The flow rate Q, can be calculated using the tank volume,
Q=dV/dt
Where,
V- tank volume,
B- the bulk modulus of water,
dP/dt -the known pressure surge rate,
Q=dV/dt=(dP/dt)(V/B)
or
dV= (V/B)(dP)
Since water is virtually incompressible, only a small flow of water needs to be released at a rate on par with the pressure surge rate to prevent rupturing the tank.