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Washington State
Department of Transportation
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Approved By:
Debra M. Lewis Date
Colonel, Corps of Engineers
District Engineer
Ronald A. Kreizenbeck Date
Acting, Regional Administrator
Environmental Protection Agency, Region 10
Gordon White Date
Program Manager for Shorelands and Environmental Assistance Program
Washington State Department of Ecology
Ken Berg Date
Manager, Western Washington Fish and Wildlife Office
U.S. Fish and Wildlife Service
Daniel Mathis, P.E. Date
Division Administrator
Federal Highway Administration (exofficio)
Kathy Keolker Date
Mayor
City of Renton
Megan White, P.E. Date
Director, Environmental Services
Washington State Department of Transportation
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Table of Contents
Listof Acronyms and Abreviations..................................................................................v
ExecutiveSummary........................................................................................................ vii
1.0 INTRODUCTION AND BACKGROUND INFORMATION...................................1-1
1.1 PROJECT OVERVIEW...................................................................................1-1
1.1.1 General Mitigation Bank Goal and Objectives .......................................... 1-2
1.1.2 Project Setting............................................................................................
1-2
1.1.3 Site Selection Rationale.............................................................................
1-4
1.1.4 Bank Site Description.................................................................................
1-5
1.1:5 Unique Urban Setting and Public Access ..................................................
1-8
1.2 LEGAL AUTHORITY AND RESPONSIBILITIES OF
BANK SPONSOR AND PARTNERS............................................................1-11
1.2.1 WSDOT Memorandum of Agreement and the Bank Oversight
Committee...............................................................................................1-12
1.2.2 Responsibility of WSDOT and City of Renton........................................1-13
1.3 SERVICE AREA.............................................................................................1-13
1.4 REQUIRED PERMITS AND APPROVALS................................................1-15
1.4.1 Section 404 Permit...................................................................................
1-15
1.4.2 Section 401 Water Quality Certification..................................................1-16
1.4.3 Section 402 NPDES.................................................................................1-16
1.4.4 CZMA Consistency Determination..........................................................
1-16
1.4.5 Hydraulic Project Approval.....................................................................1-16
1.4.6 Endangered Species Act Biological Assessment .....................................
1-16
1.4.7 Shoreline Substantial Development Permit..............................................1-16
1.4.8 National Historic Preservation Act, Section 106 Compliance.................1-17
1.4.9 Other Approvals.......................................................................................1-17
2.0 ESTABLISHMENT OF THE BANK..........................................................................
2-1
2.1
MITIGATION BANK PLAN OVERVIEW ....................................................
2-1
2.2
CONSTRUCTION SCHEDULE......................................................................2-2
2.3
GRADING PLAN..............................................................................................
2-3
2.4
PLANTING PLAN.............................................................................................
2-3
2.5
WEED MANAGEMENT..................................................................................
2-5
2.5.1 Existing Site Conditions Favor Reed Canarygrass....................................
2-5
2.5.2 Reed Canarygrass Offers Some Understory Functions ..............................
2-5
2.5.3 Strategy to Manage Reed Canarygrass.......................................................
2-6
2.5.4 Strategy to Manage Himalayan Blackberry ...............................................
2-8
2.5.5 Strategy to Manage Other Invasive Non -Native Species ...........................
2-8
2.6
MITIGATION BANK PLAN...........................................................................
2-9
2.6.1 Units A and B.............................................................................................
2-9
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2.6.2 Unit C....................................................................................................... 2-14
2.6.3 Unit D....................................................................................................... 2-17
2.6.4 Unit E....................................................................................................... 2-18
2.7 FUNCTIONAL IMPROVEMENT................................................................ 2-20
2.7.1 Watershed Scale....................................................................................... 2-20
2.7.2 Mitigation Bank Unit Scale...................................................................... 2-21
2.8 CONSTRUCTION MONITORING.............................................................. 2-21
3.0 PROJECT GOAL, OBJECTIVES, AND PERFORMANCE STANDARDS .......... 3-1
3.1 GOAL..................................................................................................................3-1
3.2 ECOLOGICAL OBJECTIVES........................................................................3-1
3.3 PERFORMANCE STANDARDS.....................................................................3-1
3.4 REMEDIAL ACTION...................................................................................... 3-3
3.5 MAINTENANCE DURING THE ESTABLISHMENT PHASE .................. 3-4
4.0 BANK OPERATION.....................................................................................................4-1
4.1 CREDIT DETERMINATION..........................................................................4-1
4.2 APPROVING PERFORMANCE STANDARDS FOR CREDIT
RELEASE........................................................................................................... 4-1
4.3 USE OF CREDITS............................................................................................ 4-2
4.3.1 Credit Release Flexibility........................................................................... 4-4
4.4 ACCOUNTING PROCEDURES AND LEDGER MANAGEMENT .......... 4-6
4.5 SITE COMPLIANCE MONITORING........................................................... 4-6
5.0 SITE PROTECTION AND MANAGEMENT............................................................ 5-1
5.1 PROTECTION MECHANISMS......................................................................5-1
5.1.1 Conservation Easement.............................................................................. 5-1
5.1.2 Financial Assurances.................................................................................. 5-1
5.1.3 Site Access................................................................................................. 5-1
5.2 LONG-TERM MANAGEMENT GUIDELINES ........................................... 5-2
5.3 FORCE MAJEURE...........................................................................................5-2
6.0 GLOSSARY....................................................................................................................6-1
7.0 REFERENCES...............................................................................................................7-1
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List of Figures
Figure 1-1: Project Vicinity...................................................................................................... 1-18
Figure 1-2: Springbrook Bank Site........................................................................................... 1-19
Figure 1-3: Service Area........................................................................................................... 1-20
Figure 1-4:
Historical Aerial Photo...........................................................................................
1-21
Figure 1-5:
Unit A Existing Conditions....................................................................................
1-22
Figure 1-6:
Unit B Existing Conditions....................................................................................
1-23
Figure 1-7:
Unit C Existing Conditions....................................................................................
1-24
Figure 1-8:
Unit D Existing Conditions............................................................... .....................
1-25
Figure 1-9:
Unit E Existing Conditions....................................................................................
1-26
Figure 1-10:
Existing Vegetation..............................................................................................
1-27
Figure 2-1:
Mitigation Types Overview...................................................................................
2-27
Figure 2-2:
Units A and B Mitigation Types............................................................................
2-28
Figure 2-3:
Unit C Mitigation Types........................................................................................
2-29
Figure 2-4:
Unit D Mitigation Types........................................................................................
2-30
Figure 2-5:
Unit E Mitigation Types........................................................................................
2-31
Figure 2-6:
Units A and B Mitigation Treatment Activities.....................................................
2-32
Figure 2-7:
Unit C Mitigation Treatment Activities.................................................................
2-33
Figure 2-8:
Unit D Mitigation Treatment Activities.................................................................
2-34
Figure 2-9:
Unit E Mitigation Treatment Activities.................................................................
2-35
Figure 2-10:
Units A and B Grading Plan................................................................................
2-36
Figure 2-11:
Unit C Grading Plan..............................................................................................
2-37
Figure 2-12:
Unit D Grading Plan............................................................................................
2-38
Figure 2-13:
Unit E Grading Plan .............................................................................................
2-39
Figure 2-14:
Units A and B Planting Plan................................................................................
2-41
Figure 2-15:
Unit C Planting Plan............................................................................................
2-42
Figure 2-16:
Unit D Planting Plan............................................................................................2-43
Figure 2-17:
Unit E Planting Plan .............................................................................................
2-44
List of Tables
Table 1-1: Permit Activities and Environmental Documentation .............................................. 1-15
Table 2-1: Master Plant Materials List...............................................................................2-4, 240
Table 2-2: Mitigation Treatment Type and Acreage Summary by Unit ...................................... 2-9
Table 2-3: Units A and B: Exiting and Proposed Function Attributes ..................................... 2-23
Table 2-4: Unit C: Exiting and Proposed Function Attributes .................................................. 2-24
Table 2-5: Unit D: Exiting and Proposed Function Attributes .................................................. 2-25
Table 2-6: Unit E: Exiting and Proposed Function Attributes ................................................... 2-26
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Table 3-1: Units A and B: Summary of Performance Standards, Monitoring, Related
Objectives Functions and Values, and Function Attributes .................................................
3-5
Table 3-2: Unit C: Summary of Performance Standards, Monitoring, Related Objectives
Functions and Values, and Function Attributes...................................................................
3-6
Table 3-3: Unit D: Summary of Performance Standards, Monitoring, Related Objectives
Functions and Values, and Function Attributes...................................................................
3-7
Table 3-4: Unit E: Summary of Performance Standards, Monitoring, Related Objectives
Functions and Values, and Function Attributes..............................................................
3-8
Table4-1: Credit Potential...........................................................................................................
4-1
Table 4-2: Credits Required for Wetland Impacts.......................................................................4-3
Table 4-3: Credit Release Schedule for Springbrook Bank.........................................................4-5
Table 4-4: Formal Monitoring Schedule......................................................................................
4-7
Table 4-5: Informal Monitoring Schedule...................................................................................
4-7
Table 4-6: Sample Accounting Ledger........................................................................................
4-9
List of Appendices
Appendix A: Springbrook Creek Wetland and Habitat Mitigation Bank Monitoring Plan
Appendix B: Memorandum of Agreement
Appendix C: Conservation Easement
Appendix D: Agreement between City of Renton and WSDOT
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List of Acronyms and Abbreviations
AEMRA Advanced Environmental Mitigation Revolving Account
BA
Biological Assessment
BMP
Best Management Practice
BNSF
Burlington Northern Santa Fe
BOC
Bank Oversight Committee
CBMOA
Wetland Compensation Bank Memorandum of Agreement
Corps
U.S. Army Corps of Engineers
CZMA
Coastal Zone Management Act
DAHP
Department of Archaeology and Historic Preservation
DPS
Distinct Population Segment
DNS
Determination of Non -Significance
Ecology
Washington State Department of Ecology
EEI
Early Environmental Investments
EFH
Essential Fish Habitat
EPA
Environmental Protection Agency
ESA
Endangered Species Act
FHWA
Federal Highway Administration
HGM
Hydrogeomorphic
HOV
High Occupant Vehicle
HPA
Hydraulic Project Approval
I
Interstate
IM
Medium Industrial
IP
Individual Permit
LWD
Large woody debris
MBI
Mitigation Bank Instrument
MBRT
Mitigation Bank Review Team
MOA
Memorandum of Agreement
NAVD88
North American Vertical Datum 1988
NE
no effect
NEPA
National Environmental Policy Act
NLAA
may affect, but is not likely to adversely affect
NMFS
National Marine Fisheries Service
NPDES
National Pollution Discharge Elimination System
NRCS
Natural Resource Conservation Service
RC
Resource Conservation
RCG
Reed canarygrass
SEPA
State Environmental Policy Act
SR
State Route
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SSDP
Shoreline Substantial Development Permit
USFWS
U.S. Fish and Wildlife Service
WDFW
Washington State Department of Fish and Wildlife
WFAM
Washington State Wetland Function Assessment Methods
WQC
Water Quality Certification
WRIA
Water Resource Inventory Area
WSDOT
Washington State Department of Transportation
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Executive Summary
Location: The Springbrook Creek Wetland and Habitat Mitigation Bank (Springbrook
Bank) is located in the City of Renton, King County, Washington; Sections 25, 30, and
36, Township 23N, Ranges 4E and 5E; Lat 47' 27' 20" Long 122' 14' 24". Portions of
the site are adjacent to Springbrook Creek. Springbrook Bank is located in the Green-
Duwamish Watershed (Water Resources Inventory Area [WRIA] 9).
Service Area: The service area of Springbrook Bank includes portions of the Cedar-
Sammamish Watershed (WRIA 8) and the Green-Duwamish Watershed (WRIA 9).
Size of Bank: Springbrook Bank will generate 45.13 mitigation credits on the 129.22-
acre site. One credit compensates for one acre of Category II wetland.
Land Owner: The City of Renton (City) owns the land within Springbrook Bank.
Bank Sponsorss: The City and Washington State Department of Transportation
(WSDOT) will operate and manage Springbrook Bank.
Type of Bank: Springbrook Bank will generate wetland mitigation credits through the
re-establishment, rehabilitation, and enhancement of wetlands combined with the
enhancement of upland and riparian areas.
Purpose: The purpose of Springbrook Bank is to provide compensation for unavoidable
impacts to wetlands and other aquatic resources caused by WSDOT highway
construction projects and City mitigation requirements within the service area.
Goal: The goal of Springbrook Bank is to increase wetland area, improve hydrologic,
water quality and habitat functions, improve fish refuge/rearing habitat, and promote
environmental education.
Objectives: The objectives of Springbrook Bank are to re-establish 17.79 acres of
wetland, rehabilitate 52.16 acres of wetland, enhance 32.55 acres of wetland, and
enhance 7.80 acres of upland and 6.55 acres of riparian upland adjacent to Springbrook
Creek for a total of 116.86 acres; the remaining acreage consists of non-credit generating
buffers. The proposed restoration and enhancement activities will re -connect floodplain
wetlands with Springbrook Creek, re-establish historical wetlands, and improve water
quality, hydrologic, floodplain, habitat, and riparian functions in a highly urbanized area.
Use of Credits: WSDOT anticipates using its credits from Springbrook Bank for
transportation projects within the service area. The City will use its credits for projects
within the service area.
WSDOT Wetland Compensation Bank MOA: The Washington State Department of
Transportation Wetland Compensation Bank Program Memorandum of Agreement
(WSDOT 1994) provides the principles and procedures for establishing, implementing
and maintaining Springbrook Bank.
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1.0 INTRODUCTION AND BACKGROUND INFORMATION
The Mitigation Bank Instrument (Instrument) for the Springbrook Creek Wetland and
Habitat Mitigation Bank (Springbrook Bank) contains information required for its
approval. This document was prepared in accordance with the Washington State
Department of Transportation (WSDOT) Wetland Compensation Bank Program
Memorandum of Agreement (CBMOA) (WSDOT 1994), the Federal Guidance for the
Establishment, Use, and Operation of Mitigation Banks (US Army Corps of Engineers et
al. 1995), and negotiations with state and federal wetland regulatory agencies.
This Mitigation Banking Instrument will serve as the detailed implementation plan for the
establishment and long-term management of the Springbrook Bank. The terms and
provisions of this Instrument will be incorporated into the Memorandum of Agreement,
which governs the general relationship between WSDOT and the City of Renton
(Sponsors) and the regulatory agencies having jurisdiction over, and/or substantial
interest in, the Springbrook Bank. These regulatory agencies are referred to as the Bank
Oversight Committee (BOC). Where the term "Agreement" is used in this document, it
will refer collectively to the Memorandum of Agreement and this Instrument together.
1.1 PROJECT OVERVIEW
WSDOT and the City of Renton (City) will establish Springbrook Bank to provide
compensatory mitigation in advance of unavoidable impacts to wetlands and other
aquatic resources from future projects within portions of two watersheds: Cedar-
Sammamish Watershed (Water Resource Inventory Area [WRIA] 8) and Green-
Duwamish Watershed (WRIA 9). Springbrook Bank is being created as an Early
Environmental Investments (EEI) project under the Interstate 405 (1-405) Congestion
Relief and Bus Rapid Transit projects. Springbrook Bank consists of five units, totaling
129.22 acres, which represent some of the last remaining large tracts of undeveloped land
in the Lower Green River Basin. All five units are located in the southwestern portion of
the City of Renton, King County, Washington (Figures 1-1 and 1-2).
Portions of Springbrook Bank are adjacent to the lower reaches of Springbrook Creek.
This proximity to the creek will allow the water quality and hydrologic functions
provided in Units A, B, and E to benefit downstream aquatic habitat in Springbrook
Creek, the Green River, and the Duwamish River and its estuary. Springbrook Creek is
one of the few remaining tributary streams to the Green River. In a landscape that is
nearly completely developed, protecting and enhancing the last remaining natural areas is
a high priority. This protection will sustain the viability of remaining fish and wildlife
populations. The location of Springbrook Bank adjacent to the habitat corridor of
Springbrook Creek, other habitat corridors, and other mitigation sites greatly increases its
value within the surrounding landscape and complements existing restoration projects
both upstream and downstream. These functions would be difficult to replicate at another
location due to: urbanization of the surrounding landscape, lack of remaining natural
areas in the vicinity, connectivity to surrounding habitat, and the potential to provide
ecological benefits beyond site boundaries via this connectivity.
Construction and successful development of Springbrook Bank as described in this
Instrument will establish 45.13 mitigation credits. These credits will become available
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
for use by WSDOT and the City, in increments, as the performance standards specified in
Section 3.3 of this document are met and approved by the Bank Oversight Committee
(BOC). The BOC is analogous to the Mitigation Bank Review Team (MBRT)
established by the State of Washington (2001) and Federal Banking Guidance (U.S.
Army Corps of Engineers 1995) who oversees all other state and private mitigation
banks.
Projects that may use the credits from Springbrook Bank include the 1-405 Congestion
Relief and Bus Rapid Transit projects, State Route (SR) 518 improvement projects, and
the SR 167 15th SW to 15th NW HOV Stage 3 project. A portion of the credits will be
administered by the City to meet mitigation requirements for other projects within the
service area (Figure 1-3). Future WSDOT and City -approved projects within the service
area are eligible to use mitigation credits.
1.1.1 General Mitigation Bank Goal and Objectives
The goal of Springbrook Bank is to increase wetland area, improve hydrologic, water
quality, and habitat functions, increase fish refuge/rearing habitat, and promote
environmental education.
Project objectives are to improve floodplain and riparian functions, water quality, flood
storage capacity and other hydrologic functions, wildlife habitat, and establish site
buffers to protect habitat. A proposed public access trail will also provide increased
environmental educational opportunities for local residents and connect to the existing
King County regional trail systems.
1.1.2 Project Setting
Springbrook Bank is located within the relatively flat Green River Valley (Valley).
Springbrook Creek drains a watershed located on the east side of the Green River known
as the Black River Basin and is defined as the "Springbrook, Mill, and Garrison Creek
Watershed" (SMG watershed) (Harza 1995). The Black River Basin covers about 15,763
acres (24.6 square miles) and can be delineated into two distinct topographical areas: the
valley floor and the foothill zone. Slope gradient in the watershed ranges from 0 to 70
percent. Elevation in the watershed ranges between 10 and 525 feet above mean sea level
(Kerwin and Nelson 2000). All elevations referenced in this document are in the North
American Vertical Datum 1988 (NAVD88).
Springbrook Creek is the main water conveyance channel in the SMG watershed, with its
tributaries, Mill and Garrison Creeks, entering from the west (in Kent), and Panther and
Rolling Hills Creeks originating on plateaus east of the Valley. Springbrook Creek is
approximately 12 miles long (Kerwin and Nelson 2000). Downstream of SW 16th Street
and I-405, Springbrook Creek enters the improved portion of the Creek, the P-1 Channel,
which flows to the Black River Pump Station (Figure 1-1). In the forebay of the pump
station, water is stored prior to its discharge into the Green River. The pump station and
associated infrastructure prevents high flows in the Green River from backing water up
into Springbrook Creek, reducing the risk of flooding in adjacent areas.
The lower reaches of Springbrook Creek have been historically straightened, deepened,
and widened by farmers, local jurisdictions, the Natural Resources Conservation Service
(NRCS), and King County Drainage District #1 (Kerwin and Nelson 2000). Springbrook
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Creek was originally channelized for agricultural drainage purposes. Later conveyance
improvements were made to reduce flood hazards as part of the City of Renton and
NRCS East Side Green River Watershed Project (R.W. Beck 1996). Figure 1-4 shows
that Springbrook Creek was channelized by 1940 and the surrounding areas had
previously been converted to agricultural use. Existing wetlands within the Valley
provide several hundred acre-feet of flood storage during the most extreme events (R.W.
Beck 1996).
1.1.2a Current Land Use and Zoning
Springbrook Bank is located in an area of the City referred to as the Employment Area
Valley. According to the City of Renton Comprehensive Plan (Renton 2004), the
Employment Area Valley is "...intended to provide a mix of employment -based uses,
including commercial, office, and industrial development to support the economic
development of the City of Renton." The comprehensive plan objectives and policies
specific to the Employment Area Valley are intended to promote economic development.
Units A, B, C, and E are currently zoned as Resource Conservation (RC). Unit D
(adjacent to the business park located north of SW 43rd Street) is zoned Industrial -
Medium (IM). Urban development is allowed in accordance with the environmentally
sensitive area regulations found in the City's Critical Areas Ordinance (Renton 2005).
The RC zoning provides for a very low -density residential land use in combination with
environmentally sensitive areas or agriculture uses. Examples of RC -zoned land uses
include manufactured homes, eating or drinking establishments, day care centers, medical
institutions, and veterinary offices.
The IM zoning provides for medium -intensity industrial activities involving
manufacturing, processing, assembly, and warehousing. Examples of IM-zoned land use
include City government offices, schools, movie theaters, laboratories, power plants,
airplane manufacturing, and vehicle service stations.
As with any zoned land, the City can change the zoning and re -designate the areas for
other land uses. However, the establishment of Springbrook bank on these properties
will protect the site in perpetuity through a conservation easement.
1.1.2b Easements and Existing Utilities
WSDOT and the City of Renton are working together to release all easements (without
existing utilities in them) from the Springbrook bank site. All of the easements that
contained existing utilities have already been removed from the credit generating area of
the bank. Existing utility easements run through portions of Units D and E (see Figures
2-3 and 2-4).
These easements contain City sewer lines. The width of these easements is 15 feet.
However, 20 feet was taken out of the credit generating area to ensure enough space is
available for any work related to these facilities. This work would be conducted using
trenchless technology, if possible, or standard width track hoes and trench boxes. City
utilities staff verified that 20 feet is adequate to perform any activity related to the
maintenance or replacement of these facilities. In areas where existing easements and/or
facilities run along the edge of a bank unit, the boundary of the bank was moved back to
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the edge of the easement to ensure that any work related to these facilities will not impact
the mitigation area or its buffers.
Through a lot line adjustment the City will be able to release the majority of the vacant
easements. WSDOT and Renton are also working with the local electric company to have
them release their unused easements in Unit A and Unit B. All private property owners
with an interest in a vacant easement have been contacted and asked to release their
easements on the Units. The City's legal staff is working directly with these private
property owners to expedite the process to the extent possible. WSDOT and the City
anticipate that all vacant easements will be released from the bank parcels by the signing
of this Instrument. However, if the vacant easements have not been released by the time
the Year 0 (submittal of as -built plans) credits are scheduled to be released by the BOC,
WSDOT and the City will remove any remaining vacant easement areas from the credit
generating area within the bank. Updated maps, a new credit total, and new release
schedule will be submitted to the BOC.
1.1.3 Site Selection Rationale
The 129.22-acre site provides one of the last opportunities to create and enhance natural
habitat and improve ecological functions within the rapidly developing Lower Green
River Valley. Channelization of Springbrook Creek, past agricultural practices, and
recent build -out of the area have dramatically altered hydrologic regimes, increased
impervious surface, and removed native vegetation over the majority of the surrounding
landscape. This will be one of the first urban mitigation banks in Washington State, and
upon certification will serve as a model project for establishing mitigation banks in
similar urbanized areas.
Springbrook Bank meets the following site -selection criteria supported by the WSDOT
CBMOA (1994), listed in order of preference:
1. A site where one or more of the three criteria used to determine if a site is a
wetland (i.e., hydrophytic vegetation, hydric soils, and wetland hydrology),
especially wetland hydrology, have been completely lost and can be restored
(Units C and E).
2. A site where one or more wetland functions and values have been eliminated
by prior human activity and can be restored to their previous type, size, and
vigor (Units A, B, C, and E).
3. A site where wetland functions and values have been severely degraded by
prior human activity and can be enhanced to their previous type, size, and
vigor (Units A, B, C, and E).
4. A site that is not a wetland, but where a wetland can be created that is adjacent
to and has high potential to complement existing wetlands. Examples include
areas adjacent to existing riparian corridors, Washington Natural Heritage
Sites, Washington State Wildlife Areas, and National Wildlife Refuges (Units
C and E).
5. A site that is not wetland, but where a wetland can be created (Units C and E).
6. A site where development, management, and maintenance could appropriately
enhance one or more existing wetland functions and values (Units A, B, C,
and D).
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Opportunities for successful restoration at Springbrook Bank are high for the following
reasons:
1. The proposed restoration strategy focuses on re-establishing ecological
conditions and functions historically provided at or near the site.
2. The Springbrook Creek riparian corridor, surrounding mitigation sites, and
adjacent railroad tracks provide excellent "corridors" for wildlife movement.
3. Activities will improve fish and wildlife habitat in a watershed where it has
been severely degraded.
Ecological restoration activities at Springbrook Bank will address factors that currently
limit aquatic habitat functions in the Springbrook Creek sub -basin and downstream areas,
such as lack of fish -rearing and refuge habitat, degraded water quality,
hydromodification, and lack of native riparian vegetation (Kerwin and Nelson 2000;
WRIA 9 Steering Committee 2005). Opportunities to provide these habitat
improvements in the Lower Green River Basin are limited by development pressures and
water -conveyance concerns.
1.1.4 Bank Site Description
1.1.4.1 Historic Condition
The five units, which make up Springbrook Bank, are located in the Eastern Puget
Riverine Lowlands Ecoregion (EPA 2002) on a relatively level valley floor. The King
County Soil Survey (Snyder et al. 1973) states that soil types on the Springbrook Bank
site are associated with streams and river valleys that naturally support herbaceous
species, such as grasses and sedges, and a variety of forest types, with dominant trees
such as Douglas fir, western hemlock, Sitka spruce, western red cedar, red alder, big -leaf
maple, black cottonwood, and willow. A 1940 aerial photo (Figure 1-4) shows
Springbrook Creek being channelized by the mid-1930s with remnants of the original
stream alignment present within the boundaries of Units C and E (Puget Sound River
History Project 2005).
1.1.4.2 Baseline Conditions
The baseline conditions for each mitigation unit at Springbrook Bank are described
below. For purposes of this Instrument, Units A and B are described together because
they are ecologically similar, and both adjacent to Springbrook Creek and one another.
Units A and B
Units A and B encompass 62.5 acres, of which 55.5 acres are currently wetland (WSDOT
2005a) (Figures 1-5 and 1-6).
Hydrology: Springbrook Creek flows within a straight, bermed corridor between Units A
and B. Precipitation, groundwater, and surface water runoff from off -site tributary areas,
adjacent roads, and developments are the primary sources of existing hydrology. The
berms along Springbrook Creek disconnect the creek from its wetland floodplain, except
during extreme flood events. A small ditch exists in the northeastern portion of Unit B
and is the only existing connection between Unit B and Springbrook Creek. A ditch
along the southern property line in Unit A collects stormwater from the development to
the south and directs flows to Springbrook Creek. This is the only existing connection
between Unit A and Springbrook Creek.
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Vegetation: Areas closest to the creek have substantial native woody cover consisting
primarily of Pacific willow (Salix lucida), Sitka willow (Salix sitchensis), some black
cottonwood (Populus balsamifera), and red alder (Alnus rubra) in slightly drier areas.
Areas farther from Springbrook Creek are dominated by reed canarygrass (Phalaris
arundinacea) and cattail (Typha latifolia and Typha angustifolia) with patchy woody
cover provided by willow species. Reed canarygrass dominates the riparian areas on the
berms directly adjacent to Springbrook Creek. General vegetation communities are
shown in Figure 1-10.
Unit C
Unit C encompasses 47.7 acres, of which 27.1 acres are currently wetland (WSDOT
2005a) (Figure 1-7).
Hydrology: Existing hydrology in Unit C is provided by a combination of precipitation
and elevated groundwater. A conveyance ditch entering the site from the Burlington
Northern Santa Fe (BNSF) property to the south does not currently provide direct surface
hydrology to the majority of wetlands in Unit C but provides hydrology to a narrow
corridor along the ditch.
Vegetation: Non-native grasses, common tansy (Tanacetum vulgare), and Himalayan
blackberry (Rubus armeniacus) currently dominate the proposed Wetland Re -
Establishment Area. Black cottonwood, red alder, Pacific willow, Sitka willow, and red -
osier dogwood (Corpus sericea) mixed with Himalayan blackberry currently dominate
portions of existing wetlands and uplands at the site. Large areas of reed canarygrass and
patchy native shrub cover dominate the majority of the site closest to the BNSF right of
way. Along the eastern edge of the site adjacent to Oakesdale Avenue, disturbance -
tolerant grasses and forbs predominate including: common tansy, lance -leaf plantain
(Plantago lanceolata), teasel (Dipsacus sylvestris), and bull thistle (Cirsium vulgare).
General vegetation communities are shown on Figure 1-10.
Unit D
Unit D encompasses 4.7 acres, all of which is currently wetland (WSDOT 2005a)
(Figure 1-8).
Hydrology: A shallow inundated area occurs on the northern portion of Unit D. The
inundated emergent area and the forested wetland appear to be supported by
precipitation, seasonally high groundwater, and surface water connections from wetlands
west of the BNSF mainline. A culvert connects the wetlands west of the railroad track to
the inundated area. The entire site discharges to the north, via a culvert under an existing
BNSF rail line and an existing conveyance ditch to Unit C (see figure 2-4).
Vegetation: Red alder, black cottonwood, Pacific willow, and Oregon ash (Fraxinus
latifolia) make up the forest canopy. The shrub layer includes salmonberry (Rubus
spectablis), red -osier dogwood, and hardhack (Spirea douglasii). A few minor patches of
Himalayan blackberry are present in the upland and wetland forest understory and open
areas in this unit. Reed canarygrass dominates several areas of the existing wetland.
Cattails, reed canarygrass, and mild waterpepper (Polygonum hydropiperoides var.
hydropiperoides) predominate in the inundated area at the northern end of the site.
General vegetation communities are shown on Figure 1-10.
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Unit E
Unit E encompasses 14.8 acres, none of which is currently wetland (WSDOT 2005a)
(Figure 1-9).
Hydrology: No wetland hydrology currently exists at Unit E.
Vegetation: Sections of the site are dominated by black cottonwood forest with
Himalayan blackberry in the understory. Large portions of the site have been impacted
by off -road vehicle use and are dominated by non-native grasses, common tansy, and
Himalayan blackberry. General vegetation communities are shown on Figure 1-10.
1.1.4.3 Soils
The King County Soil Survey maps four soil types at the Springbrook Bank site: Puget
silty clay loam, Puyallup fine sandy loam, Snohomish silt loam, and Woodinville silt
loam (Snyder et al. 1973). The Puget, Snohomish, and Woodinville series are listed as
hydric soils (NRCS 2001).
In wetland re-establishment areas proposed in Units C and E, analysts examined soils
taken from geotechnical borings. The soil samples consisted of sandy gravel and sand to
silty sand (fill), interbedded sand and silt underneath the areas of fill, then lower
permeability silts and silty sands, and poorly graded sand to silt at the bottom of the soil
borings. Peat was also intermixed and discovered in many of the soil layers (Hart
Crowser 2005a). Geotechnical borings were also conducted in Unit A along the proposed
trail alignment to help inform trail design. These investigations found a top layer of silt
to sandy silt with scattered organic material along the berm. Underneath the top layer
along the berm and near the surface in other portions of the site lies a layer of organic silt
and peat, which contains fibrous peat in the upper portion, a layer of soft gray plastic silt,
underlain with a layer of silty sand at the bottom of the borings (Hart Crower 2005b).
1.1.4.4 Wetlands
The Springbrook Bank site contains 88 acres of jurisdictional wetland (Figures 1-5
through 1-9). Each wetland was delineated using the Washington State Wetlands
Identification and Delineation Manual (Washington State Department of Ecology 1997)
and was subsequently rated using the City of Renton Wetland Rating System (Renton
2005). Category I wetlands are of the highest quality while Category IV wetlands are
severely degraded and hydrologically isolated. Two wetlands - all of Unit D and portions
of Unit C, totaling 26.8 acres - were rated as Category II. Six remaining wetlands - Units
A and B and portions of Unit C, totaling 62.2 acres - were rated as Category III (WSDOT
2005a).
In fall and winter 2004, the Method for Assessing Wetland Functions Volumes I and 2
(WFAM) (Hruby et al. 1999) was used to assess functions and values of the existing
wetlands. The WFAM method measures on -site indicators of various wetland functions
producing numerical indices. These indices only address a wetland's potential to provide
assessed functions, and are therefore, only relevant when comparing wetlands of the same
hydrogeomorphic (HGM) class that share similar opportunities to perform specific
functions. This assessment method is based on the HGM approach, described by Brinson
(1993) and Smith et al. (1995). An HGM class is determined primarily by landscape
position, topography, and source of hydrology. The two HGM classes identified within
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the site are riverine and depressional. The riverine wetlands present in Units A and B
currently function similarly to depressional wetlands, due to the berms isolating
Springbrook Creek from its floodplain.
The principal functions of the riverine wetlands include; flow attenuation; reduction of
downstream erosion; and removal of excess sediment, nutrients, and metals. The
remaining depressional wetlands provide low levels of habitat functions and lack
significant hydrologic and water quality functions due to their relative isolation from
other wetlands/water sources. These wetlands also have an absence of vegetative and/or
habitat diversity.
1.1.4.5 Habitat and Wildlife Use
There is no high quality stream habitat present on or adjacent to the Springbrook Bank
site. Springbrook'Creek runs parallel and adjacent to three of the five units (Units A, B,
and E). Springbrook Creek is characterized by rapid short -duration responses to rainfall
events, high sediment loads, high temperatures, and low dissolved oxygen levels.
Additionally, riffles, pools, and large woody debris are absent from the creek, providing
little habitat for salmonids. Woody riparian vegetation is particularly lacking in the reach
of Springbrook creek adjacent to Units A and B. The lower reach of Springbrook Creek
(north of the bank site) is suitable for juvenile salmonid rearing and migration. However,
spawning is unlikely in the creek due to the low gradient and lack of appropriate gravel
substrate. Steelhead (Oncorhynchus mykiss), cutthroat trout (Salmo clarki), Chinook
salmon (Oncorhynchus tsawytascha), Coho salmon (Oncorhynchus kisutch, and lamprey
(Lampetra sp.) have been documented in Springbrook Creek (Kerwin and Nelson 2000;
Harza 1995). Coho salmon were stocked in the creek from the mid 1970s until 2004
(WSDOT 2005d). The current configuration of the creek and adjacent berms in Units A
and B creates a low potential for fish standing during flood events (WSDOT 2006).
Currently one small outlet is present in both Units A and B for fish to enter and/or escape
from onsite wetlands.
The creek acts as a wildlife corridor connecting the various higher quality habitats along
its length, such as the Black River Riparian Forest to the north (Figure 1-1). The railroad
right of way also serves as a wildlife corridor, connecting habitats and wildlife south of
Springbrook Bank (Units C and D are adjacent to the BNSF rail line). Coyote, red-tailed
hawks, and other raptors have been observed at the bank. The bank is also used by great
blue herons that nest at the Black River Riparian Forest. This heron nesting colony is one
of the largest in the Puget Sound Area, with over 120 occupied nests being observed in
recent years (Seattle Audubon 2005). No signs of deer or other large mammal use have
been observed at the bank.
1.1.5 Unique Urban Setting and Public Access
This section describes the unique urban setting of Springbrook Bank that creates a basis
for including a public access trail.
1.1.5.1 Reasons for Including a Trail at Springbrook Bank
The trail will provide the critical missing link that has been incorporated in the long-term
planning for the local and regional trail systems:
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• The City of Renton made formal commitments to the community to connect the
trail system at this location long before the site was proposed as a mitigation
bank. The City previously acquired an easement as part of a long-range trail
linkage planning effort in the Springbrook Creek area through the City of
Renton's Parks, Recreation, and Open Space Plan and Trails Master Plan
(adopted June 1992).
• The proposed trail will connect to the existing trail that runs through the Green
River Valley and then connects to a larger, regional trail system - King County's
regional Interurban Trail and King County's regional Green River Trail.
Disturbances due to the urban setting and surrounding land uses will minimize wildlife
impacts from the trail:
• Due to the densely urbanized setting and surrounding local land uses, wildlife that
may use the bank site has adapted to an urban setting through the exposure to a
high level of human activity in the project vicinity. Any disturbance related to the
presence of the trail would be minor compared to existing disturbances from the
surrounding urban landscape.
The public expects access to large publicly owned urban natural areas:
• Substantial state resources and City lands will be used to develop Springbrook
Bank, which will be established in a highly urbanized ecosystem and develop
connections between people and local natural resources.
• Springbrook Bank will conserve 129.22 acres of some of the last remaining large
tracts of undeveloped green space in the Lower Green River Basin.
The trail will provide substantial environmental education opportunities to an urban
community:
• The unique urban setting of Springbrook Bank, the City's planned trail access,
and the relative lack of natural areas in the project vicinity present a rare
opportunity to integrate environmental education, public access, and wetland
mitigation. Maximizing this opportunity will increase opportunities for awareness
and understanding of the important ecosystem functions that wetlands, streams,
and riparian areas provide within an urbanized setting.
• By placing the trail near Springbrook Creek, the public will see a diverse
environment with connections to wetlands and streams.
• Educational opportunities provided by the trail will help maximize environmental
benefits for the community through education, which may result in public support
for funding environmental mitigation and stewardship activities in the region.
• Education and public involvement are vital parts of natural resource management.
The importance of education and public involvement is demonstrated by its
inclusion and emphasis in Green Infrastructure planning, Alternative Futures
analysis, and the development of comprehensive plans. Education is essential
because it provides the public with an accurate understanding of why natural
resources are valuable to the community. Education and outreach efforts are also
key factors to increasing enrollment in incentive programs that foster land
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conservation. Likewise, these efforts also encourage the public to get involved
through voluntary actions either on their own property or by supporting local
projects. Education and public involvement can also improve support for
regulatory protection. (This text was adapted from Wetlands in Washington State
— Volume 2: Guidance for Protecting and Managing Wetlands [Washington State
Department of Ecology 2005]).
1.1.5.2 Selection of Proposed Trail Alignment
Selection of a trail alignment was a process that incorporated a number of environmental
and social factors. The following criteria were used to select the proposed trail
alignment:
• Align the trail as directly as possible on City -owned property.
• Minimize impacts to wetlands, woody vegetation, and riparian areas.
• Maximize alignment through existing invasive vegetation.
• Incorporate environmental education within a wetland setting.
• Complete the missing link of an existing trail as planned in accordance with the
City's Master Trail Plan and the King County Regional Trail System.
The trail alignment that best meets the selection criteria for Springbrook Bank includes
an elevated, eight -foot -wide public boardwalk trail, limited to pedestrian use, located near
the western edge of Unit A, and roughly parallel to Springbrook Creek. The elevated
boardwalk will connect to the local and King County regional trail systems. Benches will
be placed at two locations along the trail to promote passive recreation, such as bird
watching (see figure 2-2). The trail and a 40-foot-wide vegetated buffer on each side will
not generate mitigation credits (see Section 2.6.1.4 "Trail Zone" for more details).
Advantages of the proposed trail alignment include:
• No mitigation credits will be generated from an 88-foot "Trail Zone," which
encompasses the trail itself and 40 feet on both sides of the trail to account for any
disturbance to the site and/or wildlife that may result from the trail presence and
use. Removing invasive weeds and planting native trees and shrubs will
rehabilitate wetlands within this zone.
• The footprint of the trail will be approximately 11,000 square feet (1,365 feet long
by eight feet wide), which will affect approximately 0.25 acre of the 26 acres in
Unit A. This footprint is much smaller than other City trails, which are typically
12 feet wide.
• Constructing the trail as part of Springbrook Bank will allow the remaining
25 acres of Unit A to be restored and protected in perpetuity. The trail will not
affect the 105 acres of Springbrook Bank in Units B, C, D, or E.
• The City will convert the section of the trail running through the Springbrook
bank from a mixed -use trail (as originally planned) to a pedestrian -only trail
minimizing human disturbance to wildlife habitat, while offering higher quality
birding and other educational opportunities to the pedestrian.
• The City will restrict bicycle use on the section of the trail within Springbrook
Bank, limiting disturbance to wildlife. The City has existing bike routes
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established in the area. Adequate signage will be posted to direct cyclists to the
established bike routes.
Aligning the trail generally along the most direct route reduces the potential for
unauthorized "shortcut" trails through Unit A. Users are likely to deviate from
"authorized" circuitous routes if there is a more direct route.
Impacts to wetlands and woody vegetation from a shorter, more direct trail route
are estimated to be less than longer routes.
Several alternative trail alignments were also considered but were rejected because they
did not satisfy the selection criteria for a trail alignment. These alternative trail options
and the reasons for rejecting them are summarized below.
Unit A Perimeter Option —This option aligns the trail within the southern, eastern, and
northern perimeter buffer of Unit A. This option was rejected because it created a longer
alignment that would have resulted in substantially greater impacts to wetlands and
woody vegetation than the selected trail alignment.
Unit A Interior Option —This option includes a trail that broadly bends through the
interior of Unit A. This option was rejected because it created a longer alignment that
would have resulted in substantially greater impacts to woody vegetation than the
proposed trail alignment, and would essentially bisect Unit A and disturb the interior.
Unit A Berm Option —This option aligns the trail on the berm next to Springbrook
Creek. This location was identified in the City of Renton Trails Master Plan (1992) and
is consistent with the alignment of existing segments of the Springbrook Trail located
adjacent to Springbrook Creek, and within the City's existing Greenbelt easement. This
option was rejected because it would directly affect riparian functions by disturbing some
existing riparian trees and limit future establishment of riparian trees. Impacts to riparian
conditions are undesirable because Springbrook Creek is limited by water quality
problems, such as high water temperature and low dissolved oxygen.
Oakesdale Avenue Option —This option aligns the trail west along SW 34th Street,
north along Oakesdale Avenue SW, and east along 27th Street SW. This option was
rejected for a number of reasons. This alignment is indirect and much longer, it would
expose the public to safety risks associated with street traffic, it would abandon a portion
of Springbrook Trail that already extends to the southern boundary of Unit A, it would
not provide suitable environmental education opportunities in a wetland setting, and it
would be inconsistent with the City's Trails Master Plan (1992).
No Trail Option —This option is rejected (if funding is available to build the trail)
because it would not establish the missing link to the existing Springbrook Trail, and
would be inconsistent with the City's Trails Master Plan (1992). The City specifically
acquired a portion of the property within Springbrook Bank for use as a trail.
1.2 LEGAL AUTHORITY AND RESPONSIBILITIES OF BANK
SPONSOR AND PARTNERS
Springbrook Bank will be established in accordance with the following federal and state
statutes, regulations, guidelines, and policies:
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• Clean Water Act (33 USC 1251 et seq.)
• Rivers and Harbors Act of 1899 (33 USC 401, et seq.)
• Regulatory Programs of the Corps of Engineers (33 CFR Parts 320-330)
• Guidelines for the Specification of Disposal Sites for Dredged and Fill Material
(404(b)(1) Guidelines, 40 CFR Part 230)
• Memorandum of Agreement Between the Environmental Protection Agency and
the Department of the Army Concerning the Determination of Mitigation Under
the Clean Water Act Section 404(b)(1) Guidelines (February 6, 1990)
• U.S. Army Corps of Engineers Regulatory Guidance Letter 05-1, Guidance on the
Use of Financial Assurances, and Suggested Language for Special Conditions for
Department of Army Permits Requiring Performance Bonds, (February 14, 2005)
• Federal Guidance for the Establishment, Use, and Operation of Mitigation Banks
(November 28, 1995)
• National Environmental Policy Act (42 USC 4321 et seq.)
• Magnuson -Stevens Fisheries Conservation and Management Act (16 USC §§
1801 et seq.)
• Coastal Zone Management Act (16 USC 1451, et seq.)
• Council on Environmental Quality Procedures for Implementing the National
Environmental Policy Act (40 CFR Part 1500-1508)
• Executive Order 11988 (Protection of Floodplains)
• Executive Order 11990 (Protection of Wetlands)
• Executive Order 13112 (Invasive Species)
• Fish and Wildlife Coordination Act (16 USC 661 et seq.)
• Fish and Wildlife Service Mitigation Policy (46 FR 7644-7663, 1981)
• Endangered Species Act (16 USC 1531 et seq.)
• National Historic Preservation Act, as amended (16 USC 470)
• Washington State Environmental Policy Act (`SEPA'RCW 43.21C and
WAC 197-11)
• Growth Management Act (RCW 36.70A) and Critical Areas Regulations "Best
Available Science" (WAC 365-195-900 to 925)
• Washington State Water Pollution Control Act (RCW 90.48)
• Washington State Hydraulic Code (RCW 75.20)
• Washington State Shoreline Management Act (RCW90.58, WAC 173-200) as
amended
• Washington State Salmon Recovery Act (RCW 75.46)
• Washington State Aquatic Resources Act (RCW 79.90, RCW 90.74)
• Washington State Alternative Mitigation Policy, developed by Ecology,
Washington State Department of Transportation, Washington State Department of
Fish and Wildlife, and the Office of Community Development, 2000
• Wetland Mitigation Banking (RCW 90.84)
• Washington State Draft Rule on Wetland Mitigation Banking (WAC 173-700)
• City of Renton Critical Areas Ordinance (Ordinance number 5137)
Nothing in the Instrument shall be construed as altering the requirements and agency
responsibilities as specified in existing law, regulation, and policy.
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1.2.1 WSDOT Memorandum of Agreement and the Bank Oversight Committee
WSDOT entered into a Memorandum of Agreement for wetland banking with state and
federal wetland regulatory agencies in 1994. The Washington State Department of
Transportation Wetland Compensation Bank Program Memorandum of Agreement
(CBMOA) (WSDOT 1994) provides the principles and procedures for establishing,
implementing, and managing WSDOT wetland mitigation banks. Signatories to the
WSDOT CBMOA include U.S. Army Corps of Engineers (Corps), U.S. Environmental
Protection Agency (EPA), U.S. Fish and Wildlife Service (USFWS), U.S. National
Marine Fisheries Service (NMFS), Federal Highway Administration (FHWA),
Washington State Department of Ecology (Ecology), Washington State Department of
Fish and Wildlife (WDFW), and WSDOT.
The WSDOT CBMOA establishes a Bank Oversight Committee (BOC) to review and
approve WSDOT mitigation bank proposals. WSDOT is responsible for convening and
facilitating meetings of the committee. The BOC members for Springbrook Bank are
comprised of representatives from the Corps (Chair), EPA, USFWS, Ecology (Chair), the
City of Renton, and WSDOT. The BOC member agencies are the signatories of the
Springbrook Bank Instrument. The BOC meetings provide a venue for project review
and coordination between WSDOT and the various state, federal, and local governments.
The BOC members review and comment on all phases of WSDOT bank site
development. The Corps, Ecology, and various local governments are the potential
permitting agencies with jurisdictional authority. When credits are to be withdrawn from
the bank, the agencies with jurisdiction will coordinate the debiting of credits and the
BOC members will see these debits reflected in the annual ledger.
1.2.2 Responsibility of WSDOT and City of Renton
As between the two Sponsors, WSDOT is responsible for development, design,
permitting, and construction of the Springbrook Bank. The City is providing the land for
the Bank in perpetuity and the funding for trail design and construction. WSDOT will be
the lead agency for the establishment phase of the Bank. The City will be the lead
agency for the long-term management phase of the Bank, which will commence at the
termination of the establishment phase. WSDOT will prepare and distribute monitoring
reports required during the establishment phase, and maintain and submit the primary
accounting ledger to satisfy the BOC's requirements and comply with the CBMOA. The
City may maintain its own separate concurrent ledger to track its portion of the credits,
but WSDOT will retain responsibility for the master ledger detailing all debits and credits
associated with Springbrook Bank.
1.3 SERVICE AREA
The service area of Springbrook Bank includes portions of WRIAs 8 and 9, which
includes the Lower Green River, Black River, West Lake Washington, East Lake
Washington, May Creek, Mill Creek Basins, and the Lower Cedar River Basin to SR 18
(Figure 1-3). Portions of the Lower Cedar River Basin southeast of SR 18 have been
excluded from the service area because it extends over 7 miles into less urbanized areas.
The following listed criteria were taken into account in defining the service area of
Springbrook Bank and are based on criteria outlined in the CBMOA (WSDOT 1994),
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Federal Guidance for the Establishment, Use, and Operation of Mitigation Banks
(US Army Corps of Engineers 1995), and the Washington State Draft Rule on Wetland
Mitigation Banking (Washington State 2001).
1. Springbrook Bank will improve wetland and stream functions. The bank will
restore, enhance, and protect watershed processes that create improved wildlife
habitat, riparian and floodplain functions, and water quality in an area with little
natural space left.
2. Springbrook Bank is very low in the watershed. By including sub -basins lower in
WRIAs 8 and 9, Springbrook Bank will serve as mitigation for wetland impacts much
closer to the project areas of proposed projects and within Renton city limits rather
than farther away, but within the same WRIA.
3. Similar Ecoregion. The service area includes basins in a similar ecoregion, in which
the remaining ecological systems are relatively uniform within a nearly built -out
urban area. Springbrook Bank is designed to function at full watershed build -out to
increase its sustainability in a highly urbanized watershed.
4. Watershed -Based Mitigation. The overall ecological benefit of an urban bank
exceeds the value of alternatives, which would likely involve the creation of small
wetland fragments along the highway right of way as compensation for impacts to
small Category II, III, and IV wetlands.
5. WSDOT and City of Renton. The credits available to WSDOT from the bank will
be used for mitigation of transportation projects in the service area. The credits
available to the City will be used for City -approved projects within the service area.
6. WSDOT's Water Resources Program. Springbrook Bank and the Early
Environmental Investments (EEI) Program are components of a larger water
resources program that includes avoiding and minimizing water resource impacts,
onsite stream mitigation where feasible, and other watershed solutions. Springbrook
Bank is one of several alternatives for water resource improvement opportunities for
WSDOT.
Projects located within the service area (Figure 1-3) are eligible for use of credits from
Springbrook Bank for mitigation according to the terms of this Instrument. Projects
outside of the service area will only be eligible in limited circumstances where
practicable alternatives do not exist and with special approval of the Corp and Ecology
following consultation of the other BOC members.
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1.4 REQUIRED PERMITS AND APPROVALS
Environmental documentation and permits required for this project are summarized in
Table 1-1 and described below. WSDOT and the City commit to receiving the required
approvals prior to beginning site construction, and cannot proceed without receiving the
approvals listed below.
Table 1-1. Permit Activities and Environmental Documentation
Perm itlConcurrence Letter
Agency
Section 404 Individual Permit (IP)
Corps
Section 401 Individual Water Quality Cert.
Ecology
Section 402 NPDES Permit
Ecology
CZMA Consistency Determination Letter
Ecology
Hydraulic Project Approval (HPA)
WDFW
ESA Concurrence Letter
USFWS
ESA Concurrence Letter
NMFS
EFH Concurrence Letter
NMFS
Shoreline Substantial Development Permit
City of Renton
Critical Areas Approval
City of Renton
Floodplain Permit
City of Renton
Public Works Construction Permit
City of Renton
Section 106 Concurrence Letter
DAHP
Environmental Documentation
Date Completed
Wetland Biology Report
May 2005
SEPA Determination of Non Significance (DNS)
January 2006
Biological Assessment
March 2006
Section 106 Cultural Resources Concurrence
January 2006
Springbrook Bank Prospectus
February 2006
Joint Aquatic Resources Permit Application (JARPA)
January 2006
Public Notification
Date Issued
SEPA Public Notice
January 2006
General Construction NPDES Permit
April 2006
Corps 404, Ecology 401, and CZMA Joint Public Notice
March 2006
SMA Public Notice — local governments
March 2006
1.4.1 Section 404 Permit
The Corps will require a Section 404 Individual Permit (IP) for this project. As part of
the Section 404 permit process, the project will obtain approvals for or demonstrate
compliance with the Endangered Species Act, Magnuson -Stevens Act, National Historic
Preservation Act, Clean Water Act, Coastal Zone Management Act, and the National
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Environmental Policy Act. The Section 404 IP will contain permit conditions specific to
the Springbrook Bank project, some of which may be contained within this Instrument.
1.4.2 Section 401 Water Quality Certification
A Section 401 Individual Water Quality Certification (WQC) will be required for tills
project by the Washington State Department of Ecology (Ecology).
1.4.3 Section 402 NPDES Permit
A Section 402 General National Pollutant Discharge Elimination System (NPDES) will
be required for this project by the Washington State Department of Ecology (Ecology).
1.4.4 CZMA Consistency Determination
A Coastal Zone Management Act (CZMA) Consistency Determination Letter will be
required for this project by the Washington State Department of Ecology (Ecology).
1.4.5 Hydraulic Project Approval
A Hydraulic Project Approval (HPA) for this project was issued by the Washington
Department of Fish and Wildlife on April 24, 2006.
1.4.6 Endangered Species Act Biological Assessment
WSDOT prepared a Biological Assessment (BA) to address the potential effects of the
Springbrook Bank project on species listed under the Endangered Species Act (ESA).
Listed species in the vicinity of the project include Coastal -Puget Sound bull trout
(Salvelinus confluentus), designated bull trout critical habitat, bald eagle (Haliaeetus
leucocephalus), Puget Sound Chinook salmon (Oncorhynchus tshawytscha), and
designated Chinook salmon critical habitat. After a thorough species effects analysis,
WSDOT has determined that the project may affect, but is not likely to adversely affect
(NLAA) bull trout, designated bull trout critical habitat, Chinook salmon, and designated
Chinook salmon critical habitat. The determination for bald eagles is no effect (NE). The
potential effects to listed species will be minimized through the use of specific best
management practices and conservation measures identified in the BA (WSDOT 2006).
The project received Concurrence Letters from the National Marine Fisheries Service
(NMFS) on March 20,2006 and from.USFWS on May 5, 2006.
Every six months during construction, WSDOT will review the project activities as
described in the Biological Assessment and review the updated WDFW Priority Habitat
and Species data to ensure that the original consultation is still valid. If, prior to project
completion, new species are listed or new listed species move into the project area,
WSDOT is prepared to reinitiate consultation with USFWS and/or NMFS.
WSDOT also evaluated potential project impacts to Essential Fish Habitat (EFH) as
required by the Magnuson -Stevens Act. After a thorough effects analysis, WSDOT has
determined the Springbrook Bank project will have no adverse effect on EFH. NMFS is
expected to issue a Concurrence Letter with this determination.
1.4.7 Shoreline Substantial Development Permit
As required by the Shoreline Management Act (SMA), a Shoreline Substantial
Development Permit (SSDP) will be required by the City of Renton for this project. As
MBI Ch1 Intro_050806.doc
Chapter 1 May 2006
Introduction and Background Page 1-16
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
part of the SSDP review process, which includes a critical areas and land use review, the
City of Renton, is expected to issue its regulatory approval of Springbrook Bank.
1.4.8 National Historic Preservation Act, Section 106 Compliance
A cultural resources survey was conducted to identify and determine the probability of
archaeological resources and traditional cultural places in the project area. The survey
revealed that there is a low probability for historic period archaeological deposits to occur
and that no traditional cultural places exist at the bank site (HRA Cultural Resources
2005). However, excavation will be monitored, especially within the vicinity of an
isolated find that included a hunter -fisher -gatherer artifact recovered during a field visit.
Construction monitoring will occur in accordance with the Springbrook Creek Habitat
and Wetland Mitigation Bank Project, Cultural Resources Discipline Report (HRA
Cultural Resources 2005). WSDOT received a Concurrence Letter from the Department
of Archaeology and Historic Preservation (DAHP).
1.4.9 Other Approvals
As required by the State Environmental Policy Act (SEPA), a Determination of Non -
Significance (DNS) will be issued by WSDOT.
The Corps will review the project for compliance with NEPA as documented within the
Corps federal decision document for Individual Permits.
M81 Ch1 Intro_050806.doc
Chapter I May 2006
Introduction and Background Page 1-17
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Springbrook Creek Wetland and Habitat Mitigation Bank
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
2.0 ESTABLISHMENT OF THE BANK
2.1 MITIGATION BANK PLAN OVERVIEW
The mitigation bank plan focuses on improving wetland functions within all five units of
Springbrook Bank and improving riparian functions in the three units adjacent to Springbrook
Creek (Figure 2-1). Mitigation construction work will include extensive site grading in Units C
and E; breaching the berms adjacent to Springbrook Creek in Units A, B, and E; treating reed
canarygrass and blackberry in Units A, B, and C; and installing habitat structures and planting
woody vegetation in all units. This work will improve a broad range of ecological functions to
increase wetland habitat, water quality, and hydrologic functions.
The mitigation plan is based on activities that occur in specific areas as shown in Figures 2-1
through 2-5 and defined as follows.
Wetland Re -Establishment Areas: Removal of historic fill material will facilitate the
re-establishment of former wetlands in Units A, B, C, and E. The excavation in Units A,
B, and E will remove sections of an existing berm in order to connect re-established
wetlands in these units with Springbrook Creek. Native trees, shrubs, and habitat
structures (vertical snags, brush piles, and/or large woody debris [I"]) will be installed
at Units C and E. These activities will restore wetland area, function, and value where
historic wetlands previously existed.
Wetland Rehabilitation Areas: Improving the hydrologic regime of existing wetlands
will facilitate the rehabilitation of existing wetlands in Units A, B, and C. Reed
canarygrass monocultures will be mowed and treated with herbicide. Planting hummocks
will be installed in Units A and B to facilitate tree establishment, and provide additional
habitat niches and hydrologic regimes. Biologists concluded that breaching the berms in
Units A and B is expected to reduce the risk of fish stranding (WSDOT 2006). Native
trees, shrubs, and habitat structures will be installed in Units A, B, and C to increase
species diversity, habitat structure and habitat complexity.
Wetland Enhancement Type I Areas: Existing wetlands in Unit C will be enhanced by
increasing plant and habitat diversity in large areas of invasive non-native vegetation
(reed canarygrass and Himalayan blackberry) through a combination of several activities:
implementation of aggressive reed canarygrass and blackberry control measures; dense
planting of native trees and shrubs; and placement of habitat structures. These activities
will increase species diversity and habitat structure and complexity.
Wetland Enhancement Type II Areas: Supplemental hydrology will be provided to
existing seasonally inundated areas in the northern portion of Unit D. The additional
water will be redirected from a stormwater/groundwater management facility
(constructed as part of the South 180th Grade Separation Project) at the southern edge of
Unit D and then transported via a new conveyance pipe from a treatment pond to the
northern end of the unit. Additional hydrology will extend existing hydrologic regimes.
Forested Wetland Enhancement Areas: Native coniferous trees will be under -planted
in the existing forested wetland portions of Units C and D. This will require the removal
of invasive non-native vegetation from the understory in portions of Springbrook Bank.
Under -planting conifers will enhance species and structural diversity in both units.
Chapter 2 May 2006
Establishment of the Bank Page 2-1
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Upland Habitat Enhancement Areas: Removing invasive non-native vegetation,
installing habitat structures, under -planting upland deciduous forests with native
coniferous trees, and densely planting native woody species will enhance upland habitats
in Units C.
Riparian Upland Enhancement Areas: Establishing riparian vegetation through a
combination of mowing and herbicide treatment of reed canarygrass, selectively
removing other invasive non-native vegetation, and planting native trees and shrubs will
increase riparian functions along Springbrook Creek in Units A, B, and E. This treatment
is limited to berms adjacent to Springbrook Creek in Units A, B, and E and uplands
adjacent to the wetland re-establishment areas in Unit E.
Protection Setback (Buffer): Portions of all units, except Unit D, will include 40-foot-
wide "buffers'? to be planted with native trees and shrubs in both wetlands and uplands.
This will promote structural diversity and protect habitat from disturbance from adjacent
land uses. This area will not generate wetland mitigation credits.
Trail Zone: A Trail Zone in Unit A will include an 8-foot-wide trail and a 40-foot-wide
protection setback area on both sides of the proposed trail. This will create a 2.66-acre
area (88-foot wide by 1,365-foot long) that will not generate mitigation credits. In order
to construct the trail, existing vegetation within an 18-foot-wide temporary construction
corridor will be cleared, the 8-foot-wide trail constructed, and all the areas not occupied
by the trail replanted with native woody vegetation. Areas within the Trail Zone
dominated by reed canarygrass will be mowed, treated with herbicide, and planted as part
of the overall wetland rehabilitation treatment in Unit A.
2.2 CONSTRUCTION SCHEDULE
The wetland re-establishment areas in Units C and E, berm breaches in Units A and B, and a
small portion of the wetland rehabilitation area in Unit C (to match existing topography) will be
excavated and soils amended during the first construction season. Control of reed canarygrass
will also begin during the first construction season. Woody plantings in all units, except portions
of Unit E, will be installed during the first fall and winter planting season. If necessary, planting
of flood -prone areas with containerized plant materials may be delayed until early spring. Large
woody debris, snags, and brush piles will be installed during and/or after site grading has been
completed.
A phased construction schedule will be implemented at Unit E. In the first year of construction,
the site preparations and erosion control measures will be installed, and all of the area behind the
30-foot-wide berm will be excavated and planted. In the following summer, the breaches in the
berm will be excavated, and the entire berm and breaches will be planted. Springbrook Creek
will be allowed to enter Unit E in the fall of the second construction season.
As -Built plans documenting post -construction site conditions will be submitted to the BOC
members within 90 days of project completion and will describe in detail any material deviation
from the applicable portion of the site plan. The as -built reports will also establish baseline
conditions for future monitoring
As -built reports will be submitted to the BOC upon the completion of grading and planting
activities to verify topography, hydrology, construction and planting. These reports will include
site topography, descriptions of planting, wetland and aquatic area boundaries, large woody
Chapter 2 May 2006
Establishment of the Bank Page 2-2
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
debris placement, designated photo points, groundwater monitoring wells, staff gauges, and other
pertinent data.
2.3 GRADING PLAN
Site grading will primarily be conducted to breach the berms in Units A, B, and E; re-establish
former wetlands in Units C and E; plug the existing conveyance ditch in Unit C; and install a
stormwater pipe to supplement hydrology to Units D and C. Grading work is shown on the
Grading Plans (Figures 2-10 through 2-13).
2.4 PLANTING PLAN
Vegetation species selection was based on native species known to occur in the project area that
will provide cover and value to wildlife, are flood -tolerant, and produce the greatest likelihood of
successful establishment. Tree plantings will include 18- to 36-inch containerized conifers and a
combination of 18- to 36-inch bare -root plants and/or containerized deciduous trees. Shrub
plantings will include a combination of 12- to 18-inch bare -root plants and/or containerized
stock, or 36-inch live -stakes for willow species. Table 2-1 provides a list of plant materials. The
Planting Plans (Figures 2-14 through 2-17) indicate the location of each area to be planted.
Chapter 2 May 2006
Establishment of the Bank Page 2-3
FINAL DRAFT
brook Creek Wetland and Habitat Mitigation Bank Instrument
Table 2-1. Master Plant Materials List
Wetland Tree/Shrub #1 wetter
Riparian Upland Plantings
Oregon ash Fraxinus latifolia
big -leaf maple Acer macro h llum
black twinber Lonicera involucrata
red alder Alnus rubra
Pacific ninebark Ph socar us ca itatus
Sitka spruce Picea sitchensis
black cottonwood Po ulus balsamifera
Douglas -fir Pseudotsu a menziesfi
Nootka rose Rosa nutkana
Scouler's willow Salix scouleriana
Sitka willow Salix sitchensis
snowber S m horicar os a/bus
Wetland Tree/Shrub #2 wettest
Upland Plantings
red -osier dogwood Corpus sericea
big -leaf maple Acer macro h llum
Oregon ash Fraxinus latifolia
serviceber Ame/anchier alnifolia
eafruit wild rose Rosa isocar a
beaked hazel (Corylus cornuta
Pacific willow Salix lucida
oceanspray Holodiscus discolor
Sitka willow Salix sitchensis
Douglas -fir Pseudotsu a menziesh
snowber S m horicar os a/bus
Wetland Tree/Shrub #3 wet
Hummock Plantings
red -osier dogwood Corpus sericea
Oregon ash Fraxinus latifolia
Sitka spruce Picea sitchensis
Pacific ninebark Ph socar us ca itatus
black cottonwood Po ulus balsamifera
Sitka spruce Picea sitchensis
Nootka rose Rosa nutkana
black cottonwood Po ulus balsamifera
Scouler's willow Salix scouleriana
western red cedar Thu'a licata
western red cedar Thu a licata
Wetland Forest Under -Plantings
Sitka spruce Picea sitchensis
western red cedar Thu'a licata
western hemlock Tsu a hetero h lla
Chapter 2 May 2006
Establishment of the Bank Page 2-4
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
2.5 WEED MANAGEMENT
A management strategy that promotes the long-term establishment of woody vegetation will be
applied at Springbrook Bank (Soll 2004). Weeds will be managed at Springbrook Bank in
accordance with King County Noxious Weed Law (King County 2005) and the Washington
State Noxious Weed List (Washington State Noxious Weed Control Board 2005) with additional
emphasis focused on reducing existing reed canarygrass (RCG), limiting additional RCG
establishment, and reducing the influence of Himalayan blackberry at the site. Estimated cover
of class A and B noxious weeds, RCG, and Himalayan blackberry will be reported during formal
monitoring, along with a record of management activities. Reed canarygrass cover will be
limited by high -density planting of native trees and shrubs, mulching immediately following soil
disturbance, and mowing and spraying RCG colonies to reduce competition and aid woody plant
establishment. In the long term, shade and competition from woody vegetation will act as a
natural RCG control. Himalayan blackberry will be controlled during initial construction,
actively managed over the operational life of the bank, and prevented from out -competing
planted native vegetation or dominating the site.
2.5.1 Existing Site Conditions Favor Reed Canarygrass
Eradication of reed canarygrass at Springbrook Bank is not practical. Variable hydrology, high
nutrient and sediment loads, and abundant upstream seed sources in the Springbrook Creek Basin
favor RCG colonization. These conditions will favor RCG growth regardless of the short-term
effectiveness of control efforts (Reinhardt and Galatowitsch 2004).
• Variable Hydrology - The hydrology in the Springbrook Creek Basin is highly variable,
which is driven by the high percentage of impervious surface in the basin. This results in
rapid high -stage, short -duration responses to rainfall events, large flood events, and low base
flows at varying times of year. Variable hydrology creates disturbance that favors RCG
growth (Kercher et al. 2004).
• High Nutrient and Sediment Loads - Flood events deliver large amounts of nutrients and
sediment to the sites because of the prevalence of urbanized landscapes upstream (Maurer et
al. 2003). High nutrient and sediment loads encourage rapid colonization and growth of
RCG (Miller and Zedler 2002; Mauer et al. 2003).
• Abundant Upstream Seed Sources - RCG is prevalent in wetlands and riparian areas
throughout the Springbrook Creek Basin where dense cover of woody vegetation is lacking.
Within the Bank site, RCG is dominant in the emergent portions of Units A and B, along
Springbrook Creek, and in the BNSF right of way in Unit C. Grading in Units C and E may
create conditions favoring RCG colonization in some areas.
2.5.2 Reed Canarygrass Offers Some Understory Functions
Reed canarygrass will likely be an understory component at Springbrook Bank, where it can
provide functional benefits. RCG provides several beneficial functions, including:
• Hydrologic Functions
- Surface roughness. The large size and dense growth habit of RCG slows surface water
velocities during flood events, decreases downstream erosion, and increases sediment
deposition.
- Stream bank stability. The dense root system of RCG resists erosion and develops
overhanging banks that provide habitat for fish and other aquatic species.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
• Water Quality Improvement Functions
- Surface roughness. The large size and dense growth habit of RCG slow surface water
velocities during flood events, and encourages sediment deposition.
- Nutrient and toxicant uptake. RCG takes up large amounts of dissolved nutrients and
toxicants due to its high annual biomass production compared to other herbaceous
species, and its tolerance of long duration inundation where it is exposed to high levels of
nutrients and toxicants in solution (Mauer et al. 2003).
• Fish Habitat
- Cover for juvenile coho. The growth habit of RCG provides cover and refugia for
juvenile coho during flood events. The ability of RCG to persist in standing water allows
it to provide coho rearing habitat in stream channels, backwaters, or ponded areas.
Malcom (1998) reported that the densities and sizes of over -wintering juvenile coho in a
reed canarygrass-dominated low -gradient stream (Mill Creek, King County, Washington)
were comparable to, and at times exceeded, those found in streams rated as having
superior habitat.
2.5.3 Strategy to Manage Reed Canarygrass
Because site conditions favor establishment of RCG and its presence is not entirely detrimental
to habitat, a management strategy that promotes the long-term establishment of woody
vegetation will be applied at Springbrook Bank. The strategy for managing RCG involves
mowing, herbicide treatment, and dense woody plantings. This strategy initially involves
mowing and spraying herbicide to suppress the existing RCG colonies in Units A, B, C, and E.
This approach is designed to create a window of opportunity and capture the site quickly to
prevent RCG from re-establishing. Long-term control of RCG at all the units will involve
densely planting native trees and shrubs, and spot -spraying RCG colonies with herbicides during
the monitoring period to ensure long-term success in establishing the desired woody plant
community. A short discussion of each phase of this process is provided below.
Mowing and Herbicide Treatment
• Mowing will occur as soon as the site is dry enough to allow access, but before seeds are
formed to decrease RCG height, reducing herbicide use and making herbicide treatment more
effective and efficient.
• Herbicide treatment, with chemicals specifically approved for aquatic use, will be conducted
in August and again in September while carbohydrates are being translocated from the
aboveground parts to the roots. This will provide the best possible control of belowground
roots and rhizomes (Antieau 1998; Tu 2004; Reinhardt and Galatowitsch 2004).
• Mowing and herbicide treatment will minimize soil disturbance. Both the available literature
and personal communications with experts have discouraged soil disturbance as a method of
RCG control because it exposes the existing seed bank to light triggering seed germination
(Clay Antieau 1998 and 2005; Susan Buis 2005; Monica Hoover 2005).
Mulch and Dense Woody Planting
• The herbicide treated RCG thatch will act as mulch in the short-term in the RCG removal
areas. Woody mulch will be used in areas of soil disturbance to deter the establishment of
RCG and other weeds and increase woody plant vigor.
Chapter 2 May 2006
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FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
• Plantings will consist of deciduous woody species that are flood tolerant, native to the project
area, and fast growing. A total of 2,500 stems per acre will be planted in these areas. Dense
planting has proven effective in competing with RCG (Celedonia 2002).
• The installation of planting hummocks at a density of two per acre within RCG removal
areas will provide microtopography and locations to establish trees. The hummocks will
have approximately a ten -foot diameter. Hummocks will be underlain with a weed -barrier
layer (preferably cardboard or other biodegradable material), covered by 18 to 24 inches of
imported weed -free compost -amended soil, and planted with two native coniferous trees, two
native deciduous trees, and six native shrubs. Establishing trees in the RCG removal areas
should discourage RCG in the long-term.
Post -Planting RCG Management
Post -planting management will consist of spot -spraying any new RCG growth in the treatment
areas and replacing dead woody plantings as needed to achieve performance standards for woody
cover (see Chapter 3). Spot -spraying and replanting activities will be a direct result of adaptive -
management recommendations generated from quarterly and annual site visits conducted by
WSDOT. Control will be triggered when it appears that RCG is preventing woody plant
establishment or dominating large portions of the site. In the long-term, deciduous and
coniferous woody plantings will limit light penetration to the understory, greatly reducing the
potential for future RCG colonization.
Establishing Woody Vegetation
Establishing woody vegetation is critical to improving wetland functions. Woody vegetation
provides shade, surface roughness, habitat structure, nutrient uptake, organic matter production,
and a source for woody debris. Its establishment will be facilitated in the following ways:
• Reducing competition. In treatment areas, RCG control will be accomplished as described
above, allowing a window of opportunity for woody plants to establish in these areas.
• Creating variable topography. Planting hummocks will create varied growing conditions
for plant establishment. Creating slightly drier areas will increase the likelihood that tree
plantings will have proper growing conditions in these areas and reduce RCG
re-establishment.
• Densely planting competitive native woody vegetation. Dense planting has proven
effective in competing with RCG (Celedonia 2002). Plantings will primarily consist of
deciduous woody species that are flood tolerant, native to the project area, and fast growing.
• Replacing dead plants. Failed plantings will be replaced with species from the planting
plan if performance standards are not being met or monitoring results indicate that replanting
may be necessary to meet future standards. Replacement plantings may be relocated or
substituted with other species from the planting plan to improve success.
• Monitoring for and minimizing RCG establishment. RCG will be controlled so that
woody vegetation performance standards can be met. Direct controls, both mechanical
and/or chemical, will be used to reduce RCG competition with new plantings and to limit
expansion of RCG colonies.
Chapter 2 May 2006
Establishment of the Bank Page 2-7
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
2.5.4 Strategy to Manage Himalayan Blackberry
Himalayan blackberry is not listed as a noxious weed in Washington, but this invasive non-
native species poses an ecological threat. It readily invades riparian areas, forest edges,
meadows, roadsides, and relatively open areas, including all open forest types. Once it becomes
well established, Himalayan blackberry out -competes understory native vegetation and prevents
native plant communities from establishing. It is currently present in many of the uplands and
riparian areas in the various units and as an understory species in Units C and E.
The strategy for managing Himalayan blackberry involves an initial mechanical and chemical
treatment, monitoring, and ongoing management.
• Initial Treatment. During site construction, all areas of Himalayan blackberry will be
treated. In large monotypic stands, treatment will involve mowing the aboveground
vegetation and applying herbicide. In areas where blackberry is mixed with native
vegetation, treatment will involve targeted spot -spraying or cut -and -treat methods of
control.
• Monitoring. During the operational life of Springbrook Bank, both formal and informal
assessments of Himalayan blackberry cover will be conducted. The effects of the
blackberry identified during these site visits will be assessed and management actions
recommended.
• Ongoing Management. During the operational life of Springbrook Bank, Himalayan
blackberry will be controlled as often as necessary to ensure that the performance standards
are met.
2.5.5 Strategy to Manage other Invasive Non -Native Vegetation
Other invasive non-native vegetation occurring at Springbrook Bank will be managed according
to King County Noxious Weed Law (King County 2005) and the Washington State Noxious
Weed List (Washington State Noxious Weed Control Board 2005). Additional measures will be
taken to control the establishment of Japanese knotweed, purple loosestrife, and English ivy at
the site.
• Initial Treatment. All Japanese knotweed, purple loosestrife, and/or English ivy identified
at the site prior to or during construction will be removed using methods appropriate to the
species found. Any Class A or Class B noxious weeds designated for control in King
County that are identified onsite will also be removed.
• Monitoring. During the operational life of Springbrook Bank, yearly site visits will be
conducted to identify any of the target species. If identified, locations will be documented
and/or flagged and appropriate staff notified to schedule weed control activities.
• Ongoing Management. If and when any of the targeted species are found, they will be
managed during the same calendar year using control and removal methods appropriate for
the particular species. Early season control to prevent seed -set and removal of seed heads
may also be implemented to prevent future establishment.
Chapter 2 May 2006
Establishment of the Bank Page 2-8
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
2.6 MITIGATION BANK PLAN
Mitigation treatments for each unit are described below and in Table 2-2. All elevations
referenced in this chapter are in the North American Vertical Datum 1998 (NAVD88). Elements
of the mitigation bank plan are also shown on the following figures:
Mitigation Types - (Figures 2-1 to 2-5);
Mitigation Treatment Activities - (Figures 2-6 to 2-9);
Grading Plans - (Figures 2-10 to 2-13); and
Planting Plans - (Figures 2-14 to 2-17).
Table 2-2. Mitigation Treatment Type and Acreage Summary by Unit
Mitigation Treatment Type
Acreage
Unit A
Unit B
Unit C
Unit D
Unit E
Total
Wetland Re -Establishment
0.05
0.12
9.27
-
8.35
17.79
Wetland Rehabilitation
19.93
31.17
1.06
--
-
52.16
Wetland Enhancement - Type 1
--
--
4.69
--
-
4.69
Wetland Enhancement - Type II
-
--
-
2.63
-
2.63
Forested Wetland Enhancement
--
--
23.23
2.00
--
25.23
Riparian Upland Enhancement
0.64
1.48
-
-
4.44
6.55
Upland Habitat Enhancement
--
--
7.80
--
--
7.80
Protection Setback (Buffer)
2.65
3.43
1.64
-
1.98
9.70
Trail Zone
2.66
--
--
--
-
2.66
Totals
25.93
36.20
47.69
4.63
14.77
129.22
2.6.1 Units A and B (62.47 acres)
2.6.1.1 Wetland Rehabilitation Area (5].1Oacres)
Wetland rehabilitation is the dominant mitigation treatment within Units A and B. The creation
of hydrologic connections through the existing berms in Unit A and B will reconnect
Springbrook Creek to floodplain wetlands and their functions at stream elevations greater than
the 12-foot contour. Areas dominated by reed canarygrass will be treated and replaced with
native woody vegetation. Habitat structures and planting hummocks for tree establishment will
also be installed.
When the water surface elevation of Springbrook Creek rises above the 12-foot contour, the
berm breaches will allow for water to enter Units A and B more frequently and at lower flows
than the two-year storm event. This will occur roughly five days (114 hours) annually, and one
day (23 hours) during the growing season (based on modeling of full build -out watershed
conditions). Floodwaters from Springbrook Creek will disperse across Units A and B, which are
relatively flat, and extend inundation and/or saturation during the growing season. Occasional
over -bank flooding from Springbrook Creek is not expected to adversely affect existing
vegetation classes or types in Units A and B. For detailed hydrologic analysis, see Springbrook
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Wetland and Habitat Mitigation Bank: Springbrook Creek Hydrological Analysis (WSDOT
2005b).
2.6.1.1 a Construction Elements — Site preparation within 15.6 acres dominated by reed
canarygrass, including the riparian area next to Springbrook Creek, will involve mowing and
herbicide treatment. The wetland re-establishment areas in the berm breaches will be cleared
and grubbed, graded, and planted (see section 2.6.1.2 for more details on breaches). Three
habitat structures per acre (vertical snags, brush piles, and/or LWD) will be placed in reed
canarygrass treatment areas and the cattail area in Unit B. Two planting hummocks per acre will
be installed in the areas where reed canarygrass is removed. Figure 2-6 shows all treatment
activities for Unit A and B.
2.6.1. lb Planting — A total of 2,500 native trees and shrubs per acre will be installed within
planting areas. Woody species appropriate for the various hydroperiods will be planted as
containerized and/or bare -root stock including: Oregon ash, red -osier dogwood, Sitka and Pacific
willows, and peafruit wild rose (Wetland Tree/Shrub #2). Containerized Sitka spruce, western
red cedar, Oregon Ash, black cottonwood, and Pacific ninebark will be planted on the
constructed hummocks (Hummock Plantings).
2.6.1.1 c Functional Gain — Springbrook Creek is one of the few remaining tributary streams in
the Lower Green River Basin. In a landscape that is nearly completely developed enhancing and
protecting the last remaining natural areas is a high priority. This protection will sustain the
viability of remaining fish and wildlife populations. The location of Units A and B along the
habitat corridor of Springbrook Creek greatly increases their value within the surrounding
landscape and complements existing restoration projects both up and downstream.
Re-establishing the hydrologic connection between Springbrook Creek and Units A and B will
restore the floodplain wetlands to fully functioning riverine Hydrogeomorphic class wetlands
(see Section 1.4.4 Wetlands) while increasing floodplain function. Establishing additional
woody vegetation and creating microtopography with planting hummocks will increase surface
roughness, slow water velocities during flood events, and may increase residence time of
floodwater at the site. The connectivity will also improve the creek's access to available flood
storage and potentially reduce peak flow elevations and duration during high -flow events, which
would provide downstream benefits. The increased interaction between Springbrook Creek and
Units A and B should improve the removal of sediments, nutrients, and toxicants from the creek
during flood events. The increase in vegetation classes over portions of Units A and B will
provide additional capacity to uptake nutrients and toxicant, which will potentially improve
water quality in the creek. Breaching the berm, adding planting hummocks, installing
approximately three habitat structures per acre (vertical snags, brush piles, and/or logs), and
establishing trees on planting hummocks will increase habitat complexity and result in more
diverse habitat niches (Table 2-3).
Units A and B are located adjacent to a lower reach of Springbrook Creek. This proximity to the
creek and the increased connectivity provided by the berm breaches will allow the improvements
to water quality, hydrologic, floodplain, and riparian functions provided in these units to benefit
downstream aquatic habitat in Springbrook Creek, the Green River, and Duwamish River and its
estuary. Allowing areas of cattail (Typha latifolia) to remain in portions of Unit B will allow for
greater habitat diversity and may encourage habitat utilization by great blue heron from the
nesting colony located in the nearby Black River Riparian Forest. The cattail area will maintain
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
a third vegetation class (emergent) and habitat interspersion in Unit B. Cattails also provide high
quality feeding, breeding, and nesting habitat for red -winged blackbirds and marsh wrens.
Cattail seeds are an important food source for waterfowl, and the rhizomes and leaves provide
food and shelter for muskrats. Cattails are very efficient at removing excess nutrients and
toxicants from aquatic systems due to their high annual productivity and tolerance of inundation.
Preserving the cattails will allow their contribution to water quality improvement in Springbrook
Creek to continue. Adding a minimum of thirteen pieces of LWD, snags, and/or brush piles in
the cattail area will provide additional habitat niches where they are currently lacking.
Placement of a minimum of five snags will allow for increased raptor use by increasing the
number of locations available for perching, foraging, and nest building. These snags may also
encourage woodpecker foraging for invertebrates and potential nesting in the future. The
addition of brush piles and LAID will increase the number and diversity of refuge and foraging
locations for amphibians, invertebrates, and small mammals.
2.6.1.2 Wetland Re -Establishment Area (0.17 acre)
The 0.17-acre Wetland Re -Establishment Area is located where seven sections of the berm next
to Springbrook Creek will be removed. A fisheries biologist reviewed the design for Units A
and B to evaluate the effects on fish related to breaching the berms. This evaluation concluded
that the proposed site alteration from breaching the berms would restore natural floodplain
habitat beneficial to fish and likely reduce fish stranding (WSDOT 2006). Springbrook Bank
will result in net improvements to fish habitat.
2.6.1.2a Construction — Three 20-foot long by 2- to 3-foot-deep breaches will be excavated in
the berm in Unit A, and four in Unit B. Soils will be amended with incorporated compost to
improve soil fertility and organic matter content. Disturbed soils will be protected from erosion
with coir or jute fabric.
2.6.1.2b Planting — Native trees and shrubs will be installed at a density of 2,500 stems per acre
including: Oregon ash, red -osier dogwood, Sitka and Pacific willows, and peafruit wild rose
(Wetland Tree/Shrub #2).
2.6 L I c Functional Gain — Increasing wetland area and allowing Springbrook Creek increased
access to the floodplain will provide substantial increases in wetland function. Replacing
existing reed canarygrass with dense native woody vegetation will increase canopy closure over
time. Woody plantings will increase the number of vegetation strata in portions of the site,
eventually increase vertical stratification over time, and increase the number of native species
present onsite (Table 2-3).
2.6.1.3 Riparian Upland Enhancement Area (2.12 acres)
The 2.14-acre riparian upland enhancement area includes the unexcavated area of the berm and
embankment next to Springbrook Creek. Existing reed canarygrass will be replaced with native
woody vegetation, which will improve riparian habitat and shade the stream channel.
2.6.1.3a Construction — Reed canarygrass will be mowed and treated with herbicide.
2.6.1.3b Planting — Scouler's willow, big -leaf maple, red alder, Sitka spruce, Douglas -fir, and
snowberry will be planted at a density of 1,500 stems per acre (Riparian Upland Plantings).
2.6.1.1 c Functional Gain — Increased shade, provided by riparian tree and shrub plantings, will
reduce water temperatures and increase dissolved oxygen in Springbrook Creek, improving fish
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
and wildlife habitat. Leaf litter from deciduous trees and shrubs will increase organic matter
export to the stream providing aquatic food -chain support (Table 2-3).
Z 6.1.3 Protection Setback Area (6.08 acres)
A 6.12-acre 40-foot-wide protection setback area will be created around the outer perimeter of
Units A and B to protect the wetland from disturbance related to adjacent roads and
developments (Oakesdale Avenue SW, SW 27th Street, and Lind Avenue SW). The protection
setback includes both existing wetlands and uplands. Native woody plantings will be established
in areas where woody cover is lacking or invasive non-native vegetation is removed.
2.6.1.3a Construction — Himalayan blackberry and other invasive non-native vegetation present
within the buffer will be selectively removed prior to planting native woody species.
2.6.1.3b Plantings — Protection setback plantings in uplands will include Douglas fir, big -leaf
maple, serviceberry, oceanspray, beaked hazel and snowberry (Upland Plantings) at 1,500 stems
per acre. Protection setback plantings in wetlands will include Oregon ash, red -osier dogwood,
Sitka and Pacific willows, and peafruit wild rose (Wetland Tree/Shrub #2) at 2,500 stems per
acre.
2.6.1.3c Functional Gain — Planting dense woody vegetation in the buffer areas will protect
habitat functions over the larger site from disturbance related to surrounding land use. Units A
and B will primarily provide habitat for small mammals, aquatic mammals, invertebrates, and
birds.
2.6.1.4 Trail Zone (2.66 acres)
A 2.66-acre non -credit -generating Trail Zone will be established around the boardwalk running
north -south in Unit A to serve as a buffer between the trail and portions of Unit A (see Figure 2-
2). All mitigation treatment activities within the trail zone will be applied accordingly. This
includes reed canarygrass removal and native woody plantings.
The Trail Zone includes the 8-foot-wide trail footprint and a 40-foot-wide protection setback
area on both sides of the proposed trail. This will create an approximately 88-foot-wide by
1,365-foot long area that will not generate mitigation credits. By removing the 88-foot-wide
Trail Zone (2.66 acres) from Springbrook Bank, approximately 0.90 credit will not be generated.
Wetland rehabilitation will be performed within the Trail Zone as proposed throughout Unit A.
In order to construct the trail, existing vegetation within an 18-foot-wide temporary construction
corridor will be cleared, the 8-foot-wide trail will be constructed, and all areas not occupied by
the trail will be planted with woody vegetation. Areas dominated by reed canarygrass will be
mowed and treated with herbicide as part of the wetland rehabilitation treatment in Unit A.
The trail will provide a significant environmental education opportunity in an urban area under
intense development pressure. The trail design and construction will utilize all available best
management practices (BMPs) to minimize disturbance to adjacent habitat within Unit A.
Within the Trail Zone, a net increase of 1.17 acres of woody vegetation will result after trail
construction and re -vegetation work. This increase of woody vegetation is nearly 100%
compared to existing conditions. The completed Trail Zone will offset the impacts to woody
vegetation and wetlands from trail construction, and provide a substantial increase in wetland
function and vegetative structure. It is expected that the efforts to minimize impacts and enhance
vegetation within the non -credit -generating Trail Zone will mitigate the impacts from
constructing the trail.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Construction of the trail has been carefully designed to minimize environmental impacts. The
design team has considered the potential environmental impacts of the trail to Unit A and has
incorporated appropriate design features to minimize these impacts as follows.
Alignment Change: The City owns an easement along Springbrook Creek for the trail
connection. To improve and protect riparian habitat and functions, the City is revising the trail
footprint further away from the stream than originally planned for in the easement. This
alignment will minimize impacts to established shrubs and trees by aligning the trail to the
greatest extent practicable through existing patches of reed canarygrass. The trail will run
roughly parallel with the creek on the west side of Unit A.
Elevated Boardwalk: The trail will be built as a boardwalk, elevated an average of 3 feet above
the existing ground surface, except at the ends where it will connect to the existing trail system.
The elevation will minimize impacts to the wetland, allow some vegetation to grow under the
trail, and maintain connectivity of wildlife and hydrology. WDFW has indicated that they do not
expect deer to be present in the area, and site visits by project biologists have noted the lack of
any existing game trails on the site. Without the presence of deer onsite, the 3-foot vertical
clearance should be adequate to allow passage of other wildlife species that may be present.
Elevating the trail will minimize flooding of the trail from Springbrook Creek to the greatest
degree possible and minimize impacts to sensitive wetland areas.
Narrower Trail: By narrowing the trail footprint to 8 feet, the construction impacts and
footprint will be minimized. The typical width for City of Renton trails is 12 feet. Benches will
be located in two designated areas with interpretive signage at one of the two locations. At these
locations the trail may be widened 5 additional feet to 13 feet in width for sections up to 15 feet
in length.
Handrails: Handrails will be installed along both sides of the entire boardwalk and be designed
to prevent pedestrians from leaving the designated trail.
Materials: A pre -cast concrete diamond -pier pin foundation system will be used. This low -
impact foundation system eliminates the need for pouring concrete footings and consequently
will greatly reduce the extent of impacts to wetlands. Also, plastic wood will be used to
construct the posts and beams, which will be exposed to occasional flooding. Plastic wood, cedar
timber, or other nontoxic materials will be used to construct the decking and railings.
Pet Control: Plastic -coated fencing will be incorporated as part of the handrail design along the
boardwalk to prevent pet access into the wetland area. Pet stations will also be installed at the
northern and southern trail ends to collect pet waste.
Dense Veeetation: Dense vegetation will be established and/or existing vegetation will be
supplemented adjacent to the trail to deter people from entering the wetland from the trail.
Limited Access: Bollards at each end of the trail will deter bicycle and other unauthorized
vehicular access.
Instructive Sianage: Signs posted at each end of the trail will identify the trail for pedestrian
use only and include a posting of the City's adopted Park Rules and Regulations. All users must
remain on the trail. Dogs must be on a leash (Council -adopted Park Rules and Regulations).
Additional signage directing bicyclists to the appropriate alternate routes will also be placed at
both ends of the trail and at logical points prior to the restricted use section of the trail.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Educational Sianne: Benches will be placed at two locations along the trail to facilitate
passive recreation, such as bird watching. In addition, interpretive signs at the designated seating
areas will describe the unique natural features and environmental benefits of the Springbrook
Creek wetlands.
Minimized Construction Impacts: Clearing the minimum amount of desirable vegetation
necessary to construct the trail using an 18-foot-wide temporary construction corridor, narrowing
the trail footprint, and implementing all available BMPs will minimize construction impacts.
Undesirable vegetation immediately adjacent to the trail will be removed and disposed of
appropriately. Disturbed areas will be re -vegetated with native plant materials.
2.6.2 Unit C (47.69 acres)
2.6.2.1 Wetland Re -Establishment Area (9.27 acres)
The 9.27-acre Wetland Re -Establishment Area is the second largest treatment area in Unit C.
Excavation of up to 7 feet of existing fill will place the lowest finish grade at the 16-foot
elevation. The bottom of the created wetland will interface with seasonal groundwater. In order
to ensure positive drainage and provide the potential for groundwater interaction, the 16-foot
elevation was chosen to mesh with existing topography of the site, match up with the bottom of
the existing conveyance ditch from which water is being diverted onto the Wetland
Re -Establishment Area, and match the existing grade below the downstream outlet structure.
Additional treated surface and ground water (average of 45,000 cubic feet of water per month)
will also be redirected from the South 180th Street grade separation project to the north end of
Unit D via a new pipe, then via the conveyance ditch through BNSF property to the south of
Unit C and into the Wetland Re -Establishment Area (currently the water from this project is
routed to Springbrook Creek). The conveyance ditch will be plugged near its entrance to Unit C
and flows will be directed into this area. Wetland hydrology will be established below the 17-
foot elevation. An adjustable -height weir will be installed at the outflow point in the northeast
corner of the Wetland Re -Establishment Area to ensure saturation and up to 2 inches of seasonal
inundation at the 16.2-foot elevation. This supplemental water will extend the hydrology up to
five weeks in the late spring and three weeks in the late summer. For detailed hydrologic
analysis, see Springbrook Wetland and Habitat Mitigation Bank: Unit C Water Balance
Memorandum (WSDOT 2005c).
Analysts examined soils from geotechnical borings at the proposed excavation depth. The soils
range from sandy gravel and sand to silty sand (fill), to interbedded sand and silt underneath the
areas of fill, and poorly graded sand to silt at the bottom of the soil borings. Peat was also
discovered intermixed in many of the soil layers (Hart Crowser 2005a).
2.6.2.1 a Construction — Approximately 100,000 cubic yards of fill will be excavated and
removed from historic wetlands with heavy equipment. This area will be fully cleared and
grubbed prior to grading. The lowest finish grade in this area will be at the 15-foot contour, in a
small area directly in front of the adjustable -height weir in the northeast corner of the excavated
area. The entire Wetland Re -Establishment Area will be rough -graded to allow for
microtopographic variation. After grading, a minimum of 3 inches of compost will be
incorporated to a depth of 12 inches within the excavated area. The existing conveyance ditch
will be plugged at several locations below the diversion point. Three habitat structures per acre
(vertical snags, brush piles, and/or LWD) will be placed throughout the re-establishment area.
(Figure 2-7 shows all treatment activities for Unit C.)
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
2.6.2.1 b Planting — This area will be planted with native trees and shrubs at 2,500 stems per acre.
The wetter bottom area (below the 16-foot contour) will be planted with Oregon ash, red -osier
dogwood, Sitka and Pacific willows, and peafruit wild rose (Wetland Tree/Shrub #2). Fringe
wetland areas (between the 16-foot and 20-foot contours) will be planted with Pacific ninebark,
black twinberry, Oregon ash, black cottonwood, Sitka willow, and Nootka rose (Wetland
Tree/Shrub #1). Disturbed soils will be mulched with a minimum of 3 inches of woody mulch to
deter reed canarygrass and other weed establishment and control erosion.
2.6.2.1 c Functional Gain — Removal of fill material in the wetland re-establishment area will
increase storage capacity for water delivered to the site from the existing conveyance ditch
running from Unit D to the south edge of Unit C. Planting dense woody vegetation will increase
surface roughness and decrease water velocities, which will reduce potential erosion and delay
surface water flows from leaving the site. The Wetland Re -Establishment Area will provide soil
saturation for extended periods, allowing the uptake of dissolved nutrients and toxicants from
solution. Increasing the number of vegetation classes throughout Unit C will allow greater
uptake of nutrients and toxicants. Re-establishment of additional wetland area will also increase
wetland functions (Table 2-4) and increase available wetland habitat for wetland -dependent and
wetland associated birds, mammals, and invertebrates.
2.6.2.2 Wetland Rehabilitation Area (1.06 acres)
A 1.19-acre wetland rehabilitation area is associated with portions of the existing conveyance
ditch and new drainage path. This area is dominated by existing native trees and shrubs, which
will be protected. Native coniferous trees will be under -planted in these areas.
2.6.2.2a Construction — All areas of invasive non-native vegetation will be selectively removed
to protect existing woody vegetation. Three habitat structures per acre (vertical snags, brush
piles, and/or LWD) will be placed throughout the wetland rehabilitation area.
2.6.2.2b Planting — Conifer under -plantings will include Sitka spruce, western hemlock, and
western red cedar (Wetland Forest Under -Plantings) at a density of 100 stems per acre.
2.6.2.2c Functional Gain — Coniferous woody vegetation will increase the quantity and quality
of habitat niches. Woody plantings will increase canopy closure, the number of vegetation
strata, and provide additional buffering from adjacent land uses. Under -planted conifers will
increase native species richness and habitat structural diversity (Table 2-4).
2.6.2.3 Forested Wetland Enhancement Area (23.23 acres)
The 23.32 acres of wetland enhancement is the largest treatment area in Unit C. Areas
dominated by existing native trees and shrubs will be under -planted with native conifers.
2.6.2.3a Construction — Areas of existing Himalayan blackberry will be selectively removed.
2.6.2.3b Planting — Sitka spruce, western hemlock, and western red cedar (Wetland Forest
Under -Plantings) will be planted in existing forested wetland areas at a density of 100 trees per
acre.
2.6.2.3c Functional Gain — Native conifer plantings will increase species diversity, the number
of vegetation strata, and the structural complexity of these areas (Table 2-4).
2.6.2.4 Wetland Enhancement Type I (4.69 acres)
Existing reed canarygrass will be removed and native woody plants established.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
2.6.2.4a Construction — Site preparation within areas dominated by reed canarygrass will include
mowing and herbicide treatment. Three habitat structures per acre (vertical snags, brush piles,
and/or LAID) will be placed throughout the Wetland Enhancement Area.
2.6.2.4b Planting — Nootka rose, red -osier dogwood, Sitka spruce, black cottonwood, red alder,
Scouler's willow, and western red cedar (Wetland Tree/Shrub #3) will be installed at 2,500 stems
per acre.
2.6.2.4c Functional Gain — Establishing woody vegetation in reed canarygrass removal areas
will provide an increase in vegetation classes, which will provide additional uptake of nutrients
and toxicants, and increase habitat structure. Installing habitat structures (snags, brush piles,
and/or LWD) and establishing conifers will increase habitat niches, species diversity, and
structural diversity (Table 2-4).
2.6.2. S Upland Habitat Enhancement Area (7.80 acres)
The 7.80-acre upland habitat enhancement area will be located in the northern and western
portions of Unit C. Enhancement of these areas will consist of replacing invasive non-native
vegetation with native trees and shrubs.
2.6.2.5a Construction — Areas of existing Himalayan blackberry will be removed. Mowing and
herbicide treatment will be used to remove reed canarygrass. Three habitat structures per acre
(vertical snags, brush piles, and/or LWD) will be placed throughout the upland habitat
enhancement area.
2.6.2.5b Planting — Douglas fir, big -leaf maple, serviceberry, oceanspray, beaked hazel, and
snowberry (Upland Plantings) will be planted at 1,500 stems per acre in upland areas.
2.6.2.5c Functional Gain — Woody vegetation and habitat structures (vertical snags, brush piles,
and/or LWD) will provide vertical habitat stratification that further increases the quantity and
quality of habitat niches. Woody plantings will increase canopy closure, the number of
vegetation strata, and provide additional buffering from adjacent land uses.
2. 6.2. 6 Protection Setback Area (L 64 acres)
A 1.63-acre non -credit -generating 40-foot-wide buffer will be created to protect the wetland
from Oakesdale Avenue SW and development to the south. The buffer includes existing
wetlands and uplands. Native woody plantings will replace invasive non-native vegetation.
2.6.2.6a Construction — Invasive non-native vegetation will be selectively removed within the
40-foot-wide buffer area along Oakesdale Avenue SW.
2.6.2.6b Planting — Plantings in upland areas will include Douglas fir, big -leaf maple,
serviceberry, oceanspray, beaked hazel, and snowberry (Upland Plantings) planted at 1,500
stems per acre. Plantings in wetland areas will include Oregon ash, red -osier dogwood, Sitka
and Pacific willows, and peafruit wild rose (Wetland Tree/Shrub #2) planted at 2,500 stems per
acre.
2.6.2.6c Functional Gain — Woody plantings will increase canopy closure, the number of
vegetation strata, and provide additional buffering from adjacent land uses. The addition of
native woody species will also provide increased habitat functions within the protection setback
areas.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
2.6.3 Unit D (4.71acres)
2.6.3.1 Wetland Enhancement Type II Area (2.63 acres)
A 2.63-acre Wetland Enhancement Type II Area is located at the north end of Unit D.
Hydrology in this area will be augmented with an average of approximately 45,000 cubic feet of
water per month, which will be conveyed from a stormwater treatment pond directly south of the
unit, via a new pipe, to the inundated area at the north end of Unit D. The stormwater treatment
pond is a combined detention and water quality treatment facility designed to detain and treat
surface runoff and groundwater from the Tukwila South 180th Street Grade Separation Project.
The pond was sized for water quality treatment in accordance with the requirements of 1998
King County Surface Water Design Manual (King County 1998). Surface runoff that collects in
the roadway, and groundwater seepage that collects under the concrete roadway slab, is collected
and drained to a wet well. The water is then pumped to a gravity system before discharging to
the detention/water quality pond. The pond discharges to a pipe system that currently discharges
to Springbrook Creek to the east of the pond. The new diversion pipe from the treatment pond
will be buried in an existing roadbed. This will provide additional water to the Unit C Wetland
Re -Establishment Area and extend the hydroperiod in the northern portion of Unit D.
A permanent easement was granted to the City of Tukwila by the City of Renton allowing all
stormwater facilities to be owned and maintained by the City of Tukwila. The City of Renton is
the original owner of the property, and has the authority to require the City of Tukwila to
maintain the stormwater facilities in a working condition at all times and in perpetuity.
2.6.3. ]a Construction — Installation of a new diversion structure and conveyance pipe from the
pump station treatment/detention pond to inundated area at north end of the unit. (Figure 2-8
shows all treatment activities for Unit D.)
2.6.3.1 b Planting — No plantings are planned for this area.
2.6.3.1 c Functional Gain — Providing additional water to this area will create additional
hydrologic regimes (water depth classes and durations of inundation) and/or extend the period of
inundation in this area providing an increase in habitat niches (Table 2-5).
2.6.3.2 Forested Wetland Enhancement Area (2..00 acres)
A 2.08-acre Forested Wetland Enhancement Area is located in the south portion of Unit D.
Invasive non-native vegetation will be removed from the understory of the existing forested
wetlands. All other existing native trees and shrubs will be undisturbed. Native conifer trees
will be under -planted in existing forested wetlands. The 0.25-acre area disturbed in constructing
the storm sewer will be planted with native trees and shrubs.
2.6.3.2a Construction — Clearing, grubbing, and grading will be limited to approximately a
0.25-acre wetland area needed to construct the new pipe that will convey supplemental water to
the Wetland Enhancement Type II Area. Brush piles will be placed within the disturbed area.
2.6.2.4b Planting — Sitka spruce, western hemlock, and western red cedar (Wetland Forest
Under -plantings, Table 2-1) will be used for under -planting in the forested wetlands, at a density
of 100 trees per acre. The area disturbed in constructing the storm sewer pipe will be planted
with 2,500 stems per acre of Oregon ash, red -osier dogwood, Sitka and Pacific willows, and
peafruit wild rose (Wetland Tree/Shrub #2). Three inches of woody mulch will be placed in this
area.
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2.6.2.4c Functional Gain — Under -planting will increase habitat complexity in wetland
enhancement areas by improving vegetation strata and native plant diversity. Woody vegetation
and habitat structures, such as brush piles, will increase the quantity and quality of habitat niches
(Table 2-5).
2.6.4 Unit E (14.75acres)
2.6.4.1 Wetland Re -Establishment Area (8.35 acres)
The 8.37-acre Wetland Re -Establishment Area includes creating riverine flow -through wetland
conditions at Unit E by removing existing fill materials and connecting these wetlands to the
creek. The low -flow channels will be the lowest elevation in the unit at the 9-foot contour (just
above summer base -flow of Springbrook Creek), which will be inundated for the majority of the
year. The low -flow channels have been designed to direct floodwater from the wetland back into
Springbrook Creek as it recedes. These channels will prevent any isolated pools of standing
water from forming and prevent fish stranding. Three sections of the existing berm will be
removed to connect Unit E to Springbrook Creek. Elevations below the 11.5-foot contour will
be saturated at least ten percent and inundated approximately one percent of the growing season
(March 1 — October 31). Wetlands are not expected to re-establish at elevations above the 11.5-
foot contour. The majority of the Wetland Re -Establishment Area's final grade, between the 9-
foot and 11.5-foot elevations, will be located in a low -permeability silt layer. These elevations
were selected based on the number of hours of inundation and saturation in the growing season
estimated using a continuous time series model of Springbrook Creek combined with
geotechnical information on soil conditions at the proposed elevations and regional groundwater
inputs during the early growing season (WSDOT 2005b, Hart Crowser 2005a). The remainder
of the Wetland Re -Establishment Area will be seasonally inundated. This area will be planted
with native trees and shrubs.
Analysts examined soils taken from geotechnical borings of soils to be exposed through
excavation. The soils range from sandy gravel and sand to silty sand (fill) on top, to interbedded
sand and silt underneath the fill, then soft to medium stiff dark gray silt to sandy silt (low -
permeability layer) and poorly graded sand to silt at the bottom of the soil borings. Peat was also
intermixed and discovered in many of the soil layers (Hart Crowser 2005a).
Surface water inundation and inputs of groundwater from the more permeable sand/silty sand
layers above and below the low -permeability layer will be important to the hydrology of the
Wetland Re -Establishment Area. Surface water flooding will provide periodic inundation
relatively frequently during the early growing season. The upper sand/silty sand layer will
provide water to the site via seepage from the excavated slopes after infiltration from rainfall and
flood events. A portion of the seepage will re -infiltrate into the bottom terrace of the excavated
area and help maintain saturated conditions. The lower sand/silty-sand layer will provide a
steady source of water via "leakage" into the silt layer from below, as the aquifer in this layer
appears to be under pressure during the winter and through the early growing season. These
sources of hydrology will maintain saturation in the Wetland Re -Establishment Area during time
periods that surface water inundation is not present. For a more detailed surface water hydrology
analysis, see Springbrook Wetland and Habitat Mitigation Bank: Springbrook Creek
Hydrological Analysis (WSDOT 2005b).
2.6.4. ]a Construction — Approximately 149,716 cubic yards of existing fill will be excavated in
Unit E. The Wetland Re -Establishment Area will be fully cleared and grubbed prior to grading.
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Three habitat structures per acre (vertical snags, brush piles, and/or logs) will be placed
throughout this area. The lowest elevations will be rough -graded to allow for microtopographic
and water regime variation. A minimum of 3 inches of compost will be incorporated to a depth
of 12 inches in excavated areas. All disturbed soils will be covered with a minimum of 3 inches
of woody mulch to deter reed canarygrass growth and promote woody plant establishment.
Disturbed areas adjacent to the creek will be protected with coir or jute fabric and/or quarry
spalls to prevent erosion. Construction in Unit E will likely be phased over two construction
seasons to minimize impacts to fish in Springbrook Creek. The majority of the site behind the
berm will be excavated and planted in the first season. In the second construction season any
remaining areas will be planted after the berm is breached, allowing the creek access to off -
channel habitat in Unit E. (Figure 2-9 shows all treatment activities for Unit E.)
2.6.4.1 b Planting — The wetter bottom area (below the 10-foot contour) will be planted with
Oregon ash, red -osier dogwood, Sitka and Pacific willows, and peafruit wild rose (Wetland
Tree/Shrub #2). Fringe wetland areas (between the 10- and 12-foot contours) will be planted
with Pacific ninebark, black twinberry, Oregon ash, black cottonwood, Sitka willow, and Nootka
rose (Wetland Tree/Shrub #1). Areas above the 12-foot contour will be planted with red -osier
dogwood, Sitka spruce, black cottonwood, Nootka rose, Scouler's willow, and western red cedar
(Wetland Tree/Shrub #3). Woody plants will be installed as live stakes, bare -root, and/or
containerized stock at a density of 2,500 woody stems per acre.
2.6.4.1 c Functional Gain — Re-establishing the hydrologic connection between Springbrook
Creek and Unit E will increase functions and. processes of the wetland floodplain. The
re-established wetland hydrology will provide soil saturation for extended periods, allowing the
uptake of dissolved nutrients and toxicants. Increasing the area available for treatment by
increasing the ratio of the wetland to stream width will increase the likelihood of water quality
improvement. Establishing woody vegetation and creating microtopography will increase
surface roughness, slow water velocities during flood events, and increase residence time of
floodwater at the site. Off -channel habitat created at Unit E will provide important refuge and
rearing habitat for fish in Springbrook Creek, and improve a limiting factor for salmon recovery
in the Springbrook Creek Sub -Basin (Kerwin and Nelson 2000) (Table 2-6).
Unit E is located adjacent to one of the lower reaches of Springbrook Creek. This proximity to
the creek will allow the improvements to water quality, hydrologic, floodplain, and riparian
functions provided in Unit E to benefit downstream aquatic habitat in Springbrook Creek, the
Green River, and Duwamish River and its estuary. Springbrook Creek is one of the few
remaining tributary streams to the Green River. In a highly urbanized landscape, enhancing and
protecting the last remaining natural areas is a high priority and will sustain the viability of
remaining fish and wildlife populations. The location of Unit E along the habitat corridor of
Springbrook Creek greatly increases its value within the surrounding landscape and
complements existing restoration projects both up and downstream.
Z 6.4.2 Riparian Upland Enhancement Area (4.42 acres)
The 4.42-acre Riparian Upland Enhancement Area includes the remaining sections (islands and
peninsulas) of the berm next to Springbrook Creek and upland areas surrounding the Wetland
Re -Establishment Area. A portion of the existing cottonwood stand will be protected and under -
planted with native trees and shrubs. Native woody plantings will be established in areas where
woody cover is lacking.
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2.6.4.2a Construction — Areas of existing Himalayan blackberry and other invasive non-native
vegetation will be selectively removed. Three habitat structures per acre (vertical snags and/or
LWD) will be placed in portions of the riparian enhancement area.
2.6.4.2b Planting — Scouler's willow, big -leaf maple, red alder, Sitka spruce, Douglas -fir, and
snowberry (Riparian Upland Plantings) will be installed in areas lacking woody vegetation in the
riparian enhancement area at 1,500 plants per acre. Under -plantings in existing deciduous forest
will include Sitka spruce, western hemlock, and western red cedar (Wetland Forest Under -
Plantings). A total of 100 plants per acre will be installed in those areas.
2.6.4.2c Functional Gain — Increased shade provided by riparian plantings may decrease water
temperatures and increase dissolved oxygen in Springbrook Creek, which would benefit water
quality and fish. Increased organic matter in the form of leaf litter would increase organic matter
export to the creek, which provides food -chain support. Establishing dense woody vegetation
will increase canopy closure, the number of vegetation strata, and vegetative species diversity
(Table 2-6).
2.6.4.3 Protection Setback Area (1.98 acres)
A 2.11-acre non -credit -generating 40-foot-wide buffer will be created to protect the wetlands in
Unit E from Oakesdale Avenue SW and development to the north. The buffer will include
existing uplands. Native woody plantings will be established to increase plant diversity, habitat
structural diversity, and cover of woody plants. Existing native trees will not be removed. These
areas will be under -planted with native conifer species.
2.6.4.4a Construction — All non-native invasive vegetation will be selectively removed within
areas dominated by reed canarygrass. Existing Himalayan blackberry within the 40-foot buffer
area along Oakesdale Avenue SW and the northern edge of the property will be selectively
removed.
2.6.4.4b Planting — Native woody plantings will be installed at a density of 1,500 stems per acre.
Species to be planted include Douglas fir, big -leaf maple, serviceberry, oceanspray, beaked
hazel, and snowberry (Upland Plantings).
2.6.4.4c Functional Gain — Establishing dense woody vegetation will increase canopy closure,
the number of vegetation strata, and provide buffering from surrounding land uses.
2.7 FUNCTIONAL IMPROVEMENT
Substantial functional improvements are expected from Springbrook Bank at various scales:
watershed, mitigation bank unit, and treatment type. Functional gains for each treatment type
were summarized in the previous sections. Functional gains at the watershed scale and at the
mitigation bank scale are described in the following sections.
2.7.1 Watershed Scale
Substantial functional improvements are expected at the watershed level as a result of
establishing Springbrook Bank. The proximity of Springbrook Bank to the lower reaches of
Springbrook Creek will allow the improvements to water quality, hydrologic, floodplain, and
riparian functions provided in these units to benefit downstream aquatic habitat in Springbrook
Creek, the Green River, and Duwamish River and its estuary. Springbrook Creek is one of the
few remaining tributary streams to the Green River. The habitat value of associated natural areas
may be difficult to replicate due to landscape position, water supply availability, urbanization of
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
the surrounding area, and historic hydrologic manipulation of natural hydrologic systems in the
Lower Green River Basin. Protecting and enhancing these sites will help to sustain the viability
of remaining fish and wildlife populations such as Chinook salmon and the great -blue heron -
nesting colony located in the Black River Riparian Forest. Improvements at Springbrook Bank
will address limiting factors for the Springbrook Creek sub -basin including: degraded riparian
condition, poor water quality, and lack of off -channel habitat in the watershed (Kerwin and
Nelson 2000; WRIA 9 Steering Committee 2005).
2.7.2 Mitigation Bank Unit Scale
Significant increases to wetland, stream, riparian, and floodplain functions will result at
Springbrook Bank by: re-establishing, rehabilitating, and enhancing wetlands; enhancing upland
habitat; and improving riparian conditions along Springbrook Creek. Water quality, hydrologic,
and habitat functions are expected to increase significantly at Springbrook Bank. Tables 2-3
through 2-6 summarize the expected functional improvements for each unit, and list the
attributes that contribute to wetland function in existing and future conditions. The site attributes
examined were taken from Method for Assessing Wetland Functions (Hruby et al. 1999) and the
Wetland Rating System for Western Washington (Hruby 2004). These methods include
comprehensive lists of attributes that contribute to wetland function. Existing and proposed
conditions are rated qualitatively using three categories (Poor, Moderate, and High).
Work performed at Springbrook Bank will increase the variety of hydrologic regimes, number
and structure of vegetation communities, number and diversity of physical structures, and
wetland size. Therefore, improvements will result for many attributes used in Hruby et al.
(1999) and Hruby (2004).
• Units A and B — Twelve of the eighteen functional attributes listed in Table 2-3 will be
positively affected; three of three water quality attributes, two of four hydrologic attributes,
and seven of eleven habitat attributes will be positively affected.
• Unit C — Ten of the eighteen functional attributes listed in Table 24 will be positively
affected in addition to a substantial increase in wetland area; two of four water quality
attributes, one of three hydrologic attributes, and seven of eleven habitat attributes will be
positively affected.
• Unit D — Three of the eighteen functional attributes listed in Table 2-5 will be positively
affected; two of four water quality attributes and one of eleven habitat attributes will be
positively affected.
• Unit E — Seventeen of the eighteen functional attributes listed in Table 2-6 will be
positively affected, in addition to a substantial increase in wetland area and fish rearing and
refuge habitat; three of three water quality attributes, three of four hydrologic attributes, and
eleven of eleven habitat attributes will be positively affected.
2.8 CONSTRUCTION MONITORING
WSDOT will monitor site construction to ensure work is completed according to site plan sheets
and permit conditions. Site elevations will be surveyed routinely during excavation in Units A,
B, C, and E during construction to confirm elevations. As -Built drawings will be generated post -
construction. Photo -documentation of site construction will be kept on file. Woody habitat
structures and plant material will be inspected, properly stored, and installed.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Bank performance standards, included in Chapter 3, will measure site success. Performance
standards will address as -built condition, grading accuracy, planting success and cover, and
installation/retention of woody habitat structures. Monitoring reports will specifically address
each aspect of site construction.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Table 2-3. Existing and Proposed Function Attributes for Suingbrook Bank, Units A and B (Riverine)
WATER UALITY IMPROVEMENT FUNCTION ATTRIBUTES
Function Attribute
Existing Condition
Mitigation Work
Proposed Condition
Vegetation classes
Moderate — 2 to 3 vegetation classes
Mow, apply herbicide, create
Moderate to High — Replace large reed
present (Unit A: forested, scrub-
microtopography, and plant trees
canarygrass emergent wetlands with forested
shrub, emergent; Unit B: forested,
and shrubs in large areas
and scrub -shrub vegetation classes.
emergent).
dominated by reed canarygrass,
Establishing tree and shrub classes in the
including riparian areas.
riparian areas contribute to improving water
quality in Springbrook Creek.
Understory vegetation
Low— Limited understory
Plant native trees and shrubs.
Moderate — Area and complexity of
development
understory vegetation will increase.
Width ratio of wetland to
Low — Wetland is 30 to 70 times the
Breach 20-foot berm sections
High — Reconnecting the wetland floodplain
stream
stream width, but wetlands are
next to Springbrook Creek—
to Springbrook Creek substantially increases
hydrologically disconnected from
3 breaches in Unit A;
the effective width ratio of wetland to stream.
Springbrook Creek.
4 breaches in Unit B.
HYDROLOGIC FUNCTIONS ATTRIBUTES
Storage capacity
Moderate — Wetland has potential to
Breach berm sections next to
High — Breaching berm sections increases
store large volumes of stormwater.
Springbrook Creek.
available storage capacity for floodwaters
Low opportunity to store floodwater
from Springbrook Creek.
from creek because berms restrict
connection.
Size ratio of wetland to
Low — Wetlands represents a small
Breach berm sections next to
Low — The effective floodplain area will be
basin
portion of total basin area.
Springbrook Creek.
increased, but that increase is relatively small
compared to the basin drainage area.
Ratio of wetland to stream
High — Stream extends total length of
Breach berm sections next to
High — No change in ratio, but connectivity
wetland, but connectivity is low.
Sp rin brook Creek.
will be substantially increased.
Cover by woody vegetation
Moderate — Woody vegetation
Plant native trees and shrubs.
High — Overall cover by woody vegetation
covers approximately 33 percent of
will increase in wetlands currently dominated
Unit A and 60 percent of Unit B.
by reed canarygrass, including riparian areas.
HABITAT FUNCTIONS ATTRIBUTES
Buffer condition
Low — Buffers are relatively narrow
Within a 40-foot buffer screen
Moderate — Weed removal and native woody
and disturbed.
around the perimeter of Units A
plantings will improve buffer condition.
and B, remove weeds and plant
with native trees and shrubs.
Plant native trees and shrubs in
riparian enhancement area.
Canopy closure over
Varies from Low to Moderate —
Mow, apply herbicide, create
High — Overall canopy closure by woody
wetlands
Woody vegetation covers
microtopography, and plant
vegetation will increase in reed canarygrass
approximately 33 percent of Unit A
native trees and shrubs in large
removal areas.
and 60 percent of Unit B.
areas currently dominated by
reed canarygrass.
Canopy closure over stream
Low —Very little woody vegetation
Mow, apply herbicide, and jute
High — Canopy closure over stream will
present along stream
matting, plant trees and shrubs
increase replacing reed canarygrass.
along riparian corridor currently
dominated by reed canarygrass.
Number of vegetation strata
Moderate — 3 strata present (tree,
Mow, apply herbicide, create
Moderate — Tree and shrub strata will replace
shrub, herb).
micro -topography, and plant
the herb layer in large areas dominated by
native trees and shrubs in large
reed canarygrass.
areas currently dominated by
reed canarygrass.
Number of snags
Low — Few or no snags.
Install vertical snags in treatment
High — Number of snags will substantially
areas.
increase.
Number of LWD
Low — Little or no LWD.
Install large woody debris and
High — Number of LWD and brush piles will
brush piles in treatment areas.
substantially increase.
Vegetation interspersion
Moderate — Most of the areas have a
Install native trees and shrubs
Moderate — Increase vegetation interspersion
moderate degree of interspersion.
and create micro -topography in
with structurally complex boundaries by re -
large areas dominated by reed
habilitating forested and scrub -shrub
canarygrass.
wetlands, and enhancing riparian uplands.
Number of hydrologic
Moderate — 3 hydrologic regimes
Install planting hummocks to
Moderate — No change to number of
regimes
(seasonally saturated, occasionally
create microtopography in reed
hydrologic regimes, but the wetland area with
inundated, seasonally inundated).
canarygrass removal areas.
the various hydrologic regimes will be
increased.
Number of water depth
Moderate — 2 depth classes (0-8", 8-
Install planting hummocks to
Moderate — No change to number of depth
classes
40").
create microtopography in reed
classes, though complexity will increase by
canarygrass removal areas.
creating micro -topography.
Species richness
Low — Between 4 to 8 species
Plant up to 5 additional species
Moderate — Native species richness will
present, depending on area. No
in reed canarygrass removal
increase as a result of plantings.
conifers are present.
areas.
Mature woody vegetation
Moderate — Areas of mature woody
Retain existing mature woody
High — Plantings will provide more mature
vegetation are present.
vegetation. Plant native trees and
woody vegetation as the site becomes
shrubs in large areas dominated
established.
by reed canarygrass.
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Table 2-4. Existing and Proaosed Function Attributes for Springbrook Bank, Unit C (Deiwessional)
WATER UALITY IMPROVEMENT FUNCTION ATTRIBUTES
Function Attribute
Existing Condition
Mitigation Work
Proposed Condition
Vegetation classes
Moderate — 3 vegetation classes
Create forest/scrub-shrub in
Moderate — Same number of vegetation
present (deciduous forest, scrub-
wetland re-establishment area;
classes, but improved composition (deciduous
shrub, emergent).
Create forest/scrub-shrub
forest, mixed forest, scrub -shrub). Reed
wetlands in reed canarygrass
canarygrass-dominated emergent wetlands
removal areas; Create mixed
will be replaced by forest/scrub-shrub.
forest by under -planting
Under -planting conifers will create mixed
coniferous trees in deciduous
forest. Area of forest/scrub-shrub will be
forest.
enlarged in wetland re-establishment area.
Understory vegetation
Low to Moderate — Limited
Plant native conifers in the
Moderate — Diversity and complexity of
understory development. Forested
understory of existing deciduous
understory vegetation will increase.
areas have shrub understory that is
forest.
largely Himalayan blackberry.
Storage capacity
Moderate — Wetland has capacity to
Excavate fill to re-establish
Moderate — Newly created wetlands will
store additional water.
forest/scrub-shrub wetlands.
increase storage capacity.
Area seasonally inundated
Low — Only small portion of
Excavate historic fill expanding
Moderate — Additional wetlands onsite will
wetlands onsite have seasonal
wetland area onsite and
provide substantial new area of seasonal
inundation
providing additional areas with
inundation.
seasonal inundation.
HYDROLOGIC FUNCTIONS ATTRIBUTES
Storage capacity
Moderate — Wetland has capacity to
Excavate fill to re-establish
Moderate — Newly created wetlands will
store additional water.
forest/scrub-shrub wetlands.
increase storage capacity.
Size ratio of wetland to
Moderate to High — Wetland
Excavate fill to re-establish
Moderate to Hieh — The wetland area will be
basin
represents approximately 15 percent
forest/scrub-shrub wetlands.
increased, but that increase is relatively small
of sub -basin drainage area.
compared to the sub -basin drainage area.
Cover by woody vegetation
Varies from Low to High — Woody
Plant native trees and shrubs
High — Overall cover by woody vegetation
vegetation covers approximately 83
will increase.
percent of the wetlands in Unit C.
HABITAT FUNCTIONS ATTRIBUTES
Buffer condition
Moderate —Buffers are greater than
Plant native trees and shrubs
Moderate — Plantings will improve buffer
100 meters for 50% of wetland.
within a 40-foot buffer screen
condition.
along Oakesdale Ave. SW and
portion of BNSF property to the
south.
Canopy closure
Varies from Low to High — Woody
Plant native trees and shrubs.
High — Overall canopy closure by woody
vegetation covers approximately 83
vegetation will increase.
percent of the wetlands in Unit C.
Number of vegetation strata
Moderate — Three strata present
Plant native trees and shrubs.
Moderate — Tree and shrub strata will
(tree, shrub, herb).
Under -plant native coniferous
develop within the wetland re-establishment
trees in deciduous forest.
and reed canarygrass removal areas. Conifers
under -planted in deciduous forest will
contribute to near -term development of the
sub -canopy stratum.
Number of snags
Varies from Low to Moderate —
Install vertical snags in re-
High — Number of snags will substantially
Few or no snags in Wetlands C-2/C-
establishment and RCG removal
increase.
3; up to 4 classes of snags in Wetland
areas.
C-1.
Number of LWD
Varies from Low to Moderate —
Install large woody debris and
High — Number of LWD and brush piles will
Little or no LWD in Wetlands C-2/C-
brush piles in re-establishment
substantially increase.
3, up to 4 classes of snags present in
and RCG removal areas.
Wetland C-1.
Vegetation interspersion
Low to Moderate — Most areas have
Excavate fill and plant
High — Increase vegetation interspersion with
low to moderate degree of
forest/scrub-shrub in wetland re-
structurally complex boundaries by re -
interspersion
establishment area;
establishing, rehabilitating, and enhancing
Establish forest/scrub-shrub
forested and scrub -shrub wetlands.
wetlands in reed canarygrass
removal areas; Create mixed
forest by under -planting conifers
in deciduous forest.
Number of hydrologic
Moderate — 3 hydrologic regimes
Re-establish new wetland area.
Moderate — No change to number of
regimes
(seasonally saturated, occasionally
Excavate micro -topography in
hydrologic regimes, but the wetland area with
inundated, seasonally inundated).
the wetland re-establishment and
the various hydrologic regimes will be
install planting hummocks in
increased.
reed canarygrass removal areas.
Number of water depth
Moderate — 2 depth classes (0-8", 8-
Re-establish new wetland area.
Moderate — No change to number of water
classes
40").
Excavate micro -topography in
depth classes, but the wetland area with the
the wetland re-establishment
depth classes will be increased.
area.
Species richness
Moderate — From 6 to 8 species
Plant up to 10 additional native
High — Native species richness will increase
present, depending on area. No
wetland tree and shrub species.
as a result of plantings.
conifers are present.
Area seasonally inundated
Low — Only small portion of
Excavate historic fill expanding
Moderate — Additional wetlands onsite will
wetlands onsite have seasonal
wetland area onsite and
provide substantial new area of seasonal
inundation
providing additional areas with
inundation.
seasonal inundation.
Mature woody vegetation
Moderate — Areas of mature woody
Retain existing mature woody
High — Plantings will provide more mature
vegetation are present.
vegetation. Plant native trees and
woody vegetation as the site becomes
shrubs throughout.
I established.
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Table 2-5. Existing and Prouosed Function Attributes for Springbrook Bank, Unit D (Detwessional)
WATER QUALITY IMPROVEMENT FUNCTION ATTRIBUTES
Function Attribute
Existing Condition
Mitigation Work
Proposed Condition
Vegetation classes
Moderate — 3 vegetation classes
Create mixed forest by under-
Moderate to High — Increased number of
present (deciduous forest, scrub-
planting coniferous trees in
vegetation classes and improved composition
shrub, emergent).
deciduous forest.
(deciduous forest, mixed forest, scrub -shrub,
emergent). Under -planting conifers will create
mixed forest.
Understory vegetation
Low — Limited unclerstory
Plant native conifers in the
Moderate — Diversity and complexity of
development
understory of existing deciduous
understory vegetation will increase.
forest.
Storage capacity
Moderate — Wetlands that exist
No action planned to increase
Moderate — No change anticipated.
onsite store water.
Lstorage capacity.
Area seasonally inundated
Moderate — Wetlands onsite have
Add additional water from 43`
Moderate — Additional water may increase
seasonal inundation
St grade separation project.
seasonal inundation
HYDROLOGIC FUNCTIONS ATTRIBUTES
Storage capacity
Moderate — Wetland has capacity to
No action planned.
Moderate — No change.
store stormwater.
Size ratio of wetland to
Moderate — Wetland represents
No action planned.
Moderate — No change.
basin
approximately 5 percent of the sub -
basin drainage area
Cover by woody vegetation
Moderate — Woody vegetation
Under -plant native coniferous
Moderate — No change to percentage of
covers approximately 60 percent of
trees in deciduous forest.
woody vegetation, but composition will
the wetland in Unit D.
improve.
HABITAT FUNCTIONS ATTRIBUTES
Buffer condition
Low — Buffers are narrow and
No action planned.
Low — No change.
disturbed.
Canopy closure
Moderate — Woody vegetation
Under -plant native coniferous
Moderate — No change in canopy closure, but
covers approximately 60 percent of
trees in deciduous forest.
composition will improve.
the wetland in Unit D.
Number of vegetation strata
Moderate — 3 strata present (tree,
Under -plant native coniferous
Moderate — Conifers under -planted in
shrub, herb).
trees in deciduous forest.
deciduous forest will contribute to near -term
development of the sub -canopy stratum.
Number of snags
Low — Few snags in Unit D.
No action planned.
Low — No change.
Number of LWD
Low — Little LWD in Unit D.
Install brush piles in the wetland
Moderate — Brush piles will increase the
enhancement area.
amount of downed wood.
Vegetation interspersion
Low — Unit D has low degree of
No action planned.
Low — No change.
interspersion.
Number of hydrologic
Moderate — 3 hydrologic regimes
Supplement hydrology with
Moderate — Hydroperiod may be extended.
regimes
(seasonally saturated, occasionally
surface water from 1801h Street
inundated, seasonally inundated).
grade separation project.
Number of water depth
Moderate — 2 depth classes (0-8", 8-
Supplement hydrology with
Moderate — No increase to the number of
classes
40").
surface water from 180`h Street
depth classes, but the hydroperiod may be
grade separation project.
extended.
Species richness
High — 15 species present in Unit D.
Plant 3 native coniferous tree
High — Native species richness will improve
No conifers are present.
species to increase native plant
as a result of plantings.
diversity.
Area seasonally inundated
Moderate — Wetlands onsite have
Add additional water from 180th
Moderate — Additional water may increase
seasonal inundation
Street grade separation project.
seasonal inundation.
Mature woody vegetation
Moderate — Areas of mature woody
Retain existing mature woody
Moderate — Conifer plantings will provide
vegetation are present.
vegetation. Under -plant native
mature woody vegetation over time.
coniferous trees in deciduous
forest.
Chapter 2
Establishment of the Bac
CH 21107_030106.doc
May 2006
Page 2-25
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Table 2-6. Existin! and Proposed Function Attributes for Sprin2hrook Bank. Unit E (Riverine)
WATER QUALITY IMPROVEMENT FUNCTION ATTRIBUTES
Function Attribute
Existing Condition
Mitigation Work
Proposed Condition
Vegetation classes
Low — No wetlands are present in
Excavate fill and plant native
Moderate — The re-established wetlands will
Unit E. The riparian uplands include
trees and shrubs in wetland re-
include two vegetation classes (deciduous
three vegetation classes (deciduous
establishment area;
forest and scrub -shrub). Under -planting
forest, scrub -shrub, emergent).
Plant native trees and shrubs in
conifers will create mixed upland forest.
riparian enhancement area;
Create mixed forest by under -
planting coniferous trees in
u land deciduous forest.
Understory vegetation
Low — Limited understory
Plant native trees and shrubs,
Moderate — Diversity and complexity of
development.
including conifers in the
understory vegetation will increase.
understory of existing upland
deciduous forest.
Width ratio of wetland to
Low — No wetlands are present in
Excavate fill and plant native
High — The re-established floodplain wetland
stream
Unit E.
trees and shrubs in wetland re-
area will be approximately 45 meters wide
establishment area.
and connected to S rip brook Creek.
HYDROLOGIC FUNCTIONS ATTRIBUTES
Storage capacity
Low — No wetlands are present in
Excavate fill to re-establish new
High — Re-established wetlands will increase
Unit E.
wetland and connect to
storage capacity onsite.
S rip brook Creek.
Size ratio of wetland to
Low — No wetlands are present in
Excavate fill to re-establish new
Low — 8 acres of wetlands will be re -
basin
Unit E.
wetland and connect to
established. This represents a small portion of
S rip brook Creek.
total basin area.
Ratio of wetland to stream
Low — No wetlands are present in
Excavate fill to re-establish new
High — Re-established wetland will extend the
Unit E.
wetland and connect to
length of stream within Unit E.
S rip brook Creek.
Cover by woody vegetation
Low — Uplands in Unit E have
Plant native trees and shrubs.
High — Overall cover by woody vegetation
approximately 40 percent cover of
will increase.
woody vegetation.
HABITAT FUNCTIONS ATTRIBUTES
Buffer condition
Moderate — The riparian buffer is
Plant 40-foot buffer screen along
Moderate — Plantings will improve buffer
more than 50 meters wide and is
Oakesdale Ave. SW and
condition.
disturbed by off -road vehicles.
northern edge with native trees
and shrubs. Plant native trees
and shrubs in riparian
enhancement area.
Canopy closure over
Low — Uplands in Unit E have
Plant native trees and shrubs.
Moderate — Overall canopy closure by woody
wetlands
approximately 40 percent cover of
vegetation will increase.
woody vegetation.
Canopy closure over stream
Moderate — The majority of the
Plant additional native trees and
High — Gaps in canopy closure over the
stream has mature woody vegetation.
shrubs in riparian areas.
stream be planted with trees and shrubs
increasing canopy closure.
N amber of vegetation strata
Low — No wetlands are present in
Plant native trees and shrubs.
High — Tree and shrub strata will develop
Unit E.
within the wetland re-establishment area.
Conifers under -planted in upland deciduous
forest will contribute to near -term
development of the sub -canopy stratum.
Number of snags
Low — No snags in Unit E.
Install vertical snags in re-
High — Number of snags will substantially
establishment areas.
increase.
Number of LWD
Low — No LWD in Unit E.
Install large woody debris and
High — Number of LWD and brush piles will
brush piles in re-establishment
substantially increase.
and portions of the riparian area.
Vegetation interspersion
Low — Unit E has a low degree of
Excavate fill and plant native
High — Increase vegetation interspersion with
vegetation interspersion.
trees and shrubs in wetland re-
structurally complex boundaries by re-
establishment area;
establishing forested and scrub -shrub
Plant native trees and shrubs in
wetlands, and enhancing riparian uplands.
riparian enhancement area;
Create mixed forest by under -
planting coniferous trees in
upland deciduous forest.
Number of Hydrologic
Low — No wetland hydrology is
Excavate fill to re-establish new
High — Wetlands will be re-established with 4
regimes
present in Unit E.
wetland area. Excavate micro-
hydrologic regimes (intermittently flooded,
topography in the wetland re-
temporarily flooded, seasonally flooded, and
establishment area.
semi -permanently flooded).
Number of water depth
Low — No inundation areas are
Excavate fill to re-establish new
High — Wetlands will be re-established with 2
classes
present in Unit E.
wetland area. Excavate micro-
water depth classes (0-8", 840").
topography in the wetland re-
establishment area.
Sl-)ecies richness
Low — No wetlands are present in
Plant 10 wetland native tree and
High - Native species richness will
Unit E.
shrub species, and 11 upland
substantially increase as result of plantings.
native tree and shrubspecies.
Mature woody vegetation
Moderate — Mature woody
Retain existing mature woody
High — Plantings will provide more mature
vegetation present over small area.
vegetation. Plant native trees and
woody vegetation as the site becomes
shrubs throughout.
established.
CH 211A7_030106.doc
Chapter 2 May 2006
Establishment of the Bank Page 2-26
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LEGEND
WETLAND RE-ESTABLISHMENT
F-1 WETLAND REHABILITATION
RIPARIAN UPLAND ENHANCEMENT
FORESTED
WETLAND ENHANCEMENT
WETLAND ENHANCEMENT TYPE I
WETLAND ENHANCEMENT TYPE II
UPLAND HABITAT ENHANCEMENT
BUFFER FROM TRAIL
BUFFER FROM PARCEL BOUNDARY
— —— CITY LIMITS
PARCEL BOUNDARY
RAILROAD TRACK
EXISTING CONVEYANCE DITCH
PROPOSED DRAINAGE PATH
PROPOSED STORM SEWER
• — - — EXISTING TRAIL
- - - - PROPOSED TRAIL
• BENCHES
Mitigation Types
Overview
Figure 2-1
Springbrook Creek Wetland and Habitot Mitigation Bank
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Springbrook Creek Wetland and Habitat Mitigo
Springbrook Creek Wetland and Habitat Mitigation Bank
Soringbrook Creek Wetland and Habitat Mitigation Bar
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SCALE IN FEET
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Figure 2-5
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REMOVAL. HYDROLOGIC
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VERTICAL SNAG
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SCALE IN FEET
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a e Figure 2-7
Sorinobrook Creek Wetlono and Habitat Mitioation Bank
3
4
EXISTING
STORMWATER
POND
EXISTING WETLAND
MITIGATION
1 TUKWILAI
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I : F-1
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L .�. P.G. ^ -- r-1 HYDROLOGIC ALTERATION
RAILROAD TRACK
EXISTING CONVEYANCE DITCH
CITY LIMITS
P.R. — EXISTING TRAIL
BRUSH PILE
13AKESDALE BUSINESS
PARK
S.
DRAINS TO
UNIT C
0 60 120
SCALE IN FEET
Unit D Mitigation
Treatment Activities
Figure 2-8
Springbr OOk Creek Wetland and Habitat '4 " 1
OHWM
ESTIMATED 0HW4
UNIT E LEGEND
F-1
INVASIVE REMOVAL ANO UPLAND PLANTING
FGRADING HYDROLOGICAL
ALTERATiON, AND
WETLAND PLANTING
INVASIVE REMOVAL AND
F-1 CONIFER UN DERPL AN T I NG
PROPOSED DRAINAGE PATH
ExISTING TRAIL
VERTICAL SNAG
LOG
0 so 110
SCALE IN FEET
Unit E Mitigation
Treatment Activities
Figure 2-9
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ORDINARY HIGH WAI&;::,PAgw/
4 PROPOSED CONTOURS
EXISTING CONTOURS 0 80 160 Units A and 13 rau ing Plan
EXISTING WETLAND BOUNDARY SCALE IN FEET Figure 2-10
I
Springbrook Creek Wetland and Habitat Wtigot7on Bank
UNIT C
0 00
if
0 80 160 4 SCALE N
SCALE IN FEET
Cur
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CUT CUT
-FILL- FILL
PROPOSED CONTOURS
EXISTING CONTOURS
EXISTING WETLAND BOUNDARY
• MONITORING WELL
Units C Grading Plan
Figure 2-11
Springbrook Creek Wetland and Habitat Mitigation Bonk
p
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0 BO 160
SCALE IN FEET
LEGEND
—CUT— CUT
—FILL— FILL
+� PROPOSED CONTOURS
�#p« EXISTING CONTOURS
^— - -- - -^ EXISTING WETLAND BOUNDARY
B. M. S. F.
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Figure 2-12
Springbrook Creek Wetland and Habitat Mitigation Bank
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-[UT CUT 4y',
EXISTING R.R. SPUR
-TILL- GILL
PROPOSED DRAINAGE PATH
+� PROPOSED CONTOURS
EXISTING CONTOURS
Unit E Grading Plan
Figure 2-13
Springbrook Creek Wetland and Habitat Mitigation Bank
Master Plant Materials List
(same as Table 2.1)
Wetland Tree/Shrub #1 wetter
Riparian Upland Plantings
Oregon ash Fraxinus latifolia
Big -leaf maple Acer macro h llum
Black twinber Lonicera involucrata
Red alder Alnus rubra
Pacific ninebark Ph socar us ca itatus
Sitka spruce Picea sitchensis
Black cottonwood Po ulus balsamifera
Douglas -fir Pseudotsu a menziesfi
Nootka rose Rosa nutkana
Scouler's willow Salix scouleriana
Sitka willow Sa/ix sitchensis
Snowber S mphorica os a/bus
Wetland Tree/Shrub #2 wettest
Upland Plantings
Red -osier dogwood Corpus sericea
Big -leaf maple Acer macro h llum
Oregon ash Fraxinus latifolia
Serviceber Ame/anchier a/nifolia
Peafruit wild rose Rosa isocar a
Beaked hazel (Corylus cornuta
Pacific willow Salix lucida
Oceanspray Holodiscus discolor
Sitka willow Salix sitchensis
Douglas -fir Pseudotsu a menziesii
Snowber S m horicar os a/bus
Wetland Tree/Shrub #3 wet
Hummock Plantings
Red -osier dogwood Corpus sericea
Oregon ash Fraxinus latifolia
Sitka spruce Picea sitchensis
Pacific ninebark Ph socar us ca itatus
Black cottonwood Po ulus balsamifera
Sitka spruce Picea sitchensis
Nootka rose Rosa nutkana
Black cottonwood Po ulus balsamifera
Scouler's willow Salix scouleriana
Western red cedar Thu'a licata
Western red cedar Thu'a licata
Wetland Forest Under -Plantings
Sitka spruce Picea sitchensis
Western red cedar Thu'a licata
Western hemlock Tsu a hetero h lla
ME
■M1
■MI
0 80 160
SCALE 1N FEET
I i
ti y
A
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UNIT D
-----------._
t
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A
DAKESDALE BUSINESS LEGEND
PARK
® WETLAND TREE/ SHRUB •2
® WETLAND FOREST UNDER -PLANTING
BRUSH PILE
w^ - •--� - -- EXISTING WETLAND BOUNDARY
Unit D Planting Plan
Figure 2-16
Springbrook Creek Wetland and Habitat Mitigation Bank
ON
UNIT E
I!
11=1 I 1=11 i-1 11Eld
110 160 III ill _ —1 I I—III-111
SCALE IN FEET / r
III—i I I— l lI— =1 I I —III —III I illyl I I 1-1—
l .�
—III—I 1 II I I —I I I —I I I —I I I —I =1 i
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C7 r
j
�.4 ; j LEGEND
r.
IW � ED
vE it Axp TREE/ 5HRu8 •i
p VERTICAL SNAG
•3 �'� YETLAND TREE/ SHRUB •2
YETLAND TREE/ SHRUB •J
EXISTING R.R. SPAR s.l ® RIPARIAN UPLAND PLANTING
® YETLAND FOREST UNDER -PLANTING
® UPLAND PLANTING
Unit E Planting Plan
Figure 2-17
Springbrook Creek Wetland and Habitat Mitigation Bank
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
3.0 PROJECT GOAL, OBJECTIVES, AND PERFORMANCE
STANDARDS
3.1 GOAL
The goal of the Springbrook Bank is to increase wetland area, improve hydrologic, water quality,
and habitat functions, increase fish refuge/rearing habitat, and promote environmental education.
3.2 ECOLOGICAL OBJECTIVES
1. Increase wetland area at Springbrook Bank by removing fill material in Units A, B,
C, and E to re-establish wetland functions on 17.79 acres.
2. Improve hydrologic functions by increasing wetland area and flood storage capacity
in Units A, B, C, and E; extending wetland hydroperiod in Units A, B, C, and D;
increasing the connectivity of wetlands in Units A, B, and E to Springbrook Creek;
and increasing cover of woody vegetation in portions of all units.
3. Improve water quality functions by increasing wetland acreage; adding additional
vegetation classes; increasing the connectivity of wetlands in Units A, B, and E to
Springbrook Creek; and increasing the ratio of wetland to stream width in Unit E.
4. Improve habitat functions by increasing canopy closure; the number of vegetation
strata; the number of water depth classes; the number of vertical snags, brush piles,
and large woody debris (LWD); canopy closure over the wetlands and stream; the
number of hydrologic regimes; the number of native plant species; the number of
plant assemblages; vegetation class interspersion; improve buffer condition; increase
the diversity of plant communities in areas currently dominated by reed canarygrass
and Himalayan blackberry; and improving off -channel fish refuge and rearing habitat
in Unit E.
5. Improve floodplain and riparian function by re-establishing hydrologic connectivity
to Springbrook Creek and increasing woody cover directly adjacent to the creek in
Units A, B, and E.
3.3 PERFORMANCE STANDARDS
The performance standards described below provide benchmarks for measuring achievement of
the goal and objectives of the Springbrook Bank. Mitigation activities are intended to meet these
performance standards within a specified time frame. The performance standards are based on
function attributes described in Method for Assessing Wetland Functions (Hruby et al. 1999).
These function -based performance standards correlate design, monitoring, and demonstrated
improvements in site conditions. Methods to monitor each performance standard are described
in general terms. A detailed monitoring plan is included in Appendix A. The performance
standards, monitoring methods, related objectives, functions, and function attributes are
summarized in Tables 3-1 through 3-4.
Grading/Hydrologic Performance Standards
The grading/hydrologic performance standards help to document and verify that wetland area
and ground elevations are established according to the criteria specified during the design. These
performance standards directly relate to Ecological Objectives 1, 2, 3, and 4. The related
MBI Ch3_Perf Stds_050106.da
Chapter 3 May 2006
Project Goal, Objectives, and Performance Standards Page 3-1
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
functions are water quality, hydrologic, and habitat. Delineating the Wetland Re -Establishment
areas at Springbrook Bank will demonstrate that wetland area has increased. After construction,
ground elevations will be surveyed and documented on As -Built drawings, demonstrating that
site grading has achieved the design elevations necessary to establish wetland conditions and
provide intended functions.
Delineating wetland area will demonstrate an increase in the related attributes: wetland area,
wetland width relative to Springbrook Creek, and wetland size relative to the basin. Increasing
wetland area relative to Springbrook Creek and its basin provides a larger area for floodwaters to
be stored and treated by vegetation and soils. Documenting hydrology in the early growing
season within the Wetland Re -Establishment areas will document that the hydrologic conditions
required to establish wetlands in these areas is being provided.
Documenting accurate ground elevations in As -Built drawings for Units C and E demonstrates
an increase in the related attributes of flood storage capacity and the number of hydrologic
regimes. Lowering ground elevations increases storage capacity and creating microtopography
slows floodwaters, which reduces erosion and encourages sediment deposition. Creating
multiple hydrologic regimes establishes habitat niches that can be used by wildlife. The creation
of off -channel fish refuge and rearing habitat in Unit E will benefit fish populations present in
Springbrook Creek. Monitoring hydrology in the Wetland Re -Establishment areas will
demonstrate that these areas have adequate hydrology for wetland development. Monitoring
hydrology in Units A and B will demonstrate the improved connectivity between Springbrook
Creek and the adjacent wetlands and the change in HGM class from depressional to riverine of
the wetlands behind the existing berms.
Vegetation Performance Standards
The woody vegetation performance standards directly relate to Ecological Objectives 2, 3, 4 and
5. The related functions are water quality, hydrologic, habitat, and riparian/floodplain.
Measuring woody vegetation will demonstrate the increase in the related attributes: vegetation
classes; cover by woody vegetation; canopy closure; and number of vegetation strata. Woody
vegetation provides surface roughness to slow floodwaters, which reduces erosion and
encourages sediment deposition. Establishing canopy closure and increasing the number of
vegetation strata will provide habitat structure and increase uptake of nutrients introduced to the
site by Springbrook Creek. Establishing woody vegetation in the riparian areas in Units A, B,
and E will replace a reed canarygrass monoculture and increase shading of the active stream
channel. Converting reed canarygrass areas in Units A and B to native woody plant communities
will increase species and structural diversity in areas currently dominated by non-native invasive
plant species. Ensuring that a diverse plant community develops in re-established wetlands and
areas currently dominated by invasive species will demonstrate the increased habitat value at the
sites. Reducing the cover of Himalayan blackberry and actively managing high priority invasive
species will allow native plant communities to become established providing habitat for other
native species.
Woody Habitat Structures Performance Standards
The woody habitat structures performance standards verify that habitat structures have been
installed at Springbrook Bank. These performance standards are associated with Ecological
Objective 4. Vertical snags, brush piles, and LWD provide habitat by creating niches for
MBI Ch3_Perf Stds_WD6.doc
Chapter 3 May 2006
Project Goal, Objectives, and Performance Standards Page 3-2
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
wildlife. Measuring habitat structures will demonstrate an increase in the related attributes:
vertical snags, brush piles, and LWD.
3.4 REMEDIAL ACTION
The remedial action requirements listed below will apply to all performance standards listed in
Tables 3-1 through 3-4. It will apply in the case that the original performance standard is not
met in a timely fashion, and either additional work is required, a reduction in credits connected to
the standard is warranted, or a replacement performance standard is approved by the Corps and
Ecology, following consultation with the other BOC members.
WSDOT, in consultation with the City, will propose management activities to correct any issues
encountered during the establishment phase of the Bank. If the monitoring reports or inspection
by representatives of the BOC agencies indicate persistent failure to achieve and maintain the
prescribed performance standards, WSDOT will propose adaptive management actions to correct
the shortcomings. The BOC agencies may also unilaterally direct adaptive management actions,
following consultation with WSDOT and the City, if the BOC agencies identify a need for
corrective action and no adaptive management plan acceptable to the BOC has been submitted
within a reasonable period of time. Alternatively, following consultation with the City and
WSDOT, the Corps and Ecology, in consultation with the other BOC members, may decline to
direct or authorize any action to correct any grading, wetland area, woody vegetation, or woody
habitat structures, and may instead delay, reduce, or deny credit under any of the performance
standards listed above for Units A, B, C, D, or E. Any adaptive management plan will specify the
nature of further examination of areas for potential causes of failure and/or corrective activities
to be conducted, the schedule of completion for those activities, and a monitoring plan for
assessing the effectiveness of the corrective action. The objective of the adaptive management
plan will be to attain the originally prescribed performance standards, unless the BOC expressly
establishes replacement performance standards, following consultation with the City and
WSDOT, in light of circumstances and conditions observed at the site. The Sponsors will also
implement all appropriate mitigation that the BOC determines is necessary to compensate for
those authorized impacts to the aquatic environment that have not been successfully redressed by
the Bank pursuant to the requirements of this Agreement. If WSDOT propose to institute
replacement performance standards, WSDOT may not initiate activities designed to achieve
those replacement standards until those performance standards are approved by the Corps and
Ecology following consultation with the other BOC members. During the period that a specific
performance standard of the Bank is out of compliance, the BOC may direct that credits
generated by that Bank performance standard may not be sold, used, or otherwise transferred.
If remedial actions taken by WSDOT under the provisions of the preceding paragraph do not
bring that performance standard of the Bank into compliance with the requirements of this
Agreement, including any approved changes to the Agreement, WSDOT may provide written
notice of their intent to discontinue efforts to achieve one or more performance standards of the
Bank. Upon providing such notice, no additional credits may be established for that performance
standard, but at the discretion of the BOC, the Sponsor may be released from future maintenance
and monitoring obligations for that performance standard provided that releasing the Sponsors
from those obligations does not adversely affect the remainder of the Bank, or affect credits
already sold, used, or transferred to date. If the BOC approves such a release from the Sponsors'
obligations, and subsequent Bank conditions cause previously satisfied performance standards to
MBI Ch3_Perf Stds_050106.doc
Chapter 3 May 2006
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
not be met, any previously awarded credits not yet sold, used, or transferred for that performance
standard that is no longer met shall be removed from the Bank ledger, and any credits already
sold, used, or transferred for that performance standard will be replaced with unsold, unused, and
untransferred credits. If there are insufficient unsold, unused, and untransferred credits to
replace those removed credits, the Sponsors shall implement other appropriate compensatory
mitigation approved by the Corps and Ecology, following consultation with the other BOC
members.
If more than one performance standard of the Bank fails to comply with the requirements of this
Agreement for more than one year, and that failure adversely affects the ability of the Bank to
achieve its goals or objectives, and if the Sponsor does not make a reasonable effort to bring the
Bank into compliance with this Agreement, the BOC may terminate this Agreement.
3.5 MAINTENANCE DURING THE ESTABLISHEMENT PHASE
General maintenance will be performed throughout the year to address conditions that may limit
the success of the Bank and attainment of performance standards and objectives. WSDOT is
responsible for all site maintenance activities throughout the establishment phase of the Bank.
Maintenance activities will include, but are not limited to, vegetative maintenance (including
replanting, repair of any areas subject to erosion, weed control around plantings, mowing,
control of invasive species, control and discouragement of voles, beaver and deer foraging on
plants) and general maintenance (including fence repair, road and trail maintenance as necessary,
clean -out of culverts, monitoring of the water control structures, and clean-up of trash).
MBI Ch3_PWSWs_0W106.doc
Chapter 3 May 2W6
Project Goal, Objectives, and Performance Standards Page 3-4
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Table 3-1
Summary of Performance Standards, Monitoring Methods, Related Objectives, Functions and Values, and Function Attributes (Riverine) For Units A and B
Units A and B Performance Standards
Grading/Hydrology
A/13-1. As -Built drawings will document that site
grading and planting has been completed as
shown on the Unit A and B plans.
A/B-2A. In Year 3, soils will be saturated to the
surface, or standing water will be present 12
inches below the surface or less for at least 10%
of the growing season. *** The extent of over -bank
flooding from Springbrook Creek during late winter
and/or early spring storm -events (January through
March) will also be documented in Units A and B.
A/113-2113. In Years 3, 5, and 10, no more than 10% of
the sites will be un-vegetated and permanently
inundated based on observations made during the
summer monitoring visit.
A/B-2C. In Years 5 and 10, at least 0.12 acre of
wetland will be present in the Wetland
Re -Establishment areas (bottom of the berm
breaches) of Units A and B. Also, a separate
wetland delineation will be done to verify that
mitigation actions have not reduced the extent of
existino wetlands in Units A and B.
A/B-3A. In Year 1, the Wetland Tree/Shrub planting
areas will each have at least 2,000 stems of living
native woody vegetation per acre.
A/113-313. In Year 1, the Upland and Riparian Upland
planting areas will each have at least 1,200 stems
of living native woody vegetation per acre.
A/B-4. In Year 3, the Wetland Tree/Shrub planting
areas will each have at least 2,000 stems of living
native woody vegetation per acre.
A/B-5A. In Year 5, native woody vegetation within
the Wetland Tree/Shrub planting areas will
provide at least 50% aerial cover.
A/B-5B. In Year 5, at least 3 native woody species
will provide at least 5% aerial cover each within
the Wetland Tree/Shrub planting areas.
A/B-5C. In Year 5, native woody vegetation within
the Upland and Riparian Upland planting areas
will provide at least 30% aerial cover.
A/113-51). In Year 5, at least 3 native woody species
will provide at least 3% aerial cover each within
the Upland and Riparian Upland planting areas.
A/113-6. In Year 7, native woody vegetation within the
Wetland Tree/Shrub planting areas will provide at
least 60% aerial cover.
A/B-7A. In Year 10, native woody vegetation within
Wetland Tree/Shrub planting areas will provide at
least 75% aerial cover.
A/113-7113. In Year 10, at least 2 native woody species
will provide at least 10% aerial cover each within
the Wetland Tree/Shrub planting areas.
A/B-7C. In Year 10, native woody vegetation within
the Upland and Riparian Upland planting areas
will provide at least 50% aerial cover.
A/113-71). In Year 10, at least 2 native woody species
will provide at least 7% aerial cover each within
the Upland and Riparian Upland planting areas.
A/B-8. In Years 5 and 10, planting hummocks
located within the Wetland Tree/Shrub planting
areas will have at least one living native tree.
A/113-9. In Years 5 and 10, Himalayan blackberry will
not cover more than 20% of the buffers and
riparian areas at the site. In Years 1 through 10,
remove all Japanese knotweed, English ivy, and
purple loosestrife identified within Units A and B.
Woody Habitat Structures
A/13-10. In Year 1, at least 35 woody habitat
structures (vertical snags, brush piles, and/ or
LWD) will be present in Units A and B.
Monitoring Tasks/Methods
After construction is completed, As -Built drawings
will be submitted to document the completion and
accuracy of grading work. Monitoring will confirm
conditions depicted in the As -Built drawings.
Hydrology will be verified by visual inspection of
multiple hand -dug pits conducted during multiple
site visits in the early growing season. Site visits
during the wet season to correlate crest gages
with the upstream USGS gage station, automated
monitoring equipment, or other appropriate
method will be used to document the extent of
over -bank flooding in Units A and B.
During the summer formal monitoring visit visual
observations or another appropriate method will
be used to determine the amount of the site that
exists as permanently inundated un-vegetated
open water. Use current aerial photos, if available.
Wetland conditions will be demonstrated by
wetland delineation, performed according to the
1987 Corps of Engineers Wetland Delineation
Manual and the 1997 Washington State Wetland
Identification Manual, by a qualified WSDOT
biologist in Years 5 and 10.
In Years 1 and 3, determine density of living stems
per acre using randomly placed unequal -area belt
transects as described by Stehman and Salzer
(2000) or other statistically appropriate method.
In Years 5, 7, and 10, determine woody cover by
species in the Wetland Tree/Shrub, Riparian
Upland, and Upland planting areas using
randomly placed sample units and line intercept
method as described in Elzinga et al. (1998) or
other statistically appropriate method.
In Years 5 and 10, each planting hummock will be
visited to verify that one living native tree is
present per hummock.
In Years 5 and 10, determine cover of Himalayan
blackberry on the buffers and riparian areas at the
site using randomly placed sample units and line
or point intercept method as described in Elzinga
et al. (1998) or other statistically appropriate
method. Annual visual inspections of the site will
locate target species and they will be removed
annually.
The number of habitat structures (vertical snags,
brush piles, and LWD) will be counted and
documented in monitoring reports in Year 1.
Related Functions and I Function Attributes from Hruby
Objectives Values* et al. (1999) **
1, 2, 3, 4, 5 Wetland Area
Hydrologic
Water Quality
Habitat
Wetland Area.
Width of wetland to stream.
2, 3, 4 Hydrologic Number of vegetation classes.
Water Quality Cover by woody vegetation.
Habitat Canopy closure over wetland.
Canopy closure over stream.
Number of vegetation strata.
Number of native plant species.
Number of plant assemblages.
Buffer condition.
Mature woody vegetation.
Habitat LWD.
Snags.
* See Table 2-3 for information on how the performance standards relate to functional lift in the categories listed.
**Some attributes listed are not contained in WAFAM, but address variables not considered in the models (i.e., wetland area, education).
***A qualifying year must have rainfall that meets or exceeds the thirty year average as measured at SEAITAC International Airport.
CH 3 1 U17_030206.doc
Chapter 3 May 2006
Project Goal, Objectives, and Performance Standards Page 3-4
FINAL DRAFT
brook Creek Wetland and Habitat Mith!ation Bank Instrument
Table 3-2
Summary of Performance Standards, Monitoring Methods, Related Objectives, Functions and Values, and Function Attributes (Depressional) For Unit C
Unit C Performance Standards
Grading/Hydrology
C-1. As -Built drawings will document that site
grading and planting has been completed as
shown on the Unit C plans.
C-2A. In Year 3,soils will be saturated to the
surface, or standing water will be present 12
inches below the surface or less for at least 10%
of the growing season. ***
C-2B. In Years 5 and 10, at least 9.27 acres of
wetland will be present within the Wetland
Re -Establishment area in Unit C.
C-3A. In Year 1, the Wetland Tree/Shrub planting
areas will have at least 2,000 stems of living
native woody vegetation per acre.
C-313. In Year 1, The Upland planting areas will
have at least 1,200 stems of living native woody
vegetation per acre.
C-3C. In Years 1, 5 and 10, the Forested Wetland
Enhancement areas will contain at least 70 living
native conifers per acre.
C-4A. In Year 3, the Wetland Tree/Shrub planting
areas will have at least 2,000 stems of living
native woody vegetation per acre.
C46. In Year 3, the Wetland Enhancement Type I
areas will have at least 100 conifers per acre.
C-5A. In Year 5, native woody vegetation within the
Wetland Tree/Shrub planting areas will provide at
least 50% aerial cover.
C-513. In Year 5, at least 3 native woody species will
provide at least 5% aerial cover each within the
Wetland Tree/Shrub planting areas.
C-5C. In Year 5, native woody vegetation within the
Upland planting areas will provide at least 30%
aerial cover.
C-5D. In Year 5, at least 3 native woody species will
provide at least 3% aerial cover each within the
Upland planting areas.
C-6A. In Year 7, native woody vegetation within the
Wetland Tree/Shrub planting areas will provide at
least 60% aerial cover.
C-6B. In Year 7, the Wetland Enhancement Type I
areas will have at least 75 conifers per acre.
C-7A.In Year 10, native woody vegetation within the
Wetland Tree/Shrub planting areas will provide at
least 75% aerial cover.
C-7B. In Year 10, at least 2 native woody species
will provide at least 10% aerial cover each within
the Wetland Tree/Shrub planting areas.
C-7C. In Year 10, native woody vegetation within
the Upland planting areas will provide at least
50% aerial cover.
C-711). In Year 10, at least 2 native woody species
will provide at least 7% aerial cover each in the
Upland planting areas.
C-8. In Years 5 and 10, Himalayan blackberry will
not cover more than 20% of the Forested Wetland
Enhancement, Upland planting areas, and buffers
at the site, and not more than 10% in the Wetland
Re -Establishment Area. In Years 1 through 10,
remove all Japanese knotweed, English ivy, and
purple loosestrife identified within Unit C.
Woody Habitat Structures
C-9. In Year 1, at least 50 woody habitat structures
(vertical snags, brush piles, and/or LWD) will be
present within Unit C.
Monitoring Tasks/Methods
After construction is completed, As -Built drawings
will be submitted to document the completion of
grading and planting work. Monitoring will confirm
conditions depicted in the As -Built drawings.
Visual inspection of multiple hand -dug pits
conducted during multiple site visits in the early
growing season or other appropriate methodology.
Wetland conditions will be demonstrated by
wetland delineation, performed according to the
1987 Corps of Engineers Wetland Delineation
Manual and the 1997 Washington State Wetland
Identification Manual, by a qualified WSDOT
biologist in Years 5 and 10.
In Year 1, determine density of living stems per
acre using randomly placed unequal -area belt
transects as described by Stehman and Salzer
(2000) or other statistically appropriate method.
In Years 1, 5, and 10 determine the density of
living conifers within the Forested Wetland
Enhancement areas using randomly placed
unequal -area belt transects as described by
Stehman and Salzer (2000) or other statistically
appropriate method.
In Year 3, determine density of living stems per
acre using randomly placed unequal -area belt
transects as described by Stehman and Salzer
(2000) or other statistically appropriate method.
In Year 3, determine density of living conifers per
acre using randomly placed unequal -area belt
transects as described by Stehman and Salzer
(2000) or other statistically appropriate method.
In Years 5 and 7, determine woody cover by
species in the Tree/Shrub planting areas, and in
Year 5 in the Upland planting areas using
randomly placed sample units and line intercept
method as described in Elzinga et al. (1998) or
other statistically appropriate method.
In Year 3, determine density of living conifers per
acre using randomly placed unequal -area belt
transects as described by Stehman and Salzer
(2000) or other statistically appropriate method.
In Year 10, determine woody cover by species in
the Wetland Tree/Shrub and Upland planting
areas using randomly placed sample units and
line intercept method as described in Elzinga et al.
(1998) or other statistically appropriate method.
In Years 5 and 10, determine cover of Himalayan
blackberry on the specified portions of the site
using randomly placed sample units and line or
point intercept method as described in Elzinga et
al. (1998) or other statistically appropriate method.
Annual visual inspections of the site will locate
taroet species and thev will be removed annually.
Woody habitat structures will be counted and
documented in monitoring reports.
Related Functions and Function Attributes from Hru
Objectives Values * et al. (1999) **
1, 2, 3, 4 Water Quality Wetland area.
Hydrologic Area seasonally inundated.
Habitat Number of water regimes.
Number of water depths.
2, 3, 4 Hydrologic Number of vegetation classes.
Water Quality Cover by woody vegetation.
Habitat Canopy closure over wetland.
Number of vegetation strata.
Number of native plant species.
Number of plant assemblages.
Vegetation class interspersion.
Mature woody vegetation.
Buffer condition.
Habitat LWD.
Snags.
* See Table 2-4 for information on how the performance standards relate to functional lift in the categories listed.
**Some attributes listed are not contained in WAFAM, but address variables not considered in the models (i.e., wetland area, education).
*** A qualifying year must have rainfall that meets or exceeds the thirty year average as measured at SEA/TAC International Airport.
CH 31 W 7_030206.doc
Chapter 3 May 2006
Project Goal, Objectives, and Performance Standards Page 3-5
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Table 3-3
Summary of Performance Standards, Monitoring Methods, Related Objectives, Functions and Values, and Function Attributes (Depressional) For Unit D
Unit D Performance Standards
Monitoring Tasks/Methods
Related
Functions7et
Function Attributes from Hruby
Objectives
Values*
al. (1999)**
Grading/Hydrology
D-1A. As -Built drawings will document that the
After construction is completed, As -Built drawings
2,3
Hydrologic
Area seasonally inundated.
constructed conveyance pipe at the north end of
will be submitted to document the completion of
Water Quality
Number of water regimes.
Unit D has been installed and is functioning as
minor grading, planting, and pipe installation work.
intended and planting has been implemented per
Monitoring will confirm conditions depicted in the
the plan.
As -Built drawings.
D-18. In Years 3 and 7, there will be inundation
In Years 3, 5, 7, and 10, photos will be taken on
present in the northern portion of Unit D on the
June 15th to document the presence of inundation
151h of June.
in the Northern portion of Unit D. To qualify the
water year in question must be within one
standard deviation of the 30-year average rainfall
(or greater) as measured at SEA/TAC
International Airport.
Vegetation
D-2A. In Year 1, the Wetland Tree/Shrub planting
In Year 1, determine the density of living native
3,4
Water Quality
Number of vegetation strata.
area (area disturbed by grading and installation of
woody species within the disturbed area using
Habitat
Number of native plant species.
the conveyance pipe) will have at least 2,000
randomly placed unequal -area belt transects as
Number of plant assemblages.
living stems per acre.
described by Stehman and Salzer (2000) or other
Understory vegetation.
statistically appropriate method
D-2B. In Years 1, 5, and 10, the Forested Wetland
In Years 1, 5, and 10, determine the density of
Enhancement areas will contain at least 70 living
living conifers within the Forested Wetland
native conifers per acre.
Enhancement areas using randomly placed
unequal -area belt transects as described by
Stehman and Salzer (2000) or other statistically
appropriate method.
D-3. In Years 5 and 10, the aerial cover of
In Years 5 and 10, determine the aerial cover of
Himalayan blackberry will not exceed 20% of the
Himalayan blackberry on the site using randomly
site. In Years 1 through 10, remove all Japanese
placed sample units and line or point intercept
knotweed, English ivy, and purple loosestrife
method as described in Elzinga et al. (1998) or
identified within Unit D.
other statistically appropriate method. Annual
visual inspections of the site will locate target
species and they will be removed annually.
Woody Habitat Structures
D-4. In Year 1, at least 2 woody habitat structures
Woody habitat structures will be counted and
4
Habitat
Brush piles.
(brush piles) will be present within Unit D.
documented in monitoring reports.
* See Table 2-5 for information on how the performance standards relate to functional lift in the categories listed.
**Some attributes listed are not contained in WAFAM, but address variables not considered in the models (i.e., wetland area, education).
CH 31107_030206.doc
Chapter 3 May 2006
Project Goal, Objectives, and Performance Standards Page 3-6
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Table 3-4
Summary of Performance Standards, Monitoring Methods, Related Objectives, Functions and Values, and Function Attributes (Riverine) For Unit E
Unit E Performance Standards
Grading/Hydrology
E-1. As -Built drawings will document site grading
and planting has been completed as shown on the
Unit E plans.
E-2A. In Year 3, soils will be saturated to the
surface, or standing water will be present 12
inches below the surface or less for at least 10%
of the growing season. ***
E-2113. In Years 3, 5, and 10, no more than 10% of
the sites will be un-vegetated and permanently
inundated based on observations made during the
summer monitoring visit.
E-2C. In Years 5 and 10, at least 8.37 acres of
wetland will be present within the Wetland
Re -Establishment area of Unit E.
E-3A. In Year 1, the Wetland Tree/Shrub planting
areas will have at least 2,000 stems of living
native woody vegetation per acre.
E-36. In Year 1, the Upland and Riparian Upland
planting areas will have at least 1,200 stems of
living vegetation per acre.
E-3C. In Years 1, 5, and 10, the Forest
Underplanting area will have at least 70 living
conifers per acre.
E-4. In Year 3, the Wetland Tree/Shrub planting
areas will have at least 2,000 stems of living
native woody vegetation per acre.
E-5A. In Year 5, native woody vegetation within the
Wetland Tree/Shrub planting areas will provide at
least 50% aerial cover.
E-5113. In Year 5, at least 3 native woody species will
provide at least 5% aerial cover each within the
Wetland Tree/Shrub planting areas.
E-5C. In Year 5, native woody vegetation within the
Upland and Riparian Upland planting areas will
provide at least 30% aerial cover.
E-51). In Year 5, at least 3 native woody species will
provide at least 3% aerial cover each within the
Upland and Riparian Upland planting areas.
E-6. In Year 7, native woody vegetation within the
Wetland Tree/Shrub planting areas will provide at
least 60% aerial cover.
E-7A. In Year 10, native woody vegetation within the
Wetland Tree/Shrub planting areas will provide at
least 75% aerial cover.
E-7113. In Year 10, at least 2 native woody species
will provide at least 10% aerial cover each within
the Wetland Tree/Shrub planting areas.
E-7C In Year 10, native woody vegetation in the
Upland and Riparian Upland planting areas will
provide at least 50% aerial cover.
E-71). In Year 10, at least 2 native woody species
will provide at least 7% aerial cover each within
the Upland and Riparian Upland planting areas.
E-8. In Years 5 and 10, the aerial cover of
Himalayan blackberry will not exceed 20% of the
buffers, uplands, and riparian areas on the site,
and not more than 10% of the Wetland Re -
Establishment Area. In Years 1 through 10,
remove all Japanese knotweed, English ivy, and
purple loosestrife identified within Unit E.
Woody Habitat Structures
E-9. In Year 1, at least 40 woody habitat structures
(vertical snags, brush piles, and/or LWD) will be
present in Unit E.
Monitoring Methods
After construction is completed, As -Built drawings
will be submitted to document the completion of
grading and planting work. Monitoring will confirm
conditions depicted in the As -Built drawings.
Hydrology will be verified in Year 3 by visual
inspection of multiple hand -dug pits conducted
during multiple site visits in the early growing
season.
During the summer formal monitoring visit visual
observations or another appropriate method will
be used to determine the amount of the site that
exists as permanently inundated un-vegetated
open water. Use current aerial photos, if available.
Wetland conditions will be demonstrated by
wetland delineation, performed according to the
1987 Corps of Engineers Wetland Delineation
Manual and the 1997 Washington State Wetland
Identification Manual, by a qualified WSDOT
biologist in Years 5 and 10.
Related Functions and Function Attributes from Hruby
Objectives Values* et al. (1999)**
1, 2, 3, 4, 5 Hydrologic Flood storage capacity.
Water Quality Number of hydrologic regimes.
Habitat Wetland area.
Wetland width relative to creek.
Wetland size relative to basin.
Area seasonally inundated.
In Year 1, determine density of living stems per 2, 3, 4 Hydrologic
acre using randomly placed unequal -area belt Water Quality
transects as described by Stehman and Salzer Habitat
(2000) or other statistically appropriate method.
In Years 1, 5, and 10 determine the density of
living conifers within the Forest Under -planting
areas using randomly placed unequal -area belt
transects as described by Stehman and Salzer
(2000) or other statistically appropriate method.
In Year 3, determine density of living stems per
acre using randomly placed unequal -area belt
transects as described by Stehman and Salzer
(2000) or other statistically appropriate method.
In Years 5, 7 and 10, determine woody cover by
species in the Wetland Tree/Shrub planting areas,
and in Years 5 and 10 in the Upland and Riparian
Upland planting areas using randomly placed
sample units and line intercept method as
described in Elzinga et al. (1998) or other
statistically appropriate method.
In Years 5 and 10, determine the aerial cover of
Himalayan blackberry on the site using randomly
placed sample units and line or point intercept
method as described in Elzinga et al. (1998) or
other statistically appropriate method Annual
visual inspections of the site will locate target
species and thev will be removed annually.
Woody habitat structures will be counted and
documented in monitoring reports.
Habitat
* See Table 2-6 for information on how the performance standards relate to functional lift in the categories listed.
**Some attributes listed are not contained in WAFAM, but address variables not considered in the models (i.e., wetland area, education).
*** A qualifying year must have rainfall that meets or exceeds the thirty year average as measured at SEAITAC International Airport.
Number of vegetation classes.
Cover by woody vegetation.
Canopy closure over wetland.
Canopy closure over stream.
Number of vegetation strata.
Number of native plant species.
Number of plant assemblages.
Vegetation class interspersion.
Mature woody vegetation.
Buffer condition.
LWD.
Snags.
Chapter 3 March 2006
Project Goal, Objectives, and Performance Standards Page 3-7
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
4.0 BANK OPERATION
4.1 CREDIT DETERMINATION
Credits are the "currency" of a mitigation bank. The value of credits that a mitigation
bank generates equals its net ecological benefit. The 129.27-acre Springbrook Bank
includes 116.91 acres that qualify for bank credit. The remaining 12.37 non-credit acres
have been designated for protection setback and the Trail Zone to minimize disturbances
from adjacent roads, development, and the trail through Unit A. Units D and E each have
an existing 20-foot utility easement inside the parcel boundary that will not generate
mitigation credit (see Figures 2-4 and 2-3). The 45.13 credits to be generated at
Springbrook Bank represents the number of acres of impacts to Category II wetlands
(Hruby 2004) for which the bank could be used as compensation (Table 4-1). These
mitigation credits will become available as performance standards and other measures are
achieved (see Tables 3-1 through 3-4 and Table 4-3).
Table 4-1. Credit Potential
Mitigation Treatment
Acreage Ratios"
Mitigation Credits"
Unit A
Unit B
Unit C
Unit D
Unit E
Total
Wetland Re -Establishment
17.79
1:1
0.05
0.12
9.27
--
8.35
17.79
Wetland Rehabilitation
52.16
3:1
6.64
10.39
0.35
-
-
17.39
Wetland Enhancement - Type 1
4.69
4:1
-
--
1.17
--
-
1.17
Wetland Enhancement - Type II
2.63
5:1
--
--
--
0.53
--
0.53
Forested Wetland Enhancement
25.23
5:1
-
--
4.65
0.40
--
5.05
Riparian Upland Enhancement
6.55
4:1
0.16
0.37
--
--
1.11
1.64
Upland Habitat Enhancement
7.80
5:1
-
--
1.56
--
--
1.56
Buffer Enhancement
9.70
--
Trail Zone
2.66
--
--
--
--
--
--
--
Totals
129.22
--
6.86
10.88
17.00
0.93
9.46
45.13
* 1 he ratio of acreage to credits is the number of credits established per acre of mitigation activity in first column.
** The number of mitigation credits that Springbrook Bank will generate for each mitigation treatment. Each credit can
compensate for the loss of a typical acre of Category II wetland.
4.2 APPROVING PERFORMANCE STANDARDS FOR CREDIT RELEASE
Springbrook Bank will generate 45.13 credits that will be eligible for release as the
associated performance standards are met and approved by the BOC (Tables 3-1 through
3-4), with the exception that no credits may be released until WSDOT and the City
complete the development of a BOC-approved Memorandum of Agreement and
Instrument, and until a BOC-approved conservation easement is placed on the property
title and properly recorded with King County. Once a credit is released, WSDOT or the
City may sell or transfer that credit at any time, subject to the provisions of this
Instrument.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Credits will be released from the bank according to Table 4-3 provided that WSDOT and
the City demonstrate success in meeting the subject performance standards and are
compliant with the provisions of this Instrument. To obtain release of credits associated
with a particular performance standard, WSDOT and the City will provide the BOC with
documentation of success, usually in the form of a scheduled monitoring report. Each
monitoring report will include a letter requesting the release of the credits associated with
performance standards that have been met. This is to be reviewed by the BOC within 60
days. If a BOC agency is not able to comment during the 60-day period and other BOC
members have approved the release, the available agencies will respond on behalf of the
entire BOC.
Upon approval from the Corps and Ecology, following consultation with the other BOC
members the credits are available for release and should be added to the ledger sheet. If
Springbrook Bank is not able to meet a particular performance standard by the year
indicated, WSDOT and the City may submit documentation of successful achievement of
those performance standards during a subsequent year, the BOC will give full
consideration to the release of appropriate credits for sale, use, or transfer without
reduction or other penalty. The BOC may, at its discretion, release partial credit for
partial accomplishment of a performance standard. Bank credits may be used, subject to
the approval of the regulatory agencies with jurisdiction over projects that desire to
satisfy mitigation obligations through use of the Springbrook Bank, to compensate for
authorized permanent or temporary impacts, as well as to resolve enforcement or permit
compliance actions such as replacing previously implemented project -specific mitigation
that has partially or completely failed.
Public and private proponents of activities regulated under Sections 401 and 404 of the
Clean Water Act (33 U.S. Code §§ 1341, 1344), Section 10 of the Rivers and Harbors
Act of 1899 (33 U.S. Code § 403), Washington State Water Pollution Control Act
(Chapter 90.48, RCW), Shoreline Management Act (RCW 90.58), Growth Management
Act (RCW 36.70A), Hydraulic Code (RCW 75.20), and other Federal, State, and localV
authorities may be eligible to use the Bank as mitigation for unavoidable impacts. The
Bank will be eligible to serve public and private end users by providing potential advance
compensatory mitigation for authorized impacts to regulated areas that require mitigation
to settle enforcement claims, off -site Natural Resource Damage Assessment offsets, ESA
Section 9 violations (relating to threatened and endangered species issues affecting,
among others, Puget Sound salmonids), and similar uses. The Bank is intended to
provide replacement of lost functions and values including: wetlands, stream channel
and endangered fisheries habitat, riparian habitat, and upland/buffer habitat.
If the institution of an adaptive management or remedial action plan as described in
Section 3.4 of this Instrument causes delay in the achievement of a performance standard,
the timeline for achievement of each subsequent milestone for that performance standard
will be deferred for a like interval, unless otherwise specifically approved by the Corps
and Ecology following consultation of the other BOC members. The BOC, in
consultation with the Sponsors, will determine what remedial actions are necessary to
correct the situation and direct their performance prior to the release of any additional
mitigation credits.
MBI Ch4_Bank0perabon_050106.doc
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Sprin;,brook Creek Wetland and Habitat Mitigation Bank Instrument
4.3 USE OF CREDITS
Springbrook Bank credits were developed to compensate at a 1:1 ratio for adverse
impacts (including direct loss or indirect impacts) to a Category II wetland. The number
of credits required to compensate for each acre of Category I, III, or IV wetland impact
will differ because wetland categories have a different level of function on a per -acre
basis (see Table 4-2). Wetland categories will be determined using the Washington State
Wetland Rating System_for Western Washington (Hruby 2004).
Table 4-2. Credits Required for Wetland Impacts
Category of Impacted Wetland
Credit Required per Impact Acre
Case -by -Case
II
1.0
111
0.85
IV
0.70
For example, if a proposed project would impact 3 acres of Category II wetland, 3 credits
would be withdrawn from the bank to compensate for that impact. If a proposed project
would impact 3 acres of Category III, 2.55 credits would be withdrawn. Credits may
potentially be used as compensation for impacts to non -wetland waters of the U.S. with
specific approval of the agencies with jurisdictional authority over the project. Credits
required per impact acre would be determined on a per -project basis due to the variability
of non -wetland areas.
An applicant seeking a permit for a project with adverse impacts to the aquatic
environment within the service area must generally obtain the approval of each regulatory
agency with jurisdiction over that project, in order to use the Bank as a source of
compensatory mitigation. To receive approval to use the Bank, the applicant must
demonstrate to the satisfaction of the pertinent regulatory agencies that the project
complies with all applicable requirements pertaining to alternatives and mitigation
sequencing and that purchasing credits from the Bank for compensatory mitigation would
be in the best interest of the environment. Specifically, a permit applicant must generally
be able to demonstrate to the satisfaction of the involved regulatory agencies that:
1. There is no practicable alternative to adversely impacting the water body,
critical area, buffer, or other regulated area.
2. All appropriate and practicable measures to minimize adverse impacts to
the aquatic ecosystem have been considered and included in the project.
3. All appropriate and practical on -site compensatory mitigation for
unavoidable adverse impacts has been considered for the project.
Other types of credit users may include, but are not necessarily limited to, transfers made
that are not associated with any one particular project or impact (i.e., "good will"
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
transfers), transfers to natural resource stewards resulting from expenditures from in -lieu -
fees, or similar type funds; and credit sales made for the purpose of brokerage.
WSDOT and the City reserve the right to develop mitigation credits as compensation for
impacts to flood storage and wetland and/or riparian buffer at Springbrook Bank with no
effect on the value or number of credits established by this Instrument, provided that the
generation of such credits will not conflict with the provisions of this Instrument.
4.3.1 Credit Release Flexibility
Credits may not be released sooner than specified in Table 4-3, except in extraordinary
situations with the written approval of the Corps and Ecology, in consultation with the
other members of the BOC. If exceptional circumstances unforeseen during the
development and implementation of Springbrook Bank arise such that the public interest
would be better served by earlier than scheduled release of credits from the bank, the City
and WSDOT may request the BOC approve a modification in the Credit Release
Schedule (Table 4-3). In such a circumstance, the Sponsors must submit a written
request that clearly explains the nature of the exceptional circumstances and demonstrates
how the requested change in the credit release schedule would serve the public interest.
If the BOC concurs that the early release of credits would serve the public interest and
not violate existing mitigation banking rules and regulations, then they may approve the
request. This approval will become a part of the Instrument.
MBI Ch4_BankOperation_050106.doc
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Sgringbrook Creek Wetland and Habitat Mitigation Bank Instrument
Table 4-3: Credit Release Schedule for Sorinabrook Bank
Performance Standard
Number of Credits to be Released By Year
0* 1 3
5 7 10 Total
Administrative Measures 10 % of total
Sign MBI and establish Conservation Easement 4.5
4.5
Grading/Hydrology (31 % of total)
A/113-1. As -Built drawings will document that site grading and planting has been completed as shown on the Unit A and B plans.
1.5
1.5
AIB-2A. In Year 3, soils will be saturated to the surface, or standing water will be present 12 inches below the surface or less for at least
10% of the growing season. ** The extent of over -bank flooding from Springbrook Creek during late winter and/or early spring storm -events
(January throu h March will also be documented in Units A and B.
0.25
0.25
AI113-2113. In Years 3, 5, and 10, no more than 10% of the sites will be un-vegetated and permanently inundated based on observations made
during the summer monitoring visit.
0.25
0.25
0.1
0.6
A/B-2C. In Years 5 and 10, at least 0.12 acre of wetland will be present in the Wetland Re -Establishment areas of Units A and B. A
separate wetland delineation will be done to verify that mitigation actions have not reduced the extent of existing wetlands in Units A and B.
0.1
0.1
0.2
C-1. As -Built drawings will document that site grading and planting has been completed as shown on the Unit C plans.
2.5
2.5
C-2A. In Year 3, soils will be saturated to the surface, or standing water will be present 12 inches below the surface or less for at least 10%
of the growing season. **
1
1
C-2113. In Years 5 and 10, at least 9.27 acres of wetland will be present within the Wetland Re -Establishment area in Unit C.
1.25
0.4
1.65
D-1A. As -Built drawings will document that the constructed conveyance pipe at the north end of Unit D has been installed and is functioning
as intended and planting has been implemented per the plan.
0.25
0.25
D-113. In Years 3 and 7, there will be inundation present in the northern portion of Unit D on the 151h of June. **
0.25
0.2
0.45
E-1. As -Built drawings will document site grading and planting has been completed as shown on the Unit E plans.
2.5
2.5
E-2A. In Year 3, soils will be saturated to the surface, or standing water will be present 12 inches below the surface or less for at least 10%
of the growing season. **
1
1
E-26. In Years 3, 5, and 10, no more than 10% of the sites will be un-vegetated and permanently inundated based on observations made
during the summer monitoring visit.
0.25
0.25
E-2C. In Years 5 and 10, at least 8.37 acres of wetland will be present within the Wetland Re -Establishment area of Unit E.
1.25
0.19
1.44
Vegetation (56% of total)
A/B-3A. In Year 1, the Wetland Tree/Shrub planting areas will each have 2,000 stems of living native woody vegetation per acre.
1
1
A/B-3B. In Year 1, the Upland and Riparian Upland planting areas will each have 1,200 stems of living native woody vegetation per acre
0.5
0.5
A/B4. In Year 3, the Wetland Tree/Shrub planting areas will each have 2,000 stems of living native woody vegetation per acre.
1
1
A/B-5A. In Year 5, native woody vegetation within the Wetland Tree/Shrub planting areas will provide 50% aerial cover.
.90
1
A/B-5B. In Year 5, at least 3 native woody species will provide at least 5% aerial cover each within the Wetland Tree/Shrub planting areas.
1
1
0.25
1
1 0.25
A/B-5C. In Year 5, native woody vegetation within the Upland and Riparian Upland planting areas will provide 30% aerial cover.
0.1
0.1
A/B-5D. In Year 5, at least 3 native woody species will provide at least 3% aerial cover each in Upland and Riparian Upland planting areas.
0.1
0.1
A/13-6. In Year 7, native woody vegetation within the Wetland Tree/Shrub planting areas will provide 60% aerial cover.
2
2
A/B-7A. In Year 10, native woody vegetation within Wetland Tree/Shrub planting areas will provide 75% aerial cover.
0.4
0.4
A/B-7B. In Year 10, at least 2 native woody species will provide at least 10% aerial cover each in the Wetland Tree/Shrub planting areas.
1
0.15
0.15
AIB-7C. In Year 10, native woody vegetation within the Upland and Riparian Upland planting areas will provide 50% aerial cover.
0.1
0.1
A/B-7D. In Year 10, at least 2 native woody species will provide at least 7% aerial cover each in Upland and Riparian Upland planting areas.
0.1
0.1
A/B-8. In Years 5 and 10, planting hummocks located within the Wetland Tree/Shrub planting areas will have at least one living native tree.
1
0.5
0.25
0.75
A/13-9. In Years 5 and 10, Himalayan blackberry will not cover more than 20% of the buffers and riparian areas at the site. In Years 1 - 10, remove
all Japanese knotweed, English ivy, and purple loosestrife identified within Units A and B.
0.1
0.1
0.2
-3A. in Year 1, the Weiland Tree/Shrub pianting areas will have 2,000 siems of living native woody vegetation per acre.
1
1
C-3113. In Year 1, the Upland planting areas will have 1,200 stems of living native woody vegetation per acre.
0.25
0.25
C-3C. In Years 1, 5, and 10, the Forested Wetland Enhancement areas will contain at least 70 living native conifers per acre.
0.55
0.5
0.25
1.3
C-4A. In Year 3, the Wetland Tree/Shrub planting areas will have 2,000 stems of living native woody vegetation per acre.
1
1
C4B. In Year 3, the Wetland Enhancement Type I areas will have at least 100 conifers per acre.
0.75
0.75
C-5A. In Year 5, native woody vegetation within the Wetland Tree/Shrub planting areas will provide 50% aerial cover.
1
1
C-5B. In Year 5, at least 3 native woody species will provide at least 5% aerial cover each within the Wetland Tree/Shrub planting areas.
0.25
0.25
C-5C. In Year 5, native woody vegetation within the Upland planting areas will provide 30% aerial cover.
0.25
0.25
C-5D. In Year 5, at least 3 native woodspecies will provide at least 3% aerial cover each within the Upland planting areas.
0.1
0.1
C-6A. In Year 7, native woody vegetation within the Wetland Tree/Shrub planting areas will provide 60% aerial cover.
2
2
C-6113. In Year 7, the Wetland Enhancement Type I areas will have at least 75 conifers per acre.
0.5
0.5
C-7A.In Year 10, native woody vegetation within the Wetland Tree/Shrub planting areas will provide 75% aerial cover.
0.4
0.4
C-7B. In Year 10, at least 2 native woody species will provide at least 10% aerial cover each within the Wetland Tree/Shrub planting areas.
0.15
0.15
C-7C. In Year 10, native woody vegetation within the Upland planting areas will provide 50% aerial cover.
0.1
0.1
C-7D. In Year 10, at least 2 native woody species will provide at least 7% aerial cover each in the Upland planting areas.
0.1
0.1
C-8. In Years 5 and 10, Himalayan blackberry will not cover more than 20% of the Forested Wetland Enhancement and other upland areas of the
site, and not more than 10% in the Wetland Re -Establishment Area. In Years 1 -10, remove all Japanese knotweed, English ivy, and purple
loosestrife identified within Unit C.
0.1
0.1
0.2
D-2A. In Year 1, the Wetland Tree/Shrub planting area will have 2,000 stems of native living vegetation per acre.
0.1
0.1
D-2B. In Years 1, 5, and 10 the Forested Wetland Enhancement areas will contain at least 70 living native conifers per acre.
0.2
0.2
0.2
0.6
D-3. In Years 5 and 10, the aerial cover of Himalayan blackberry will not exceed 20% of the site. In Years 1 through 10, remove all Japanese
knotweed, English ivy, and purple loosestrife identified within Unit D.
0.1
0.1
0.2
E-3A. In Year 1, the Wetland Tree/Shrub planting areas will have 2,000 stems of living native woody vegetation per acre.
1
1
E-3113. In Year 1, the Upland and Riparian Upland planting areas will have 1,200 stems of living vegetation per acre.
10.25
0.25
E-3C. In Years 1, 5, and 10, the Forest Wetland Enhancement area will have 70 living conifers per acre.
0.25
0.1
0.1
0.45
E-4. In Year 3, the Wetland Tree/Shrub planting areas will have 2,000 stems of living native woody vegetation per acre.
1
1
E-5A. In Year 5, native woody vegetation within the Wetland Tree/Shrub planting areas will provide 50% aerial cover.
1
1
E-5113. In Year 5, at least 3 native woody species will provide at least 5% aerial cover each within the Wetland Tree/Shrub planting areas.
0.25
0.25
E-5C. In Year 5, native woody vegetation within the Upland and Riparian Upland planting areas will provide 30% aerial cover.
0.25
0.25
E-5D. In Year 5, at least 3 native woodspecies will provide at least 3% aerial cover each in the Upland and Riparian Upland planting areas.
0.1
0.1
E-6. In Year 7, native woody vegetation within the Wetland Tree/Shrub planting areas will provide 60% aerial cover.
2
2
E-7A. In Year 10, native woody vegetation within the Wetland Tree/Shrub planting areas will provide 75% aerial cover.
0.4
0.4
E-713. In Year 10, at least 2 native woody species will provide at least 10% aerial cover each within the Wetland Tree/Shrub planting areas.
0.15
0.15
E-7C In Year 10, native woody vegetation in the Upland and Riparian Upland planting areas will provide 50% aerial cover.
0.1
0.1
E-7D. In Year 10, at least 2 native woodspecies will provide at least 7% aerial cover each in Upland and Riparian Upland planting areas.
0.1
0.1
E-8. In Years 5 and 10, the aerial cover of Himalayan blackberry will not exceed 20% of the uplands on site, and not more than 10% of the Wetland
Re -Establishment Area. In Years 1 -10, remove all Japanese knotweed, English ivy, and purple loosestrife identified within Unit E.
0.1
0.1
0.2
Woody Habitat Structures (4% of total)
A/B-10. In Year 1, at least 35 woody habitat structures (vertical snags, brush piles, and/ or LWD) will be present in Units A and B.
0.5
0.5
C-9. In Year 1, at least 50 woody habitat structures (vertical snags, brush piles, and/or LWD) will be present within Unit C.
0.5
0.5
D-4. In Year 1, at least 2 woody habitat structures (brush piles) will be present within Unit D.
0.1
0.1
E-19. In Year 1, at least 40 woody habitat structures (vertical snags, brush piles, and/or LWD) will be present in Unit E.
0.5
0.5
Percent of Total Credits
10%
1 15%
1 15%
15%
20%
15%
10%
Totals
4.50
6.75
1 6.70
6.75
9.35
6.75
4.34
45.13
* Year 0 indicates as -built site conditions bised on site work completed in the second construction year.
A qualifying year must have rainfall V at meets or exceeds the thirty year average as measured at SEARAC International Airport.
Chapter 4
Bank Operation
CH 4 11 x17_030206.doc
March 2006
Page 4-4
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
4.4 ACCOUNTING PROCEDURES AND LEDGER MANAGEMENT
WSDOT shall establish and maintain for inspection and reporting purposes a ledger of all
credit transactions. WSDOT will maintain a ledger of the credits that are released through
the achievement of specified performance standards, as well as credits that are debited
through sale, use, or transfer. (Table 4-6). Each year, the City and WSDOT will provide
the BOC with a copy of the Springbrook ledger by March 31, until all credits are
expended. The City may maintain its own separate concurrent ledger to track its portion
of the credits, but WSDOT will retain responsibility for the master ledger detailing all
debits and credits associated with Springbrook Bank to satisfy BOC requirements and
comply with the CBMOA. When credits are to be withdrawn from the bank, any agencies
with jurisdiction over the debiting project's mitigation requirements and decisions will
coordinate the debiting of credits through the appropriate permit process.
The following information will be recorded in the ledger for each transaction:
1. Date of transaction.
2. Number of credits transacted.
3. For credits released for sale/use/transfer, reference the performance
standard(s) to which the released credits correspond.
4. For credit sales/use/transfers, include the name, address, and telephone
number of user/purchaser; permit or project number(s) and name of the
regulatory agency(ies) requiring permits; location of the project for
which the credits are being purchased; and a brief description of the
adverse project impacts requiring compensatory mitigation (e.g.,
nature, size and quality of aquatic resources affected).
5. For credits withdrawn from the ledger for reasons other than credit
sale/use/transfer, include the specific reason for withdrawal.
6. Number of credits available in the Bank at the time of transaction.
WSDOT will provide the BOC a copy of the bank ledger, by March 31 of each year,
showing a cumulative tabulation of all transactions at the Bank to date. This ledger will
be submitted in conjunction with the annual monitoring report until all credits have been
released and sold, used, or otherwise transferred; or until the BOC has accepted
Springbrook Bank's written certification that it has terminated all banking activity.
4.5 SITE COMPLIANCE MONITORING
During the establishment phase of the Bank, WSDOT, on behalf of itself and the City
will prepare and submit monitoring reports to the BOC by March 31 following each
monitoring year listed in Table 4-4. These reports will document the progress that has
been made towards achieving the performance standards, adaptive management actions,
and an overview of site progress.
A combination of formal and informal monitoring of the bank site will occur during the
establishment phase or until all performance standards are met, whichever occurs later.
Formal monitoring will consist of quantitative sampling techniques to address specific
performance standards listed in Tables 3-1 through 3-4, while informal monitoring will
consist of visual inspection of the mitigation area to identify any issues and necessary
adaptive management actions. Formal monitoring will occur once per specified year
MBI CM_BankOperabon_050106.doc
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Bank Operation Page 4-6
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
between June and September (see Table 4-4), informal monitoring may occur
periodically throughout the year (see Table 4-5). Additional formal monitoring visits
may be conducted in years not listed to address performance standards not achieved in
designated and/or prior years. The monitoring plan provides specific details about
methods and reporting requirements (see Appendix A).
Table 4-4. Formal Monitoring Table 4-5. Informal Monitoring
Monitorina Year FrPauenr_v Monitoring Year Frequency
Year 1
Annual Site Visit
Year 3
Annual Site Visit
Year 5
Annual Site Visit
Year 7
Annual Site Visit
Year 10
Annual Site Visit
Year 1
Quarterly Site Visits
Year 2
Quarterly Site Visits
Year 3
Quarterly Site Visits
Year 4
Quarterly Site Visits
Year 5
Quarterly Site Visits
Year 6
Annual Site Visit
Year 7
Annual Site Visit
Year 8
Annual Site Visit
Year 9
Annual Site Visit
Year 10
Annual Site Visit
WSDOT's Wetland Mitigation Monitoring staff will conduct the formal and informal
monitoring of Springbrook Bank during the establishment phase of the Bank. The City
will conduct site visits periodically during the long-term management phase using the
guidelines outlined in Section 5.2, and to gauge the need and scope for additional site
management activities. The WSDOT Monitoring Program conducts compliance
monitoring for many of WSDOT's compensatory wetland mitigation projects.
Compliance monitoring provides a means for tracking the development of WSDOT
mitigation projects over time, and for determining compliance with permits issued by
federal, state, local, or tribal jurisdictions. The Monitoring Program provides important
internal feedback role in mitigation site management and maintenance. This feedback
serves as an essential link in the internal adaptive management process, increasing the
overall success of mitigation sites.
WSDOT's Monitoring Program uses a variety of monitoring methods. Quantitative data
collection techniques are based on standard ecological and biostatistic methods. The
configuration, placement, and number of sample units (e.g., belt transects, plots, lines,
point -lines, point frames) required to address site -specific performance objectives will be
based on characteristics observed in the vegetative community and patterns of plant
distribution. Sample size analysis will be used to ensure data from an adequate number
of sample units has been obtained to meet the sampling objectives. Monitoring reports
will include a description of methods and sampling designs used to monitor the various
performance standards for the bank site (See Chapter 3).
The City and WSDOT will obtain the approval of Corps and Ecology, with consultation
of the other BOC members prior to altering any element of the monitoring plan. The
BOC may require additional monitoring, if necessary to demonstrate that certain
performance standards have been met.
M8ICh4_BankOperabon_050106.dce
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Bank Operation Page 4-7
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
BOC may require additional monitoring, if necessary to demonstrate that certain
performance standards have been met.
MBI Ch4_BankOperabon_050106.doc
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Bank Operation Page 4-8
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Table 4-6. Sample Accounting Ledger
I Date
Requirement Met Resulting in
Credit Release or Name and
Contact Info of Credit
User/Purchaser
Project Location and
Description of Impacts
Project Title/Permit #
and Issuing Agency
Debit* or
Credit
Amount
Total
Credits
Available
I
I
I
I
Debits are enclosed as parentheses.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
5.0 SITE PROTECTION AND MANAGEMENT
5.1 PROTECTION MECHANISMS
WSDOT and the City have taken actions to ensure that Springbrook Bank wetland, riparian, and
habitat functions and values will be protected in perpetuity. The actions include establishing a
conservation easement and encumbering the deed with the signed MBI.
5.1.1 Conservation Easement
The City will grant and record an appropriate conservation easement to dedicate in perpetuity the
property constituting each unit of the Bank that is to be created, restored, or enhanced for credit.
The conservation easement can not be removed or modified without written approval of the
BOC. Conveyance of any interest in the property will be subject to this conservation easement.
Use prohibitions reflected in the easement will preclude the site from being used for activities
that would be incompatible with the establishment and operation of the Bank. All restrictions
will be granted in perpetuity without encumbrances or other reservations, except those
encumbrances or reservations approved by the BOC and not adversely affecting the ecological
viability of the Bank. Any portion of the site not encumbered by the conservation easement will
not be included in the credit -generating area of the Bank.
The conservation easement will reflect that the site owner warrants that it will comply with all
applicable state and local requirements for controlling noxious weeds on the Bank site.
According to this conservation easement all structures, facilities, and improvements within the
Bank, including roads, trails and fences, that are merely incidental to the functionality of the
mitigation site but are necessary to the Bank management and maintenance activities, will be
maintained by the site owner for as long as it is necessary to serve the needs of long-term
management and maintenance.
5.1.2 Financial Assurances
The funding for the Springbrook Bank design, construction, monitoring, and a portion of the site
management during the establishment phase of the bank is secured through the 2003
Transportation Funding Package for the I -405 Corridor Program. The City is providing the land
in perpetuity and funding the trail design, trail construction, a portion of the site management of
the establishment phase and long-term management.
WSDOT, as the permit holder of the bank will be the responsible party for the financial
assurances during the establishment phase of the bank. As a state agency, WSDOT has secured
funds through the 2003 and 2005 Transportation Funding Packages. Future funds are secured
through annual legislative allocations to the department.
See Appendix B and D for the specific financial responsibilities of the each sponsor.
5.1.3 Site Access
The City will allow, or otherwise provide for, access to the site by BOC members or their agents
or designees, as reasonably necessary, for the purpose of inspection, compliance monitoring, and
remediation consistent with the terms and conditions of this MBI, throughout the period of bank
establishment, monitoring, and long-term management. Inspecting parties shall provide
reasonable notice, of not less than 24 hours, to WSDOT and the City, prior to inspection of
Springbrook Bank. Efforts shall be made to consolidate access requirements for BOC members
or their representatives, and not unreasonably disrupt or disturb mitigation activities on the
property.
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5.2 LONG-TERM MANAGEMENT GUIDELINES
Site management after the establishment phase will be conducted by the City to ensure that
functional benefits of the mitigation activities are not degraded. Springbrook Bank will be
managed to maximize fulfillment of mitigation bank goals and objectives by ensuring the long-
term protection of wetland and buffer areas. Long-term management of the site will focus on
maintaining native plant communities and wildlife habitat diversity. Site management activities
include, but are not limited to, weed control, trash removal, vandalism repair, and structure
and/or signage repair. The following guidelines are established to assist in management of the
site following the establishment phase:
• Deciduous scrub -shrub and forested areas will remain dominated by native woody
target species included in the planting plan or currently established on the site.
• Native woody vegetation appropriate for the site will dominate the reed canarygrass
treatment areas in Units A and B, and the wetland re-establishment areas in Units C
and E.
• Weed control activities at the site will meet requirements of all applicable State and
local requirements in force at the time.
• If hydrologic conditions change within the system providing hydrology to the
re-establishment area in Unit C, adjustments to the controls may be made. If excess
water threatens woody planting survival, then water from the grade -separation pump
station may be diverted to Springbrook Creek via existing infrastructure, or if
insufficient water is present, the height of the weir may be raised at the outflow of
the re-establishment area to retain more water at the site.
All structures and facilities within Springbrook Bank, including fences, the elevated boardwalk,
pump -station diversion pipe and structure, the Tukwila stormwater facility, and the stop -log
weir, shall be properly maintained in perpetuity or for as long as each is needed to accomplish
the goals of Springbrook Bank and achieve the requirements of the MBI.
The City will manage the site in perpetuity by fulfilling landowner obligations defined in the
Conservation Easement (see Appendix C) to maintain the ecological functions on the site.
The City can transfer its long-term responsibilities to a Long -Term Steward with approval of the
BOC. See Appendix B for detailed information.
5.3 FORCE MAJEURE
Management of Springbrook Bank includes administrative actions to be taken by the City and
WSDOT to ensure protection of the site. Any mitigation bank is vulnerable to natural events
such as wildfires, climatic instability, and disease that are beyond the control of the City and
WSDOT. The occurrence of such an event may necessitate changes to Springbrook Bank,
including revision of the MBI, to allow for activities that will offset and counteract the negative
environmental impacts of that event. Depending on the circumstances, however, it may be
appropriate to let nature take its course, particularly when acceptable environmental conditions
will be expected to eventually re-establish. The City and WSDOT, in coordination with the
BOC members, shall jointly determine what changes to Springbrook Bank will be in the best
interest of the bank and the aquatic environment. Any change to Springbrook Bank necessitated
by natural events beyond the control of the City and WSDOT shall be specified in a revised MBI
or other appropriate documents, which will require approval of the BOC members.
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6.0 GLOSSARY
Adaptive management: a systematic process for continually improving management
policies and practices by learning from the outcomes of actions. Related to compensatory
mitigation, it involves the applicant and the regulatory agencies discussing the problems
occurring on a compensation site and coming to agreement on possible solutions or
alternative approaches necessary to bring the site into compliance.
Aerial cover: is the percent of ground surface covered by vegetation of a particular
species (or suite of species) when viewed from above (Elzinga et al. 1998). Values for
aerial cover are typically obtained from point -line, point -frame, or line -intercept data.
Aerial cover does not include overlapping cover of separate plants, thus it does not
exceed 100%.
Class: a grouping based on shared characteristics in a classification scheme. In the
Cowardin et al. (1979) classification of wetlands a class is the third level in the
`taxonomy' of wetlands whereas in the hydrogeomorphic classification (Brinson 1993b)
it is the highest taxonomic unit.
Compensatory mitigation: the compensation stage of the mitigation sequence where
impacts to the functions and values of wetlands are replaced through creation, restoration,
or enhancement of other wetlands. Because regulatory requirements and policies tend to
focus on the compensation stage, the term "mitigation" is often used to refer to
compensation, which is just one part of the overall mitigation sequence.
Conservation easement: a restriction placed on a piece of property to protect the
resources (natural or man-made) associated with the parcel. The easement is either
voluntarily sold or donated by the landowner, and constitutes a legally binding agreement
that prohibits certain types of activities from taking place on the land.
Corridor: areas that contain relatively undisturbed habitat and/or vegetation that
maintain connections for wildlife throughout the landscape. Corridors usually represent
linear habitats with the range of environmental functions necessary to permit the
movement of animals between larger and more fully functioning habitats. Corridors can
include but are not limited to, annual or seasonal migration corridors that connect
wintering and breeding habitat, or intraseasonal corridors that connect foraging and
nesting habitat or breeding and dispersal habitat.
Depressional wetland: a class of wetlands in the hydrogeomorphic classification. These
are wetlands that occur in topographic depressions that exhibit closed contour interval(s)
on three sides and elevations that are lower than the surrounding landscape.
Ecological restoration: "Ecological restoration is the process of assisting the recovery of
an ecosystem that has been degraded, damaged, or destroyed." (From the Society for
Ecological Restoration website 2005 http://www.ser.org/)
Emergent wetland: a wetland class under the Cowardin classification that is dominated
by erect, rooted, herbaceous plants. Emergent wetlands include marshes and wet
meadows.
Enhancement: the manipulation of the physical, chemical, or biological characteristics
of a wetland site to heighten, intensify or improve specific function(s) or to change the
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growth stage or composition of the vegetation present. Enhancement is undertaken for
specified purposes such as water quality improvement, flood water retention or wildlife
habitat. Activities typically consist of planting vegetation, controlling non-native or
invasive species, modifying site elevations or the proportion of open water to influence
hydroperiods, or some combination of these. Enhancement provides a change in some
wetland functions and can lead to a decline in other wetland functions, but does not result
in a gain in wetland acres.
Establishment (creation): the manipulation of the physical, chemical, or biological
characteristics present to develop a wetland on an upland or deepwater site, where a
wetland did not previously exist. Activities typically involve excavation of upland soils to
elevations that will produce a wetland hydroperiod, create hydric soils, and support the
growth of hydrophytic plant species. Establishment provides a gain in wetland acres.
Establishment Phase: period begins at acceptance of planting and extends for the first
10 years or until all performance standards have been met.
Flood storage: the volume available for flood water from a river or stream to occupy
outside the channel itself. This storage can reduce peak flows in the channel and
desynchronize the movement of floodwaters downstream.
Functions: the physical, biological, chemical, and geologic interactions among different
components of the environment. See wetland functions.
Habitat: the environment occupied by individuals of particular species, population or
community.
Habitat functions: function provided by a wetland and driven by specific site attributes
related to it ability to provide habitat suitable for animals and plants in general or specific
groups or species.
Habitat structures: structures that increase the number and availability of habitat niches
at a site, which may include snags, large woody debris, and brush piles.
Hydric soils: a soil that formed under conditions of saturation, flooding, or ponding long
enough during the growing season to develop anaerobic conditions in the upper part.
Hydrogeomorphic (HGM) classification: a system used to classify wetlands based on
the position of the wetland in the landscape (geomorphic setting), the water source for the
wetland, and the flow and fluctuation of the water once in the wetland.
Hydrogeomorphic wetland class: the highest level in the Hydrogeomorphic
classification of wetlands. There are six basic hydrogeomorphic wetland classes
including depressional, tidal fringe, slope, riverine, lake fringe, and flat. See class.
Hydrologic functions: functions provided by a wetland related to its ability to provide
flood storage, reduce peak flows, and reduce downstream erosion. These functions are
driven by specific site attributes.
Hydrologic regime: see hydroperiod below.
Hydroperiod: the pattern of water level fluctuations in a wetland. Includes the depth,
frequency, duration, and timing of inundation or flooding. Patterns can be daily, monthly,
seasonal, annual or longer term.
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Hydrophytic vegetation: a plant species that is typically adapted to life in saturated soil
conditions.
Inundated: water covering land not usually submerged, usually from flooding.
Invasive species: defined by the National Invasive Species Council (NISC) as "(1) a
non-native (alien) to the ecosystem under consideration and (2) a species whose
introduction is likely to cause economic or environmental harm, or harm to human
health."
Jurisdictional wetland: a wetland that is regulated by the provisions of the law under the
jurisdiction of one or more federal, state, or local agencies. Not all areas of the landscape
that have the biological characteristics of wetlands are regulated or jurisdictional
wetlands.
Large woody debris (LWD): large pieces of downed wood such as logs, rootwads, and
limbs that are in or near a body of water. LWD provides habitat structure for fish and
other aquatic organisms.
Limiting factor: an environmental factor that limits the growth or activities of an
organism or that restricts the size of a population or its geographical range.
Long -Term Management Period: begins at the end of the establishment phase and
extends for perpetuity.
Microtopography: minor variations in the elevation of the ground surface.
Mitigation (or mitigation sequencing): a series of actions that requires addressing each
action, or step, in a particular order. This sequence of steps is used to reduce the severity
of negative impacts from activities that potentially affect wetlands. Mitigation involves
the following:
1) Avoiding the impact altogether by not taking a certain action or parts of an action;
2) Minimizing impacts by limiting the degree or magnitude of the action and its
implementation, by using appropriate technology, or by taking affirmative steps,
such as project redesign, relocation, or timing, to avoid or reduce impacts;
3) Rectifying the impact by repairing, rehabilitating, or restoring the affected
environment;
4) Reducing or eliminating the impact over time by preservation and maintenance
operations during the life of the action;
5) Compensating for the impact by replacing, enhancing, or providing substitute
resources or environments; and
6) Monitoring the required compensation and taking remedial action when necessary
(WAC 197.11.768). See compensatory mitigation.
Mitigation banking: has been defined as "wetland restoration, creation, enhancement,
and in exceptional circumstances, preservation undertaken expressly for the purpose of
compensating for unavoidable wetland losses in advance of development actions, when
such compensation cannot be achieved at the development site or would not be as
environmentally beneficial." 1995 Federal Guidance on Wetland Mitigation Banking
(U.S. Army Corps of Engineers 1995)
Mitigation credit: for the purposes of this Mitigation Bank Instrument, one mitigation
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credit is valued as one unit of mitigation "currency" required to compensate for one acre
of Category II wetland as defined by the Washington State Department of Ecology
Rating System (Hruby 2004).
Monitoring: a systematic evaluation of the site by qualified personnel to determine the
degree to which the site meets its performance standards, and to determine modifications
in management and maintenance of the site needed to achieve performance standards.
Formal: quantitative sampling techniques will be used to assess if the site is
achieving specific performance standards, which may be tied to the release of
mitigation credits.
Informal: qualitative visual inspection of the site to identify any issues and
necessary adaptive management actions.
Performance standards: quantifiable standards capable of measuring the degree of
success of a site compared to established goals and objectives.
Planting hummock: a raised area to provide topographic variation and facilitate tree
establishment in existing wetlands.
Perpetuity: forever, eternity.
Protection Setback (Buffer): vegetated areas adjacent to wetlands, or other aquatic
resources, that can reduce impacts from adjacent land uses through various physical,
chemical, and/or biological processes.
Reach: a segment of river or stream and associated riparian area defined by geomorphic
features with similar environment and aquatic habitat.
Re-establishment: the manipulation of the physical, chemical, or biological
characteristics of a site with the goal of returning natural or historic functions to a former
wetland. Activities could include removing fill material, plugging ditches or breaking
drain tiles. Re-establishment provides a gain in wetland acres and functions. Compare to
rehabilitation. See also restoration and establishment.
Rehabilitation: the manipulation of the physical, chemical, or biological characteristics
of a site with the goal of repairing natural or historic functions and processes of a
degraded wetland. Activities could involve breaching a dike to reconnect wetlands to a
floodplain, restoring tidal influence to a wetland, or breaking drain tiles and plugging
drainage ditches. Rehabilitation provides a gain in wetland function but does not provide
a gain in wetland acres. Compare to establishment (creation), re-establishment and
enhancement. See also restoration.
Restoration: the manipulation of the physical, chemical, or biological characteristics of a
site with the goal of returning natural or historic functions to a former or degraded
wetland. For the purpose of tracking net gains in wetland acres, restoration is divided into
re-establishment and rehabilitation.
Riparian: the strip of land adjacent to a body of water that is transitional between the
aquatic system and the upland. Some riparian areas contain wetlands.
Riverine wetland: a class of wetlands in the hydrogeomorphic classification. Wetlands
that occur in floodplains and riparian corridors in association with stream or river
channels where there is frequent overbank flooding.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Service area: the geographic area in which the mitigation credits generated at a
mitigation bank site may be used to compensate for unavoidable wetland impacts.
Site management: activities undertaken at the site to address management needs, may
include: vandalism, weed control, replanting, maintaining structures, etc...
Stormwater: the water coming from rain or snow that runs off surfaces such as rooftops,
paved streets, highways, and parking lots. It can also come from hard grassy surfaces like
lawns, play fields, and from graveled roads and parking lots.
Sub -basin: a smaller drainage basin that is part of a larger drainage basin or watershed.
For example, the watershed of a large river may be composed of several sub -basins, one
for each of the river's tributaries.
Surface water: water present above the substrate or soil surface.
Unavoidable impact: impacts to wetlands or other aquatic resources that have gone
through the appropriate steps in the mitigation sequencing process. See mitigation.
Under -planting: Installation of plants under a canopy of existing woody vegetation.
Upland: any area that does not qualify as wetland because the associated hydrologic
regime in not sufficiently wet to elicit development of vegetation, soils, and/or hydrologic
characteristics associated with wetlands.
Water quality functions: functions provided by a wetland and driven by specific site
attributes related to its ability to improve water quality including: removing sediment,
nutrients, and heavy metals and toxic organic compounds.
Water Resource Inventory Area (WRIA): geographic area usually corresponding to
major watersheds. Washington State is divided into 62 WRIAs for water management
purposes.
Watershed: a geographic area of land bounded by topographic high points in which
water drains to a common destination.
Wetland: has been defined as "those areas that are inundated or saturated by surface or
ground water at a frequency and duration sufficient to support, and that under normal
circumstances do support, a prevalence of vegetation typically adapted for life in
saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar
areas." Washington State Wetlands Delineation Manual (Ecology 1997)
Wetland functions: the physical, biological, chemical, and geologic interactions among
different components of the environment that occur within a wetland. Wetlands perform
many valuable functions and these can be grouped into three categories (1) functions that
improve water quality, (2) functions that change the water regime in a watershed such as
flood storage, and (3) functions that provide habitat for plants and animals.
Wetland hydrology: the sum total of wetness characteristics in areas that are inundated
or have saturated soils for a sufficient duration to support hydrophytic vegetation.
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7.0 REFERENCES
Antieau, Clayton J. 1998. Biology and Management of Reed Canarygrass, and
Implications for Ecological Restoration. Washington State Department of
Transportation, Seattle, WA. http://www.semw.org/docs/RCG.rtf
Antieau, Clayton J. 2005. Personal Communication. Seattle Public Utilities. [October 6,
2005]
R.W. Beck, 1996. East Side Green River Watershed Project Plan and Environmental
Impact Statement. Prepared for the City of Renton Department of
Planning/Building/Public Works.
Brinson, M.M. 1993. A Hydrogeomorphic Classification for Wetlands. Tehnical Report
WRP-DE-4. U.S. Army Corps of Engineers Waterways Experiment Station.
Vicksburg, MS
Buis, Susan. 2005. Personal Communication. Washington State Department of
Transportation. [September 29, 2005]
Celedonia, M. 2002. Benchmarks for Stand Development of Forested and Scrub -shrub
Plant Communities at Wetland Mitigation Sites in the Lowlands of Western
Washington. Washington State Department of Transportation, Olympia, WA.
http://www.wsdot.wa. gov/eesc/design/roadside/pdf/miti gationbenchmark.pdf
Cowardin, L.M., 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
Publication FWS/OBS-79/31. Washington D.C.
Elzinga, C. L., D. W. Salzer, and J. W. Willoughby. 1998. Measuring and Monitoring
Plant Populations. Bureau of Land Management Technical Reference 1730-1,
BLM/RS/ST-98/005+1730. National Business Center, Denver, CO.
Environmental Laboratory. 1987. Corps of Engineers Wetland Delineation Manual.
Technical Report Y-87-1, U.S. Army Corps of Engineers Waterways Experiment
Station. Vicksburg, MS.
Environmental Protection Agency (EPA). 2002. Draft: Level III and IV Ecoregions of the
Northwestern United States. flp:Hftp.eva.gov/wed/ecoregions/or wa id/pnw mM.pdf
Hart Crowser. 2005a. Geotechnical Baseline Report 1-405 Springbrook Creek Wetlands
and Habitat Mitigation Project. Seattle, WA. [October 4, 2005]
Hart Crowser. 2005b. Geotechnical Baseline Recommendations I-405 Springbrook Creek
Wetland and Habitat Mitigation Bank Project Trail Renton, WA. Seattle, WA.
[October 26, 2005]
Harza. 1995. Final Report — Comprehensive Fisheries Assessment of the Mill Creek,
Garrison Creek and Springbrook Creek System. Prepared for the City of Kent,
Washington.
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Hoover, Monica. 2005. Personal Communication. Natural Resources Conservation
Service. [September 29, 2005]
HRA Cultural Resources. 2005. I-405, Springbrook Creek Habitat and Wetland
Mitigation Bank Project, Cultural Resources Discipline Report. Seattle, WA.
[November 2005]
Hruby, T. 2004. Washington State Wetland Rating System for Western Washington —
Revised. Washington State Department of Ecology Publication # 04-06-025.
Hruby, T., T. Granger, K. Brunner, S. Cooke, K. Dublancia, R. Gersib, L. Reinelt, K.
Richter, D. Sheldon, E. Teachout, A. Wald, and F. Weinmann. 1999. Methods for
Assessing Wetland Functions Volume 1: Riverine and Depressional Wetlands in the
Lowlands of Western Washington, Part 1: Assessment Methods. Washington State
Department of Ecology Publication #99-115. Olympia, WA.
Hruby, T., T. Granger, and E. Teachout. 1999. Methods for Assessing Wetland Functions.
Volume 1: Riverine and Depressional Wetlands in the Lowlands of Western
Washington. Pert 2: Procedures for Collecting Data. Washington State Department
of Ecology Publication #99-116. Olympia, WA.
Kercher, Suzanne M., Quentin J. Carpenter, and Joy B. Zedler. 2004. Interrelationships
of Hydrologic Disturbance, Reed Canary Grass (Phalaris arundinacea L), and
Native Plants in Wisconsin Wet Meadows. Natural Areas Journal 24(4): 316-325.
hqp://www.botaiiy.wisc.edu/zedler/images/KercherNAJ.pd
Kerwin, John and Nelson, Tom S. (Eds.). 2000. Habitat Limiting Factors and
Reconnaissance Assessment Report, Green/Duwamish and Central Puget Sound
Watersheds (WRIA 9 Vashon Island). Washington Conservation Commission and
King County Department of Natural Resources. http://salmon.scc.wa.gov
King County. 2005. Noxious Weed List. w,,vw.dnr.metrokc.gov/wlr/lands/weeds/laws.htm
King County. 1998. King County, Washington Surface Water Design Manual. King
County Department of Natural Resources, Seattle, WA.
Puget Sound River History Project. 2005. http://riverhistorv.ess.washington.edu/
Malcom, Roderick W.R. 1998. The Contribution of Reed -Canary Grass Dominated Low
Gradient Streams to Juvenile Salmon Overwintering Habitat. Muckleshoot Indian
Tribe Fisheries Department. Presented at Puget Sound Research Conference, March
1998, Seattle, WA.
http://www.psat.wa.gov/Publications/98 proceedings/pdfs/la abstracts.pdf
Maurer, Debbie A., Roberto Lindig-Cisneros, Katherine J. Werner, Suzanne Kercher,
Rebecca Miller, and Joy B. Zedler. 2003. The Replacement of Wetland Vegetation by
Reed Canarygrass (Phalaris arundinacea). Ecological Restoration, 21(2): 116-119.
http://ipaw.org/symposium/Maurer et al.pdf
Miller, Rebecca C. and Joy B. Zedder. 2002. Responses of Native and Invasive Wetland
Plants to Hydroperiod and Water Level Depth. University of Wisconsin, Madison,
Wl. http://www.botany.wisc.edu/zedler/imaizes/MillerP1.Ecol.pdf
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Natural Resources Conservation Service (MRCS). 2001. Hydric Soils List. King County
Area, Washington. U.S. Department of Agriculture [10/30/2001]
hq://www.wa.nres.usda.gov/technical/soils/county hydric lists.html
Reinhardt, Carrie and Susan M. Galatowitsch. 2004. Best Management Practices for the
Invasive Phalaris arundinacea L. (reed canary grass) in Wetland Restorations.
Minnesota Department of Transportation, St. Paul, MN. [Final Report, May 2004]
http://www.fws. gov/shorebirdplan/UsShorebird/downloads/ReedCanMGrassReport
2004.pdf
Renton, City of. 2004. Comprehensive Plan. Renton, WA.
hitp://www.ci.renton.wa.us/ednsp/compplan.htm
Renton, City of. 2005. Critical Areas Ordinance. Ordinance number 5137. Renton, WA.
http://rentonnet.or intemetapps/files/ednsp/1177pdf
Renton, City of. June 1992. Parks, Recreation, and Open Space Plan. Renton, WA.
Renton, City of. June 1992. Trails Master Plan. Renton, WA.
Seattle Audubon. 2005. Places to see Great Blue Herons in the Puget Sound Region.
hqp://www.seattleaudubon.org/birding.cftn?id=498
n?id=498
Smith, D.R., A. Ammann, C. Bartoldus, and M.M. Brinson. 1995. An Approach for
Assessing Wetland Functions Using Hydrogeomorphic Classification, Reference
Wetlands, and Functional Indices. Technical Report WRP-DE-9. US Army
Waterways Experiment Station. Vicksburg, MS.
hqp://el.erdc.usace.army.mil/wetlands/pdfs/wipde9.pd
Soll, Jonathan. Controlling Himalayan Blackberry in the Pacific Northwest. The Nature
Conservancy. hLtp:Htncweeds.ucdavis.edu/moredocs/rubarmOl.pdf
Stehman, Stephen V and Daniel W. Salzer. 2000. Estimating Density from Surveys
Employing Unequal -Area Belt Transects. WETLANDS. Vol. 20. No. 3. pp. 512-519.
The Society of Wetland Scientists. Ann Arbor, MI.
Snyder, Dale E., Phillip S. Gale, Russell F. Pringle. 1973. Soil Survey of the King County
Area, Washington. US Department of Agriculture, Soil Conservation Service,
Washington, D.C.
Tu, Mandy. 2004. Reed Canarygrass: Control and Management in the Pacific Northwest.
The Nature Conservancy, Portland, OR.
hqp://tncweeds.ucdavis.edu/moredocs/phaaru0 l .pdf
U.S. Army Corps of Engineers et al. 1995. Federal Guidance for the Establishment, Use,
and Operation of Mitigation Banks. Federal Register Vol. 60, No.228, p. 58605-
58614. [November 28, 1995]
Washington, State of. 2001. Washington State Draft Rule on Mitigation Banking. WAC
173-700. http://www.ecy.wa.gov/laws-rules/wacl73700/draftruteeasyread.pdf
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Washington State Department of Ecology (Ecology). 1997. Washington State Wetlands
Identification and Delineation Manual. Washington State Department of Ecology.
Publication #96-94. http://www.ecy.wa.gov/biblio/9694.html
Washington State Department of Ecology. 2005. Wetlands in Washington State — Volume
2: Guidance for Protecting and Managing Wetlands. Washington State Department
of Ecology. Publication #05-06-008. Olympia, WA.
http://www.ecy.wa.gov/progrrams/sea/bas wetlands/volume2final.html
Washington State Department of Transportation (WSDOT). 1994. Washington State
Department of Transportation Wetland Compensation Bank Program Memorandum
of Agreement. Signatories include U.S. Army Corps of Engineers, U.S.
Environmental Protection Agency, U.S. Fish and Wildlife Service, National Marine
Fisheries Service, Federal Highway Administration, Washington State Department of
Ecology, Washington State Department of Fish and Wildlife, and Washington State
Department of Transportation.
http://www.wsdot.wa. gov/environment/biology/docs/WetlandMOAFinaI 1994.pdf
Washington State Department of Transportation (WSDOT). 2005a. Springbrook Creek
Mitigation Site Wetland Delineation Report. Washington State Department of
Transportation, I-405 Office, Bellevue, WA. [May 2005]
Washington State Department of Transportation (WSDOT). 2005b. Springbrook Wetland
and Habitat Mitigation Bank. Springbrook. Creek Hydrological Analysis. Washington
State Department of Transportation, I-405 Office, Bellevue, WA. [August 2005]
Washington State Department of Transportation (WSDOT). 2005c. Springbrook Wetland
and Habitat Mitigation Bank: Unit C Water Balance Memorandum. Washington
State Department of Transportation, I-405 Office, Bellevue, WA. [August 2005]
Washington State Department of Transportation (WSDOT). 2005d. Black River Pump
Station Fish Passage Biological Feasibility. Washington State Department of
Transportation, I-405 Office, Bellevue, WA. [October 2005]
Washington State Department of Transportation (WSDOT). 2006. Springbrook Wetland
and Habitat Mitigation Bank: Biological Assessment. Washington State Department
of Transportation,l-405 Office, Bellevue, WA. [January 2006]
Washington State Noxious Weed Control Board. 2005. Noxious Weed List.
www.nwcb.wa.gov/INDEX.htm
Watershed Water Resource Inventory Area 9 (WRIA 9) Steering Committee. 2005.
Salmon Habitat Plan — Making Our Watershed Fit for a King. Prepared for the
WRIA 9 Forum. hllp://dnr.metrokc.2ov/Wrias/9/HabitatPlan.htm
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Appendix A
Monitoring Plan—
Springbrook Creek Wetland and Habitat Mitigation Bank
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
1.0 INTRODUCTION
This monitoring plan describes the framework and methods that Washington Department of
Transportation (WSDOT) and the City of Renton (City) will use to monitor the Springbrook Creek
Wetland and Habitat Mitigation Bank (Springbrook Bank). Monitoring results will be used to
document how Springbrook Bank is performing in relation to the project objectives and performance
standards documented in the Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
(MBI). Documented monitoring results will be used to establish when mitigation credits from
Springbrook Bank are eligible for release.
2.0 WSDOT WETLAND MITIGATION MONITORING PROGRAM
WSDOT's Wetland Mitigation Monitoring Program (Monitoring Program) staff will conduct the
site monitoring at the Springbrook Bank during the establishment phase (Year 0 to Year 10).
The Monitoring Program conducts compliance monitoring for the majority of WSDOT's
compensatory wetland mitigation projects statewide. Compliance monitoring provides a means
for tracking the development of WSDOT mitigation projects over time, and for determining
compliance with permits issued by federal, state, local, or tribal jurisdictions. The monitoring
data also provide an important internal feedback role in mitigation site management and
maintenance serving as an essential link in the internal adaptive management process, which
increases the overall success of the mitigation sites.
The City will conduct periodic site visits at the Springbrook Bank during the long-term
management and maintenance period to assess the need and scope of any additional site
management activities.
2.1 Monitoring Protocols
WSDOT's Monitoring Program uses both formal and informal methods. Formal monitoring
may include qualitative monitoring and/or quantitative monitoring addressing the performance
standards in a given year. Informal monitoring will usually be conducted during years for which
there are no performance standards, intending to provide a general idea of how the site is
performing, and may only include qualitative monitoring. Informal monitoring may
quantitatively address some performance standards, but may be less statistically rigorous than
formal monitoring. Results (compliance with performance standards) of both formal and
informal monitoring will be summarized in monitoring reports and submitted to BOC members.
During some interim years that neither formal nor informal monitoring is scheduled, internal site
inspections will take place with no external reporting. The results of internal site inspections will
be used to guide site management activities at Springbrook Bank.
The Monitoring Program uses quantitative data collection techniques based on standard
ecological and biostatistical methods. The configuration, placement, and number of sample units
(e.g., belt transects, plots, lines, point -lines, point frames) required to address site -specific
performance objectives will be based on characteristics observed in the vegetative community
and patterns of plant distribution. Sample size analysis will be used to ensure data from an
adequate number of sample units has been obtained to meet the sampling objectives. Monitoring
reports will include a description of the methods and sampling designs used to monitor
Springbrook Bank.
AMA Spdngbrook_Monito irg Plan 041906.doc
Appendix A May 2006
Monitoring Plan Page A-1
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Further information on WSDOT monitoring methods is available at:
http://www.wsdot.wa.gov/environment/biology/docs/MethodsWhitePaperO52004.pdf
2.2 Submission of Annual Reports
WSDOT will prepare and submit annual monitoring reports to BOC members, on behalf of itself
and the City, during the establishment phase of the Bank. The reports will be submitted by
March 31 after each monitoring year for which a report is required. These reports will document
the progress that has been made towards achieving the performance standards specified in the
MBI. Reports will also include descriptions of adaptive management actions that have been
taken to facilitate achievement of performance standards that are not being met.
3.0 GOALS, OBJECTIVES, AND PERFORMANCE STANDARDS
3.1 Goal
Springbrook Bank will increase wetland area, improve hydrologic functions, water quality
functions, habitat functions, fish refuge/rearing habitat, and promote environmental education
3.2 Objectives
Springbrook Bank will re-establish 17.81 acres of wetland; rehabilitate 52.92 acres of wetland,
enhance 33.61 acres of wetland, enhance 6.88 acres of riparian area, and 7.80 acres of uplands;
and result in significant improvements for fish and wildlife habitat, water quality, and other
stream and wetland functions in the Black River Basin. The mitigation design includes removal
of fill from areas of historic wetlands, re -connecting Springbrook Creek to its floodplain, and
improving functions in existing wetlands.
3.3. Performance Standards
Performance standards outlined in the MBI (Section 3.3) are intended to measure the success of
Springbrook Bank in meeting the overall project goals and objectives. Performance standards
establish specific parameters that the site must meet in order to determine that the goals and
objectives have been met.
4.0 MONITORING SCHEDULE
A combination of formal and informal monitoring of Springbrook Bank will occur during the
establishment phase of the Bank (Tables A-1 and A-2). Site visits will occur periodically after
the 10-year monitoring period to document changes in the site over time and to provide
information to WSDOT and the City (who is the lead entity for long-term site management).
Formal monitoring will occur once per specified year between June and September, while
informal monitoring may occur periodically throughout the year. More frequent monitoring
may be warranted because of specific site conditions or site -specific goals. For example, more
frequent monitoring may be necessary to track the cover of invasive weeds or report results from
management treatments that are needed. The Springbrook Bank will be monitored according to
the schedules listed below.
App A SpringbrookMonitonng Plan_041906.doc
Appendix A May 2006
Monitoring Plan Page A-2
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Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Table A-1
Formal Monitoring Schedule
Monitorina Yaart Frenuenev
Year 1
Annual Site Visit
Year 3
Annual Site Visit
Year 5
Annual Site Visit
Year 7
Annual Site Visit
Year 10
Annual Site Visit
Additional formal monitoring may be needed to
measure site attributes identified in performance
standards (see MBI Section 3.3).
Table A-2
Informal Monitoring Schedule
Monitorina Year Frenuencv
Year 1
Quarterly Site Visits
Year 2
Quarterly Site Visits
Year 3
Quarterly Site Visits
Year 4
Quarterly Site Visits
Year 5
Quarterly Site Visits
Year 6
Annual Site Visit
Year 7
Annual Site Visit
Year 8
Annual Site Visit
Year 9
Annual Site Visit
Year 10
Annual Site Visit
5.0 MONITORING TASKS AND METHODS
The monitoring tasks are summarized in Table A-3. The specific methods to be used are
discussed in more detail in the text that follows.
Table A-3 MonitorinLy Tasks by Year
Monitoring
Monitoring Tasks
Expected Site Visits
Year
(with Corresponding Performance Standard)
Year 0
Submittal of As -Built drawings depicting the grading, planting, habitat structure
Several times during
placement, and water routing structures will be submitted to BOC signatories at
site construction.
the completion of construction/planting (A/B-1, C-1, D-1, and E-1).
Once upon completion
. Establish conservation easement and submit (may occur before Year 0).
of site
construction/plant
installation.
Year 1
Estimate density of living native woody stems in wetland planting areas (A/B-3A,
Quarterly informal site
C-3A, D-2A, and E3-A).
visits. Monitoring
. Estimate density of living native woody stems in upland and riparian upland
activities will occur in
planting areas (A/B-3B, C-3B and E-3B).
appropriate seasons
. Estimate density of conifers in under -planted Forest Wetland Enhancement
during quarterly site
Areas (C-3C, D-213, and E-3C).
visits.
Identify any populations of Japanese knotweed, purple loosestrife, English ivy,
and other Class A and B noxious weed and remove (A/B-9, C-8, D-3, and E-8).
. Identify and count habitat structures in all units to confirm installed per as -built
drawings (A/B-10, C-19, D4, and E-9).
. Conduct multiple early growing season monitoring visits to assess if wetland
hydrology is present in the wetland re-establishment areas for at least 10% of the
growing season in Units A, B, C, and E. (A/B-2A, C-2A, and E-2A).
. Conduct informal monitoring visits in quarters other than that of formal monitoring
to assess site conditions and identify any issues or problems.
. GPS planting hummocks to be able to locate in future.
. Take representative photos of each site to document progress.
. Submit formal monitoring report and credit ledger.
Year 2
Identify any populations of Japanese knotweed, purple loosestrife, English ivy,
Quarterly site visits
and other Class A and B noxious weed and remove (A/B-9, C-8, D-3, and E-8).
. Conduct multiple early growing season monitoring visits to assess if wetland
hydrology is present in the wetland re-establishment areas for at least 10% of the
growing season in Units A, B, C, and E. (A/B-2A, C-2A, and E-2A).
. Monitor for any standards not achieved in Year 1 to assess for credit release.
App A Springbrook_Monitoring Plan_041906.doc
Appendix A May 2006
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FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Monitoring
Monitoring Tasks
Expected Site Visits
Year
(with Corresponding Performance Standard)
. Conduct quarterly informal site visits to assess site conditions and identify any
issues or problems.
. Submit monitoring report and credit ledger.
Year 3
. Conduct multiple early growing season monitoring visits to assess if wetland
Quarterly site visits.
hydrology is present in the wetland re-establishment areas for at least 10% of the
Monitoring activities
growing season in Units A, B, C, and E. (A/B-2A, C-2A, and E-2A).
will occur in
. Document the extent of over -bank flooding from Springbrook Creek during late
appropriate seasons
winter and/or early spring storm -events in Units A and B (A/B-2A).
during quarterly site
. Determine the extent of permanent un-vegetated open water in Units A, B, and E
visits.
during summer monitoring visit (A/13-213 and E-26).
. Determine if inundation is still evident in the northern portion of Unit D on June
15th (D-1 B).
. Estimate density of living native woody stems in wetland planting areas (A/B-4,
C4A, and E4).
. Estimate the density of living conifers per acre in the Wetland Enhancement
Type I areas in Unit C (C413).
. Identify any populations of Japanese knotweed, purple loosestrife, English ivy,
and other Class A and B noxious weed and remove (A/B-9, C-8, D-3, and E-8).
. Take representative photos of each site to document progress.
. Conduct informal monitoring visits in quarters other than that of formal monitoring
to assess site conditions and identify any issues or problems.
. Submit formal monitoring report and credit ledger.
Year 4
Identify any populations of Japanese knotweed, purple Ioosestrife, English ivy,
Quarterly site visits
and other Class A and B noxious weed and remove (A/6-9, C-8, D-3, and E-8).
. Monitor for any standards not achieved in prior years to assess for credit release.
. Conduct quarterly informal site visits to assess site conditions and identify any
issues or problems.
. Submit monitoring report and credit ledger.
Year 5
Conduct wetland delineations in Wetland Re -Establishment areas in Units A, B,
Quarterly site visits.
C, and E (A/B-2C, C-213, and E-26).
Monitoring activities
. Conduct wetland delineation of existing wetlands in Units A and B to document
will occur in
that berm breaches have not adversely affected wetlands in these units (A/B-2C).
appropriate seasons
. Determine the extent of permanent un-vegetated open water in Units A, B, and E
during quarterly site
during summer monitoring visit (A/B-2B and E-213).
visits.
Estimate aerial cover of native woody vegetation in Wetland Tree/Shrub planting
areas in Units A, B, C, and E (A/B-5A, C-5A, and E-5A).
. Determine if three native woody species are each providing a minimum of 5%
aerial cover in the wetland planting areas in Units A, B, C, and E (A/13-56, C-513,
and E-5B).
. Determine if planting hummocks have a minimum of 1 living tree per hummock in
Units A and B (A/B-8).
. Estimate aerial cover of native woody vegetation in the Upland and Riparian
Upland Planting areas in Units A, B, C and E (A/B-5C, C-5C, and E-5C).
. Determine if three native woody species are providing at least 3% cover each in
the Upland and Riparian Upland planting areas in Units A, B, C, and E (A/B-5D,
C-5D, and E-5D).
. Estimate density of conifers in under -planted Forest Wetland Enhancement
Areas (C-3C, D-213, and E-3C).
. Estimate aerial cover of Himalayan blackberry in uplands at Units A, B, C, and E,
over entire site at Unit D, and in the re-establishment area in Units C and E.
Verify that Himalayan blackberry does not cover more than 20% of the uplands at
App A Spnngbrook_Monitonng Plan_041906.doc
Appendix A May 2006
Monitoring Plan Page A-4
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Monitoring
Monitoring Tasks
Expected Site Visits
Year
(with Corresponding Performance Standard)
any site or more than 10% of the re-establishment areas (A/B-9, C-8, D-3, and E-
8).
. Identify any populations of Japanese knotweed, purple loosestrife, English ivy,
and other Class A and B noxious weed and remove (A/B-9, C-8, D-3, and E-8).
. Take representative photos of each site to document progress.
. Submit formal monitoring report and credit ledger.
Year 6
Identify any populations of Japanese knotweed, purple loosestrife, English ivy,
Annual site visit
and other Class A and B noxious weed and remove (A/B-9, C-8, D-3, and E-8).
. Monitor for any standards not achieved in prior years to assess for credit release.
. Submit report (if prior year standards monitored for credit release) and credit
ledger.
Year 7
Estimate aerial cover of native woody vegetation in Wetland Tree/Shrub planting
Annual site visit
areas in Units A, B, C, and E (A/B-6, C-6A, and E-6).
. Estimate density of living native conifers in Wetland Enhancement Type I areas in
Unit C (C-66).
. Determine if inundation is still evident in the northern portion of Unit D on June
15th (D-1 B).
. Identify any populations of Japanese knotweed, purple loosestrife, English ivy,
and other Class A and B noxious weed and remove (A/B-9, C-8, D-3, and E-8).
. Monitor for any standards not achieved in prior years to assess for credit release.
. Take representative photos of each site to document progress.
. Submit formal monitoring report and credit ledger.
Year 8
Identify any populations of Japanese knotweed, purple loosestrife, English ivy,
Annual site visit
and other Class A and B noxious weed and remove (A/B-9, C-8, D-3, and E-8).
. Monitor for any standards not achieved in prior years to assess for credit release.
. Submit report (if prior year standards monitored for credit release) and credit
ledger.
Year 9
Identify any populations of Japanese knotweed, purple loosestrife, English ivy,
Annual site visit
and other Class A and B noxious weed and remove (A/B-9, C-8, D-3, and E-8).
. Monitor for any standards not achieved in prior years to assess for credit release.
. Submit report (if prior year standards monitored for credit release) and credit
ledger.
Year 10
Estimate the aerial cover of native woody vegetation in Wetland Tree/Shrub
Annual site visit
planting areas in Units A, B, C, and E (A/B-7A, C-7A, and E-7A).
. Determine if two native woody species are each providing a minimum of 10%
aerial cover in the Wetland Tree/Shrub planting areas in Units A, B, C, and E
(A/B-7B, C-713, and E-76).
. Estimate the aerial cover of native woody vegetation in the Upland and Riparian
Upland planting areas in Units A, B, C, and E (A/B-7C, C-7C, and E-7C).
. Determine if two native woody species are each providing a minimum of 7% in
the Upland and Riparian Upland planting areas in Units A, B, C, and E. (A/B-7D,
C-71D, and E-71D).
. Identify any populations of Japanese knotweed, purple loosestrife, English ivy,
and other Class A and B noxious weed and remove (A/B-9, C-8, D-3, and E-8).
. Determine if planting hummocks have a minimum of 1 living tree per hummock in
Units A and B (A/B-8).
. Estimate aerial cover of Himalayan blackberry in uplands Units A, B, C, and E,
over entire site at Unit D, and in the re-establishment area in Units C and E.
Verify that Himalayan blackberry does not cover more than 20% of the uplands at
any site or more than 10% of the re-establishment areas (A/B-9, C-8, D-3, and E-
8.
App A Springbrook_Monitoring Plan_041906.doc
Appendix A May 2006
Monitoring Plan Page A-5
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
Monitoring
Year
Monitoring Tasks
(with Corresponding Performance Standard)
Expected Site Visits
. Conduct wetland delineations in Wetland Re -Establishment areas in Units A, B,
C, and E (A/B-2C, C-26, and E-213).
. Conduct wetland delineation of existing wetlands in Units A and B to document
that berm breaches have not adversely affected wetlands in these units (A/B-2C).
. Determine the extent of permanent un-vegetated open water in Units A, B, and E
during summer monitoring visit (A113-26 and E-2B).
. Take representative photos of each site to document progress.
. Submit formal monitoring report and credit ledger.
After Year 10
Monitor for any standards not achieved in prior years to assess for credit release.
Periodic site visits
. Submit report if prior standards monitored for credit release and credit led er.
5.1 Conduct formal monitoring (Years 1, 3, 5, 7, and 10).
Formal monitoring addresses the site's fulfillment of project goals, objectives, and performance
standards. It may include qualitative and/or quantitative monitoring that is summarized in a
monitoring report and submitted to the BOC. Quantitative formal monitoring will attempt to
provide an estimate with a confidence level of 80 percent and confidence interval of 20 percent
to address standards requiring biostatistical sampling methods to address. Formal monitoring
will be conducted during Years 1, 3, 5, 7, and 10,.which have performance standards to address.
Formal monitoring may also be conducted in additional years not listed to assess performance
standards not met in designated years.
5.2 Conduct informal monitoring (Years 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10).
In contrast to formal monitoring, informal monitoring is intended to provide a general overview
of site progress versus a direct assessment of performance standards. A qualitative visual
inspection of the mitigation area will be conducted to identify concerns associated with meeting
project goals and objectives. Informal monitoring may also quantitatively addresses some
performance standards of coming years to assess progress toward meeting future goals, but may
be less statistically rigorous than formal monitoring. Informal monitoring will be the only
monitoring method during years 2, 4, 6, 8, and 9 for which there are no performance standards,
although qualitative methods will also be employed during some informal site visits in years of
formal monitoring. Informal monitoring will also identify any noxious weed of other invasive
species issues that need to be addressed at the site.
5.3 Complete monitoring report and submit to the BOC (Years 1, 2, 3, 4, 5, 7, and 10).
Monitoring reports will provide a description of site conditions observed during the past year.
Reports will include results from formal and/or informal monitoring visits, along with an
assessment of site conditions as they relate to the performance standards outlined in the MBI.
Results of monitoring will lead to recommendations for any management and/or contingency
actions that may be necessary to ensure that the objectives and goals of the Springbrook Bank are
met. The monitoring report will also describe adaptive management activities that may be
necessary or have been implemented to meet current and future performance standards.
Monitoring reports will be submitted to the BOC in Years 1, 2, 3, 4, 5, 7, and 10, additional
App A Spnngbrook_Mondonng Plan_041906.doc
Appendix A May 2006
Monitoring Plan Page A-6
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
reports may be submitted in years not specified if unmet performance standards from prior years
have been monitored.
5.4 Verify habitat structures still exist per as -built drawings (Year 1)
(Performance Standards A/B-11, C-10, D-5, and E-10)
Locate all habitat structures shown in as -built drawings in Units A, B, C, D, and E in Year I to
verify they were installed per plan and remain on -site.
5.5 Determine density of native woody stems within Wetland Tree/Shrub planting areas
in Units A, B, C, D, and E (Years 1 and 3)
(Performance Standards A/11-3A, A/11 4, C-3A, C4A, D-2A, E-3A, and E4).
The density of living native woody stems per acre in the Wetland Tree/Shrub planting areas will
be determined in Years 1 and 3 using randomly placed un-equal area belt transects as described
by Stehman and Salzer (2000) or other methods determined appropriate for the site. This
estimate will include any natural recruitment of native species in addition to planted materials.
Transects will be randomly placed along a perpendicular baseline, with the long axis of each
transect running parallel to the strongest environmental gradient.
Sampling objectives for this type of monitoring include two components related to the precision
of the estimate:
• The confidence level. How confident are you that your confidence interval will include the
true value?
• The confidence interval width. How wide is the range you are willing to accept around your
estimated value?
The sampling objective is to be 80 percent confident that the true number of woody stems per
acre in wetland planting areas at Springbrook Bank is within 20 percent of the estimated density.
The estimate generated via sampling will be compared to the relevant performance standards to
determine if the standards have been met and if the associated credits are eligible for release.
5.6 Estimate density of native -,coody stems within the Upland and Riparian Upland
planting areas in Unit A, B, C, and E (Year 1)
(Performance Standards A/13-311, C-311, and E-3B).
The density of living native woody stems per acre in the Upland and Riparian Upland planting
areas will be determined in Year 1 using randomly placed un-equal area belt transects as
described by Stehman and Salzer (2000) or other methods determined appropriate for the site.
This estimate will include any natural recruitment of native species in addition to planted
vegetation. Transects will be randomly placed along a perpendicular baseline, with the long axis
of each transect running parallel to the strongest environmental gradient. Results will be
compared to the relevant performance standards to assess if the standards are being met and if
the associated credits are eligible for release.
App A Spnngbrook_Monitonng Plan_041906.doc
Appendix A May 2006
Monitoring Plan Page A-7
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
method as described in Elzinga et al. (1998) or other statistically appropriate method. Data will
be collected by species. Transects will be placed perpendicular to the strongest environmental
gradient. Sampling objectives are to be 80 percent confident that the estimate is within 20
percent of the true value. Estimates derived from sampling will be compared to the relevant
performance standard to assess if the standards are being met and if the associated credits are
eligible for release.
5.11 Determine if three native woody species have 5% or greater cover in the Wetland
Tree/Shrub planting areas in Units A, B, C, and E (Year 5)
(Performance Standards A/B-5B, C-511, C-713, and E-513)
Using the aerial cover by species data collected in Year 5 for the Wetland Tree/Shrub planting
areas in Units A, B, C, and E, determine if three native woody species each provide five percent
cover in each unit listed. Results will be compared to the relevant performance standards to
assess if the standards are being met and if the associated credits are eligible for release.
5.12 Determine if 2 native woody species have 10% or greater cover in the Wetland
Tree/Shrub planting areas in Units A, B, C, and E (Year 10)
(Performance Standards A/B-7C, C-713, and E-711)
Using the aerial cover by species data collected in Year 10 for the Wetland Tree/Shrub planting
areas in Units A, B, C, and E determine if 2 native woody species each provide 10% cover in
each unit listed. Results will be compared to the relevant performance standards to assess if the
standards are being met and if the associated credits are eligible for release.
5.13 Estimate aerial cover of native woody vegetation in the Upland and Riparian
Upland planting areas in Units A, B, C and E (Years 5 and 10)
(Performance Standards A/B-5C, C-5C, and E-5C).
The aerial cover of native woody vegetation in the Upland and Riparian Upland planting areas in
Units A, B, C, and E will be determined in Years 5 and 10 using randomly placed sample units
and line -intercept method as described in Elzinga et al. (1998) or other statistically appropriate
methods. Data will be collected by species. Transects will be placed perpendicular to the
strongest environmental gradient. Sampling objectives are to be 80 percent confident that the
estimate is within 20 percent of the true value. Estimates derived from sampling will be
compared to the relevant performance standard to assess if the standards are being met and if the
associated credits are eligible for release.
5.14 Determine if 3 native woody species have 3% or greater aerial cover in the Upland
and Riparian Upland planting areas in Units A, B, C, and E (Year 5)
(Performance Standards AB-51), C-51), and E-51)).
Using the aerial cover by species data collected in Year 5 for the Upland and Riparian Upland
planting areas in Units A, B, C, and E determine if three native woody species each provide three
percent cover in each unit listed. Results will be compared to the relevant performance standards
to assess if the standards are being met and if the associated credits are eligible for release.
App A Sp6ngbrook_Mmdaing Plan_041906.doc
Appendix A May 2006
Monitoring Plan Page A-9
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
5.15 Determine if 2 native woody species have 7% or greater aerial cover in the Upland
and Riparian Upland planting areas in Units A, B, C, and E (Year 10)
(Performance Standards A/11-71), C-71), and E-71)).
Using the aerial cover by species data collected in Year 10 for the Upland and Riparian Upland
planting areas in Units A, B, C, and E determine if two native woody species each provide seven
percent cover in each unit listed. Results will be compared to the relevant performance standards
to assess if the standards are being met and if the associated credits are eligible for release.
5.16 Determine density of living native conifer plantings in the Forested Wetland
Enhancement areas in Units C, D, and E (Years 1, 5 and 10)
(Performance Standards C-311, D-213, and E-3C)
In Years 1, 5, and 10, the density of living native conifers in the Forested Wetland Enhancement
Areas shown on the treatment maps (Figures 2-1 through 2-5) will be determined using randomly
placed un-equal area belt transects as described by Stehman and Salzer (2000) or other methods
determined appropriate for the site. This estimate will include any natural recruitment of native
conifer species in addition to planted materials. Transects will be randomly placed along a
perpendicular baseline, with the long axis of each transect running parallel to the strongest
environmental gradient. Results will be compared to the relevant performance standards to
assess if the standards are being met and if the associated credits are eligible for release.
5.17 Determine if at least one living native tree is present per planting hummock in Units
A and B (Years 5 and 10)
(Performance Standard A/B- 8)
Locate planting hummocks in Units A and B in Years 5 and 10. Count the number of living
native trees per hummock and determine if each hummock has at least one living native tree
present. Results will be compared to the relevant performance standards to assess if the
standards are being met and if the associated credits are eligible for release.
5.18 Identify and remove any purple loosestrife, English ivy, and/or Japanese knotweed
(Years 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10)
(Performance Standards A/B-9, C-8, D-3, and E-8)
Walk through all units to identify existing populations of purple loosestrife, English ivy,
Japanese knotweed, and/or any other noxious weeds listed for control by the King County
Noxious Weed Board (http://dnr.metrokc.gov/wlr/lands/weeds/laws.htm). Mark all invasive
species populations needing control with flagging and/or GPS data and notify appropriate
WSDOT staff to schedule removal of the target species.
5.19 Determine the extent of un-vegetated open water in Units A, B and E during the
summer monitoring visit (Years 3, 5, and 10) (Performance Standards A/11-213 and
E-2B)
During the summer formal monitoring visits make a qualitative estimate of the extent of un-
vegetated open water present in Units A, B, and E. The extent of un-vegetated open water in
these units is not to exceed 10% of the any one unit.
5.20 Determine if inundation is still present in the Northern portion of Unit D on June
151h (Years 3 and 7) (Performance Standard D-113)
App A Spnngbrook_Monitaing Plan_041M.doc
Appendix A May 2006
Monitoring Plan Page A- 10
FINAL DRAFT
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
6.0 REFERENCES
Cowardin, L.M., and V. Cargter, F.C. Golet, and E.T. LaRoe. 1979. Classification of Wetlands
and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service. FWS/OBS
79/31.
Elzinga, C. L., D. W. Salzer, and J. W. Willoughby. 1998. Measuring and Monitoring Plant
Populations. Bureau of Land Management Technical Reference 1730-1, BLM/RS/ST-
98/005+1730. National Business Center, Denver, CO.
Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical
Report Y-87-1, US Army Engineer Waterways Experiment Station, Vicksburg, MS.
Stehman, Stephen V. and Daniel W. Salzer. 2000. Estimating Density From Surveys Employing
Unequal -Area Belt Transects. WETLANDS. Vol. 20. No. 3. pp. 512-519. The Society
of Wetland Scientists. Ann Arbor, MI.
Washington State Department of Ecology. 1997
Delineation Manual. Washington State
http://www.ecy.wa.gov/pubs/9694.pdf
Washington State Wetlands Identification and
Department of Ecology. Publication #96-94.
App A Springbrook_Monitoring Plan_041906.doc
Appendix A May 2006
Monitoring Plan Page A-12
Appendix B
Memorandum of Agreement
Appendix D
Agreement between City of Renton and WSDOT
Early Environmental Investments on 1-405
Wetland and habitat mitigation banks such as Springbrook are one way to
implement environmental enhancements to a highway project. As part of
WSDOT's environmental commitment, the environmental team continues
to investigate opportunities for early environmental investments along the
corridor. The team is currently working with jurisdictions to identify sites
such as Springbrook that have potential for early development of mitigation
projects that will offer the most environmental benefit for the dollar.
How is water runoff being managed?
Building new lanes on 1-405 will create additional surface water runoff that
must be captured and cleaned. In the past, stormwater detention ponds,
such as the one pictured top right, have been used. Stormwater detention
ponds capture and store water runoff before it reaches a stream system.
While methods like this manage water quality and quantity, they are
expensive to build, focus on minimizing negative impacts, and provide only
the minimal required benefits.
A better potential solution is to create a wetlands restoration site, pictured
below right. Capturing surface water upstream from the highway and
detaining it in a more natural environment focuses on maximizing positive
impacts to the watershed and can achieve additional environmental benefits
at the same or less cost. WSDOT is employing this new approach on a
variety of highway projects throughout the State.
What are the benefits to a watershed approach to
mitigation?
• Targets environmental improvement investments to those areas that will
have the greatest long-term environmental benefit (vs. providing short-
term spot treatments)
• Addresses how the watershed is functioning as a whole, rather than
looking solely at the impact site and making minor improvements
• Provides opportunities to restore natural processes, making the watershed
more biologically productive and reducing long-term maintenance costs
around streams and wetlands
• Uses resources more efficiently. The 1-405 project team is conducting
cost -benefit analyses on conventional vs. alternative mitigation options
• Costs less in challenging topography, such as steep slopes, high
groundwater or wetlands
WSDOT is currently working on project -level environmental assessments
to ensure that the project will avoid or compensate for environmental
impacts. If you'd like to learn more, or be part of this process, please visit
the project website at: www.wsdot.wa.gov/projects/1405.
Engineered Flow Control
Example: stormwater detention pond
Restoring Natural
Flow Control
Example: wetlands restoration
What is meant by the "watershed
approach" to mitigation?
New watershed characterization
methods integrate the mitigation of
wetland, riparian, floodplain, and
stormwater impacts by restoring the
landscape's capacity to provide
necessary functions, while increasing
the environmental benefits.
AdW
�TWashington State
April 21, 2005 vW— Department of Transportation
Congestion Relief & Bus Rapid Transit Projects
Springbrook Wetland and Habitat Mitigation Bank
What is a Wetland
Mitigation Bank?
A "savings account" for
mitigation
• Wetland site set up in advance
of project development and
wetland impacts.
• Consolidates mitigation for
multiple small wetland impacts
into one large site with greater
ecological value —because the
site generates ecological
benefits early, the value
increases as the site matures.
• Compensates for wetland
impacts associated with various
project developments that
occur within the vicinity or
service area of the mitigation
bank.
What are credits?
• "Credits" are the bank site's net
increase in ecological
functioning.
• Credits can be purchased or
withdrawn and used to make
up for unavoidable wetland
impacts.
Why Springbrook?
Springbrook is a piece of property along Springbrook Creek in Renton, WA,
that the Washington State Department of Transportation (WSDOT) and City
of Renton are partnering on to become a thriving wetland site that will provide
environmental benefits for years to come. One of the goals for 1-405, as stated
in the 2002 environmental impact statement (EIS), is to "leave the environment
better than if the project had never been built." That is, to enhance the environ-
ment, bringing it up to modern standards while the 1-405 Project is being
constructed.
Wetland and habitat mitigation— the right thing to do
WSDOT works hard to avoid impacts to the environment when building a
transportation facility, such as 1-405. Sometimes effects to the environment are
unavoidable, and then WSDOT is committed to minimizing these effects. For
example, if a highway needs to run through one or more existing wetlands,
WSDOT constructs new wetlands to make up for the loss to the environment
— this is called environmental mitigation. Springbrook is one large wetland
mitigation site that can provide many more ecological benefits than multiple
smaller sites (see the list of benefits inside).
Why do we call Springbrook a mitigation bank?
When constructing a project such as a highway or building, the developer is
required under federal, state and local laws to provide mitigation for impacts
to the environment. With a large wetland mitigation site such as Springbrook,
WSDOT and the City of Renton have an opportunity to enhance the environment,
and so do other development projects in the area. The Springbrook site will
provide a certain number of credits that other projects can purchase for their
own environmental mitigation needs. Springbrook becomes a bank where
projects can withdraw credits to make up for unavoidable wetland impacts.
Today, Springbrook is an area of adjacent forested properties in
the xx area of Renton south of 1-405. Ideal for future wetland
enhancements, the property is... (something about the characteristics
making it a good candidate for mitigation).
Washington State
April 21, 2005 vAF Department of Transportation
The woody debris and swampy marsh shown here provides ideal
conditions for wetlands and habitat to thrive.
Congestion Relief & Bus Rapid Transit Projects
How does the Springbrook Wetland and Habitat Bank proposal
ecologically support WSDOT's environmental commitments?
• Increases habitat diversity and
develops habitat conditions
• Improves water quality and
enhances hydrologic function
• Removes historic wetland fills
• Restores and creates a larger,
connected site - 20 acres of
wetlands
• Enhances 110 acres of
wetlands and buffer
• Enhances 112 mile of riparian
area
• Restores and re -connects
wetlands and wildlife habitat
• Provides long-term protection
of the on -site wetlands
• Improves and protects
systems in the area before
opportunity is lost
• Mitigates unavoidable impacts
• Coordinates/Integrates with
surrounding land use
• Considers future infrastructure
developments like utilities,
roads & trails
Springbrook helps WSDOT
`i'
meet environmental goals
.,
I r_
I
Follow through on the 1-405 Corridor
—
Final Environmental Impact
Statement (FEIS) commitment to
"early action" environmental
r
solutions, such as a mitigation bank
(
—
Meet commitments made to seek
larger environmental projects with
a watershed approach
r t18M ""WMi as
Collaboration with local partners
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Springbrook Mitigation Area we Existing Trail _ Parcel Boundary
—• Proposed Flow Ili Stop log Weir( ❑ Created Welland
0- Existing Channel — Springbrook Creek Existing Wetland
New Channel Other Mitigation Sites Upland
- Proposed Drainage Pipet
Hummock O Existing Pond
1. A stop log weir intercepts the water flowing down the stream (in theory,
all of the water coming out of the watershed) to determine flow rates
and to track seasonal and annual patterns.
Z Hummocks are small, rounded or cone -shaped, low hills that provide
refuge for habitat.
3. Low head berms are mounds of dirt and plantings on the banks of rivers
and wetlands
What are the benefits to the mitigation banking approach over
traditional methods?
elf
1 acre wetland impact
Traditionally, WSDOT would
enhance small wetland sites
near the affected area to mitigate
for one acre of wetland impact.
What is the timeline for Springbrook and the Renton Nickel Improvement Projects?
7104 Springbrook Site
2/07 SorinabrookAward Contract
"Mitigation banking projects like Springbrook provide a basis
for early collaboration among transportation and
environmental staffs, the public, and regulatory agencies to
explore areas where impacts must be avoided and identify
areas for mitigation investments. This can lead to mitigation
strategies that are both more economical and more effective
from an environmental stewardship perspective than
traditional project -specific mitigation measures."
— FHWA Guidance (February, 2005) "Linking the Transportation
Planning and National Environmental PolicyAct (NEPA) Processes"
The banking approach
sets aside a larger,
connected wetland area
with credits that can be
sold for wetland mitigation.
What are the costs associated with mitigation banking and traditional mitigation for WSDOT in the region?
In the Traditional Approach (above left), it would cost
In the Springbrook example (above right), it would cost
$750,000 to provide mitigation for one acre of impact to
between $270,000 to $400,000 to purchase one credit
Category Two wetland (which may require two acres of
at the bank for one acre of impact to Category Two
land if a 2:1 ratio was negotiated for concurrent mitigation).
wetland.
Cost savings at the Springbrook bank would result from:
• Better mitigation ratios with banking because of early
action, protection, and regulatory oversight
• No right of way costs to WSDOT with Renton
partnership
5107 Springbrook
Start Construction
5108 Springbrook Construction Complete
2003 2004 > 2005 > 2006 I 2007 I I > 2008 I > 2009 > 2010
7103 1/05 9106 Renton Nickel FONSI 3.107Permitting 4107 Renton Nickel 11107 Renton Nickel DB 12/10 Renton Nickel Construction Complete
Renton Nickel Improvement Project Funding Renton Nickel EA Scoping Begins Complete RFP issued Construction begins
April 21, 2005 TrWashington State
Department of Transportation
Noxious Weeds are non-native plants
introduced to Washington state, either
deliberately or accidentally through
human activities. Because of their
aggressive growth and lack of natural
enemies in Washington, these plants
can be highly destructive,
competitive, or difficult to control.
These exotic species can be
damaging to our economy and natural
resources, as they:
• reduce crop yields
• destroy plant and animal
habitat
• reduce recreational
opportunities (e.g„ fishing,
hunting, swimming, and
hiking)
• clog waterways
• decrease land values
• can poison humans and
livestock.
To help protect the state's resources
and economy, the Washington State
Noxious Weed Control Board adopts
a State Noxious Weed List each year
(WAC 16-750). This list classifies
weeds into three major classes — A,
B, and C — based on the stage of
invasion of each species and the
seriousness of the threat they pose to
Washington. This classification
system is designed to:
• prevent small infestations from
expanding by eradicating them
when they are first detected
• restrict already established
weed populations to regions of
the state where they occur
and prevent their movement to
uninfected areas
• allow flexibility of weed control
at the local level for weeds
that are already widespread.
To learn more about noxious weeds and
noxious weed control in Washington,
please contact:
Washington State Noxious Weed
Control Board
P.O. Box 42560
Olympia, WA 98504-2560
(360)-902-1901
noxiousweeds@agr.wa.gov
Website: http://www.nwcb.wa.gov
M
Washington State Department of
Agriculture
21 North First Avenue #103
Yakima, WA 98902
(509)225-2604
1011
King County Noxious Weed
Control Board
201 South Jackson, Suite 600
Seattle, WA 98104
(206)296-0290
Website: http://dnr.metrokc.gov/weeds/
Please help protect Washington's
economy and environment from
noxious weeds!
2006
Washington
State
Noxious Weed
List
Floating primrose -willow, Ludwigia peploides,
a new Class A Noxious Weed
Image from Britton, N.L. and A. Brown. 1913. Illustrated Flom of
the Northam States and Canada. Vol. 2: 589. Courtesy of the
Kentucky Native Plant Society. Scanned by Omnitek, Inc.
Class A Weeds: Non-native species
whose distribution in Washington is still
limited. Preventing new infestations and
eradicating existing infestations are the
highest priority. Eradication of all Class
A plants is required by law.
Common Name
bean -caper, Syrian
blueweed, Texas
broom, Spanish
buffalobur
clary, meadow
cordgrass, dense flower
cordgrass, salt meadow
crupina, common
flax, spurge
four o'clock, wild
goatsrue
hawkweed, yellow devil
hogweed, giant
hydrilla
lohnsongrass
knapweed, bighead
knapweed, Vochin
kudzu
lawnweed
mustard, garlic
nightshade, silvedeaf
'primrose -willow,
floating
sage, clary
sage, Mediterranean
spurge, eggleaf
starthistle, purple
'sweetgrass, reed
thistle, Italian
thistle, milk
thistle, slenderflower
velvetleaf
woad dyers
Scientific Name
Zygophyllum fabago
Helianthus cilians
Spartium junceum
Solarium rostratum
Salvia pratensis
Spartina densiflora
Sparttna patens
Crupina vulgans
Thymelaea passenna
Mirabilis nyctaginea
Galega officinalis
Hieracium flonbundum
Heracleum
mantegazzianum
Hydnlla verticillata
Sorghum halepense
Centaurea
macrocephala
Centaurea nigrescens
Puerana montana var.
lobata
Saliva sessilis
Alliana petiolata
Solanum elaeagnifolium
Ludwigia peploides
Salvia sclarea
Salvia aethiopis
Euphorbia oblongata
Centaurea calcitrapa
Glycena maxima
Carduus pycnocephalus
Silybum mananum
Carduus tenuiflorus
Abutilon theophrasti
Isatis tinctona
New additions to the 2006 Noxious Weed List
Class B Weeds: Non-native species
presently limited to portions of the state.
Species are designated for control in
regions where they are not yet
widespread. Preventing new infestations
in these areas is a high priority. In
regions where a Class B species is
already abundant, control is decided at
the local level, with containment as the
primary goal. Please contact your County
Weed Board to learn which species are
designated in your area.
Common Name
alyssum, hoary
arrowhead, grass -
leaved
blackgrass
blueweed
broom, Scotch
bryony, white
bugloss, common
bugloss, annual
camelthorn
carrot, wild
catsear, common
chervil, wild
cinquefoil, sulfur
cordgrass, smooth
cordgrass, common
daisy, oxeye
elodea, Brazilian
fanwort
fieldcress, Austrian
floating heart, yellow
gorse
hawkweed, mouseear
hawkweed, orange
hawkweed, polar
hawkweed, queen -devil
hawkweed, smooth
hawkweed, yellow
hedgeparsley
Scientific Name
Berteroa incana
Sagittana graminea
Alopecurus
m yos uroides
Echium vulgare
Cytisus scopanus
Bryonia alba
Anchusa officinalis
Anchusa arvensis
Alhagi maurorum
Daucus carota
Hypochaens radicata
Anthnscus sylveshis
Potentilla recta
Spartina alterniflora
Spartina anglica
Leucanthemum vulgare
Egena densa
Cabomba caroliniana
Ronppa austnaca
Nymphoides peltata
Ulex europaeus
Hieracium pilosella
Hieracium aurantiacum
Hieracium atratum
Hieracium glomeratum
Hieracium laevigatum
Hieracium caespitosum
Tonlis arvensis
Class B Weeds continued
............. 1._ .......- ...
helmet, policeman's
herb -Robert
houndstongue,
indigobush
knapweed, black
knapweed, brown
knapweed, diffuse
knapweed, meadow
knapweed, Russian
knapweed, spotted
knotweed, Bohemian
knotweed. giant
knotweed. Himalayan
knotweed, Japanese
kochia
lepyrodiclis
loosestrife, garden
loosestrife, purple
loosestrife, wand
nutsedge, yellow
oxtongue, hawkweed
parrotfeather
pepperweed, perennia
primrose, water
puncturevine
ragwort, tansy
saltcedar
sandbur, longspine
skeletonweed, rush
sowthistle, perennial
spurge, leafy
spurge, myrtle
starthistle, yellow
swainsonpea
thistle, musk
thistle, plumeless
thistle, Scotch
toadflax. Dalmatian
watermilfoil. Eurasian
Impatiens glandulifera
Geranium robertianum
Cynoglossum officinale
Amorpha fruticosa
Centaurea nigra
Centaurea jacea
Centaurea diffusa
Centaurea jacea x nigra
Acroptilon repens
Centaurea biebersteinii
Polygonum bohemicum
Polygonum
sachalinense
Polygonum
polystachyum
Polygonum cuspidatum
Kochia scopana
L epyrodichs
holosteoides
Lysimachia vulgans
Lythrum salicana
Lythrum virgatum
Cyperus esculentus
Picns hieracioides
Mynophyllum aquaticum
I Lepidium latifolium
Ludwigia hexapetala
Tnbulus terrestns
Seneciojacobaea
Tamanx ramosissima
Cenchrus longispinus
Chondnlla juncea
Sonchus arvensis
ssp. arvensis
Euphorbia esula
Euphorbia myrsinites
Centaurea solstitialis
Sphaerophysa salsula
Carduus nutans
Carduus acanthoides
Onopordum acanthium
Linana dalmatica ssp.
dalmatica
Mynophyllum spicatum
Class C Weeds: Noxious weeds that
are already widespread in Washington or
are of special interest to the state's
agricultural industry. The Class C status
allows counties to enforce control if
locally desired. Other counties may
choose to provide education or technical
consultation.
Common Name
babysbreath
beard, old man's
bindweed, field
butterfly bush
canarygrass, reed
cockle, white
cocklebur, spiny
cress, hoary
dodder, smoothseed
alfalfa
goatgrass, jointed
groundsel, common
hawkweed, nonnative
and invasive species not
listed elsewhere
henbane, black
iris, yellow flag
ivy, English
four cultivars only
mayweed, scentless
poison -hemlock
pondweed, cudy-leaf
reed, common
(nonnative genotypes)
rye, cereal
spikeweed
St. Johnswort, common
tansy, common
thistle, bull
thistle, Canada
toadflax, yellow
water lily, fragrant
whitetop, hairy
willow -herb, hairy
wormwood. absinth
Scientific Name
Gypsophila paniculata
Clematis vitalba
Convolvulus arvensis
Buddleja davidii
Phalans arundinacea
Silene latifolia ssp. alba
Xanthium spinosum
Cardana draba
Cuscata approximata
Aegilops cylindnca
Senecio vulgans
Hieracium spp.
Hyocyamus niger
Ins pseudoccrus
Hedera helix'Baltica'
Hedera helix 'Pittsburgh'
Hedera helix 'Star'
Hedera hibernica
Hibernica'
Matricana perforata
Conium maculatum
Potamogetoo cnspus
Phragmites austratis
Secale cereale
Hemizonia pungens
Hypencum perforatum
Tanacetum vulgare
Cirsium vulgare
Cirsium arvense
Linaria vulgans
Nymphaea odorata
Cardana pubescens
Epilobium hirsutum
Artemisia absinthium
1-405 SPRINGBROOK MITITGATION BANK PAGE 1 of 1
PROJECT DEVELOPMENT / PLANT ORDER 5:55 PM Tue 5/16/06
SCHEDULE
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Start
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Tue 7126106 -
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KC Metro reviews and executes ..it Claim
5 days
Wed 6117/06
Tue 523/06 48
s0
0 days:
50
City obtains Quit claim from KC Metro
0 days
Tue 523106
Tue 523/06 49
63
13 days
611
Olympic Pipeline - Property interest
7 days
Mon 6115/06
Tue 5123106
33 days:
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52 I
Prepare Quit Claim forOlympic to release property rights
2 days
Mon 5/15106
Tue 5/16/06 -
53
0 days
[�
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Olympic reviews and executes Quit Claim
5 days
Wed 5117/06
Tue 5/23/06 52
54
0 days
li
54
City obtains Quit claim from Olympic
0 days
Tue 523106
Tue 523106 53
63
13 days
6421
55
Land Rights Map
15 days
Mon 5/15/06
Fri 6/2/06
95 days j
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56
Draft land rights map completed by Inca
5 days
Mon 5/15/D6
Fri 5119/D6
57
0 days
57
Draft land rights map review by WSDOT/CoR
5 days
Mon 522)06
Fri 5126106 56
58
0 days
58
Finalize Land Rights Map
5 days
Mon 529106
Fri 62/06 57
59
0 days
59
Land Rights Map Complete
0 days
Fn 6006
Fri 6006 58
95 days
r 80
Lot Line Adjustment - Sundry Site Plan
30 days
Mon 5115106
Fri 6/23106
20 days
61
Complete City/WSDOT agreement for 50/50 spkl
5 days
Mon 5115106
Fri 5119/06
62
0 days ;
62
Provide NTP for Task B to Inca
0 days
Fri 5119106
Fri 5119/06 61
63
15 days I
-
L-�
63
Incorporate ownership adjustments
10 days
Mon 6/12106
Fri 623106 38,41 44.46,50.54
64
0 days
Lot Line Adlusment Map Complete
0 days
Fri 623106
Fri 623/06 63
20.65
0 days
6123
i 65
Right of way Certified
70 days
Mon 626/06
Fri 7/7/06 64
79
20 days
6B :Permitting
20 days
Mon 5116/06
Fri 619106
40 days
67
City of Renton Public Works
20 days
Mon 5115/06
Fn 6/9106
73
0 days',
i
......,88......
COE 404
10 days
Mon 5115/06
Fri 526/06
73
10 days':
69 �,
Ecology 401
10 days
Mon 5/15I06
Fri 526106
72.73
0 days
70....
Ecology 402 (NPDES)
20 days
Mon 5115/06
Fri 619106
73
0 days
KC Drainage District
20 days
Mon Sit V06
Fri 619106
73
0 days
(-
72--
Ecology CZMA
5 days
Mon 529/06
Fri 62/06 69
73
5 days
73
Permits Complete
0 days
Fri 619/06
Fri 6/9106 67.68,69.70,71,72
79
40 days
74 ''.
PSBE Design
60 days
Mon 6116/06
Fri 814106
0 days
75
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0 days
Fri 5126/06
Fri 5126/06 76
78
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50 dayx
Mo., S:2i1i06
4:p�
1
79
Project Ad (Proposed August 14, 2006)
- 0 days
Fri $14/06
Fri 8/4106 65,73,78
81
0 days
14
8 i
Contractor Selection
70 days
Mon W106
Fri 11110/06
0 days
81
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62
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20 clays
Mon r02.m6
Fn 10.2.7!06 82
54
0 days
84
NTP
0 days
Fri 1027/D6
Fri 1027/06 83
85
0 days z
10127
86
86
Place Plant Order
0 days
Fri 11/10/06
Fri 11110/06 85
0 days;
-.
- ♦ 111
Complete Project Developmenlmpp
Page 1
UTILITIES COMMITTEE
COMMITTEE REPORT
V;130 Z - 1?-aoo6 ,
June 19, 2006
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument
(June 12, 2006)
in!_iTY SYS! CMS
The Utilities Committee recommends concurrence in the staff recommendation to approve the
Springbrook Creek Wetland and Habitat Mitigation Bank Instrument.
The Committee further recommends that the resolution regarding the approval of the
Mitigation Bank Instrument and the other agreements, subject to Council review and approval
of the other agreemensbe presented for reading and adoption
Dan Clawson, Chair
4
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Terri Brier ,Vice Chair
r 2
Dems W. Law, Member
cc: Lys Hornsby, Utility Systems Director
Ron Straka, Surface Water Utility Engineering Supervisor
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