The Bulletin of Atomic Scientists of Feb. 16 featured an interview by journalist Dan Drollette Jr. of Peter Gleick, recipient of a MacArthur “genius” fellowship and founder of the Pacific Institute, on the water crisis in Cape Town, South Africa. Gleick explained that for the first time a major city is on the verge of literally turning off its municipal water supply system because of a lack of water. Whether or not it actually happens will depend on whether they’re able to implement programs that reduce enough demand and whether it starts to rain.
Although there are still enormous disparities, South Africa has been a world leader since apartheid ended in addressing previously unmet needs for water and sanitation. The problem is a combination of population growth and absolute limits on new supply. They’re running into peak water constraints and the new reality of climate change.
Previously, water planners and managers had assumed that the climate was variable but stable, that there would be wet years and dry years but that it wouldn’t be changing over time in the long run. That’s no longer true.
We know that humans are causing climate change and we know that some of the worst impacts will be manifested in changes in the hydrologic cycle and changes in water availability and demand. Cape Town is at the limits of getting any new supply. Cape Town is over-tapping its rivers and over-pumping groundwater. The population continues to grow and demands for water continue to grow. Higher temperatures worsen the severity of the drought by increasing the demand for water and the loss of water from soils and reservoirs.
Even though water is a renewable resource, there are limits to how much we can take and use. When the entire flow of rivers, such as the Colorado or Yangtze or Yellow, has been taken a peak constraint occurs. In addition, as much as a third of all the groundwater that’s pumped worldwide now comes from non-renewable groundwater resources. That’s a peak limit as well. More and more regions of the world are reaching peak water. Pumping from ever deeper and deeper levels becomes economically infeasible.
The Ogallala Aquifer is a good example of a peak limit. It is a fossil aquifer that underlies Texas, Oklahoma, Nebraska, Kansas and several other states. It was laid down over tens of thousands of years, but it is being pumped out in decades. Other examples of peak limits are happening in the Middle East, Northern China, parts of Indian and in parts of the Central Valley of California.
Fortunately, the United States has the economic and technical ability to shift water from one user to another, to implement conservation programs that reduce demand–to do the things that Cape Town is doing now–but to do them more effectively. Places like Jakarta or Tehran, or places in the developing world where they don’t have alternatives, where they don’t have the economic ability to use treated wastewater or to desalinate water, and where they don’t have the management ability to implement smart and effective conservation programs are more threatened.
In the 1980s, engineers in Boston plugged a lot of leaks and upgraded all the pipes in the city’s water supply system and reduced water consumption by 40 percent. The cheapest source of new water is not actually new water – it’s spending money on conservation and efficiency programs that let us save water we’re already using.
The smartest thing we can do is make our water use more efficient, to grow more food with less water, to flush our toilets and wash our clothes with less water, to keep the benefits of our water use while reducing the volume of water required to satisfy those benefits.
In the fourth of five years of the California drought, the state imposed a mandatory reduction in urban water use of 25 percent. This was accomplished through a mix of programs. People were offered money to remove lawns and replace them with “xeriscaped” or drought-resistant gardens. Utilities offered rebates on efficient toilets and washing machines. There were restrictions on the timing and the amount of outdoor landscaping. There were changes in rate structures that encouraged people to save money by saving water. Penalties were imposed on high water users.
In the long run, we’re moving toward a sustainable future for water or the soft path for water. It involves alternative sources of supply, like using treated wastewater and capturing more storm water; improving the way we use water and becoming more efficient; smart economic policies and better management. It involves accepting the reality of climate change and integrating the risks of climate change into the way we plan and manage our water systems.
This article first appeared in the March 14, 2018 issue of the Rossmoor News. Author Judith Schumacher-Jennings can be emailed at email@example.com.