I grew up in the Omarama, Waitaki area. If you want pristine mountan water you must fish the upper Arhurri river. There is a road off to your right about ten k north of Omarama when heading south to the Lindas pass. it is a public road but travels through two sheep stations (Walkers used to have the second station). Good etiquitte to take the days newspaper with you and drop in at the station house on the way up and let them know you are there. The river is walking distance from the road and there are a couple of river crossings if you go well up. It is light water but stunning location and some nice trout. Fly only water.