Tough trip tagged

Taupo Times, Volume 23, Issue 58, 23 July 1974, Page 5

Tough trip tagged

At least one trout has made the journey from Lake Rotoaira to the Tokaanu tailrace — via the Tokaanu tunnel and powerhouse. A tagged trout from the lake has been captured at the tailrace. This was revealed in a report to the Federation of Lake Taupo Angling, Shooting and Boating club's conference with Internal Affairs' officers held at the weekend. The conference chairman, Dr G. R. Williams, said the tailrace had proved a popular and

productive angling area under certain conditions. Trout had been attracted to the area along with smelt and carp, and good numbers of trout had been taken when the power station had been operating. Sporadic small losses of smelt had occurred and a substantial loss in November caused some concern. "Investigation to date tends to eliminate temperature and chemical factors," said Dr Williams. "Pressure changes involving rapid acceleration and deceleration of water at the turbine outlets appear to be the cause. "No similar large loss

has since occurred." Fish between the Waikato Falls and the Poutu intake were successfully removed in November, followed by the interception of the flow to the Poutu intake early in December, said Dr Williams. Some 500 fingerlings were salvaged when an area below the intake structure was de-watered. Because of low flows in the Tongariro River only mfnimal diversions occurred. Lowering the stream bed proved unnecessary as the velocity barrier was sufficient to prevent trout entering the aqueduct