Terraphase prepared the technical drainage study and downstream two-dimensional flood analysis for the Moya Boulevard Extension and Air Logistic Facilities project at the Reno-Stead Airport in Nevada. As the first phase of a larger commercial development plan, the project required alignment with the related area drainage master plan and careful consideration of flood risk to nearby residential areas.

Scope of Services

Terraphase’s efforts included upstream hydrologic analysis, runoff volume mitigation determination, and design of retention basin, storm drain, and channels. Our team also performed downstream two-dimensional hydraulic modeling to determine the impacts of undersized downstream channels on adjacent residences located along the overbanks. Upstream hydrologic analysis was crucial as the project is downstream of planned major detention basins designed to attenuate upstream flows passing through the site. Runoff volume mitigation was required due to the project’s location within the Silver Lake closed watershed and was achieved through Terraphase design of on-site retention basins. The site storm drain system was designed to convey peak flows from commercial areas and the proposed road to the flood channel.

Notable Accomplishments

• Completed major regional flood retention/detention alternatives analysis (HEC-HMS)
• Performed HEC-RAS two-dimensional modeling of multiple flood attenuation scenarios
• Aligned project drainage infrastructure with the regional Area Drainage Master Plan
• Delivered drainage solutions that addressed both on-site and downstream flood risks