The Carson City Freeway drainage system is being designed in coordination
with major drainage improvements to be constructed by Carson City. The resulting drainage system will provide a coordinated and functional 100-year drainage system to detain, intercept, and convey storm drainage within the freeway
corridor to the Eagle Valley Creek channel that ultimately discharges to the Carson River. This coordinated system includes three major detention basins (Shenandoah Heights, Eagle Canyon Creek, and Silver Oaks
areas), three sediment basins (Shenandoah Heights, Eagle Canyon Creek, and Silver Oaks), and one large regional water quality basin (Lompa Ranch area) at the downstream terminus of the project. The
drainage system will also include a series of channels, box culverts, and pipes within the freeway corridor and US 50 to intercept and convey those flows to the water quality basin that will provide water
quality treatment of the stormwater discharging from the Carson City Freeway and US 50 as well as the surrounding areas before it reaches the Carson River. The facilities that will be located within
the NDOT right-of-way will be constructed by NDOT. The remaining facilities will be constructed by Carson City under separate construction contracts. The drainage system within NDOT right-of-way will be completed in
two phases. Phase 1A (Advanced Bridge Contract) will include conveyance facilities from Northgate Lane to just south of College Parkway, drainage facilities needed for the re-alignment of
Arrowhead Drive, and a temporary water quality treatment facility to collect sediment produced from Phase 1A construction activities. The conveyance facilities in this area must be completed before
bridge construction at Northgate, Emerson, and College Parkway to avoid disturbance near the bridge foundations at a later date. During the construction of Phase 1B, the remainder of the drainage
facilities will be completed, and the temporary water quality basin will be replaced by a permanent facility within the Lompa Ranch area. The drainage system is the result of years of cooperative planning
between NDOT, Carson City, the U.S. Army Corps of Engineers, U.S. Fish and Wildlife Services, Nevada Division of Environmental Protection, Nevada Division of Wildlife, and many other agencies.
The resulting system will not only provide for the drainage associated with the Carson City Freeway to provide adequate protection of the freeway improvements but will also provide
substantial flood control benefits for Carson City and a substantial reduction in limits of flooding as currently shown on the FEMA Flood Insurance Rate Maps as well as a reduction in peak flows and water
quality improvements throughout the entire drainage system and reduce the cost of drainage facility construction now and in the future. 
Drainage - Phase 1
Carson City Floodplain
Carson City Freeway Drainage System
