Contents
Boatman's Quarterly Review
Our acclaimed quarterly journal
Bookstore
Check out a title, buy a new book for the ammo can!
RealAudio from
Grand Canyon
Listen to Music inspired by the Canyon!
Adopt-a- Beach
Re-photographing critical beaches in Grand Canyon
Whale
Foundation
Ongoing support for an evolving community
Membership Info
You can, (and should) join us
Company Store
Various cool items you might be interested in. T-Shirts, hats,
posters, etc.
Grand Canyon Youth
River trips for youth
Links
People, Places, & Things
Protecting Grand Canyon
Setting the highest standards for the river profession
Celebrating the unique spirit of the river community
Providing the best possible river experience
Hey there- welcome aboard the
Grand Canyon River Guides Website. We want to tell you about ourselves,
what we do, and why you might care.
Who Are We? -- We're a group of folks who have fallen
under the spell of Grand Canyon and the Colorado River: a collection of
boatmen, crew and those who've joined us along the way-an association
of people who truly care about the River and her Canyon. We want to help
preserve, protect and defend the place and the magic it bestows on us
all.
In the late 1960's river running took off as a national pastime. Use levels
grew. River trips through Grand Canyon changed from a wild adventure to
a career path for many of us. At the same time, impacts from use and dam
operations became evident. As many of us watched, generations of bureaucrats,
environmentalists and outfitters came and went. We began to realize we
had a longer-term view of the place than many who managed it. It was time
to get off the boat and do something.
In 1988 a group of concerned boatmen, many with 15 to 20 years experience
on the River, came together to present a unified voice in defense of the
Canyon and the River experience. Grand Canyon River Guides, Inc. was born
as has since grown to around 1,800 members. Our goals, simply stated are:
- Protecting Grand Canyon
- Setting the highest standards for the river profession
- Celebrating the unique spirit of the river community
- Providing the best possible river experience
How Do You Fit In?-- About 800 of us are Guide Members,
having worked in the river business. The rest of us are General Members-folks
who have gone down the river with us or on their own, hiked, fished, researched
or generally fallen in love with the place. It's important for us to connect
with as many guides as possible, both commercial and private, so that
we may accurately
understand and represent the river industry's feelings. It's also important
for us to keep in touch with the river-running public. We want to keep
your memories and feelings for the Canyon alive. We need your help in
convincing the powers that be to act for the good of the Canyon. And,
of course, your financial support enables us to pursue ever greater goals
and challenges.
We are a 501(c)3, non-profit organization-your dues and contributions
may be tax deductible. We invite you to join us today. Could be the best
river trip you ever went on!
Glen Canyon Report - July 2008
Glen Canyon Dam Operations
The monthly release volume in July 2008 will be scheduled to be 865,000 acre feet. For
the first two weeks of July, weekday releases will average about 13,800 cfs with
afternoon peaks to about 17,500 cfs and off peak lows to about 9,500 cfs. Saturday and
Sunday releases will average about 13,000 cfs with afternoon peaks to about 17,250 cfs
and off peak lows to about 9,500 cfs. After July 14th, weekday releases will average
about 14,500 cfs with afternoon peaks to about 18,000 cfs and morning lows to about
10,000 cfs.
Monthly releases are being managed to prepare for a steady flow experiment to be conducted in September and October of 2008. The release volume for August will be adjusted in the range from 840 KAF to 890 KAF in order to target a release volume of 700 KAF for September which would result in steady flows of approximately 12,500 cfs. The release volume for September may be adjusted if necessary to achieve a projected Lake Mead elevation of 1105 feet above sea level by the end of water year 2008. The release volume for October will be adjusted to match the steady flow conditions that occur in September.
Releases from Glen Canyon Dam for the remainder of water year 2008 will be governed by the Equalization Tier of the Interim Guidelines for the Operation of Lake Powell and Lake Mead (Interim Guidelines). Under the Equalization Tier, the water year annual release volume can be above 8.23 million acre-feet (maf). For the July 2008 24-Month Study, the controlling Equalization objective for water year 2008 is an end of water year Lake Mead elevation of 1,105 feet above sea level. To achieve this objective, the water year annual release volume from Glen Canyon Dam will be controlled as practicably as possible to achieve an end of water year elevation at Lake Mead of 1105. The July 2008 24-month study projects the annual release volume from Glen Canyon Dam that would accomplish this objective to be 8.965 maf which equates to an equalization volume (volume in excess of 8.23 maf) projected to be 735,000 af. These projected values, as well as the monthly release volumes, for the remaining months of water year 2008 will be adjusted as conditions change.
Inflows to Lake Powell in early June increased to over 75,000 cfs with the elevation of Lake Powell increasing at nearly 1 foot per day. The current elevation of Lake Powell (July 6, 2008) is 3,632.64 feet above sea level. The Castle Rock Cut became passable in early June for the first time in over 5 years. The elevation of Lake Powell will likely reach its peak for water year 2008 by early August at approximately 3635 feet above sea level.
Upper Colorado River Basin Hydrology
Precipitation in the basin above Lake Powell was below average in June (70% of
average). The precipitation above Lake Powell in March and April was below normal at
60% of normal over the 2 month period and was average in May (100% of average). The
overall precipitation in the Upper Colorado River Basin for water year 2008 so far is
104% of normal. Temperature conditions in June were below normal to begin the month
but ended the month above normal.
The unregulated inflow to Lake Powell in May was 3,612,000 acre-feet (117% of normal). This was 188,000 acre-feet below the level forecasted in early June. The April through July unregulated inflow forecast for Lake Powell has been decreased from 9.2 maf (issued for June update) to 8.8 maf (issued for July update) which is 111% of average.
Upper Colorado River Basin Drought
The Upper Colorado River Basin is experiencing a protracted multi-year drought. Since
1999, inflow to Lake Powell has been below average in every year except one.
In the summer of 1999, Lake Powell was essentially full with reservoir storage at 23.5
million acre-feet, or 97 percent of capacity. Inflow to Lake Powell in 1999 was 109
percent of average. The manifestation of drought conditions in the Upper Colorado River
Basin began in the fall months of 1999. A five year period of extreme drought occurred
in water years 2000, 2001, 2002, 2003, and 2004 with unregulated inflow to Lake Powell
only 62, 59, 25, 51, and 49 percent of average, respectively. Lake Powell storage
decreased through this five-year period, with reservoir storage reaching a low of 8.0
million acre-feet (33 percent of capacity) on April 8, 2005.
Drought conditions eased in water year 2005 in the Upper Colorado River Basin. Precipitation was above average in 2005 and unregulated inflow to Lake Powell was 105 percent of average. Lake Powell increased by 2.77 million acre-feet (31 feet in elevation) during water year 2005. But as is often the case, one favorable year does not necessarily end a protracted drought. In 2006, there was a return to drier conditions in the Colorado River Basin. Unregulated inflow to Lake Powell in water year 2006 was only 71 percent of average.
Water year 2007 was another year of below average inflow with unregulated inflow into Lake Powell at 68 percent of average. Over the past 8 years (2000 through 2007, inclusive), inflow to Lake Powell has been below average in all but one year (2005). Drought conditions have eased again in water year 2008 with projected inflows to the main stem Colorado River reservoirs at or above normal. Reservoir storage in the Colorado River Basin, however, is still below desired levels with the overall Colorado River system storage (above Lake Mead) projected to be about 58% of capacity at the end of water year 2008.
Reservoir storage in Lake Powell and Lake Mead has decreased during the past 8 years
but is projected to increase by the end of water year 2008. Current reservoir storage in
Lake Powell is 62 percent of capacity. Storage in Lake Mead is 46 percent of capacity.
Updated: June 8, 2008
Rick Clayton