Location: Seattle, WA
Owner: Washington State Department of Transportation
OCI was under contract with HNTB, part of Seattle Tunnel Partners, and developed site specific and construction phase specific TESC Plans and Narrative for the project. Major areas of concern for erosion and sediment transport on this project were the south and north portals, particularly the cut and cover section of the tunnel which involved pile construction, deep excavations, and concrete handling activities associated with viaduct demolition, muck transport, and emergency storage.
OCI completed the engineering analysis needed to obtain the NPDES Construction Stormwater General Permit and the King County Wastewater Discharge Authorization for the project. OCI determined temporary and permanent discharge locations and designed connections to the existing drainage systems. In order to determine discharge capacity of existing outfalls, a backwater analysis for outfall pipes from the regulator discharging to Elliott Bay at the south portal area was conducted. MGSFlood and SBUH design software were used to determine the maximum stormwater flows and volumes expected from the south and north portals based on the maximum footprint of construction activities. This information was then used to determine temporary storage tanks and treatment plant size required to meet discharge standards.
OCI coordinated with the geotechnical engineer for dewatering volumes and assisted in reviewing compliance plans for discharge volumes and water quality. This project involved coordination with the Contractor, design-build permitting team, and various stakeholders on the project such as Seattle Public Utilities, King County, City of Seattle, WSDOT, and Port of Seattle.
OCI worked as an extension of the HNTB drainage design team and assisted with stormwater design and calculations. OCI’s engineers performed QC of the stormwater report and plans.
Service Details >>
- Stormwater Management and Design
- Stormwater Detention, Infiltration, and Treatment Design
- Hydrologic and Hydraulic Modeling
- Stormwater Pollution Prevention Plan (SWPPP) and Narrative
- Temporary Erosion and Sediment Control (TESC) Plans
- Green Streets and On-Site Stormwater Management Approaches
- Bridge Scour Analysis
- Highway Runoff Dilution and Loading Stormwater (HI-RUN) Model
- Culvert Analysis and Design
Deepa leads Osborn Consulting’s Transportation Drainage practice and brings experience focused on surface water engineering and modeling. Deepa has worked on several design build (WSDOT and Sound Transit) and local agency stormwater projects. Her main focus has been on transportation drainage design, hydrologic and hydraulic modeling and analysis, neighborhood drainage improvements, stormwater planning and design projects including project ranking and prioritization, temporary erosion and sediment control design, environmental compliance involving permit coordination, compliance regulation (NPDES and Sewer Discharge Permits), and field inspections. Deepa has excellent record of meeting client schedules and completing work with a high degree of accuracy and competence. She is currently the co-chair for the ASCE Seattle Section Water Resources Committee.
OCI Shareholder and Board Member
Joined OCI: 2008
Education: MS in Environmental Systems Engineering, University of Regina
Licenses and Certifications: PE in Washington State, Certified Erosion and Sediment Control Lead (CESCL), WSDOT Highway Runoff Manual (HRM) Trained, WSDOT Fish Passage and Stream Restoration Design Training
Associations: ASCE, WTS
HOBBIES & INTERESTS
Deepa likes to spend her free time catching up on TV shows and movies. She enjoys a good masala Bollywood movie any day. Originally from the southern part of India, Deepa loves travelling and visiting places, listening to her daughter talk non-stop about football or any other sports for that matter, and craves spicy food from any cuisine.