Assessing the water balance and future consumption scenarios for demand management of the Aldergrove aquifer in B.C.

Many municipalities in the Lower Fraser Valley rely on groundwater as their main source of water. With the rapid increase in population and land use intensification, excessive groundwater extraction is of growing concern. There is evidence that current extractions from the Aldergrove aquifer in Langley exceed sustainable rates but little quantitative information is available about water recharge and demand. The aims of this research is to assess the current status of this aquifer in terms of recharge, storage and discharge, with the use of current and historical climatic, geological, land use and consumption data. Consumption between 1995 and 2005 was used to project demands in 2015 based on 3 different future scenarios, and some demand management strategies were also evaluated. The results of the analysis suggests that the aquifer receives about 26 million m³ of recharge each year, and has a storage capacity of up to 200 million m³, with current water content less than 70% of capacity. Natural discharge is around 22 to 26 million m³, while current consumption is 7 million m³ . Of all the land uses, agriculture occupies the largest area and also uses the most water, accounting for over half of total consumption. Since the climate over the past 10 years has remained largely constant while urbanization has increased, the reductions in water levels are due to increasing consumption. Projections based on the 'business as usual', 'greater growth', and 'conservation' scenarios suggest that consumption will range from 6 to 11 million m³ by 2015. The evaluation of demand management strategies based on increasing efficiency of water use suggests that significant reductions can be achieved in the agricultural and residential sectors, which has a combined potential of reducing the current total annual consumption by at least 20%. However, these conservation efforts are insufficient by themselves to reduce consumption to 'sustainable' levels. The analysis shows that current extraction is unsustainable and unless drastic measures are taken to reduce water use and/or increase supply, the aquifer will not be able to continue meeting demands in the near future.Science, Faculty ofResources, Environment and Sustainability (IRES), Institute forGraduat