Location: Lacey, WA
Owner: Washington State Department of Transportation
Construction Bid Opening Date: August 22, 2018
OCI designed the stormwater and temporary sediment and erosion control elements for this WSDOT Design-Bid-Build project located at the I-5/SR 510 (Marvin Road) interchange in the City of Lacey. The project will upgrade the existing interchange to a Diverging Diamond Interchange (DDI) and add a southbound frontage road to accommodate future growth in the area. The proposed DDI is the first of its kind in the State of Washington, and as such it presented several unique challenges. As the drainage lead for the project, OCI implemented several flow control and water quality best management practice (BMP) designs to minimize downstream impacts of runoff from new pavement areas. These design elements included six infiltration ponds, five bioswales for runoff treatment, 9,000 linear feet of storm drain and several ditch conveyance systems. OCI maximized the use of on-site BMP systems at the interchange within existing right-of-way limits through the evaluation of existing soil and groundwater conditions. This has been an exciting project to design for the State of Washington and we look forward to seeing it constructed!
The DDI design is proven to improve safety by reducing conflict points, decrease wait times at signals, and increase traffic flow. Construction is scheduled to begin in the fall of 2018 and be completed in 2020.
For more information about WSDOT’s I-5/SR 510 DDI Project, click here, and for more information about the DDI design concept, click here.
Conceptual image courtesy of WSDOT
Photo courtesy of WSDOT

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.