Stormwater Treatment for Hotel Development


A development company needed Farallon’s help to meet the stormwater treatment requirements of multiple regulatory agencies.

When planned hotel construction stalled because of the presence of 0.08 acre of wetlands on the site, Farallon designed a stormwater treatment system and submitted a Stormwater Management Plan that complied with multiple regulatory requirements, allowing the client to resume pursuit of the necessary development permits.

In 2006, the U.S. Army Corps of Engineers authorized filling 9.5 acres of wetland for a development that included the Site and adjacent properties. However, only 9.42 acres of wetland were filled at that time.  As part of the authorization, a stormwater treatment facility was constructed, which met standards at the time of its construction but not the requirements in place in 2017. Due to changed requirements, the additional 0.08 acre of fill could not be authorized until current stormwater treatment standards were met. Farallon designed new stormwater treatment facilities to be used in conjunction with the existing facility to provide water treatment in accordance with the current requirements of the U.S. Department of Commerce National Oceanic and Atmospheric Administration National Marine Fisheries Standard Local Operating Procedures for Endangered Species, the Oregon Department of Environmental Quality 401 Certification Post-Construction Stormwater Management Plan, and city stormwater treatment design standards. 

“We were able to come up with a design that easily fit into the developer’s plan while meeting various regulatory requirements and incorporating an existing yet insufficient treatment facility,” said Senior Engineer Matt Hillyard, who provided technical support for the project.  “Farallon’s justification and supporting calculations for the use of the existing development’s stormwater treatment facility to address flow-reduction requirements was a significant benefit for the developers, who had already designed the 1.43-acre hotel development on a space-limited parcel without any flow-reduction facilities.”