Dear EarthTalk: Given the multi-year droughts facing the American West, how are groundwater levels there holding up? —Charles Talarico, via emailGroundwater levels are the level of the water table below underground aquifers and are crucial to water security. Groundwater recharge is slow already, and drastically worsens during drought. In addition to the multi-year-long drought, several other factors contribute to the depletion of groundwater levels. Late January levels hover at 25 percent of the usual level, reducing the critical transfer to the underground aquifers.