Student research under the direction of faculty members and staff has led to marked awareness and revised usage of water on the HMC campus. In 2007, teams of students, including those from HMC, documented the historical usage of key resources and utilities—electricity, natural gas and water—in order to establish baselines against which to compare future usage, and to identify targets for conservation programs. Multiple studies, including “Sustainability in a Desert: Water and Landscaping at the Claremont Colleges” by Annika Eberle ’09, Herbie Huff ’07, Trevin Murakami ’09, Corina Tom ’08 and Sam Brunswick CMC ’07, were published in the “Sustainability Audit of the Claremont Colleges.” These studies inspired Claire O’Hanlon ’09 to dig a little deeper and focus on water reclamation, research she pursued under the direction of Richard Haskell, professor of physics, and with funding from the HMC Center for Environmental Studies.

During summer 2008, O’Hanlon decided to investigate the question, what is a sustainable level of water usage at HMC?

Researchers at HMC and The Claremont Colleges had concluded that an environmentally sustainable level of water usage is 50 percent of the current usage level, since about 50 percent of HMC’s water must be imported from non-local sources, namely northern California. To meet that goal, it was recommended that the colleges consider water reclamation, including rainwater catchment systems and graywater systems. O’Hanlon set out to discover if either was feasible.

Graywater is water which is not contaminated as sewage (“blackwater”) but not safe enough to be potable (“whitewater”) and is typically used for toilets and irrigation. HMC’s graywater would include wastewater from baths, showers, sinks and washing machines (excepting water containing human waste). “About half of our water at Mudd is used for landscaping, and you don’t need to have completely potable water for that. So a lot of the water we use here is overtreated,” she said.

O’Hanlon explained that graywater needs to be treated rapidly to contain bacteria and other pathogens. A wetlands environment or spreading grounds in an area east of campus or a mechanical system to treat the graywater were two options she explored.

“I thought Mudd could start treating its own graywater here on campus, “she said. But her research found this to be infeasible.

O’Hanlon also looked at water catchment systems to determine if installing them on roofs and hardscape surfaces could help to alleviate wasted water.

“I found that if systems could reclaim all the rain that fell on building roofs and parking lots for a year, and if the college used all of that, we could save about 5 percent of the water we currently use, a surprisingly high amount,” she said. “However, for use on campus, maybe other than a little garden or other small project, you have to change the irrigation system because reclaimed water can’t be distributed through sprinklers. So we would need more drip irrigation systems.”

She realized that costs for graywater and water catchment systems far outpace the relatively cheap cost of water, which is subsidized by the state of California. HMC annually spends about $100,000 for about 39 million gallons of water. “If we were able to convince the colleges as a whole or the city of Claremont to consider wastewater treatment solutions, for example, then that would probably be more beneficial because of the economies of scale. Plus, HMC and The Claremont Colleges shouldn’t be in the business of treating water.”

Haskell, O’Hanlon’s faculty adviser, said that O’Hanlon’s report has become invaulable. “She concludes that a strong program of water conservation at the college, together with continuation of our current practice of replacing water-thirsty turf with native and drought-tolerant plants, and future capture of rain water and re-use of gray water will bring us almost to the 50 percent reduction in water use that we need to be truly sustainable.

“A water reclamation plant (sewage treatment) for the Claremont community could potentially provide water for landscape irrigation—at least 50 percent of our water consumption,” said Haskell. “It won’t be easy. There are a lot of technical challenges. But many constituencies within the community have come to the same conclusion, and the time seems to be ripe for serious discussion. Claire’s work is a great place to start.”

“Because we are historically and physically connected to a lot of water systems that are being drained and because we are over pumping our ground water supplies, it is in our best interest to the sustainability of the college to get down to a level of usage that we can sustain,” O’Hanlon said.