Happy Jacks is the first of 6 dams downstream from the source of the Tumut River. Captures spring snowmelt for diversion down the intake shaft to Lake Eucumbene. The Tumut and Happy Jacks Rivers flow is usually released via river outlet conduits through the base of the
dam. If these are closed the
dam will spill if the diversion shaft is also closed. The pondage is only likely to be seen by keen skiers or cyclists as it is 9 km from the main road. See You Tube for spill March 2012.