Stormwater Management Design. This task includes design and preparation of documents for the stormwater management designs. Prepare the stormwater drainage plans and show stormwater drainage profiles on the roadway profile sheets. Prepare cross-section and access details for surface treatment/infiltration facilities, as needed. Prepare the storm drainage details. Drainage plans to be included as shown in the Design Plan List and Subtasks 14.11, 14.12, 14.13, and 14.14.
Stormwater Management Design. This task includes design and preparation of reports and construction documents for the 30%, 60%, 90%, and final submittals. Consultant shall provide a stormwater management report outlining the stormwater management design for each design milestone: 30%, 60%, 90%, and final. For the report, Consultant shall use data and information collected from available mapping, site visits, and other available methods. The stormwater management report shall provide: • A discussion of the testing results of existing underground injection controls (UICs) in the project area, summarizing the factors of safety and the recommended design infiltration rates. • A summary of the proposed stormwater management design confirming adherence to the City and DEQ requirements. • A basin map showing onsite and offsite basin areas requiring stormwater management. • Spread and conveyance calculations for the proposed stormwater conveyance system • Analysis and sizing of UICs • Assessment of utility conflicts and proposed required relocations or adjustments. • Research and complete process for abandonment of existing drill holes, as needed. Assumptions: • Stormwater design shall be according to the current City requirements as well as the Central Oregon Stormwater Manual (COSM). • 1200-C permit is required. • Consultant shall assist City in preparing necessary State DEQ permits if any existing drywells are recommended to be removed / decommissioned. • The area is conducive to infiltration and UICs are the preferred stormwater infrastructure. Vegetated facilities shall be proposed where adequate space within right of way is available.
Subtask 10.1.2 Deliverables:
Stormwater Management Design. This task includes design and preparation of reports and construction documents for the 30%, 60%, 90%, and final submittals. Contractor shall provide a stormwater management report outlining the stormwater management design for each design milestone: 30%, 60%, 90%, and final. For the report, Contractor shall use data and information collected from available mapping, site visits, and other available methods. The stormwater management report shall provide: ▪ A discussion of the testing results of existing underground injection controls (UICs) in the project area, summarizing the factors of safety and the recommended design infiltration rates ▪ A summary of the proposed stormwater management design confirming adherence to the City and DEQ requirements. ▪ A basin map showing onsite and offsite basin areas requiring stormwater management. ▪ Spread and conveyance calculations for the proposed stormwater conveyance system ▪ Analysis and sizing of sedimentation manholes and UICs ▪ Assessment of utility conflicts and proposed required relocations or adjustments. ▪ Research and complete process for abandonment of existing drill holes, as needed. ▪ The area is conducive to infiltration and UICs are the preferred stormwater infrastructure. Vegetated facilities will be proposed where adequate space within right of way is available.
Stormwater Management Design. This task includes updating the Phase 1 Stormwater Report to reflect the key routes design and stormwater management. Assumptions: • Stormwater design shall be according to the current City requirements as well as the Central Oregon Stormwater Manual (COSM). • Phase 1 1200-C permit will cover Phase 2. • Drainage from the multi-use path will sheet flow and infiltrate into the existing ground or into rock galleries as needed.
Stormwater Management Design. Evaluate the prior design basins and infiltration pond sizing and infiltration results from construction of the roundabout. Based upon proposed roundabout upgrades, evaluate existing catch basin locations, and needed relocations to accommodate roundabout upgrades. Provide new drainage basins for the new roundabout configuration and catch basins. Model the existing pond based utilizing topographic survey data and infiltration data. Provide recommendations to pond sizing revisions as needed. Memorialize in a concept drainage report (CDR). Prepare plans sheets based upon the outcomes. Consultant shall prepare the following storm drain plan and profile sheets:
a. General grading and basin calculation sheets
b. Storm drain details limited to City standards and/or surface treatment/disposal facilities
c. Storm drain plan and profile sheets.
d. Plan and section sheets for pond revisions. • Designs and calculations based upon City design and construction standards and the COSM. • Existing conditions will be based upon as constructed drawings, inspection reports, and topographic survey. • Prepare a Concept Drainage Report per City of Bend design standards. • 30% storm drainage plans and estimate to be submitted under task 5.4.
