Comer Debris Basin Removal Feasibility Study Client: Santa Clara Valley Water District, California Kennedy/Jenks Consultants Completed: 2001 PWR, as a subconsultant to Kennedy/Jenks Consultants, provided professional services for the feasibility study to remove an existing debris basin and headwalls on Calabazas Creek located in California with steep terrain that results in a high slope gradient. The project involved evaluating the impact of removing the existing sediment basin on Calabazas Creek from the perspective of sediment transport and river morphology. Channel stability evaluations were conducted using an incipient motion and armoring analysis and an analysis of equilibrium slope was conducted in order to develop an estimate of sediment continuity for the proposed condition. HEC-RAS hydraulic modeling was performed for determining the characteristics of the stable channel geometry. Project work also included reviews of historic information and aerial photographs, evaluations of several alternatives from do-nothing, partial removal to full removal, and sediment transport analyses to evaluate the short and long-term impacts of each alternative.     Hydraulic and Scour Analysis Table Rock Road Bridge Client: Department of Roads and Parks; Jackson County, Oregon Completed: 1994 PWR staff conducted hydraulic/scour analysis for the replacement of the Oregon Department of Transportation's Table Rock Road Bridge over the Rogue River in southern Oregon. The work included a no-rise hydraulic analysis for FEMA, two-dimensional hydraulic modeling, and scour analyses for the bridge piers and abutments. A two-dimensional hydraulic model was used to reproduce the significant features of the observed water surface elevations and the velocity fields throughout the project site. Particular detail was paid to the bridge piers and the City of Medford's drinking water intake, located just downstream from the existing bridge. The objective was to assure that the replacement bridge would have no adverse impact on the flow characteristics of the Medford water intake or at the new bridge's piers and abutments. A one- dimensional HEC-2 hydraulic model was also developed for the no-rise analysis. An evaluation was also conducted on the present river channel alignment to maintain favorable flow conditions approaching and passing the water intake. This evaluation included preparation of design alternatives for protecting the intake.     IDIQ: FHWA Hydrologic/Hydraulic Services Client: Federal Highway Administration Completed: Ongoing. Pacific Water Resources, Inc. is entering the third year of its second 5-year IDIQ contract with the Federal Highway Administration (FHWA). These contracts cover a wide range of services on a variety of assignments including: field reconnaissance, assessment of flood patterns, fluvial geomorphology, hydrologic and hydraulic analysis of rivers and river structures, fish passage studies and remedial designs, bridge scour analysis and countermeasures designs, evaluation of stream bed material and stream classifications, and sediment transport studies.   These services have mainly been performed in support of roadway upgrades along rivers and streams in Alaska, Idaho, Washington, Oregon, Montana and Wyoming. Projects performed over the last seven years have included bridges in Glacier National Park (Montana), Yellowstone National Park (Wyoming), North Cascades National Park (Washington), Denali National Park (Alaska) and Crater Lake National Park (Oregon). Assignments normally involve hydrologic and hydraulic analysis using regional regression equations, HEC-HMS or HEC-RAS, fish passage mitigation, long-term streambed aggradation and degradation studies using HEC-18 and development of bridge scour counter measures. Unusual assignments have included the effects of glacier melt on river morphology and flooding in various locations in Oregon, Washington, and Alaska.   The Malheur National Wildlife Refuge is a typical example of a recent assignment for FHWA. PWR analyzed over 10 bridge and culvert structures in this refuge renowned for its wetlands and varied bird species. The project involved assessing the existing crossings for compliance with fish passage criteria and reconnecting flood plain areas. Special consideration was given to the basin's complex hydrology, channel structure, water rights issues and an adjacent Native American historic site. The assignment included hydraulic modeling (HEC-RAS) to evaluate flow velocities at structures as well as geomorphic studies to assess scour and sediment transport potential. Based on PWR's recommendations five structures were replaced using design criteria developed by this task.     Sand Lake Estuary Mitigation Client: Federal Highway Administration; Tillamook County, Oregon Completed: 1999 PWR performed a site reconnaissance to review the potential impacts of breaching an existing dike to promote restoration of this historical saltwater marsh system. The work involved estimating the culvert opening area required to meet hydraulic, sediment transport and scour concerns. Identified impacts and issues included saltwater intrusion into the groundwater table and possible flooding of an existing residence. The final report identified additional hydraulic, sediment and scour studies to be performed, a groundwater monitoring plan to document baseline and changed conditions as well as estimated costs of professional services required for future phases of work.