HomeMy WebLinkAboutRR-11 PRE2022-00031 WRITTEN NARRATIVECA received 08/15/25
EXHIBIT RR11
CA received 08/15/25
EXHIBIT RR11
CA received 08/15/25
EXHIBIT RR11
CA received 08/15/25
EXHIBIT RR11
Septic System Components
Septic Tank: ≥1,500 gal two-compartment State-approved septic tank; with two 24"-diameter access risers
above inlet and outlet, extending up to-grade, equipped with lids, bonded to rings integral to tank. Tank to be
equipped with influent baffle/drop tube and outlet drop tube and rigid effluent filter with 1/16 " orifice size.
Suggested effluent filter: Clarus Environmental WW1 (Zoeller Pumps) Effluent Filter Part No. 170-0078.
Gravity-Flow Transport Pipelines: 4-inch PVC ASTM D-3034 sloped 2% (¼ inch per ft) from proposed
source(s) to septic tank. 4-inch PVC ASTM D-3034 from septic tank to distribution box, sloped as needed. Pipe
runs equipped with long-sweep clean-outs, positioned as needed, secured at surface for expected >30-year
lifetime.
Distribution Box: Plastic or Concrete D-Box with at least seven effluent connections at the same elevation.
Unit bedded with pea gravel. Effluent connections equipped with speed-levelers. D-Box equipped with riser,
equipped with secured lid.
Gravity Drainfield: Seven 3-ft wide x 41-ft long gravel trenches, installed horizontally, with infiltrative surface
approximately 19 to 27 -inches below ground surface. One 4"-diameter perforated PVC distribution lateral per
trench, fitted with long-sweep sanitary tee at the distal end, with slip cap, not glued, to serve both as lateral end
clean-out and infiltrative surface inspection port. 4-inch PVC upswept lateral ends shall be end-sawed to loosen
connection with end caps , to prevent caps from sticking. Distal ends installed within ≥6"-diameter cylindrical
utility vaults (or equivalent) extending 1-2" above grade, capped, secured and marked.
Construction Notes
Septic System Layout: The septic system designer must supervise layout of the system prior to excavating . Laser leveling
or similarly precise systems must be used for leveling, to ensure precisely horizontal infiltrative surfaces .
Septic Tank Placement: The tank excavation must have a horizontal bottom prior to adding bedding material. Six inches
(6") of pea gravel bedding must be provided to properly support tank in order for tank warranty to remain effective . If shallow
groundwater is encountered during tank installation , a newly-installed tank should be filled with water to prevent floating , in
case groundwater rises around it. Tank must be covered with a 1-ft minimum thickness compacted soil, or structural fill, to a
maximum cover of 3-ft, unless a heavy load-rated tank is used.
Risers: Access risers should be installed above septic tank openings. Risers and lids should extend 2 to 3 inches above
grade to help prevent debris from falling into risers upon opening. Tank access risers shall be bonded to integral rings built
into tank openings, using 3M™ Marine 5200 Adhesive Sealant, or equal, or better.
Monitoring Ports: Future septic system inspections will be simplified with properly-installed monitoring ports at key points
in the drainfield, at least two per lateral. Monitoring ports should extend down to the bottom of the drain rock layer , no
deeper than 27 inches below the pre-disturbance ground surface. Monitoring ports must be installed during drainfield
construction and prior to covering. They must be anchored by any of several means, in order to maintain their stability for
several decades. Using wood or other biodegradable materials is not recommended for anchoring/stabilizing systems.
Sheet 1 of 4. Residential Septic System Description and Construction Notes
Property Owners: Richard D . & Renee F. Rathvon
660 Twana Way; Quilcene , WA 98376
Jefferson County Parcel Number 701164005 Parcel Area: 5.47 acres (238,000 ft2)
Conventional Gravity-Discharge to Gravel Trenches
Drinking Water Source: Proposed Water Well; Location TBD
Proposed Septic System Capacity: 5-BR, 600 gal/day peak flow (average ≤450 gpd)
Soil Types 3 & 4; Application Rate : 0.7 gal/ft2/day
Minimum Infiltrative Surface Area: 600 gpd/0.7 gpd /ft2 = 860 ft2
No indicators of seasonally-shallow ground water down to ≥63" below ground surface
Designed By:
Everett A. Sorensen, P.E.
Evergreen Engineering Services
715 Grant Street
Port Townsend, WA 98368-2405
ev_sorensen@hotmail.com
360-821-9960
July 18 , 2022
Sheet Index:
1. Description and Construction Notes
2. Site Plan
3. Septic Tank Details
4. Drainfield Distribution Trench Details
CA received 08/15/25
EXHIBIT RR11
Potential
Building
Site
Drawn By:
Everett A. Sorensen, P.E.
Evergreen Engineering Services
715 Grant Street
Port Townsend, WA 98368-2405
ev_sorensen@hotmail.com
360-821-9960
July 18 , 2022; Revised September 15 , 2022
Proposed Drainfield: Seven
48 -ft x 3-ft Trenches Provide
1,000 ft2 of Infiltrative Surface
Note: Trenches may curve to
follow elevation contours
Sheet 2 of 4
Overall Site Plan with Proposed Septic System Layout
Rathvon Property
660 Twana Way; Quilcene , WA 98376
County Parcel 701164005
5.47 Acres (238,000 SF)
S3S1
S2S4
S6
S7 S8
S9
Note: Pending water well must be located greater than
100 ft from drainfield. All other water system components
must be at least 10 ft from all septic system components
Proposed 1,500-gal septic tank
Proposed >4,500 SF
Reserve Area
Proposed 7-Outlet D-Box
Original Scale: 1 inch = 80 ft
0 160 240 Ft80
Proposed 4-inch Sewer
Background LIDAR & Contours
from Jefferson County on-line GIS 230'Parcel BoundaryS5
CA received 08/15/25
EXHIBIT RR11
≥1,500 gal Two-Compartment Septic Tank
Approved Concrete or Polyethylene Tank
Secure Lids
4-inch diameter gravity-drain from
wastewater source, sloped 2% (Typically
ASTM 3034 standard PVC sewer piping
with integral bell and gasket)
Optional Clean-out finished above grade with
threaded plug set in 4"x18 "x18 " concrete pad
(or equivalent stabilized installation)
Sanitary Tee
Typical accumulated solids
Typical accumulated floating mat
3" Min. Sep.
Effluent Outlet
12 " Min. Sep.
Sheet 3 of 4
Proposed Septic Tank Cross-Section
Proposed Septic System
Rathvon Property
660 Twana Way
Quilcene , WA 98376
County Parcel 701164005
5.47 Acres (238,000 SF)
6"-8" thick pea gravel bedding
Horizontal Excavation
Septic Tank Installation Requirements:
6 inches of pea gravel shall be spread on horizontal compacted
excavation bottom before placing tank , level, on pea gravel
Tank risers shall be bonded to ring integral to tank with 3M™
Marine 5200 Adhesive Sealant, or equal, or better, and grouted on
the outside of the joint,
Excavation Extent
Maximum solids accumulation
prior to pump-out
Drawn By:
Everett A. Sorensen, P.E.
Evergreen Engineering Services
715 Grant Street
Port Townsend, WA 98368-2405
ev _sorensen@hotmail.com
360-821-9960
July 18 , 2022
Tank Inlet ≥16"
below grade
Inlet Drop-Tube
(or baffle)
Effluent Drop-Tube
To D-Box
Ground Surface
Access risers extending 1 to 2 inches
above-grade bonded to integral tank ring
Ring Integral
to Tank
Sewage Entry
Optional 4" Thin wall-to-thick
wall adapter (needed to adapt
typical tank drop tube assembly
to schedule 40 PVC)
Compartment 1Comp. 2
Dividing Baffle
Removable effluent filter screen with 1/16 " max. mesh size installed within
effluent drop tube . Recommended
model: Clarus (Zoeller) 170-0078
Septic Tank Effluent Filter
Grout around
inlet pipe
Grout around outlet pipe
CA received 08/15/25
EXHIBIT RR11
PVC cap, not glued
4" slotted PVC
Horizontal Trench Bottom, less than
1 inch elevation variation over length
Trench Cross-Section, Side View
Not-To-Scale
Coarse drain rock
Backfilled Soil Cover
Undisturbed Soil
Not-To-Scale
2" to 3" Stub-Up
Filter fabric above drain rock
½-inch orifices spaced
12" apart, off-center
Secure Lid10" min. cylindrical utility vault
Trench Depth
≤27"
Sanitary Tee Doubles as
Lateral Clean-Out and
Infiltrative Surface
Inspection Port
Drawn By:
Everett A. Sorensen, P.E.
Evergreen Engineering Services
715 Grant Street
Port Townsend, WA 98368-2405
ev _sorensen@hotmail.com
360-821-9960
July 18 , 2022
Sheet 4 of 4
Drainfield Distribution
Trench Cross-Section
Proposed Septic System
Rathvon Property
660 Twana Way; Quilcene , WA 98376
County Parcel 701164005
5.47 Acres (238,000 SF)
3 ft minimum
Trench Cross-Section
End View
Not-To-Scale
4" slotted
PVC
6" minimum cover
Drain
Rock
Filter fabric above gravel
Finished grade directs
drainage away from trench
Backfilled Soil Cover
Finished Surface; Vegetation Restored
Undisturbed
Soil
Undisturbed Soil
Undisturbed
Soil2" minimum
6" minimum
Pre-Disturbance Ground Surface
Minimum 6" sidewall
into native material
27-inch Trench
Depth at High Side
CA received 08/15/25
EXHIBIT RR11