HomeMy WebLinkAboutSWG Letters / Memos - 9/19/2022 September 19' , 2022
Attention: Scott Ruedy
Mason County, Washington
Community Development Department
615 Alder St.
Shelton, WA 98584
RE: Union Washington Residences
SU: On-site Sewage System Repair—SEPA Exemption
Dear Scott:
The community on-site sewage system (OSS) in Union,Washington, serving the
following parcel numbers(only parcels involving proposed repair work are included):
322335000007
322336000009
322335000010
322335000011
322335000012
322335000901
322335000902
322335000904
has been found to have several OSS tanks that leak groundwater into them during the
"rainy season", causing excessive flows to the community drainfield. Although the
drainfield has not been found to be failing (as determined from investigations by myself
and Eric Knopf[O&M Operator for this OSS] in March of 2021), having excessive"I&I°
flows(groundwater infiltration and surface water inflow, or"infiltration& inflow") can lead
to pre-mature drainfield failure. In addition,the cover soils over the drainfield that were
used during installation were found to be very poor, retaining excessive moisture and
causing saturated or spongy ground, potentially inhibiting oxygen transfer to the
drainfield trenches, inhibiting OSS drainfield maintenance, and inhibiting general use.
As a result of these issues, a repair project is proposed for the community OSS. This
repair project includes replacing all septic tanks and pump tanks that serve building on
the parcels listed above with new tanks and also replacing the cover soil over the
drainfield with a sandier soil with better drainage characteristics. Some piping
replacement will also be necessary.
This OSS repair project is only replacing OSS components that have been found to have
inadequate performance. The project does not expand the OSS in any way(i.e. no new
building or bedrooms are being added; no increase in permitted design flow).
Regarding the State Environmental Protection Act(SEPA), it is my understanding that
this repair project of an existing sewer utility should be categorically exempt from SEPA
according to Washington Administrative Code(WAC) 197-11-800, Section (3) Repair,
remodeling, and maintenance activities (see following page):
Aqueem Solutions Engineering,PLLC Ph:(360)3184704 Em: mike.moren75Qgmail.rom
P.O.Box 1635
Bellingham, WA 98117 Page I oft
3a 2 33 6D 00610
Hood Canal—Union Properties
On-site Sewage System Repair—SEPA Exemption
September 19°,2022
"Repair, remodeling and maintenance activities. The following activities shall be
categorically exempt: The repair, remodeling, maintenance, or minor alteration of
existing private or public structures, facilities or eguioment. including utilities.
recreation, and transportation facilities involving no material expansions or
changes in use beyond that previously existing,except that, where undertaken
wholly or in part on lands covered by water, only minor repair or replacement of
structures may be exempt(examples include repair or replacement of piling,
ramps, floats, or mooring buoys, or minor repair, alteration, or maintenance of
docks)."
Final grades of the tank and drainfield cover soil replacements are to match existing
grades, and therefore no net increase in material expansions are proposed. In addition,
none of the proposed OSS infrastructure to be replaced is located on land wholly or
partially covered by water. Although several of the parcels are waterfront parcels, none
of the work is below Mean Higher High Water(MHHW)or Ordinary High Water(OHW).
Please contact me via phone(360)318-4704, or e-mail mike.moren75(&gmail.00m
should you have any additional comments or questions.
Sincerely, G.,S,P� 0�.�c�
Mike Moren, P.E. ,6 9119 43079
Aqueous Solutions Engineering, PLLC t ,o
�LWgAL
Aqueoas Soludons Engineering,PLLC P.O.Box 1635 Bellingham,WA 99227
(360)3184704
mike.momn756r mail.com Page 2 of