During my brief tenure at the Press Democrat over in Santa Rosa, I got to indulge two of my longtime passions – weather and the complicated state of our civil infrastructure.
I was covering the early stirrings of our current drought, and one of the first interesting things I discovered was that there is no technical definition of a drought, at least in the sense of an equation: If A happens, then B happens, then we are in a drought. Rather it is more of a general condition. Loosely speaking, a “drought” is any time your water supply is impaired for any significant length of time.
That’s why you can have a long dry spell that is not a drought. Likewise, you can have a long wet spell, as we have been having this past week, and still be firmly in a drought.
In that sense, a “drought” is a little hard to define, but you know it when you see it. And because the indicators are so varied and hard to interpret, a drought is somewhat like an economic downtown – you often don’t know you’re in one until it is well underway and it is often only in retrospect that you can determine when it ended.
One thing we can tell is that the drought is not over yet. Despite some refreshingly damp weather in January and in the first few weeks of March, about 60 percent of California is in an “extreme drought,” according to the USDA drought monitoring service. More than half of that total is in “exceptional drought,” by some estimates the worst drought in more than 1,200 years.
That is a slight improvement over last year, where more than 67 percent was in extreme drought, two-thirds of which was in exceptional drought.
Over the last year, most of Napa County has dropped out of the extreme drought area, but the whole county remains in a severe drought condition, despite recent rains.
How can this be, since our reservoirs are nearly full and our hills are green?
The answer goes back to another thing I discovered while at the Press Democrat: how complicated and interwoven California’s water system is.
Although we have decent reservoir capacity in most of our cities (American Canyon being the glaring exception), and although we appear to have robust groundwater supplies, at least on the valley floor, most of Napa County’s residents are dependent on the state water system to meet their daily needs.
The city of Napa, for example, has several years worth of water stored in Lake Hennessey, but it lacks the pipeline and treatment capacity to supply the whole city regularly in the summer exclusively from that source. That means it has to buy water from the state system. Calistoga has a reservoir, but that only supplies about half of the city’s routine needs; the rest comes from the state.
American Canyon, which has no reservoir of its own, is at the mercy of the state system.
As of Thursday morning, many of the key reservoirs in the state were well below their historical averages for this time of year. Lake Shasta, for example, was at 69 percent of capacity, which sounds good unless you know that’s only about 91 percent of what’s usually in the lake on that date. Even worse, Trinity Lake is just 41 percent full, slightly better than half what it should be this time of year.
Meanwhile, the reservoirs that are at or above normal are actually going backwards slightly, since they have had to dump water to preserve space for flood control. This seems counter-intuitive in a drought, but if the reservoirs fill to the brim and then we have an unusually wet spring, it could unleash devastating flooding downstream or even threaten the structural integrity of the dams.
Water engineers and scientists are working on ways to better understand rainfall patterns, runoff, and flooding in California so we don’t waste so much water on flood control, but it was clear from my reporting at the Press Democrat that we are still years away from the kind of precision weather forecasting that would be necessary to risk allowing reservoirs to fill completely in the rainy season.
Worse, the state’s snow pack, which provides about half the water Californians need every year, is only about 84 percent of its normal water content for this time of year. That’s an astronomical improvement over last year, when the snowpack was effectively gone. But given the depleted state of the reservoirs and ground water reserves, the snowpack would have to be well above normal – perhaps as much as 150 percent of normal – going into the spring for officials to declare an end of the drought.
We here at the Register have gotten a number of letters and online comments gleefully declaring the end of the drought; some have even declared this a “phony drought.”
It is certainly true that Napa County is far better off than most of the state, but we are still closely tied to and dependent on the state water system. To say there is no drought in Napa County just because we have water is the equivalent of saying that just because we have some cash in our wallets, we are not in debt, or because we have food on the table, there is no such thing as hunger.
The rain we are experiencing is a welcome relief and will stave off the catastrophic possibilities that loomed had the dry spell continued. The trend lines are certainly pointing in the right direction for an end to the drought, but until conditions return to normal across most of the state, we here in Napa County – and all Californians – remain in a drought that we need to take seriously.