ARVIN, Calif. — In the southern San Joaquin Valley, where roads cut through thousands of acres of orange groves, grapevines and carrot fields, a canal reaches a linchpin that keeps the farming economy going: dozens of oblong ponds filled with shimmering water. While many parts of California’s Central Valley are struggling to counter widespread overpumping and declining underground water levels, the irrigation agency here is using the ponds to effectively swallow gulps of river water, getting it to seep into the soil and recharge the groundwater. “That sandy ground, when you put the water on it, it percolates into the groundwater and it recharges,” said Jeevan Muhar, chief executive officer of Arvin-Edison Water Storage District. “So it’s underneath us. We can see that water come up.” The irrigation district tracks groundwater levels. In dry times, when it needs to tap into stored water, it uses dozens of wells to pump it out and send it flowing to farms. The Tejon Spreading Works is part of a network the Arvin-Edison Water Storage District uses to recharge groundwater. A …