Diamond Fork System

The Diamond Fork System of the Bonneville Unit, Central Utah Project conveys water collected by the Strawberry Aqueduct and Collection System, and stored in Strawberry Reservoir, through the Wasatch Mountains to the populous Wasatch Front via a system of underground pipelines and tunnels. Diamond Fork System consists of the Syar tunnel, Sixth Water Aqueduct, and the Diamond Fork Pipeline.

The DFS conveys an annual average of 101,900 acre-feet of CUP water. In partnership with the Strawberry Valley Project (SVP), constructed by Reclamation in the early 1900’s, the Diamond Fork System also conveys 61,500 acre-feet of SVP water for a total annual average of 163,400 acre-feet of trans-mountain water deliveries.

Diamond Fork System Map

Map of the Diamond Fork System of the Bonneville Unit

The Diamond Fork System receives water from Strawberry Reservoir via the Syar Tunnel which begins in Strawberry Reservoir itself. From the tunnel outlet, water enters the Sixth Water Aqueduct, which consists of the Sixth Water Pipeline, Sixth Water Shaft, and Sixth Water Tunnel. A flow control structure (the Sixth Water Flow Control Structure) at the end of the tunnel provides for release of water to upper Sixth Water Creek to allow dewatering for inspections and repairs, and to maintain a minimum in-stream flow to benefit sport fisheries in lower Sixth Water Creek. The outlet could also be operated in case of emergencies.

Beyond the Sixth Water Flow Control Structure, water enters the Diamond Fork Pipeline, itself a series of tunnels, siphons and pipelines, for conveyance to the Spanish Fork River. An overflow and outlet structure at Monks Hollow, on Diamond Fork Creek, also allows for release of water to Diamond Fork Creek as needed for inspections, repairs, emergencies, and to maintain a minimum in-stream flows to benefit sport fisheries in lower Diamond Fork Creek. At the confluence of Diamond Fork Creek and the Spanish Fork River, the Spanish Fork River Flow Control Structure releases Strawberry Valley Project water to the Spanish Fork River, to be diverted by other SVP project facilities for the customers of that federal water project. Bonneville Unit water enters Provo Reservoir Canal Pipeline of the Utah Lake Drainage Basin WateDiamr Deliver System (ULS) for conveyance to the ultimate CUP customers.

Another part of the Diamond Fork System is the now-retired Strawberry Tunnel, the original trans-mountain delivery feature of the Strawberry Valley Project. Constructed in 1906-1912, the tunnel is beyond its useful life and now serves the Diamond Fork System as a means to convey minimum in-stream flows to upper Sixth Water Creek to benefit sport fisheries, and as a back-up means to deliver some Bonneville Unit water in the event either the Syar Tunnel or Sixth Water Aqueduct are not operable. A Strawberry Tunnel turnout, completed in June 1998, connects the old Strawberry Tunnel with the new Syar Tunnel and can convey up to 200 cfs of Bonneville Unit water if necessary.

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