WaterSan Francisco to add local groundwater to reservoir supply
The San Francisco Public Utilities Commission has begun digging in the area around Golden Gate Park with the intention of adding local underground water flows to the traditionally sourced water from the Hetch Hetchy Reservoir in Yosemite. The change is expected to take place over the next two years and will replace between 10 to 15 percent of the water supply. Despite the fact that the water is less pure, city officials expect that difference will be negligible.
The San Francisco Public Utilities Commission has begun digging in the area around Golden Gate Park with the intention of adding local underground water flows to the traditionally sourced water from the Hetch Hetchy Reservoir in Yosemite.
TheSan Francisco Chronicle reports that the change is expected to take place over the next two years and will replace between 10 to 15 percent of the water supply. Despite the fact that the water is less pure, city officials expect that difference will be negligible.
“We don’t think people will notice a difference with what they’re drinking,” said Jeff Gilman, the project manager for the plan under the Commission, “It tastes the same. Color is the same. Odor is the same.”
His conviction has also been proven in taste tests. The agency held nine blind taste trials and there was only a slight preference for the more pure Hetch Hetchy water. Twenty percent of those tested also expressed no preference at all. Jon Bonne, a noted wine critic was also brought in to try the water. While he found a “mineral presence” in the blended water, he did not criticize the taste.
Part of the change stems from the fact that the Commission found nitrate levels that exceeded the state standard last year. This is expected to come from fertilizers and leaking pipes as the water is pumped from the reservoir. Blending is often a method of combating the nitrate levels. Fluoride will also be added.
“You might not be able to drink it straight, but blended we’re fine,” said Gilman.
The move is also being as a way to leverage limited supply of water from the reservoir. The blended water will be distributed to about 60 percent of the city, with plans for greater distribution in the event of a drought.
“The city is thinking ahead to when climate change starts to be an issue and about natural hazards like earthquakes,” said David Sedlak, an environmental engineering professor at UC Berkeley and the co-director of the Berkeley Water Center, “Having this local water supply is a really good thing.”
Already, many water agencies across California incorporate the blending method, with about 80 percent of all Californians using blended water for at least some of their daily needs.
The new water is expected to be incorporated into the city by late 2015 or 2016. Four new municipal wells will be added to the two already in existence to draw the reserves.
