Steps to determine the hydraulic horsepower (whp) for pump problems: 

1) Determine (h_A) by rearranging the Bernoulli equation.   

2) Apply (h_A) into the equation found in the table along with the flow rate (gal/min or ft3/sec), and the specific gravity (SG, typically given), OR use the mass flow rate equation (last column in the table).

h_A = (p/γ)₂ - (p/γ)₁ + (V²/2g)₂ - (V²/2g)₁ + (Z)₂ - (Z)₁ + h_ƒ

h_A (Qgpm)(SG) / 3956 or h_A (Qcfs) (SG) / 8.814

For the mass flow rate = (8.34 lb/gal for water)(flow in gal/sec)(SG) = lb/sec

h_A (mass flow)/550