It’s about Disclosure: the Misplaced Fear of Cumulative Environmental
Impacts under CEQA
Robert Shibatani
Technical Director, Special Water Projects
EIP ASSOCIATES, a Division of PBS&J
Original Manuscript March 2005 (Amended May 2006)
As continual pressures are applied to California’s existing and finite natural resources, resource
managers have become increasingly sensitive to the importance of broadly addressing the stresses
impinging upon these valuable societal assets. As a result, new contemporary approaches to
resource analysis and protection are constantly being developed. Over the past 20-years, these
have included watershed or basin-level planning, integrated resource management (IRM)
planning, multiple resource integration, ecosystem analysis, and a host of others. A fundamental
tenet of each of these various approaches, however, is the genuine acceptance of the need to focus
on potential cumulative impacts.
While the concept of cumulative impact analyses has been around for years, there still exists a
wide divergence of approaches on how to conduct the analysis and on what results to present. All
too often this variation stems from an inherent misunderstanding of what actually constitutes a
cumulative impact. Moreover, because of this inadvertent misunderstanding, an unfortunate
result has been a basic misapplication of an important component required in this State’s only
environmental impact assessment statute (i.e., CEQA).
Under CEQA, cumulative impacts are, by definition, the collective impacts of any number of
known and reasonably foreseeable projects (or actions). They represent those likely impacts that
would result from the cumulative implementation of all known present and future projects or
actions. Since it includes future projects, there is ostensibly a temporal component. One is
compelled to look into the future to identify those reasonably foreseeable projects that would, or
could, conceivably impart an impact to any particular resource.
Most importantly, the listing of reasonably foreseeable projects must include not only those of the
Lead Agency, but also every other known project proponent. These other proponents need not be
of the same genre as the Lead Agency. Any agency (proponent) who, by their known or
reasonably foreseeable action(s), causes or has the potential to cause an impact to a resource must
be included in a cumulative impact assessment. This last requirement is one that is sometimes
overlooked. A proper cumulative impact analysis must include not only your present and
reasonably foreseeable future actions, but also those of everyone else. Without that degree of
inclusion, the evaluation becomes an assessment of only your collective future impacts and not an
assessment of all collective projects; which is the definition of a genuine cumulative impact
analysis.
When assessing cumulative impacts, three key elements must be addressed. First, one must look
concurrently at the specific resource in question as well as the complete listing of known and
reasonably foreseeable future projects. Both of these are closely related. Cumulative impacts, as
we have defined them here, will be different, depending on which natural resource we are
discussing. But each impact starts or, is manifested by a specific project action; therefore, a close
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review of each project must be made. Distinct projects will affect particular resources differently;
so it is very important to look at this first element mutually.
Second, as noted previously, cumulative impacts, again by definition, must have a temporal
component. Typically, most projects are identified in a variety of planning documents (e.g.,
General Plans, Master Plans, Capital Improvement Plans, etc.) each with defined time horizons.
These time horizons, usually set the upper temporal limit for the cumulative analysis (e.g., Buildout for General Plans).
Third, one must consider the spatiality of a cumulative effect; this too will vary by individual
resource. For some resources and, depending on their interconnectivity, a wide spatial context
warrants consideration. As an example, the federal Central Valley Project (CVP) coordinates its
reservoir and river operations across an entire hydrologic system. In this example, a hydrological
impact (e.g., reduced monthly storage) to Folsom Reservoir has ripple effects as far north as
Shasta Reservoir, south through the Sacramento-San Joaquin River Delta, and presumably
through the entire State Water Project. This is because the CVP is delicately coordinated with the
SWP, Bay-Delta Accord, and a variety of instream flow standards set forth in mandated
Biological Opinions. A proper cumulative impact analysis from a project that only proposed to
withdraw water from Folsom Reservoir would, therefore, need to address at a minimum, impacts
(or changes) to hydrological operations CVP-wide.
With the recognition and identification of these key elements, a proper baseline and cumulative
impact threshold can be established for each specific resource. The specific mechanics of a
cumulative impact assessment is discussed in a companion paper and, therefore, will not be
deliberated here.
With this level of analytical breadth (i.e., multiple projects, a far reaching temporal framework,
and an extensive spatial context), it is not unusual for a cumulative impact assessment to divulge
numerous significant effects. If done properly and recognizing the finite nature of many natural
resources in this, the most populous State in the country, it is also not surprising that significant
cumulative impacts do in fact exist. This fact raises an interesting trend and one that has, over the
years, and continues to pervade many CEQA documents.
There is often an improvident reaction of many Lead Agencies when required to make an impact
call for cumulative effects. As is their natural (and, in some sense understandable) tendency,
Lead Agencies often strive to avoid having to make significant effect determinations, where and
whenever possible. For cumulative effects, this tendency typically is the same. A large part of
this anxiety and, perhaps, uneasiness stems from the fact that a significant effect requires
mitigation. Mitigation measures are time consuming and can be extremely costly; Lead Agencies
know this better than anyone. Unfortunately, sometimes they mistakenly believe that by making
a significant effect determination for a cumulative effect, they would be obligated to identify and
implement mitigation measures to offset the entire cumulative effect; a highly impractical and,
dare I say, unfair proposition to say the least. In truth, such a requirement is clearly not what
CEQA requires them to do.
If one were to look at this pragmatically, one would easily see how inappropriate any such
requirement, if made under any law, would be. How could an individual Lead Agency ever be
expected to provide mitigation that would have any realistic probability of offsetting a cumulative
impact; especially given our understanding of how cumulative effects are defined? Asking one
agency to take on the responsibility of mitigating everyone else’s contributing effects simply
would not work; and fortunately, it is not what CEQA asks.
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CEQA has long since acknowledged the importance of the impact analysis. The “impactmitigation” association is a fundamental cornerstone of the statute. Where a Lead Agency
properly identifies, develops, and follows through with its mitigation commitments for all
significant impacts at the project-specific level, there is at least the expectation that the long-term
condition or state of the resources would, theoretically, remain unaffected. Essentially, if each
Lead Agency duly exercises their authority to meet their responsibilities to mitigate their own
impacts, then, so the theory goes, there should be no net harm in the long-term. There are,
however, many reasons why this theory has not worked, but again, that is the subject of another
equally interesting discussion.
The important point to note here, however, is that despite some failings, CEQA still does not ask
Lead Agencies to mitigate wide-ranging cumulative impacts that are above and beyond their
incremental contribution. In recognizing the importance of cumulative impacts, CEQA merely
asks that a Lead Agency undertake a legitimate good faith effort in characterizing the future
cumulative condition. Proper acknowledgement and documentation of this future condition is an
important responsibility of every Lead Agency.
By continually and accurately disclosing what the expected future cumulative condition holds, all
Lead Agencies are aiding in the development of a genuine informational base that can assist other
agencies (many of whom have specific mandates to deal with specific natural resources) to
effectively plan for long-term protection and, where possible, resource recovery. By meeting our
responsibilities to provide our part of that informational base, every Lead Agency will be
contributing towards responsible resource stewardship.
In closing, it can be said that a cumulative impact analysis is all about disclosure. For those of us
in the field of resource impact assessment as well as Lead Agencies, we need to conscientiously
and continually, dispel past notions about cumulative impacts and their required mitigative
actions. Past misunderstandings have prompted fear which has, in some cases, unfortunately
resulted in a forfeit of opportunities to develop the kind of valuable cumulative impact
information that long-term resource planners really need. Instead, we need to think of a
cumulative impact analysis as simply an important first step in the broader strategy to address
resource conservation, protection, and potential recovery in the long-term. Consistently accurate
and complete disclosures of cumulative impacts in CEQA documents will accomplish that
objective.
Robert Shibatani
Technical Director, Special Water Projects
EIP ASSOCIATES, a Division of PBS&J
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