Northwest Watersheds LLC

Reuniting Communities and Nature

About the firm

Northwest Watersheds LLC (NWW) is a civil and water resources engineering practice founded in 2019 and based in Portland, Oregon. NWW delivers stormwater management design, stream restoration, flood studies, fish passage engineering, and water quality monitoring for municipalities, state transportation agencies, and federal clients across the Pacific Northwest and beyond.

Established: 2019
Team: Micro
Firm type: Civil Engineering · Environmental Engineering

People

Mary LarkinPrincipal Engineer

Stephen BlantonPrincipal Engineer

Capabilities

Stormwater Management Design

Service website

Engineering design for stormwater conveyance and management facilities serving transportation corridors, urban developments, parks, and industrial sites.

Green Street Design
Regional Stormwater Facilities
Plans, Specifications & Estimates
Hydrologic & Hydraulic Modeling
Design Services During Construction

Water Resources Planning

Service website

Planning services to help clients meet regulatory obligations, improve stormwater system performance, and address capacity needs driven by growth and flooding.

Stormwater Master Planning
Stormwater Retrofit Evaluations
Grant Support
Water Quality Studies

Stream Restoration

Service website

Analysis and design to address stream instabilities caused by hydromodification and land use changes, restoring natural flow processes and sediment transport to degraded stream corridors.

Field Investigations
Hydrologic Monitoring
1D & 2D Hydraulic Modeling
Sediment Transport Assessment & Stable Channel Design
Permitting Support
Design & Construction Services

Hydraulic Structures & Fish Passage Design

Service website

Assessment and engineering design to correct fish passage barriers and restore natural function to stream corridors, addressing all life stages.

Geomorphologic Assessment
Sediment Transport Modeling
1D/2D Hydrologic & Hydraulic Modeling
Hydraulic Reports
Engineered Logjam & Fish Passable Culvert Design
Bank Protection & Stream Stabilization
Design-Build Support

Flood Studies

Service website

Hydrologic and hydraulic modeling and floodplain mapping to support projects within FEMA regulatory boundaries, including CLOMR and LOMR documentation.

Hydrologic Modeling (HEC-HMS, SWMM, HSPF)
1D & 2D HEC-RAS Modeling
SRH-2D Modeling
Floodplain & Floodway Mapping
CLOMR/LOMR Documentation

Water Quality Monitoring

Service website

Stormwater and stream monitoring programs designed to meet permit requirements, including equipment selection, installation, sampling, and reporting.

Stream Gage Installation
Automated Sampler Selection & Installation
Instream Flow Monitoring
Stormwater Sampling
Water Quality Technical Reports
Data Validation & QAQC

Industries

Stormwater & Flood Control · Water Resources · Environmental & Remediation · Transportation · Natural Resources

Projects

Kruger Creek Stream Stabilization

Environmental & Remediation

Project details

NWW led geomorphic assessment and stream stabilization design to address hydromodification in Kruger Creek. Work included hydrologic modeling using the Tualatin River Urban Stormwater Tool (TRUST) and HEC-RAS hydraulic modeling to support stormwater bypass and diversion structure design. Deliverables include plans, specifications, and a cost estimate for stream enhancement measures ranging from engineered wood placement to rock-lined channel sections adjacent to slumping landslides.

SR 167 Completion Project

Fife, WA · Transportation · Client: Washington State Department of Transportation

Project details

Stormwater design for a two-mile WSDOT highway facility connecting the I-5/SR 167 interchange with SR 509 near Fife, Washington. NWW developed conveyance, flow control, and water quality treatment designs including three constructed wetlands, eleven swales, and six bioretention facilities discharging to the Hylebos riparian restoration floodplain. Hydraulic reports were prepared to meet WSDOT and Washington State Department of Ecology standards, with the project advancing through design-build delivery.

WSDOT Olympic Region Fish Passage - Burley Creek

Gig Harbor, WA · Natural Resources · Client: Washington State Department of Transportation

Project details

Preliminary hydraulic reports for three fish passage barrier culverts on Burley Creek and its tributaries under State Route 16, near Gig Harbor, Washington. NWW conducted site visits to evaluate geomorphic, riparian, and hydraulic conditions, collected field data on sediment size, and performed SRH-2D hydraulic modeling to support new crossing design in coordination with agency and tribal stakeholders.

Columbia Slope Stormwater Retrofit

Vancouver, WA · Stormwater & Flood Control

Project details

Identification, screening, ranking, and design of stormwater retrofit facilities throughout the Columbia Slope watershed in Vancouver, Washington. NWW participated in field investigations evaluating opportunities including regional stormwater facilities, green street retrofits, and modifications to existing infrastructure, then provided grant application support and concept designs for the highest-ranked projects.