LEI evaluated existing site drainage conditions and then designed a stormwater drainage system that provides the existing water treatment and conveyance for the entire site for the Oregon Department of Transportation Right-of-Way. The site is a 2.83 acre commercial development in the City of Springfield consisting of a hotel, parking lot, pedestrian facilities and landscaping.
LEI followed the City of Springfield Engineering Design Standards. The City of Portland Stormwater Management Manual (BES) governed water quality standards. Moreover, the water quality demand flows had to be treated before entering the public stormwater facilities. This required LEI to use both vegetated swales and water quality catch basins. The entire stormwater system for the site provided conveyance for at a minimum, the 25-year storm event.
LEI also developed erosion and sedimentation control plans for the project site. We also provided a stormwater drainage report, which consisted of runoff calculations, pipe sizing calculations, conceptual drawings and design drawings. LEI developed erosion control and sedimentation control plans for the 1200C DEQ permit. In addition, we completed grading design, sanitary sewer design and waterline design along with approved building permits for construction.