Ron Berry is what one might call a power player when it comes to basketball.It’s not that the longtime manager of the Tri-Dam Project plays hoops. He deals in water.And the best way to describe the water that flows from the reservoirs he oversees on the Stanislaus River Middle Fork and irrigates 114,000 acres of farmland, flows through taps serving 180,000 urban users, and is providing the revenue needed to install state-of-the-art farm irrigation systems and ultimately lower power costs in Manteca, Ripon, and Escalon by 15 percent is by using basketballs.“People have a hard time grasping what cubic feet per second means when it comes to water,” Berry told Manteca Rotarians gathered at Ernie’s Rendezvous Room earlier this month. “So we tell them to think of basketballs.”It takes 685 cubic feet of water dropping per second — or the volume of 685 basketballs passing a point in a given second — in a penstock or tunnel to spin the generators at Donnells Reservoir that generates 72 megawatts of electricity.