Lake Mead Falls to Record Low

Lake Mead falls to 36 percent of capacity

Lake Mead water level fell to a record low of 327.65m (1,074.98 feet) above sea level, or 36 percent of the available capacity,  just before midnight Tuesday, said the U.S. Bureau of Reclamation.

The level rose slightly to 327.68m (1,075.05 feet), barely above the critical level of 327.66m (1075 feet) by 7 am Wednesday, said the Bureau.

At 327.66m (1075 feet) elevation, Lake Mead has an available capacity of 11.84 km³ (9,601,000 acre feet), with the total available capacity being 32.56 km³ (26,399,000 acre feet), according to the USBR 2009 data.

In August 2010, Lake Mead level fell to 331 meters (1,087 feet) above sea level, compared with August 1985 level of 370m.

Summary of Lake Mead Stats

• Lake Mead is the largest reservoir in the U.S. in terms of water capacity.
• It’s formed by the Hoover Dam (construction finished in 1936), fed by the Colorado River, and located in the states of Nevada and Arizona.
• The lake is 177 km long when full, and has 1,220km of shoreline.
• Max. Width: 12.87km
• Max. Depth: 162m (532 feet)
• The high-water line: 375 m of (1,229 feet) above sea level. ( At this elevation, the water would be more than 7 1/2 feet over the top of the raised spillway gates, which are at elevation 372.28m, or 1,221.4 feet —USBR).
• Surface area: 642 km² (248 square miles) at 372.28m (1,221.4 feet)
• Capacity: 35.7 km³ (28,945,000 acre feet) – less the accumulated sediments.
  • Available capacity: 32.56 km³ (26,399,000 acre feet)
• Last time at full capacity: 1983 (the lake has since been plagued by drought and increased water demand.)
• Current capacity: 36 percent of the available capacity.
• Demand: About 42 million people including farmers in Arizona, California, Nevada and Mexico depend on Leak mead for their water.
  • Lake Mead attracts more than 9 million visitors each year for swimming, boating, skiing, fishing and other outdoor pursuits.
• Annual Inflow: Lake Mead receives most of its water from snow melt in the Colorado, Wyoming, and Utah Rocky Mountains.
• Annual Outflow: About 9.7 million acre feet (12.0 km³)
  • Evaporation (included in the above): About 800,000 acre feet/ year (0.987 km³).
• Annual Deficit: 1.2 million acre feet (1.5 km³)
• Drought: Colorado River is currently experiencing its 15th consecutive year of drought.

Meanwhile, the Bureau of Reclamation has issued the following warning.

Excessive Heat Warning: Visitors to Hoover Dam should expect temperatures at least 10 degrees higher than the Las Vegas area, ranging from [49 to 52 degrees Celsius] 120 to 125 degrees Fahrenheit. There is limited shade at Hoover Dam. Visitors must be prepared for the heat with appropriate clothing and extra water, and are encouraged to visit Hoover Dam during morning hours.

Related Links

• Lake Mead at Lowest Level Ever September 23, 2010

Fish Mass Die-off Near Galveston, Texas

Large fish kill off Galveston blamed on neurotoxic algal bloom

As many as a million dead Gulf menhaden that littered Galveston’s West End beaches on the weekend are believed to have been killed by an algal bloom known as Karenia brevis.

Texas Parks and Wildlife Dept (TPWD) said it had received reports of fish kills from Sea Rim State Park, Sargent Beach and Surfsidehas, and confirmed a bloom of Karenia brevis, also known as red tide, in Galveston Bay.

Karenia brevis. Photo:  FFWCC

Current Status

August 13, 2012 – afternoon

TPWD began receiving reports of fish kills on Friday, August 10. The reports were from Quintana Beach to the mouth of the Colorado River and included mostly Gulf menhaden with a few mentions of gafftopsail and hardhead catfish. Additional fish kills were reported over the weekend at Surfside Beach and Galveston; samples were collected from the Surfside jetty and San Luis Pass to look for Karenia brevis. Dead flounder and stingrays have been reported at Kemah and Bacliff; biologists originally thought that low oxygen levels were to blame, but additional investigations will be conducted to determine if K. brevis is the cause. In addition, fishermen reported coughing and dead fish 4 miles offshore of Galveston.

Related Links

• U.S. Disaster Impact Leaps 24 Folds Posted August 1, 2012
• WARNING: Human impact 2.85 x Earth’s diminishing carrying capacity
• WARNING: RAPID DECLINE IN PROGRESS!

Global Disasters: Links, Forecasts and Background

• The First Wave of World’s Collapsing Cities
• Back to the Primordial Future
• The Fate of Energy Dinosaurs
• Mass Die-offs

• 2010 Disasters [Links to 2010 Disaster Calendar]
• Mega Disasters
• 2011 Disaster Calendar
• 2012 Disaster Calendar

Surprise! World’s largest rivers drying UP!

Climate change drying up world’s 925 largest ocean-reaching rivers

About 72 percent of the world’s 925 largest ocean-reaching rivers are drying up, most of them because of the climate change, according to a report by National Center for Atmospheric Research, Boulder, Colorado.

The Horseshoe Bend of the ‘sewage-green’ Colorado River located near the city of Page, Arizona (dated April 13, 2008). Photo:  Christian Mehlführer, User:Chmehl. Licensed under Creative Commons Attribution 2.5 license.

The largest rivers affected include the Colorado in the United States, the Yellow River in China, the Ganges in India and the Niger in West Africa.

Lower water levels combined with the impact of exponentially growing demands on water for damming, irrigation and other uses could pose a threat to future supplies water and food globally, the researchers said in the American Meteorological Society’s Journal of Climate.

Highlights of the report:

Rivers in some of the world’s most populated regions are losing water, many because of climate change, researchers reported on Tuesday.

• Some 925 largest ocean-reaching rivers are drying up,mostly because of climate change

• The largest affected rivers include the Colorado in the southwestern United States, the Yellow River in northern China, the Ganges in India and the Niger in West Africa.

• “About one-third of the top 200 rivers (including the Congo, Mississippi, Yenisey, Paraná, Ganges, Columbia, Uruguay, and Niger) show statistically significant trends during 1948–2004, with the rivers having downward trends (45) out-numbering those with upward trends (19).”

• Reduced water levels due to climate change combined with the impact of exponentially growing demands on water for damming, irrigation and other uses could pose a threat to future supplies of water and food globally, the researchers said in the American Meteorological Society’s Journal of Climate.

• “Reduced runoff is increasing the pressure on freshwater resources in much of the world, especially with more demand for water as population increases … Freshwater being a vital resource, the downward trends are a great concern.” Said the report’s lead author.

• About one-third of the top 200 rivers  show significant changes during 1948–2004, some 45 rivers showing downward trends, while only 19 show upward trends.

• Annual freshwater discharge into the world’s oceans decreased during the 1948–2004 research period as follows

• Pacific Ocean: down by about 6 percent, or 526 km³

• Indian Ocean: down by about 3 percent, or 140 km³

• In the case of Arctic Ocean annual discharge (from melting ice) rose about 10 percent, or 460 km³

• The Columbia River in the northwestern U.S. lost about 14 percent of its streamflow during the 54-year period because of reduced precipitation and higher water demands, while the Mississippi River flow rose by 22 percent because of increased precipitation in the U.S. Midwest.

• “[T]here is evidence that the rapid warming since the 1970s has caused an earlier onset of spring that induces earlier snowmelt and associated peak streamflow in the western United States and New England and earlier breakup of river-ice in Russian Arctic rivers and many Canadian rivers.”

The following is a free abstract. Full report is sold online at the American Meteorological Society website.

Changes in Continental Freshwater Discharge from 1948–2004

A new data set of historical monthly streamflow at the farthest downstream stations for world’s 925 largest ocean-reaching rivers has been created for community use. Available new gauge records are added to a network of gauges that covers ~80 × 10⁶ km² or ~80% of global ocean-draining land areas and accounts for about 73% of global total runoff. For most of the large rivers, the record for 1948–2004 is fairly complete. Data gaps in the records are filled through linear regression using streamflow simulated by a land surface model (CLM3) forced with observed precipitation and other atmospheric forcings that is significantly (and often strongly) correlated with the observed streamflow for most rivers. Compared with previous studies, the new data set has improved homogeneity and enables more reliable assessments of decadal and long-term changes in continental freshwater discharge into the oceans. The model-simulated runoff ratio over drainage areas with and without gauge records is used to estimate the contribution from the areas not monitored by the gauges in deriving the total discharge into the global oceans.

Results reveal large variations in yearly streamflow for most of world’s large rivers and for continental discharge, but only about one-third of the top 200 rivers (including the Congo, Mississippi, Yenisey, Paraná, Ganges, Columbia, Uruguay, and Niger) show statistically significant trends during 1948–2004, with the rivers having downward trends (45) out-numbering those with upward trends (19). The interannual variations are correlated with the El Niño-Southern Oscillation (ENSO) events for discharge into the Atlantic, Pacific, Indian, and global ocean as a whole. For ocean basins other than the Arctic, and for the global ocean as a whole, the discharge data show small or downward trends, which are statistically significant for the Pacific (−10.1 km³ yr⁻¹) and Indian Ocean (−5.4 km³ yr⁻¹). Precipitation is a major driver for the discharge trends and large interannual to decadal variations. Comparisons with the CLM3 simulation suggest that direct human influence on annual streamflow is likely small compared with climatic forcing during 1948–2004 for most of world’s major rivers. For the Arctic drainage areas, upward trends in streamflow are not accompanied by increasing precipitation, especially over Siberia, based on available data, although recent surface warming and associated downward trends in snow cover and soil-ice content over the northern high-latitudes contribute to increased runoff in these regions. Our results are qualitatively consistent with climate model projections, but contradict an earlier report of increasing continental runoff during the recent decades based on limited records. ( Copyrighted material.)