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Diversifying San Francisco’s water supply

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Robert Louis Stevenson Elementary School students give tours of their new stormwater garden at the school in the Sunset District on Wednesday, Oct. 10, 2018. (DavÌd RodrÌguez/Special to S.F. Examiner)

Last week, students at Robert Louis Stevenson Elementary School celebrated a more sustainable future. As part of the Stormwater School Yard Project, city officials replaced a portion of playground pavement with green infrastructure.

Now, instead of running off the concrete into drains, rain will seep into the soil through gardens and permeable pavers. The project will remove over 475,000 gallons from the sewage system yearly and recharge groundwater.

“Conservation of water is important because water is essential to life,” Trisha Yee, a fourth-grade student, told the assembled students at the unveiling.

While most San Franciscans try to conserve, pools of water stand as a testament to how the vital resource is often mismanaged. More property owners should shift our unsustainable and dated approach to water.

The San Francisco Public Utilities Commission will provide grants next year and possibly impose fees soon to incentivize additional green infrastructure projects. More owners and residential developers should also install plumbing to reuse relatively clean water, or graywater, from bathroom sinks, showers and laundry machines. These improvements will become more vital as climate change worsens.

“We need to diversify our water supply and we should have started a while ago,” San Francisco Public Utilities Commissioner Francesca Vietor told me.

Currently, the Hetch Hetchy Reservoir in Yosemite National Park provides approximately 85% of the City’s water. The system was designed in the early 20th-century to capture spring snowmelt from the Tuolumne River. Today, extended droughts and overuse by San Francisco and other water districts have reduced flows.

But the water, critical for endangered salmon and other wildlife, still travels over 160 miles to the City. It flows out of our taps and down the drain as we wash our hands and rinse produce. This graywater is combined with other wastewater, including rain that falls on The City’s impermeable surfaces. The SFPUC treats the water and releases it into the San Francisco Bay and Pacific Ocean.

It’s crazy that we let a precious resource literally slip past our fingers. While some new developments, like Salesforce Tower and the renovation of the Moscone Center, are capturing rainwater and installing graywater plumbing, we remain largely dependent on the old system.

“Alternatives are available and feasible,” Spreck Rosekrans, executive director of Save Hetch Hetchy, a nonprofit fighting to restore the area, told me. “It’s San Francisco’s job to implement.”

The City is doing more to break up pavement. The SFPUC plans to offer incentives to create more rain gardens, permeable pavement and other green improvements through a grant program starting next year. In addition, the agency is considering phasing in a stormwater portion of the sewer bill for all San Francisco properties, including credits for green infrastructure, in 2022.

The SFPUC also offers grants to encourage properties to collect, treat and use alternate water sources, including graywater. Projects that can replace 450,000 gallons or more of potable water per year are eligible for grants up to $500,000. Developments of 250,000 square feet or more are required to use onsite water reuse systems for toilet flushing and irrigation per San Francisco law.

But smaller residential developers should install graywater infrastructure too. Most proposed projects in the San Francisco Planning Department’s pipeline report are 50 units or less, and would not likely qualify for graywater grants or need to install systems by mandate.

Jean Gengler, an environmental activist and San Francisco resident since 1974, believes this should change, and is reaching out to leaders and mobilizing support on the site, Nextdoor.

“Individuals in apartments aren’t going to water the grass with a bucket from their shower,” she told me. “I understand people saying there are more important issues and the cost this might add to build in the City, but I think there are costs if we don’t do it.”

Last week, a United Nations report gave the world until 2030 to reduce greenhouse gas emissions significantly or face a climate change catastrophe. San Francisco must take the warning seriously. We must adapt to a future with longer droughts, unpredictable weather and scarcer water.

Hopefully, other property owners will follow Robert Louis Stevenson’s example and celebrate a more sustainable future too.

Robyn Purchia is an environmental attorney, environmental blogger and environmental activist who hikes, gardens and tree hugs in her spare time. Check her out at robynpurchia.com.

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