North Fork Dam is located near the City of Asheville in Black Mountain, NC, on the North Fork of the Swannanoa river.
Built in 1952 for water supply purposes, it is owned, operated and maintained by the City of Asheville.
Project features include the main dam, saddle dam, gated spillway and new auxiliary spillway equipped with semi-labyrinth shaped reinforced concrete Fusegates.
The dam was classified as high hazard, since the current discharge capacity of the spillway was inadequate and the dam would have been overtopped for floods more than 60% of the PMF.
In order to pass the PMF below the Maximum Water Level, a 60.96 m wide auxiliary spillway with a broad crested weir was constructed between the main and saddle dams.
The new spillway includes a bridge overpassing the weir, which is supported by three 1.83 m wide piers dividing the spillway sill in four 15.24 m wide bays and extending downstream of the sill. The piers also contain hollow sections to accommodate the inlet wells and the interconnecting pipes of the Fusegates.
There are 2 Fusegates at each of the 4 bays with a height of 4.88 m and width of 7.60 m.
The Fusegate solution allowed for minimizing the dimensions of the new spillway while offering a reliable and low maintenance spillway control system.