More water — or less — could be sent cascading down the San Joaquin River through Stockton as a result of a State Water Resources Control Board meeting starting Wednesday. The board is considering revisions to the Bay-Delta Water Quality Plan, the document that sets goals for the amount and quality of what flows through major rivers surrounding the Delta. It’s the latest update to a plan that started in 1978 and has seen updates three times since. Because it involves California’s most precious commodity — water — any changes are sure to bring disagreements. The latest issue pits farmers, Native American tribes, water districts, environmentalists and others trying to get sufficient water to meet their divergent needs. At issue is just how much water should course through Northern California rivers to ensure that badly depleted fish stocks can be replenished.