WSP09906

• File Number: 8220.101.09
• Description: Glen Canyon Dam/Lake Powell
• State: AZ
• Basin: Colorado Mainstem
• Date: 11/1/1990
• Author: USDOI-BOR
• Title: Newsletter - Colorado River Studies Office - Vol.2
• Water Supply Pro - Doc Type: Publication

WHAT ALTERNATIVES DID THE PUBLIC RECOMMEND?

Out of the 17,000 written responses received 2,000
specifically discussed a particular alternative for study in
the EIS. Many people, in fact, recommended their
suggested alternative be the "preferred alternative."

Management of Glen Canyon Dam
Management of the Dam was a general category assigned
to comments that did not fit into another specific topic. A
total of 1,184 comments were made in this area. At the core
of concern is the management of water flows through the
power plant. Those who favor change, do so in a belief
that fluctuating flows and floods, especially those of
1983-84, are the cause of environmental damage.

There are two predominant views. One holds that the dam
management favors power production at the expense of
the downstream environment. The solution for this group
is to change the operation of the power plants and thus
the water releases from a peak power production system
to a base load, or constant flow, system. Others suggest
that higher minimum flows and lower maximum flows
might be adequate to mitigate environmental damage
down stream.

The alternative view states downstream problems can be
addressed within a framework which leaves the operation
of water flows through the powerplant for peaking
essentially unchanged. Under this view, the dam can be
operated to meet multiple objectives without serious
environmental damage.

Some commentors suggest no change is needed and the
operations should continue as presently constituted,
while others believe that criteria for management of the
dam should include priority for water storage and
delivery.

Ramping
Ramping rates, which is the rate at which flows are
increased or decreased, drew 274 comments. Most people
want reduced ramping rates, stating current rates

8

contribute to environmental damage associated with
fluctuating water flows.

Minimum flows
Comments on minimum flows were coded 223 times. The
most frequent comment was a request for higher
minimum flows somewhere between 5,000 to 8,000 cubic
feet per second (ds). Low minimum flows were blamed
for impacting fish, beaches, and river runners.

Maximum flows

Most comments in this category called for lower
maximum flows, generally not exceeding limits such as
20,000 to 25,000 ds. Maximum flows are blamed for
erosion of beaches and damage to campsites. There were
91 comments on maximum flows.

Interim flows
Flows during preparation of the EIS, generally called
interim flows by the public, drew 413 comments. They ran
the spectrum from no change to immediate and
permanent changes while the EIS is being prepared. The
current fluctuating flows were viewed as a cause of
environmental damage.

Other alternatives suggested
Several other alternatives were recommended by the
public including study flows, which primarily consist of
the study of all levels of flow including low, high,
fluctuating, and steady flows. Also suggested were:
seasonal flows, with most comments recommending an
examination of seasonally adjusted flows; operational
changes; strUctural and non-structural solutions, such as
a multiple outlet structure at the dam which would blend
water from different reservoir levels to increase the river
temperature and benefit endangered fish; sediment
augmentation in the river below the dam; and a "no
change from the present" alternative.