This paper discusses some of the problems encountered with water ingress on the 72km of tunnels on this project. Grouting is always a significant portion of dam projects and with the quantities of water expected in the tunnels, was also going to be an important element of the underground works as well. However it is unlikely that anyone could have foreseen the extent of the problems to be encountered with the water inflows and grouting requirements actually being experienced. Grouting to deal with water problems also contributes a ground support element, improving the stability of the rock mass.