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UBC Undergraduate Research

UBC Groundwater Emergency Water Supply Project Durrant, Kaede; Nickel, Andrew; Miller, Andrew; McRae, Natalie; Nubaira, Anha; Qin, Xiaoying

Abstract

The University of British Columbia (UBC) Point Grey Campus is located within the region known as the Cascadia Subduction Zone. Scientists have indicated that a large magnitude earthquake is likely to occur in this region. When this earthquake happens the potable water supply mains going through the University Endowment Lands (UEL) may be cut off. The UBC Social Ecological Economic Development Studies (SEEDS) Sustainability Program has been exploring ways to provide water to the residents in such an event, so as to improve their resiliency under trying times. A leading option in their search is to utilize the water found in aquifers that are located below UBC, in the Quadra Sand layer. This final design report explains in detail how this will be achieved and also provides final detailed drawing sets. There are two aquifers in the Quadra Sand layer, containing about 5 and 15 metres of available water, respectively. During an emergency, there is enough water in these aquifers to provide potable water for the UBC residents for a period of about seven days. The main objective was determining what flow could be produced from a well installed in these aquifers. It was determined from our analysis that a well installed at a suitable location could produce around 15 litres per second. The next objective considered was understanding the demand flow rate. From analyzing the current usage some important areas came to the forefront: residential, academic research, and the hospital. Accommodating these and reducing in areas such as irrigation and laundry, brought the average demand to around 67 litres per second. Wells were located based on the thickness of the aquifer and available surface space. Additionally, drawing water from one well can impact the available water at a nearby well. This calculation was done and it was determined there will be enough water for all the wells to draw continually for the 7-day emergency period. Also of importance for well location was the thickness of till cover at the surface, as excess till can cause delays in drilling. It was decided to use the existing water network to transport the well water to the residents, however, the well water would need to be treated before entering the network. The location for the treatment plant, storage reservoir, and pump station was based on proximity to the entrance of the two existing pressure zones, in order to minimize water main installation costs. The well water will first arrive at a treatment plant to receive filtration and chlorination, before proceeding to a storage reservoir. The inclusion of a 4,500 cubic metre storage reservoir helps balance the daily peaking demands and provides the campus with a source of water, ready to be used immediately after the onset of an emergency. This combination will provide an average flow rate of 67 litres per second. The treated well water in the storage reservoir will be sent to the two existing pressure zones from the pump station. This system has been designed for reliability and to have a service life of 50 years, thereby meeting the needs of current and future residents. The first month of this project was spent researching wells, aquifers, precedent structures, campus demand and reservoirs. This collaborative process involved sharing ideas, walking through explanations, and documenting rationale behind decisions. After the initial research, a technical analysis was performed for the soil geology, the hydraulics, the environmental impact, the cost, the schedule and for the construction planning. The project is scheduled to start construction on May 1, 2021, completing on November 23, 2021. The final project cost is $6.5 million, as determined in the attached class A, cost estimate.This final detail design for the emergency water system will provide a seamless transition from a broken water supply main, to a treated well water supply system. Disclaimer: “UBC SEEDS provides students with the opportunity to share the findings of their studies, as well as their opinions, conclusions and recommendations with the UBC community. The reader should bear in mind that this is a student project/report and is not an official document of UBC. Furthermore readers should bear in mind that these reports may not reflect the current status of activities at UBC. We urge you to contact the research persons mentioned in a report or the SEEDS Coordinator about the current status of the subject matter of a project/report.”

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Attribution-NonCommercial-NoDerivatives 4.0 International