Practical Approaches for Defensible Cumulative Analyses Under CEQA

Presentation by: Tania Treis9/28/2016

What are Cumulative Impacts and Why are they Considered

Definition of Cumulative Impacts

Compounded impacts from separate projects that increase overall environmental impactsWHAT

Otherwise overlooked in individual analysesWHY

Cumulative Impact Examples

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?

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

The List Approach and the Summary of Projections Approach

Two Approaches

List of past, present, and probable future projects

Advantage: straightforward

Disadvantage: potentially under

inclusive

1Summary 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

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

Summary of Projections Approach

Adopted plans Base cumulative impact analysis on a

summary of projections contained in 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

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

Determination of Significance

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.

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

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

Mitigating for Cumulative Impacts

Mitigation Techniques

Project-specific mitigation may workEx. 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 projectEx. Cumulative noise• Overlap of projects could

increase noise beyond thresholds

• New mitigation could be added to avoid constructing during period of overlap

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).]”

The Steps to Prepare a Cumulative Analysis

Steps

Decide on list vs. projections1

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

Steps

Determine environmental parameters affected and impacts that should be considered

33

Steps

Define the significance criteria to carry forward

4

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

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

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

….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

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.