Drought Compounded by Population Growth

Two articles today highlight the contribution population growth has made in amplifying the drought in the southeastern United States from inconvenience to crisis. First up, the indispensable Peter Gleik from the Pacific Institute:

The amount of water in a river basin or watershed is fixed. It goes up and down with natural variability, and it may change over time due to climate changes, but water is a renewable resources and our use of it does not affect the amount we get next year.

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In a recent paper, Richard Seager of Columbia and his colleagues analyzed the recent drought in the southeastern United States. This drought led to water use restrictions, depleted flows in the major river basins of the region, and growing political tensions over water sharing between Georgia, Alabama, and Florida. The authors of this paper concluded that the recent drought in the Southeast was not climatologically different from past droughts, but was felt more severely largely due to the growth in population in the region.

The Christian Science Monitor adds to the story:

Was the drought, which also seemed to extend laterally to the Southwest, the result of human-induced climate change?

A new Columbia University study concludes that, in this case, climate change wasn’t to blame. In fact, historically speaking, the drought wasn’t even among the worst of the dry spells that periodically grip the region — the most recent in 1998-2002.

Rather, water shortages in the region — at the height of the drought, Atlanta’s main reservoir dropped by over 14 feet — stemmed directly from increased demand on water. And the surging demand was driven by the rapid population growth of recent decades.

An article on Columbia University’s Earth Institute website paints the picture by numbers:

In 1990, Georgia, which uses a quarter of the region’s water, had 6.5 million people. By 2007, there were 9.5 million — up almost 50 percent in 17 years. The population is still ascending, driven largely by migration. However, little has been done to increase water storage or reduce consumption. There has been increased sewage discharge near water supplies, and vast tracts of land have been covered with impermeable roofs, roads and parking lots, which drain rainfall away rapidly instead of storing it.

So, what to do? Obviously we can't arbitrarily limit a region's growth, which leaves us to choose between massive infrastructure upgrades like new dams and all the economic and environmental costs associated with them, and increased efficiency measures to reduce water use per household and business. But is efficiency alone enough? According to the conservation organization American Rivers, it just might be.

In a report titled “Hidden Reservoir: Why Water Efficiency is the Best Solution for the Southeast,” it argues that “19th century approaches,” such as building more dams and creating more reservoirs, are not adequate to 21st-century challenges. They’re up to 8,500 times more expensive than simple “efficiency investments.”

They list nine measures which, taken together have already proven effective in other regions. Number five on the list?

Landscape to minimize water waste. 58% of urban water use is devoted to our lawns — spiking to as much as 80% in the hottest summer months — and studies have shown that 50%
of outdoor water is wasted – lost to the watering of driveways and sidewalks, evaporation, or
over-watering. Implementing smart irrigation practices including smart irrigation controllers can eliminate much of this waste.

So what's the payoff for implementing efficiency measures?

– Cary, N.C., increased water supply by 11 percent with efficiency measures alone.
– Tampa, Fla., has grown its per capita water supply by 26 percent with efficiency measures.
– Boston succeeded in reducing its overall water consumption by one-third while increasing its customer base by 2 million people. The result? Not needing to build a proposed dam saved the city $500 million.

The bottom line: municipalities and states can continue to grow and prosper within their current water supplies and without investing billions in costly and environmentally questionable projects by simply promoting and enforcing basic efficiency standards.