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Douglas Williams PE, Page 2 of 2 FEMA Map Revisions/CLOMR's/LOMR's Piney Creek Cottonwood Creek Spring Creek Goldsmith Gulch City Park Drainageway Boulder Creek Sand Creek! Aurora South Boulder Creek Sterling West Toll Gate Creek Westerly Creek Cherry Creek Big Dry Creek Cub Creek Sand Creek Sand Creek Channel Improvements: Preliminary and Final Design D>r approximately 3 miles of extensive channel improvements on Sand Creek in the City of Aurora. Improvements include seven major drop structures, extensive channel excavation, erosion (;ontrol using soil cement, construction of a natural low flow channel and completion of a continnous bikeway/maintenance trail system. The project has an estimated construction cost of$5.0 million. Rosamond Park Drainageway Improvements: Final design for major channel improvements to approximately two miles of drainageway along Goldsmith Gulch in Denver. Designs include several major drop structures, two residential road crossings and utility improvements. Canal Importation Channel, Fort Collins: Provided preliminary and final design of 1.5 miles of a major drainage channel sized to intercept flood flows that overtop two large canals. Performed hydraulic floodplain analysis and delineation. Provided final design of two major street crossings, including a double 4-foot by 19-foot, 3-sided, precast box bridge; a double 4-foot by 8-foot, precast box culvert; three riprap drop structures; a concrete baffled chute flume crossing of a canal; a large architecturally designed concrete drop inlet into a box culvert; a dual siphon of a storm sewer under an existing canal; and, relocation of a major 30-ineh water transmission main. Prepared construction drawings, specifications, and cost estimates for contractor bidding. Piney Creek and Tributaries Stream Stabilization and Major Crossing Planning: Conceptual and preliminary design of alternatives to provide stream stabilization and floodplain improvements for 17.4 miles of drainageway in Arapahoe County. Work items included preparation and review of hydrologic information: determination of the 100-year floodplain; identification of existing and potential stream bed erosion: development of alternative improvements; benefit-cost analysis; reclamation of best plans; preliminary design; and, cost estimates for proposed improvements. Total cost of proposed improvements exceeded $20 million. Upper Goldsmith Gulch, Greenwood Village: Preliminary and final design of approximately 2,000 feet of major drainageway through the Denver Technological Center in Greenwood Village. Final design included a grasslined irrigation park-like channel with a concrete low flow and architecturally designed drop structure. Channel designs also included a natural grasslined channel with a "soft" low flow bottom used for mitigation of wetland habitat, including a natural boulder drop strncture. Design included completing a wetland mitigation plan for obtaining a 404 Permit. Also required was protection of the existing <SO-inch and 54-inch raw water line for the City of Aurora. Final floodplain analysis was completed for a CLOMR/LOMR submittal to the City. Broomfield and Vicinity Outfall Systems Planning, Broomfield, CO. Assisted in drainage Master Planning for 25 square miles of rapidly urbanizing area between the cities of Bo~lder and Denver, Colorado. An integrated master drainage and flood control plan was prepared for the entire planning area which included six major drainageways, nine tributary drainageways, and numerous outfalls and storm sewers. The hydrologic and hydraulic analyses performed provided the basis for proposing alternative planning and preliminary design solutions for existing drainage problems as well as those problems anticipated with the rapid growth in the area. Special considerations in the project included major on-stream detention facilities to mitigate existing downstream flooding problems in developed areas, cost analyses, and integrated of all the planned facilities with other existing and proposed improvements within the basin. 27