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e e e By maintaining a conservative approach to estimating materials and cost as well as design, a certain amount of inefficiency is introduced to the project. However, with good judgement based on experience, such inefficiencies can be minimized. Permitting Permitting was viewed as a critical path task. The permits required by this project included 404 dredge and fill to be obtained from the U.S. Army Corps of Engineers (COE), floodway development from the City and County of Denver, and construction stormwater quality from the cities of Aurora and Denver and the State of Colorado. The 404 permit was viewed as having the longest lead time and was addressed as work in progress before the contract was executed. Fortunately, the individual permit issued in Phase I could be extended to include the proposed Phase III improvements even though the 3-year monitoring period had ended. This extension required notification of the COE regarding a request for extension. The submittal required for this request included a description of the proposed work; presentation of wetlands, threatened and endangered and cultural resources surveys; and restoration and mitigation plans. The repermitting process consisted of a pre-application conference, request for extension submittal, 30-day notification, review and comment period, and issuance of requirements and conditions. The proposed work was found to affect 0.15 acres of jurisdictional wetlands. Mitigation of this impact included: . Restoration of river edge wetlands consisting of cottonwoods, willows, shrubs and native grasses. . Creation of a wetlands associated with the Aurora wastewater reuse plant effluent outfall. This wetland, comprising approximately 0.5 acres, includes a backwater basin fed by the treated wastewater effluent, groundwater, and backwater flow from the stream. The permit process lasted approximately two months from the time of the application submittal to issuance of an extension. This time period included submittal, preparation of notice by the COE, a 30-day comment period, and preparation and issuance of permit conditions. The floodway development permit process was much more lengthy. Floodplain modeling indicated that proposed conditions would not have an adverse impact on 1 OO-year flood elevations, and that the bankfull condition in most cross sections exceeded the 10-year flow. Adverse impact on 100-year flood elevations was interpreted to mean any rise in the elevation between the regulatory model and the proposed model. City and County of Denver regulations were interpreted to allow stream channel improvements in the floodway as long as there is no adverse impact to flood elevations. The proposed conditions model predicted at most cross sections that the 1 OO-year water surface elevation will be lower than those predicted by the regulatory model. This was due primarily to increasing channel conveyance by regrading the vertical cutbanks to a much flatter slope and widening the streambed. Several conditions had to be met before the floOdplain permit could be issued: . A pre-application meeting was held with staff from Denver's Wastewater Management Division (WWMD) and the Urban Drainage and Flood Control District (UDFCD). . Hydraulic modeling had to be completed including duplicating the regulatory model, updating the regulatory model to present conditions and running it, and modifying the present conditions model to include proposed improvements. . Development and submittal of the application. . Response to comments received on the application.