When the City of Delaware set out to increase sanitary sewer capacity for future development and improve service reliability for neighborhoods near Pennsylvania Avenue, the City partnered with B&N to evaluate long term solutions for a critical wastewater corridor. The East Olentangy Sewer Interceptor Study focuses on an 8,100 foot route extending from the city neighborhoods to the wastewater treatment plant headworks, an area with shallow rock, narrow rights of way and multiple Olentangy River crossings.
B&N’s Role
B&N is leading the technical evaluation of conveyance alternatives, integrating hydraulic modeling, GIS based alignment analysis and field verification to help the City determine a resilient, cost effective and long term solution. Our team is also assessing constructability challenges and regulatory considerations that influence alignment and technology selection.
Project Approach
The study evaluates two primary alternatives:
- 60 inch gravity trunk sewer
- New pump station (26,100 GPM / 37.6 MGD) with a 36 inch forcemain
To support transparent decision making, B&N developed a weighted criteria matrix and applied advanced modeling tools, ArcGIS Pro for route analysis and PCSWMM for system modeling under existing, 2035 and full build out scenarios. Field crews completed multi month flow monitoring to understand system performance during varying weather and soil conditions.
Given the corridor’s complexity, several alignments are under review. One potential alignment traverses open space and parkland and requires four river crossings likely to involve microtunneling to reduce surface disruption and maintain environmental protection.
Key Features & Innovations
- Advanced GIS based alignment screening
- Multi scenario hydraulic modeling to plan for long term growth
- Field verified wet weather data to improve model accuracy
- Evaluation of microtunneling for deep, environmentally sensitive crossings
Anticipated Outcomes
The feasibility study will provide the city with a clear, comparative roadmap for future investment, supporting growth to the north, reducing reliance on an aging trunk sewer along US 23 and improving service reliability for residents. Design and construction are expected to follow over the next several years.