In which:

• b = width of the spillway or gate [m]
• g = acceleration of gravity = 9.81 [m/s2]
• Dd = sill height [m]
• He = upstream energy level [m]
• hdstr = downstream water level of spillway [m]
• hupstr = upstream water level [m]
• hs = dimension of opening under the gate [m]
• Q = rate of discharge [m3/s]
• uupstr = average rate of flow upstream [m/s]
• m = discharge coefficient or contraction coefficient [-]