We need to consider the future supply of water in plans for growth in Boulder City. Boulder City used over 3 billion gallons of water so far this year (about 550 gallons per person per day). Residential consumption was about 200 gallons per person per day. None of this water is returned to Lake Mead. In the Las Vegas Valley water use is about 100 gallons per person per day because about 50 percent of the water removed from Lake Mead is returned to the lake.
The city is planning to add a few thousand homes to Boulder City over the next decade. If these new subdivisions come with parks and commercial and industrial development, the per capita water demand will probably remain at 550 gallons per person per day but our overall demand will increase.
To build a new subdivision we need to guarantee the water supply for at least 30 years. For say 5,000 homes, 10,000 people, we require 60 billion additional gallons of water over the next 30 years. The buyers of these homes may discover that their homes are only valued at a fraction of the price they paid for them because Lake Mead has run out of water and that this was known to be likely at the time the development was approved. They might sue the city and ask for the several billion dollars they collectively spent to be refunded with interest. Who will insure us against this risk? What is the cost?
How significant is the risk? Boulder City gets its water from the Colorado River. Annual flows of 16.5 million acre-feet are allocated according to the Colorado River Compact. Unfortunately, the Colorado River is out of compliance. The mean natural flows at Lees Ferry, Arizona, have been about 12 million acre-feet per year over the period 2000-2015.
The Colorado River has been breaking the “law” for much longer than that. Tree-ring reconstructions reveal that the natural flows at Lees Ferry over the past 12 centuries have been closer to 14.5 million acre-feet per year. The total Colorado River system storage is now at 45 percent capacity versus 94 percent capacity in 1999. Lake Mead is now at 38 percent of capacity. In the next six months Lake Mead storage is projected to fall by a further 10 percent.
The lake levels are falling because of a mismatch between supply and demand. We cannot indefinitely continue to increase demand while supply falls. The Colorado River is flowing at levels not seen in the historical record of the past thousand years.
Climate change is a reality for us in the desert. We do not know what is going to happen in the next decades. Models suggest that multidecadal droughts will be more frequent but we do not know this for sure. Uncertainty does not mean there is no risk. If the pilot of your flight to Phoenix says he has no idea whether the flight will land safely, passengers should not feel reassured.
Like it or not, this is the situation we find ourselves in as we plan our garden of Eden in the Eldorado Valley. Officials who make the decisions will not be held accountable for their irresponsible stewardship of our city, but the residents certainly will pay the full price.
Objections to the arguments for caution presented above are numerous. 1) We only use a very small fraction of Colorado River water so it doesn’t matter what we do. Answer: If all 40 million users of Colorado River water act this way, Lake Mead will be dry in a few months.
2) We can have growth without increased water consumption. Answer: Which golf course and municipal park shall we shut down first?
3) Climate change is a hoax. Answer: Most scientists with credentials think that it is real. 2016 is the hottest year since thermometer records were kept for our planet.
4) There is a large supply of water in Lincoln and White Pine counties that we can use at will. Answer: This issue is being litigated and has not been resolved. The one ruling made to date stripped the Southern Nevada Water Authority of its water rights for the proposed pipeline.
Boulder City is a fine town. We have a responsibility to hand it to the next generation in at least as good shape as we found it.
George Rhee teaches physics and astronomy at UNLV. He has lived in Boulder City since 1996.
Editor’s note: According to Boulder City’s utility billing and collection supervisor, the city has used 3,662,900 million gallons of water since December 2015, and residential consumption is at 1,072,666 million gallons.