Lake Mead

RobMcClain

RobMcClain

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C Dory Year
2006
C Dory Model
23 Venture
Vessel Name
Freedom
For those of you who occasionally enjoy the remarkable beauty of Lake Mead, the NPS just issued the alert I've copied below regarding use of the various launch ramps. We carefully launched there just 2 weeks ago and noted the water level was lower than we had ever seen. Back then - just 2 weeks - the main ramp nearby Lake Mead Marina was down to just 2 small narrow lanes. Today it is down to just 1 and I suspect it is no longer usable for a 22' C-Dory. The lake is at new historic lows not seen since it was originally filled.

Rob

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Lake Mead National Recreation Area News Release

Release Date: May 1, 2015


USE CAUTION WHEN LAUNCHING AT LAKE MEAD THIS WEEKEND


BOULDER CITY, Nevada -- Due to declining water levels at Lake Mead, launch ramps conditions have changed.
“Boaters should use caution when they launch at Lake Mead to ensure they’re on solid footing,” said Christie Vanover, public affairs officer. “The lake’s elevation is at 1,079 feet today. This is unknown territory for all of us.”

As the water declines and the condition of the ramps are revealed, crews are finding silt built up on top of ramps, which can cause vehicles to get stuck. In some locations, temporary concrete planks that have been resting 20-30 feet below the waterline have shifted and need to be readjusted.

In mid-May, contractors will begin installing permanent launch ramps. In the interim, the park’s road crew is working diligently to repair what they can to maintain boating access.

The conditions as of May 1 are as follows:

Echo Bay: Conditions are favorable here. There are four lanes on solid concrete planks. This area is ideal for deep water launching.

Callville Bay: Two lanes with temporary pipe mat remain open. The two lanes with concrete planks have been closed due to shifting.

Boulder Harbor: The six-lane launch ramp is permanent concrete down to elevation 1,060 feet; however, the channel to exit the harbor is only three-feet deep. Use extreme caution.

Hemenway Harbor: One lane remains open. The other lanes are closed due to silt build-up.

Temple Bar: Launching is difficult because silt has built up over the pipe mat. Crews will be making repairs.

South Cove: This launch ramp should have solid launching the afternoon of May 1. Crews have been building up a drop off and replacing pipe mat.

Boaters may want to consider storing their boats on the water in a slip at Lake Mead. Callville Bay, Las Vegas Boat Harbor and Temple Bar offer this service.

At Lake Mohave all launch ramps are open with excellent launching.

-NPS-
 
Powell is low for this time of the year, but not as low a 2005. The snowpack is reported at Snowpack is 47% of avg
TotalPrecip is 73.00% of avg. The level can be controlled by water release, but there are obligatory releases, for power generation, Grand Canyon flow, and by Treaty. I suspect that Castle Rock Cut off will not be usable a lot longer (although it is currently).

As we drove across the UTAH, Lower CO, and NM areas a couple of weeks ago, we were impressed by the lack of snow. Lake Powell is always fun, there will always be anchorages, and plenty of places to go.
 
I read that they are supposed to let more than the usual amount of water out of Lake Powell this year to help shore up Lake Mead.
 
Latest BOR update was April 15th

www.usbr.gov/uc/water/crsp/cs/gcd.html

Glen Canyon Dam / Lake Powell

Current Status
The unregulated inflow volume to Lake Powell in March was 552 thousand acre-feet (kaf) (83% of average). The release volume from Glen Canyon Dam in March was 649 kaf. The end of March elevation and storage of Lake Powell were 3,591.0 feet (109 feet from full pool) and 10.91 million acre-feet (maf) (45% of full capacity), respectively. The reservoir elevation is near the anticipated seasonal low and will soon begin increasing as spring runoff enters the reservoir.

Current Operations
The operating tier for water year 2015 was established in August 2014 as the Upper Elevation Balancing Tier. In the Upper Elevation Balancing Tier the initial water year release volume is 8.23 maf; however, there is the possibility for an April adjustment to equalization or balancing operations to govern for the remainder of the water year. This April 2015 24-Month Study establishes that Lake Powell operations will shift to “balancing releases” for the remainder of water year 2015. Under Balancing, the contents of Lake Powell and Lake Mead will be balanced by the end of the water year, but not more than 9.0 maf and not less than 8.23 maf shall be released from Lake Powell. Based on the most probable inflow forecast, this April 24-Month Study projects a balancing release of 9.0 maf in water year 2015; the actual release in water year 2015, however, will depend on hydrology in the remainder of water year and will range from 8.23 to 9.0 maf. The projected release from Lake Powell in water year 2015 will be updated each month throughout the remainder of the water year. Reclamation will schedule operations at Glen Canyon Dam to achieve as practicably as possible the appropriate total annual release volume by September 30, 2015.

In April, the release volume will be approximately 600 kaf, with fluctuations anticipated between about 7,500 cfs in the nighttime to about 13,000 cfs in the daytime and consistent with the Glen Canyon Operating Criteria (Federal Register, Volume 62, No. 41, March 3, 1997). The anticipated release volume for May is 700 kaf with daily fluctuations between approximately 8,500 cfs and 14,500 cfs . The expected release for June is 800 kaf with daily fluctuations between approximately 10,000 cfs and 18,000 cfs.

In addition to daily scheduled fluctuations for power generation, the instantaneous releases from Glen Canyon Dam may also fluctuate to provide 40 MW of system regulation. These instantaneous release adjustments stabilize the electrical generation and transmission system and translate to a range of about 1,200 cfs above or below the hourly scheduled release rate. Under system normal conditions, fluctuations for regulation are typically short lived and generally balance out over the hour with minimal or no noticeable impacts on downstream river flow conditions.

Releases from Glen Canyon Dam can also fluctuate beyond scheduled releases when called upon to respond to unscheduled power outages or power system emergencies. Depending on the severity of the system emergency, the response from Glen Canyon Dam can be significant, within the full range of the operating capacity of the power plant for as long as is necessary to maintain balance in the transmission system. Glen Canyon Dam typically maintains 27 MW (approximately 800 cfs) of generation capacity in reserve in order to respond to a system emergency even when generation rates are already high. System emergencies occur fairly infrequently and typically require small responses from Glen Canyon Dam. However, these responses can have a noticeable impact on the river downstream of Glen Canyon Dam.

Inflow Forecasts and Model Projections
The April to July 2015 water supply forecast for unregulated inflow to Lake Powell, issued on April 2, 2015, by the Colorado Basin River Forecast Center, projects that the most probable (median) unregulated inflow volume will be 3.75 maf (52% of average based on the period 1981-2010). The forecast decreased by 135 kaf since last month. At this point in the season, there is still uncertainty regarding this year’s water supply and the total inflow to Lake Powell. The spring runoff forecast ranges from a minimum probable of 2.60 maf (36% of average) to a maximum probable of 5.70 maf (80% of average). There is 10% chance that inflows could be higher than the maximum probable and a 10% chance they could be lower than the minimum probable.

As determined in the August 2014 24-Month Study, and documented in the 2015 Annual Operating Plan, Lake Powell’s operations in water year 2015 will be governed by the Upper Elevation Balancing Tier. In this tier, the initial water year release volume is 8.23 maf, however, there is the potential for an April adjustment to equalization or balancing releases in April 2015. This April 2015 24-Month Study projects the end of water year elevation at Lake Powell to be above 3,575 feet and the end of water year elevation at Lake Mead to be below elevation 1,075.0 feet. Therefore, in accordance with Section 6.B.4 of the 2007 Interim Guidelines, Lake Powell operations will shift to “balancing releases” for the remainder of water year 2015. Under Section 6.B.4, the contents of Lake Powell and Lake Mead will be balanced by the end of the water year, but not more than 9.0 maf and not less than 8.23 maf shall be released from Lake Powell.

Based on the April most probable inflow forecast, the annual release volume from Lake Powell during water year 2015 is projected to be 9.0 maf. Under the minimum probable inflow scenario, the water year release is projected to be 8.9 maf. Under the maximum probable inflow scenario, the release is projected to be 9.0 maf. There 10% chance that inflows will be lower than the current minimum probable forecast, potentially resulting in lower releases. If inflows are less than the minimum probable forecast, the water year 2015 annual release could be as low as 8.23 maf. If inflows are greater than the current forecasted maximum probable inflow, the annual release will be 9.0 maf. The projected release from Lake Powell in water year 2015 will be updated each month throughout the remainder of the water year.

Based on the current forecast, the April 24-Month Study projects Lake Powell elevation will end water year 2015 near 3,583 feet with approximately 10.24 maf in storage (42% capacity). Projections of elevation and storage still have significant uncertainty at this point in the season, primarily due to uncertainty regarding spring runoff and the resulting inflow to Lake Powell. Under the minimum probable inflow scenario, updated in April, the projected end of water year elevation and storage are 3574 feet and 9.45 maf (39% capacity), respectively. Under the maximum probable inflow scenario, updated in April, the projected end of water year elevation and storage are 3603 feet and 12.02 maf (49% capacity), respectively. Modeling of projected reservoir operations based on the minimum and maximum scenarios will be updated again in August.

Upper Colorado River Basin Hydrology
The Upper Colorado River Basin regularly experiences significant year to year hydrologic variability. During the 15-year period 2000 to 2014, however, the unregulated inflow to Lake Powell, which is a good measure of hydrologic conditions in the Colorado River Basin, was above average in only 3 out of the past 15 years. The period 2000-2014 is the lowest 15-year period since the closure of Glen Canyon Dam in 1963, with an average unregulated inflow of 8.39 maf, or 78% of the 30-year average (1981-2010). (For comparison, the 1981-2010 total water year average is 10.83 maf.) The unregulated inflow during the 2000-2014 period has ranged from a low of 2.64 maf (24% of average) in water year 2002 to a high of 15.97 maf (147% of average) in water year 2011. The water year 2014 unregulated inflow volume to Lake Powell was 10.381 maf (96% of average), which, though still below average, was significantly higher than inflows observed in 2012 and 2013 (45% and 47% of average, respectively). Under the current most probable forecast, total water year 2015 unregulated inflows to Lake Powell is projected to be 7.18 maf (66% of average), and ranges from a minimum probable inflow of 5.9 maf (55%) and maximum probable inflow of 9.4 maf (87%).

At the beginning of water year 2015, total system storage in the Colorado River Basin was 30.0 maf (50% of 59.6 maf total system capacity). This is nearly the same as the total storage at the beginning of water year 2014 which began at 29.9 maf (50% of capacity). Since the beginning of water year 2000, total Colorado Basin storage has experienced year to year increases and decreases in response to wet and dry hydrology, ranging from a high of 94% of capacity at the beginning of 2000 to a low of 50% of capacity at the beginning of water year 2014. One wet year can significantly increase total system reservoir storage, just as persistent dry years can draw down the system storage. Based on current inflow forecasts, the current projected end of water year 2015 total Colorado Basin reservoir storage is approximately 27.4 maf (46% of capacity). The actual end of water year storage may vary from this projection, primarily due to uncertainty regarding this season’s runoff and resulting reservoir inflow. Based on the April minimum and maximum probable inflow forecasts and modeling the range is approximately 26.1 maf (44%) to 29.5 maf (50%), respectively.

Updated April 15, 2015
Katrina Grantz
 
BOR.jpg
 
We just closed on a house in Boulder City. The local paper ran an article on the lake and the government is going to spend 1.5 million dollars on extending and repairing the various ramps. The local economy needs the business from Lake Mead visitors and there is no way they will allow the access to be totally compromised. Two months ago they put a large cat hoe in the Boulder cut and pulled out a lot of dirt. They will just keep dong that as long as needed.
Bob
 
For those who want to read about the treaties and obligations (?) in the upper and lower Colorado River Basins:

http://www.eenews.net/stories/1060011038

Under a 1922 compact, negotiators parceled out 16.4 million acre-feet between the Upper Basin states, Colorado, Wyoming, Utah and New Mexico; the Lower Basin's Arizona, California and Nevada; and Mexico.

But scientists now say that these calculations were based on an unusually soggy period, and that normal flows are decidedly lower.

The system has been kept afloat by collecting extra runoff from wet years in Lake Mead and Lake Powell, the system's two main reservoirs, and drawing them down until the next big water year came along.

But the current prolonged drought is pushing this approach to its limits, as reservoirs continue to be tapped without replenishment. Today, Lake Powell stands at 48 percent capacity and Mead at 40 percent.

Meanwhile, demand is projected to grow. The Lower Basin states are consuming their full 7.5-million-acre-foot allocation under the compact, but the Upper Basin states are using only about 60 percent of their share. All four Upper Basin states have plans underway to tap more in the future.
Click to expand...

There are also serious legal obligations at play.

Under the 1922 compact, the Upper Basin has to release 75 million acre-feet over 10 years out of Lake Powell to the Lower Basin states and Mexico.

Under this regime, the Upper Basin can afford a dry year or two when it makes lower-than-average deliveries if they are balanced out by wet years when larger deliveries are made.

But multiple years in which less than 7.5 million acre-feet is sent downstream could spell trouble. There are also questions about whether there would be physical limits to the amount of water that could be let out of the dam if water levels dip below the hydropower turbines.

If the Upper Basin's deliveries fall below what's required under the compact, the Interior Department would step in to require states to begin curtailing water use. But what that would look like -- how much from which states, implemented under what rules -- is simply uncharted territory.

"That's the worst-case scenario because we're not ready for it," said Chris Treese with the Colorado River District, Colorado's main water planning agency for the Colorado River Basin. "We're not ready for it to the point that we don't know what would happen."
Click to expand...

Las Vegas, is completing a new 20 foot diameter tunnel, which is even at a much lower level than current intakes. But the politics will enter in if water availability continues to diminish.

One number for those of us who launch at Wahweap is 3583 feet, and that is the minimal level at which the Castle Rock Cut off is usable. This cuts several miles off the trip "up river"--and avoids both several "no wake" zones, and the wash tub effect having to go South from Wahweap and then East, south of Antelope Island, vs the shorter route of going North East and then East up river via Castle Rock Cut:

FIGURE%205.jpg
 
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