Laserfiche WebLink
Exhibit A (Scope of Work) <br />•Problem Statement: Clearly define the problem or question the model aims to address (e.g., flood risk <br />assessment, water distribution analysis). <br />•Geographic Area: Specify the location and extent of the area being modeled <br />•We assume the hydrologic model performed for the Surface Water Comprehensive Plan does not <br />need to be updated, flows will be extracted from the existing, and worse -case future, conditions; <br />however, if development in the basin requires updating the hydrologic modelling, Otak would request <br />a contract amendment <br />•Model Type: SRH - 2D steady state <br />•Hydraulic analyses will extend from Mukilteo Boulevard to the 3000 feet downstream to outfall in Port <br />Garnder Bay; to assess potential impacts off the project such as flooding, channel erosion or <br />deposition, or impacts to critical habitat <br />•Otak will set up an existing conditions plan, and one proposed condition plan to support preliminary <br />design; if iterations are needed to refine the proposed conditions, that would be covered under a <br />contract amendment <br />•Otak will provide preliminary hydraulic results such as scour depth water flow depth, shear stress, <br />velocity to Everett for use in streambed and structure low chord design <br />•Otak has budgeted up to 24 hours to coordinate with the City on how to utilize the hydraulic results for <br />design <br />•Normal depth boundary condition will use hydraulic modeling <br />•The preliminary design included in this task will be assessing an average slope/hydraulic condition <br />with the culvert and immediately upstream and downstream of the culvert. We anticipate that during <br />the 60% design, the habitat features and geomorphic plane form or stream type(s) such as cascading <br />boulders and/or step-pools will be added in the culvert, as well as upstream and downstream of the <br />culvert. The habitat features may include a deformable bed design, to support in culvert meander <br />bars and the installation of habitat features such as woody structures and boulders. Refinement of <br />the preliminary hydraulic model to support the 60% design is not included in our scope and fee; Otak <br />can add this as an amendment if needed, or the City can update the mode l <br />TASK 5.1 DELIVERABLES <br />•Fish Passage Basis of Design Memorandum which includes: <br />o Key Findings: Summarize the key findings of the modeling study. <br />o Visualization: Present the model results in a clear and concise manner (e.g., maps, tables, <br />graphs). <br />o Interpretation: Interpret the model results and their implications for the problem being <br />addressed. <br />5.2 Alternatives Analysis <br />Two culvert alternatives will be prepared to compare culvert structure type for the culvert replacement. <br />OTAK will evaluate suitable foundation types for the culvert(s) based on the geotechnical investigation. <br />The pros and cons of each alternative will be provided with a comparison table, and a recommendation <br />for a preferred alternative. The comparison table will include culvert capital construction costs, potential <br />utility conflicts and relocation, public safety, construction challenges, maintenance consid erations and <br />ease of permitting. In addition to the comparison table the design criteria and any expected variances <br />and 10% concept drawings will be documented in an alternatives analysis technical memorandum.