Herdt: Learning to adapt to droughts

State hydrologists made their annual early-January trek up into the Sierra last week to measure the snowpack and its water content. What they found was that conditions today are tied for the driest on record.

On its own, that finding would be disconcerting enough in this water-deficient state. More unsettling is that the dismal snowpack is a repeat of what was measured just two years ago. In other words, the two driest measurements on record were taken in 2012 and 2014.

The findings were of no surprise, as the measurements took place just three days following the end of a year in which statewide precipitation was the lowest in recorded history.

It was dry all over California in 2013, but some of the rainfall recordings were stunning.

The state has been recording rainfall in Santa Cruz for 120 years, and until last year the lowest measurement, recorded in 1929, had been 11.85 inches. In 2013, less than 5 inches fell. In a normal year, Santa Cruz can expect more than 30 inches of rain.

Given such numbers, it is small wonder that on Tuesday the president of the California Catholic Conference asked that people of faith begin to pray for rain.

Let's begin this paragraph with the requisite disclaimer: No single meteorological event can be attributed to climate change. That said, scientists have been telling us that dry years such as this are in our future.

Consider this assessment included in the environmental impact report on the Bay Delta Conservation Plan, which cites a study headed by Scripps Institution of Oceanography scientist D.R. Cayan: "Cayan et al. (2009) estimates California, particularly Southern California, will be 15 percent to 35 percent drier by 2100. Snowpack volumes are expected to diminish by 25 percent by 2050." And then there is this, from the same document: "California's water supply system is dependent on snowpack storage in the Sierra Nevada. Temperatures in the Sierra Nevada have increased during the last 100 years, resulting in less snowfall (and more rainfall) and an earlier snowmelt. The average early spring snowpack in the Sierra Nevada has decreased by about 10 percent during the last century, a loss of 1.5 million acre-feet of snowpack storage."

It has historically taken periods of drought to create the political conditions necessary to provoke action on water policy. As it happens, this period of lack of precipitation comes at a precipitous time.

The EIR on the Bay Delta Plan and its controversial twin tunnels to divert Sacramento River water beneath the Delta is now circulating and could be certified by the end of this year. Additionally, the state Legislature is seeking to craft a major water bond to place before voters in November.

The drought and the climate change forecasts combine to bring a few imperatives into focus: the Bay Delta Plan must ensure greater reliability of water exports, and the bond must include provisions for additional water storage.

If nature's snowpack storage system is literally going to melt away in March instead of June, at least some of that storage must be replaced by man-made means.

In addition, earlier melts and more precipitation falling as rain instead of snow increase the likelihood of high-flow events in the Sacramento and San Joaquin River watersheds. An improved conveyance system that maximizes the capture of those high flows and minimizes flood-level runoff into the ocean is a necessary step to adapt to the effects of climate change.

As for the bond, voters facing mandated restrictions on water use, might well be in the mood to approve funding for a menu of tools for dealing with drought: Water recycling, groundwater cleanup, above- and below-ground storage, conservation efficiencies and the like.

For both political and environmental reasons, the bond would also need to include hundreds of millions of dollars to pay for projects designed to improve badly degraded Delta ecosystems.

Regardless of whether it is intended to be, any water bond would be viewed by many as a referendum on the Bay Delta Plan and the twin tunnels it envisions. Northern Californians, ever protective of their water resources and ever suspicious of their neighbors to the south, deserve assurance that the portions of the plan designed to protect the Delta will be funded.

Droughts are hardly uncommon in arid California. Once it is officially declared, this one will become the 10th severe, multiyear drought in the last 100 years.

But given the scientific modeling of the effects of climate change, there seems something more ominous about this one. Wet years and dry years come and go, but the effects of atmospheric change are here to stay.

Timm Herdt is a columnist for the Ventura County Star.