regardless of whether the pumps are on to pump water south or not, freshwater is necessary to offset the tidal push of seawater inland. with an increasing sea level, more water is needed to off set the additional tidal push. proof of this is anglers are now catching halibut and other predominately saltwater species in franks tract, which is ordinarily more fresh water than brackish...until relatively recently. the tide is coming in higher than it has in the past and there is less water falling out of the sky and banked in our reservoirs to combat the inflow. combine that with federal mandates to protect things like delta smelt and winter run Chinook etc and the shell game of how much water is released and from where gets more complicated. combine that with the "need" for water down south for humanity and/or agriculture with water right claims and things get even more interesting.