Long Beach’s origin story is awash in water. It was a resort and farming town of transplanted Iowans who got water from aquifers under Signal Hill; the drill bits even found a more lucrative resource underneath: oil. Then when the city outgrew the wells, the Metropolitan Water District was forming and voters jumped in. Freshwater for drinking and saltwater for playing. The Pike, the L.A. River, the aquarium and Alamitos Bay, then there are the coastal wetlands that have largely disappeared, though, thanks to climate change, those wetlands seem to be coming back. The city’s evolving relationship with water is the subject of the Historical Society of Long Beach’s new exhibit “Water Changes Everything.”