Environmental impacts and cost analysis of low impact developments in arid climate: A case study of okanagan Valley (Canada)

Low impact developments (LIDs) are becoming increasingly popular in North America as viable solution for sustainable runoff management. Although hydrological performance of LIDs in relation to climates is readily available, there is still a gap on the evaluation of environmental and economic impacts of these infrastructures. We have evaluated the cradle-to- site lifecycle environmental and economic impacts of four LIDs using a case study of the stormwater management system at UBC Okanagan campus in BC, Canada. The environmental impacts and costs are determined via ReCiPe, TRACI, and net present value (NPV) method, respectively, and incorporated to obtain eco-efficiency of these LIDs. We found that the box planter and naturally occurring wetland on campus are the best LIDs with lower impacts (approximately 2.5% of the total impacts) than other LIDs. The cost savings from wetland are enormous due to zero construction and periodic maintenance after every five years. The box planter and wetland occupy the most favorable quadrant III of the eco-efficiency matrix whilst, bioswales and rain gardens are found in quadrant IV and I, respectively. When compared to the constructed wetland, an increase in the economic impacts is found without any influence on the eco-efficiency of the overall placement on eco-efficiency matrix. The maintenance phase contributes more to environmental impacts than the construction, whereas the life cycle cost analysis shows the opposite.