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Western Dam Engineering Technical Note 17 base his bid assumptions and (2) design his required components. Generally, this is accomplished by including available information in bid documents provided to the contractor in what’s known as a baseline report. A baseline report may include geotechnical data reports, flood hydrology reports, annual streamflow records, descriptions of on-site and off-site materials, and identification of areas available for contractor use. 3.Information to be Verified by the Contractor In some cases, the information needed for the development of contractor designed components may not be available prior to construction, and it may be left to the contractor’s discretion to obtain the necessary information. In these cases, it should be explicitly stated within the specifications that it is the contractor’s responsibility to verify conditions. This may require them to perform additional investigations, such as subsurface exploration or camera inspections of outlets. 4.Submittal Process and Review Times When provisioning for contractor-designed items, sufficient lead time must be allocated in the schedule for any required investigations by the contractor, the design development (including analyses, shop drawings, and specifications), submittal review, and fabrication. All contractor design submittals should be stamped by a registered professional engineer, preferably registered in the state where the project is being completed. Review and approval of these design components may also involve third parties, such as regulatory agencies, which will take additional time. The engineer’s review and approval of these components generally constitutes acceptance of the contractor’s plan but does not relieve the contractor, or his designer, of the professional responsibility for their effectiveness. Examples of Where Team Effort Specifications Might Be Used Effectively These are some typical components in which the result or performance requirement of the component is known, but there is generally some flexibility regarding the means and methods that can be used to achieve the desired result. In these cases, the component can be designed by the contractor, within the specified criteria, and reviewed and accepted by the engineer. When deciding whether these components are best designed by the contractor after award, or ahead of time by the engineer, one should consider the relative sensitivity of the component in terms of potential impact to quality and schedule of work, as well as the relative dam safety risk if the contractor’s method proves inadequate or inefficient. As a general rule of thumb, a contractor’s design, which is being cost-competitively bid, is usually more aggressive (less conservative) than if it were pre- designed by the engineer of record. 1.River Diversion – A diversion plan for dealing with river or watershed flows is generally necessary to limit the potential for site flooding and to allow the contractor to complete the work in the dry. Diversion systems will generally consist of a cofferdam designed to withstand a particular flood event of a given frequency (e.g., 25-year flood), which is related to the expected construction period and the consequences of failure. This may include channels, conduits, chutes, tunnels, or flumes around the work area to pass flows around the work site. For projects where the primary risk of failure of the diversion system is to the contractor’s completed work or to his equipment and work areas, it may be beneficial to allow the contractor to determine his own level of risk tolerance, within appropriate limits. Consider allowing the contractor to include as a bid item one “clean-up” following an abnormally high flood event, with “abnormally high” being well- defined in the specification. The definition should be clear to limit the allowance only to natural events that would endanger the contractor’s work area but not pose a risk to the dam in its fragile state. This approach of “sharing the risk” removes a level of contractor uncertainty. When uncertainty is reduced, bid prices are normally lower. In cases where significant normal stream flows exist and/or where risks to population and development downstream of the work area are present, it is usually prudent for the engineer to design the river diversion requirements in advance, avoiding team-effort specifications.