Investigations identified five alternative schemes at the Pleasant Valley site, and one scheme at the Tamblyn's Orchard site. Initially Site No. 4 at Pleasant Valley, about upstream from Tamblyn's Orchard was favoured. Subsequent detailed design studies however found that Tamblyn's Orchard at Coal Creek where the river exited the Roxburgh Gorge near the town of Roxburgh offered the fullest possible head and thus the most power output, better tailwater conditions, the best access and would be closest to suitable locations for both construction and permanent villages.