Dependence of groundwater recharge in the Niles Cone Groundwater Basin on climate variability and inter-basin water transfers
The Alameda County Water District (ACWD) supplies water to the cities of Fremont, Newark and Union City. Approximately 40% of this supply requirement is met using water pumped from the Niles Cone Groundwater Basin. Since 1920s, the ACWD has managed recharge operations at Niles Cone and today the water for recharge is obtained from the State Water Project, run off from Alameda Creek Watershed or from direct rain that falls on the Niles Cone region. This paper examines the dependence of recharge operations on precipitation in the Alameda Creek Watershed. Using data from the past 20 years, the paper demonstrates the dependence of Niles Cone Basin on the outlier wet year of 1997-98 to maintain a net positive water balance with respect to levels in 1988-89. Further research using longer time series data of groundwater recharge should be able to provide more evidence of the extent of this dependence on heavy rainfall years to maintain net positive groundwater levels. Such research will be significant in ensuring urban resilience in the context of climate change scenarios we seem to be facing.