A presentation on how to write a cumulative impacts analysis under the California Environmental Quality Act

1. Practical Approaches for Defensible
Cumulative Analyses Under CEQA
Presentation by: Tania Treis
9/28/2016

2. What are Cumulative Impacts and Why
are they Considered

3. Definition of Cumulative Impacts
Compounded impacts from separate projects that
increase overall environmental impactsWHAT
Otherwise overlooked in individual analysesWHY

4. Cumulative Impact Examples

5. Why is the Cumulative Analysis so Hard?
How do I quantify
effects with so many
unknowns?
Why did I leave this
section to the very very
end?? Now I have analysis
fatigue and just want to
be done!
How do I mitigate for a
small contribution to an
overall affect? Is my
project mitigation good
enough?
How do I quantify effects
with so many unknowns?
How do I determine if a
project has a significant
incremental contribution?
How do I even use this
“summary of projections”
approach?
How am I ever going to figure
out all of the projects that could
be relevant and describe them
all?

6. Structure of this Session
1. What is the List Approach vs.
Summary of Projections Approach
• List approach
• Planning projections
2. Determining Significance of Cumulative Impacts
• Criteria
• Two-step approach
3. Mitigating for Cumulative Impacts
• Project mitigation good enough?
• Paying Fair Share
4. How-To Guide for Creating a Sound Cumulative Analysis

7. The List Approach and the Summary of
Projections Approach

8. Two Approaches
List of past, present, and
probable future projects
Advantage:
straightforward
Disadvantage:
potentially under
inclusive
1
Summary of projections
contained in an adopted local,
regional or statewide plan, or related
planning document that covers
cumulative effects
Advantage:
may be more
comprehensive
Disadvantage:
projects may not
be up-to-date
2

9. List Approach
What
projects to
include
Any project that could have combined effects
Projects should at least be in a planning stage –
don’t have to consider speculative projects
Level of
detail
Not expected to have same level as proposed project
Enough info to disclose severity of impacts and likelihood
of occurrence
Geographic
extent
Not so broad as to dilute impact significance
Overall list may be parred down by resource parameter
Moving
targets
New cumulative project after Draft EIR released
May need to define a timeline in EIR

10. Summary of Projections Approach
Adopted
plans
Base cumulative impact analysis on a summary of projections contained
an adopted local, regional, or statewide plan, or adopted EIR
for plan
Projects
may be
outdated or
inaccurate
Supplement with a regional modeling program
Use hybrid approach – supplement with list of projects outside of the plan
document
Use Tends to be used more often for
urban development

11. Exempt
• If cumulative impact was assessed in an EIR for a
community plan, zoning action, or general plan and
project is consistent with the plan – cumulative impacts
do not need to be addressed further
– Agency must find that cumulative impacts are already
“adequately addressed” in certified EIR
• Streamlining provisions of Pub. Res. Code § 21083.3 and
Guidelines § 15183 (specific streamlining provisions for
projects consistent with the development density
established by existing zoning, community plan, or
general plan policies for which an EIR was certified)
• SB 375

12. Determination of Significance

13. Consideration of Significance of Cumulative Impacts
• In most cases use same criteria as for
the proposed project
• Two-step method
Are the impacts of all the
projects together cumulatively
significant
Is the project’s contribution
cumulatively considerable?
Less than Significant
Cumulative Impact
No
Yes
Yes
No
Mitigate
1.
2.

14. Consideration of Significance of Cumulative Impacts
• Subjective – no guidance
• Can’t use ratio argument
• Not necessarily any level of contribution is significant
– Look at environmental setting
– Sensitivity of the resource
– Extent of project’s contribution
• The worse the problem, the more likely a minor
contribution could actually be cumulatively considerable

15. Qualitative vs. Quantitative Analyses
• Quantitative analysis is more defensible,
but not always possible
• What impacts can be quantified
– Air quality
– Groundwater usage
– Traffic
• If can’t be quantified
– Explain why – data not available or not reasonable to obtain
– Well-reasoned qualitative approach should be presented
• Do not assume impacts of other projects
can be mitigated

16. Mitigating for Cumulative Impacts

17. Mitigation Techniques
Project-specific mitigation
may work
Ex. Sedimentation and erosion
• Several construction projects
at once could result in
polluted runoff that causes a
significant cumulative water
quality impact
• Project’s mitigation includes
stormwater BMPs and
collection and treatment of
stormwater on-site.
New mitigation to avoid
contributions by project
Ex. Cumulative noise
• Overlap of projects could
increase noise beyond
thresholds
• New mitigation could be
added to avoid constructing
during period of overlap

18. Mitigation Techniques
Fair share
into a fund
Ex. Payment into a fund
• Pay into a fund to reconfigure
a traffic intersection that is
impacted by several projects
• Mitigation must actually result
– not just fees
Adoption of
an ordinance
“The only feasible mitigation
for cumulative impacts may
involve the adoption of
ordinances by regulations
rather than the imposition
of conditions on a project-by-
project basis."[Guidelines §
15130(c).]”

19. The Steps to Prepare a
Cumulative Analysis

20. Steps
Decide on list vs. projections1

21. Steps
Determine the list
of projects or projections
• Think of all jurisdictions
• Describe these projects in a
table and provide a map
• Or research plans and list
out projections to use
– General Plans
– Specific Plans
– Local Coastal Plans
– Regional
Transportation Plans
– Plans for reduction of
GHGs
2

22. Steps
Determine environmental parameters affected
and impacts that should be considered3
3

23. Steps
Define the significance criteria to
carry forward
4

24. Steps
Define the geographic scope by parameter and
the subset of projects by parameter
• Air Quality: whole air basin
• Geology: immediately adjacent – impacts confined
• Hydrology: watershed
• Noise: 0.25 miles – distance by which noise impacts can
combine
• Traffic: mostly local
5

25. Steps
Discuss the impacts
• Describe the impacts of the proposed project
and cumulative projects
• Describe if there is a cumulatively significant impact
• If no, done
• If yes, describe if the proposed project has a
cumulatively considerable incremental impact before
mitigation
6

26. Steps
Determine mitigation, if needed
• If mitigation is required, look first if project-specific
mitigation is enough to reduce the incremental
contribution
• Paying fair share into est. mitigation
• Or significant and unavoidable
7

27. ….and finally
• Avoid the most common pitfall –
PROCRASTINATION
Include the cumulative analysis with
the section so that it is prepared by
appropriate author in a timely fashion

28. Example Analyses – Are they Adequate?
The potential impacts of the proposed project considered with
other cumulative projects would result in overdraft of the
groundwater basin; however, the project would contribute
only 1 percent of the total amount withdrawn, therefore, it’s
contribution would be less than significant.
The proposed pipeline could be subject to liquefaction and
strong ground shaking where the pipeline crosses San Pablo
Creek. Many of the potentially cumulative projects could also
be subject to these seismic effects, a potentially significant
impact because many of the projects would increase the
number of people potentially exposed to these hazards.
However, the project’s contribution to this impact would not
be cumulatively considerable because the project does not
include habitable structures or otherwise introduce new
people to the project area.
Vibration impacts from the proposed project would be
temporary and limited to the times when construction would
occur. A cumulative vibration impact could occur if
construction occurred at the same time as construction of
cumulative projects within 35 feet of the proposed project
(vibration impacts generally dissipate within 35 feet of the
equipment, see Table 3.11-11 in Section 3.11: Noise). It is
reasonable to assume that none of the other cumulative
projects would occur at the same time as the proposed project
and within 35 feet of the proposed project, as it would not be
feasible to undertake two projects with heavy equipment in
such close proximity. Therefore, cumulative vibration impacts
would not occur.