On the heels of record rain and snow in California, some local water agencies are experiencing a bonanza of surplus supplies. But others that rely on groundwater are still feeling lingering effects of the state’s five-year drought. Perhaps the most visible sign of this summer’s water feast can be seen from the I-5 freeway north of Balboa Boulevard, where the historic Los Angeles Aqueduct crosses into the San Fernando Valley. It’s at that point where water in the aqueduct tumbles down an open-air staircase of concrete blocks called the Cascades.