Off-Site Analysis. Xxxxxxx will conduct a downstream analysis extending ¼ mile downstream/down-gradient of the project right-of-way limits for each of the Threshold Discharge Areas (TDAs) identified. The downstream analysis will include a review of City GIS maps, recent drainage complaint documentation provided by the City (if it exists), and a visual assessment of downstream routes to identify evidence of erosion, flooding, sedimentation, or flow constriction points. A visual above-ground inspection, where practical, will be conducted for each of the downstream drainage conveyance systems associated with the project. Representative photographs will be taken and an assessment of the downstream effects will be performed. The assessment of the downstream effects is to be a qualitative evaluation based upon engineering judgment. Xxxxxxx will prepare a written description of the downstream system conditions and provide a map showing downstream routes. Xxxxxxx will perform a visual inspection of the upstream contributing basin area of the site and provide an estimate of the area draining to the site based on available mapping data and site visit observation. Should more than one (1) downstream analysis be required, the Consultant will inform the City and a contract supplement will be prepared if necessary. A detailed review of upstream basin boundary or land use assessment and any detailed hydraulic analysis or computations associated with the upstream or downstream basins is not included. Any necessary access onto private property will be coordinated by the City. The City will provide the Consultant with a copy of documented drainage complaints in the project area and within the downstream vicinity. The Consultant will use this information to help assess the onsite and offsite drainage system. Deliverables: • Off-site analysis write-up and associated map: To be included in the drainage report
Off-Site Analysis. The Consultant will conduct a downstream analysis extending ¼ mile downstream/down-gradient of the project limits. The downstream analysis will include a review of recent drainage complaint documentation provided by the City (if it exists) and a visual assessment of the downstream route to identify evidence of erosion, flooding, sedimentation, or flow constriction points. A visual above-ground inspection, where practical, will be conducted for the downstream drainage conveyance system associated with the project. Representative photographs will be taken, and an assessment of the downstream effects will be performed. The assessment of the downstream effects is to be a qualitative evaluation based upon engineering judgment. The Consultant will prepare a written description of the downstream system conditions and provide a map showing downstream routes. This task does not include detailed hydraulic analysis or computations of the downstream section, but it can be provided as an additional service. The Consultant will perform a visual inspection of the upstream contributing basin area of the site and provide an estimate of the area draining to the site based on available mapping data and site visit observation. This task does not include a detailed review of upstream basin boundary or land use assessment and any detailed hydraulic analysis or computations associated with the upstream basin, but it can be provided as an additional service.
