Structural measures as part of the concession renewal for water use. Design, owner’s support and local site supervision for the renewal of the low head scheme on the Limmat. The concession water volume for the operation of the Dietikon HPP is 120 m3/s. The residual flow was set in the new concession at 10 m3/s in the winter half-year and at 15 m3/s in the summer half-year. Based on the capacity of the existing headrace channel, a distribution of 95 m3/s of the design charge was chosen for the main power plant and 25 m3/s for the new ecological discharge power plant. The works included: - Retrofit of the main power plant with replacement of the two vertical Kaplan turbines from 1931/32 with new “fish-friendly” turbines (Q = 2 × 47.5 m3/s, HN = 3.4 m, P = 2 × 1.7 MW); - Construction of a new power plant to turbine the ecological discharge with a Kaplan bulb turbine (Q = 25 m3/s, HN = 3.1 m, P = 770 kW); - Construction of two new fish ladders for the upstream migration; - Restoration of the downstream migration by two horizontal trash racks (B x H=22.8 x 5.9 m, spacing 20 mm) at the ecological discharge power plant and upstream of the main power plant; - Adaptation of an existing channel for fish downstream migration; - Reinforcement of the banks of the headrace and tailrace channels; - Replacement of the boat ladder. SIA phases 32, 33, 41, 51, 52 and 53.