Water 4.0

Envisioning a different tomorrow

Civil and environmental engineering professor David Sedlak’s new book, Water 4.0: The Past, Present and Future of the World’s Most Vital Resource (Yale University Press, 2014), calls for major changes in urban water systems. “If they want to realize the full benefits of conservation, water utilities will have to accept the idea that they are no longer in the business of selling water,” says Sedlak. “Rather, they are stewards of a limited resource.” An excerpt follows.

David SedlakDavid Sedlak (Photo by Daniel McGlynn)Ever since the Romans pioneered Water 1.0, centralization has been the big idea behind urban water systems. In fact, this original design principle has been so potent that each of the subsequent upgrades was built on its foundation. Starting with the addition of filtration and chlorine disinfection on the front end of water distribution systems (Water 2.0), and continuing to the installation of biological wastewater treatment on the sewer end (Water 3.0) and beyond, modern water infrastructure is still guided by its original blueprint of ancient Roman-style aqueducts and sewers.

Centralized urban water systems are presently under considerable stress from a variety of overlapping factors. Increases in population density, changing precipitation patterns, competition for water resources and recognition of the need to leave more water in streams to protect aquatic habitats are driving a movement toward formerly unusable water sources, such as seawater and wastewater effluent, for our next drinking-water supply projects. Coincident with these changes, concerns about chlorine disinfection byproducts, endocrine-disrupting chemicals and pollution of surface waters with nutrients are causing us to rethink our ideas about water and wastewater treatment. And a deeper awareness of the damage caused by storm water runoff is leading to a new focus on urban drainage systems. But coming up with the money needed to expand the water supply portfolio, improve treatment efficiencies, and fix urban drainage systems at the same time that our long-neglected pipe networks and treatment plants are reaching the ends of their design lifetimes is a tall order.

Not surprisingly, most cities appear to be on the path of least resistance, sticking with the centralized systems that have served them so well. In essence, they are doubling down on bets that their existing systems are up to the coming challenges. This approach means that utility managers will do their best to meet growing water demands by expanding imported water systems. When the conventional mode of expansion is no longer possible, they’ll turn to reverse osmosis membranes to convert sewage effluent or seawater into drinking water. To maintain the network of decaying water and sewer pipes and to reduce the frequency of combined sewer overflows, they will dig up the streets and build gigantic underground tunnels to keep excess runoff out of their treatment plants. And to pay for all of these new projects, they will turn to their customers, raising monthly bills at rates that are just low enough to avoid a serious backlash.

I am pretty confident that this approach will work in most places—at least in the short term. Money will keep the water flowing, but it won’t always be pretty. Examples of the coming problems that will be faced are evident in Indianapolis, where homeowners can expect to pay an extra hundred dollars per month to cover the construction of new stormwater-bypass tunnels; in Southern California, where more political fights and rising bills are on the way as plans to expand potable water reuse programs advance; and in Perth, where citizens are absorbing the sticker shock of new desalination plants built to compensate for the effects of climate change on the local precipitation pattern. Painful decisions about urban water systems will be further complicated by uncertainty surrounding the effects of climate change on precipitation patterns and the unlikely prospect of significant new government investments in water infrastructure. In light of all of these factors, there is no way of knowing when the cycle of crises and expenditures will end.

In recognition of the problems associated with our current approach, some people have advocated for something different. They assert that the answer to our water problems can be found in the adoption of practices that reduce the amount of water passing through urban water systems. This belief grew out of the observation that water conservation can forestall the need to develop new water supplies. Conservation also saves energy and helps growing cities avoid costly investments in expanding the capacity of their sewage treatment plants.

The idea of reducing water use as a way of controlling runaway increases in water bills and simultaneously minimizing damage to the environment is intuitively appealing and often results in immediate economic benefits for utilities. Investing in efficiency should be a lot more effective than mindlessly plowing more money into the expansion of existing water systems. Unfortunately, urban water systems and the institutions that support them have evolved in ways that ultimately restrict the ability of conservation and related efficiency measures to solve our most pressing problems.

The first factor that prevents conservation from being a panacea is that water utilities have a limited number of tools they can use to change the behavior of their customers. The tools they do possess—namely, raising the price of water and offering rebates to offset the costs of installing water-saving devices—are often inadequate when it comes to achieving the full potential of conservation. If a utility really wants to reduce water consumption, these approaches will only go so far; serious conservation will require a fundamental change in public attitudes about the value of water and the role that water utilities play in determining how it can be used. Unfortunately, such changes tend to be unpopular with politically powerful constituencies such as real estate developers, libertarians, and members of anti-tax groups, who bristle at the idea of regulations that restrict personal liberties and increase the costs of home ownership.

Talented water utility managers are sometimes able to navigate the political process to bring about the necessary policy changes, especially if there is already an awareness in the community of the consequences of impending water shortages. But water utility managers are rarely at the top of the political hierarchy. When it is time to balance the goals of water conservation against economic development, political philosophy, and the desire of elected officials to please their constituents, these managers often find themselves unable to implement the kinds of changes needed to support their desired water-saving policies. Faced with the uncertainties of the political process, utility managers find it easier to return to more politically safe solutions involving backhoes, pipes, and concrete.

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