Public Works Department in 1919. Despite a lucrative salary offer he turned it down. SEPB was eventually able to obtain the services of Herbert P. Thomas, who in January 1922 took up the position, which was now as an employee of SEPB. In the interim G.F. Ferguson who had been taken on from Hay and Vickerman was acting engineer. Work restarts Once he had taken up his duties Thomas reviewed the scheme and identified that the average flows from Lake Monowai would be less than had been originally been estimated. Taking into accounts what had been built to date he adopted the ideas of Alfred Walker and proposed that to construct a short dam to divert to the Monowai River through control gates, then a second longer earth dam would be built to raise the lake level by an additional 8 ft compared with the previous scheme. The water would flow through the control gates to a headpond where a weir would divert it into a canal to carry the water to a shortened steel pipeline. He also proposed to install only one 4 MW generator and later a 2 MW unit. He also proposed modifying the transmission system. His design was adopted by the SEPB board. With the change to a steel pipeline, the one million of heart totara that had been cut and milled in preparation for making the previous pipeline design was used for lining houses at Monowai and the rest sold. Work recommenced at Monowai in early 1922 with Thomas estimating that the station would be generating power by September 1923. Soon the workforce on site had risen to 800, working three shifts a day. To build the control gates, from the terminus of a road that had been built along the northern side of the Monowai River a raised trestle tramway was built southwards across the lakes natural outlet to convey construction materials and the workforce to the arm of the lake where the control gates were built. Once they had been finished the area under the trestle tramway was lined with timber to hold back the water as the area was filled with earth. the core of the dam was formed from two rows of steel-shod piles driven seven feet into the rock. These were surrounded by clay in bags and then sheathed in totara timber. The remaining fill consisted of unreinforced concrete, broken