The invention discloses a loss detection system to determine and monitor containment losses for open channel networks (10). The system includes at least first and second flow regulators (26, 28) to allow flow of liquid into and out of at least one pool (10) respectively. First and second flow sensors co-operate with respective flow regulators (26, 28) and a computational means communicates with flow regulators (26, 28) and the flow sensors to control operation of flow regulators (26, 28). The computational means determines the containment losses by calculating the measured flow into at least one pool (10) through at least first flow regulator (26) and subtracting the measured flow out of at least one pool (10) through at least second regulator (28).