Water Conservation - Does It Increase Drought Risk? Not Necessarily
Anil Bamezai, Ph.D., consultant to the Alliance for Water Efficiency, presented last week at the Central Texas Water Conservation Symposium on the Alliance's An Assessment of Increasing Water Use Efficiency on Demand Hardening report. The heart of the report is a review of a worry, that "investments in water‐use efficiency may make it harder for their customers to comply with voluntary or mandatory restrictions when such restrictions are needed to deal with extended periods of shortage."
In other words, if we all become very effective at conserving water (both ourselves and all the people who move in around us), what happens if we have a drought? Could we conserve even more? This concern is periodically expressed (in industry publications as well as conversation) as a caution against over-investment in water conservation, despite conservation's relative cost-effectiveness compared to other water management strategies.
The graph at the top of this post suggests that, as of today, there is no statistical correlation between how water efficient a community is, and how much it can drop its consumption in times of drought. While one needs to ensure consistency in the measurement of gallon per capita per day (GPCD) as a measurement of efficiency, the case studies show that both efficient and inefficient communities can achieve short-term water use reductions of 20 percent or more. Telephone surveys of customers also indicated a willingness to cut back on water consumption in times of crisis.
Changes in water use patterns create a need to be very specific in one's response to drought. In times of drought, the first line of defense is usually to cut back on water use for outdoor irrigation. But if outdoor water use is only a small percentage of overall water use (see Santa Fe as an example, below),
then a drought contingency plan would need to rapidly move to cut indoor water consumption, a more behavior- or capital-intensive effort. The report concludes, "as per‐capita demand falls because of investments in water‐use efficiency, it becomes necessary for suppliers to fast forward to steps that normally would have been taken later in the more traditionally configured shortage plans."
The lesson learned here is that water efficiency, in supporting growing populations with available water resources, does not in and of itself "harden demand." The Alliance's report is worth the read, and addresses nuanced angles without taking a "hard" or inflexible position on whether there may be problems. Water efficiency and conservation are highly cost-effective investments that can defer infrastructure expansions and make more use of limited water and capital resources. However, as communities become more efficient to make use of limited water resources, "one-size-fits-all" drought contingency plans will not serve those communities well.