1 <br />GEPPER Jeffrey A <br />From:Eric Favreau <favreaueng@gmail.com> <br />Sent:Thursday, October 24, 2024 6:21 PM <br />To:SINGER Doug K; Dane Butler; WALCH Therese; Admin; GEPPER Jeffrey A <br />Subject:Re: Stormwater - Crescent Village Docs <br />[EXTERNAL ❚❛❜] <br />Hi Doug, <br /> <br />Thanks again for taking the time to chat about the concerns with the draft stormwater code update. I really <br />appreciate the effort to make sure this update will be thoroughly vetted. <br /> <br />Per our conversation, I am requesting that the following language be submitted as public testimony: <br /> <br />Regarding the draft language of EC 9.6792(3)(b)(1)(a) which proposes to reduce the minimum infiltration rate <br />for an infiltration facility from 2 inches per hour to 0.6 inches per hour, I have concerns about how this <br />language will be implemented. I believe it is poor design practice for an infiltration facility with low infiltration <br />rates (less than 1 inch per hour) to not have some form of drainage system to prevent standing water. An <br />example of this would be a perforated underdrain, similar to what is found in a typical filtration facility. My <br />worry is that for facilities that fall within that 0.6-1 inch per hour infiltration rate, that these facilities will have <br />to be designed as infiltration facilities and won't be able to have an underdrain installed in them. My <br />recommendation would be to keep the original 2 inch per hour threshold now that the draft language in EC <br />9.6792(3)(b)(2) requires extended filtration facilities, which still allow for infiltration, but also have an <br />underdrain system to ensure that stormwater doesn't perpetually stay in the facility. <br /> <br />One thing that I'm just now thinking about is that the draft language in EC9.6792(3)(b)(2) doesn't allow for an <br />exception to the extended filtration facility requirements if a geotechnical analysis determines that the soils would <br />be unsuitable and unsafe for a surface facility. Perhaps I'm missing that somewhere else though. What do you <br />think? <br /> <br />Thanks, <br /> <br />Eric Favreau PE <br />Favreau Engineering <br />(541) 556-4425 <br />favreaueng@gmail.com <br />From: SINGER Doug K <DSinger@eugene-or.gov> <br />Sent: Thursday, October 24, 2024 3:42 PM <br />To: Dane Butler <dane@butlerhomes.net>; WALCH Therese <TWalch@eugene-or.gov>; Eric Favereau 2206 Country <br />Haven <favreaueng@gmail.com>; Admin <admin@wobuildersassoc.com>; GEPPER Jeffrey A <jgepper@eugene-or.gov> <br />Subject: RE: Stormwater - Crescent Village Docs <br /> <br />Dane, <br />You verbally indicated today that you intend this email including the attachments to be submitted as Public <br />Testimony to the Eugene Planning Commission. We will submit this information unless we hear otherwise. <br /> <br />Doug Singer, PE, CSM <br />Development Services Manager <br />Principal Civil Engineer