Of fields and faucets

Engineering students are developing a source water protection plan. (Danny Abriel Photo)

The village of Port Williams in Nova Scotia’s Annapolis Valley prides itself on being one of the best places to experience the world’s largest tides. But its water concerns don’t begin and end with the Bay of Fundy; the village is also deeply concerned about maintaining the quality and safety of its drinking water.

Roughly half of the village’s population is serviced by the municipal water supply, which relies on a series of wells drilled into a sandstone aquifer. The areas surrounding these wells are mainly privately-owned and used for agriculture, meaning that both organic and inorganic fertilizers are being applied.

“The challenges the water utility in Port Williams face are typical of many small communities in rural Nova Scotia, and in the Annapolis Valley in particular,” explains Rob Jamieson, Dalhousie environmental engineering professor. “Due to their proximity to agricultural activities they’re very concerned about pathogens, as well as contaminants such as nitrate-nitrogen.”

"The latter,” he explains, “when present  at high levels in drinking water can lead to a disorder called methemoglobinemia. Infants are especially susceptible to this illness, which results in a reduction in the oxygen carrying capacity of red blood cells.”

With funding support from Agriculture and Agri-food Canada’s National Water Supply Expansion Program, two groups of environmental engineering students, working under Dr. Jamieson’s supervision, have been developing a source water protection plan for the Village of Port Williams. One group is focusing on protecting the aquifer from pathogen contamination, while the other group is examining strategies to reduce nitrogen loading to the aquifer. Their efforts represent a year’s work, the culmination of their capstone design project.

“The project has given us an opportunity to take what we know about hydrology and pathogen transport, and build our own model to better understand what’s happening in Port Williams,” explains Jacqueline Gillis, one of the students.

Bringing together pre-existing research and analysis with their own evaluation of the hydrologic and soil conditions surrounding the wells, the students have linked a 3-D ground water flow model to a GIS (Geographic Information System) based surface vulnerability model, providing a more comprehensive analysis of where the potential threats to the village’s water supply may be. The final product will be a vulnerability map for the aquifer recharge area, with specific management recommendations for land parcels based on their relative vulnerability.

For the students, the project is an opportunity to tackle a real-world problem, with all of its complications and challenges.

“It’s really taught me that to complete or implement a project, you not only need to be able to recognize social and economic realities but work them into your design,” explains student Lisa Butler. “All the good ideas in the world are pointless if they don’t get used.”

Meghan Swanburg, their teammate, agrees. “Ideally, we want to make sure that our recommendations are practical – the sort of thing that the community can buy into,” she says.

The students presented their findings and recommendations to both their colleagues and professors in environmental engineering, as well as representatives of the village of Port Williams and Agriculture and Agri-Food Canada.