From stormwater design to site plans and permits, we can get it done.

Impact Design served as project manager to coordinate the permitting, civil engineering and stormwater system design of a 42 unit senior housing apartment building expansion for the Parkview West Apartments in Lynden, WA. Impact Design presented the proposal to the Lynden City Planning Commission and Lynden City Council. The project is currently under construction.

Impact Design provided civil engineering and landscape architectural design on a new showroom & maintenance facility in Ferndale, WA.  This new 12,000 sf steel building along with four other storage buildings were constructed on a 3 acres development and contained parking improvements, utility connections and an underground stormwater detention pump system to meet stormwater detention and treatment requirements. Construction was completed Summer of 2022.

Impact Design has provided engineering and permitting support for over 60 culvert replacements for the Sudden Valley Community Association (SVCA) since 2019. These projects have ranged in size from small maintenance actions to medium sized culvert replacements to full box culvert fish passage crossing projects. Below is a description of four selected efforts.
2020 Sudden Valley Culvert Replacements
Impact Design provided engineering and permitting support for (5) culvert replacements in the Sudden Valley Development in Whatcom County. Fish passage standards applied to several of these culverts. Impact Design worked closely with Saturna, WDFW, Whatcom County Planning Department, Army Corps of Engineers, and other parties to successfully permit the culvert replacements. PowerTek also completed the topographic and boundary survey for this project.
SRSC Programmatic Permit with Whatcom County
Impact Design was able to secure an interlocal agreement and programmatic permit with the Whatcom County Public Works Department allowing for long-term maintenance actions to be completed without the need for individual Land Disturbance Permits or the SEPA process for each project. Months of time and tens of thousands of dollars in consultant and permit fees are now saved on future projects as many maintenance actions are now outright permitted through Whatcom County. This will provide substantial time and financial savings for SRSC while this programmatic permit is active and will structure the success of the 10-year Capital Improvements Plan.

The NW Fish Passage and Impact Design Team prepared a temporary stream diversion plan for the E. Smith Rd Pavement Rehabilitation Project. Our team prepared and provided a technical review for a Stream Diversion Plan for Granite on a very short timeline. The NW Fish Passage Team completed an analysis of flow through the proposed pipe and informed Granite on minimum pipe size. Construction was completed Summer of 2021.

Impact Design provided the civil engineering and stormwater system design of a single family residence on the shores of Lake Samish including support for a shorelines permit and land disturbance permit with Whatcom County Planning and Development. Construction was completed in 2021.

Impact Design provided the required civil engineering and stormwater design plans, specifications and report to permit a condominium development on Front Street in Lynden, WA. This project required the coordination with the City of Lynden and a third party engineering review firm to complete the requirements of the City and the Washington State Department of Ecology. The project is currently under construction.

Impact Design served as project manager to provide emergency assistance to the Grandview Industrial Park to replace a failing culvert during a flood event in the winter of 2020. Within two weeks, Impact Design had submitted the required engineering plans, calculations and permits to WSDOT and received a permit to replace the failing permit. Impact Design worked with Stormwater Solutions NW to ensure that no property damage was done to the nearby Kona Bike warehouse.

Impact Design, Certerra and Canyon Environmental provided an alternative analysis, comprehensive design and support services for Whatcom County’s Eagleridge Stormwater Improvements project, including developing construction documents for proposed facilities to improve phosphorus removal and water quality treatment associated with the Eagleridge subdivision. The project involves installing five Filterra stormwater treatment units, modifying existing drainage infrastructure, performing roadway and sidewalk improvements, and restoring disturbed areas. The scope included project management, environmental permitting support, property rights and utility coordination, and preparation of stormwater design reports and phased design deliverables (30%, 60%, 90%, and final PS&E documents), all compliant with applicable county and state standards. Deliverables include plans, specifications, cost estimates, and technical reports. The design phase of the project is scheduled to be completed in May 2026.

The Greenbank Farm Fire Pond Restoration Project for the Port of Coupeville involves comprehensive pond rehabilitation including dredging approximately 1,195 cubic yards of sediment, regrading pond slopes, installing sediment management infrastructure, and stabilizing banks with erosion control measures. Impact Design provided civil engineering design and permitting support through a phased approach—developing three alternative design concepts addressing sedimentation, bank erosion, eutrophication, and water quality concerns, followed by preparation of construction drawings, stormwater management reports, and Island County permitting documentation. The project includes the installation of a large sediment trap with bypass valves, slope stabilization using quarry spalls and amended soil, and jute matting with native plantings to prevent future erosion. This restoration enhances both fire suppression capacity while implementing long‑term maintenance improvements for the Greenbank Farm facility.

The CityGate Multifamily Development in Lynden involved comprehensive civil engineering design and stormwater management for a multifamily housing project at the intersection of 19th and Front Streets. Impact Design provided surveying, civil engineering, landscape architecture, and permitting support, developing construction drawings, stormwater management reports, and hydraulic calculations for 53,382 square feet of new impervious surface including buildings, parking, and sidewalks. The project utilized WWHM 2012 hydrologic modeling to design a complete infiltration system using rock infiltration chambers with engineered sand filter media to meet enhanced treatment requirements, eliminating surface discharge and achieving 100% on‑site stormwater management. The design incorporated BMP T5.13 soil quality standards, pretreatment using a Contech CDS unit, and comprehensive SEPA documentation to satisfy all nine minimum requirements of the 2019 Washington State Department of Ecology Stormwater Management Manual, demonstrating expertise in low‑impact development and regulatory compliance for urban infill projects.

Impact Design prepared construction documents and stormwater report for the Spring Road Centralized Phosphorus Treatment System in Sudden Valley to help the community meet Whatcom County stormwater compliance requirements. The project installed a 4×8 MWS‑Linear Modular Wetland unit at the base of an existing drainage course to treat runoff from a 3.42‑acre basin of roadway, roofs, landscaping, and native vegetation. Using WWHM 2012 hydrologic modeling, hydraulic capacity analysis, and the unit’s Ecology‑approved 50 percent phosphorus‑removal efficiency, the system provides a treatment flow capacity of 0.115 cfs and mitigates up to 1.49 acres (≈64,900 SF) of roadway. The project demonstrates Impact Design’s expertise in hydrologic and hydraulic modeling, pollutant loading and nutrient‑reduction analysis, and GIS‑based basin delineation and site evaluation, ensuring precise sizing of treatment facilities and defensible regulatory compliance. This centralized facility offset Sudden Valley’s phosphorus‑mitigation deficit and supports future pavement repairs on Spring Road and Green Hill Road, providing long‑term, code‑compliant water‑quality improvement within the Lake Whatcom watershed.