The Glen Canyon Dam EIS:
Random Thoughts And Revelations
Brian Dierkers Flagstaff ski shop is always an
interesting place to hang out, a place where river reprobates gather and share recent
events, re-bond, tell lies, and sometimes plot against government inadequacies. It was
there a few months ago that Brad Dimock found me recovering from one of those recent
events and asked what was happening on the EIS. His exact words, I think, were, What
do the money grubbers want to do with the river now? My answer surprised Brad and
several other guides listening to our exchange.
In my opinion, this is one environmental impact statement with which we will
be pleasedbecause the opportunity exists to operate Glen Canyon Dam to the benefit
of virtually all downstream resources. Brad was surprised with my level of confidence in
the process. One thing led to another and pretty soon I had agreed to tell it
all in the next issue of The News.
First, a little background. During the spring of 1991 I was retained by the
Hopi Tribe to represent them as a member of the EIS team. Hopi interests in the Canyon are
truly holistic. They seek a spiritual and resource-protective balance within a system that
they believe has been insulted by placement of the Dam. However, they do not believe
removing the Dam and returning to the way it was is a viable or realistic
option. In their view, all of mankind and the balance of universal stability will be
served by providing maximum protection to the cultural and natural resources of the river
The team I joined is a loose coalition of diverse interests, consisting of
representatives from the following agencies: the Hopi and Hualapai tribes; Navajo Nation;
Arizona Game and Fish Department; U.S. Fish and Wildlife Service; United States Geological
Survey; Bureau of Reclamation; Western Area Power Administration and the National Park
Service. Its a big group with a big responsibility. Our job is to develop and
analyze alternative water release scenarios that will minimize impacts to downstream
resources. This is a complex task with some significant constraints. For one thing,
whatever scenario the EIS team comes up with it must conform to what is known as the
Law of the River. Among other things, this means that previously agreed upon
water allocations between the lower and upper basin states must be accommodated. Also,
hydropower is one of the resources we must consider, and to the extent possible, protect.
Though these goals may sound impossibly ambitious and conflicting, in my
opinion a pathway exists for achieving this delicate balance. Although I know others who
share many of the conclusions expressed in these pages, I want to make it clear that I
speak here as an individual, not as a representative of any agency or group.
The Glen Canyon Environmental Studies
Since 1982 the GCES program, led by the indefatigable David Wegner (one of
those remarkable U.S. Bureau of Reclamation scientists whose spirit is owned by Grand
Canyon), has dedicated its efforts to describing the cause and effect between dam
discharge patterns and the condition of all resources downstream. Important GCES findings
to remember as we review potential flow scenarios include:
- Once the Dam was in place, there was no turning back. The Colorado
was changed forever. The new river has given up its sediment to Lake Powell;
water temperatures are consistently cold summer and winter; and discharge patterns have
- Rare and damaging floods, like those of 1983 and the subsequent
high water through 1987, cause far more damage to the downstream resources than the daily
discharge patterns required to produce peaking power at the Dam.
- Plant operations in effect at Glen Canyon Dam prior to the
implementation of Interim Flows in August of 1991 depleted sediment and thereby damaged
cultural and ecological resources of the river corridor. Discharge patterns that could
peak at 31,500 cfs (power plant capacity before 1983), with no restrictions on ramping
rate (how fast releases from the Dam change), were clearly damaging to all resources
except hydropower production.
- The current Interim Flows (which will remain in effect until
changed through this EIS process) have allowed most of the resources damaged by earlier
floods and flow patterns to begin healing and stabilizing.
All the resources and findings of the Glen Canyon Environmental Studies,
including continual updates on research by their scientists, have been incorporated into
development of a series of possible dam management alternatives.
First, lets look at options no longer under consideration. Early in
the EIS process, the following suggested concepts were discussed and abandoned as
1) Remove the Dam. This was simply judged not practicable, and to my knowledge none of the
Cooperating Agencies or individuals involved think dam removal is a viable option.
2) Build another dam downstream from Glen Canyon Dam near Lees Ferry. Initially, there was
a lot of support for this from the power interests. The new re-regulation dam
would contain the power-related daily fluctuations and release relatively steady flows
downstream. Permanent loss of the last 15 miles of Glen Canyon was only one of the reasons
this alternative was not considered further.
3) Mimic pre-dam flows. This reflects the romantic notion that if we just let the same
amount of water through the flood gates of Glen Canyon Dam that passed during the pre-dam
era, all the problems would be solved. There are a couple of serious problems with this
idea. First, without the old sediment loads, pre-dam discharges would simply scour out the
remaining beaches. Second, they would also destroy existing power production capacity
without benefiting any other resourcean unacceptable option.
Now, lets move on to more realistic possibilities. There are presently
eight alternative flow scenarios being considered in the draft EIS (Table 1). Two of the
eight are immediate throwaways: the No Action and the Maximum Power Plant Capacity
No Action. The guidelines for preparing National
Environmental Policy Act (NEPA) documents require an in-depth analysis of leaving the
system as ishence, No Action. In the case of Glen Canyon Dam and the Grand Canyon,
changing nothing would result in continued decay of natural and cultural resources,
defeating the reason for an EIS in the first place. Thus the No Action alternative is
unlikely to be considered as an option when the final decision is made.
Maximum Power Plant Capacity. This alternative would
exacerbate existing destructive conditions. It is just like the No Action alternative,
with the exception that peak discharges could reach 33,200 cfs, the power plants
maximum capacity, rather than the operating limit of 31,500 cfs.
The six remaining alternatives can be divided into two basic groups. The
first, the Restricted Fluctuating Flow Alternatives, includes low, moderate, and high
daily fluctuations. The second, the Steady Flow Alternatives, includes a year-round steady
flow, a seasonally adjusted steady flow and a monthly steady flow.
One of the commonly held beliefs regarding the Dam and its impact on the
Grand Canyon is that daily fluctuations in discharge are bad. Following this notion is the
belief that if daily fluctuations are bad, then steady flows are good. As with most
generalities, things are not quite so simple. All studies to date seem to indicate that
some daily fluctuations can occur without directly compromising natural and cultural
resources, with the possible exception of native fishes. Their reactions to changes in
discharge remain unclear. Nevertheless, two camps have developed regarding future
discharge patterns. The majority opinion holds that daily fluctuations with significant
restrictions would be acceptable for both environmental protection and hydropower
production. The other opinion maintains that fluctuating flows are unacceptable (mostly
because of perceived impacts on fishes), and that steady flows are required despite the
limitations they place on power generation.
The Fluctuating Flow Alternatives
High Fluctuating Flow is so similar to No Action that it
accomplishes little in the way of changing the existing impacts.
Moderate Fluctuating Flow begins to control the ramp rate,
which is known to affect rates of beach erosion, but it still allows peak flows to reach
31,500 cfs. During low-water years maximum flow would not exceed 22,300 cfs.
Low Fluctuating Flow restricts the low discharge to 8,000
cfs during the day and 5,000 cfs at night and the high, to 20,000 cfs. This alternative
also includes a habitat maintenance spike of high water (31,500 cfs for 7-14 days) during
spring of each year. The intention of this pulse of high water is to redistribute sediment
within the backwaters. Ramp rates are contained within a 2,500 cfs/hr change as the river
rises and no more than 1,500 cfs/hr as it drops. Compared to what the resources and the
river running community have dealt with in the past, this is a pretty mellow river.
Actually, this alternative is very similar to existing Interim Flows, and GCES scientists
have demonstrated that Interim Flows have benefited most critical resources (including
Steady Flow Alternatives
The objective of the three steady flow alternatives is to provide
relatively constant flows on either a monthly, seasonal or yearly basis.
Existing Monthly Volume calls for flows to be adjusted at
the beginning of each month, then remain steady until the beginning of the next month.
Seasonally Adjusted Steady Flow attempts to follow more of a
natural hydrograph, with constant low flows in winter and higher flows in the
spring and summer.
Year-round Steady Flow provides for constant releases all
year, with the discharge determined in advance by what is predicted to flow into the
system. For example, if 8.23 million acre feet of inflow were expected for the year, an
unchanging discharge of 11,400 cfs would occur day and night, month after month.
One of the problems with the steady flow alternatives is that they depend on
accurate forecasts of runoff and of the amount of storage space available in Lake Powell.
However, to be perfectly honest, the main problem with all the steady flow alternatives is
that they are not good for natural ecosystem processes and they destroy flexibility in the
Dams hydropower production capacity. At this time, there appear to be no
environmental benefits to steady flow alternatives that cannot be achieved through one or
more of the restricted fluctuating flow scenarios.
The Common Elements
Though the six alternatives described above are wildly different in their
extremes, in some ways, a great victory will be won for protection of Grand Canyon
resources with the selection of any one of them. How is that possible? The answer lies in
provisions built into all the discharge patterns that are guaranteed to improve the
condition of downstream resources. The elements common to them all are:
- Adaptive Management. This requires that from now on the system
will be under continual study. If data scientifically demonstrates that the selected
discharge pattern compromises environmental resources, the pattern can be altered (see the
article by Dave Wegner in this issue).
- Flood Frequency Reduction Measures. The frequency of flood
releases (flows greater than 40,000 cfs) would be reduced to 1 in 100 years. This would
likely be accomplished by permanently installing 4.5 foot flashboards on the dam
spillways. This action is meant to provide some insurance against the kind of flood that
occurred in 1983.
- Habitat- and Beach-building Flows. Under low fluctuating and
steady flows, it has been demonstrated that backwaters, which are important fish habitat,
can slowly fill with sediment. This damage can be reversed and these habitats maintained
by annually releasing pulses of high water (within power plant capacity) lasting one to
two weeks. It has also been suggested that once the bed of the river accumulates
sufficient sediment, flows in excess of power plant capacity (as much as 45,000 cfs ?) for
several days could actually re-build beaches.
- Studies on a Multilevel Intake Structure. Studies will continue on
impacts of selectively withdrawing water from different levels in reservoir to warm the
river. One of the big unknown issues is what this would do to the native fishery. It is
thought to be beneficial, but the jury is out.
- Protection of Cultural Resources. Except for reducing strong daily
fluctuations and floods, none of the alternatives can substantially influence, either
positively or negatively, the archaeological sites that have been exposed by erosion since
the Dam. The EIS includes provisions for stabilizing sites or recovering data if the sites
cannot be saved.
One River Guide/Scientists Preferred Alternative
I like the Low Fluctuating Flow Alternative. Under this
flow scenario the following happens:
1) Sediment accumulates and long-term beach degradation stops.
2) Streamside vegetation stabilizes from the 20,000 cfs level up to the Old High Water
Line of pre-dam flows. This means lots of emergent vegetation for nesting ducks and
near-shore birds, and increased proliferation of willow, tamarisk, arrowweed and other
plantsa habitat we know to be highly productive for birds, small mammals, lizards,
amphibians and insects.
3) The rainbow trout fishery will do as well in this alternative as in the moderate
fluctuating flow or any of the steady flow alternatives. Data are insufficient to predict
what will happen to the native fishery.
4) Cultural resources are protected as much as possible.
5) River runners have a steadier river with less high and low water extremes and slower
rates of change.
6) Hydropower production flexibility is reduced, but not radically, and certainly less
than in any of the steady flow alternatives.
The Dispute Goes On
The unknown future of the native fishery is the primary reason there is
yet dispute within the EIS team over selection of the Preferred Alternative. The choice
has narrowed to the Low Fluctuating Flow Alternative and the Seasonally Adjusted Steady
Flow Alternative. The former does good things for almost every resource, including power;
the latter does good things for almost every resource except power. The main argument for
the Seasonally Adjusted Steady Flow regime is that it may improve the native fishery. More
studies are needed to know for sure how native fishes will fare under any change, and I
for one opt to allow the adaptive management process combined with the Low Fluctuating
Flow Alternative to make this determination.
A Draft Environmental Impact Statement will be made available for public
comment during the summer of 1993, and though that is six months away, it is not likely
there will be major changes from what we know today. The ultimate decision on the future
water release patterns from Glen Canyon Dam will be made by the Secretary of the Interior,
and the really good news is that the Secretary is none other than our own Bruce Babbitt, a
man whose leanings toward protection of Grand Canyon are well known.
When the Draft EIS hits the street, please review it and let the powers that
be know your opinion. Have a good river trip.