20140957 Ver 2_DWR Cumulative Impact Policy_20040410

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MEMO
April 10, 2004
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
TO: Coleen Sullins
FROM: John Dor
RE: Final vers6of DW ulative Impact Policy
Alan W. Klimek, P. E. Director
Division of Water Quality
Coleen H. Sullins, Deputy Director
Division of Water Quahty
Please see the attached final version (Version 2.1, dated April 10, 2004) of the
Cumulative Impact Policy for the 401 and Isolated Wetland Permitting Programs. The policy
was put out to public notice on October 3, 2002. We received comments from DOT, Charlotte -
Mecklenburg Stormwater Services, the NC Wildlife Resources Commission, the Home Builders
Association, and the US Environmental Protection Agency, I believe that this policy addresses
the questions raised by these comments. The policy has also benefited from our work over the
past year and one-half with DOT and various local governments.
Please advise as to the next step in getting final approval for this policy. I can be
reached at 733-9646. Thankx
Cc: Qb5hn Hennessy, Transportation Permitting
Dennis Ramsey
N. C. Division of Water Quality 1617 Mail Service Center Raleigh, North Carolina 27699-1617 [phone]
AM
NERMOM
Customer Service
1-877-623-6748

Cumulative impacts and the 401 Water Quality Certification and
Isolated Wetland Permit Programs
Division of Water Quality Internal Policy
NC Division of Water Quality
April 10, 2004
Version 2.1
Background
Existing rules for the 401 Water Quality Certification Program (15A NCAC 2H .0506(b)(4) and
(c)(4)) as well as those for the Isolated Wetland Permit Program (1 5A NCAC 2H .1300) require that DWQ
determine that a project "does not result in cumulative impacts, based upon past or reasonably
anticipated future impacts, that cause or will cause a Violation of downstream water quality standards."
This internal policy is meant to give direction to DWQ Central and Regional Office staff as well as the
regulated public on how to implement this rule. Cumulative impact is defined as those "environmental
impacts resulting from incremental effects of an activity when added to other past, present, and
reasonably foreseeable future activities regardless of what entities undertake such other actions" (taken
from 15A NCAC 1A which implement the State Environmental Policy Act) for the Department of
Environment and Natural Resources.
It is important to note that the 401 Certification rules require an examination of cumulative impacts
in terms of their impact on downstream water quality standardi and their associated designated uses.
This is a relatively narrow provision that requires DWQ staff to focus on downstream standards (narrative
and numeric) rather than (for instance) the effect of the development on wildlife habitat. Therefore, only if
that impact will cause a Violation of downstream water quality standards is the project of concern in the
context of cumulative impact for DWQ's wetland permitting programs. However, water quality standards
form the basis of all water quality regulation and permitting programs. This rule (although narrow in its
scope since- it focuses on downstream water quality) provides an essential tool for DWQ to use to
manage cumulative impact. Water quality impairment is usually tied to stormwater runoff that can
increase with road construction and urban development. This policy is intended to address this
regulatory requirement.
Polic
1. DOT (and other public transportation) projects
The major types of DOT projects and their need for different levels of cumulative analysis are
outlined below. The three types of cumulative impact analysis with respect to this policy are 1)
Generic description, 2) Qualitative analysis, and 3) Quantitative analysis.
A. Generic description of water quality impacts: Small-scale wideninq proiects, bridg
replacements proffiects and intersection improvement pro*ects — These projects which
include categorical exclusions (23 C.F.R. § 771.117) and minimum criteria (19A NCAC 2F
.0102) normally have a low potential for cumulative impact since little (if any) new
impervious surface is added and the projects are usually in already developed locales.
DWQ believes that a generic description can be developed which addresses the
cumulative impacts of the majority of these projects in the context of the 401 Certification
and isolated wetland rules. However, if DWQ staff determines that any of these projects
may have growth -stimulating effects and downstream impacts, then either a qualitative
cumulative impact analysis (see B below) or (more rarely) a quantitative analysis (see C

below) should be required of the applicant. These projects which will require a more
complex analysis often coincide with projects identified by the Pre-screening process of
the Department of Transportation.
B. Qualitative Analysis of water quality impacts: Proiects such as widening with new
locations: Most of these projects have a low potential for cumulative impacts since these
locations tend to be near existing roads and already developed areas. Therefore, a
narrative cumulative impact analysis prepared using the methodology outlined in the
DOTIDENR NEPA/SEPA document (Guidance for Assessing Indirect and Cumulative
Impacts of Transoortation Proiects in North Carolina. Volumes I and 11. 2001, State of
North Carolina Department of Transportation and Environmental and Natural Resources
prepared by The Louis Berger Group, Inc., Cary, N.C. or their updates) should suffice for
the 401 Certification and Isolated Wetland permitting programs.' If DWQ technical staff
determines that any of these projects will have drowth-stimulating effects and downstream
impacts, then a quantitative analysis should be required of the applicant (see below).
C. Quantitative (i.e., Detailed) Analysis of water auality impacts: Pro*ects such as roads
on new location: Many of these projects may have growth -stimulating effects (i.e., urban
growth beyond that expected without the project) since new growth has the potential to
occur on otherwise undeveloped property adjacent to the new road alignment. Therefore,
these projects may result in cumulative impacts to water quality. The overall process as
outlined below will be used to deal with new location projects or for any other project that
will have growth -stimulating effects, including projects that would otherwise be categorized
as "Generic Description" or "Qualitative Analysis" projects.
1 . Seguential questions to address for quantitative analyses:
a. Is arowth likely to be Induced by the prooect?-This may be indicated by
projected land use changes or by the purpose and need of the project (i.e., if the
project is specifically planned to stimulate growth). For instance, projects on new
location near urban areas often have the greatest potential for cumulative impacts
since they provide improved access to previously inaccessible sites. A narrative
cumulative impact analysis prepared using the methodology outlined in the
DOT1DENR NEPA/SEPA Cumulative Impacts Guidance document mentioned earlier
should generally suff ice to answer this question. If the answer to this question is "no",
then no further analysis is needed and the narrative (qualitative) analysis should be
sufficient.
b. Are existing uses of the water (as reflected in the classification of the waters
likely to be impacted by the -growth? The following descriptions (categories 1, 2
and 3) should help clarify the answer to this question.
1 . Water Supply, HQW and ORW classifications -DWQ has several existing
regulatory programs that address cumulative impacts for these waters.
Specifically, the Water Supply Protection Program as well as the
watershed -specific management plans for ORW and HQW watersheds
provides considerable protection from cumulative impact on downstream
water quality. In addition, DWQ often relies on other state permitting
programs such as the High Quality Waters Best Management Practices
developed by the Division of Land Resources for protection of water quality.
DOT reports for projects impacting these waters should describe and
analyze these existing programs for a particular project. In most cases, a
narrative analysis based on the DOT/DENR NEPA/SEPA report with clear
reference to these existing DWQ permitting program as well as a
description of the general effectiveness of these programs in protecting
water quality should be sufficient. However, if DWQ staff determines that a
project appears to have growth -stimulating effects and downstream impacts
1 These documents will need to be revised to explicitly refer to water quality -related issues for the 401 Certification and
Isolated Wetland Permitting Programs. In the interim, DWQ believes that the procedures outlined in these documents will
normally suffice for cumulative impact analysis for these projects.
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that are not addressed by existing regulatory programs, then a quantitative
analysis may be required.
2. Class C, B, SC and SB classifications — The potential for cumulative
analysis from these projects should be discussed utilizing the qualitative
analysis described above for these stream classifications. If significant
potential for cumulative impact is identified (for instance due to the
presence of endangered aquatic species), then a quantitative analysis may
be required.
3. Impaired Waters (303 (d) listed Waters), SA (Commercial Sheiffishing), and
Trout classification — These watersheds warrant special attention with
respect to cumulative impact analysis since existing regulatory programs
often have not adequately addressed pollution sources for these waters.
With respect to the impaired waters, the reported parameter of concern and
source (for instance, point versus non -point) of the contaminant should be
examined to determine if the new location road and any induced
development are likely to further impact these waters. For instance, if the
impaired water is listed as impacted by dioxin from point sources, it is very
unlikely that a new road and its associated development would exacerbate
the situation. In this case, a qualitative analysis of cumulative impacts will
usually suffice. However, for Trout and SA waters as well as impaired
waters which are impaired by pollutants likely increased by development
(such as bacteria, nutrients or sedimentation), then a detailed, quantitative
analysis should be conducted by DOT to determine 1) if cumulative impacts
are likely and then (if impacts are predicted to occur) as well as 2) what
non -point source control measures will be needed and how they are to be
implemented. This analysis will often require watershed -level modeling
using export coefficients, estimated levels of treatment for BMP's and
comparison to numerical water quality standards or numeric water quality
goals. With respect to implementation, discussion with and commitment
from local governments may be needed to address these cumulative
impacts.
regulatory pro -grams which can address these Impacts?). For instance, the
Phase 11 NPDES Stormwater Permit Program addresses stormwater runoff from
development as do riparian buffer rules in place in several watersheds across the
state. Finally in some cases, local governments already have land use control
programs in place that adequately address stormwater runoff. In many cases,
these programs should reduce or eliminate the need for additional regulatory
measures. Modeling may be needed to determine the effect of these existing
programs.
If the answers to all three questions of these questions are yes, then a quantitative
analysis of cumulative impact would be needed for the 401 Water Quality Certification. The
following information describes this process in more detail
2. Analytical considerations for quantitative analyses:
a. Impact or service area — The area chosen for detailed study should be selected
by DWQ after consultation with local planning experts and the applicant. The area should
be limited to the downstream location most likely affected by the growth induced as a
result of the project. Boundaries such as major rivers, major physiographic constraints
and already developed areas should be used as appropriate. For instance in some
instances, a seven -mile distance from the road on new location has been used to put
boundaries on the study area.
b. Modeling considerations — The selection of models and their study plan must be
approved by DWQ before their use. The model must be in the public domain and include
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water quality parameters -of concern for the water body. An examination of the
effectiveness of various land use control scenarios would also be helpful in evaluating the
cumulative impact of a project on downstream water quality.
c. Time frame for analysis — DWQ's approval of a time frame for analysis must
hinge on what is "reasonably anticipated" as noted in the 401 Certification and Isolated
Wetland rules. Local land use experts should be consulted for their expertise in the local
area. The analysis should (if possible) consider several time frames including a) known
proposed projects, b) 10 years, and c) 20 years. The final determination of the appropriate
time frame should be done by DWQ staff based on the "reasonably anticipated" criteria.
d. Non -point source (i.e., stormwater) measures to consider— Management of the
cumulative impacts of development on downstream water quality necessarily involves
stormwater management since stormwater is often the major source of these pollutants.
The local land use control measures to consider must be focused on the likely (or known)
cause of water quality impairment or concern. For instance in watersheds with
eutrophication issues, measures to manage inputs of nitrogen and phosphorus should be
considered. In watersheds where sediment is the concern, the measures that address
sediment from a) construction, b) developed landscapes, and c) streambank erosion must
all be evaluated.
Measures which often need to be considered include a) enhanced sedimentation and
erosion control BMPs and inspections, b) riparian buffers, and c) on-site stormwater
management, Where appropriate, these measures should utilize the various DWQ design
manuals or be patterned after other DWQ rules in order to ensure that the specific BMPs
are adequately designed, implemented and maintained to protect downstream water
quality.
Other publiely4unded development projects
Other publicly funded development projects may or may not result in cumulative impacts. For
instance, the development of a regional, public park or a new library is unlikely to result in
cumulative impacts. For these projects, a generic description similar to that described in step
I A above should suffice. However, other projects Will likely result in cumulative impacts and
therefore, then either a qualitative cumulative impact analysis (see I B above) or (more rarely)
a quantitative analysis (see I C above) should be required of the applicant. Examples of
projects in this later category would be projects targeted to encourage development such as
the Global TransPark.. DWQ staff should use their professional judgment to determine if a
publicly funded project is likely to result in cumulative impacts and would then need a
quantitative analysis of this impact.
Ill. Private development projects
Privately funded development projects are normally not subject to SEPA or NEPA and
therefore, only rarely require formal environmental documentation. However, if these projects
require 401 Water Quality Certification or an Isolated Wetland Permit, then the cumulative
impact provisions of the Water Quality Certification and Isolated Wetland Permit rules are
applicable.
Many private development projects are unlikely to cause cumulative impacts, including projects
such as urban in -fill, most residential subdivisions, and small commercial developments as well
as agricultural and silvicultural operations that may need permitting from DWQ. However, some
private projects may cause significant cumulative impacts on water quality. In these cases if a
401 Water Quality Certification or Isolated Wetland Permit is required, then either a qualitative
or quantitative analysis of cumulative impact would be needed.
Some private development projects can clearly result in cumulative impact. Recent examples of
this effect include the Streets at South Point Mall in Durham and the Landfall development in
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Wilmington. Often these developments are 1) relatively large, 2) involve commercial
development, and 3) occur in otherwise relatively undeveloped landscapes with an impact on
regional growth patterns. When these or similar characteristics are present with a private
development project, then DWQ staff should use the guidance outlined in Section I.C. above to
determine if a quantitative analysis of cumulative impacts is needed or whether a qualitative
analysis will be sufficient.
IV. Decision making and Elevation Process
DWQ staff will use the three tiered system outlined above to decide what level of cumulative
impact analysis is appropriate for a given project. This action will normally occur during a pre -
application meeting or in the initial review of a project to help ensure that these analyses do not
cause an undue delay in a project.
A. Elevation Process for DOT proiects — If, after review of the information provided by DOT
and the methodology used to produce it, DWQ technical staff disagrees with the analysis
of growth -stimulating effects and downstream impacts contained in the narrative or
qualitative analysis, then DOT and DWQ will implement (upon DOT's request) an elevation
process to resolve the issue. A review panel will be established comprised of the Water
Quality Section Chief, the Wetlands/401 Unit Supervisor and the DOT project coordinator
from DWQ as well as the PDEA Branch Managers a representative from the Project
Development Branch, a representative from the Office of Human Environment from DOT
and consultants who prepared the report. This review panel will convene and review the
available materials to determine whether the proper methodology and analysis were used
or whether the correct conclusion was made regarding the growth -stimulating effects of
the project. DWO expects to work via consensus with these parties. However, the
ultimate decision as to what type of analysis is needed must remain with DWQ.
B. Other awlicants - If other private or public applicants do not concur with a decision made
by DWQ staff with respect to the level of cumulative impact analysis, the applicant may
request a meeting with the Wetlands/401 Unit Supervisor (or the appropriate Branch Chief
if the initial decision was made by the Unit Supervisor) and other relevant DWQ staff as
well as the applicant and all relevant consultants. DWQ expects to work via consensus
with these parties. However, the ultimate decision as to what type of analysis is needed
must remain with DWQ.
V. Implementation of Measures to Address Cumulative Impact
If the above analyses (especially the quantitative analysis) reveal that additional measures are
needed within a specific geographic area in order to address downstream water quality impacts of
the project and associated growth, the IDWQ will work with the local municipalities to develop and
implement local land use control measures which will address the water quality impacts. Based
on DWQ's experience with the water supply watershed protection rules, NPDES Stormwater
Permitting and riparian buffer protection rules, DWQ believes that these decisions are most
efficiently made at the local level. DWQ staff will work actively with all interested local entities to
help ensure the timely implementation of any needed ordinances. In the unlikely event that a
local government is unable or unwilling to implement the needed protections, DWQ will examine
its existing regulatory responsibilities (including, but not limited to, the 401 Certification Program
and NPDES Stormwater Permitting Program) to determine what measures DWQ can undertake to
provide the needed protection for downstream water quality.
Finally, DWQ believes that once the appropriate land use control measures are in place for a
specific area, then these actions should adequately address cumulative impact concerns for that
geographic area for future projects. Therefore, other development projects should be able to rely
on the previous analysis and land use management actions rather than each project conducting
their own, separate analyses as long -as the basic conditions under which the land use
management measures were designed and implemented have not changed.
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