Stormwater Engineer in Eugene: Infiltration Tests & Drainage Design
A jurisdiction asks for an infiltration test, or a stormwater facility, or a plan that shows where the water goes — and the owner needs an engineer to answer. Johnson Broderick Engineering is a stormwater engineer in Eugene that handles both the testing and the design, for single lots and full commercial sites.
What we do
- Stormwater infiltration testing — we can perform the infiltration test for your property and use the results in the design
- Stormwater facility design — sized to the site and to the jurisdiction’s requirements
- Drywells
- Rain gardens
- Bioswales
- Storage systems and retention ponds
- Drainage systems for homes, commercial sites and industrial sites
- Connections to city systems — designing how new site drainage ties into an existing municipal stormwater and sewer system
A question we get often
“Can you assist with performing a stormwater infiltration test and designing a stormwater facility for my property?” It’s one of the ten questions we’re asked most on a first call. Yes, we can.
Stormwater on a commercial site
On the new Dave’s Hot Chicken on Mohawk Boulevard in Springfield, our civil design included stormwater retention ponds alongside the parking, drive-through and circulation. During construction we worked with the contractor on site on the unforeseen issues where the new civil design met the City of Springfield’s existing stormwater and sewer system. The restaurant opened on time in the summer of 2025. Read the project.
Stormwater on a residential lot
A new house, addition, ADU, shop or driveway adds hard surface, and many jurisdictions want to know where that water will go. We can design the drywell, rain garden or other facility, and the drainage around it, as part of the permit package — on its own, or together with the structural engineering for the building.
Common questions
Do I need an infiltration test?
It depends on your jurisdiction and your project. If your permit reviewer or planner has asked for one, send us their comment and we’ll tell you what it takes.
Can you design the drainage as well as the building?
Yes. We are civil and structural engineers, so the stormwater design and the structural design can come from the same office on the same schedule.
What does it cost?
We bill time and materials against a deposit, generally $2,500 to $3,500 for a new project. Once the scope is clear we give you a fee estimate before any extra work, and unused deposit is refunded — which happens often.
Related projects
Veneta Food Truck Plaza Dining Hall
Veneta: Repairing rot-damaged floor framing and permitting an older wood-framed building in phases so it can serve as indoor dining for a food truck plaza.
Siletz Tribal Office Remodel
Eugene: Permit drawings to reclad, re-window and update an office building for the Confederated Tribes of Siletz Indians, approved by the City in under three weeks.
Hayward Field – Finish Line Truss
Eugene: a ballasted, guyed anchorage for the finish line truss inside Hayward Field for the 2025 Eugene Marathon — no anchors into the ground.
Coos Bay Hall Building – Egress Stair
Coos Bay: a new five-floor steel egress stair tower for the 1928 Hall Building, on drilled piles through about 100 feet of bay mud to bedrock.
Market of Choice Loading Dock Canopy
Eugene: A steel moment-frame expansion of a grocery store’s loading dock canopy, designed for snow drift and joined to the existing structure, completed in 2020.
Lane Events Center Roof Deck Repair
Eugene: during the Lane Events Center reroof, we assessed rust-damaged steel roof deck and designed in-kind replacement details that kept the project moving.