Would more dams help with all this water?
Sometimes, you must pick your crisis. No, we’re not in danger of massive flooding, not yet.
New Melones is only half full, so no worries along the Stanislaus. But the water flowing into Don Pedro and McClure reservoirs deserves a careful eye.
Monday’s outflow from Don Pedro on the Tuolumne River was 9,800 cubic feet per second (a cubic foot is a basketball-size drop of water), or about 800 cfs higher than normal maximum flows. Because Don Pedro was 98 percent full, and more rain and runoff are expected this week, authorities have authorized river flows up to 11,000 cfs.
Already, there’s been flooding in low-lying areas along the San Joaquin River in western Stanislaus County. A few living in camps along its banks near the confluence of the Tuolumne have lost their mobile homes, and the Turlock Sportsman’s Club and Old Fisherman’s Club will have to dry out – just as they have many times in the past.
On the Merced River, Lake McClure was at 91 percent – or around 930,000 acre-feet. There’s still room behind Exchequer Dam, but it’s filling.
Farmers should take heart in all this water, except for two things:
First, some reservoirs are perilously close to full. The only thing worse than not having enough water is having so much that it tops the dams.
Second, no matter how much water is stored, people here know the state intends to take twice or three times as much as they have in the past. And that means even if we exit this winter with brimming reservoirs, far less of that water will ever be used to grow food that people – rich and poor, near and far – depend on.
Our issues pale in comparison to those around Oroville, where the dam’s spillway has dissolved along with much of the earth around it. There’s more water in the reservoir than ever, and the emergency basin – used for the first time – appears to be eroding. Some 190,000 people have been evacuated.
We hope there’s no catastrophe, but we know this situation will lead to a lot of second-guessing. Whatever happens, much will be written off to uncontrollable and unpredictable nature.
While nature can never be fully controlled, what we’re seeing was predicted.
Scientists have been telling us for a generation that our storms will get bigger and warmer. Just like this one. That means less water will fall as snow and more as rain. Just as it has the past two weeks.
That means our model for “storing” water no longer works. Instead of a time-released reservoir made entirely of mountain snow, we’re getting more frequent storms dropping lots of rain all at once.
Shouldn’t we have already built more reservoirs to capture some of that rain for the dry years? Would a few more dams serve as a check on these massive flows?
More specifically, would the state have allowed Lake Oroville to fill so high if there had been other options – like Sites Reservoir northwest of Sacramento? Voters passed Proposition 1 in 2014, with Sites identified as the most likely reservoir to be built. A full Sites could have meant allowing more water to flow out of Oroville before the spillway failed.
That’s all conjecture. But here’s a fact: If there were no dams, our region would be knee-deep in water today. Our dams have provided both protection from floods and water to grow food. Californians have benefited from both purposes for generations.
Yes, there can be danger in building dams, as the good people who live downstream of Oroville know. But there is greater danger in not building dams – as anyone who lives in the San Joaquin Valley already knows.
This story was originally published February 14, 2017 at 8:41 AM with the headline "Would more dams help with all this water?."