The reform includes increased emphasis on zones that are more likely to impact aquifers (Ibid.). Groundwater is an important water source for California farmers, accounting for nearly 40% of irrigation withdrawals in average years (Maupin et at, 2014) and up to 60% in dry years. There are strong indications that groundwater overdraft is worsening: recent data show that the Sacramento and San Joaquin River Basins collectively lost nearly 31 km3 of groundwater between October 2003 and March 2010, or about 4.8 km3 per year (Famiglietti et al.,