By Année Tousseau
Last week, volunteers from Sustainable Silicon Valley (SSV) attended the annual Water Conservation Showcase. The event is a partnership between the US Green Building Council Northern California Chapter, PG&E, East Bay Municipal Utility District, San Francisco Public Utilities Commission, and AIA San Francisco. PG&E provided a venue for the event at its Pacific Energy Center in downtown San Francisco.
The showcase offered an excellent opportunity to meet leaders in the water conservation field, learn about new tech and hardware, discuss major water challenges in California, and hear water conservation success stories. Here are four takeaways from the event.
Technology and hardware upgrades can yield substantial water savings.
Behavioral changes are important, but a session highlighting the water conservation achievements at various University of California campuses put the spotlight on tech and hardware. For example, UC Davis has been able to keep total water use steady even as their on-campus population has tripled. Much of the savings came from the use of reclaimed water in a cooling tower, which yielded savings of 60 million gallons/year. The switch to reclaimed water required water quality monitoring, an air permit change, and advanced controls.
At UC Santa Cruz, energy manager Patrick Testoni described his philosophy: “You can’t manage what you can’t measure.” He spoke of how the campus’ upgrade to a new water metering system, along with upgrades to toilets and other fixtures, have enabled a 20% reduction in water use. And at UC San Francisco, a $5,000 efficient equipment incentive program encouraged the replacement of many sterilizers. These water guzzlers are used in the campus’ many research laboratories.
We’re still in a drought, despite a rainy winter.
If you’ve been reading the news, you know this, but it bears repeating. The current water year (which began in October) is the wettest on record in California, but the state’s drought declaration remains in place. Why? A big part of the reason involves groundwater.
Underground aquifers have been drawn down to record lows, and may take multiple years of average or above-average rainfall to rebound, according to presenter Peter Brostrom of the California Department of Water Resources. This should concern anyone in California who depends on groundwater—and that includes much of the state.
In 2014, the governor signed the Sustainable Groundwater Management Act, which created a framework to help local water agencies manage groundwater supplies more effectively, with the goal of achieving sustainability in 20 years. This legislation was a big step in the history of groundwater regulation in the state.
Onsite water reuse is becoming more financially attractive.
Peter Haase, principal engineer at Fall Creek Engineering and member of the SSV Water Advisory Council, emphasized this point in a presentation with Amelia Luna, the innovation project manager at Sherwood Design Engineers. (Sherwood’s director of innovation, Josiah Cain, also serves on SSV’s Water Advisory Council.)
A couple of factors are combining to make decentralized water reuse projects more financially feasible. The overall cost of water is rising, due to increased scarcity and the fact that much of our water infrastructure was subsidized by the government in the 1970s and decades prior. Since then, California’s population has increased, and much of that infrastructure is reaching the end of its design life. The necessary repairs are costly. These factors favor more decentralized water reuse projects — such as those that treat and reuse wastewater on site for irrigation, toilet flushing, and similar purposes.
“Irrigation is math.”
Presenter Christine Hawkins of Hunter Industries offered this comment at the beginning of her workshop on irrigation with Tom Bressan of The Urban Farmer Store. It was an apt description, especially for those of us not in the landscape design/management industry. As it turns out, the answers to some deceptively simple irrigation questions — How much do I water my plants? How can I save water outdoors? — require consideration of multiple factors.
There’s the precipitation rate — the amount of water an irrigation system puts out, in inches per hour. There’s also the soil intake rate, or the rate at which the soil absorbs water, which varies depending on the type of the soil. It goes without saying that there can be a lot of waste when an irrigation system emits water at a faster rate than the soil can absorb.
In addition, of course, gardeners must consider their plants’ water needs and the local climate. To assist with this, the state created the Water Use Classification of Landscape Species (WUCOLS), a database that classifies more than 3,500 plant groups according to their irrigation needs in six different climate regions of California.
Another notable takeaway from this session was the fact that in the Bay Area, rainfall can provide almost all the water most landscapes need for about five months of the year. Adjusting irrigation systems each season can make a big difference in water savings.
Overall, this workshop made it clear that the often-repeated water conservation advice to “lose the lawn” is only half the battle. Optimizing irrigation systems is the other critical step.