HomeMy WebLinkAbout2021-09-14_Ockert_(MH) LO stormwater_middle housing_ From: fanfh-carole(aleurooa.com
To: randvarthur7Calamail.com
Cc: bobandmianonacomcast.net;Olson.Erik
Subject: (MH)LO stormwater/middle housing?
Date: Tuesday,September 14,2021 5:31:58 PM
To:Chair Arthur:
Re: Stormwater,Middle Housing Committee Key Issue#3 Memo
On the agenda for the upcoming Middle Housing Committee Sept. 15th meeting
is Stormwater,Questions and Answers and Deliberations.In order to have
substantive deliberations on the details of the amount of impervious
surfaces on a lot and the subsequent impacts,the committee needs a
functional understanding of how stormwater and development currently works
within Lake Oswego's framework.
Looking to the Key Issue#3 Stormwater Memo for understanding,I read:
"The stormwater code requires that new developments and all development
projects over a certain size manage all stormwater on the lot...."
I brought this issue forward in my email dated August 17th,2001 that is
posted on the MH website.
see link:
httns://www.ci.osweeo.or.us/WebLink/DocView.asnx?id=1 g60136&dbid=0&reno=CitvOfLakeOsweao
The statement that new developments manage all stormwater on the lot does
not seem to follow the reality of a new build in FANFH that was examined
and approved by staff. Staff has said:
"With respect to the specific situation you are referring to,I'll just
quickly point
out that those pipes are part of the design of stormwater facilities to
generally
ensure that post-development runoff rates do not exceed pre-development
runoff
rates;one of these pipes manages stormwater discharge from the lot,and
the other
is an emergency overflow for when the facility is clogged.The owner is
generally
responsible for making sure the facility operates correctly and are
required to sign
a maintenance agreement which runs with the land."
I went with the new build's stormwater report in hand to a local soils
geologist.What I learned was that the stormwater on this site in FANFH is
being treated onsite during a small rain event,but NOT managed onsite.To
state that water is being managed onsite requires the water to go back
into the soils onsite.In this new build in progress,the water is being
treated by being filtered through gravel,sand and plantings in a
completely enclosed cement cistern adjacent to the full basement of the
home,and then it is discharged into a gully that slopes down into Tryon
Creek.For the basic physics,think swimming pool with a drain into a
gully that slopes into Tryon Creek.There is no design in the system that
allows for the water to infiltrate into the onsite soils.In the event of
prolonged heavy rains and the cement cistern having reached capacity,the
water directly releases through a pipe into the gully without any
stormwater treatment at all,to avoid spilling over the top of the
cistern on to the home site.
I am not looking for us to rework our stormwater code.What I am saying
is,as we look to siting middle housing,duplexes,triplexes,quadplexes,
townhomes and cottage clusters on heretofore single family lots,the
Middle Housing Committee must have an accurate understanding of how our
stormwater regulations currently direct the size of infill development in
Lake Oswego and how our city staff interpret and implement those
stormwater regulations.If our current stormwater regulations only require
stormwater be treated onsite and permit all discharge offsite,then we
need to know that because we need to plan for potential impact to
surrounding properties.Or we need to write stronger building code,
understanding that our stormwater code is not going to hold water.
Thank you.
Carole Ockert
Below is a copy of an email I have sent to Ryan Lentz in the Engineering
Dept.to get specific answers.
Hi Ryan,
I have a 2 very simple questions:
1.I have had a geologist review the system design for stormwater for 977
9th and have been informed that the system does not infiltrate any water
into the site at all.Can you confirm that as designed this particular
cement cistern system does not infiltrate any stormwater into the site?
2.If this lot had no access to the gully,would you have allowed the same
sized development to be built on the site?
Thanks,
Carole
Carole Ockert,
FANFH Land Use Liaison and
Middle Housing Citizen Advisory Committee representative from the
Neighborhood Chairs Committee