Study: In Drought Planning, Water Managers Should Look Further Back Than 1950s
As we near the end of 2011, let us now look back on the year (without much fondness) and take stock. We racked up one of driest years in recorded history (more on that in a moment). The livestock and agricultural industries took a shuddering blow that, when the final accounting comes, might just break into the double-digit billions of dollars. Texas's herd declined at a rate not seen since the 30s. And, by all accounts, the drought isn't over yet.
About that "driest year in recorded history." Turns out, as we head into another arid year, and probably another after that, everyone -- especially water managers -- would do well to look a little deeper into the past. For Texas, the seven-year drought of the 1950s is the touchstone by which we compare all others. But it isn't much more than a wink in the eons. According to a new study using the trunks of long-lived trees to gauge precipitation in centuries past, it ain't the worst Mother Nature can dish out. And as anthropogenic climate change pushes weather to extremes, it's bound to get bad. Factor in a state whose population growth shows no sign of slowing, and you get a recipe for water crisis.
"This and previous studies indicate that severe decadal-scale droughts have occurred in Texas at least once a century since the 1500s. Current use by water planners of the 1950s drought as a worst-case scenario, therefore, is questionable," the Texas Water Journal says. "When water managers consider past droughts, population growth, and climate change, it becomes highly probable that the future poses unprecedented challenges."
They identified 30-year droughts in the 1500s, 1700s and mid-1800s, which is, coincidentally, about as far back as conventional meteorological observations go.
"The recurrence of severe prolonged drought in South Central Texas appears to be the norm," the study concludes, "not the exception."