administered by the North
Carolina Division of Land Resources, Department of Environment and Natural Resources
under authority of the Sedimentation Pollution Control Act of 1973 as amended. Therefore,
compliance with the construction stormwater general permit relies substantially and
specifically on compliance with an approved Erosion and Sediment Control Plan.
The Sedimentation Control Program requires persons proposing to disturb more than an
acre of land surface to submit an erosion and sedimentation control plan at least 30 days
prior to beginning of the land disturbing activity. These plans are submitted to the regional
engineer for Land Quality located in one of the seven Department regional offices or to a
delegated local program. The Land Resources Division developed the Erosion and
Sediment Control Planning and Design Manual to assist applicants in the preparation of
such plans. Additionally, each plan is compared to a checklist of requirements to assure
completeness and consistency in the review and approval process.
The Division of Land Resources also delegated their review and approval program to
approximately 50 local governments in North Carolina. In addition to plan review and
approval, the Land Quality Section inspects facilities for compliance, investigates
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complaints, provides technical assistance, and conducts routine overview of the delegated
local programs.
The specific requirements for all erosion and sediment control plans are contained in Title
15A North Carolina Administrative Code Chapter 4 (15A NCAC 4). These rules address the
requirements for submission of approvable erosion and sedimentation control plans, the
approval process, mandatory standards for land disturbance activities, design and
performance standards, access and haul roads, maintenance, inspections and
investigations, design standards in sensitive watersheds, and buffer zone requirements in
addition to other provisions. These procedures are administered and enforced in such a
manner as to provide protection of the receiving waters from pollution caused by erosion
from the land disturbance activity.
Soil Stabilization
The permit requires that soil stabilization with ground cover be achieved within 7-14 days,
depending on factors such as watershed location, slope grade, and slope length (refer to
Table 1 in Section 2 b. of this Fact Sheet). In addition, the permit outlines specific
parameters for what is considered "temporary" and "permanent" soil stabilization (See
"SECTION VIII. - DEFINITIONS").
Analysis of precipitation data across North Carolina (13 weather stations) during a 12-year
period demonstrated that on average, the probability of a 0.5" rainfall in one day is just
below 10 percent. While rain events are not distributed evenly through any given time
period and distribution is seasonally- and geographically -dependent and highly variable, the
long term average suggests that overall the state receives a half -inch rain event about every
11 days. A similar analysis suggests that a quarter -inch of precipitation falls in a 24-hour
period, on average, at least once every 4-7 days (depending on month and location). The
permit conditions to require ground cover must be established on steeper -slopes of
disturbed areas within 7 days will reduce the chances of significant rainfall
occurring before temporary or permanent stabilization is achieved.
Dewatering Discharges
The federal C&D rule prohibits discharges from dewatering of trenches and excavations
unless managed by appropriate controls. North Carolina Administrative Code (NCAC)
Section 15A: 02H .0106 (f) (7) permits such discharges by rule, provided that no water
quality standards are contravened or expected to be contravened.
Pollution Prevention Measures
The permit outlines pollution prevention measures in Section II.A.
Prohibited Discharges
Wastewater discharges (e.g., concrete washout, paint, oils, etc.) are not authorized by this
the permit. Dumping of liquid building material wastes in storm drains is prohibited, and
such wastes must be disposed of as required by state Statutes. Fuels, lubricants, coolants,
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NCG010000 Fact Sheet - NC DENR July 1S, 2011
and hydraulic fluids, or any other petroleum products are prohibited from being
discharged onto the ground or into surface waters.
Surface Outlets and Chemical Treatment
The permit requires sediment basins and impoundments to withdraw water from the
surface, with specific exemptions allowed for certain small on -site sediment traps.
Discharges must be directed from stormwater controls to vegetated areas unless infeasible.
The permit also proposes requirements for chemical flocculants, including limiting use to
those approved by DWQ.
8. REQUESTED VARIANCES OR ALTERNATIVES TO REQUIRED STANDARDS
There are no requested variances or alternatives to required standards.
9. THE ADMINISTRATIVE RECORD
The administrative record, including application, draft permits, fact sheet, public notice,
comments received, and additional information is available by writing to:
Stormwater Permitting Unit
Division of Water Quality
1617 Mail Service Center
Raleigh, North Carolina 27699-1617
The above documents are available for review and copying at:
Archdale Building
9th Floor
Surface Water Protection Section
Stormwater Permitting Unit
512 N. Salisbury Street
Raleigh, North Carolina
between the hours of 8:00 AM and 5:00 PM Monday through Friday. Copies will be
provided at a charge of 10 cents per page.
10. STATE CONTACT
Additional information about the permit may be obtained at the above address between
the hours of 8:00 AM and 5:00 PM Monday through Friday by contacting: Boyd DeVane at
[phone] or at boyd.devaneOncdenr.gov
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11. PERMIT ISSUANCE
Draft Permit to Public Notice - Notice published May 13, 2011
Closing date for comments - June 16, 2011
Public meeting held June 7, 2011
Permit Reissuance Effective Date - Scheduled for August 2, 2011
12. REFERENCES
Henley, W.F., 'M.A. Patterson,' R.J. Neves, and A. Dennis Lemly. Effects of Sedimentation and
Turbidity on Lotic Food Webs: A Concise Review for Natural Resource Managers.
Reviews in Fisheries Science, 8(2): 125-139 (2000).
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