Stormwater Management & Drainage Improvements

Our stormwater management and drainage project experience includes regional flow control and water quality facilities, comprehensive and master plans, basin studies, stream enhancement and restoration projects, facilities needs assessment and corrective actions plans, facilities inventories, operations and maintenance manuals, industrial site developments, residential drainage designs, roadway and parking lot drainage designs, permitting assistance, and regulatory compliance.

We offer our clients a variety of the most up-to-date computer stormwater models to best fit their needs. We maintain knowledge of stormwater and environmental regulations and requirements so that we may be a resource to communities as they plan for the future. DCG also offers expertise in areas such as agency stormwater management and enforcement, including plan reviews and inspections. DCG has numerous Certified Erosion and Sediment Control Lead (CESCL) staff members.


4th Ave S and S Trenton St Storm Drainage Improvements - Seattle, Washington

4th Ave S and S Trenton St Storm Drainage Improvements

The $3.6 million improvements included over 3,700 lineal feet of new ductile iron storm drains ranging from 12″ to 24″ in diameter with a variety of catch basin and inlet types to provide the most efficient collection of stormwater. DCG modeled the area’s storm drainage system in XP-SWMM by utilizing the model from the Preliminary Engineering phase to confirm storm drain sizing under two scenarios: 1) with tidal influence and 2) without tidal influence.

DCG utilized the WSDOT continuous gutter calculations spreadsheet/method to optimize catch basin and inlet spacing and locations. The joint Seattle Public Utilities/Seattle Parks project also included water quality swales within a previously unimproved park site, grading and pathways for the 3.5 acre park, and construction phase engineering support, and worked closely with the landscape architecture sub-consultant and Parks staff to integrate the stormwater improvements within an aesthetic park setting.


Yauger Park Phase 1 Storm Drainage Improvements - Olympia, Washington

Yauger Park Phase 1 Storm Drainage Improvements

DCG was selected by the City of Olympia to assist in the proposed expansion of a joint-use recreation and stormwater flow control facility.

The project goals and site constraints included factors such as maintaining use of ball fields, trails and other recreation facilities, expanding available detention volume, improved water quality facilities, providing public parking, and improving maintenance access to stormwater facilities at the park.

DCG worked with the Public Works Department as well as Parks staff to define several conceptual approaches, identify parking alternatives, and calculate additional stormwater detention volume and preliminary construction costs for each approach.


On-Call Drainage Services - Whidbey Island, Washington

On-Call Drainage Services

DCG was selected by Island County Public Works to provide on-call storm drainage consulting services and has been tasked with the completion of more than 26 projects ranging from AutoCAD drafting services to design and construction phase support. The projects have included a variety of High Density Polyethylene (HDPE) pipes installed down steep bluffs, anchoring systems, HDPE diffuser tee outfalls, bubble-up dissipater vaults, and horizontal bore culvert replacements.

The projects typically involve coordinating and corresponding with property owners, county staff, WDFW staff, surveyors, geotechnical engineers and contractors. DCG has completed basin modeling, facility sizing, system design, engineer’s estimates, construction drawings, construction phase support, and project closeout services.