Res 03-384RESOLUTION NO., 03-384
A RESOLUTION OF THE CITY OF FEDERAL WAY,
WASHINGTON, TO FORM STEEL LAKE MANAGEMENT
DISTRICT NUMBER 1 AND SETTING A PUBLIC
HEARING ON THE FORMATION OF THE PROPOSED
DISTRICT.
WHEREAS, the City of Federal Way completed the Steel Lake Aquatic Plant
Management Plan in December of 1995 and updated this plan in April of 2003 (renamed the
Steel Lake Integrated Aquatic Vegetation Management Plan) (the "Plan") (Attachment A); and
WHEREAS, the Plan was initiated because of citizen interest in the long-term protection
of Steel Lake; and
WHEREAS, Steel Lake contains significant natural resources, such as wetlands, and
forms the headwaters for Redondo Creek; and
WHEREAS, the existing lake quality supports fishing, wildlife habitat, swimming,
boating, visual aesthetics, waterfront property values, irrigation, and other beneficial uses; and
WHEREAS, pursuant to RCW 35.21.403 and RCW 36.61, a lake management district
can be formed to generate funds for financing lake improvement and maintenance projects as
recommended in the Steel Lake Integrated Aquatic Vegetation Management Plan; and
WHEREAS, the City of Federal Way is committed to a good faith effort of continuing
these activities; and
WHEREAS, the Steel Lake community has demonstrated support for the formation of a
lake management district through submittal of a petition (Attachment B) pursuant to the
requirements of RCW 36.61; and
Res. # 03-38/, Page 1
WHEREAS, the hearing notice requirements of RCW 36.61 will provide an opportunity
to evaluate property owner interest in lake management district activities.
NOW THEREFORE, THE CITY COUNCIL OF THE CITY OF FEDERAL WAY
HEREBY RESOLVES AS FOLLOWS:
Section 1. Intention to Form Steel Lake Management District. The City of Federal Way
City Council declares, by passing this resolution, its intention to conduct the activities required
by RCW 36.61 for the establishment of Lake Management District Number 1 (Steel Lake) (The
"District"). The nature of the proposed activity to be undertaken by the District is the continued
implementation of the Steel Lake Integrated Aquatic Vegetation Management Plan. Special
assessments totaling $13,598 will be collected annually to finance the District activities, with the
total amount to be collected during the life of the District being $166,440, which includes an
automatic inflation increase based upon the Seattle Consumer Price Index not to exceed five
percent in any given year. The proposed duration of the District is ten years from the date such
District is actually formed by ordinance. The proposed boundaries of the District encompass all
properties adjacent to Steel Lake with lake front footage. The proposed rate structure is based on
equal charges for similar parcels. Undeveloped parcels will be charged $30 per year. Single
family developed parcels will be charged $85 per year. The multi-family parcels will be charged
$275 per year. The City of Federal Way parcel will be charged $2,048 per year. The Department
ofFish and Wildlife parcel will be charged $3,500 per year.
Section 2. Public Hearing. A public hearing conducted by the City of Federal Way City
Council shall be held on the formation of the proposed District:
DATE: June ! 7, 2003
TIME: 7:00 pm or shortly thereafter
Res. # 03-384 Page 2 _
PLACE: City of Federal Way City Hall
35530 1st Way South
Federal Way, WA
Section 3. Establishment of Advisory Committee. If Lake Management District Number
1 is formed, the City of Federal Way City Council will establish a non-paid Advisory Board of
lakefront property owners representative of the diversity among property owners around Steel
Lake to oversee the implementation of the Lake Management District program and to assist the
City of Federal Way in establishing annual budgets and work plans for the use of Lake
Management District revenues and expenditures. The Advisory Board will meet regularly as
determined by the Board, propose annual budgets for Lake Management District expenditures to
the City of Federal Way, educate its neighbors on Lake Management District issues, and submit
annual reports of Lake Management District activities to the City of Federal Way.
Section 4. Public Notice. The City of Federal Way Clerk is hereby directed to publish
and mail notices as required by RCW 36.61.
Section 5. Severabilit¥. If any section, sentence, clause or phrase of this resolution
should be held to be invalid or unconstitutional by a court of competent jurisdiction, such
invalidity or unconstitutionality shall not affect the validity or constitutionality of any other
section, sentence, clause or phrase of this resolution.
Section 6. Ratification. Any act consistent with the authority and prior to the effective
date of the resolution is hereby ratified and affirmed.
Section 7. Effective Date. This resolution shall be effective immediately upon passage by
the Federal Way City Council.
Res. # 03-386 Page 3
RESOLVED BY THE CITY COUNCIL OF THE CITY OF FEDERAL WAY,
WASHINGTON, this 6th day of 1,1ay ,2003.
CITY OF FEDERAL WAY
, N."CH~-'"~TbCE GREEN, MC
APPROVED AS TO FORM:
PATRICIA/k57RICHARDSON, CITY ATTORNEY
FILED WITH THE CITY CLERK:
PASSED BY THE CITY COUNCIL:
RESOLUTION NO.
4130103
5106/03
03-384
Res. # 03-384 Page 4
FINAL DRAFT
Attachment "A"
STEEL LAKE IAVMP
APRIL 3, 2003
1
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
PROBLEM STATEMENT
Steel Lake is located in the City of Federal Way in King County, Washington. It is a
small (47 acres), shallow (maximum depth 24 feet, mean depth 13 feet) lake with a
watershed area of 304 acres that is primarily developed as residential and commercial
property. The only source of surface water inflow to the lake is from city stormwater
outfalls.
In the past decade, infestations of non native aquatic plants Eurasian watermilfoil
(Myriophyllum spicatum) and fragrant water lily (Nymphae odorata) have occurred on
several occasions that colonized lake areas in large quantities. Because Steel Lake is a
shallow system, a large portion of the surface area of this lake is available for aquatic
weed colonization.
Aquatic weed infestations on Steel Lake, such as those exhibited by M Spicatum
(milfoil), are well documented. In the early 1990s, the lake became fully infested with
milfoil, which dominated the entire littoral zone. Extensive milfoil colonies near the
beach, shoreline, and homeowner docks posed serious threats to swimmers and
significantly reduced native plant communities. In addition, the public fishing dock was
surrounded by milfoil beds that made fishing from the shore nearly impossible. A whole
lake application using fluridone (Sonar®) in 1994 was required to treat the aquatic plant
problem. In 2001, milfoil re- infested Steel Lake, this time appearing as a pioneering
colony. It was spot treated with 2,4 -D (AquaKleen®) in August of 2002.
It is likely that milfoil is being spread on boats that enter the lake at the public boat
launch. These boats tend to travel from lake to lake in the Federal Way region. Because
Star Lake and Lake Killarney are within a few miles distance of Steel Lake, they (and
other nearby systems) are threatened with introductions of milfoil if Steel Lake is not
controlled.
Non native fragrant water lily, a noxious weed, continues to colonize the western end of
the lake and other scattered areas where water depths are limited. The lilies, in
combination with the very shallow water depth have greatly restricted use of this portion
of the lake. Large sections of root and plant masses break away and float to the surface of
the lake, forming unsightly clumps and causing potential boating safety problems.
Through the years, individual homeowners have implemented lily treatment and control,
but these efforts are offset if adjacent properties are not maintained. Consequently, the
lake requires a comprehensive aquatic weed management approach.
Aquatic weed infestations in Steel Lake threaten the investment that Steel Lake residents
have made to protect their property values and to preserve the lake's aesthetic beauty,
2
STEEL LAKE IAVMP APRIL 3, 2003
FINAL ORAFT
recreational attributes, and wildlife habitat. The Steel Lake Community recognizes that a
concerted, long -term effort is necessary to control future aquatic weed infestations.
The facts listed above were used to create a problem statement for Steel Lake. The
purpose of the problem statement is to describe as clearly as possible how the lake and
it's inhabitants are being negatively impacted by aquatic plants.
Problem Statement
Aquatic plants, including the non native species Myriophyllum spicatum,
(milfoil) in Steel Lake historically have impaired the use and aesthetic value
of the lake. Dense aquatic plant beds have restricted access, fishing,
swimming, sailing, and other types of boating to the mid section of the
lake, due to the obstruction caused by plants in the shallower, near shore
area. In 1993, milfoll was reportedly colonizing areas up to the 15 -foot
depth interval. In addition, other regional lakes are in danger of becoming
infested with milfoil originating in Steel Lake. Because of the lake's shallow
characteristic, submerged plants have the potential to restrict the available
area for recreation activities. The non native lily, Nymphaea sp., (fragrant
water lily) continues to colonize a large portion of the west end of the lake.
The lilies, in combination with the very shallow water depth, have greatly
restricted use of this portion of the lake. Personal efforts to control the
lilies are offset if adjacent properties are not also maintained, and
consequently suffer from the need for a lake -wide approach. Large
sections of root and plant masses break away and float to the surface of
the lake, forming unsightly clumps and create potential boating safety
problems. Property values may be affected by the plant problems. This
may be especially true of the western end of the lake, where water depth
limitations in combination with lily beds are causing the "waterfront" to
move farther from the existing shoreline. A long -term strategy is required
for the control of aquatic plants, and to assure that milfoil does not become
re- established in the lake.
MANAGEMENT GOALS
The Steel Lake Steering Committee has developed the following set of management goals
for the long -term management of aquatic weeds in Steel Lake:
3
STEEL LAKE IAVMP APRIL 3, 2003
FINAL O r
Form a Lake Management District that creates a funding source for all future
aquatic plant management activities, and continue to seek grant opportunities.
Perform annual diver surveys to monitor changes in the aquatic plant community.
Control and contain both milfoil populations and fragrant water lily populations at
as low a density as is environmentally and economically feasible, and at levels
that will not impact public safety or the beneficial uses of the lake.
Reduce all other identified species of noxious weeds as listed in WAC 16 -750 to
levels that do not impact public safety or the beneficial uses of the lake.
Use appropriate aquatic plant control and treatment methods as needed for all
other problematic aquatic weeds, using the best available science to identify and
understand their effects on human, aquatic and terrestrial ecosystems prior to
implementation.
Provide for adequate native vegetation for fish and, if necessary, mitigate for any
negative impacts to fish habitat due to non native plant removal activities.
Continue public education to prevent the introduction of noxious weeds, nuisance
plants and non native animal species to the lake; and to aid in the early detection
of aquatic weed re- infestations.
Continue to involve the Steel Lake Community in the aquatic plant management
process.
PAST MANAGEMENT EFFORTS
Prior to 1993, lake homeowners optioned to contract individually to have their near shore
areas sprayed with glyphosate (Rodeo®) to control lilies. In 1993, the lake became
heavily infested with milfoil. That year, the City of Federal Way and the Steel Lake
Residents' Association (SLRA) formed an advisory committee, and began aquatic plant
management planning. The city and SLRA agreed to combine funds to eradicate the
milfoil infestation. In the spring of 1994, fluridone (Sonar®) was applied by Resource
Management (RMI).
In 1993, the City of Federal Way received an Aquatic Weeds Management Fund Grant
from the Department of Ecology to provide long -term aquatic plant control. The AWMF
Grant was used to contract with Envirovision for the development of an Integrated
Aquatic Vegetation Management Plan (IAVMP). The IAVMP was completed in
December 1995, and approved by the Department of Ecology in February 1996.
Funds collected by the SLRA, combined with a city match, were applied toward several
post- treatment lake surveys. A 1 -year post treatment aquatic plant survey performed by
RMI in 1995 demonstrated that milfoil had not re- infested the lake. Additional follow -up
systematic surveys performed by Herrera Environmental Consultants in 1996 and 1998
4
STEEL LAKE IAVMP APRIL 3, 2003
indicated that the lake had remained free of milfoil. Between 1998 and 2001, no aquatic
weed management efforts (surveys, control, treatment, or public meetings) took place.
In the summer of 2001, the King County Department of Natural Resources and Parks
(through a grant provided by the Department of Ecology), contracted with AquaTechnex
(formerly RMI) to survey Steel Lake for noxious weeds. This simple survey confirmed
that a pioneering level of milfoil had re- established itself in the lake. In the fall of 2001,
the City of Federal Way provided notification of this re- infestation to all affected
residents, primarily those concentrated along the northwest portion of the lake.
Thereafter, the city began to develop a strategy for future aquatic weeds management. In
early 2002, the City applied for an Early Infestation Grant from the Department of
Ecology for short-term milfoil identification, treatment, and control. Following the award
of the grant, AquaTechnex was given city approval to perform a comprehensive
underwater survey for milfoil in August.
In the interim, the city organized two well attended (more than thirty people each) Steel
Lake Residents' meetings in June and July of 2002 to discuss lake management issues,
including future treatment options and funding alternatives. An overview of the Lake
Management District (LMD) formation process was presented at these two public
meetings. In order to discuss and plan aquatic plant management in further detail,
volunteers were solicited to form the Steel Lake Steering Committee.
The underwater survey performed by Aqua Technex in August 2002, specific for milfoil,
indicated that the noxious aquatic weed had spread throughout the littoral zone of the
lake, colonizing a total of five acres. In late August, the lake was spot treated with 2,4 -D
(AquaKleen®). A follow-up visual evaluation performed approximately 5 weeks later
verified that the treatment produced a significant weed kill. The Integrated Treatment
Plan outlined in this IAVMP will address the future management of milfoil infestations.
In addition, some Steel Lake residents elected to spot treat their waterfront for white
water lily in 2002 using Glycosate. Again, Aqua Technex applied the aquatic herbicide,
contracting individually with the interested homeowners. A brief post- treatment
evaluation indicated a moderate lily population reduction. Systematic lake surveys
planned for 2003 will confirm the effectiveness of the lily treatment, and define future
action.
In late 2002, the Steel Lake Steering Committee began to lay the groundwork for a long-
term and effective aquatic weed management program. The Committee began meeting
on a monthly basis to formulate a work plan. The feasibility of forming a LMD was
closely examined and discussed.
During this time, industry professionals from both the public and private sectors were
consulted concerning the LMD process. The Committee recognized that the Department
of Ecology (DOE) is a strong proponent of special purpose districts for managing lakes;
5
STEEL LAKE IAVMP APRIL 3, 2003
ti m DRAFT
and that future DOE grant awards were more likely if a Steel Lake LMD was formed.
These factors led to an agreement that a LMD would be the best solution in providing a
stable source of funds for aquatic plant management activities.
On November 13, 2002, a Steel Lake Community public meeting was held to present the
Committee LMD recommendation. An informal straw vote showed. unanimous support
for LMD formation. As of March 2003, the Steel Lake Committee is pursuing formation
of the LMD through the district formation process defined in RCW 36.61.
LAKE AND WATERSHED CHARACTERISTICS
Location
The Steel Lake watershed is located approximately 20 miles south of Seattle, in the City
of Federal Way, King County, Washington. The watershed is 304 acres in size and drains
a gently sloping topographic area with elevations ranging from 440. feet to 500 feet
(Figure 1). The maximum depth is 24 feet, and the mean depth is 13 feet. Lake depth
contours are depicted in Figure 3. A Sediment Type Map for Steel Lake is depicted in
Figure 4. The entire watershed of Steel Lake lies within the City of Federal Way.
Land Use
Land use in the watershed is primarily comprised of single family residences (Figure 1,
Figure 2, and Table 1). Steel Lake Park, multi family residences, and vacant land
comprise most of the remaining land in the watershed. It should be noted that the sub-
basin boundary g
in Figure 1 and land use estimates in Table 1 are for Redondo Creek sub
basin CPR3, which includes an additional acreage to the north and west of the lake outlet.
In addition, thirteen percent (13 of the Central Puget Sound basin, which includes the
Steel Lake and Redonodo Creek watershed, is available for re- development, including 21
parcels on Steel Lake (11 vacant and 10 re- developable). There are 631 residential
properties in CPR3.
Table 1. Land Use Estimates for the Steel Lake Watershed (Subbasin CPR3)
Land Use Classification (Acres) (Percent)
Commercial 2.9 0.96
Industrial 0.2 0.07
Multi Family 11.1 3.6
Office 2.8 0.92
6
STEEL LAKE IAVMP APRIL 3, 2003
FINAL °RAFT
Common Ownership 1.7 0.57
Park 24.6 8.1
Quasi public 2.2 0.73
Religious Services 3.8 1.2
Single Family 149.8 49.3
Vacant 47.0 15.4
Steel Lake 47.4 15.6
Wetlands 10.4 3.4
Watershed 303 100
TOTAL 303
Shoreline Use
Steel Lake includes 7,123 feet of shoreline (Table 2). The majority of the shoreline
includes lake frontage adjacent to single family property (5,315 feet). Public access to
the lake is from Steel Lake Park, owned and managed by the City of Federal Way. The
Park is located on the south shore of the lake, and includes a public beach area. A public
boat launch, also located on the south shore near the park, is owned by the Washington
Department of Fish and Wildlife (WDFW). There are eleven (11) undeveloped parcels
around the lake. The largest undeveloped parcel (092104 9012) is located at the northwest
corner, and has a shoreline measuring 332 feet, with a portion classified as wetland.
Table 2. Shoreline Use Estimates for Steel Lake
Shoreline Use Total Frontage ok
(ft)
Single family residential 5315 75
Steel Lake Park 875 12
Undeveloped Parcels 477 6.7
Multi- family 392 5.5
Public Boat Launch 64 0.9
Stream and Wetland Locations
Steel Lake forms the headwaters of Redondo Creek. Outflow from the lake generally
occurs only during the wet season (November through June). The lake outlet drains in a
northwest direction from the west end of the lake, passing through a wetland to a culvert
crossing at South 304th Street. The outlet continues to flow in a northwest direction,
passing underneath Pacific Highway South and eventually discharging into Puget Sound
at Redondo Beach in the City of Des Moines. Runoff from the wetland, open space, and
development near the northwest portion does not drain into the lake.
7
STEEL LAKE IAVMP APRIL 3, 2003
Wetlands in the Steel Lake Watershed have been mapped by the US Department of Fish
and Wildlife as part of the National Wetland Inventory (NWI, 1987). Wetlands in Steel
Lake proper have been identified as either open water wetland (lacustrine limnetic) or
aquatic bed wetland (lacustrine- littoral).
This wetland areas was surveyed by Sheldon Associates for the City of Federal Way in
1998, which identified it as a Category I wetland as defined by Federal Way city code
The vegetation of the wetland complex was described as a palustrine- scrub-
shrub /forested seasonally flooded wetland adjacent to Steel Lake and a palustrine-
emergent- semi permanently flooded wetland toward the beginning of Redondo Creek.
On February 24, 2003, a search was conducted by the Washington Department of Natural
Resources of the National Heritage Program database for information on rare plants and
high quality native ecosystems in the Steel Lake watershed. There is no information on
significant features within this study area (Moody, 2003, DNR).
Non -point Nutrient Source Locations
The majority of surface water is conveyed to the lake from the 304 -acre watershed
through the city's stormwater system, and enters the lake via 14 stormwater outfalls
located around the perimeter. (Figure 1). The largely urbanized nature of the watershed
can be expected to contribute typical urban area nutrient related pollutants to the lake, in
particular nitrogen and phosphorous. Significant pollutant sources in the watershed
including landscaping, gardening, large flocks of Canada geese at Steel Lake Park, and
vehicle washing all have the potential to contribute nutrients into the lake.
Lakeshore residences and most of the development in the watershed are connected to the
Lakehaven Utility District sanitary sewer system. Lakehaven Utility District does not
have a record of a documented sanitary sewer overflow in the Steel Lake region. In
addition, Lakehaven does not have records concerning on -site household septic systems
(Asbury, 2003, personal communication).
Failing septic systems may also be a source of pollutants such as nutrients and bacteria to
Steel Lake. The 1995 Steel Lake IAVMPA reported that approximately 35 acres of
single- family residences, located in the northwest and northeast portions of the watershed,
were served by on -site septic systems (Federal Way Water and Sewer and RPA, 1992).
The King County Health Department does not maintain a list or map of household septic
systems, or the incidence of septic system failure in the Steel Lake watershed.
Information and as- builts may only be obtained through a request that includes details
concerning the specific address or parcel (Bishop, 2003, KC Health).
Large concentrations of non -point nutrients can increase the biological productivity of the
lake, and stimulate plant growth. Data collected by the King County Lake Stewardship
Volunteer Monitoring Program include levels of nitrogen and phosphorous; and
concentrations of phytoplankton and chlorophyll. This information is used to calculate
the Trophic State Index (TSI) for the lake, a measurement if the lake's health. The most
8
STEEL LAKE IAVMP APRIL 3, 2003
FINAL
up -to -date water quality data and TSI values provided by King County Lake Volunteers
are included in the Water Quality section of the IAVMP.
The City of Federal Way is participating in a Canada geese management program at Steel
Lake Park with the US Department of Agriculture (USDA). In 2002, nuisance flocks of
geese were removed from the park as a part of this program. In successive years, Parks
Department staff will employ non lethal geese management techniques (using bird-
bangers and other harassment tools) to control populations. A reduction in numbers of
Canada geese visiting the park will result in a reduction in nutrients entering the lake.
Water Source
Steel Lake, located in the City of Federal Way, is 46 acres in size with a watershed area
of 243 acres. Steel lake is relatively shallow with a mean depth of 13 feet, a maximum
depth of 24 feet, and a lake volume of 600 acre -feet. Physical characteristics of Steel
Lake are summarized in Table 3.
The majority of surface water enters the lake via 14 stormwater outfalls located around
the perimeter of the lake (Figure 1). No streams flow into the lake.
Table 3. Physical Characteristics of Steel Lake and Its Watershed
Characteristic English Units Metric Units
Watershed area 304 acres 98.3 hectares
Surface area 47 acres 18.6 hectares
Lake volume 600 acre -ft 7.4 x 10 cubic meters
Maximum depth 24 feet 7.3 meters
Mean depth 13 feet 4.0 meters
Lake altitude 440 feet 134.1 meters
Shoreline length 1.3 miles 2.1 kilometers
Flushing rate 0.77 times /year 0.77 times /year
Water Quality
The assessment of biological activity (or trophic state) can be classified into three general
categories of lake water quality: oligotrophic, mesotrophic, and eutrophic. Lakes with low
concentrations of nutrients and algae and high transparency (or clarity) are considered
oligotrophic. A lake with high concentrations of nutrients and algae and low transparency
is considered eutrophic. Lakes whose quality ranges between eutrophic and oligotrophic
are considered mesotrophic.
9
STEEL LAKE IAVMP APRIL 3, 2003
One of the most common measures used to calculate a lake's water quality classification
is the numerical trophic state index (TSI) developed by Robert Carlson (1977). This index
allows the easy comparison of lake water quality by relating values for water clarity,
phosphorous, and chlorophyll a along a trophic continuum based on a scale of 0 to 100
(Table 4).
Table 4. Summary of Summer Water Quality Parameters and Associated
Values for the Trophic State Index
Secchi Depth ChI -a (ug /L) TP (Ug /L) TSI
Trophic State/ Biological (meter)
Activity
Oligotrophic/Low >4.0 <2.6 <12 <40
Mesotrophic /Moderate 2.0 -4.0 2.6 -6.4 12 -24 40 -50
Eutrophic/High <2.0 >6.4 >24 >50
*Data Source: Carlson, 1977
ChI -a chlorophyll a, TP total phosphorous, and TSI trophic state index
The King County Volunteer Lake Monitoring Program for Steel Lake began in the 1980s,
and has continued through 2001, with a gap froml99l through 1993. The following data
indicate that Steel Lake is relatively low in primary productivity (borderline oligotrophic
to mesotrophic) with very good water quality. No significant trends in water quality were
found based on the data record (A Trend Report on King County Small Lakes, November
2001). See historical TSI values for Steel Lake represented in Table 5.
Table 5. Average Values for Select Trophic Parameters at Steel Lake*
Year Secchi ChI -a TP TSI TSI TSI TSI
Samples (meter) (ug /L) (Ug /L) Secchi Chl a TP Ave
1985 12 3.5 2.6 16 42 40 44 42
1986 11 3.4 3.9 16 43 44 44 44
1987 11 3.4 3.1 15 42 43 43 43
10
STEEL LAKE IAVMP APRIL 3, 2003
L, I aka r_#
1988 1 3.6 3.6 15 42 43 43 42
1989 12 3.0 4.1 18 44 46 46 45
1990 9 2.9 5.0 16 45 44 44 45
1991
1992
1993
1994 12 3.6 4.6 24 42 50 50 46
1995 12 3.7 5.3 19 41 46 46 45
1996 10 3.9 4.2 17 40 45 45 43
1997 12 3.5 3.8 21 42 48 48 44
1998 13 3.4 5.1 13 42 41 41 43
1999 12 3.7 4.3 12 41 40 40 42
2000 8 4.6 3.3 11 38 39 39 40
*Data Source: A Trend Report on King County Small Lakes, November 2001
Chl -a chlorophyll a TP =total phosphorous, and TSI trophic state index
In 2001, Secchi transparency ranged from 1.0 to 6.0m through the year based on both
Level I and Level II records. Water levels rose steadily through winter and dropped
steadily after April. Annual water temperatures ranged from 4.5 to 22.5 degrees Celsius.
Appendix A includes 2001 Secchi Depth graph (Figure 14), 2001 Precipitation/Lake
Level graph (Figure 15), and 2001 Lake Temperature graph (Figure 16).
Phytoplankton made a peak in June 2001, and the population was climbing at the end of
the sampling season. Early populations of the diatom Cyclotella were replaced by the
chrysophyte Dinobryon and the bluegreen Anabaena at peak volume in June 2001. A
variety of taxa were present over the summer, but none made a large population until
October 2001 when another Dinobryon species began to increase rapidly. Chlorophyll
content did not relate closely to the phytoplankton maximum in June 2001 but did show
an increase in October 2001.
Oscillatori sp., a blue -green algae, was found in small quantities in 2000 and 2001.
Moderate blooms of Oscillatori sp. were noted in 2002, and generated a number of
citizen complaints. The City of Federal way responded to these complaints by issuing a
mild health notice to Steel Lake residents concerning the toxic effects of the algae. See
Appendix A for 2001 Phytoplankton and Chlorophyll concentrations (Figures 17,18).
Total phosphorus and total nitrogen remained in proportion to each other through the
sampling period, with the N:P ratio ranging from 23 to 35. In 2001, the TSI indicators
were close together, just above the threshold between oligotrophy and mesotrophy. In
2000, the values were close together, but just below the threshold. Before 2000,
relationships changed between the indicators, but all three values were never close
11
STEEL LAKE IAVMP APRIL 3, 2003
together. See Attachment A for 2001 Total Phosphorous /Total Nitrogen graph (Figure
19).
The primary source of pollutants to Steel Lake is likely stormwater runoff discharged
from 14 outfalls located at various points on the shoreline, in addition to the runoff that
enters the lake directly from shoreline property. Typical pollutants of concern in urban
runoff include; suspended solids, nutrients, bacteria, fertilizers, pesticides and toxic
substances (e.g., metals and polycyclic aromatic hydrocarbons) Elfish (1986).
Eutrophication over time is a process that occurs naturally in some lakes and may be
accelerated in others by human activities. An acceleration of the eutrophication process
may result from normal daily activities that occur in the urban environment. For
example, automobiles and road surfaces contribute metals and petroleum products and
polycyclic aromatic hydrocarbons, gardening, cleaning and other household activities
contribute fertilizers, pesticides, nutrients, and various toxic substances. There is no data
available to determine whether these pollutants exist in Steel Lake, and no current
evidence of toxic effects.
In addition, increases in impervious surfaces associated with land development activities,
also result in increased quantities of surface water runoff flowing to the lake. These
larger surface water flows often carry loads of nutrients and sediments that stimulate plant
growth. This process may result in the overall eutrophication process (A Trend Report on
King County Small Lakes, 2001). The Central Puget Sound basin, which includes the
Steel Lake basin, is 43% impervious cover.
Beneficial and Recreational Uses
Table 6 contains a list of characteristic or beneficial uses that Steel Lake provides to area
residents, visitors, and wildlife. In particular, the lake supports a large city park, excellent
wetland habitat, and a trout stocking program. It is also important to note that no
motorized boats are allowed on the lake.
Table 6. List of Beneficial Uses for Steel Lake
Beneficial Use Location
Swimming Around homes and in City park
Non- motorized Boats Entire Lake
12
STEEL LAKE IAVMP APRIL 3, 2003
FINAL "l
Fishing Whole lake (Fishing derby at park site)
Sailing Whole lake
Waterfowl Habitat Concentrated along western shore
Aesthetic enjoyment In lake and surrounding shoreline
Birdwatching Throughout the lake
Irrigation One water right and three claims exist
Wetland Habitat Near the lake outlet (western end of the lake)
Wildlife Habitat Crayfish, turtles, and frogs primarily near shore
Trout Stocking Deep water habitat (No trout spawn in the lake.)
City park Approximately 700 feet of shoreline
Fish Habitat Spawning (warmwater fish) occurs near docks and lilies in the
west end. No salmon spawn in the lake.
Wildlife
Aquatic noxious weeds (non- native species) can adversely affect the ecological functions
and aesthetics in lakes and streams by crowding out native vegetation and creating single
species stands. Therefore, it is important to recognize the value of native plant species
for fish and wildlife (WDFW, Aquatic Plants and Fish). The fish and wildlife habitat in
Steel Lake will greatly improve by removing non native aquatic plant species (milfoil,
fragrant water lily, yellow flag iris), allowing the native vegetation to thrive.
Steel Lake is managed by the Washington Department of Fish and Wildlife (WDFW) as a
trout and warm -water fishery. Between 1947 and 1969, the lake was rehabilitated on five
occasions by treating with rotenone to reduce populations of spiny -ray fish, and was
stocked each year with approximately 7,000 recently hatched (fry) rainbow trout (Salmo
gairdneri). Due to the mixed species character of the fish community and the poor
survival of trout fry, the fish management program changed in the 1970's by eliminating
rotenone treatments and by stocking with trout of catchable size (i.e. between 8 and 12
inches long) in the spring of each year (Pfeifer 1995 personal communication). During
1985 and 1995, a total of 46,635 trout were allotted for release into Steel Lake. During
this period, surveys identified the presence of the following other fish species: largemouth
r almoides yellow perch Perca ave scens pumpkinseed Le
bass Micro to us s (Lepomis
p p P
P Y p
gibbosus), and brown bullhead (Ictalurus melas).
Since 1991, an average of 6,000 trout were released into the lake each year. In most years,
half of the trout were released directly into the lake during April, prior to opening day of
13
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
the fishing season. The other half were released during June into a pen near the Steel
Lake fishing pier for the opening day fishing derby. Trout not caught in the pen were
released into the lake. WDFW stocked Steel Lake in April of 2002. Stocking included:
4,600 rainbow trout (8 -12 and 650 triploid rainbow trout (sterile, trophy- sized).
On May 13 and 16, 2002, WDFW conducted a survey of Steel Lake•to determine fish
populations, organized by species count and length measurements. WDFW staff used
electro fishing boat, and gull and fyke nets during the survey. Table 7 contains the results
of this survey.
Table 7. Steel Lake Total Fish counts by Species and Length Increments
WDFW Survey 2002
Total 621 148 79 16 37
Sampled
Percent 68.9% 16.4% 8.8% 4.1 1.8%
Species Yellow Largemouth Pumpkin Rainbow Brown
Perch Bass seed Trout Bullhead
Size
(inches)
1-4 4 88 51 0 0
4 -7 415 49 28 0 2
7 -11 202 7 0 37 12
11 -14 0 1 0 0 2
14 -17 0 1 0 0 0
17 -19 0 2 0 0 0
In addition, several red swamp crayfish (Procambarus clarkii) were captured during the
2002 WDFW survey. This exotic, aquatic nuisance species is native to the south central
United States, and was most likely introduced to Steel lake as a result of it's use as live
bait by anglers, or during an aquarium dumping incident. The impact of this introduction
is unknown, but most have had negative consequences (Mueller, WDFW). Red swamp
crayfish are voracious herbivores, and may compete against native crayfish for food
sources, presenting implications for Steel Lake if they multiply dramatically.
Efforts to control red swamp crayfish in Steel Lake will be focused on public education.
Signage, provided by the Department of Ecology, is in place at the public boat launch that
visually identifies the species and warns lake -users of their presence. Lake residents will
also be instructed to destroy the nuisance red swamp crayfish when captured.
14
STEEL LAKE IAVMP APRIL 3, 2003
The Washington Department of Fish and Wildlife (WDFW) conducted a search of the
non -game data system for known occurrences of threatened, endangered, and sensitive
species of animals in the watershed. Bald eagle nests have been sighted adjacent to Puget
Sound, approximately 2 miles west of Steel Lake. In addition, a great blue heron rookery
(breeding area) is present 2.5 miles southeast of the lake. Although these species may
visit Steel Lake no sightings of these or other priority (sensitive) species have been
reported at Steel Lake (Thompson, 1995, pers. comm.). Other priority species that may
visit the lake include the following cavity- nesting ducks: wood duck, Barrow's
goldeneye, common goldeneye, bufflehead, and hooded merganser.
Aquatic Plants and Algae
The aquatic plant community in Steel Lake was surveyed by Metro in 1976, 1978, and
1979; by Resource Management, Inc. (RMI) in 1994 and 1995; by Herrera Environmental
Consultants in 1996 and 1998; by AquaTechnex in 2001 and 2002; and by
in 2003. The relative presence, density, and areal coverage of aquatic
plants from 1976 through 2003 is summarized in Table 8. The scope and methodologies
of each of these surveys were not similar. For example, some surveys were for all aquatic
vegetation and some were only for milfoil and species identification was not consistent.
Caution should be used when comparing the surveys The following are narratives
describing aquatic plant community information and surveys from 1976 to 2003:
1976 1993 Metro Surveys
During this time period, aquatic plants inhabited approximately 27 acres (59 percent) of
the lake (Figures 5 and 6), with submerged macrophytes and macroalgae comprising
approximately 18 acres (67 percent) of the total plant area, and floating- leaved plants
(waterlilies) comprising the remaining 9 acres (33 percent). Comparison of the 1979 and
1994 pre- treatment survey results indicate that although the total area coverage of
submerged macrophytes did not change, the relative density of these plants increased.
Therefore, the plant composition changed to include stands of milfoil. During the same
time period, the area coverage of submerged macroalgae increased, while floating- leaved
plants (waterlilies) decreased. The decrease in waterlilies was primarily due to approved
herbicide (glyphosate) treatments in addition to non chemical controls (i.e. mechanical
harvesting, bottom barriers, and hand cutting) that occurred during this time period.
1994 Survey
Immediately prior to the 1994 Sonar treatment, submerged macrophytes were present
in 7.8 acres of the area currently occupied by Nitella (May 1994, Figure 7). Native
pondweeds (Potamogeton amplifolius and P. pusillus) dominated the submerged
macrophyte community. Eurasian watermilfoil (Myriophyllum spicatum), was present in
15
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
1.3 acres of the lake. Milfoil was not detected during the September 1994 survey (Figure
8
1995 RMI Survey
The RMI survey conducted in May 1995 showed no significant change when compared to
the September 1994 post- treatment survey. Aquatic plants inhabited 35 acres (76 percent)
of the lake, with submerged macroalgae (Nitella sp.) comprising 31.4 acres (90 percent)
of the total plant area. Floating leaved plants, primarily consisting of waterlilies
(Nymphaea odorata and Nuphar lutea spp. variegata), comprised the remaining 3.6 acres
(10 percent).
Waterlily growth was characterized by a large population which grew to a maximum
depth of 5 feet at the west end of the lake. A few small patches of waterlily were also
distributed along the remaining shoreline. Submerged macrophytes such as Large -leaf
pondweed (Potamogeton amplifolius) and thin -leaf pondweed (Potamogeton pusillus)
were present between depths of 5 and 10 feet at densities too sparse to map. Although
they are not shown in the figures, small stands of emergent plants grew along 1,400 feet
(20 percent) of the shoreline, covering a total area of 0.4 acres. Yellow flag iris (Iris
pseudacorus) and cattail (Tvpha sp.) dominated the emergent plant community. Marsh
cinquefoil (Potentilla palustris) and rushes (Juntas sp. and Eleocharis palustris) were
also present (RMI 1994, 1995; Parsons 1995 personal communication).
1996 Herrera Survey
An aquatic plant underwater survey was conducted on July 1 and 2, 1996. The survey
was intended to document the presence, condition, and abundance of aquatic plant species
in Steel Lake (Figure 9). Phytoplankton growth reduced visibility to approximately 10
feet, thus a limited area of the lake was surveyed. This level of effort was considered
adequate by Herrera personnel for the purposes of the evaluation.
Neither milfoil nor other submerged, non native, and invasive aquatic plants were present
in the area surveyed. The composition, distribution, and density of the aquatic plant
community was reported to be similar to that observed prior to the 1994 lake treatment
with Sonar®.
Floating- leafed plants were dominated by fragrant waterlily, and distributed similarly as
was documented in 1994 (at the west end of the lake). The only variation included a
reduction in a small area between transects 49 and 53; and between transects 47 and 49
near the north shore.
Submerged macroalgae dominated the aquatic plant community, and again was similar to
1994 levels. Chara schweinitzii dominated the shallow region (shoreline to 12 feet); and
Nitellaflexilis dominated the deeper region of the lake between 12 and 17 feet. These
populations appear to have been recovering from the 1994 Sonar® treatment, but had not
become dense enough to significantly impair the recreational use of the lake.
16
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
Submerged macrophytes were typically present at relatively low densities (less than 25
percent coverage). Their distribution, density, and diversity appeared to have increased
since t he 1994 but not to nuisance levels. Small- leafed
post-treatment p survey
pondweed, (or thin leafed pondweed), Potamogeton p p pusillus, was the dominant g P
submerged macrophyte reported.
1998 Herrera Survey
An aquatic plant underwater survey was conducted on June 15 and 17, 1998. The survey
was intended to document the presence, condition, and abundance of aquatic plant species
in Steel Lake. Survey methods employed were similar to those used in 1996.
Neither milfoil nor other submerged, non native aquatic plants were present in the area
surveyed. Native species of submerged macrophytes and macroalgae were present in a
healthy condition along each transect from shore to a maximum depth of approximately
15 feet (Figure 10).
Floating- leafed plants were dominated by fragrant waterlily, and distributed similarly as
was documented in the 1998 survey.
Again, as in 1996, Potamogeton pusillus, (small leaved pondweed) was the dominant
submerged macrophyte. Najasfexilis (naiad) was commonly present in shallow waters
less than 8 feet deep. The distribution of naiad was higher in 1998 than in 1996.
Submerged macroalgae dominated the aquatic plant community again in 1998. Chara
schweinitzii dominated the shallow region (less than 8 feet); and Nitellaflexilis
dominated the deeper region of the lake between 12 and 15 feet. These populations were
still not dense enough to significantly impair the recreational use of the lake.
2001 AquaTechnex Survey
This survey, conducted in the summer of 2001 for King County through a grant from the
Department of Ecology, was very limited. Milfoil plants were found along the north
shoreline during the diver survey of the lake (Figure 11). The milfoil colonies were
estimated to be less than 3 acres in size, and at a pioneering level of infestation.
The report stressed the threat posed to other local water bodies, and indicated that the
objective should be eradication of the milfoil. It recommended that an intense survey of
the littoral zone of the lake be conducted in 2002 to detect expansion of the population. In
addition, the report pointed out that Steel Lake would be eligible for a Department of
Ecology Early Infestation Grant, which should be pursued by the appropriate jurisdiction.
A yearly budget of $10,000 was presented that would cover aquatic plant management
efforts if the control program started in 2002. The report warned that it was probable that
the weed would expand dramatically by 2003 if no action were taken, and that a Sonar®
treatment protocol might then be required to remove this plant. The estimated cost for this
approach would be $38,000.
2002 AquaTechnex Survey
17
STEEL LAKE IAVMP APRIL 3, 2003
FINAL T
On August 16, a complete underwater survey was conducted to identify and map all
milfoil plants and their densities. Milfoil was found in several locations throughout the
littoral zone, with the southwest corner exhibiting the largest and most dense (heavy)
colonies. Lesser dense colonies (moderate) were found along the eastern shoreline and in
the bay in the north eastern corner of the lake. Most of the northern shoreline of the lake
contained small patches (sparse) around residential docks (Figure 12).
The size of the milfoil plants ranged from single stems 6 -12 inches long, to multiple
stems 2 -5 feet long originating from a single root crown. Many milfoil plants in the
southwest corner of the lake had reproductive structures (flowers) above the surface of
the water. At the time of the survey, milfoil was estimated to be colonizing
approximately five (5) acres.
The survey indicated the presence of more than 50 milfoil plants. Diver hand removal,
diver dredging and/or application of bottom burlap barriers were deemed to be
impractical for the extent of infestation. AquaTechnex obtained an general NPDES
Noxious Weed Permit to apply the aquatic herbicide 2,4 -D (AquaF.leen®). On August
26, affected areas of Steel Lake was treated with 2,4 -D by spray gun at a rate of 100
pounds per acre.
On August 27 and 30, City of Federal Way Surface Water Management (SWM) staff
collected post treatment lake samples pursuant to the Early Infestation Grant Agreement
with the Department of Ecology. Samples were collected using a Wildco Alpha 2.2 liter
Van Dorn style water bottle. Samples were retrieved from various depths, and combined
into individual composite samples. Samples were analyzed for chlorinated herbicides by
USEPA 8151 GC/MS Modified. Concentrations of 2,4 -D were unexpectedly low.
On September 30, SWM staff inspected the lake to determine the effectiveness of
treatment. Low light conditions prevented an accurate evaluation. On October 4, SWM
staff accompanied AquaTechnex staff, and concluded that there were no surviving milfoil
plants in the treated areas (north, eastern, and western portions) of the lake. The dead
plants were brown in color, stripped of leaves, with only dead stems connected to their
root crowns. No reproductive structures remained above the surface of the water.
2003 Survey
j$41-04, 4y, info in;sgriog
AQUATIC PLANT CHARACTERIZATION
18
STEEL LAKE IAVMP APRIL 3, 2003
F1.-1's. DRAFT
Plant Type Description
Based upon the findings contained in the 2003 Steel Lake Aquatic Plant Survey, the
following includes the characteristics of the dominant species for each type of aquatic
plants: Emergent; Rooted Floating- Leaved Plants; Submerged Macrophytes; and
Submerged Macroalgae. The 2003 Steel Lake aquatic plant survey found three (3) listed
noxious weed species: Eurasian watermilfoil (Myriophyllum spicatum), fragrant water lily
(Nymphaea odorata), and yellow flag iris. These species will be the focus of the plant
management efforts on Steel Lake.
Noxious weeds are legally defined by Washington's Noxious Weed Control Law (RCW
17.10). The term "noxious weed" refers to those non native plants that are highly
destructive, competitive, or difficult to control once established. Noxious weeds have
usually been introduced accidentally as a contaminant or as ornamentals. Non native
plants often do not have natural predators (i.e. herbivores, pathogens) or strong
competitors to control their numbers as they may have had in their home range. WAC
16.750 sets out three classes (A, B, C) of noxious weeds based on their distribution in the
state, each class having different control requirements. County Weed Boards are given
some discretion as to setting control priorities for Class B and C weeds.
Native Plant Species
NATIVE EMERGENT PLANTS
There are no dominant native Emergent Plant types noted in Steel Lake.
NATIVE ROOTED FLOATING LEAVED PLANTS
There are no dominant native Rooted Floating Leaved Plant types noted in Steel Lake.
NATIVE SUBMERGED MACROPHYTES
Small-leafed pondweed (Potamogeton pusillus)
(The following information was obtained in part from the Department of Ecology
website)
Small and leafy pondweeds grow in similar habitats and look alike. They also resemble
other aquatic plants with thin leaves and delicate stems. These pondweeds have long,
narrow leaves and, except for an occasional flower spike that briefly rises above the
water, they remain underwater for their entire lives. Because the narrow leaved
19
STEEL LAKE IAVMP APRIL 3, 2003
PINAL DRAFT
pondweeds look so much alike, close attention must be paid to minute details to
distinguish between them.
The stem is slender and profusely branched, often having with small paired yellowish
glands at the leaf base. The flower appears in 1 -4 whorls on spikes measuring 3 -15 mm
long, not always above the water. The root is fibrous, from the base of the plant, and is
often non rhizomatous. The plant `s seeds and winter buds form at the lateral branch tips
and near the leaf bases. It's seeds and vegetation provide cover and food for aquatic
animals.
Naiads (Naja flexilis)
(The following information was obtained in part from the Department of Ecology
website)
Naiads (or slender water -nymph and common water nymph) are completely submerged
annual plants, although they are often found as floating fragments. They have opposite
leaves that are often clustered near the tips of the stems. The leaf base is much wider than
the rest of the leaf blade, which helps to distinguish the naiads from other underwater
plants. These plants have inconspicuous flowers and fruits that are almost completely
hidden by the leaf bases. Naiad pollination takes place underwater.
The plants have glossy, green, and finely toothed leaves that are oppositely arranged, but
appear to be whorled near ends of the stems. The leaves are long and narrow with broad
bases that clasp the stem, and taper to a long point 1 -3 cm long and 1 -2 mm wide. The
stem is slender, limp and branched up to 2 m long and easily broken. The flower is
inconspicuous, tiny (2 -3 mm), and is located in clusters at the base of the leaves. Male
and female flowers occur separately on the same plant. Naiad pollen is transported by
water currents. The fruit is a small, oval shaped fruit is located in the leaf bases, and are
present in late summer.
The entire plant is eaten by waterfowl. Naiads are considered to be one of their most
important food sources. They also provide shelter for small fish and insects.
NATIVE SUBMERGED MACROALGAE
(The following information was obtained in part from the Department of Ecology
website)
Plant -like algae (Chara, spp)
Although these common lake inhabitants look similar to many underwater plants, they are
actually algae. Chara are green or gray -green colored algae that grow completely
submersed in shallow (4 cm) to deep (20 m) water. Individuals can vary greatly in size,
20
STEEL LAKE IAVMP APRIL 3, 2003
FiNAL DRAFT
ranging from 5 cm to 1 m in length. The main "stem" of Chara bear whorls of branchlets,
clustered at regularly spaced joints. When growing in hard water, Chara sometimes
become coated with lime, giving them a rough gritty feel. These algae are identifiable by
their strong skunk -like or garlic odor, especially evident when crushed.
Algae lack true leaves. Six to 16 leaf-like branchlets of equal length grow in whorls
around the stem, and are never divided. These branchlets often bear tiny thorn -like
projections, which give the plant a rough or prickly appearance when magnified. They
also lack true stems. The round, stem -like structure varies from 5 cm to over 1 m in
length.
Chara, like other algae, do not produce flowers. Instead, microscopic one celled sex
organs called oogonia are formed. These tiny organs and patterns in the cases that
surround them are used to distinguish between species. Tiny spores are produced in
fruiting bodies. In some species the fruiting bodies are orange and very conspicuous. In
addition, Chara may be attached to the bottom by root -like structures called holdfasts.
Plant like algae Nitella, sp.)
Nitellas are bright green algae that often are mistaken for higher plants because they
appear to have leaves and stems. These long, slender, delicate, smooth textured algae lie
on the bottom of a lake or pond and are seldom found in the water column. They are
found growing in shallow to deep waters of soft water or acid lakes and bogs. They often
grow in deeper water than flowering plants and frequently form a thick carpet or grow in
clumps along the bottom.Whorls of forked branches are attached at regularly spaced
intervals along the "stems Nitellas sometime grow together with muskgrasses (Chara
spp.), another plant -like algae, to form underwater meadows.
The plant has no true leaves. Six -eight evenly forked branchlets grow in whorls at
regularly spaced intervals along the "stem Unlike the rough branchlets of most
muskgrasses (Chara spp.), nitella branchlets have a smooth texture.
Nitellas have no true stems, but have hollow, stem -like structures that have whorls of
forked branches alon g g their entire length. The largest nitella species have "stems" up to 2
m long.
The plant does not bear flowers. Instead nitellas have microscopic spore producing
organs. Male organs grow at the base of the branchlets. Female organs are located in a
cluster on the sides of the branchlets below the male organs.
Nitellas produce spores (which are transported by wildlife) rather than fruits, and lack
roots. The plants may be attached to the bottom by root -like structures called holdfasts or
floating free above the sediment.
21
STEEL LAKE IAVMP APRIL 3, 2003
F DRAFT
They provide cover for fish, food for fish and waterfowl, and stabilizes the sediment.
Because nitellas have no roots, they remove nutrients directly from the water. Nitellas are
considered desirable species in Washington.
Non- Native Plant Species
NON- NATIVE EMERGENT PLANTS
Yellow flag iris (Iris pseudacorus)
Yellow flag iris is native to mainland Europe, the British Isles, and the Mediterranean
region of North Africa (Washington State Noxious Weed Control Board, 2001a). This
plant was introduced widely as a garden ornamental. It has also been used for erosion
control. The earliest collection in Washington is from Lake McMurray. in Skagit County
in 1948 (Washington State Noxious Weed Control Board, 2001a). The yellow flowers are
a distinguishing characteristic, and when not flowering it may be confused with cattail
(Typha sp.) or broad fruited bur -reed (Sparganium eurycarpum).
Yellow flag iris is considered an obligate wetland species (OBL), with a >99%
probability of occurring in wetlands as opposed to upland areas (Reed, 1988). The plants
produce large fruit capsules and corky seeds in the late summer. Yellow flag iris spreads
by rhizomes and seeds. Up to several hundred flowering plants may be connected
rhizomatously. Rhizome fragments can form new plants. Yellow flag iris can spread by
rhizome growth to form dense stands that can exclude even the toughest of our native
wetland species, such as Typha latifolia (cattail). In addition to threatening plant
diversity, this noxious weed can also alter hydrologic dynamics through sediment
accretion along the shoreline. This species produces prolific seeds that could easily be
transported downstream to invade other valuable resource areas.
NON NATIVE ROOTED FLOATING- LEAVED PLANTS
Fragrant water lily, white water lily (Nymphaea odorata)
(The following information was obtained in part from the Department of Ecology
website)
Fragrant water lily is a Class C Noxious Weed. Fragrant water lilies (Nymphaea odorata)
are water plants with floating leaves and large many- petaled fragrant blossoms. The
hardy white and (sometimes) pink lilies have become naturalized in Washington lakes
and rivers. These plants are native to the eastern United States and it is believed that the
water lily was introduced to Washington in the late 1800s. Water lilies have been
intentionally planted in many Washington lakes, especially those lakes in western
22
STEEL LAKE IAVMP APRIL 3, 2003
R.A FT
Washington. Lake residents are strongly discouraged from planting fragrant waterlilies in
lakes or natural waterbodies because they are aggressive plants, and sometimes
"hitchhiker" plants such as hydrilla can also be introduced to our lakes when water lilies
are planted. Of 15 lakes surveyed in 1994 in King County, Nymphaea odorata appeared
on the species list of all 15 lakes. Shallow lakes are particularly vulnerable to being
totally covered by fragrant waterlilies.
Left unmanaged, waterlilies will restrict lake -front access and eliminate swimming
opportunities. Requests for waterlily control represent a high percentage of the herbicide
permit requests received by the Department of Ecology. Water lilies grow in dense
patches, excluding native species and even creating stagnant areas with low oxygen levels
underneath the floating mats. These mats make it difficult to fish, water ski, swim, or
even paddle a canoe through. Although relatively slow- spreading, water lilies will
eventually colonize shallow water depths to six feet deep and can dominate the shorelines
of shallow lakes. For this reason, planting water lilies in lakes is not recommended.
Waterlilies provide excellent cover for largemouth bass, sunfish, and frogs. However,
when allowed to grow in dense stands, the floating leaves prevent wind mixing and
extensive areas of low oxygen can develop under waterlily beds during the summer.
When managed to form a patchy distribution interspersed with open water, waterlilies can
provide excellent habitat.
Water lilies reproduce by seed and also by new plants sprouting from the large spreading
roots (underground stems called rhizomes). A planted rhizome will cover about a 15 -foot
diameter in about five years. Each spring (April) new shoots appear from the rhizomes
and row up through the water until they reach the surface. The flowers appear from June
g p g Y Pp
to September. After the flowers have closed for the final time, the flower stalk
"corkscrews" and draws the developing fruit below the water. The plant senesces in the
fall and over winters as the rhizome. Root systems are tenacious, and if pieces of the
rhizome are broken off during control efforts, they will drift to other locations and
establish a new patch of lilies.
Because of their large, showy flowers, water lilies are easy to identify when flowering.
They have white or pink showy flowers. When not in flower look for:
Nearly- circular floating leaves, up -to -11 inches in diameter.
The underside of the leaf is often red or purple with numerous veins.
The stem is attached to the center of the leaf.
The leaves each have a deep cleft to the stem.
NON NATIVE SUBMERGED MACROPHYTES
23
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
(The following information was obtained in part from the Department of Ecology
website)
Eurasian watermilfoil (Myriophyllum spicatum)
Eurasian watermilfoil (milfoil) is a Class B Noxious Weed. Milfoil is an attractive plant
with feathery underwater foliage. Once commonly sold as an aquarium plant, milfoil
originated from Europe and Asia. It was introduced to North America 50 to 100 years
ago. The first known specimen of milfoil in Washington was collected from Lake
Meridian near Seattle in 1965. By the mid 1970s it was also found in Lake Washington.
Now milfoil is found throughout the Northwest; and in western Washington, has followed
the Interstate 5 corridor.
Milfoil is an extremely adaptable plant, able to tolerate and even thrive in a variety of
environmental conditions. It grows in still to flowing waters, grows rooted in water
depths from 1 to 10 meters (regularly reaching the surface while growing in water 3 to 5
meters deep), and can survive under ice. Relative to other submersed plants, milfoil
requires high light, has a high photosynthetic rate, and can grow over a broad temperature
range. Milfoil grows best on fine- textured, inorganic sediments and relatively poorly on
highly organic sediments.
Because it is widely distributed and difficult to control, milfoil is considered to be the
most problematic plant in Washington. The introduction of milfoil can drastically alter a
waterbody's ecology. Milfoil forms very dense mats of vegetation on the surface of the
water. These mats interfere with recreational activities such as swimming, fishing water
skiing, and boating.
The sheer mass of plants can cause flooding and the stagnant mats can create good habitat
for mosquitoes. Milfoil mats can rob oxygen from the water by preventing the wind from
mixing the oxygenated surface waters to deeper water. The dense mats of vegetation can
also increase the sedimentation rate by trapping sediments. Milfoil also starts spring
growth sooner than native aquatic plants and can shade out these beneficial plants. When
milfoil invades new territory, typically the species diversity of aquatic plants
declines. While some species of waterfowl will eat milfoil, it is not considered to be a
good food source.
Milfoil adversely impacts aquatic ecosystems by forming dense canopies that often shade
out native vegetation. Mono specific stands of milfoil provide poor habitat for waterfowl,
fish, and other wildlife. Significant rates of plant sloughing and leaf turnover, as well as
the decomposition of high biomass at the end of the growing season, increase the internal
loading of phosphorus and nitrogen to the water column. Dense milfoil mats alter water
quality by raising pH, decreasing oxygen under the mats, and increasing temperature.
Milfoil exhibits an annual pattern of growth. In the spring, shoots begin to grow rapidly
as water temperatures approach 15 degrees centigrade. When they near the surface, shoots
24
STEEL LAKE IAVMP APRIL 3, 2003
FINAL, DRAFT
branch profusely, forming a dense canopy. The leaves below 1 -meter senesce in response
to self shading. Typically, plants flower upon reaching the surface (usually in mid to late
July). After flowering, plant biomass declines as the result of the fragmentation of stems.
Where flowering occurs early, plant biomass may increase again later in the growing
season and a second flowering may occur. During fall, plants die back to the root crowns,
which sprout again in the spring. In some areas, like western Washington, milfoil
frequently over winters in an evergreen form and may maintain considerable winter
biomass. Milfoil plants do not form specialized over wintering structures such as turions.
Carbohydrate storage occurs throughout over wintering shoots and roots.
Although Milfoil can potentially spread by both sexual and vegetative means, vegetative
spread is considered the major method of reproduction. During the growing season, the
plant undergoes auto fragmentation. The abscising fragments often develop roots at the
nodes before separation from the parent plants. Fragments are also produced by wind and
wave action and boating activities, with each fragment having the potential to develop
into a new plant. Milfoil can easily be transported from lake to lake on boat trailers or
fishing gear. Once introduced, milfoil also may spread rapidly and can infest an entire
lake within two years of introduction to the system.
Some tips to identify milfoil:
Count the pairs of leaflets. Milfoil usually has twelve or more pairs on each leaf.
Milfoil leaves tend to collapse around the stem when removed from the water. Other
milfoil species have thicker stems and are usually more robust.
The mature leaves are typically arranged in whorls of four around the stem.
AQUATIC PLANT CONTROL ALTERNATIVES
The aquatic plant management goals are based on controlling four plant communities:
milfoil, fragrant water lily, native submerged plants, and yellow flag iris. The feasibility
of different plant control techniques depends on the specific aquatic plant and the degree
of control desired.
This section outlines common methods used to control aquatic weeds. Much of the
information in this section is quoted directly from the Department of Ecology's website.
Additional information is derived from the field experience of the King County Noxious
25
STEEL LAKE IAVMP APRIL 3, 2003
Weed Control Program, in particular from Drew Kerr, Aquatic Noxious o Weed Specialist
and WSDA licensed aquatic herbicide applicator. Recommendations found in the 2001
draft version of the "King County Regional Milfoil Plan" have also been taken into
consideration.
Control /eradication methods discussed herein include Aquatic Herbicide, Manual
Methods, Bottom Screens, Diver Dredging, Biological Control, Rotovation, Cutting,
Harvesting, and Drawdown.
Aquatic Herbicides
Description
Aquatic herbicides are chemicals specifically formulated for use in water to eradicate or
control aquatic plants. Herbicides approved for aquatic use by the United States
Environmental Protection Agency (EPA) have been reviewed and considered compatible
with the aquatic environment when used according to label directions. However,
individual states may also impose additional constraints on their use.
Aquatic herbicides are sprayed directly onto floating or emergent aquatic plants, or are
applied to the water in either a liquid or pellet form. Systemic herbicides are capable of
killing the entire plant by tranlocating from foliage or stems and killing the root. Contact
herbicides cause the parts of the plant in contact with the herbicide to die back, leaving
the roots alive and capable of re- growth (chemical mowing). Non selective herbicides
will generally affect all plants that they come in contact with, both monocots and dicots.
Selective herbicides will affect only some plants (usually dicots broad leafed plants like
Eurasian watermilfoil will be affected by selective herbicides whereas monocots like
Brazilian elodea and our native pondweeds may not be affected).
Because of environmental risks from improper application, aquatic herbicide use in
Washington State waters is regulated and has certain restrictions. The Washington State
Department of Agriculture must license aquatic applicators. In addition, because of a
March 2001 court decision (Federal 9 Circuit District Court), coverage under a
discharge permit called a National Pollutant Discharge Elimination System (NPDES)
permit must be obtained before aquatic herbicides can be applied to some waters of the
U.S. This ruling, referred to as the Talent Irrigation District decision, has further defined
Section 402 of the Clean Water Act. Ecology has developed a general NPDES permit
which is available for coverage under the Washington Department of Agriculture for the
management of noxious weeds growing in an aquatic situation and a separate general
permit for nuisance aquatic weeds (native plants) and algae control. For nuisance weeds
(native species also referred to as beneficial vegetation) and algae, applicators and the
local sponsor of the project must obtain a NPDES permit from the Washington
Department of Ecology before applying herbicides to Washington water bodies.
Although there are a number of EPA registered aquatic herbicides, the Department of
Ecology currently issues permits for four aquatic herbicides (as of 2002 treatment
26
STEEL LAKE IAVMP APRIL 3, 2003
FINAL FT
season). Several other herbicides are undergoing review and it is likely that other
chemicals may be approved for use in Washington in the future. As an example, Garlon
3A is due to be approved by the U.S. EPA for aquatic use before spring 2003. The
chemicals that are currently permitted for use in 2002 are:
Rodeo® or Anuamaster® is a systemic non selective herbicide is.used to control
floating- leaved plants like water lilies and shoreline plants like purple loosestrife and
yellow flag iris. It's active ingredient is glyphosate. It is generally applied as a liquid to
the leaves. Rodeo® or Aquamaster® does not work on underwater plants such as
Eurasian watermilfoil. Although glyphosate is a non selective herbicide, a good
applicator can somewhat selectively remove targeted plants by focusing the spray only on
the plants to be, removed. Plants take several weeks to die. A repeat application is often
necessary to remove plants that were missed during the first application. Note: there are
now other glyphosate products available, like Aquamaster with the exact formulation
as Rodeo® but with different trade names now that the patent has expired. Additional
surfactants are often added to improve the penetration of the leaf cuticle and help the
herbicide stay on the plant long enough to be effective. Those that may be used for
emergent weed control include X -77, LI -700, and R -11 as approved by the SEPA process.
2,4 -D is a systemic, selective herbicide used for the control of Eurasian watermilfoil and
other broad leaved species. Formulations of 2,4 -D include:
Navigate® and AquaKleen® Active ingredient 2,4 -D BEE. These granular
products contain the low- volatile butoxyethyl -ester (BEE) formulation of 2,4 -D. 2,4-
D is a relatively fast acting selective, systemic herbicide. It is applied in a granular
formulation and can be effective for sp of treatment of Eurasian watermilfoil. When
used at a rate of 100 pounds per acre, 2,4 -D has shown to be selective to Eurasian
watermilfoil, leaving native aquatic species relatively unaffected.
I
DMA 4IVM Dimethylamine Salt of 2 4 -D. This is a liquid formulation that is
Y q
labeled for aquatic weed control. Since 2,4 -D DMA (like 2,4 -D BEE) is rapidly
converted to 2,4 -D acid, the two products should be equally effective in controlling
Eurasian watermilfoil. Previously, 2,4 -D DMA was only registered for this use in
dams and reservoirs of the Tennessee Valley Authority (TVA) System, but is now
approved for use in Washington. It has recently been used to successfully control
Eurasian watermilfoil in parts of Lake Washington, King County (Dorling, pers.
comm.).
Sonar® Active ingredient fluridone. Sonar® is a slow- acting systemic herbicide
used to control Eurasian watermilfoil and other underwater plants. It may be applied
in pelleted form or as a liquid. Fluridone can show good control of submersed plants
where there is little water movement and an extended time for the treatment. Its use is
most applicable to whole -lake or isolated bay treatments where dilution can be
minimized. It is not effective for spot treatments. It may take six to twelve weeks
before the dying plants fall to the sediment and decompose. When used to manage
Eurasian watermilfoil, Sonar® is applied several times during the summer to maintain
a low, but consistent concentration in the water. Although fluridone is considered to
27
STEEL LAKE IAVMP APRIL 3, 2003
FINAL FT
be a non selective herbicide, when used at low concentrations, it can be used to
selectively remove Eurasian watermilfoil. Some native aquatic plants, especially
pondweeds, are minimally affected by low concentrations of fluridone.
Aquathol® Active ingredient the dipotassium salt of endothall. Aquathol® is a
fast- acting non selective contact herbicide, which destroys the vegetative part of the
plant but does not kill the roots. Aquathol® may be applied in a granular or liquid
form. Generally endothall compounds are used primarily for short -term (one season)
control of a variety of aquatic plants. However, there has been some recent research
that indicates that when used in low concentrations, Aquathol® can be used to
selectively remove exotic weeds, leaving native species unaffected. Because it is fast
acting, Aquathol ID can be used to treat smaller areas effectively. There are water use
restrictions associated with the use of Aquathol ill in Washington.
Advantages
Aquatic herbicide application can be less expensive than other aquatic plant control
methods.
Aquatic herbicides are easily applied around docks and underwater obstructions.
2,4 -D DMA 2,4 -D BEE have been shown to be effective in controlling smaller
infestations (not lake -wide) of Eurasian watermilfoil in Washington.
Washington has had some success in eradicating Eurasian watermilfoil from some
smaller lakes (320 acres or less) using Sonar®.
Disadvantages
Some herbicides have swimming, drinking, fishing, irrigation, and water use
restrictions.
Herbicide use may have unwanted impacts to people who use the water and to the
environment.
Non targeted plants as well as nuisance plants may be controlled or killed by some
herbicides.
Depending on the herbicide used, it may take several days to weeks or several
treatments during a growing season before the herbicide controls or kills treated plants.
Rapid- acting herbicides like Aquathol® may cause low oxygen conditions to develop
as plants decompose. Low oxygen can cause fish kills.
28
STEEL LAKE IAVMP APRIL 3, 2003
MAL T
To be most effective, generally herbicides must be applied to rapidly growing plants.
Some expertise in using herbicides is necessary in order to be successful and to avoid
unwanted impacts.
Many people have strong feelings against using chemicals in water.
Some cities or counties may have policies forbidding or discouraging the use of
aquatic herbicides.
Permit Requirements
A NPDES permit is needed for the use of aquatic herbicides. Both the noxious and
nuisance NPDES permits require the development of integrated aquatic vegetation
management plan by the third year of control work. Monitoring may also be required. For
noxious weed control, apply to the Washington Department of Agriculture for coverage
under their NPDES permit each treatment season. There is no permit or application fee to
obtain coverage under Agriculture's permit.
Costs
Approximate costs for one -acre herbicide treatment (costs will vary from site to site):
pP asY
DMA *4IVM $500 -700
Navigate@ and AquaKleen $500 -700
Rodeo® or Aquamaster® $250
Sonar®: $900 to $1,000
Human Health and Fish and Wildlife Considerations
As far as restrictions for aquatic 2,4 -D applications, there is a 1 -day swimming
restriction, no fishing restriction, and three to five days after treatment the water is
generally below the drinking water standard (70 ppb, irrigation standard is 100 ppb for
broad- leafed plants). There is no irrigation restriction for watering lawns. This chemical
has a low acute toxicity (from an LD50 standpoint, is less toxic than caffeine and slightly
more toxic than aspirin). Based on the low dermal absorption of the chemical, the dose of
the chemical received from skin contact with treated water is not considered significant
(Washington State Dept. of Ecology, 2001b). Recent, state -of -the -art EPA studies
continue to find that it is not considered a carcinogen or mutagen, nor does it cause birth
defects. It has a relatively short persistence in aquatic systems, since it tends to bind to
29
STEEL LAKE IAVMP APRIL 3, 2003
L DRAFT
organic matter in the sediments. The herbicide 2,4 -D generally does not bioaccumulate to
a great extent, and the small amounts which do accumulate are rapidly eliminated once
exposure ceases (Washington State Department of Ecology, 2001 b).
Based on laboratory data reported in the Department of Ecology's Risk Assessment of
2,4 -D, 2,4 -D DMA has a low acute toxicity to fish (LC50 >100 to•524 mg a.i. /L for the
rainbow trout and bluegill sunfish respectively). No Federally sensitive /threatened or
endangered species were tested with 2,4 -D DMA. However, it is likely that endangered
salmonids would not exhibit higher toxic effects to 2,4 -D DMA than those seen in
rainbow trout. Since the maximum use rate of 2,4 -D DMA would be no higher than the
maximum labeled use rate (4.8 mg a.i./L) even the most sensitive fish species within the
biota should not suffer acute impacts from the effects of 2,4 -D DMA. In conclusion, 2,4-
D DMA will not effect fish or free swimming invertebrate biota acutely or chronically
when applied at typical use rates of 1.36 to 4.8 mg a.i./L (Washington State Dept. of
Ecology, 2001b). However, more sensitive species of benthic invertebrates like glass
shrimp may be affected by 2,4 -D DMA, but 80 and 90% of the benthic species should be
safe when exposed to 2,4 -D DMA acutely or chronically at rates recommended on the
label. Field work indicates that 2,4 -D has no significant adverse impacts on fish, free
swimming invertebrates and benthic invertebrates, but well designed field studies are in
short supply.
According to the Department of Ecology's Risk Assessment of 2,4 -D, in the United
States, 2,4 -D BEE is the most common herbicide used to control aquatic weeds. 2,4 -D
BEE, has a high laboratory acute toxicity to fish (LC50 =.0.3 to 5.6 mg a.i./L for rainbow
trout fry and fathead minnow fingerlings, respectively). Formal risk assessment indicates
that short-term exposure to 2,4 -D BEE should cause adverse impact to fish since the risk
quotient is above the acute level of concern of 0.01 (RQ 0.1 ppm/0.3 ppm 0.33).
However, the low solubility rapid of 2 4 -D BEE and its ra id to 2,4 -D acid means
fish are more likely to be exposed to the much less toxic 2,4 -D acid. 2,4 -D acid has a
toxicity similar to 2,4 -D DMA to fish (LC50 20 mg to 358 mg a.i./L for the common
carp and rainbow trout, respectively). In contrast, formal risk assessment with 2,4 -D acid
indicates that short-term exposure to 2,4 -D BEE should not cause adverse impact to fish
since the risk quotient is below the federal level of concern of 0.01 (RQ 0.1 ppm/20
ppm 0.005). To conclude, 2,4 -D BEE will have no significant impact on the animal
biota acutely or chronically when using applied rates recommended on the label
(Washington State Dept. of Ecology, 2001b). Although laboratory data indicates that 2,4-
D BEE may be toxic to fish, free swimming invertebrates and benthic invertebrates, data
indicates that its toxic potential is not realized under typical concentrations and
conditions found in the field. This lack of field toxicity is likely due to the low solubility
of 2,4 -D BEE and its rapid hydrolysis to the practically non -toxic 2,4 -D acid within a few
hours to a day following the application.
Glyphosate is practically nontoxic by ingestion, with a reported acute oral LD50 of 5600
mg/kg in the rat. Technically, glyphosate acid is practically nontoxic to fish and may be
slightly toxic to aquatic invertebrates (EXTOXNET, 1996). Some formulations may be
30
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
more toxic to fish and aquatic species due to differences in toxicity between the salts and
the parent acid, or to surfactants used in the formulation. There is a very low potential for
the compound to build up in the tissues of aquatic invertebrates or other aquatic
organisms. Glyphosate is moderately persistent in soil, with an estimated average half -life
of 47 days. It is strongly adsorbed to most soils, even those with lower organic and clay
content. Thus, even though it is highly soluble in water, field and laboratory studies show
it does not leach appreciably, and has low potential for runoff (except as adsorbed to
colloidal matter). One estimate indicated that less than 2% of the applied chemical is lost
to runoff. Microbes are primarily responsible for the breakdown of the product, and
volatilization or photodegradation losses will be negligible. In water, glyphosate is
strongly adsorbed to suspended organic and mineral matter and is broken down primarily
by microorganisms.
Suitability for Steel Lake
Aquatic herbicides can provide an effective method for control and eventual eradication
of noxious weeds. The use of a formulation of 2,4 -D should provide excellent initial
control of Eurasian watermilfoil while allowing for the more appropriate spot treatments
for future scattered infestation. Annual surveys, public education, effective and spot
treatments as necessary will be sufficient to control and eradicate milfoil. Therefore, the
potential for future lake -wide fluridone treatments with fluridone (Sonar®) will be
reduced substantially.
The granular formulations of 2,4 -D BEE found in Navigate® and AquaKleen® has been
shown to be highly effective for spot treatment of milfoil in Steel Lake. The time released
nature of these granular formulations is less susceptible to drift. Liquid formulations can
drift off target as a result of wind and/or boat activity. Therefore, liquid formulations have
a slightly higher risk of injuring off target organisms. In addition, granular applications
are visible the applicator can direct the product directly onto the target plants. The
granules adhere to the leaves, increasing the effectiveness (Vandermeulen, personal
communication). However, impacts to resident fish populations in the short term would
be greatest with the use of 2,4 -D BEE as it has a high acute toxicity before its hydrolysis
to 2,4 -D acid.
Steel Lake does not appear to have anadromous salmonids. According to King County's
Hylebos and Lower Puget Sound Basin Plan, salmon habitat potentially exists on the
lower reach of Redondo Creek into Federal Way. However, the stream is likely blocked
to salmon migration due to a culvert at the mouth of the stream where the lower most 500
feet of the channel is piped, and likely presenting an impassable barrier to migrating fish.
(Hylebos Creek and Lower Puget Sound Basins Current and Future Conditions Report).
Therefore, the choice of treatment methodologies is not limited by the presence of
anadromous salmonids.
Glyphosate should be very effective on the other target species: fragrant water lily, and
yellow flag iris. Westerdahl and Getsinger (1988) report excellent control of the fragrant
31
STEEL LAKE IAVMP APRIL 3, 2003
i w FT RA
water lily with glyphosate. glyphosate is the recommended herbicide for water
Generally
control because it can be applied directly to the floating leaves, unlike fluridone or
endothall which must be applied to the water. The application of glyphosate allows
specific plants or areas of plants to be targeted for removal. Generally two applications of
glyphosate are needed. The second application later in the summer controls the plants that
were missed during the first herbicide application. The control effectiveness of fragrant
water lily is easy to measure through visual surveys due to the floating leaves.
Glyphosate should also provide excellent systemic control of yellow flag iris. This
species has an abundant leaf surface area to absorb the chemical for translocation to the
rhizome. The use of an herbicide will enable the elimination of the mature plants without
potentially destructive disturbance of the shoreline by excavation.
One of the main reasons to eradicate milfoil and fragrant water lily is to maintain the
health of the native aquatic plant community for all of the species that utilize them in
their life cycles, as well as for the human recreational uses. The nature of the control
methods to be implemented will minimize impacts to native aquatic vegetation. The
control of the Eurasian watermilfoil and fragrant water lily will be conducted by methods
designed to preserve (and eventually enhance or conserve) the native plant communities.
Herbicide selective to Eurasian watermilfoil will be used for its control and should not
require a whole -lake treatment that would expose all the submersed plants to the
herbicide. The herbicide for the fragrant water lily will be applied to the leaves, and
therefore should be easily focused to kill only the target vegetation.
The application of herbicide to the emergent species (yellow flag iris) will also be
conducted by manual spot applications. An experienced herbicide applicator can
selectively target individual weed species and limit collateral damage to other species to a
minimum. This is especially true when infestations are small so that large areas with a
diverse plant distribution don't have to be treated. Since the emergent noxious weed
infestations at Steel Lake are still confined largely to the shoreline, it should be relatively
simple for the control applicator to avoid collateral damage and preserve the native plant
community.
The need to revegetate after controlling the milfoil and fragrant water lily is unknown at
this time. It is anticipated that removal of the invasive vegetation will promote growth of
native plants. The goal is to have at least 40% native aquatic vegetative cover. The
annual survey will help determine whether there is sufficient native vegetation to support
aquatic wildlife. In the terrestrial environment, bare ground will often be colonized
rapidly by invasive species, but this is not usually a problem in lacustrine areas.
A drawback of using herbicides is the "uplifting" of mats of decomposing water lily roots
that can form large floating islands in the waterbody after the herbicides have killed the
plants. These floating mats may become problematic, especially at the west end of the
lake where a larger area is covered with fragrant water lily. Often these large islands float
to the east end of the lake landing on the shoreline.
32
STEEL LAKE IAVMP APRIL 3, 2003
x... 1
Manual Methods
Hand Pulling
g aquatic Hand ulli a uatic plants is similar to pulling weeds out of a garden. It involves
p
removing entire plants (leaves, stems, and roots) from the area of concern and disposing
of them in an area away from the shoreline. In water less than three feet deep no
Y P
specialized equipment is required, although a spade, trowel, or long knife may be needed
if the sediment is packed or heavy. In deeper water, hand- pulling is best accomplished by
divers with SCUBA equipment and mesh bags for the collection of plant fragments.
Some sites may not be suitable for hand pulling such as areas where deep flocculent
sediments may cause a person hand pulling to sink deeply into the sediment.
Cutting
s
Cutting differs from hand pulling in that plants are cut an d the root are not removed.
Cutting is performed by standing on a dock or on shore and throwing a cutting tool out
into the water. A non-mechanical aquatic weed cutter is commercially available. Two
single- sided, razor sharp stainless steel blades forming a "V" shape are connected to a
handle, which is tied to a long rope. The cutter can be thrown about 20 30 feet into the
water. As the cutter is pulled through the water, it cuts a 48 -inch wide swath. Cut plants
rise to the surface where they can be removed. Washington State requires that cut plants
be removed from the water. The stainless steel blades that form the V are extremely sharp
and great care must be taken with this implement. It should be stored in a secure area
where children do not have access.
Raking
A sturdy rake makes a useful tool for removing aquatic plants. Attaching a rope to the
rake allows removal of a greater area of weeds. Raking literally tears plants from the
sediment, breaking some plants off and removing some roots as well. Specially designed
aquatic plant rakes are available. Rakes can be equipped with floats to allow easier plant
and fragment collection. The operator should pull towards the shore because a substantial
amount of plant material can be collected in a short distance.
Cleanup
All of the manual control methods create plant fragments. It's important to remove all
fragments from the water to prevent them from re- rooting or drifting onshore. Plants and
fragments can be composted or added directly to a garden.
Advantages
33
STEEL LAKE IAVMP APRIL 3, 2003
Manual methods are easy to use around docks and swimming areas.
The equipment is inexpensive.
Hand pulling allows the flexibility to remove undesirable aquatic plants while leaving
desirable plants.
These methods are environmentally safe and will not harm aquatic wildlife.
Manual methods don't require expensive permits, and can be performed on aquatic
noxious weeds with Hydraulic Project Approval obtained by reading and following
the pamphlet Aquatic Plants and Fish (publication #APF -1 -98) available from the
Washington Department of Fish Wildlife.
Disadvantages
As plants re -grow or fragments re- colonize the cleared area, the treatment may need
to be repeated several times each summer.
Because these methods are labor intensive, they may not be practical for large areas
or for thick weed beds.
Even with the best containment efforts, it is difficult to collect all plant fragments,
leading to re- colonization.
Some plants, like water lilies which have massive rhizomes, are difficult to remove by
hand pulling.
Pulling weeds and raking stirs up the sediment and making it difficult to see
remaining plants.
Sediment re- suspension can also increase nutrient levels in lake water. Hand pulling
and raking impacts bottom dwelling animals.
The V- shaped cutting tool is extremely sharp and can be dangerous to use.
Permit Requirements
Permits are required for many types of manual projects in lakes and streams. The
Washington State Department of Fish and Wildlife requires a Hydraulic Project Approval
permit for all activities taking place in the water including hand pulling, raking, and
cutting of aquatic plants. In addition, some projects may require a Shoreline Development
permit from the City of Federal Way.
Costs
Hand pulling costs up to $130 for the average waterfront lot for a hired commercial
puller.
34
STEEL LAKE IAVMP APRIL 3, 2003
A commercial grade weed cutter costs about $130 with accessories. A commercial
rake costs about $95 to $125.
A homemade weed rake costs about $85 (asphalt rake is about $75 and the rope costs
35 -75 cents per foot).
Other Considerations
Manual methods must include regular scheduled surveys to determine the extent of
the remaining weeds and /or the appearance of new plants after eradication has been
attained.
Manual methods have the potential for missing milfoil plants, especially after stirring
up sediments.
Manual methods have the potential for fragmentation, exacerbating the existing
milfoil problem
Suitability for Steel Lake
Annual diver hand- pulling should be sufficient to remove a portion of re- emerging
milfoil plants. In combination with herbicide treatments (when needed), manual
methods used to contain and control, can effectively combat milfoil re- infestations in
subsequent years.
Cutting can be used to control small areas of fragrant water lily, especially those close
to the shoreline. Using this method out in the open water would require a stable boat
(not canoe) and great care not to injure oneself or another passenger. Since repeated
cutting over several seasons may be required to starve the roots, this would fit best as
a supplement to other control methods.
Manual efforts are much more difficult on yellow flag iris since the plants don't
emerge from simple stems that can be cut, and they arise from massive rhizomes
inhibiting pulling or digging. The growth area may also be dangerous for volunteers
or homeowners due to the deep muck along the lakeshore.
Because there is a large amount of root mass associated with the iris, a significant
effort is necessary to remove by excavation, an activity that may potentially disturb
other plant communities. This would also expose the face of the peat layer, which
could contribute to desiccation and disintegration of the other beneficial plant colony
edges. This could lead to water quality problems.
Diver Dredging
Diver dredging (suction dredging) is a method whereby SCUBA divers use hoses
attached to small dredges (often dredges used by miners for mining gold from streams) to
35
STEEL LAKE IAVMP APRIL 3, 2003
suck plant material from the sediment. The purpose of diver dredging is to remove all
parts of the plant including the roots. A good operator can accurately remove target
plants, like Eurasian watermilfoil, while leaving native species untouched. The suction
hose pumps the plant material and the sediments to the surface where they are deposited
into a screened basket. The water and sediment are returned back to the water column (if
the permit allows this), and the plant material is retained. The turbid water is generally
discharged to an area curtained off from the rest of the lake by a silt curtain. The plants
are disposed of on shore. Removal rates vary from approximately 0.25 acres per day to
one acre per day depending on plant density, sediment type, and diver efficiency. Diver
dredging is more effective in areas where softer sediment allows easy removal of the
entire plants, although water turbidity is increased with softer sediments. Harder sediment
may require the use of a knife or tool to help loosen sediment from around the roots. In
very hard sediments, milfoil plants tend to break off leaving the roots behind and
defeating the purpose of diver dredging.
In a large -scale operation in western Washington, two years of diver dredging reduced the
population of milfoil by 80 percent (Silver Lake, Everett). Diver dredging is less effective
on plants where seeds, turions, or tubers remain in the sediments t� sprout the next
growing season. For that reason, Eurasian watermilfoil is generally the target plant for
removal during diver dredging operations.
Advantages
Diver dredging can be a very selective technique for removing pioneer colonies of
Eurasian watermilfoil.
Divers can remove plants around docks and in other difficult to reach areas.
Diver dredging can be used in situations where herbicide use is not an option for
aquatic plant management.
Disadvantages
Diver dredging is very expensive.
Dredging stirs up large amounts of sediment. This may lead to the release of nutrients
or long -buried toxic materials into the water column.
Only the tops of plants growing in rocky or hard sediments may be removed, leaving a
viable root crown behind to initiate growth.
Acquisition of permits may take more than a year.
Permit Requirements
Permits are required for many types of projects in lakes and streams. Diver dredging
requires Hydraulic Approval from the Department of Fish and Wildlife and a Temporary
Modification of Water Quality Standards from Ecology. The city and county must be
reviewed for any local requirements before proceeding with a diver dredging project.
36
STEEL LAKE IAVMP APRIL 3, 2003
Also diver dredging may require a Section 404 permit from the U.S. Army Corps of
Engineers.
Costs
Depending on the density of the plants, specific equipment used, and disposal
requirements, costs can range from a minimum of $1,500 to $2,000 per day.
Other Considerations
Might be good spot control method in subsequent years (coordinated with diver
survey)
Suitability for Steel Lake
As with diver hand pulling, diver dredging could be used after the initial herbicide
applications to remove plants that were missed or unaffected by the herbicide. However,
permit costs may warrant having this work done as diver hand pulling since the roots
should be largely removed from the loose sediments without the need for dredging.
Diver dredging greatly disturbs sediments and can affect nutrient concentrations and algal
production in the lake (see Disadvantages above). If other removal techniques are
suitable, diver dredging should not be considered.
Bottom Barriers
A bottom screen or benthic barrier covers the sediment like a blanket, compressing
aquatic plants while reducing or blocking light. Materials such as burlap, plastics,
perforated black Mylar, and woven synthetics can all be used as bottom screens. Some
people report success using pond liner materials. There is also a commercial bottom
screen fabric called Texel, a heavy, felt -like polyester material, which is specifically
designed for aquatic plant control.
An ideal bottom screen should be durable, heavier than water; reduce or block light,
prevent plants from growing into and under the fabric, be easy to install and maintain, and
should readily allow gases produced by rotting weeds to escape without "ballooning" the
fabric upwards.
Even the most porous materials, such as window screen will billow due to gas buildup.
Therefore, it is very important to anchor the bottom barrier securely to the bottom.
Unsecured screens can create navigation hazards and are dangerous to swimmers.
Anchors must be effective in keeping the material down and must be regularly checked.
Natural materials such as rocks or sandbags are preferred as anchors.
The duration of weed control depends on the rate that weeds can grow through or on top
of the bottom screen, the rate that new sediment is deposited on the barrier, and the
durability and longevity of the material. For example, burlap may rot within two years,
37
STEEL LAKE IAVMP APRIL 3, 2003
Ft AFT
plants can grow through window screening material, and can grow on top of felt -like
Texel fabric. Regular maintenance is essential and can extend the life of most bottom
barriers.
Bottom screens will control most aquatic plants, however freely- floating species will not
be controlled by bottom screens. Plants like Eurasian watermilfoil will send out lateral
surface shoots and may canopy over the area that has been screened giving less than
adequate control.
In addition to controlling nuisance weeds around docks and in swimming beaches,
bottom screening has become an important tool to help eradicate and contain early
infestations of noxious weeds such as Eurasian watermilfoil and Brazilian elodea.
Pioneering colonies that are too extensive to be hand pulled can sometimes be covered
with bottom screening material. For these projects, burlap with rocks or burlap sandbags
can be used for anchors. By the time the material decomposes, the milfoil patches will be
dead as lon g as all plants were completely covered. Snohomish County staff reported
native aquatic plants colonizing burlap areas that covered pioneering patches of Eurasian
watermilfoil. When using this technique for Eurasian watermilfoil eradication projects,
divers should recheck the screen within a few weeks to make sure that all milfoil plants
remain covered and that no new fragments have taken root nearby.
Bottom screens can be installed by the homeowner or by a commercial plant control
specialist. Installation is easier in winter or early spring when plants have died back. In
summer, cutting or hand pulling the plants first will facilitate bottom screen installation.
Research has shown that much more gas is produced under bottom screens that are
installed over the top of aquatic plants. The less plant material that is present before
installing the screen, the more successful the screen will be in staying in place. Bottom
screens may also be attached to frames rather than placed directly onto the sediment. The
frames may then be moved for control of a larger area.
Advantages
Installation of a bottom screen creates an immediate open area of water.
Bottom screens are easily installed around docks and in swimming areas.
Properly installed bottom screens can control up to 100 percent of aquatic plants.
Screen materials are readily available and can be installed by homeowners or by
divers.
Disadvantages
Because bottom screens reduce habitat by covering the sediment, they are suitable
only for localized control.
38
STEEL LAKE IAVMP APRIL 3, 2003
For safety and performance reasons, bottom screens must be regularly inspected and
maintained.
Harvesters, rotovators, fishing gear, propeller backwash, or boat anchors may damage
or dislodge bottom screens.
Improperly anchored bottom screens may create safety hazards for boaters and
swimmers.
Swimmers may be injured by poorly maintained anchors used to pin bottom screens
to the sediment.
Some bottom screens are difficult to anchor on deep muck sediments.
Bottom screens interfere with fish spawning and bottom dwelling animals.
Without regular maintenance aquatic plants may quickly colonize the bottom screen.
Permit Requirements
Bottom screening in Washington requires hydraulic approval, obtained free from the
Department of Fish and Wildlife. Check with your local jurisdiction to determine whether
a shoreline permit is required.
Costs
Barrier materials cost $0.22 to $1.25 per square foot. The cost of some commercial
barriers includes an installation fee.
Commercial installation costs vary depending on sediment characteristics and type of
to have 1 000 square feet of bottom
bottom screen selected. It costs up to about $750 0
p q
year.
each 120 front lot are about ter
screen installed. Maintenance costs for a waterfront y
Other Considerations
None
Suitability for Steel Lake
Infested areas are too scattered or are too large to use a bottom barrier without
becoming cost prohibitive.
Barriers could be effective in dense milfoil areas that have shown resistance to 2,4 -D
herbicide applications.
Barriers could be used to eradicate localized infestations.
39
STEEL LAKE IAVMP APRIL 3, 2003
Biological Control
General Overview
Many problematic aquatic plants in the western United States are non indigenous species.
Plants like Eurasian watermilfoil have been introduced to North America from other
continents. Here they grow extremely aggressively, forming monocultures that exclude
native aquatic plants and degrade fish and wildlife habitat. Yet, often these same species
are not aggressive or invasive in their native range. This may be in part because their
populations are kept under control by insects, diseases, or other factors not found in areas
new to them.
The biological control of aquatic plants focuses on the selection and introduction of other
organisms that have an impact on the growth or reproduction of a target plant, usually
from their native ranges. Theoretically, by stocking an infested waterbody or wetland with
these organisms, the target plant can be controlled and native plants can recover.
Classic biological control uses control agents that are host specific..These organisms
attack only the species targeted for control. Generally these biocontrol agents are found in
the native range of the nuisance aquatic plants and, like the targeted plant, these
biocontrol agents are also non indigenous species. With classic biological control an
exotic species is introduced to control another exotic species. However, extensive
research must be conducted before release to ensure that biological control agents are host
specific and will not harm the environment in other ways. The authors of Biological
Control of Weeds A World Catalogue of Agents and Their Target Weeds state that after
100 years of using biocontrol agents, there are only eight examples, world -wide, of
damage to non target plants, "none of which has caused serious economic or
environmental damage..."
Search for a classical biological control agent typically starts in the region of the world
that is home to the nuisance aquatic plant. Researchers collect and rear insects and/or
pathogens that appear to have an impact on the growth or reproduction of the target
species. Those insects /pathogens that appear to be generalists (feeding or impacting other
aquatic plant species) are rejected as biological control agents. Insects that impact the
target species (or very closely related species) exclusively are considered for release.
Once collected, these insects are reared and tested for host specificity and other
parameters. Only extensively researched, host specific organisms are cleared by the
United States for release. It generally takes a number of years of study and specific testing
before a biological control agent is approved.
Even with an approved host specific bio- control agent, control can be difficult to achieve.
Some biological control organisms are very successful in controlling exotic species and
others are of little value. A number of factors come into play. It is sometimes difficult to
establish reproducing populations of a bio- control agent. The ease of collection of the
bio- control and placement on the target species can also have a role in the effectiveness.
Climate or other factors may prevent its establishment, with some species not proving
capable of over wintering in their new setting. Sometimes the bio- control insects become
40
STEEL LAKE IAVMP APRIL 3, 2003
i
et
prey for native predator species, and sometimes the impact of the insect on the target
plant just isn't enough to control the growth and reproduction of the species.
People who work in this field say that the more biological control species that you can put
to work on a problem plant, the better success you will have in controlling the targeted
species. There are some good examples where numerous biological control agents have
had little effect on a targeted species, and other examples where one bio- control agent
was responsible for the complete control of a problem species.
However, even when biological control works, a classic biological control agent generally
does not totally eliminate all target plants. A predator -prey cycle establishes where
increasing predator populations will reduce the targeted species. In response to decreased
food supply (the target plant is the sole food source for the predator), the predator species
will decline. The target plant species rebounds due to the decline of the predator species.
The cycle continues with the predator populations building in response to an increased
food supply.
Although a successful biological control agent rarely eradicates a problem species, it can
reduce populations substantially, allowing native species to return. Used in an integrated
approach with other control techniques, biological agents can stress target plants making
them more susceptible to other control methods.
A number of exotic aquatic species have approved classic biological control agents
available for release in the US. Theses
water hyacinth, alligator
species include Hydrilla, wa h
g
p Y Y
weed, and purple loosestrife.
Another type of biological control uses general agents such as grass carp (see below) to
manage problem plants. Unlike classical bio- control agents, these fish are not host
specific and will not target specific species. Although grass carp do have food
preferences, under some circumstances, they can eliminate all submersed vegetation in a
waterbody. Like classic biological control agents, grass carp are exotic species and
originate from Asia. In Washington, all grass carp must be certified sterile before they can
be imported into the state. There are many waterbodies in Washington (mostly smaller
sites) where grass carp are being used to control the growth of aquatic plants.
During the past decade a third type of control agent has emerged. In this case, a native
insect that feeds and reproduces on northern milfoil (Myriophyllum sibericum) which is
native to North America, was found to also utilize the non native Eurasian watermilfoil
(Myriophyllum spicatum). Vermont government scientists first noticed that Eurasian
watermilfoil had declined in some lakes and brought this to the attention of researchers. It
was discovered that a native watermilfoil weevil (Euhrychiopsis lecontei) feeding on
Eurasian watermilfoil caused the stems to collapse. Because native milfoil has thicker
stems than Eurasian watermilfoil, the mining activity of the larvae does not cause it the
same kind of damage. A number of declines of Eurasian watermilfoil have been
documented around the United States and researchers believe that weevils may be
implicated in many of these declines.
41
STEEL LAKE IAVMP APRIL 3, 2003
P,I7JrAL
Several researchers around the United States (Vermont, Minnesota, Wisconsin, Ohio,
Washington) have been working to determine the suitability of this insect as a bio- control
agent. The University of Washington is conducting research into the suitability of the
milfoil weevil for the biological control of milfoil in Washington lakes and rivers.
Surveys have shown that in Washington the weevil is found more often in eastern
Washington lakes and it seems to prefer more alkaline waters. However, it is also present
in cooler, wetter western Washington. The most likely candidates for use as biological
controls are discussed in the following section.
Grass Carp
The grass carp (Cteno pharynogodon), also known as the white amur, is a vegetarian fish
native to the Amur River in Asia. Because this fish feeds on aquatic plants, it can be used
as a biological tool to control nuisance aquatic plant growth. In some situations, sterile
(triploid) grass carp may be permitted for introduction into Washington waters.
Permits are most readily obtained if the lake or pond is privately owned, has no inlet or
outlet, and is fairly small. The objective of using grass carp to control aquatic plant
growth is to end up with a lake that has about 20 to 40 percent plant cover, not a lake
devoid of plants. In practice, grass carp often fail to control the plants, or in cases of
overstocking, all the submersed plants are eliminated from the waterbody.
The Washington Department of Fish and Wildlife determines the appropriate stocking
rate for each waterbody when they issue the grass carp- stocking permit. Stocking rates for
Washington lakes generally range from 9 to 25 eight- to eleven -inch fish per vegetated
acre. This number will depend on the amount and type of plants in the lake as well as
spring and summer water temperatures. To prevent stocked grass carp from migrating out
of the lake and into streams and rivers, all inlets and outlets to the pond or lake must be
screened. For this reason, residents on waterbodies that support a salmon or steelhead run
are rarely allowed to stock grass carp into these systems.
Once grass carp are stocked in a lake, it may take from two to five years for them to
control nuisance plants. Survival rates of the fish will vary depending on factors like
presence of otters, birds of prey, or fish disease. A lake will probably need restocking
about every ten years.
Success with grass carp in Washington has been varied. Sometimes the same stocking
rate results in no control, control, or even complete elimination of all underwater plants.
Bonar et. Al. Found that only 18 percent of 98 Washington lakes stocked with grass carp
at a median level of 24 fish per vegetated acre had aquatic plants controlled to an
intermediate level. In 39 percent of the lakes, all submersed plant species were eradicated.
It has become the consensus among researchers and aquatic plant managers around the
country that grass carp are an all or nothing control option. They should be stocked only
in waterbodies where complete elimination of all submersed plant species can be
tolerated.
42
STEEL LAKE IAVMP APRIL 3, 2003
"7 tea
Grass carp exhibit definite food preferences and some aquatic plant species will be
consumed more readily than others. Pauley and Bonar performed experiments to evaluate
the importance of 20 Pacific Northwest aquatic plant species as food items for grass carp.
Grass carp did not remove plants in a preferred species -by- species sequence in multi
species plant communities. Instead they grazed simultaneously on palatable plants of
similar preference before gradually switching to less preferred groups of plants. The
relative preference of many plants was dependent upon what other plants were associated
with them. The relative preference rank for the 20 aquatic plants tested was as follows:
Potamogeton crispus (curly leaf pondweed) P. pectinatus (sago pondweed) P.
zosteriformes (flat- stemmed pondweed) Chara sp.(muskgrasses) Elodea canadensis
(American waterweed) thin leaved pondweeds Potamogeton spp. Egeria densa
(Brazilian elodea) (large fish only) P. praelongus (white- stemmed pondweed)
Vallisneria americana (water celery) Myriophyllum spicatum (Eurasian watermilfoil)
Ceratophyllum demersum (coontail) >Utricularia vulgaris (bladderwort) Polygonum
amphibium (water smartweed) P. natans (floating leaved pondweed) P. amplifolius
(big leaf pondweed) Brasenia schreberi (watershield) Juncus sp.(rush) Egeria
densa (Brazilian elodea) (fingerling fish only) Nymphaea sp. (fragrant water lily)
Typha sp. (cattail) Nuphar sp. spatterdock).
Generally in Washington, grass carp do not consume emergent wetland vegetation or
water lilies even when the waterbody is heavily stocked or over stocked. A heavy
stocking rate of triploid grass carp in Chambers Lake, Thurston County resulted in the
loss of most submersed species, whereas the fragrant water lilies, bog bean, and
spatterdock remained at pre- stocking levels. A stocking of 83,000 triploid grass carp into
Silver Lake Washington resulted in the total eradication of all submersed species,
including Eurasian watermilfoil, Brazilian elodea, and swollen bladderwort. However, the
extensive wetlands surrounding Silver Lake have generally remained intact. In southern
states, grass carp have been shown to consume some emergent vegetation (Washington
State Department of Ecology, 2002).
Grass carp stocked into Washington lakes must be certified disease free and sterile.
Sterile fish, called triploids because they have an extra chromosome, are created when the
fish eggs are subjected to a temperature or pressure shock. Fish are verified sterile by
collecting and testing a blood sample. Triploid fish have slightly larger blood cells and
can be differentiated from diploid (fertile) fish by this characteristic. Grass carp imported
into Washington must be tested to ensure that they are sterile.
Because Washington does not allow fertile fish within the state, all grass carp are
imported into Washington from out of state locations. Most grass carp farms are located
in the southern United States where warmer weather allows for fast fish growth rates.
Large shipments are transported in special trucks and small shipments arrive via air.
Some facts about grass carp:
Are only distantly related to the undesirable European carp, and share few of its
habits.
43
STEEL LAKE IAVMP APRIL 3, 2003
Generally ive for at least ten years and possibly much longer in Washington State
Y Y P Y g
waters.
Will grow rapidly and reach at least ten pounds. They have been known to reach 40
pounds in the southern United States.
I
Feed only on plants at the age they are stocked into Washington waters.
Will not eat fish eggs, young fish or invertebrates, although baby grass carp are
omnivorous.
Feed from the top of the plant down so that mud is not stirred up. However, in ponds
and lakes where grass carp have eliminated all submersed vegetation the water
becomes turbid. Hungry fish will eat organic material out of the sediments.
Have definite taste preferences. Plants like Eurasian milfoil and coontail are not
preferred. American waterweed and thin leaved pondweeds are preferred. Water lilies
are rarely consumed in Washington waters.
Are dormant during the winter. Intensive feeding starts when water temperatures
reach 68 F.
Prefer flowing water to still waters (original habitat is fluvial).
Are difficult to recapture once released.
They may not feed in swimming areas, docks, boating areas, or other sites where there
is heavy human activity.
Advantages
Grass carp are inexpensive compared to some other control methods and offer long-
term control, but fish may need to be restocked at intervals.
Grass carp offer a biological alternative to aquatic plant control.
Disadvantages
Depending on plant densities and types, it may take several years to achieve plant
control using grass carp and in many cases control may not occur.
If the waterbody is overstocked, all submersed aquatic plants may be eliminated.
Removing excess fish is difficult and expensive.
The type of plants grass carp prefer may also be those most important for habitat and
for waterfowl food.
If not enough fish are stocked, less favored plants, such as Eurasian milfoil, may take
over the lake.
Stocking grass carp may lead to algae blooms.
44
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
All inlets and outlets to the lake or pond must be screened to prevent grass carp from
escaping into streams, rivers, or other lakes.
Permit Requirements
Stocking grass carp requires a fish- stocking permit from the Washington Department of
Fish and Wildlife. Also, if inlets or outlets need to be screened, an Hydraulic Project
Approval application must be completed for the screening project.
Costs
In quantities of 10,000 or more, 8 to 12 inch sterile grass carp can be purchased for about
$5.00 each for truck delivery. The cost of small air freighted orders will vary and is
estimated at $8 to $10 per fish.
The costs for researchers to locate, culture, and test bio- control agents is high. Once
approved for use, insects can sell for $1.00 or more per insect. Sometimes it is possible to
establish nurseries where weed specialists can collect insects for reestablishment
elsewhere.
Other Considerations
Would not achieve immediate results takes time and is not guaranteed to work.
Community may have concerns with introduced species.
Potential damage to the native plant community of the lake, which could result in the
establishment of aggressive other plant species as pioneers.
Concerns from fishermen about grass carp
Initial investment very expensive
The introduction of grass carp has generally been discouraged by State agencies,
especially in systems like Steel Lake.
Suitability for Steel Lake
Grass carp are not suitable for aquatic plant control in Steel Lake. The infestation of
milfoil has not reached a level where a bio- control such as grass carp would be necessary.
Their preferred food species include the dominant submersed native aquatic species in
Steel Lake, which might be grazed before the milfoil. They could remove all the
beneficial plants that support a healthy fish population. Without cover and the
invertebrates associated with beneficial native aquatic vegetation, the system would be
degraded and some species (invertebrates, fish, etc.) may be extirpated.
The lake also has an outlet stream that eventually flows into Puget Sound, making it
much more difficult to obtain the permits necessary to stock grass carp.
Watermilfoil Weevil
45
STEEL LAKE IAVMP APRIL 3, 2003
f';NAL DRAFT
The following information and citations on the watermilfoil weevil are taken from the
Washington State Department of Ecology's website on Aquatic Plant Management.
The milfoil weevil, Euhrychiopsis lecontei, has been associated with declines of Eurasian
watermilfoil (Myriophyllum spicatum) in the United States (e.g. Illinois, Minnesota,
Vermont, and Wisconsin). Researchers in Vermont found that the milfoil weevil can
negatively impact Eurasian watermilfoil by suppressing the plants growth and reducing its
buoyancy (Creed and Sheldon 1995). In 1989, state biologists reported that Eurasian
watermilfoil in Brownington Pond, Vermont had declined from approximately 10
hectares (in 1986) to less than 0.5 hectares. Researchers from Middlebury College,
Vermont hypothesized that the milfoil weevil, which was present in Brownington Pond,
played a role in reducing Eurasian watermilfoil (Creed and Sheldon 1995). During 1990
through 1992, researchers monitored the populations of Eurasian watermilfoil and the
milfoil weevil in Brownington Pond. They found that by 1991 Eurasian watermilfoil
cover had increased to approximately 2.5 hectares (approximately 55 -65 g/m and then
decreased to about 1 hectare <15 g /m in 1992. Weevil abundance began increasing in
1990 and peaked in June of 1992, where 3 4 weevils (adults and larvae) per stem were
detected (Creed and Sheldon 1995). These results supported the hypothesis that the
milfoil weevil played a role in reducing Eurasian watermilfoil in Brownington Pond.
Another documented example where a crash of Eurasian watermilfoil has been attributed
to the milfoil weevil is in Cenaiko Lake, Minnesota. Researchers from the University of
Minnesota reported a decline in the density of Eurasian watermilfoil from 123 g/m in
July of 1996 to 14 g /m in September of 1996. Eurasian watermilfoil remained below 5
g /m in 1997, then increased to 44 g /m in June and July of 1998 and declined again to 12
g/m in September of 1998 (Newman and Biesboer, in press). In contrast, researchers
found that weevil abundance in Cenaiko Lake was 1.6 weevils (adults and larvae) per
stem in July of 1996. Weevil abundance, however, decreased with declining densities of
Eurasian watermilfoil in 1996 and by September 1997 weevils were undetectable. In
September of 1998 weevil abundance had increased to >2 weevils per stem (Newman and
Biesboer, in press). Based on observations made by researchers in Vermont, Ohio and
Wisconsin it seems that having 2 weevils (or more) per stem is adequate to control
Eurasian watermilfoil. However, as indicated by the study conducted in Cenaiko Lake,
Minnesota, an abundance of 1.5 weevils per stem may be sufficient in some cases
(Newman and Biesboer, in press).
In Washington State, the milfoil weevil is present primarily in eastern Washington and
occurs on both Eurasian and northern watermilfoil (M. sibiricum), the latter plant being
native to the state (Tamayo et. Al. 1999). During the summer of 1999, researchers from
the University of Washington determined the abundance of the milfoil weevil in 11 lakes
in Washington. They found, that weevil abundance ranged from undetectable levels to 0.3
weevils (adults and larvae) per stem. Fan Lake, Pend Oreille County had the greatest
density per stem of 0.6 weevils (adults, larvae and eggs per stem). The weevils were
present on northern watermilfoil. These abundance results are well below the
recommendations made by other researchers in Minnesota, Ohio, Vermont, and
Wisconsin of having at least 1.5 2.0 weevils per stem in order to control Eurasian
watermilfoil.
46
STEEL LAKE IAVMP APRIL 3, 2003
ri t“ 1.
To date, there have not been any documented declines of Eurasian watermilfoil in
Washington State that can be attributed to the milfoil weevil, although Creed speculated
that declines of Eurasian watermilfoil in Lake Osoyoos and the Okanogan River may
have been caused by the milfoil weevil. In Minnesota, Cenaiko Lake is the only lake in
that state that has had a Eurasian watermilfoil crash due to the weevil; other weevil lakes
are yet to show declines in Eurasian watermilfoil.
Researchers in Minnesota have suggested that sunfish predation may be limiting weevil
densities in some lakes (Sutter and Newman 1997). The latter may be true for
Washington State, as sunfish populations are present in many lakes in the state, including
those with weevils. In addition, other environmental factors that may be keeping weevil
populations in check in Washington, but have yet to be studied, include over wintering
survival and habitat quality and quantity (Jester et. Al. 1997; Tamayo et. Al., in press).
Although the milfoil weevil shows potential as a biological control for Eurasian
watermilfoil more work is needed to determine which factors limit weevil densities and
what lakes are suitable candidates for weevil treatments in order to implement a cost and
control effective program.
Advantages
Milfoil weevils offer a biological alternative to aquatic plant control.
They may be cheaper than other control strategies.
Biocontrols enable weed control in hard -to- access areas and can become self-
supporting in some systems.
If they are capable of reaching a critical mass, biocontrols can decimate a weed
population.
Disadvantages
There are many uncertainties as to the effectiveness of this biocontrol in western
Washington waters.
There have not been any documented declines of Eurasian watermilfoil in
Washington State that can be attributed to the milfoil weevil.
Bio- controls often don't eradicate the target plant species, and there would be
population fluctuations as the milfoil and weevil follow predator -prey cycles.
Permit Requirements
The milfoil weevil is native to Washington and is present in a number of lakes and rivers.
It is found associated with both native northern milfoil and Eurasian watermilfoil. A
company is selling milfoil weevils commercially. However, to import these out -of -state
weevils into Washington requires a permit from the Washington Department of
Agriculture. As of October 1, 2002 no permits have been issued for Washington.
47
STEEL LAKE IAVMP APRIL 3, 2003
Suitability for Steel Lake
Since the milfoil weevil is a new bio- control agent, it has not been released yet
intentionally in western Washington to control Eurasian watermilfoil. It is uncertain how
effective the weevil will be and whether populations per stem can be maintained at levels
high enough to eradicate Eurasian watermilfoil. Also, as with the grass carp, the
infestation of milfoil in Steel Lake is not heavy enough to warrant bio- control
introduction when other methods are still available.
Rotovation
Rotovators use underwater rototiller -like blades to uproot Eurasian watermilfoil plants.
The rotating
to nine inches deep into the lake or river bottom to
blades churn seven o
p
dislodge plant root crowns that are generally buoyant. The plants and roots may then be
removed from the water using a weed rake attachment to the rototiller head or by
harvester or manual collection.
Harvesting
Mechanical harvesters are large machines which both cut and collect aquatic plants. Cut
plants are removed from the water by a conveyor belt system and stored on the harvester
until disposal. A barge may be stationed near the harvesting site for temporary plant
storage or the harvester carries the cut weeds to shore. The shore station equipment is
usually a shore conveyor that mates to the harvester and lifts the cut plants into a dump
truck. Harvested weeds are disposed of in landfills, used as compost, or in reclaiming
spent gravel pits or similar sites.
Mechanical Cutting
Mechanical weed cutters cut aquatic plants several feet below the water's surface. Unlike
harvesting, cut plants are not collected while the machinery operates.
Suitability for Steel Lake
None of these options are suitable for the level of infestation at Steel Lake. They are not
eradication tools, but rather are used to manage and control heavy, widespread
infestations of aquatic weeds. These processes create plant fragments, and therefore
should not be used in systems where milfoil is not already widespread.
In infestation levels recently experienced by Steel Lake, these methods would probably
serve to spread and expand the infestation. According to Ecology, "There is little or no
reduction in plant density with mechanical harvesting." Since the aim of this project is to
eliminate milfoil from the system, these are not compatible control strategies. Harvesting
and cutting do not remove root systems. Rotovation would cause damage to the lake
48
STEEL LAKE IAVMP APRIL 3, 2003
L
sediments and associated animals in a system that does not already receive dredging for
navigability.
Drawdown
Lowering the water level of a lake or reservoir can have a dramatic impact on some
aquatic weed problems. Water level drawdown can be used where there is a water control
structure that allows the managers of lakes or reservoirs to drop the water level in the
waterbody for extended periods of time. Water level drawdown often occurs regularly in
reservoirs for power generation, flood control, or irrigation; a side benefit being the
control of some aquatic plant species. However, regular drawdowns can also make it
difficult to establish native aquatic plants for fish, wildlife, and waterfowl habitat in some
reservoirs.
Suitability for Steel Lake
Drawdown is not a viable control strategy for Steel Lake. The outlet from Steel Lake
flows through a wetland to a natural stream system, and does not have a control structure
installed. Not onl y would drawdown be difficult to achieve, it would also cause
significant damage to the ecosystem. The amount of drawdown required to impact milfoil
would dry out the littoral zone of the lake. This would damage native plants and animals
in both the lake and the adjacent wetland and have many negative consequences for
residents living around the lake. Without a surface inflow to the system, returning the
water level to a previous state would be both cost and time prohibitive.
INTEGRATED TREATMENT PLAN
The following outlines control measures to be implemented to contain listed noxious
weed species, and other identified weed species, in Steel Lake and along the shoreline.
These control measures will prevent and/or halt the spread of their invasions and reverse
potential lake degradation. In addition, the eradication of noxious weed species will
provide the opportunity for the reintroduction of native aquatic plants.
The target species are Eurasian watermilfoil (Myriophyllum spicatum), fragrant water lily
(Nymphaea odorata), and yellow flag iris (Iris pseudacorus). In addition, native aquatic
weeds (i.e. thin leafed pondweed and submerged macro algae) will be controlled to levels
that do not impact public safety or the beneficial uses of the lake; and will be preserved
for fish and wildlife habitat.
49
STEEL LAKE IAVMP APRIL 3, 2003
Eurasian watermilfoil (Myriophyllum spicatum)
The aquatic formulation of 2,4 -D Aquakleen®) was used in Steel Lake the summer of
2002 to control an early infestation of milfoil. Approximately 5 acres were treated
around the lake with this herbicide. A follow -up visual survey in late summer of 2002
indicated that the Aquakleen® formulation was extremely effective and shown to be
highly effective for spot treatment of milfoil in Steel Lake.
The time released nature of this granular formulation is less susceptible to drift. Liquid
formulations can drift off target as a result of wind and /or boat activity. Therefore, liquid
formulations have a slightly higher risk of injuring off target organisms. In addition,
granular applications are visible the applicator can direct the product directly onto the
target plants. The granules adhere to the leaves, increasing the effectiveness
(Vandermeulen, personal communication). The preferred formulation for the eradication
of pioneering colonies of Eurasian watermilfoil is 2,4 -D (Aquakleen® or Navigate®).
As described earlier, milfoil can easily be transported from lake to lake on boat trailers or
fishing gear, and once introduced it can spread rapidly, infesting an entire lake within two
years of introduction to the system. It is widely distributed in Washington and difficult to
control. Because of Steel Lake's historical infestations of milfoil, and the danger the
introduction of this aquatic weed poses to the lake's ecology, an aggressive but
environmentally sound integrated treatment
plan has been developed.
0
Y g p p
In Year One (2003), a systematic diver survey will be conducted at the beginning of the
growing season (April -May) to identify milfoil colony locations. Selective diver hand-
pulling will take place then. Manual methods don't require expensive permits, and can be
performed on aquatic noxious weeds with Hydraulic Project Approval obtained by
reading and following the pamphlet Aquatic Plants and Fish (publication #APF -1 -98)
available from the Washington Department of Fish Wildlife.
Spot herbicide treatment with 2,4 -D (Aquakleen® or Navigate®) will begin in late May
to early June 2003. Approximately 3 -acres of milfoil will be estimated to have survived
the 2002 treatment, and require selective spot herbicide treatments.
A second diver survey will be performed later in the 2003 growing season to detect stray
or surviving milfoil plants; and to assess the effectiveness of the earlier manual and/or
herbicide control methods used. During this time, diver hand pulling will be performed
again, if required, to remove milfoil remaining after the herbicide application has had
time to take effect.
Each successive year will begin with diver surveys of the lake performed at the beginning
of the growing season. Following these initial diver surveys, the level of milfoil
infestation, if any, will be established. Using the survey information, the Steel Lake
Aquatic Plant Advisory Committee will decide upon the preferred control strategy to
contain milfoil populations at as low a density as is environmentally and economically
feasible. The need for a second annual diver survey will also be determined by the Steel
Lake Aquatic Plant Advisory Committee.
50
STEEL LAKE IAVMP APRIL 3, 2003
..ti FT
If significant milfoil re- infestations occur over time (greater than 3 acres), it is possible
that the aquatic weed has built -up herbicide resistance. In this case, Triclopyr (Garlon
3A) may be used if fully approved for aquatic use by U.S. EPA and by the State of
Washington (late 2004).
Milfoil is not known to reproduce from seed in this region, so there is no seed bank to
exhaust. Because the aquatic weed is introduced by boat traffic, the severity of re-
infestations cannot be fully predicted or controlled. Potential reintroduction will remain a
spot treatment application will be planned.
challenge. Due to this, an annual herbicide s pp p
g P
II I
Since Steel Lake does not currently have prolific plant growth, milfoil should be located
easily during the diver survey. Manual control methods should therefore prove to be very
effective. The goal of the treatment plan will be to limit annual herbicide treatment, if
possible, and control the majority of milfoil re- infestations by diver hand pulling. But
because of the continual threat of re- infestations, annual herbicide treatment of at least 3-
acres of milfoil will be conservatively budgeted for each year.
Additionally, there should be no need to re- vegetate the areas of milfoil after treatment.
Most of the native submersed species are monocots (Potamogeton sp.) that should be
relatively unaffected by either the 2,4 -D (or Triclopyr) application. Removing the noxious
invaders will halt the degradation of the system and allow beneficial native vegetation to
thrive.
Community public education efforts will also continue, including lake resident training in
milfoil identification and survey methods. In addition, improved signage will be located
in a position approaching the public boat launch to warn boaters before their watercraft
enter the water.
The NPDES permit coverage requires notification and posting of the waterbody, and
these specific protocols will be followed. The NPDES permit also requires monitoring of
the herbicide levels in the lake after treatment. Independent samples will be collected at
the time of the application and again five days post treatment. One sample is taken from
within the treatment area, and one from outside. These four samples (per application) will
be sent to an independent laboratory for the analysis. Surveys after the initial application
are essential to determining the success of the effort, and will be used to determine what
measures need to be implemented to complete the milfoil control.
Problems may arise if the same firm that conducted the herbicide application also surveys
for the success of the effort. To counter this potential conflict, City of Federal Way and
or lake volunteers will conduct these post- treatment surveys. Volunteers from the Steel
Lake community will be directly involved with overseeing the implementation of control
work to keep the contractors accountable.
Fragrant water lily (Nymphaea odorata)
51
STEEL LAKE IAVMP APRIL 3, 2003
`l
g
Control and containment efforts for fragrant water lily will be conducted on an annual, as-
needed basis. In 2002, approximately 8 acres of fragrant water lily were reported to be
colonizing the lake, with the majority at the west end of the lake. (Vandermuelen, 2003,
personal communication). In 2002, approximately three (3) acres of fragrant water lily
were treated with Glyphosate, (primarily at the west end). Glyphosate was selected
because of it's effectiveness, low cost, and low environmental impact. This aquatic
herbicide is a systemic herbicide absorbed by foliage and passed throughout the plant.
Since it kills the tubers, it results in long -term control of the plant community. It also
exhibits low toxicity to bottom dwelling organisms, fish, birds and other mammals, and
dissipates quickly. Therefore it is considered to have a low environmental impact.
In Year One (2003), a systematic diver survey will be conducted at the beginning of the
growing season (April -May) to identify and locate fragrant water lily colonies. The Steel
Lake Aquatic Plant Advisory Committee will review the findings of the diver survey, and
identify the necessary fragrant water lily control and containment methods (aquatic
herbicide and/or manual methods) to be implemented.
Herbicide treatment (Glysophate) if required, will begin in late May to early June. The
herbicide will be applied when floating leaves have formed on the water lily (late spring,
early summer). The applications may be followed by cutting and removing operations if
target plant areas are not killed by the herbicide.
Each year, the Steel Lake Aquatic Plant Advisory Committee will review the findings of
the annual diver survey, and identify the most effective and ecologically safe control and
containment methods required This integrated approach should be sufficient to ensure the
control and containment of fragrant water lily to levels that do not impact public safety or
the beneficial uses of the lake. In addition, a year -by -year, systematic eradication of this
noxious species will allow for the eventual re- introduction of desirable native aquatic
plants. This integrated approach, combined with the Fish Habitat Mitigation Plan
described in this IAVMP, will improve fish and wildlife habitat, and the overall
ecological health of Steel Lake.
A commercially available non mechanical aquatic weed cutter will be purchased with
Lake Management District funds for targeted manual water lily removal when the total
acreage is less than one acre: It would also be available to all property owners who wish
to control populations near their docks and waterfronts. The primary advantage of hand-
cutting is the low cost. The primary drawback is the high amount of labor required to
provide adequate control.
There are no depth limitations for hand cutting, therefore the control zone may include
any portion of the lake containing water lily beds. However, since it requires manual
labor, it is best suited for small patches of lilies that may be hindering lake access.
Hand- cutting should be performed by the end of the summer before the plants set seed.
Because the plant roots (tubers) are not removed using these tools, the duration of the
control is comparatively low. The frequency of the application will be dependant upon
52
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
water depth. Monthly cuts will maintain deep areas, but more frequent cuts may be
necessary for areas less than 3 feet deep. Although cut fragments of waterlily will not re-
root and grow as some submerged plants do, these fragments should be removed to
prevent aesthetic impacts from floating debris and onshore decay of plant materials. Cut
fragments float and are best removed with a modified fish seine that encircles small
working areas, or is positioned down -wind of the working area. The net should have at
least a 1 -inch mesh so that it will not trap small fish.
Another concern associated with the lily beds is the tendency for large "islands" to
separate from the main beds and move out into the lake. These floating islands are a
safety hazard; they can be unseen obstacles to boaters and attract children who can
sometimes stand on the islands, but who could easily be hurt or drown if they broke
through the mat of vegetation. Lake residents have tried various methods of removing
these islands, but they are too large and awkward to handle. A technique that was
successful at Lake Kathleen (King County) used a water pump and hose to wash sediment
off the vegetation. Sections of washed vegetation were then removed by hand and placed
on the boat for later disposal or composting. This technique is recommended for
removing lily islands from Steel Lake.
The Steel Lake Aquatic Plant Advisory Committee will identify problematic water lily
islands, and recruit volunteers from the community to remove these larger sediment mats
on an as- needed basis. A Hydraulic Project Approval from Washington Fish Wildlife is
required for this work. Smaller mats may be towed to shore and remove the sediment
with hand tools.
Other Submerged Plants
Immediately following the whole -lake Sonar® treatment in 1994, the submerged plant
population (other than milfoil) in Steel Lake maintained at a moderate density. As a
result, the small populations have not been causing a significant hindrance to recreational
activity. Therefore, the intent of the control plan is to identify the dominant submerged
plant community during the annual diver survey, and devise methods that can be used to
maintain their density to levels that do not impact the beneficial uses of the lake. In
addition, this program will not promote the growth of milfoil or other non native
submerged plants. Herbicide application is not anticipated.
A moderate level of control will allow the submerged plant community to thrive, and
allow a diverse fish and wildlife habitat. Methods considered will be focused on controls
that do not adversely affect the existing populations of other native plants. For example,
native submerged plants such as Nitella and Najas jlexilis do not grow tall enough or are
not dense enough to hinder recreation in Steel Lake. These are important plants to protect
since they provide valuable wildlife habitat and their presence eliminates plant habitat
that might otherwise by available for invasion by one of the more nuisance plant types.
53
STEEL LAKE IAVMP APRIL 3, 2003
FINAL
Each year, the Steel Lake Aquatic Plant Advisory Committee will review the findings of
the annual diver survey, and determine the need for the implementation of manual
methods to control targeted submerged plants. Manual methods don't require expensive
permits, and can be performed on aquatic noxious weeds with Hydraulic Project
Approval obtained by reading and following the pamphlet Aquatic Plants and Fish
(publication #APF -1 -98) available from the Washington Department of Fish Wildlife.
Examples of possible manual methods to be employed for control of submerged plants:
Depending upon plant densities and whether exotics are detected, additional diver
time during the annual survey will be planned for hand- pulling native plants in beds
that have been identified as potential problems. In deeper water, hand- pulling is best
accomplished by divers with SCUBA equipment and mesh bags for the collection of
plant fragments.
In water less than three feet deep, omeowners may perform this activity, as no
p Y p Y
specialized equipment is required, although a spade, trowel, or long knife may be
needed if the sediment is packed or heavy. Some sites may not be suitable for hand
pulling such as areas where deep flocculent sediments may cause a person hand
pulling to sink deeply into the sediment. Hand- pulling of aquatic plants is similar to
pulling weeds out of a garden. It involves removing entire plants (leaves, stems, and
roots) from the area of concern. They are placed in a mesh bag, and disposed of in an
area away from the shoreline, or composted.
Cutting differs from hand pulling in that plants are cut and the roots are not removed.
Cutting is performed by standing on a dock or on shore and throwing a commercially
available non mechanical aquatic weed cutting tool out into the water. Because of the
lower pondweed biomass, hand- cutting for these plants is less labor intensive than
that for water lily control. The equipment would be available to all property owners
who wish to control small populations near their docks identified for control by the
Aquatic Plant Advisory Committee.
In some cases, raking may be identified as a preferred method in removing submerged
plants. Attaching a rope to a rake allows removal of a greater area of weeds. Raking
literally tears plants from the sediment, breaking some plants off and removing some
roots as well. Specially designed aquatic plant rakes will be purchased for use by lake
residents to control small populations near their docks identified for control by the
Aquatic Plant Advisory Committee.
Yellow flag iris (Iris pseudacorus)
Control and containment efforts on yellow flag iris will be conducted on an annual, as-
needed basis. Each year, the Steel Lake Aquatic Plant Advisory Committee will review
54
STEEL LAKE IAVMP APRIL 3, 2003
L T
the findings of the annual plant survey, and approve the methods to be used (aquatic
herbicide and/or manual methods) for control and containment of yellow flag iris.
Because yellow flag iris appears at the shoreline, individual homeowners will be
responsible for the control of yellow flag iris colonies on their property.
Fish Habitat Mitigation Plan
The text below is adapted from "Aquatic Plants and Fish" published by the Department of
Fish and Wildlife Publication APF -1 -98
Aquatic noxious weeds can adversely affect ecological functions by crowding out native
vegetation and creating single species stands. While it is recognized that native aquatic
plants can become a nuisance to swimmers and boaters due to excessive growth, it is
important to recognize the value of native plant species for fish and wildlife. These native
plants provide habitat for fish and wildlife, help stabilize shorelines, produce oxygen, trap
beneficial nutrients, and keep sediment in place. For example, pondweed is a critical food
source for waterfowl and marsh birds. Pondweed also provides cover from predators for
warmwater fish such as perch and bass. Aquatic beneficial plants are defined as native
plants (such as pondweeds, bladderwort, or coontail) or non native plants not included on
the King County noxious weed list.
Warmwater gamefish often utilize vegetation in the shallow waters of lakes for spawning,
early rearing, and feeding. Largemouth and smallmouth bass generally prefer ponds and
reservoirs with abundant aquatic vegetation. Bluegill, sunfish and crappie also inhabit
vegetated quiet or slow- moving waters for protection from predators. Too much
vegetation
are unable to access prey species,
can result in overpopulation if redators
predators p Y P
while too little vegetation can also adversely affect the predator -prey balance and result in
a decline in the fishery.
r
insects, snails and crustaceans, which in
Aquatic lants provide important living space for i s
P Po p g p
turn become food for fish and waterfowl. Vegetated areas support many times more of
these tiny creatures than to do non vegetated areas. The plants make important nurseries
for young fish, frogs, salamanders, and other amphibians. Several species of reptiles,
including turtles, garter snakes and water snakes use these areas for cover and forage.
Removal of all non native plant species within Steel Lake may have a short-term negative
impact on warmwater fish populations due to a loss of habitat cover. With removal of the
non native vegetation, areas will likely re -seed with native plant species over the long-
term. The recommended extent of native vegetative cover for fish habitat needs is 40% of
55
STEEL LAKE IAVMP APRIL 3, 2003
r.,
the lake acreage (WDFW, personal communication). Previous surveys of the lake show
an average of 23 acres (50% lake coverage) of submerged native aquatic vegetation.
Based upon results of the annual plant survey, the acreage of the native vegetation will be
calculated. If there is less than 19 acres (40% coverage of the lake) of native aquatic
vegetation cover, the Steel Lake Aquatic Plant Advisory Committee should determine
whether mitigation measures are necessary to support wildlife species.
If mitigation efforts are deemed necessary, native aquatic vegetation will be planted
and/or wooden fish structures placed in the lake to supplement natural recovery efforts.
Native vegetation may include floating leaved rooted plants such as Brasenia schreberi
(water- shield); submerged plants such as Ceratophyllum demersum (coontail),
Utricularia vulgaris (common bladderwort), and Potamogeton spp. (pondweeds); and
submerged macroalgae such as Chara spp. (muskgrass) and Nitella sp. Fish structures
may be composed of wood snags, root wads, or Engineered Large WoodTM secured to the
bottom of the lake or some other stable environment.
COMMUNITY EDUCATION AND INVOLVEMENT PROGRAM
The community education and involvement program for Steel Lake consists of four parts:
(1) an Aquatic Plant Advisory Committee to oversee implementation of the plan, (2) a
non native aquatic plant identification and prevention plan, and (3) informational and
workshop activities to alert homeowners to stormwater pollution prevention and best
management practices (lawn, garden, home care activities) that protects the lake's water
quality.
Steel Lake Aquatic Plant Management Advisory Committee
Proper implementation of the described plan relies upon formation of a Steel Lake
Aquatic Plant Management Advisory Committee. The Aquatic Plant Advisory Committee
is to be composed of representatives from the lakefront residential community, the City of
Federal Way Surface Water Utility and the City of Federal Way Parks Art Recreation and
Cultural Services Department. The duties and responsibilities of the Advisory Committee
may be transferred to the Steel Lake Management District Steering Committee when
created.
The Advisory Committee will have the following responsibilities:
Review annual plant survey information and determine the need for a second annual
survey.
Develop an annual aquatic plant management workplan based upon the information
revealed in the annual plant surveys. The workplan will prioritize aquatic weed
problem areas and identify preferred control methods for each species.
Assist the City of Federal Way with oversight of control work to keep contractors
accountable.
56
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
Participate in preparation of an annual evaluation report that summarizes plant control
activities, lake user's perspectives on the plant community, and recommendations for
the next year's control strategy.
Assist with presentation of aquatic plant management efforts to lake residents at an
annual Steel Lake community meeting.
Ensure that all lake residents, whether legal water rights users or not, receive proper
notification pursuant to the requirements of the NPDES Noxious Weed Permit.
Determine and participate in other annual community involvement and education
strategies as needed.
Non- native Aquatic Plant Identification and Prevention
Eradication and control efforts will only be successful if future infestations are prevented,
or detected and eliminated soon after detection. Since the re- introduction of non native
aquatic plants to Steel Lake is almost certain, a prevention and detection plan is essential.
A more informed community of residents and lake -users will be more likely to identify
and report noxious aquatic weeds and other potential problems.
There are four main elements to the prevention plan.
1. Annual distribution of educational materials. The Advisory Committee will
compile published materials and generate literature specifically related to Steel
Lake for distribution to all lakefront residents each year.
2. Annual plant identification workshops. At the annual Steel Lake community
meeting, part of the meeting time will review native and non native aquatic plant
identification. Aquatic plant experts could be invited from the Department of
Ecology, King County Noxious Weed Control Program, or other experts.
3. Improved signs. Improved noxious weed identification signs will be installed
before and at the boat launch, in addition to the existing sign at the water's edge.
The improved signs will identify the species of concern and illustrate how boat
owners should clean their boats before entering and when leaving the lake. A trash
receptacle will be provided next to the signs for proper disposal of the weeds.
4. Boater outreach. Volunteers from the Advisory Committee as well as other lake
residents will conduct outreach efforts with boaters during opening day. Boaters
will be given educational materials about non native plants and instructed on how
to revent re- infestation of the lake. Boaters may be approached at the boat launch
P Y pP
and/or on the water by other boaters.
Non -Point Pollution Prevention
Significant sources of nutrients can increase the occurrence of aquatic nuisance species
such as cyanobacteria. Reducing the nutrient impacts to the lake will help reduce the
outbreak of algae blooms. To protect the lake from water quality degradation, residents
within the Steel Lake basin will be provide educational as well as instructional workshops
on how to reduce the amount of nutrients running off of their yards, into the storm drain
system, and into Steel Lake. One example of an effective program is King County's
57
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
Natural Lawn Campaign including the Natural Yard Care program. The City of Federal
Way currently participates in the Natural Lawn Campaign through the Solid Waste
Division. The Natural Yard Care program is planned for implementation in the Steel Lake
basin in Spring 2003.
Other issues of concern for the non -point pollution prevention program include 1)
maintenance of sewer system and septic fields, 2) reducing residential car washing
activities, and 3) disposal of residential hazardous materials such as paints and car fluids.
These topics may also be included in the community education and involvement program
as determined by the Advisory Committee.
PLAN EVALUATION
The results of the aquatic plant control program must be evaluated against the goals set
for the lake. In short, the program will have been a success if: 1) milfoil re- infestations
are prevented; 2) the herbicide (glyphosate) treatment and manual controls implemented
in designated fragrant water lily areas are successful to an extent that is acceptable by the
majority of the lake users, and, 3) manual controls for water lily and native submerged
plants are successful, reducing the populations to levels where they do not significantly
impact the beneficial uses of the lake; or do not negatively impact fish and wildlife
habitat. It should be noted that this is a working plan, it is not necessary that all the goals
be achieved by some given date, but instead that the lake plant community is continually
being evaluated against these goals and each years control plan is developed accordingly.
The annual aquatic plant survey will provide the primary support for the evaluation plan.
The results will provide evidence to evaluate: 1) if milfoil continues to be eradicated; 2)
the extent of coverage of fragrant water lily beds; 3) whether beneficial submerged plants
are continuing to inhabit much of the submerged plant habitat; 4) whether there are
changes in the density of other native submerged plants, and 5) the effectiveness of fish
mitigation efforts.
Each year's plant survey results will be evaluated against the stated plant management
goals to set the following year's plant control agenda. This evaluation will be supported
by City of Federal Way Surface Water Management staff input.
PLAN ELEMENTS, COSTS, AND FUNDING
Table 9 provides a summary of each element identified in this plan and the associated
costs. The total ten -year cost for the plan is estimated at $166,440, including a 5% rate of
inflation each year, for an average of $16,644 per year. The majority of the cost occurs
during the first year when equipment purchases all occur. Depending upon the revenue
generated to support plan implementation, the Advisory Committee will determine which
58
STEEL LAKE IAVMP APRIL 3, 2003
0 DRAFT FINAL
elements of the plan to implement on an annual basis. For example, the annual funds
available may not cover all activities identified in this plan in year one (2003). Therefore,
the Advisory Committee will need to prioritize activities based upon funds available.
To implement this plan and provide a long -term funding source for continued plant
control activities, public education, and evaluation, a stable long -term funding source is
needed. Funding through the formation of a special taxing district, a Lake Management
District (LMD), is to be completed by 2004.
ana applied Department of Ecology Aquatic Weeds Management Fund can be pp lied to for
additional funds to augment funding provided by the LMD. However, Ecology grants
require 25 contribution from the applicant (City of Federal Way). Other possible
funding sources include King County's Water Works and the Natural Resources
Stewardship Network. In addition, the King County Noxious Weed Program has limited
funds available to contribute to weed control projects.
Table 9. Estimated Cost for Implementation of the Steel Lake IAVMP
Plan Element 2004 2005 2006 2007 2008 2009- Total
13 10 year
Aquatic Mapping /Survey 4,000 4,200 4,410 4,630 4,860 28,170 50,270
and Report
Milfoil eradication
Spot herbicide treatment 1,725 1,810 1,900 1,995 2,095 12,150 21,675
(2,4 -D) (Note 1)
NPDES permit fee 100 100 100 100 100 500 1,000
NPDES permit notification 400 400 400 400 400 2,000 4,000
(Note 2)
NPDES monitoring costs 1,000 1,050 1,100 1,155 1,210 7,000 12,515
Fragrant water lily control
Spot herbicide treatment 1,500 1,575 1,655 1,740 1,825 10,575 18,870
(glyphosate) (Note 3)
NPDES permit fee (Note 4)
NPDES permit notification
(Note 4)
Contract cutting (Note 5) 1,200 1,260 1,360 1,385 1,455 8,420 15,040
Submerged plant control
Diver hand pulling (Note 6) 1,200 1,260 1,320 1,385 1,455 8,420 15,040
Equipment purchases
Weed cutter 130
Rakes 200
Fish habitat structures 2,000 1,000 1,000 4,000
Pump, generator hose 200
Public education
Printing and Mailing 1,500 1,500 1,500 1,500 1,500 7,500 15,000
Natural Yard Care 3,500 4,000 7,500
Program
Boater outreach 1,000 1,000
Totals 19,655 13,255 14,745 14,290 14,900 88,735 166,440
59
STEEL LAKE IAVMP APRIL 3, 2003
FINAL DRAFT
Total 10 year Cost 166,440
Average Annual Cost 16,644
Costs are based on an annual increase of five percent (5
Note 1. Based on treating 3 acres of milfoil, one time per year
Note 2. Beginning in 2003, a legal notice must be published in a local newspaper annually.
Note 3. An estimate based upon treating 2 acres fragrant water lily annually
Note 4. The same NPDES Noxious Weed Permit for may be used both for milfoil and fragrant water lily work done in
the same year.
Note 5. Assumes contract cutting at $150 /hour for 2 days
Note 6. Assumes divers working at $150 /hour for 2 days
Appendix A
King County Water Quality Graphs
60
STEEL LAKE IAVMP APRIL 3, 2003
0
I
l
V
i J
E
J
i
E
III
Steel Lake
LL
I r--- 47.4 acres d
i
Public Boat
i r Launch i F
f
N
a
1 L
I 1 n
N
v
m
0
c
y
'ji h c
n
1 is
Figure 1. Steel Lake Watershed Land Use
Storm Drain Outfall I I Common Ownership
Sub basin Boundary LANDUSE Park
N Wetlands Commercial Quasi Public
I I II Steel Lake Park Boundary Industrial Religious Services
—0- Lake Outfall Channel I I Multi Family Single Family
0 250 500 1,000 Feet 1 I Steel Lake Shoreline Office I Vacant
cAstlkbasin.mxd
L a-
as
C
u
co
_Nc
(r)
E
co
75
I
s
I a)
a)
C:)
0
0.1
1 I
I
0 I ca
0.)
..ct
I 0 I I
I co
CI 0
C I
a.
co
2
I o
g
I 0
0
1 i
0
i
I
0,
1
E
1!
I
t 0 I .2■C
I V's
I
CD i
CO
I r
i -c)
u..
I
4-0 1,,,,
44: 1
0
0
1
I -1-0
1 .c
CL I—
I
I a i c
0
LO
E.
E
(Xi 0
0
■..I I'
Q.
I 40
a) a)
To
r-
LO cn
as
to
.1■•• 1 1
IL an 1
1
t iI i i
as
co
N
{u,
,i,ir Y
IC I I i. N
co
co
z
i 1 r--- N
1
1 I O
O N,
CO
I. q(tU�( O
III
CO i t) O
O
N
1 j
1-1) i 1 e i .1: n
m
Q ,I
i
t (4 I U
5T1 7
l
1 O
:I T c9( II Ct CO j it
m
NI J
1
_III �1
CZ
I T
l
U N
w
0
o
1 co
Q N N v
�C I E'
I s:„...... Cr
IS O o
0
L
1 U U c
0
Q� i� 1111 I CO
TO
r u o�11 II' 1 (LS -D 2 1
v.
I I N N :..S.:
a
J I III I I V III I I Iu L III I t JI L II il t W J N
ll o E.�u)w l I I IIINIII► Niui���III,,,,
III► g I
1ii1
1111111 ____11 111 111 1 11 lIr>;1'
6_
as t
C
t
03
la t
-E- 1
Ii
<:.3 z
0 i
--g
co
_c t
'15
al I
r
w
11 1 1 1
i
le
7
o
I 1—
:\s ,s.N„,,,
(N1
0
(cCO
4.) 1
11
0 0 I
0
0 1
:.:.,..i.:
IP'
nI
I 4
i la i
/0)
c
0
i
e
r---i 7
E
I
I I
i
1`
i
1)
(13
al
0
(4
I
al
1
cri
0,
1
5
C3 1/7
W
W
C[
W
If
(0
I i
0)
E 70
75
I
n
cz
8:
1 li
A
co 0 2
0 0 E i
2 i
ti
0
(T3
13 (ZS 0 c 1
1g 1
"47-.
W E E
112 i
f
I'
cr Z 0) `r i 11 1
:1
1 I
m a) a)
0) 0) c
1
qv-
CD w a) •(.7.)
a.)
2
I 1111 il
c E E E3_
ti
__I W
D ti
a) w
(13 I
a 2 I I 11 1 1 11111
II III 1111 I I
0 IL w
v 1
w
1 1
1
ci)
u) I--
'1111111 111 1 111 I Ilk
1 I 1111111 1111 11 11 11
111 11
c3)
g
co
III 0111111111111111'
w 4 7;
D
D CM
111
cy) D
ri
�i -ul, _�IItt1 i a
1
A
Y
III Z i
i
3
CO
L
W
N
...,,:,.-11--
CD N j
C
CD
I l i hi
o
J
c
II
im 1 111,.
00
N i Hu IcN i il 2
N u
I.L. 1
O
`n
ai LO
II :T i AIL-517-4;
I III N T
Q N i
U
N I N (6 m
-Y -1-' 7 fi I
(Y III c o Q. O
1 Q O L O L o
N cc II C13 CO E
G (III j 2
co s_ r N 03 N N n
II -T a)a)c
O
1 1
1111
cB N N
n _c
IrnM CO
II
,11111_..
1 110
d as
C
7
NNN
_Ne
1 z 17)
I
15
co
th
lb
f
a
c\I I
I
t a) i N.,
1 1
E i
a co
1 al l'I
a)
I 0
0 cis'
ca
i- 1 i 0_
14 GS
(1) i I I I
1 L.- t
I d 1 r„....------......,
0 1 I
1
1
1 rD 1111( i i I 1 1
I i i 401"An/
c
I I 1
1 1111 1 III t
71-. i E
i 12°
(..0
03
1 1 i
1 I
'cf
(Y) 1 I 1 I
7 e
w 0)
I i
o
N--
t
al
tv 2
1 1 x
i
1
0- 12
i 1
t°
l'i
111 a)
u_
a ill 1515:
a) -0
li
tli 0 0:
....le E
as as o_ o
I I Ca. 1 0-
0 0 E
-0 as a3
a) w 1111.
Ea E 1 E: 3
1
ai p p S
al (1) a) a) .1
---r cm o) c t
1 CO C CD L- co '1
I
0
a cLE,
D _c cn
'1 W
N I 0 EL (1) (1) W (l)
1 it N., 1111 11 7: '0
1 I I
I A E
I
cll rc3 7 15 -7 :i lni =;:ty :._.7!
L 1. Fl 1 L L i
l Fr? U0 I
..,etia<dwillogill
0 L ...i..--,
0
cz
i
1,•■ X,t4IP L 1 I
0 a 1kS3'; .&i.7..: CJ j1 C1-1 B E •I'a
0 r
Fr W. h. 1 r 41.- N I i a
Li 0 1 u.) o
II 0 5- AI r„..,.,..„..., C-3
1 0 c:::_i A Azw'is" %"4-1-v• CS M
1- -CI
1
0 1 liveltr... i'llSISN 4,1
ti' s .4. 4-4:• VI
1 A a)
a y.,
Ca af m g
IA M 4-.
0 E) t 140151:. (1) C
1 E-
C 0_
[bEj 711411'
,4_.,/_ 111
i, Ji1,11/_cr. c
73 e:71.1114:11113 .11WA,"
o
E'c_. )1 .011t:
I lririr
111111'',„ as CT
cr +a
C
R ii. '11 1
N CD
2 E
.1..1
3 (<15) I I
ci 1- -LAlinim littris it f p,
Iii CS IIIMEh lit", r I c=i Eq,4 4 5 1
.3) -0
a
iri Itnit.
Iiii4
liennits,. A., v• 0 r CD a)
114 0
Are ANAty z
0
L 1 iligardaMil&MBP:174#4.. Q r CI 0 CA
LL
.c.- 1 infint....,_)-WV,. k ll (tDi I 15
FL? 'wiz, Ae Alp
0 Mitilir. -;"1
C•4
0 1 •;:'..■.,51151111Wi!:Ylii t i l l I. El ___.i‘ 1
I 1:11 'Ili:i.V:IY.;:.*;:.':'...7:?.).?'3..11 re i l l I,: L.:i Z 1 f
01, D
..zz.:: 11.1 11 0 1
I T.,
rn
I 0 lililt :41:10011yr, i i i..
Itotlk.i.i.t," til I.,
,YLI•I J y i i .1 r
V. 01 I i l i y i lf z
S
ri l'ilin
tli 1 t ..c.
1
1 y‘ C? 3
n
iit.1 in X 31 'i
1
4 4 4
4 4 4 4:• E.c 1 c
4 Mil Fp Q3 G3 I li ii l' 1
1 4
..._.•--r tE M IN i
0 0
,7.7,-.---.1r.
7 •fl I
--Al_ k 1 s N w 4 1 L I Li Li 6 I li d' I u)
c
i 0
1 e.f: 4.. t g....:\ L`-,j *0 0 i
dir...-:•.-,
al
Ni
r n i
Illtia\'' .„,P L n 1 1
1
0
i ffiko tt. Nik II cj 6 B i r
+.1
1
0 a
0
lit C3 ri NAs /ff.r:....t.747e.fit 0 L___.3 1
1 a c=i Am- AM %.(mento.ltiti, CD cn 0
ler Mil N,- .144*.
03
D o was 4,01261;411._ NI., 0 ..C2
1 grac;.-'. s.;...%,%,---:------- I--
0 loa /ism f!...f -5: Ni..
4-
0 r, f
P Er- tiolit
a)
0 a r t til 6
1 E3 !V
S it'.
z ....i. I
4—I
U)
CZ
Ili= rlii:-,
+j w s 0-
7° ,71 ittill :3 Hari o
:ffir,.,
co
311111' 111fficr
NI
ti i t .fl lifft
C
D WW1
1 1 •I. lint
CD
C=3 r g
o as 4
I D k ketr. Qn i
i
f .4, V
r E■1
liffeji C'4 I=1 S...
0 F.
li E3 1 Olin liffil t I 1 C 0 11 E g 0
0
4 4..0
n li II 4 ED 0
vim lial
,,d .11111.:
0 CD
cy) c
c-,3 4 tilt 1 iif -L 9
B
..saimi,stg lio D
u Cil
liffriti
/4.t. R o p G 3 cf
'R
I III 1/f Amg 5 A ...f::Y. ATA1. 111W7WF•011J.Wft j 1 C] D
0 0
CJ)
0 IMEREW '''ttriii. HI,
"---ri li
4.,
0 ettill‘ki .3 .102F G3
0
f_..9 111,111,i'101:..1:4.1•A':•1:751.141(0041:!::11i1 %I I• rr ie
Z -0
i El ci11,1"1":".1:-1+;f:"-I•.1-1:::i71.11.■:.;;;Y:li g:
i P T...I u. tillilitillIIIIIIIIII„ i t i lV 114 IIIII D
r fl
1 0 Ns1 1 .1.1.1.1.1 1 0-1 ..!--.1 ri
y000 ,0.1.10,1, 1 i t A t i 1. I
co-
5
1 'Id t L "it' 1 1 1 1 1 4 1 0 1: Te
11 011, •r r
C S i
B
Iiiiio,14.. 8
.4,1,,,..' ZY
,c1
I 3 i."1 1
1
<2
4 4 4 4 4 1 1 11 :1
I e f i ....t
...1..-
Fp
I' Et E ,m.
ide uisegNlis\iums\u /siasn/ o II. 1 i r I; S t (t
rj i I ri I ii! y't I i. f I; F 1 h`, j �i N '�{f t w' Pr t�y"S t, ,,i, t,,,o• �ji f• ji t S t ''R S t'w. r t t iil I <I '1 r L ►R1 I 1 i T r ti t m li kl l t r :r f i t l R r e 1 J. l r* 2i if -,1 1 1 I;G 1 I lli !1 I 'I 7 105114 (0
n le 2
41,, t t, i i' Id 4- '11..•1' :i l
t .A. ''I' i, F I L t.SI. '4.
i1, G ti t i d i�- if F Y 1 LL �i'
fi t �i 1: 1
S t 1 i i r 444.1 i* IY 4 h R
s ;41 i F 1'
i. I �r i I y .1 t I 1 ,,r: r r! I I t F` 1 i e f 1
1 4 1 f 1 11 1 w4r. !71 y
1
r�,r r�{ a i fit W ((t ti .4 iv w y l t i I F Vi c {i ,.1 1
#I 4Plf i aj i j s- '.`111 l 1 !t I y t 'ilii 1 1 1.,0
I '1 ,!1 I Il #�C�c Ft� 1 i rf c .i a: ;i1,4•1 I il I 4 M p'j. ,�j 7 ;.1 a 1 11. il,. ii 'Fff T,I .'v t i f 9`r r S. t r t i� 1 r. 1
r te' t, 1 :�L gg 1+ a.
K SaC' t+ q r
}illy 7 k -i 1 r N i fi t... t u gyp I ,1. I
I!P i x, f Y P
j
ti 11 i I r :1 i }r r ',�'!o G a 1 :i M -6-,
'1 Ni: h.. I t.• u t iQ 4kl, >1 't f ili r u, j f i_
L ...4 .c _I ti'- t i y A•'Si r
'f" �5�1 1 i 51 :jt i u O
40
L; s. r I ti "1 i1 11 1 4_1
j4j�
,[.1 I 1 I i r'M. 'Nr7 1 F a +1
M a 1
i t 1 r der r h. ii S• I S r 1 j I O
c cll •lit ht e i' I:'
i 4. r `t t c .''''1.-:,i,:,..., S j aM. IkSS -.ft t1 i• h
IFS t 1: k t 1 11 1 O
r t t�i y^ 4,.. a n 1 t lgl F t. CV
i I:11'011%11 1 tr it ,1111 1
I rf i t r.i 411 r 1 01.4'.
i1 p liitft` t
F e t r /y ,i,r 1.;
1 j• 7' i •1 t a 4t oke' t 5' 1 4 1 i i 4 1 S c1. M' W. i t
1 t I lle. s ti. i c S
x .1'4' t i i1 i l y c`:. f 1j I i-
Id O 1. tt a i 1 i' t 1 1 1 rl A�A�}i�;'i. 1 i t tr
o t i,: l ill: 1 t+1 1'�tl
._+i- '•,ti ,,,,t,'4•7•47-p• ,Ik1 -inat a t S s v j t y
0 •!1", C 1"-`11„-'4:‘, J y 2 t S i t #t 1
t I 7 1• L 1!1 R q� li 1
----:•,.1,'.: 4.. tx t 'F.�, 7 .(•�ty., r 1 i c 1
.;1( N L' '•t- t 7 4 4. 4
0 ff ee e r I a 1 V f 'St k;r
u
l'' 1 i �y 1
Cy) 4 i f M q l 4 z e t P it .F.r T 171
:J.' I, AI 1 k_� I fiit r i I, 6 t et .`rlf t ,M� ken' "r I 1 1 1jn 'i
a r'
y 1 t ip!! f 7 ✓.a i 1 1 .6 ,1 1'1:67
011. l! •„-:,:,,,.,.....;,,,,,,,i,
i it +it i 1;;Vrti 1 s i A
4. vot i t t' 4 I 1 t
a A .4-. 1' ,.!4,
I 1 i s i1 W .I 4«' •.T' w
i Y i' j
Fn r 1 K 1 2 1 'i. I t
1.
i y L L y4� w r r �1•1L" 1 u e r y may f� t G
7 7k ?S ►'tf w ater i V s a l S.
rw: 'aM" y7jfp''171 -y .�7*Z 11. �441A.I 7:2'.'. f: .../...,r,.
1 i
1 ',:el.,' 4 4•S,+• •�a t %"S��i. tiid 0: i' 1 W' 9 _4:441
r on
Afmr •e• 4'111 ..c........ p j
IC Y 7'1J Al t ..r
Qoemooe Si k of se ueJJem ou sa>,ew /eM }eIapa. 10 40 ay 1_ t(kuo uoyeluasaidai 1eol4dei6 e se papuaful s! s!y1
ide ulse4>{Ils\wums \we41!4e1 /siasn/
Qz N
O
q7 y.: a t f y 1 ss I riy .14 1' 1W1i r �.3r t F ?d i q 4 i 3 y t r 1,• 1 n v y. 11 1 I asF ti
s I j f 1 7E[ f 11 1 3, 1 p i Y;• t I t1 w r.• tt', l t w_.t Jr �t k` E
N 1. .t
4 l p i 1 ti y ,4; tA-4 P.",! 4 y t o 3+ .f 3 rw' c\1 zt• th 11ii Y•, I II' E i 1 if q x 4 t
'4 l a 3 r ;t 4 Si^7i j t #r y t 7 i �f7L (n r 1q I t 'f� i I� ji tJ
a R t r r. 4�
..F N G ;f1 E 1 {'131 milki0�f 1 i! ii i J
4 Ss1 1. 1l g i (3 J., t �r; 1 .y rt 1 tru 041 i
"r•-r, f r' rt t, r, s �l, t 3. .o s g
111 t f t Y. +B 1
�i 1l M E' Eg�y. '4',47,,„141 t >w a.
.ii,:. O h lt∎ 1 T i i gyp t, W. N�f 1 V j M�
3 1 N p� .1 loot,: t 1 k S 1 f r 1 c /t� 4 s 1' 1
t
}df 4 t 1A gar
1' 1 f: 1 1 RF i f f t1 �X t 1N
Li i J L' 1 f C 1., 1 i W(v J'
yr •T a t °'>X R i f k i K� 3 1 t 1 e• G r d i
ry w •a I 1 I e 1 •E I I ii ,ii ..i. ••d�8:,: 11 ,ti11
If 1 'a 7:0;.- 1 L. p I 1 1 11 ii I 1 LL
I~ L .t_ "Z 4, •?'.t 1 I I l 1 1 1 .s f 3 s c y. C 1 t iY O CD
X 1 5 i e 1 I I 1 F. V
E L, f O s e i 6 t N 1 4 5 :1 1 1 ,1 r• E i 7 N. S. 1
f Rd
I l ,1, i n s
U M 1 ti i 7 11 11 1 1111 1 11'11 1 1 7 1 I1 i7 1 is" u j II
..:{..,4 :44..,,, *i1 I 1 l i I 1, a i i't O G J u '1' I l' 1 I I I i, j O
t� J 1 1 7 i i t 11111111 11 1 l' 1 1�J' 111t,1 i( ;1 ii i t� 7 )I ht I I 1 I i! 1111 11111 I (111 (dt ul'.. t;EP1 ,1 N 1 t iw I, 1111 '(t Il 1 ,E 1 1 i iT ?iY r i t4! (Si a�. ltr I 1 I I I1 1� i le:-,q.,17 r "t t f 2 'Y..� 1 1 A t I 1111 l,,l !ii Ii, l(1 1 l I 1 it r l_ t i
Y.i 3. 1 i i UPI 11111{II� i 11111'
1 t Will 1 I II 111 ,A e f i
rc�'.1. t t :„,'.1.- i.11,
"34t` °a y a i 11 I 1 1 1 i ij'ii 1 1 I y 1 /3�t�� a .4 L 1 1 111 1 i 1,'1 h r� :i. 1 i I I S I� ,1 1 11 4 1 1'11 i 1 'f tr1 '-ii. jll e.,�( c "t, I
t y
al Y 9i Y. ii t 1 1 1 i t 1, i'i 111111 1 11111 11 }11 r- ;r 2K41 jE t1 1 1 f R' S -1�
er 1.�' I r I I 1 111 .i l �i• 1 f� 1 t ,1 11 I t 11 1 11 Sf'• v E 4 s J a- 11
j
1 `'-'-1 ,.1'r SE7! 1 1 I 11! i• 1 1 3 i i i t
im, 1 1 11 11;111,11 f 1 .r i t i t +1 Sl;i r
it i i I11 1 1 11 Ii 1 4 I i1 1 1 i 1 1 1111 *w •1 h f
t''.'''''
H t :fEg. .L Pi 1 1 1 1 1' 1 1 1 I i 1 11 1 r1f 1, '4. r i s r 1 1 y YS ti i.. i 1 i 3 1 1 1 110f 11 1'i� ,I .ti, ‘1-4.=•" w t i x o 0
4 era, if et V -11:9 i 1 I 1 1 1 tI�} 1 2 i 1 +E r' ll,t
3 j
J •r/M1 k r ft• V V�l tlVl= 2.� 1 111 1 +1 'j 1 11 '"t"kT N N
VJ tt v° 4 l 1 1
1 1 r fi u t l 1 4 r 4:,_.,1 '1V...'111.• r m m
te r h al ot t i 1 1 1 k� a. r f l .l I' l .r 1 11 1
r 1 1 ,>E�y �11 ;I. 7 i 1 1 11 l� 1' I h 'T ti� 1 1 i i J ',,i
,d c° m
1 t. y E 4A N 1 I 1 i i I 1 t i. 7' .za t d fsll '6. V o m
LjJ n 1 f 11 i
r 11 "1 1{' I i IiiA t !l j 1 1 1 I l 1 ,t i'�� i t .a. 1 d
-i I 1 1: f•i r �11 1�1- i 'i F S k 1 as
CO, A;; 4 d' 111 1 �1 -,11 J n
fi r 1 h i( i( I r,4 S #t lir
F,1-'7 E .o 1 11 1 11 1 111111 1 I 1 k U,= 7!" 11 I j1 i y 11 lit 'I 1YS',*••. I
7 J
N r f if "'3 ..iii; F .1......-. r 1: 'i11:. a
E
m' h 1 i`- t 1 l f, e
r �r E
V 14 4 CD 7'... r„ES ,s 3..! f A4 1 r 4 4' ,1 S j i a w
t 4%,
y u, f x..1-,-;•••,. (SG� 4 1. 3 i'• �dr i 1 19 r d i
..6.. t ,n A M •i i. 11 Y V 1411 I S O 1
r j am f r �M �f ,Vii} S Y f
loeinooe s1 01 se /elueiiem ou sa>Ieul /eM ieiapa j Jo Alp a41 uo uogeluasaidaJ 1e014dei6 a se papualul s1 slyl
1
A P ure 14. 2001 Steel Lake Secchi DepI(King County)
Level 1 Level 2
E0.0
i 2.0
a b 4.0 6 4 *44. N t III
t
a 6.0
2 y8�.0
LA 1 1
o
to a o o c b o o a c o
a O u. 2 <t 2 to O
O
Figure 15. 2001 Steel Lake Precipitation (King County)
L. F P recipitation Lake Level-
"E" 100 T -100
E so+ E
0 60 40.4* 50 a
ro
40 a
a
20 25
O. i a 0 PA 9. I I II 'illy 0
O O z p 7 u- 2 4 2-- alb d U?
N CO N d6 O IL N
N N
Figure 16. 2001 Steel Lake Temperature (King County)
r Level 1 Level 2
30.0
G
20.0 6 r
a st
F- DA O
OA
0 0 o a o b o b b o
c m o a b b m a U
O
b. 2 a 2 a O a
Fire 17. 2001 Steel Lake Phytoplank•Concentrations
5
Total phytoplankton
4
3_
2
n o� to (13 Q Q
(O O A N N (D 8) C•1
N
BG chrys tEdino pother
Phytoplankton Chart:
BG= Bluegreens; chrys= Chrysophytes; dino Dinoflagellates
Figure 18. 2001 Steel Lake Chlorophyll Concentrations
15
Chlorophyll a
12
9_
6_
A T C C 7 7 3 0) Q Q' V. U
(6 (0 7 7 7 3 N N
7 to 7 Q Q c 0
to p
(.1 r r N N
Figure 19. 2001 Steel Lake Total Phosphorous/Total Nitrogen
__Total Phospohrus ....—Total Nitrogen
100. 1000
Average N:P 27.4
80 800
60 600
TP TN
400
20 200
0 0
3 3 5 0) o) 0- 0 2"i 2'i
m co 7 7 m O O
6 6 CO t� r N N 6 6 N
N r a N N
hL m=eT
m o c ni
5cu =cu
CO D (0 CO og ,e L
El E
t C j C
1- .6 s3 (1)
5LL
in IF i g e 6 E
3AV H1LZ
M WE
E co
ld H19Z l vow w
o
C
El
g o
0 T3 7.-. a
O dH19Z .,,,,z.v.3.:.3._
ma �4
a O
H1bZ
co
v
1 M INIIIEWMI
2 ENS
o 2
'PAM =WV aba
MIMEO ma
L
E i
N
C
M
v n
IV El El
o M cp
Elm m
W
ink I Lain r i
I
JI_ a.
N
2
J q' Wl fi In lL
Aru�seg►s w.ww WIQiI M
or
M
O
a
N
CO c0 CO 0 c0 c0 ca c0 c0 CO c 0 c0 CO 0 0 0 CO CO O)
N CO 0 CO 0 CO CO CO 0 CO c0 a) Ti (6 f0 0 E E m 0 f0 w
a aaaaaaaaa0O00 as omm 00&)0
N z z Z z Z z z z z z a z Z z z (0 z Z z a
m 0 CO c0 CO CO m co l0 0 c 0 0 CO 0 m of c0 c
masmmosmmmmcaa) rs0 co ed mw vs Ili ci
a
0 aaaaaaa 0 0 0 0 0 as a) 0 0 aar) 0=
CV o 0 0 0 0 O 0 0 0 0 E o o 0 0 a 0 z z 0 0 0 E
ZZZZZZZZZZaZZ zz 2 zz Z
C c c cc
ccc a)a)�a
mm
0 c C me c m caco was
0 cum o a) C 0 a) a) a1 a) co C co C C 0 0 l0 0 as
Ea2 E E. o my 00000
o¢a.< Loa a. 00 000 z
c0 0 C c C C C C C 0 0 0 m N S m N
CO C a) N c o c a) a) o Q) a) a) c co a) 0)
E .n22_D Emm E cots 0000
0 ¢a¢ aoa¢a¢¢¢ o0 00,:; zzZZz
co c
c C c
o v` cut a) a a)a 00co)a ca
E2 L' m -r. N
W
vi.... a N WW O C O W N N c0 m 0 O O c,,
0) EE a En m-vm a E a aaa c) m
_a 0a a¢ ¢o¢a¢ 0¢ mmm
V y C 'E —E c C c C a) a) a) alas
o) H C N N C O N C y a) a) .g8 222
c0
E2 a EE o C L82 o o c(!)-N
a oa oo a o
a 'od
n c y a c N 0 c a) a) a) c 0 22 N N O r
Ed EE WE E) 00.a
oa op. ao¢a¢ Da °mm
O
co a) a) a
n c a c c a
i ai c L' cL' 2 cn c0 0) (0
E d .o 2 E 2 Ea. E E E n.nn coop °0
Tv ao Op_ WOW
c
22_2
c C C C cco C m c c c m 2 E
n n Ew E EE WE amm s) E a00 0),-
0 a a a0 a 0 a0 2z
a)
0
v
a
0 0m zTL a°')ao)25w_ °(5 m
8) E dm vv n 0 0 2
y oz m m cum 0 o a mz z
U aa�3 O3 U t
a
-O L
c a
es o
Y L
c0 E u
ai 0 E m
c i 5 E .6 R g 9i
a) a.
i i E a) .0 0 r N E ut m m c Q 7 y y 03 0 E i O co 0 w p F i
c o o �m E m a3-o c'-' i E c rod co 11 g e
C C 3 0 a' QP N a
O O 000 d d m C N It ''c C ql p d o a 0 O M a
LL a) a, 0 e 0) a) O N S ,9 0.n. 0•= O .0 0 5
I1; V
as
Attachment "B"
DRAFT
Petition to the Federal Way City Council to Create a
Lake Management District for Steel Lake
We, the undersigned Steel Lake property owners, request that the Federal Way City Council
approve the creation of a Lake Management District (LMD) for Steel Lake pursuant to RCW
36.61. The LMD funds will finance efforts to protect and enhance Steel Lake in terms of water
quality, recreational and aesthetic value.
1. Purpose of the Lake Management District:
Form a Lake Management District that creates a funding source for all future aquatic
plant management activities, and continue to seek grant opportunities.
Perform annual diver surveys to monitor changes in the aquatic plant community.
Control and contain both milfoil populations and fragrant water lily populations at as
low a density as is environmentally and economically feasible, and at levels that will
not impact public safety or the beneficial uses of the lake.
Reduce all other identified species of noxious weeds as listed in WAC 16 -750 to
levels that do not impact public safety or the beneficial uses of the lake.
Use appropriate aquatic plant control and treatment methods as needed for all other
problematic aquatic weeds, using the best available science to identify and understand
their effects on human, aquatic and terrestrial ecosystems prior to implementation.
Provide for adequate native vegetation for fish and, if necessary, mitigate for any
negative impacts to fish habitat due to non native plant removal activities.
Continue public education to prevent the introduction of noxious weeds, nuisance
plants and non native animal species to the lake; and to aid in the early detection of
aquatic weed re- infestations.
Continue to involve the Steel Lake Community in the aquatic plant management
process.
Conduct public education to reduce the amounts of non -point source pollutants
entering the lake, which can result in an increase in aquatic algae.
2. Boundary
The proposed boundary of the LMD would include all the property with lakefront on
Steel Lake. See attached map of proposed properties within the district.
3. Duration
The proposed duration of the LMD is 10 years.
4. Charges to property:
Annual rates and charges will be used to raise funds to support LMD activities.
The following is the formula of rates and charges proposed for establishment of the
assessment role for the LMD:
Property assessed on dollar per unit
Type of Units Rate/Unit Total Percentage
Undeveloped parcel 7 $30 $210 1%
Developed parcel (1
single- family 89 $85 $7,565 57%
dwelling)
Parcel with multi- 1 $275 $275 2%
family dwelling
City Park 1 $2,048 $2,048 15%
Public Boat Launch 1 $3,500 $3,500 25%
Annual Total $13,598
The estimated maximum amount that is proposed for the LMD in 2004 is $13,598. An
automatic increase based on the Seattle Consumer Price Index (CPI) will be included in
each annual billing after 2004. At no time is the increase to be more than five (5) percent
per year. Total maximum LMD rate revenue for the ten year LMD based on an annual
five percent increase for inflation is $166,440. Issuance of revenue bonds is not proposed.
The attached Steel Lake Integrated Aquatic Vegetation Management Plan includes an
estimated itemization of the use of these funds for the ten -year period.
The LMD budget and rates will be approved through a public hearing and a public vote
after the city council adopts a resolution to form the LMD. Once approved by the public
and city council, the annual rates and charges may not be altered without another public
vote and city council approval with the exception of the CPI increase described above.
5. Steel Lake Management District Steering Committee
The volunteer Steel Lake Management District Steering Committee is proposed to
represent the interests of LMD property owners in the various neighborhoods around the
lake. City staff will work with the Steering Committee to develop the annual work plan.
The annual LMD work plan and budget will be forwarded by the Steering Committee for
implementation by the City's surface water utility. The Steering Committee will track
and review activities and expenditures by the City as well as outside contractors. City
staff will provide Steering Committee support including quarterly financial reports.
Attachment
Steel Lake Integrated Aquatic Vegetation Management Plan
2
i
1 o S!W!
0
1, col._ 1-1 I-
N S �1b LZ 1 I
t1) 0) co
i i 1
N H- V) M u) c3 cn co
m S id 9Z S /1b 9Z
Q 1
o w� Sid9Z` aDY c,, sml CI.
a j u l co f a
a)
S id VZ au JC
CO ft...11 S AV trZ
S AV CZ
1 i S 1D
t7Z
Ir
AV ZZ
a S AV V
Onsi
Q
ot N 1 AV QZ
flJ t CD
Y co CO
ti
1— S /1b 8 I.
1 g II CO g c ps co
,,,.1-,
gi y o
lit k 0)
CO
1at 4M H
III, t
o s AV 9 I-
Proposed Steel Lake Management District a b
Basin: LPSB Sub basin Code: CPR
sad*: Owned State Owned NO
0 230 400 6 Key: Vacant Multi- Family r) Single Family f A
Petition to the Federal Way City Council to create a Lake Manage District for Steel Lake
2003
Signature of property owner Full address Parcel number (if known)
)7#, i m =zu 7
..t 74, /cI A,/.e s r0 f2 S41e. Z s
TN A 1
3. &DSt 1 3-g Au S. MoNrc Q r:c c
4 L. 4 0 V i e o 3' 3i G hf ire> s /L/A/f-4
5 1/._, .;,4 t" t 0 A A I 0
6. I I), 0' 1 1 Za9 s off' p 41e D' '41
7 <6 ffrgif W (/2'
,ef2.07e,, pte,k,,H,
8 02 illi7 s. 3oy
q o i'56 so, 3d y 'Sf-
i l 10 3 ta -i ��Y 5
ti lr ,'l am
11. k S k%' Acycl Dz AUeS
12.4, v,, r- 2 r -.*)q Au-ritu2
13 lk, i 1 Q.C b l..Q`X'1 q
14. 4 h 2.1 .S. 9Gci rJ
i 4 141
I v 1 --='"---3-- ,,,w-i 7 :vout-i -111Yie,G Ae,(501
I lk
3
04/14/2003 MON 07:27 FAX 4252378281 ENABLING TECHNOLGY a004
Signature of property owner Full address Parcel number (if known)
4 z 4 .15 saur,Fr Sa YTasr
1.7 �e to tVAr WA 9a'd 092 /a5- 9ds9 a3
A �t133 so, 3oj c
21 J��F(, d d i G. e-u.l y r av 5'4 67.2 /0 7/O( 0
2.411 S 300'
3 M F c\ e
4 JAI 0
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
3
0
'd
0 4k
a L) a
Ve
U
Q>
4
1.., a J 1
S m
v a J
ca
A M
c U
d P4
E
44 o 6 r
wo U o
111
1 L
M
V o 43 0
o w
.7. s1
C
CO
V 1
al
I. a
g
c
cn
w
44
o r.,_,.
k
\s
a
b
0
0
1
0,
3
g `1
1
i
3
es --W V, 64
i
C cd
a a
t' 1S f1 C'^ 1
I TI) a) „o v
it
0
v
7. A
'0 M
d c I,
be C U o
Cis
,n V
wa
4? 0 0 fY
4-. 0
CI o o 4
U
t cg
.1) A
::4, 1
U A
o
a 0 .i V7
P., t,-) P, 0 M
eu 'T3
o C Q j
0 1
0 4, �a
.1
cw4 N C (c
1
1
1
0
cd
4,
o
C.) O v
a a
To' U
Q� 0
i. j n
H U M A
A a in
0
0 j
U p4
E
o N M
b o
a
a w
0 �w
w
0 r
al V
N
w b
a -0 i
0 b
0
f.
3 mi.-
r
z 4