March 11, 2014 | Water in the West | Insights
Figure 1. All fountains on the Stanford campus have been turned off to highlight the current California drought.
Despite recent rains, the drought continues with record low precipitation across most of California. Many communities are struggling with low water supplies, with some nearly running out. At Stanford, a diversified water supply portfolio, water efficiency investments, and recharged groundwater levels put the campus in an enviable position for dry spells. Although some of this is certainly due to good fortune, many of the steps Stanford has taken could serve as a model for other communities.
At a panel convened by Water in the West on the California drought recently, Tom Zigterman, the Associate Director of Water Services and Civil Infrastructure at Stanford University, discussed the historical and current operations of Stanford’s water supplies.
Groundwater was the main water source for Stanford in the first half of the 20th century. As a result, groundwater levels plummeted from 87 feet to over 200 feet deep (Figure 2). In 1960, Stanford started tapping into imported water from the San Francisco Public Utility Commission (SFPUC)’s Hetch Hetchy system, with an allocation of 3 million gallons per day. Since then, this high-quality snowmelt has been Stanford’s main potable water supply. The regional water distribution pipes go right by the Stanford campus.
Figure 2. Depth to groundwater over time.
Although Stanford has been very fortunate to be able to tap into this supply, it has taken important steps to diversify its water supply, and to limit its reliance on the high value Hetch Hetchy water for anything other than domestic water. These are the steps that will really cushion the impacts of the drought on Stanford's water supply.
Water planning is about responding and adapting to challenges. Stanford’s water troubles were not over with the addition of imported water. Water demands on campus quickly rose to meet the SFPUC allocation. By the late 1980s, Stanford was in danger of surpassing its SFPUC allocation. It responded by shifting irrigation of the golf course and campus landscaping from high-quality imported water to local surface water sources from Felt and Searsville Reservoirs, called “lake water”. This diversification relieved pressure on the main water supply. In more recent years, the campus aggressively undertook water conservation with retrofits, including plumbing and leak detection, leading to declining total domestic water use even as the campus continued to grow.
Finally, Stanford is working to increase its reliance on recycled water. Twenty buildings around campus use recycled water for non-potable indoor use, including the School of Medicine, Science and Engineering Quad, and the Business School. At the Yang and Yamazaki Environment and Energy Building (Figure 3), which has been awarded a LEED Platinum Certification in operations and maintenance, real-time water use can be tracked online. This easily accessible data provides a great sense of Stanford's reduced reliance on drinking water for irrigation and other non-potable uses. Overall, Stanford has reduced its indoor water use by approximately 500,000 gallons a day over the past fifteen years, although lake water usage for irrigation has not declined (Figure 4). It is continuing to work to reduce this number.
Figure 3. The Yang and Yamazaki Environment and Energy Building on Stanford Campus.
Figure 4. Domestic (indoor) water use and “Lake Water” (outdoor) water use from 1999 – 2012.
In a move that recognizes the direct linkage between water and energy, the University is investing in a new energy plant for Stanford due to be completed later this year. Once operational, the new plant will reduce the University’s potable water use from power production by 70 percent.
Over the decades, groundwater levels beneath the campus have been able to recover, stabilizing now at around 70 feet deep. This recharged groundwater serves as an important back-up potable water source. If SFPUC were to cut back on Stanford's Hetch Hetchy allotment for whatever reason (e.g. reduced snowmelt, sustained drought, etc.), that groundwater will be able to support the campus, at least for a while.
Stanford's water use is not without problems. For example, its reliance on local streams for irrigation may have an impact on the ecosystems of those streams, and Stanford is currently studying the impacts of Searsville dam and looking at options for its future. Stanford's faculty residential neighborhood still uses potable water for lawn irrigation. In addition, not all communities are fortunate to have such a range of options to rely on. Nevertheless, Stanford has taken some basic steps to make its water supply more secure that other California communities should emulate if possible: it has decreased its water use, increased its reliance on recycled water, and nurtured its groundwater for times of shortage. Given the diversified water sources, water efficiency and power investments, and recharged groundwater, this portfolio gives the University some flexibility to withstand droughts, which are inevitable in California.
By Janny Choy