Hetch Hetchy levels a major concern for water officials
The images and message from the April snow survey were alarming. The snowpack was at a record low, and one of the major Bay Area reservoirs is feeling the impact.
Hetch Hetchy collects melting snowpack and taps into gravity to send water from Yosemite -- 165 miles to our faucets -- to the Bay Area.
85 percent of the region's supply comes from the Sierra, serving San Francisco, most of San Mateo and parts of Alameda and Santa Clara counties. Over 2 million people rely on this water source.
While park visitors walk on the dam, KTVU'S Mark Tamayo hopped on a boat to see how the extreme drought was impacting Hetch Hetchy. One might think a reservoir that relies on snow would be empty. But the reservoir was actually quite full.
SFPUC's Assistant General Manager For Water Steve Ritchie says that even though the reservoir is 70 percent full, there should be a lot more.
We're floating on about 80 billion gallons of water right now, explained Ritchie. As far as the water goes, we'll go up here a little ways, [we] won't see any snow up in the peaks.
Bob Slater has been a watershed keeper at Hetch Hetchy for nine years, seeing both the highs and lows.
On a good water year, that waterfall almost directly into the reservoir, said Slater. When it's running hard and the lake is full, you don't even see these rocks
Wapama Falls is flowing at 2,300 gallons per second. But during a normal year, it would be five times that rate
As the ride continues, more evidence of the drought becomes visible. Dark areas on granite where falls should be flowing are dry, rock structures that should be submerged are above water and the defined boundary of the high water mark.
We reach an area seen by few; the connection between a river and reservoir.
This cup of water will take about 3 days to make it to the Bay Area. Nearby, the Tuolumne River provides the main source of snowmelt for Hetch Hetchy. On an average year they'll fill up the reservoir three times.
This year it won't happen once.
The remaining snow is melting and adding to the supply. By June, reservoir storage will crest at 80 percent of capacity.
It sounds like a lot, but we're actually still borrowing from history. The current supply includes water from the past couple of winters.
"Based off the 1987 through 1992 drought, we started planning as if we might have 8 and half years of drought," explained Ritchie. "You know a series of dry years that we might have to live through and so we're using that planning that we have done in the past to help us manage through what is the reality of this drought."
Hetch Hetchy is just one piece of the puzzle. The entire system supplying the Bay Area -- which includes five more reservoirs and a water reserve -- is only at 54 percent of capacity.
Hoping for a productive winter is not enough. The planning is happening now and that could include more cuts.
"If we have next year as bad as this year, I'm sure we will go to mandatory rationing. Because we'll be in a more severe condition and we will have to assume that it's going to get worst, Slater said.
The falls will soon dry up and the river just a trickle, leaving this reservoir in a vulnerable place. Each turn of the faucet in the bay area will determine what it will look like next year if the drought continues,