A Tale of Two Lakes
by CRAIG JAMES
This is a tale of two lakes, not two cities. The first lake is Devil’s Lake in North Dakota. Since 1940, this lake has risen nearly 50 feet! It has risen almost 29 feet just since 1993, but it is still not quite as high as it has been in the past, as seen on this graph from the North Dakota State Water Commission, showing water levels over the past 4,000 years.
The lake experiences what appear to be normal fluctuations from dry to overflowing, which have little to do with global warming. Since the lake has no natural outlet, excess snow melt and rainfall remain in the lake until it rises another seven feet, where it can then discharge into the nearest river. The last time it spilled into the river was a little less than 2,000 years ago.
Since the 1940s of course, communities have built up along the lakeshore, not taking into consideration the past history of the lake. These communities are now being flooded and over 10% of the population has moved out of the area. Over 400 homes have been moved or destroyed and not without considerable cost.
By the end of 2010, the federal government will have spent more than $1 billion to ease the threat, buying flooded property, building dikes and making other improvements. That figure does not include a $27 million floodwater-diversion channel built by the state on the west end of the lake. It also costs $330,000 a month for the electricity for pumps to take one inch off the lake. Those are all our tax dollars spent so people could live on a lake that history has shown has always fluctuated this much.
The other lake is Lake Mead in Nevada. This lake is experiencing the opposite problem: water levels are falling. The lake has dropped an amazing 126 feet since 1985, at one point losing 60 feet in just three years! The graph shows the fluctuations in the water level since the lake was filled behind Hoover Dam in 1937.
The lake receives 96% of its water from snowmelt that drains into the Colorado River basin. During the past decade of drought conditions, the amount of water leaving the lake for irrigation and other purposes to serve a rapidly increasing population has exceeded the amount of water flowing into the lake. This has also happened two other times in the past. After the drought in the mid ‘50s, the lake took only one year to recover, but after the drought in the mid ‘60s and the filling of another upstream reservoir, Lake Powell, the lake took 10 years to recover.
Marinas everywhere around the lake’s edge have had to migrate down the shoreline. It is estimated that each 20 feet in water-level change costs the National Park Service around $6 million. A 20-foot vertical drop results in approximately a 600-foot move in the shoreline in some areas. Rangers are rediscovering roads and boat ramps built during the severe dry spell in the mid-1960s when the water levels were last this low. In the 40 years since, the locations of these features were forgotten after they were submerged.
No one can reliably forecast when this drought will end, but with the continued population increase, it may take even longer to recover than the last time. Since the Las Vegas area receives about 90% of its water from Lake Mead, officials are understandably worried. The Southern Nevada Water Authority will vote soon on whether to construct a multi-billion-dollar pipeline to tap groundwater from eastern Nevada. This is on top of a $700 million project being rushed to completion that will draw water from deeper in Lake Mead than currently possible.
If the behavior of these two lakes is a surprise to anyone, it shouldn’t be, the historical record clearly shows the cyclical nature of… well, nature. It’s the same with climate (and you wondered how I was going to work that in).
Craig James has been retired since July 1, 2008, after 40 years of broadcasting television weather. He was chief meteorologist at WZZM-TV for 12 years and chief meteorologist at WOOD-TV for 24 years. He is a graduate of Penn State University, where he received a Centennial Fellowship Award. He was also honored as a Fellow of the American Meteorological Society.