* NASA-GRACE satellite data indicates increase in groundwater and snow water equivalent.

* Drought conditions still widespread, but NASA scientist says "there are signs of improvement."

* Increased precipitation and conservation efforts driving water gains.

Satellite data from NASA's Gravity Recovery and Climate Experiment (GRACE) shows that California is experiencing a slight increase in groundwater and snow water equivalent (SWE). This is positive news for California, which is currently in the midst of a severe multi-year drought.

"The GRACE data shows that there is a lot of variability across the state," said Thomas Piechota, a research scientist at NASA's Jet Propulsion Laboratory (JPL). "Some areas are still seeing declines in water storage, but overall, there are signs of improvement."

GRACE measures the changes in Earth's gravity field, which can be used to estimate the amount of water stored in aquifers, snowpack, and other water bodies. The mission has shown that California's water storage declined rapidly from 2007 to 2014. However, the GRACE data shows that the decline slowed in 2015 and that water storage actually increased in some areas in 2016 and 2018.

"In northern California, we had two very beneficial rain events during October 2016 and January 2017," Piechota said. "These events helped to replenish surface reservoirs, which are now at near average levels. The amount of water stored in the Sacramento River basin and in the San Joaquin River basin is now greater than the amount of water in those basins last year."

The increased precipitation has also helped to increase SWE in the Sierra Nevada mountains. SWE is the amount of water that would be produced if all of the snow in the mountains were to melt.

Piechota said that conservation efforts are also playing a role in the water gains.

"Californians have made a real effort to conserve water," he said. "Even as California's population continues to grow, the state is using less water than it did 15 years ago. That's a really impressive accomplishment."

Despite the gains in water storage, drought conditions are still widespread in California. However, Piechota said that the recent data suggests that the drought is starting to ease.

"We're not out of the drought yet, but we are seeing signs of improvement," he said. "If we continue to conserve water and we have a few more wet years, we could see California's water storage return to normal levels."