HomeMy WebLinkAbout2018.03.20 - David Cohn Wetland Delineation Rating and Habitat Impact Report for 3057 7th Street
David Cohn
Wetland Delineation, Rating
And Habitat Impact Report:
New Farmhouse and Septic System
March 20, 2018
Prepared for:
David Cohn
3057 7th Street
Port Townsend, WA. 98368
Site Address:
3057 7th Street
Port Townsend, WA. 98368
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 2 | M S A
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 3 | M S A
Contents
I. Introduction ................................................................................................................................. 4
II. General Site Conditions ............................................................................................................. 5
III. Site Information ........................................................................................................................ 5
Soil Survey .................................................................................................................................. 5
National Wetlands Inventory ...................................................................................................... 6
IV. Wetland Assessment Methods .................................................................................................. 7
V. Wetland Delineation ................................................................................................................. 8
Wetland 1 (Figure 7) ................................................................................................................... 9
Wetland 2 (Figure 8) ................................................................................................................. 12
VI. Wetland Rating ....................................................................................................................... 14
Wetland 1 – Rated Category IV – Buffer of 40 Feet (Figure 7) ............................................... 16
Wetland 2 – Rated Category IV – Buffer of 40 Feet (Figure 8) ............................................... 16
Wetland 3 – Rated Category 1V – Buffer of 60 Feet (Figure 9) .............................................. 16
Wetland 4 – Unrated at Property Owners Request – Buffer of 350 Feet (Figure 10) .............. 17
VII. Proposed Site Restoration/Developmental Changes ............................................................. 17
Existing Farm House Removal ................................................................................................. 18
Construction of replacement farmhouse ................................................................................... 20
Decommission of Existing Septic System ................................................................................ 23
Installation of New Septic System ............................................................................................ 24
IIX Summary ................................................................................................................................ 27
IX. References.............................................................................................................................. 29
X. Figures ...................................................................................................................................... 30
Figure 1. Site and Vicinity Map ................................................................................................ 30
Figure 2. National Wetland Inventory (NWI) Map .................................................................. 31
Figure 3. NRCS Soil Survey ..................................................................................................... 32
Figure 4. Vegetation Line Between Upland and Wetland ........................................................ 33
Figure 5. Layout of Proposed Plan for New Farmhouse .......................................................... 34
Figure 6. Proposed Farmhouse Design for City of Port Townsend .......................................... 35
Figure 7. Wetland 1................................................................................................................... 36
Figure 8. Wetland 2................................................................................................................... 37
Figure 9. Wetland 3................................................................................................................... 38
Figure 10. Wetland 4................................................................................................................. 39
XI. Appendix: Rating Images, Data Forms .................................................................................. 40
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 4 | M S A
I. Introduction
Marine Surveys & Assessments (MSA) was authorized by the applicant and property owner,
David Cohn, to assess four wetland areas over ten parcels, located within the municipal
jurisdictions of Jefferson County, Washington and the City of Port Townsend, Washington.
These ten parcels equal approximately 77.0 acres. Parcel numbers 001093002, 001093001,
997000101, 997000201, and 997000701 fall within Port Townsend city limits; parcels
001093004, 997000301, 997000601, 997000401, and 997000501 fall outside Port Townsend city
limits. All parcels are located in the SW 1/4 SEC 9, T30N, R1W (Figure 1).
For ease of identification, the wetland areas within these parcels are designated 1-4 (Figure1) and
will be referred to by these identifying numbers thoughout this report; wetlands 1-3 lie within the
limits of the City of Port Townsend, and wetland 4 lies just outside city limits and is governed by
Jefferson County statutes. Wetland 1 and 2 were both delineated, rated, and assigned buffers;
Wetland 3 was rated and assigned a buffer; Wetland 4 was mapped and assigned a buffer.
Wetlands 1-3 were assigned buffers based on City of Port Townsend code; wetland 4 was
assigned a buffer based on Jefferson County code.
As part of an effort to restore environmental value and function to these parcels after a long
history of agricultural use, several developmental changes have been proposed. These changes,
which are listed below, are addressed in regards to the impacts to the four wetlands found on the
property, both short- and long-term, as well as mitigation recommendations to minimize those
impacts.
1. Removing the current farmhouse, which is located within the buffer of wetland 2;
2. Construction a replacement for the current farmhouse outside the buffer of any onsite
wetland, in the footprint of the original, historic farmhouse
3. Replacing the septic field of the current farmhouse, which is located within the buffer of
wetland 2;
4. Installing a replacement for the current septic field outside the buffer of any onsite
wetland
5. Restoring the hydrologic continuity between wetlands 2 and 3 by restoring flow under the
access road in the topographical low corridor, as opposed to the artificial current routing;
6. Removing invasive, nonnative vegetation species from wetland 1 and 2, and restoring
native aquatic wetland species;
7. Improving habitat continuity for native grazers and predators by removing relic barbed-
wire across the total acreage.
Each aspect of the above restoration has been assessed for impact on current habitat value and
function.
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 5 | M S A
II. General Site Conditions
This property is mostly open farmland located within a relatively residential and developed
section of east Jefferson County [zoned R-II(SF) - Medium Density Single-Family] on Quimper
Peninsula. It is west-southwest of Port Townsend, WA by approximately 2.4 miles, and west-
northwest of Port Hadlock, WA by approximately 5.0 miles. The property is 77.0 acres and is
divided into ten parcels, the vast majority of which is open, having been logged and farmed years
ago. There is a small farmhouse in the central-western section of the property, along with a small
outbuilding and large barn, accessed from the east via 7th Street, off Discovery Road (Figure 1).
To the north, the property is bordered by forested land, while the west and southwest is bordered
by residential neighborhoods, accessed in large part from South Jacob Miller Road. To the east is
Discovery Road, a major town artery. Generally, the elevation along the northern section of the
property is greater than the southern; drainage on the property flows from north-to-south. The
western quarter, approximately, consists of a wetland corridor running from the northwest corner
of the property southeast to the man-made pond on the southern border.
Four wetland areas were identified on the property. The smallest (Wetland 1) is approximately
0.10 miles northwest from the farmhouse; the next largest in size (Wetland 2) is almost
immediately adjacent to the farmhouse to the northeast; to the southeast by approximately 0.07
miles lies the next largest wetland (Wetland 3), while the largest, being the aforementioned
northwest-southeast corridor in the western quarter of the property (Wetland 4), is approximately
0.33 miles west of the farmhouse (Figure 1).
The property was, during its time as a working farm, sectioned into seven pastures by wooden
fence-posts and barbed-wire fence, all of which are accessed by the driveway, which extended
into a rough jeep-track traveling east-west almost the width of the property. As a result of
widespread cattle grazing, the vegetation over most of the property’s open area is greatly
homogenous, dominated by common agricultural/disturbed area grasses: Agrostis capillaris,
Dactylis glomerata, and Phalaris arundinacea. The western section of the property, close to
Wetland 4, is distinguished by a gradual shift to scrub-shrub forest from fallow agricultural
fields.
III. Site Information
Soil Survey
Soil
Symbol
Soil Name Acres
CfC Cassolary sandy loam, 0 to 15 percent slopes .2
CmC Clallam gravelly sandy loam, 0 to 15 percent slopes 59.7
DaC Dabob very gravelly sandy loam, 0 to 15 percent slopes 2.3
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 6 | M S A
DcC Dick loamy sand, 0 to 15 percent slopes .1
HuC Hoypus gravelly loamy sand, 0 to 15 percent slopes 14.5
StB Swantown gravelly sandy loam, 0 to 8 percent slopes 3.6
*Figure 3
National Wetlands Inventory
The USFWS NWI map (on the National Wetlands Inventory website) shows 4 mapped wetlands
and 1 mapped pond within the 77 acres of property (Figure 2). Three of the wetlands are
classified by the NWI according to the Cowardin classification system as Palustrine Emergent
Shallow Marsh Semi-Permanently Flooded (PEMF) and the remaining wetland as Palustrine
Emergent Shallow Persistent Scrub-Shrub Seasonally Flooded (PEM1/SSC). National Wetland
Inventory code interpretations are as follows:
• P: System Palustrine: includes all non-tidal wetlands dominated by trees, shrubs,
emergents, mosses or lichens, and all such wetlands that occur in tidal areas where
salinity due to ocean derived salts is below 0.5 ppt. Wetlands lacking such vegetation are
also included if they exhibit all of the following characteristics: 1. are less than 8 hectares
( 20 acres ); 2. do not have an active wave-formed or bedrock shoreline feature; 3. have at
low water a depth less than 2 meters (6.6 feet) in the deepest part of the basin; 4. have a
salinity due to ocean-derived salts of less than 0.5 ppt.
• EM: Class Emergent Wetland: characterized by erect, rooted, herbaceous hydrophytes,
excluding mosses and lichens. This vegetation is present for most of the growing season
in most years. These wetlands are usually dominated by perennial plants. All water
regimes are included except subtidal and irregularly-exposed.
• F: Water Regime Semi-Permanently Flooded: surface water persists throughout the
growing season in most years. When surface water is absent, the water table is usually at
or very near the land surface.
• 1: Subclass Persistent: Dominated by species that normally remain standing until the
beginning of the next growing season. This subclass is found only in the Estuarine and
Palustrine systems.
• SS: Class Scrub-Shrub: Includes areas dominated by woody vegetation less than 6m (20
feet) tall. The species includes shrubs, saplings, and trees of stunted growth form dues to
environmental conditions.
• C: Water Regime Seasonally Flooded: Surface water is present for extended periods
especially early in the growing season, but is absent by the end of the growing season in
most years. The water table after flooding ceases is variable, extending from saturated at
the surface to a water table well below the surface.
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 7 | M S A
The NWI map documents were prepared primarily by stereoscopic analysis of high altitude
aerial photographs taken in 1980 and 1981. Wetlands were identified on the photographs based
on vegetation, visible hydrology, and geography. The aerial photographs typically reflected
conditions during a specific year and season when they were taken. Some small wetlands and
those obscured by dense forest cover may not be included on the map. In addition, there is a
margin of error inherent in the use of aerial photographs. As you will see in our delineation
results, the actual Cowardin classification of the wetlands found differed from those on the
USFWS NWI map.
IV. Wetland Assessment Methods
Consistent with procedures detailed in the Washington State Wetlands Identification and
Delineation Manual (Washington State Department of Ecology, 2011 Manual), preliminary
information was gathered on the project site prior to the field review, rating and delineation.
General information sources included:
• 1974 National Wetland Inventory (NWI) maps, United States Fish and Wildlife Service
(USFWS)
• 1975 Soil Survey of Jefferson County Area, Washington (USDA)
• 2013 Washington Department of Natural Resources Water Resource Map (DNR)
• 1979 Washington State Wetlands Identification and Delineation Manual, (WSDE)
• 2009 Jefferson County Unified Development Code Chapter 18.22 Critical Areas
Jefferson County Critical Areas Map
• 2014 State of Washington 2014 Wetland Plant List US Army Corps of Engineers (COE)
• 2014 Washington State Wetland Rating System for Western Washington 2014 Update.
(Hruby, T Washington State Department of Ecology)
Field delineations followed the methodology outlined in the Regional Supplement to the Corps of
Engineers Wetland Delineation Manual (effective January 1987): Western Mountains, Valleys
and Coast Region 9 Version 2.0) U.S. Army Corps of Engineers. This is standard manual, used
in determining wetland areas when applying state and local government regulations under the
Shoreline Management Act and the Growth Management Act in Washington State.
Field ratings followed the methodology outlines in the Washington State Wetland Rating System
for Western Washington; 2014 Update field manual, published by the State of Washington
Department of Ecology. The specified buffers, identified in accordance with each individual
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wetland’s rating score, are specified in Jefferson County Code, Table 18.22.330(3), Wetland
Categories, Rating Scores and Buffer Widths.
The extent and location of all four wetlands were determined during field work completed during
August 11th – 22nd, 2016. Field work was done under variable conditions with an ambient
temperature ranging between 66° and 80° Fahrenheit. The time of year and recent precipitation
history were considered in assessing the extent of the suspect wetlands presumed to exist on site.
Specific field methodology used in determining the extent and location of wetland areas include:
1) As part of the initial project site reconnaissance, the site was walked to determine the
general extent and location of potential wetland areas.
2) Wetland and upland sample plots were established in the identified potential wetland
areas and in the adjacent upland areas; and
3) The extent of the wetlands was located with a GPS unit and measured on the ground to
reference points.
V. Wetland Delineation
Wetland delineation establishes the existence (location) and physical limits (size) of a wetland
for the purposes of federal, state, and local regulations. In determining these physical parameters
of each individual wetland, indicators of vegetation, soils, and hydrology are analyzed to assess
critical areas. By defining the transition zone between scientifically established upland and
wetland indicators, an established accurate boundary of the wetland can be identified between a
pair of data points; one representing the upland and one representing the wetland. It is common
for paired data points, when linked to vegetative indicators (such as an obvious transition line of
upland grass into an emergent herbaceous community), to inform the identification of the
wetland delineation. A delineation, often in conjunction with a subsequent rating, is a necessary
procedural step in obtaining information which will inform subsequent construction.
Of the four wetlands found on the property, two were delineated. Wetland 1 and 2 were
delineated for reasons of potential future construction; the property owners identified these
locations as potential building spots, and therefore opted to obtain more accurate wetland
boundaries. Wetland 1 and 2, both classified by the US Fish and Wildlife National Wetlands
Inventory as PEMF (Semi-permanently Flooded, Palustrine, Emergent Marsh), were delineated
using standard paired wetland test plots. Wetland 1, which was smaller and more homogeneous
of border, was delineated using two paired test plots. Wetland 2, which was slightly larger and
more heterogeneous of border, was delineated using four paired test plots.
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Each test plot consisted of two data points, designated “Dry” and “Wet”. Each data point
consisted of a test pit dug to standard depth of 16 inches, to expose a representative soil profile.
Each data point was then assessed for the presence of three wetland indicators: hydrophytic
vegetation, hydric soils, and wetland hydrology. Following the successful location of paired data
points, flagging was hung between data points to mark the wetland boundary. The test pits at
each data point were marked with yellow flagging, pink wire flags, and GPS latitude and
longitude was taken.
Wetland 1 (Figure 7)
Paired Data Point GPS Co-ordinates:
Plot A – Wet: 48.10667N 122.81567W
Plot A – Dry: 48.10673N 122.81582W
Plot B – Wet: 48.10660N 122.81542W
Plot B – Dry: 48.10664N 122.81528W
1. Vegetation
In an effort to distinguish the types of plants that grow in different hydrologic regimes, the U.S.
Fish and Wildlife Service incorporated a system of wetland plant indicator status to classify
individual plant species. The wetland indicator status of a species is based on the individual
species occurrence in wetlands in 13 separate regions within the United States. A plant indicator
status is applied to the species as a whole; however individual variations exist within the species.
Indicator categories are as follows:
OBL – obligate wetland – Almost always occurs in wetlands under natural conditions.
FACW – Facultative Wetland – Usually occurs in wetlands, occasionally found in uplands.
FAC – Facultative – Equally likely to occur in wetlands or non-wetlands
FACU – Facultative Upland – Usually occurs in non-wetlands, occasionally found in wetlands.
UPL – Obligate Upland – Almost always occurs in uplands under natural conditions.
To meet the qualification as a site dominated by hydrophytic vegetation, wetland plant species
must show at least one of five hydrophytic vegetation indicators (Appendix A; Data Forms). All
test plots that qualified as wet sites did so by fulfilling the same wetland vegetation indicator: all
dominant species across all strata are either classified as OBL or FACW.
The wetland boundary for this depressional wetland was directly correlated to a visible
vegetation line between upland and wetland species (Figure 4); this is visible on satellite imagery
and was supported by observations in the field. As the land is primarily of old agricultural use
and therefore disturbed over a long period of time, the biodiversity was considerably less than
would be found in a similar depressional wetland in a natural state. As there were no woody
vines present at the test plots, cover estimates were made within a 5-foot and 30-foot diameter
circle for the herbaceous and shrub/tree strata, respectively.
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 10 | M S A
Due to limited biodiversity in a long-term agriculturally disturbed landscape and the
consequent redundancy of plant species, test plots are combined below.
Wetland 1 – Sample Plot A and B – Wet: Vegetation
Stratum Common Name Latin Name Status
Herb Soft Rush Juncus effusus FACW
Herb Reed Canarygrass Phalaris arundinacea FACW
In both wetland test plots, hydric vegetation was present (Appendix A; Data Forms).
Wetland 1 – Sample Plot A and B – Dry: Vegetation
Stratum Common Name Latin Name Status
Tree Scouler’s Willow Salix scouleriana FAC
Herb Orchard Grass Dactylis glomerata FACU
Herb Colonial Bentgrass Agrostis capillaris FACU
Herb Bracken Fern Pteridium aaquilinum FACU
Herb American Vetch Vicia americana FAC
2. Soils
Hydric soils are soils that formed under conditions of saturation, flooding, or ponding long
enough during the growing season to develop anaerobic conditions in the upper soil horizon
(NRCS). Most hydric soils exhibit characteristic morphologies that result from repeated periods
of inundation or saturation that last more than a few days. Saturation or inundation, when
combined with microbial activity in the soil, causes a depletion of oxygen. This anaerobic state
promotes certain biogeochemical processes, such as the accumulation of organic matter, the
accumulation or reduction of iron, and other reducible elements.
These processes in turn create regionally specific, visible indicators, which help identify and
delineate hydric soils in a field setting. These indicators are not intended to replace or modify
the requirements contained in the definition of a hydric soil; they are dynamic, and open to a
degree of human interpretation. Some hydric soils lack any currently listed and accepted
indicators; therefore, the lack of any listed indicator does not prevent classification of a particular
soil as hydric. However, such soils and their specific morphologies, are included and specified in
the necessary field guides.
In this wetland, hydric soils were identified using the 2013 Pocket Guide to Hydric Soil Field
Indicators, prepared by the Wetland Training Institute, Inc, in conjunction with the Munsell Soil
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 11 | M S A
Color Book, a standard reference manual prepared by the Munsell Color Company and used by
the United States Department of Agriculture. Wetland test plot soil findings are as follows:
Wetland 1 – Sample Plot A – Wet
Depth
(inches)
Matrix Redox Features Texture
Color % Color % Type1 Loc2
0-6” 10YR2/1 100 N/A - - - Sandy Clay
6-9” 10YR3/1 99 10YR4/6 1 C PL Silty Clay
9-14” 10YR2/1 99 10YR6/8 1 C PL Silty Clay
14-15” 10YR3/2 93 10YR4/6 7 RM M Sandy Clay
1Type: C=Concentration, RM=Reduced Matrix, D=Depletion, CS=Covered or Coated
Sand Grains
2Location: PL=Pore Lining, M=Matrix
Wetland 1 – Sample Plot B – Wet
Depth
(inches)
Matrix Redox Features Texture
Color % Color % Type1 Loc2
0-13” 10YR2/1 100 N/A - - - Loam
13-14” 10YR2/1 95 10YR3/6 5 RM M Silty Clay
1Type: C=Concentration, RM=Reduced Matrix, D=Depletion, CS=Covered or Coated
Sand Grains
2Location: PL=Pore Lining, M=Matrix
In wetland test plots A and B, hydric soils were indicated. In both upland test plots, soils were
determined to be a sandy loam (See Appendix A; Data Forms).
3. Hydrology
Hydrologic conditions result from the interactions between meteorological, surface and ground
water, as well as physical and biological factors that influence the flow, quality, or timing of
water. Therefore, the determination of the presence of hydrologic conditions focuses on the
corresponding presence of factors that most directly influence the persistence of water in a
specific area. Similar to the indicators used in hydric soils, and because watersheds vary
tremendously across the country, regional hydrologic indicators are used to more easily identify
wetlands in the field.
Both wet test plots in Wetland 1 displayed the same four Primary Hydrology Indicators (water
marks, algal mat or crust, inundation visible on aerial imagery, and a sparsely vegetated concave
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 12 | M S A
surface), as well as the same three Secondary Hydrology Indicators (dry-season water table,
saturation visible on aerial imagery, and geomorphic position) (Appendix A; Data Forms)
All dry test plots in Wetland 1 displayed none of the Primary or Secondary Indicators for
wetland hydrology (Appendix A; Data Forms).
Wetland 2 (Figure 8)
Paired Data Point GPS Co-ordinates:
Plot A – Wet: 48.10608N 122.81250W
Plot A – Dry: 48.10598N 122.81250W
Plot B – Wet: 48.10610N 122.81244W
Plot B – Dry: 48.10604N 122.81224W
Plot C – Wet: 48.10614N 122.81287W
Plot C – Dry: 48.10629N 122.81293W
Plot D – Wet: 48.10638N 122.81245W
Plot D – Dry: 48.10616N 122.81244W
1. Vegetation
Due to limited biodiversity in a long-term agriculturally disturbed landscape and the
consequent redundancy of plant species, test plots are combined below.
Wetland 2 – Sample Plots A,B,C and D – Wet
Stratum Common Name Latin Name Status
Herb Soft Rush Juncus Effusus FACW
Herb Reed Canarygrass Phalaris arundinacea FACW
Wetland 2 – Sample Plots A, B, C and D – Dry
Stratum Common Name Latin Name Status
Tree Scouler’s Willow Salix scouleriana FAC
Shrub Nootka Rose Rosa Nutkana FACU
Shrub Scotch Broom Cytisus scoparius FACU
Herb Narrowleaf plantain Plantago lanceolate FACU
Herb American Vetch Vicia americana FAC
Herb Orchard Grass Dactylis glomerata FACU
Herb Colonial Bentgrass Agrostis capillaris FAC
Herb Reed Canarygrass Phalaris arundinacea FACW
Herb Canadian Thistle Cirsium arvense FAC
Herb Common Sheep Sorel Rumex acetosella FACU
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 13 | M S A
Herb Creeping Buttercup Ranunculus repens FACU
Herb Common Dandelion Taraxacum officinale FACU
2. Soils
Wetland 2 – Sample Plot A – Wet
Depth
(inches)
Matrix Redox Features Texture
Color % Color % Type1 Loc2
0-10” 10YR2/2 99 2.5YR4/6 1 C PL Loam
10-13” 10YR4/1 75 10YR3/6 25 C M Sandy Loam
13-16” 10YR2/2 85 10YR3/6 15 - PL+M Loam3
1Type: C=Concentration, RM=Reduced Matrix D=Depletion, CS=Covered or Coated Sand
Grains
2Location: PL=Pore Lining, M=Matrix
3Depleted matrix present with redox in some pore linings
Wetland 2 – Sample Plot B – Wet
Depth
(inches)
Matrix Redox Features Texture
Color % Color % Type1 Loc2
0-8” 10YR2/1 97 10YR5/6 3 C PL Loam
8-16” 10YR3/2 95 10YR4/6 5 C PL Clay Loam
1Type: C=Concentration, RM=Reduced Matrix D=Depletion, CS=Covered or Coated
Sand Grains
2Location: PL=Pore Lining, M=Matrix
Wetland 2 – Sample Plot C – Wet
Depth
(inches)
Matrix Redox Features Texture
Color % Color % Type1 Loc2
0-6” 10YR2/1 100 N/A - - - Clay Loam
M 10YR2/1 98 10YR5/6 2 RM PL Silty Clay
9-14” 10YR2/1 99 10YR6/8 1 C PL Silty Clay
14-15” 10YR3/2 93 10YR4/6 7 RM M Sandy Clay
1Type: C=Concentration, RM=Reduced Matrix D=Depletion, CS=Covered or Coated
Sand Grains
2Location: PL=Pore Lining, M=Matrix
Wetland 2 – Sample Plot D – Wet
Depth
(inches)
Matrix Redox Features Texture
Color % Color % Type1 Loc2
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 14 | M S A
0-5” 10YR2/1 100 N/A - - - Silty Loam
5-15” 2.5YR5/1 70 10YR3/6 30 RM M Silty Clay
1Type: C=Concentration, RM=Reduced Matrix D=Depletion, CS=Covered or Coated Sand
Grains
2Location: PL=Pore Lining, M=Matrix
In wetland test plots A, B, C and D hydric soils were indicated. In all upland test plots, soils were
determined to be a sandy loam (See Appendix A).
3. Hydrology
Wet test plots in Wetland 2 displayed most of the same three Primary Hydrology Indicators
(algal mat or crust, iron deposits, inundation visible on aerial imagery); select individual wet test
sites also showed oxidized rhizospheres along living roots. Wet test plots in Wetland 2 displayed
most of the same two Secondary Hydrology Indicators (saturation visible on aerial imagery,
geomorphic position); one individual wet test site also showed water stained leaves (Appendix
A; Data Forms).
All dry test plots in Wetland 2 displayed none of the Primary or Secondary Indicators for
wetland hydrology (Appendix A; Data Forms).
VI. Wetland Rating
The intent of a rating is to provide a basis for protecting and managing wetlands; this is
accomplished assessing a wetland’s valued functions and resources -- ecological, economic, or
aesthetic. In the process of a rating, a wetland is given a score according its comparison to
standardized categories and specific attributes such as rarity, sensitivity to disturbance, and the
functions they provide. Based upon this score, the wetland is then placed in Category 1 through
Category 4; the former is a wetland of greatest value, based upon the rating rubric’s
characterization of its inherent value, while the latter is a wetland of least value. A specific
buffer, identified in accordance with each individual wetland’s rating score, is then
recommended, using standardized and established guidelines. While all wetlands provide some
functions and resources that are valued, be they ecological, or aethestic, they also vary widely;
consequently, the recommended buffer, identified in accordance with each individual wetland’s
rating score, reflects that particular wetland and its specific qualities.
Of the four wetland areas investigated on the property, each one was determined to fall into the
class of Depressional. According to the Washington State Wetland Rating System for Western
Washington 2014 Update (Hruby 2014), Depressional wetlands occur in topographic depressions
where the elevation of the surface within the wetland is lower than in the surrounding landscape.
The shapes of Depressional wetlands vary, but in all cases, the movement of surface water and
shallow subsurface water is toward the lowest point in the depression. The depression may have
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 15 | M S A
an outlet, but the lowest point in the depression is somewhere within the boundary, not at the
outlet.
The wetlands were rated using the Washington State Wetland Rating System for Western
Washington (2014 Update). When the final wetland category is determined, it is based on either
functions or special characteristics (whichever is higher). The rating system for special
characteristics was designed to differentiate among wetlands based on their sensitivity to
disturbance, their significance, their rarity, the ability to replace them and the functions they
provide. Wetlands identified with special characteristics are rated by function in addition to
special characteristics because in some cases there are additional buffer widths due to a very high
score in one of the three functions listed below.
In accordance with City of Port Townsend Municipal Code Chapter 19.05.110(E), Buffers and
Setbacks, and Jefferson County Code, Table 18.22.330(3), Wetland Categories, Rating Scores
and Buffer Widths, rating categories are divided into four grades, in order of descending buffer
size: Category I with total scores of 23-27; Category II with total scores of 20-22; Category III
with total scores of 16-19; Category IV with total scores of 9-15.
The category of wetland based on functions is rated by the following parameters:
1) Water Quality Functions: a wetland’s potential to improve water quality
a) Potential of the wetland to improve water quality of and surrounding the wetland.
b) Potential of the wetland to support the water quality function of and surrounding the
wetland. (This parameter regards the ability of the wetland to mitigate for and lessen
the toxicity of potential pollutants on and surrounding the wetland).
c) Potential of local water quality improvement provided by the wetland to
benefit adjacent waters.
2) Hydrologic Functions: a wetland’s potential to improve hydrology
a) Potential to reduce flooding and erosion
b) Potential of wetland to support the hydrologic functions of the site (this parameter
regards the ability of the wetland in reducing the toxicity of potential pollutants on-
site and up-gradient of the wetland).
c) Potential of wetland to help capture surface water that might otherwise flow down-
gradient into areas where flooding might occur.
3) Habitat Functions: a wetland's potential to provide important habitat/ecological value
a) Potential of the wetland to provide habitat for natural living systems.
b) Potential of the accessible and undisturbed habitat and land use intensity surrounding
the wetland to support the habitat functions of the site.
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 16 | M S A
c) Value of wetland to society; degree to which it provides habitat for species valued in
laws, regulation, or policy.
Wetland 1 – Rated Category IV – Buffer of 40 Feet (Figure 7)
This wetland, which is found in the National Wetlands Inventory (Figure 2), is approximately
0.30 acres. It is relatively homogenous in shape and boundary, amidst a field of agricultural land;
MSA wetland specialists surmised it must have served as a livestock watering hole at some
point. As there are no Special Rating characteristics within the wetland and its associated 330
foot surroundings, the wetland was rated, based on its functions, to be a Category IV
Depressional wetland (Appendix A; Data Forms).
As the property owners have expressed interest in the northern central section as a possible
building site, the buffer was established according to the City of Port Townsend Municipal Code
19.05.110(E) for moderate impact land uses (single-family residential use on parcels larger than
one acre) at 40 feet (Figure 1).
As defined earlier in this report, Wetland 1 was also delineated; this delineation boundary was
used to establish the baseline for the 40-foot buffer.
Wetland 2 – Rated Category IV – Buffer of 40 Feet (Figure 8)
This wetland, which is found in the National Wetlands Inventory (Figure 2), is approximately
0.47 acres. It is approximately horseshoe in shape and generally homogenous of boundary,
amidst a field of agricultural land; as it directly abuts the existing farmhouse, MSA wetland
specialists surmised it may have been further developed as a recreational pond. As there are no
Special Rating characteristics within the wetland and its associated 330-foot surroundings, the
wetland was rated, based on its functions, to be a Category IV Depressional wetland (Appendix
A; Data Forms)
As the property owners have expressed interest in the northern central section as a possible
building site, and as Wetland 2 currently abuts the existing single farmhouse, the buffer was
established using City of Port Townsend Municipal Code 19.05.110(E) for moderate impact land
uses (single-family residential use on parcels larger than one acre) at 40 feet (Figure 1). As
defined earlier in this report, Wetland 2 was also delineated; this delineation boundary was used
to establish the baseline for the 40-foot buffer.
Wetland 3 – Rated Category 1V – Buffer of 60 Feet (Figure 9)
This wetland, which is found in the National Wetlands Inventory (Figure 2), is approximately
1.48 acres. It is relatively elongate in shape, running from northwest-to-southeast and its
boundary is relatively homogenous. The southern portion of this wetland is approximately 30
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 17 | M S A
feet from 5th Street, a neighboring residential road, as well as being approximately 100 feet from
a neighboring single-dwelling home. According to aerial photographs and satellite images from
the past, this area is generally wetter than Wetlands 1 and 2; the southern property line is
generally lower in elevation than the northern property line, and topography slopes in a generally
southeast direction. As there are no Special Rating characteristics within the wetland and its
associated 330-foot surroundings, the wetland was rated, based on its functions, to be a Category
IV Depressional wetland.
Given the location of Wetland 3, this buffer was established according to the City of Port
Townsend Municipal Code 19.05.110(E) (updated for use with the 2014 rating system) for high
impact land use wetlands without a delineated boundary (single-family residential use on parcels
larger than one acre; public roads) at 50 feet (Figure 1); an additional 10 feet was added to this
buffer based to reach the slightly more conservative buffer of 60 feet recommended by Jefferson
County Code table 18.22.330(2). The boundary for this wetland buffer was found using field
vegetative indicators, aerial photography, satellite imagery, and GPS.
Wetland 4 – Unrated at Property Owners Request – Buffer of 350 Feet (Figure 10)
This wetland is approximately 4.55 acres. It is relatively elongate in shape; located in the western
1/8th of the property, it runs approximately northwest-to-southeast. A smaller wetland, along
with a freshwater pond, is found in the National Inventory of Wetlands. Upon field research and
examination of aerial photographs and satellite images, MSA wetland specialists determined that
the smaller wetland and the freshwater pond are hydrologically contiguous and form the ends of
a larger wetland corridor (4.55 acres). The southeastern end of this wetland abuts the southern
property line; the northwestern end abuts the northwestern property line. According to aerial
photographs, satellite images, and topographical maps, flow moves in a generally southeast
direction. The area is generally agricultural grassland, with scattered scrub-shrub forest.
This wetland was not rated; however, based on MSA specialists experience with the rating
system in general, as well as the ability to compare it to the three other Category IV wetlands on
the property, it is very like that Wetland 4 would be categorized as a Category IV as well. On
request of the property owner, with thought to preserve the area in its current state for potential
future easement, a buffer was established based on Jefferson County Code table 18.22.330(2)
specifications for a Category 1 wetland of high impact land use without a delineated boundary:
350 feet. The boundary for this wetland buffer was found using field vegetative indicators, aerial
photography, satellite imagery, and GPS.
VII. Proposed Site Restoration/Developmental Changes
As stated earlier in this report, the current property owners desire to direct future land use within
these ten parcels toward a more sustainable, lower impact category than recent agricultural
history. Part of that shift will include physical changes on the landscape (removal/decommission
of certain structures, and construction/installation of certain other structure). As part of this
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 18 | M S A
wetland report below is an assessment of how those changes will affect the wetlands and wetland
buffers on the property.
Existing Farm House Removal
Currently, the onsite dwelling infringes on the buffer of Wetland 2 (Figure 5). Therefore, it is
proposed that instead of being rehabilitated from its current dilapidated state, the current
farmhouse be removed. The potential impacts of the removal of this existing structure to
Wetland 2 and associated buffer are listed below.
A. Temporary Impacts
Since the current house is within the established buffer of Wetland 2, its removal will involve
potential temporary negative impacts to the wetland buffer and potentially the wetland itself.
Potential negative impacts include but are not limited to:
i. Compaction of soils within wetland buffer and potentially wetland;
ii. denudation of vegetation within wetland buffer and potentially wetland;
iii. increased runoff and siltation into wetland due to denudation;
iv. decreased water quality and aquatic habitat due to increased siltation;
v. presence of pollutants/fuels in wetland buffer or wetland, resulting from either removal of
existing home;
vi. presence of staged materials and debris within wetland buffer;
vii. Presence of opportunistic invasive vegetation (ex: Scotch broom, reed canary grass, etc.)
in disturbed area after removal of existing structure.
B. Mitigation of Temporary Impacts
The following measures are recommended to reduce the potential negative temporary impacts
listed above:
i. Demolition and removal of the existing home will take place during the dry season, when
substrate will be more resistant to compaction. Use of heavy machinery will be kept to a
necessary minimum within wetland buffer and wetland. If soil compaction occurs, soil
turning/aeration will occur before any necessary planting (see ii).
ii. Use of heavy machinery will be kept to a necessary minimum within wetland buffer and
wetland. Where necessary, should the use of heavy machinery for demolition result in
destruction of existing vegetation, area will be planted with appropriate native wetland
plantings after removal process is complete. This will include the section of the wetland
buffer that is now occupied partially by the current structure.
iii. Demolition and removal of the existing home, will take place during the dry season;
therefore, increased runoff due to increased bare soil/decreased vegetation will be
minimal/non-existent. Should there be unexpected precipitation during the
demolition/removal process, silt fencing will be placed between the action area and the
wetland to reduce any additional inflow of sediment into the wetland.
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 19 | M S A
iv. For the reasons listed above in (iii), it is unlikely that any decrease in water quality or
aquatic habitat will occur due to increased siltation. Additionally, because the work will
take place during the dry season, it is likely that the wetland (designated a seasonal
wetland) will be dry, and therefore not suffer a negative impact to water quality.
v. Any fuels necessary, for heavy machinery that has been deemed necessary for
demolition/removal of the current house, will be stored outside of the wetland and the
wetland buffer. Said fuels will be stored in sealable, industry-standard containers and
stored in a dedicated covered area out of the sun, to avoid any possible
expansion/bursting due to excess heat. Special care will be taken to avoid any discharge
of pollutants into the wetlands and/or wetland buffers. All equipment will be checked for
leaks before entering the property. If any spill should occur, it will be cleaned up
immediately.
vi. All materials/equipment, during both the demolition/removal process, will be stored in
dedicated areas outside the wetland and wetland buffer, to be ultimately either used or
removed from site. Any waste products/remnant building materials from the demolition
will be stored out of the wetland buffer, to be ultimately removed from site and disposed
of at an approved offsite location.
vii. After removal of existing structure, newly available wetland buffer will be aerated (see i)
and planted with native wetland vegetation (see ii), to naturally suppress and out-compete
opportunistic non-native competing vegetation.
C. Long-Term Impacts
Long-term impacts of removing an outdated farmhouse from within a wetland buffer are as
follows:
i. A reduction in the total impervious surface within the buffer of Wetland 2 from
approximately 765 square feet to 0 square feet;
ii. An increase in native vegetated area within the wetland buffer by approximately 765
square feet;
iii. Increased water quality within wetland due to increased filtration capacity of buffer;
iv. An increase in distance between human impact (house) and Wetland 2 from
approximately 3 feet to approximately 40 feet;
v. More available habitat (invertebrate, amphibian, avian);
D. Summary of Old Farmhouse Demolition and Removal Impacts
The removal of an existing farmhouse from within the buffer of Wetland 2 carries certain risks
and potential impacts, most of them being short-term. As listed above, the materials, equipment,
and fuels used to remove the existing structure could potentially have negative impact on
Wetland 2 and its associated buffer.
With best management and building practices, as well as the mitigation measures listed above,
there will be a net shift of approximately 765 square feet within the established wetland buffer
from impervious, high-impact land use to pervious, natively vegetated, low-impact land use.
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 20 | M S A
There will be no net loss of habitat function and value within the wetland buffer due to the
removal of the existing structure.
Construction of replacement farmhouse
To replace the old farmhouse after its removal from the buffer of Wetland 2, a new construction
is proposed. A building designer identified an alternative site that will result in a new build
footprint completely outside the established buffer of Wetland 2 (Figure 6), as well as all other
wetlands on the property. The new structure measures 40 feet x 48 feet, equaling 1920 square
feet. It is set back 40 feet to the north of the existing driveway, and 50 feet (40-foot buffer + 10-
foot setback) directly south of mapped Wetland 2. There will be an approximately 50 feet x 50
feet gravel parking area contiguous to the proposed new structure.
A. Temporary Impacts
i. Compaction of soils within wetland buffer and potentially wetland;
ii. denudation of vegetation within wetland buffer and potentially wetland;
iii. increased runoff and siltation into wetland due to denudation;
iv. decreased water quality and aquatic habitat due to increased siltation;
v. presence of pollutants/fuels in wetland buffer or wetland resulting from construction of
new home outside buffer;
vi. presence of staged construction materials and debris within wetland buffer;
vii. presence of opportunistic invasive vegetation (ex: Scotch broom, reed canary grass, etc.)
in disturbed area after construction disturbance.
B. Mitigation of Temporary Impacts
The following measures are recommended to reduce the potential negative temporary impacts
listed above:
i. Construction of the new structure will take place during the dry season, when substrate
will be more resistant to compaction. Use of heavy machinery will be restricted from
operating within wetland buffer wherever possible; if absolutely necessary, use of heavy
machinery will be kept to a minimum within wetland buffer. Use of heavy machinery
will be completely restricted from operating within wetland. If soil compaction occurs
where heavy machinery is used, soil turning/aeration will occur before any necessary
planting (see ii).
ii. Use of heavy machinery will be restricted from operating within the wetland buffer
wherever possible; if absolutely necessary, use of heavy machinery will be kept to a
minimum within wetland buffer. Use of heavy machinery will be completely restricted
from operating within wetland. Where necessary, should the use of heavy machinery for
construction result in destruction of existing vegetation, area will be aerated (see i) and
planted with appropriate native wetland plantings after removal process is complete.
iii. Construction of new structure will take place during the dry season; therefore, increased
runoff due to increased bare soil/decreased vegetation will be minimal/non-existent.
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 21 | M S A
However, as precaution, silt fencing will be placed between the action area and the
wetland to reduce any additional inflow of sediment into the wetland.
iv. For the reasons listed above in (iii), it is unlikely that any decrease in water quality or
aquatic habitat will occur due to increased siltation. Additionally, because the work will
take place during the dry season, it is likely that the wetland (designated a seasonal
wetland) will be dry, and therefore not suffer a negative impact to water quality.
v. Any fuels necessary, for heavy machinery that has been deemed necessary for
construction of the new structure, will be stored outside of the wetland and the wetland
buffer. Said fuels will be stored in sealable, industry-standard containers and stored in a
dedicated covered area out of the sun, to avoid any possible expansion/bursting due to
excess heat. Special care will be taken to avoid any discharge of pollutants into the
wetlands and/or wetland buffers. All equipment will be checked for leaks before entering
the property. If any spill should occur, it will be cleaned up immediately using industry
standards and approved disposal.
vi. All materials/equipment used during the construction of the proposed structure will be
stored in dedicated areas outside the wetland and wetland buffer, to be ultimately either
used or removed from site. Any waste products/remnant building materials from the
demolition will be stored out of the wetland buffer, to be ultimately removed from site
and disposed of at an approved offsite location.
vii. After completion of proposed structure, all disturbed areas will be aerated (see i) and
planted with native wetland vegetation (see ii), to naturally suppress and out-compete
opportunistic non-native competing vegetation.
C. Long-Term Impacts
i. Vegetation – Wetland and Upland Areas
The property is dominated with Agrostis capillaris, Dactylis glomerata, and Phalaris
arundinacea. As the proposed construction site is on a historic building footprint (dating
from before the currently standing farmhouse), the land has already been excavated and is
dominated by these same plant species. Vegetation within the building footprint will be
removed but all other native vegetation onsite will remain. Because the proposed
construction footprint is outside the wetland and its associated buffer, no wetland
vegetation will be disturbed.
ii. Wildlife
Wildlife barriers or loss of connectivity are not expected to occur from the proposed
building which will be in an area of the property closest to an existing driveway, and near
to the current house site. The majority of the 77 acres will be unaffected by the proposed
structure. Additionally, the area to the west of the cumulative parcels will eventually be
utilized as a green belt, preserved for community access. Open space will also be
maintained between the proposed residence and developments on neighboring properties
that can easily be traversed by wildlife.
iii. Wetland Function
Development along wetland buffers can alter physical processes and ecological functions,
including potential adverse effects on sedimentation, erosion/accretion, and water quality.
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 22 | M S A
Increased run-off from the building area or any increase in impervious surfaces can
increase the potential for erosion.
iv. Noise
Some temporary increases in ambient noise will be generated during development of the
property. Noise generated during construction is not expected to impact wildlife or
ecosystem function in the long term.
v. Water Quality
Increased run-off from the building area or other impervious surfaces could occur with
development on the property. Avoidance and minimization measures described in the
following section include reducing the square footage of new impervious surfaces and
locating the development away from the stream.
D. Avoidance and Mitigation
Although the proposed construction footprint is outside any wetland buffers, it is close in
proximity. Therefore, General Protection Standards for property containing a designated
conservation area or its buffer (as described in JCC 18.22.270 and COPT municipal code) will be
employed:
• Drainage and Erosion Control: a silt fence will be installed around the perimeter of the
development during construction to prevent loose soil from entering the stream and
stream buffer.
• Grading: The parcel is relatively flat and no significant regrading should occur.
• Vegetation Retention:
o Clearing of any trees, understory and stumps will only occur where necessary to
complete the proposal involved in the project application.
o Trees and understory lying outside of road rights-of- way and utility easements
shall be retained (except for hazard trees) during clearing for roadways and
utilities; provided, that understory damaged during approved clearing operations
may be pruned.
o Damage to vegetation during initial clearing activities shall be minimized by
directional felling of trees to avoid critical areas and vegetation to be retained.
Additional avoidance and minimization measures recommended for the applicant as part of this
HMP include:
• A temporary barrier fence will be placed during construction along development area
boundaries to prevent machinery and other equipment from disturbing the stream buffer.
• Trees felled for construction will be placed on site, parallel to stream to mark the buffer
boundary on the north side of stream.
E. Summary of Replacement Farmhouse Construction Impacts
The construction of a replacement to the existing farmhouse carries certain risks and potential
impacts, most of them being short-term. As listed above, the materials, equipment, and fuels
used to construct the proposed structure could potentially have negative impacts on Wetland 2
and its associated buffer.
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 23 | M S A
With best management and building practices, as well as the fact the proposed construction will
be entirely outside the delineated wetland and established buffer, the new farmhouse falls within
the aim of shifting from high-impact land use to overall low-impact land use. It is anticipated
that there will be no net loss of habitat function and value within the wetland buffer due to the
proposed construction.
Decommission of Existing Septic System
The septic system of the existing home will be decommissioned (Figure 5), as the existing
structure associated with the system is being demolished and removed. The current system
consists of a septic tank, which is approximately 10 feet outside the buffer of Wetland 2, a
former drainfield for the system, and an existing drainfield, both of which are within the buffer
for Wetland 2.
The decommission process, which is standard within the industry, consists of abandonment by
pumping the tank dry, removing the lid, and filling with soil. A receipt from the pumper and a
certification of septic tank abandonment will be provided, using a standard form provided by the
septic designer Creative Solutions. The old drainfields will be abandoned, without need to
remove/cover any aspects.
A. Short-Term Impacts
Potential short-term effects of decommissioning the existing septic system are as follows:
i. Compaction of soils within wetland buffer and potentially wetland;
ii. denudation of vegetation within wetland buffer and potentially wetland;
iii. increased runoff and siltation into wetland due to denudation;
iv. decreased water quality and aquatic habitat due to increased siltation;
v. presence of pollutants/fuels in wetland buffer or wetland resulting from construction of
new home outside buffer;
vi. presence of staged construction materials and debris within wetland buffer;
vii. presence of opportunistic invasive vegetation (ex: Scotch broom, reed canary grass, etc.)
in disturbed area after construction disturbance.
B. Mitigation of Short-Term Impacts
Because the existing septic tank (the only part of the system that will require heavy machinery)
lies within the action area associated with demolishing and removing the existing structure, the
mitigation measures recommended to reduce impact are identical to those recommended in
VII.1.B.
C. Long-Term Impacts
i. A cessation of the use of partial wetland buffer for septic drainfield;
ii. a decrease in nutrient input to wetland, due to (i);
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 24 | M S A
iii. a decrease in eutrophication within wetland, due to (i);
iv. improved water quality within wetland due to increased filtration capacity of buffer;
v. improved water quality downstream within watershed
vi. More available habitat (invertebrate, amphibian, avian);
D. Summary of septic system decommission and abandonment
The decommission and abandonment of the existing septic system, located approximately 10 feet
from the buffer for Wetland 2 carries certain risks and potential impacts, most of them being
short-term. As listed above, the materials, equipment, and fuels used to decommission the septic
system could potentially have negative impact on Wetland 2 and its associated buffer.
With best management and building practices, as well as the mitigation measures listed above,
there will be a net reduction of high-impact, in-ground land use to natively vegetated, low-impact
land use. By abandoning the existing system, there will be a cessation of nutrient-rich influx into
the established wetland buffer and wetland, which will in turn improve water quality both locally
and downstream within the watershed.
There will be no net loss of habitat function and value within the wetland buffer due to the
decommission and abandonment of the existing structure.
Installation of New Septic System
To support the new farmhouse, a new septic system is proposed. A septic designer identified an
alternative site that will result in a two-part septic system: a pumphouse and temporary storage
tank to the west of the proposed new farmhouse, and a combination of biofilter units to the
northwest of the existing farmhouse footprint, along with a surrounding drainfield. All proposed
septic components are located outside the established buffer of Wetland 2 (Figure 5).
The new pumphouse and temporary storage unit has a capacity of 1000 gallons. The larger
storage/filter area to the northwest consists of 4 initial Glendon biofilter M31 units with a
absorption capacity of 206 square feet each. The surrounding drainfield is a 200% initial and
reserve drainfield measuring 4,378 square feet. For details, see separate septic permitting
document associated with this location. For specific details regarding the system, please see
separate septic proposal prepared for this property.
A. Short-Term Impacts
Potential short-term effects of decommissioning the existing septic system are as follows:
i. Compaction of soils within wetland buffer and potentially wetland;
ii. denudation of vegetation within wetland buffer and potentially wetland;
iii. increased runoff and siltation into wetland due to denudation and presence of drainfield;
iv. decreased water quality and aquatic habitat due to increased nutrient influx from
drainfield;
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 25 | M S A
v. presence of pollutants/fuels in wetland buffer or wetland resulting from installation of
new septic system;
vi. presence of staged construction materials and debris within wetland buffer;
vii. presence of opportunistic invasive vegetation (ex: Scotch broom, reed canary grass, etc.)
in disturbed area after construction disturbance.
B. Mitigation Recommendations for Reduction of Short-Term Impacts
The following measures are recommended to reduce the potential negative temporary impacts
listed above:
i. Construction of the new structure will take place during the dry season, when substrate
will be more resistant to compaction. For the installation of the 1000-gallon storage tank
and pumping station, use of heavy machinery will be restricted from operating within
wetland buffer wherever possible, and completely restricted from operating within
wetland. If soil compaction occurs where heavy machinery is used, soil turning/aeration
will occur before any necessary planting (see ii). For the installation of the larger
component of the septic system (the four initial Glendon biofilter units and the 200%
drainfield), the distance from the wetland is approximately 120 feet and well outside the
buffer; therefore, no negative impacts are expected.
ii. Use of heavy machinery will be restricted from operating within the wetland buffer
wherever possible; if absolutely necessary, use of heavy machinery will be kept to a
minimum within wetland buffer. Use of heavy machinery will be completely restricted
from operating within wetland. Where necessary, should the use of heavy machinery for
construction result in destruction of existing vegetation, area will be aerated (see i) and
planted with appropriate native wetland plantings after removal process is complete.
iii. Construction of new structure will take place during the dry season; therefore, increased
runoff due to increased bare soil/decreased vegetation will be minimal/non-existent.
However, as precaution, silt fencing will be placed between the action area and the
wetland to reduce any additional inflow of sediment into the wetland. Regarding
increased nutrient influx/runoff into wetland resulting from installation of septic system,
because of the size (200%) and location of the drainfield, it is unlikely that any additional
nutrient loading will affect the wetland.
iv. For the reasons listed above in (iii), it is unlikely that any decrease in water quality or
aquatic habitat will occur due to increased siltation or increased nutrient loading.
Additionally, because the work will take place during the dry season, it is likely that the
wetland (designated a seasonal wetland) will be dry, and therefore not suffer a negative
impact to water quality due to the installation disturbance.
v. Any fuels necessary, for heavy machinery that has been deemed necessary for
construction of the new structure, will be stored outside of the wetland and the wetland
buffer. Said fuels will be stored in sealable, industry-standard containers and stored in a
dedicated covered area out of the sun, to avoid any possible expansion/bursting due to
excess heat. Special care will be taken to avoid any discharge of pollutants into the
wetlands and/or wetland buffers. All equipment will be checked for leaks before entering
the property. If any spill should occur, it will be cleaned up immediately using industry
standards and approved disposal.
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 26 | M S A
vi. All materials/equipment used during the construction of the proposed structure will be
stored in dedicated areas outside the wetland and wetland buffer, to be ultimately either
used or removed from site. Any waste products/remnant building materials from the
demolition will be stored out of the wetland buffer, to be ultimately removed from site
and disposed of at an approved offsite location.
vii. After completion of proposed structure, all disturbed areas will be aerated (see i) and
planted with native wetland vegetation (see ii), to naturally suppress and out-compete
opportunistic non-native competing vegetation.
C. Long-Term Impacts
i. Vegetation – Wetland and Upland Areas
The area where the new septic will be installed (both smaller storage tank/pumping
station, and larger multiple tank area/drainfield) is dominated with Agrostis capillaris,
Dactylis glomerata, and Phalaris arundinacea. Vegetation within the proposed
installation footprint will be removed but all other native vegetation onsite will remain.
Because the proposed installation footprint is outside the wetland and its associated
buffer, no wetland vegetation will be disturbed, therefore no long-term impacts to
wetland are predicted.
ii. Wildlife
Wildlife barriers or loss of connectivity are not expected to occur from the proposed
septic installation which will be 1) in areas of the property closest to an existing
driveway, and 2) on a hillside that is currently covered in grass species. After the
installation and revegetation, installation areas will support the same wildlife function as
beforehand. The majority of the 77 acres will be unaffected by the proposed structure.
Additionally, the area to the west of the cumulative parcels will eventually be utilized as
a green belt, preserved for community access, which will be enabled by focusing
construction/impact on the eastern section of the property, away from the proposed green
belt. Open space will also be that can easily be traversed by wildlife.
iii. Wetland Function
Because of the location of the installations, and the oversize capacity of the drainfield,
there is no negative impact predicted to any wetlands or wetland buffers on the property.
iv. Noise
Some temporary increases in ambient noise will be generated during installation of the
septic system. Noise generated during construction is not expected to impact wildlife or
ecosystem function in the long term.
v. Water Quality
Increased run-off from the building area or other impervious surfaces could occur with
heavy machinery being used for installation of the new septic system on the property.
Avoidance and minimization measures described in the following section include
reducing the square footage of new impervious surfaces and locating the development
away from the stream.
D. Avoidance and Mitigation
David Cohn (3057 7th St, Port Townsend WA) Wetland Report 27 | M S A
Although the proposed septic installation is outside any wetland buffers, it is relatively close in
proximity. Therefore, General Protection Standards for property containing a designated
conservation area or its buffer (as described in JCC 18.22.270 and COPT municipal code) will be
employed: See above (VII.2.D)
In addition, as sourced from the septic design firm (Creative Design Solutions), the following
measures will be observed:
i. All systems shall meet the setback requirements set forth in the current Washington Stste
WAC regulations for the on-site sewage systems, “Rules and Regulations of the state
board of health”, or current local health division/department regulations.
ii. The contractor shall coordinate between product suppliers to ensure that their respective
products are constructed to be compatible with each other.
iii. All concrete tanks shall be made watertight
iv. All pipes shall be thoroughly flushed prior to adjustment and testing and installation.
v. All construction materials shall be stored and installed in a clean manner and shall be
support above ground prior to installation.
vi. Unless being worked on at that moment, all pipe openings shall be covered sufficiently to
prevent the entrance of undesirable materials.
vii. No organic material will be allowed in any of the fill material specified in designer’s
plans.
viii. The contractor shall document any and all changed in or deviations from the provided
plans.
E. Summary of Proposed Septic System Installation
The construction of a replacement septic system carries certain risks and potential impacts, most
of them being short term. As listed above, the materials, equipment, and fuels used to construct
the proposed septic system could potentially have negative impacts on Wetland 2 and its
associated buffer.
With best management and building practices, as well as the fact the proposed septic system will
be entirely outside the delineated wetland and established buffer, the new system falls within the
aim of shifting from high-impact land use to overall low-impact land use. It is anticipated that
there will be no net loss of habitat function and value.
IIX Summary
This wetland report documents the presence of four wetlands on the property of 3057 7th St, Port
Townsend WA. Two were delineated and rated, one was rated, and one was mapped. All four
were given buffers; three as according to specifications in City of Port Townsend Municipal
Code 19.05.110(E) for Category IV wetlands, and one according to specifications in Jefferson
County Code table 18.22.330(2) for a Category 1 wetland. The location and size of the wetlands
and their associated buffers is defined both in Appendix A, as well as Figure 1.
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This report also considers several developmental changes to that same property, proposed to both
improve livability and remediate years of high-impact, agricultural use. By adhering to best
construction/management practices, and by following mitigation recommendations set forth in
this report, it is believed that no net loss of habitat value or function will result from these
changes.
Respectfully submitted,
Marine Surveys and Assessments
______________________________
James Ialeggio
Staff Wetland Biologist
______________________________
Amy Leitman
Senior Biologist, Owner
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IX. References
Cowardin, LM., V. Carter, F.C. Golet and E.T. LaRoe, 1979. Classification of Wetlands and
Deepwater Habitats of the United States. U.S. Fish and Wildlife Service document FWS/OBS-
79/31. 84pp. Washington D.C.
Hitchcock, L.C. and A. Cronquist, 1973. Flora of the Pacific Northwest.
University of Washington Press. 730 pp.
Hruby, T., 2014. Washington State Wetland Rating System for Western Washington -
Revised. Washington State Department of Ecology Publication
#04-06-025.
Jefferson County Unified Development Code, Title 18, Article VII. July 2006.
Munsell Soil Color Charts, 1998. GretagMacbeth. North Windsor, New York.
Pocket Guide to Hydric Soil Field Indicators Based on Field Indicators of Hydric
Soils in the United States v. 7.0 with Updates, Prepared by Wetland
Training Institute, Inc., 2013
Regional Supplement to the Corps of Engineers Wetland Delineation Manual (1987):
Western Mountains, Valleys, and Coast Region (Version 2.0), US Army
Corps of Engineers, May 2010.
Speare-Cooke, S., 1997. A Field Guide to the Common Wetland Plants of
Western Washington and Northwestern Oregon. Seattle Audubon Society.
417 pp.
US Department of Agriculture, Soil Conservation Service. Soil Survey of Jeffeson County Area,
Washington. December, 2013
US Fish and Wildlife Service. National Wetlands Inventory. 1978
Washington State Department of Ecology, 1997. Washington State Wetland Indentification and
Delineation MAnual. Ecology Publication #96-94, Olympia, Washington.
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X. Figures
Figure 1. Site and Vicinity Map
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Figure 2. National Wetland Inventory (NWI) Map
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Figure 3. NRCS Soil Survey
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Figure 4. Vegetation Line Between Upland and Wetland
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Figure 5. Layout of Proposed Plan for New Farmhouse
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Figure 6. Proposed Farmhouse Design for City of Port Townsend
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Figure 7. Wetland 1
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Figure 8. Wetland 2
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Figure 9. Wetland 3
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Figure 10. Wetland 4
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XI. Appendix: Rating Images, Data Forms
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