Three reservoirs A, B and C are interconnected by pipes as shown in the below figure Water surface elevations in the reservoirs and the Piezometric Head at the junction J are indicated in the below figure. Discharges Q1, Q2 and Q3 are related as

• Q1 + Q2 = Q3
• Q1 = Q2 + Q3
• Q2 = Q1 + Q3
• Q1 + Q2 + Q3 = 0