The discharge rate of a water pump is 0.25 m$^3$/s. The diameter of the discharge and suction nozzles are 300 and 350 mm respectively. The measured pressure at the discharge end located 0.25 m above the centerline of the impeller is 150 kN/m$^2$ and the pressure at the suction gage located at the centre line of the impeller is 20 kN/m$^2$. Specific weight of water is 9810 N/m$^3$. The total dynamic head for the above installation in m is ______.