Diminishing Returns to Dam Building and Other Supply Solutions

Megadam Projects not Successful” highlights what many in Texas and elsewhere will see as an inconvenient, but critical, truth: there are diminishing returns to structural solutions to water scarcity problems. One reason that it is inconvenient is that there is a lot of money in dam building, and another is that water planners and municipal purveyors are not used to the demand-side approaches to make sure that demand will not exceed supply even in a worst-case-scenario drought.

Sole reliance on supply-side solutions to meet that mandate means the environmentally and fiscally costly construction of some projects that will sit idle most of the time. There are two alternatives that become more and more economically efficient as additional water supply projects come on line:

  • Provision for permanent and temporary market-based re-allocations of existing water rights, which means true private ownership of water consumption rights. Water price differences, or lacking those, water use value differences, will signal which way true markets would move water. It would not be a mass-movement because the prices are changed by the re-allocations, sometimes significantly by small reductions in sellers’ water use. For example, a relatively small re-allocation of irrigation water can slightly increase the value of agricultural water while massively decreasing the cost of municipal water.
  • For water supplies like municipal utilities and irrigation companies, provision of some discounted interruptible service. The option to buy a mix of non-interruptible and discounted interruptible service has been long-time standard fare in industries like natural gas that are much less vulnerable to the double whammy of simultaneous increase in demand and decrease in supply that comes with drought.

But gas providers and users are spending their own money, whereas government-run water purveyors spend someone else’s money. So, as water projects come online it eventually becomes cheaper to provide discounts for service that is interrupted in specified drought conditions than to have a nearly-always idle water project on standby for a rare situation.

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