Under their IDIQ contract with the NRCS, DJ&A provided engineering services for assessment of flood hazards associated with nine (9) USFS dams varying in height between 6 and 50 feet within the Mount-Baker Snoqualmie, Colville, Rogue River-Siskiyou, Siuslaw, and Wallowa-Witman National Forests in Oregon and Washington.

Site visits were conducted at each dam to observe and document the condition of the existing dams, the basin upstream, the downstream reaches, and potential downstream hazards. Additional activities included screening level assessments to assess inundation of potential hazards, dam breach analysis and modeling, hydrologic analysis, and dam hazard classification reports.

Key Services

• Background research and preliminary data collection
• Site visits including dam surveys, condition assessments and screening level assessments
• Dam breach analysis using HEC-HMS and/or HEC-RAS
• Hydraulic analysis for flood-induced breach and auxiliary spillway flow inundation using HEC-HMS
• Preparation of inundation maps with all downstream hazards
• Development of hazard classification assessments