Interactive: Slide over these photos to see the drought’s effect on some of the state’s big reservoirs

As of Wednesday, California’s two largest reservoirs, Shasta and Oroville, are more than 90% full, a significant reversal from the summer and fall of 2014, when the state was locked in severe drought. Folsom Lake is filled to about 86% capacity.

After four dry winters, storms have helped replenish these Northern California reservoirs with rain and runoff from the state’s relatively healthy snowpack. California’s complex water delivery system helps move the water from the northern part of the state, where most of the rain and snow falls, to the southern part of the state, where much of the population resides.

Drag the slider to compare the images.

Lake Oroville

Severe drought conditions are evident as houseboats are dwarfed by steep banks that show the water level down 160 feet from the high water mark at the Bidwell Bar Suspension Bridge over Lake Oroville on June 21, 2014. The same scene after snow melt and rainfall brought the reservoir to 96% capacity on May 12, 2016. (Allen J. Schaben / Los Angeles Times)

Bidwell Canyon Marina on Lake Oroville on June 21, 2014, and the same scene on May 12, 2016. (Allen J. Schaben / Los Angeles Times)

Bidwell Canyon Marina on Lake Oroville on June 21, 2014, and the same scene on May 12, 2016. (Allen J. Schaben / Los Angeles Times)

Folsom Lake

Severe drought conditions reveal over 600 empty docks sitting on dry, cracked dirt at Folsom Lake Marina, one of the largest inland marinas in California, at Folsom Lake State Recreational Area on Sept. 30, 2014. The same scene on May 11, 2016. (Allen J. Schaben / Los Angeles Times)

Lake Shasta

The Bridge Bay Marina at Lake Shasta reveals signs of severe drought June 22, 2014, when it was filled to only 37% of capacity. The same scene on May 11, 2016. (Allen J. Schaben / Los Angeles Times)

A long staircase leads to a dry lake bed at Lake Shasta, which was suffering under severe drought conditions June 22, 2014. The same scene on May 11, 2016. (Allen J. Schaben / Los Angeles Times)