Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017

HICKS LAKE INTEGRATED AQUATIC VEGETATION MANAGEMENT PLAN – 2017

Prepared for City of Lacey

Prepared by Herrera Environmental Consultants, Inc.

Note: Some pages in this document have been purposely skipped or blank pages inserted so this document will copy correctly when duplexed.

HICKS LAKE INTEGRATED AQUATIC VEGETATION MANAGEMENT PLAN – 2017

Prepared for City of Lacey 420 College Street Southeast Lacey, Washington 98503

Prepared by Herrera Environmental Consultants, Inc. 2200 Sixth Avenue, Suite 1100 Seattle, Washington 98121 Telephone: 206-441-9080

Funded by Washington State Department of Ecology Aquatic Weeds Management Fund Grant Number WQAIP-2017-LacePW-00001

February 17, 2017

CONTENTS

Executive Summary ...... iii 1. Problem Statement ...... 1 2. Plant Management Goals ...... 3 3. Lake and Watershed Characteristics ...... 5 4. Beneficial Uses of Hicks Lake ...... 11 5. Aquatic Plant Community ...... 13 5.1. Plant Distribution ...... 13 5.2. Targeted Plant Descriptions ...... 17 6. Past Management Efforts ...... 19 7. Aquatic Plant Control Alternatives ...... 21 8. Aquatic Plant Control Scenarios ...... 25 8.1. Noxious Floating-Leaved Plant Management ...... 29 8.2. Native Nuisance Submersed Plant Management ...... 30 8.3. Maintain Lake Health ...... 31 8.4. Contingency Management ...... 31 9. Selected Action Strategy & Implementation ...... 33 9.1. Action Strategy ...... 33 9.1.1. Action Strategy A ...... 33 9.1.2. Action Strategy B ...... 35 9.1.3. Potential Water Quality Impacts of Action Strategies ...... 37 9.2. Implementation ...... 37 10. Public Involvement ...... 41 11. Monitoring and Evaluation Plan ...... 43 11.1. Aquatic Plant Surveys ...... 43 11.2. Water Quality Monitoring ...... 43 11.3. Annual Evaluation ...... 43 12. References...... 45

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APPENDICES

Appendix A Hicks Lake LMD Steering Committee and Public Meeting Notes Appendix B Aquatic Plant Control Alternatives Appendix C Invasive Aquatic Plant Identification Appendix D Public Awareness Signs

TABLES

Table 1. Physical Characteristics of Hicks Lake and Watershed...... 5 Table 2. Comprehensive Plant List, Hicks Lake Surveys 1995-2016.a ...... 14 Table 3. Summary of Permitted Aquatic Herbicide Use for Hicks Lake...... 19 Table 4. Aquatic Plant Control Options Considered for Hicks Lake...... 23 Table 5. Plant Coverage on Hicks Lake ...... 25 Table 6. Preliminary Annual Costs of Aquatic Plant Control Scenarios for Hicks Lake in Lacey, Washington...... 28 Table 7. Fragrant Waterlily Management Options on Hicks Lake...... 30 Table 8. Common Water-Nymph Management Options on Hicks Lake...... 30 Table 9. Annual IAVMP Costs for Hicks Lake Action Strategy A...... 35 Table 10. Annual IAVMP Costs for Hicks Lake Action Strategy B...... 36

FIGURES

Figure 1. Watershed and Surrounding Vicinity for Hicks Lake, Lacey, Washington...... 6 Figure 2. 1995 – 2015 Trophic Status Indices for Hicks Lake...... 7 Figure 3. May through October 2015 Profiles of Temperature (°C), Dissolved Oxygen, pH, and Conductivity for Hicks Lake...... 8 Figure 4. Hicks Lake Aquatic Vegetation Density Map, Lacey, Washington...... 16 Figure 5. Hicks Lake Aquatic Vegetation Control Map, Lacey, Washington...... 27

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EXECUTIVE SUMMARY

Hicks Lake lies within the City of Lacey in the Henderson Inlet watershed in Thurston County, Washington. The 160-acre lake experiences dense growth of nonnative and native aquatic plants that inhibit the recreational usability and aesthetics of the lake. In 2015, members of the Hicks Lake community worked with the City of Lacey to establish the Hicks Lake, Lake Management District (LMD). The LMD applied for a grant to create Hicks Lake’s first Integrated Aquatic Vegetation Management Plan (IAVMP).

Hicks Lake has a large population of nonnative fragrant waterlilies (Nymphaea odorata) that has been present on the lake for many years. Recently, native submersed aquatic plants, primarily common water-nymph (Najas guadalupensis), have colonized most of the nearshore area of Hicks Lake. The presence of these two plant species is a safety concern for people swimming in the nearshore area or those trying to access deeper waters. Boating access and fishing are also hindered in the nearshore area by these plants. Some fragrant waterlilies have been treated with herbicide in the past, but the common water-nymph has never been treated at Hicks Lake.

This IAVMP details strategies for continued management of fragrant waterlily with the herbicide glyphosate, as well as the control of the nuisance native common water-nymph with the herbicide diquat. This IAVMP is a planning document developed to ensure that the Hicks Lake LMD community have considered the best available information about the water body and the watershed prior to initiating control efforts. To tackle the difficult task of generating community awareness and action for an environmental issue, a core group of residents formed a steering committee, which includes ten lake residents and one staff person from the City of Lacey. Members of the Hicks Lake LMD Steering Committee worked in partnership with Herrera Environmental Consultants, Inc. (Herrera) to develop this IAVMP for Hicks Lake using a grant to the City of Lacy from the Washington State Department of Ecology Aquatic Weeds Management Fund.

The goal of this IAVMP is to establish a maintenance level of control to meet recreational goals with an integrated approach that minimizes the use of herbicides to reduce the potential impacts of chemical inputs to the lake.

The Hicks Lake LMD Steering Committee was presented with two strategies for vegetation management. This 2017 IAVMP details the selected action strategy for management of the following aquatic plants:

• Noxious Floating-Leaved Plants – Treat one-third of fragrant waterlily (excluding the conservation area) with glyphosate annually for the first 3 years (approximately 8 acres each year from 2017 through 2019). Each treatment will involve an initial treatment, followed up by a second treatment a few weeks later to treat any plants that may have been missed because the pads had not surfaced or the herbicide washed off the leaves.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 iii

After 3 years, all waterlilies targeted for control will have been treated. Follow up spot treatments to maintain recreational access to open water habitat will take place in Years 4 and 5 (2020 and 2021). In Years 2 through 5, waterlily root mats that have floated to the surface will be hauled by boat into the conservation area and anchored in place.

• Native Nuisance Submersed Plants – Treat 13.1 acres of medium to high density growth of common water-nymph once every other year with diquat. One treatment of this area will be made at the beginning of the growing season (late May or early June), followed by a second treatment approximately one month later to treat any regrowth from seed germination. In Year 1 (2017) it is assumed that all 13.1 acres of the medium to high density growth of common water-nymph will be treated. The cost estimate assumes that in following treatment years (Years 3 and 5 [2019 and 2021]) up to 6.5 acres will be treated. It is possible that other native submersed plants may become dominant in the lake following the first year of treatment. For example, perennial plants such as pondweeds with extensive rhizomes often become dominant following treatment of annual plants such as common water-nymph. Therefore, treatments in Years 3 and 5 may target medium to high density growth of other native submersed plants, but are still expected to be limited to an area of 6.5 acres.

The aquatic plant community will be surveyed and mapped every other year to evaluate general changes in the plant community and effectiveness of the treatments, and to detect the presence of new invasive species. The control strategy is taking an incremented approach to treating target species to preserve the water quality of the lake; therefore, the presence of targeted plants such as fragrant waterlily does not alone indicate success or failure of the IAVMP to achieve the desired results. Success will be largely determined by public perception of whether the desired beneficial uses of Hicks Lake are being maintained through the implementation of this IAVMP.

A water quality monitoring program will continue to be conducted every year to track long-term trends in water quality within the lake.

Public education and awareness programs and workshops for lake residents will be focused on exotic plant prevention, and will provide general pollution prevention and best management practices information to lake residents.

The LMD Steering Committee and interested lake residents will be involved in development of the yearly plant control strategy and will be responsible for soliciting volunteers for surveys and planning of plant control activities. This will ensure long-term involvement of lake residents in lake management decisions and activities.

An annual report will be prepared documenting past and planned aquatic plant treatment activities, aquatic plant survey and water quality monitoring results, and public education and awareness activities.

The following contingency management options may be conducted as the need arises.

February 2017 iv Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017

• Fragrant Waterlily Root Mats – If the floating waterlily root mats inhibit access to the lake and are too large or abundant to dispose in the conservation area, then remove floating waterlily root mats and associated lake sediments from the lake at the public boat launch and dispose of as compost material at a landfill.

• New Noxious Submersed Plant Control – If the lake becomes infested by another noxious submersed plant such as Eurasian watermilfoil (Myriophyllum spicatum) or Brazilian elodea (Egeria densa), then immediately use hand-pulling or an herbicide to eradicate the infestation.

• Noxious Emergent Plants – Treat emergent noxious weeds that are known to occur on the Hicks Lake shoreline, such as Japanese knotweed (Fallopia japonica), reed canarygrass (Phalaris arundinacea), and yellow flag iris (Iris pseudacorus) with glyphosate annually when observed during waterlily treatment to eradicate or keep populations low.

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1. PROBLEM STATEMENT

Hicks Lake is a 160-acre lake within the City of Lacey in Thurston County, Washington. The lake lies within the Woodland Creek Watershed, which is within the Henderson Inlet watershed. Many of the residents around the lake have enjoyed a long history of living on the lake and are dedicated to preserving the beauty and recreational value of the lake. The Hicks Lake, Lake Management District (LMD) was formed in 2015 with the goal of preserving the aesthetics and recreational opportunities of Hicks Lake through removal of problematic aquatic vegetation. The Hicks Lake LMD Steering Committee is spearheading the development of Hicks Lake’s first Integrated Aquatic Vegetation Management Plan (IAVMP) to address aquatic vegetation issues.

Recently, native submersed aquatic plants, primarily common water-nymph (Najas guadalupensis), have colonized most of the nearshore area of Hicks Lake. They interfere with activities in nearshore areas of the lake that are less than about 14 feet deep. The density and extent of these plants are a safety concern for people swimming in the nearshore area or those trying to access deeper waters. Boating access and fishing is also hindered in the nearshore area by these plants.

Hicks Lake also has a large population of nonnative fragrant waterlilies (Nymphaea odorata). The fragrant waterlilies, a Class C noxious weed, are most abundant on the south shore. These lilies have been treated with the herbicide glyphosate at some properties in this area. Decaying roots (rhizomes) from the treatments have resulted in floating lily mats, which can interfere with lake use and present a safety risk to boaters when they drift across the lake.

Since 1995, plant surveys on Hicks Lake have identified several other aquatic plant species that are listed as “noxious” because of their tendencies to overtake a lake. Small populations of swollen bladderwort (Utricularia inflata) have been found primarily on the steep (eastern) shore of the lake, and curly-leaf pondweed (Potamogeton crispus) was once found near the public boat launch. These plants were not found during the aquatic vegetation survey of the lake conducted in 2016 for this IAVMP. However, a plan for prevention and detection is needed to reduce the potential for new plant invasions that could become problematic.

Emergent plant species (plants that grow along the edges of lakes, rivers, and streams) are present at Hicks Lake and include several noxious weeds that are not required to be controlled. Yellow flag iris (Iris pseudacorus) is expanding and restricts lake access in some areas, but is not yet a serious issue. Purple loosestrife (Lythrum salicaria) or garden loosestrife (Lysimachia vulgaris) have been reported at a few locations, but their presence is unconfirmed. Cattails and other emergent plants are not considered to be a problem by lake residents.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 1

2. PLANT MANAGEMENT GOALS

Aquatic plants in Hicks Lake provide important natural habitat for fish, waterfowl, and small wildlife. Excessive aquatic plant growth, however, may impact the aquatic habitat. Recent increases in the cover and abundance of aquatic plants have impacted recreational opportunities and aesthetic beauty the lake offers to residents who live on and nearby the lake. To address concerns of the Hicks Lake community, the Hicks Lake LMD Steering Committee is acting to create an IAVMP for controlling excessive growth of noxious weeds and native, nuisance vegetation in Hicks Lake. The Steering Committee is composed of ten lake residents (Danny Kaiser, Ken Callaghan, Margaret Hollinger, Mike Mahoney, James Tilque, Glenn Edstrom, Jay Monti, JJ Baker, Rob Krell, and Roxine Mahoney) and one staff from the City of Lacey (Tom Palmateer).

The Hicks Lake LMD Steering committee met three times during the drafting of the IAVMP to discuss the goals of the plan, as well as to discuss possible methods for control of the problem species to meet the goals, and finally to select a preferred method(s) for achieving those goals. These meetings took place on July 26, October 19, and October 26, 2016, and on January 17, 2017. In the third and fourth meetings, all members of the Hicks Lake LMD were invited to attend and provide input for the IAVMP. Notes and presentations for each meeting are provided in Appendix A.

With the implementation of the IAVMP, the Hicks Lake LMD Steering Committee will direct aquatic vegetation management activities to ensure a high-level of lake health while balancing the recreational, wildlife, water quality, and aesthetic needs of Hicks Lake. To accomplish this, the LMD established the following aquatic plant management goals.

• Provide for safe swimming in private and public areas

• Provide safe lanes of access to open water for swimming and boating from shorefront properties

• Monitor for plants that can become a problem and have a ready strategy for their control

• Develop a long term invasive species prevention plan

• Maintain good water quality and prevent toxic algae blooms

Because the studies and plans necessary to determine the condition of the lake and identify potential solutions for improving conditions are to be conducted as components of this plan, the above goals are broadly defined. Work plans will be developed annually for implementation of specific activities and recommendations based on current conditions and past successes.

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3. LAKE AND WATERSHED CHARACTERISTICS

Hicks Lake is a relatively shallow lake within the City of Lacey in Thurston County, Washington. Hicks Lake lies within the Henderson Inlet watershed. The contributing basin to Hicks Lake encompasses approximately 1.8 square miles.

Hicks Lake is the first in a series of four lakes that eventually discharge to Henderson Inlet through Woodland Creek. The other lakes are Pattison Lake, Long Lake, and Lake Lois. There is an extensive network of wetlands between these lakes, including a large wetland complex adjacent to the south end of Hicks Lake (Figure 1).

The primary land use surrounding Hicks Lake is residential, although there is some undeveloped forest and commercial land within the watershed. Hicks Lake has two public access points located adjacent to each other on the west side of the lake: a Washington Department of Fish and Wildlife (WDFW) boat launch and Wanschers Community Park, managed by the City of Lacey (Figure 1).

Hicks Lake has a total surface area of 160 acres and estimated volume of 2,700 acre-feet. The maximum depth is 35 feet, with an average depth of 18 feet (Thurston County 2015). Physical characteristics for the lake are presented in Table 1.

Table 1. Physical Characteristics of Hicks Lake and Watershed. Basin Area 1.8 square miles Surface Area 160 acres Lake Volume 2,700 acre-feet Maximum Depth 35 feet Average Depth 18 feet Shoreline Length 2.4 miles

The Thurston County Environmental Health Division monitors water quality in Hicks Lake from May through October each year. There is a record of annual monitoring for Hicks Lake dating back to 1995, except for a data gap in 2009.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 5 Figure 1. Henderson Hicks Lake Vicinity Map, Lacey, Washington. Inlet Legend

Hicks Lake Basin Lake City Limits Stream Highway

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Hicks Lake water quality monitoring takes place on a monthly basis at one site located in the deepest part of the lake. Water temperature, dissolved oxygen, pH, and conductivity are measured at 1-meter intervals from the lake surface to near the bottom, and water transparency is measured using a Secchi disk. Two samples, one from near the lake’s surface and one from near the bottom, are analyzed monthly for total phosphorus and total nitrogen. Additional samples for chlorophyll a and algae are also collected (Thurston County 2015). Much of the following information is taken directly from 2015 Hicks Lake Water Quality Report (Thurston County 2015). In the most recent water quality report, the water quality of Hicks Lake was reported as generally good, with phosphorus levels within the state standard (Thurston County 2015).

Carlson trophic state indices (TSIs) are used to express the degree of productivity of a lake. Average summer total phosphorus, chlorophyll a, and Secchi disk readings are each used to calculate TSIs. TSI of 0 to 40 indicates an oligotrophic, or low productivity lake. TSI of 41 to 50 indicates a mesotrophic, or moderately productive lake. TSI of greater than 50 indicates a eutrophic, or highly productive lake characterized by poor water clarity and high algae growth.

Annual TSIs for Hicks Lake are presented in Figure 2. The 2015 TSIs for total phosphorus, chlorophyll a, and Secchi disk were 40, 52, and 45, respectively. The average overall TSI for 2015 was 46, representing mesotrophic or moderately productive conditions. The chlorophyll TSI reached into the eutrophic, or highly productive range. The Secchi disk TSI was within in the mesotrophic, moderately productive range. The total phosphorus TSI fell right at the upper edge of the oligotrophic, or low productive range. The 2015 TSIs are within the range of those seen throughout the period of record, but the total phosphorus TSI was particularly low, equaling the minimum value previously observed in 1996. There does not appear to be an upward or downward trend, but rather cyclical pattern is apparent in the results. Sampling conducted in 1981 by the US Geological Survey found Hicks Lake to be in a mesotrophic to eutrophic state.

Figure 2. 1995 – 2015 Trophic Status Indices for Hicks Lake.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 7

May through October temperature, dissolved oxygen, pH, and conductivity data measured from the lake surface to bottom in 1-meter increments are displayed in profile graphs (Figure 3). Thermal stratification is when there are two distinct layers of water in the lake, a warm surface layer (epilimnion) and a colder bottom layer (hypolimnion). Surface water warms as sunlight penetrates through the water, but deeper water, where sunlight cannot reach, stays cold. The warmer surface layer is less dense than the lower layer, and these layers are separated by a thermocline (or metalimnion) where water temperatures rapidly decrease with depth.

Figure 3. May through October 2015 Profiles of Temperature (°C), Dissolved Oxygen, pH, and Conductivity for Hicks Lake.

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The 2015 profile graphs show that the lake was stratified from May through October. In August, surface water reached 22 degrees Celsius (°C) while temperatures at the bottom were only 9.7 °C. The lower water in mid-summer, generally below 19 feet (6 meters), had very little oxygen. This anoxic (no oxygen) condition results in a slow release of phosphorus from sediments into the water near the bottom. The release of phosphorus from the sediments often stimulates algae growth in fall when the lower and upper water mix. In 2015, the lake did not mix completely until after the sampling season ended, so the effects of this mixing were not recorded. However, some deep-water nutrients mixed with surface waters as the thermocline deepened during the summer.

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4. BENEFICIAL USES OF HICKS LAKE

There is a public boat launch maintained by WDFW on the west side of the lake. The boat launch is adjacent to an undeveloped public park, Wanschers Community Park, which is maintained by the City of Lacey. These two sites allow for public access to the lake. The residents living along the shoreline maintain private access to the lake. Lake residents and visitors enjoy fishing, swimming, boating, and water skiing.

WDFW stocks Hicks Lake annually with rainbow trout and occasionally stocked with brown trout. In addition to stocked fish, the lake supports naturally reproducing populations of black crappie, bluegill, largemouth bass, yellow perch, rock bass, and brown bullhead catfish (WDFW 2016).

Hicks Lake provides habitats that are integral to the lake ecosystem, such as bird nesting sites and fish rearing and spawning areas. Beaver, swans, heron, river otter, muskrats, waterfowl, osprey, and eagles have all been spotted at Hicks Lake.

Conservation areas are essential to the preservation of wildlife habitat and natural vegetation. Although nuisance plants within Hicks Lake limit access and recreation for lake users, they also provide shelter and food for fish and wildlife, which are highly valued in the Hicks Lake community. Due to the benefits these plants provide to fish and wildlife, a minimum of 10 acres of waterlily and 50 percent of the native plants will be retained annually; this is reflected in this IAVMP. Several properties along 1,200 feet of shoreline in the southwest part of the lake are undeveloped and considered as a potential conservation area where aquatic plants will be preserved. Native plants growing in low densities will be preserved in other parts of the lake.

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5. AQUATIC PLANT COMMUNITY

5.1. PLANT DISTRIBUTION

Hicks Lake has a thriving community of native and nonnative aquatic and shoreline plants. These plants can be divided into three general categories:

• Native – Beneficial

• Native – Nuisance

• Nonnative – Noxious Weeds

The term “noxious weed” refers to those nonnative plants that are legally defined by Washington’s Noxious Weed Control Law (RCW 17.10) as highly destructive, competitive, or difficult to control once established. Noxious weeds have usually been introduced accidentally as a contaminant, or as ornamentals. Nonnative plants often do not have natural controls (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, and C) of noxious weeds based on their distribution in the state, each class having different control requirements. Class A weeds are required to be controlled. County Weed Boards are given some discretion as to setting control priorities for Class B and C weeds. The state also maintains a monitor list for certain plant species, which are weeds that are under consideration for noxious status.

The categorization of native plants is more subjective. Generally, native plants are considered beneficial because they often provide habitat and forage for animals, compete with nonnative plants, and perform other ecological functions. Native plants become a nuisance when their growth is excessive and out of balance to the point if impacting the beneficial uses of the lake.

The Washington State Department of Ecology (Ecology) has records of plant surveys on Hicks Lake dating back to 1995 (Ecology 2015). In that time, 37 emergent and aquatic plant species have been identified at Hicks Lake (Table 2). The most recent plant survey was conducted by Herrera Environmental Consultants, Inc. (Herrera) on August 29 and 30, 2016. The survey was conducted by two aquatic botanists using an inflatable boat and motor along transects spaced up to 120 feet apart. The lake was surveyed by following transects perpendicular to shore.

Vegetation density and water depth data were collected along each transect using a Lowrance® HDS-7 underwater sonar and global positioning system (GPS), and data processing was provided by BioBase®. Vegetation density was calculated and interpolated between transects based on the relative proportion of plant biovolume in the water column. If there was little or no vegetation in a given location within the water column, the biovolume was recorded as low density. If plants took up a large portion of the water column or came to the surface of the

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 13

Table 2. Comprehensive Plant List, Hicks Lake Surveys 1995-2016.a

Plant Type Common Name Scientific Name Status Abundance 2016

Common cattail b Typha latifolia Native Low Common spikerush Eleocharis palustris Native Not observed Japanese knotweed Fallopia japonica Noxious Weed- Class B Not observed Longroot smartweed Polygonum amphibium Native Not observed Marsh yellowcress Rorippa palustris Native Not observed Emergent Plants Narrow-leaf bur-reed b,c Sparganium angustifolium Native Medium Peppermint Mentha x piperita Native Not observed Purple marshlocks Comarum palustre Native Not observed Reed canarygrass b Phalaris arundinacea Noxious Weed- Class C Low Smart swampweed Polygonum hydropiperoides Native Not observed Yellow-flag iris b Iris pseudacorus Noxious Weed- Class C Low Floating-leaved pondweed Potamogeton natans Native Not observed Fragrant waterlily b,d Nymphaea odorata Noxious Weed- Class C High Grass-leaved pondweed b,c Potamogeton gramineus Native Low Floating-Leaved Large-leaf pondweed b,d Potamogeton amplifolius Native Low Rooted Plants Ribbon-leaf pondweed b Potamogeton epihydrus Native Low Spatterdock b Nuphar polysepala Native Medium Watershield b Brasenia schreberi Native Low Floating Mat Rooted Water purslane Ludwigia palustris Native Not observed Plants Free Floating Plants Lesser duckweed b Lemna minor Native Low Big floating bladderwort Utricularia inflata Noxious Weed- Monitor List Not observed Common bladderwort b,d Utricularia vulgaris Native Low Common water-nymph b,c,d Najas guadalupensis Native High Common waterweed b,c,d Elodea canadensis Native Low Coontail b Ceratophyllum demersum Native Low Curly-leaf pondweed Potamogeton crispus Noxious Weed- Class C Not observed Nuttall’s waterweed b Elodea nuttallii Native Low Submersed Plants Pond water-starwort Callitriche stagnalis Non-native Not observed Quillwort species b Isoetes sp. Native Low Small pondweed Potamogeton pusillis Native Not observed Spineless hornwort Ceratophyllum echinatum Native Not observed Tapegrass b Vallisneria americana Native Medium Western watermilfoil b,c,d Myriopyllum hippuroides Native Low Whorled watermilfoil b,c,d Myriophyllum verticillatum Native Low Muskwort species Chara sp. Native Low Plant-Like Algae Stonewort species Nitella sp. Native Low Aquatic Moss Common water moss Fontinalis antipyretica Native Not observed

a 2001-2015 plant surveys by Department of Ecology (Ecology 2015) b Plants observed in 2016 plant survey c Species with herbarium specimens prepared from lake samples d Species with photographs from lake samples

February 2017 14 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017

water, the biovolume was recorded as a high density. In addition to the sonar, an aquatic plant sampling rake was used to collect a total of 10 grab samples for identifying submersed plant species and estimating the percent abundance of each species in the samples. From these grab samples, it was determined that common water-nymph was the most dominant submersed plant, composing approximately 95 percent of the submersed plant volume. Visual observations from the water surface were also used to assess plant species abundance. A total of 20 aquatic and emergent plant species were identified within the survey area during the 2016 survey. Out of those species, three are classified as noxious weed species in Washington State, none of which are required for control in Thurston County (NWCB 2016, Thurston County 2016b). The remaining 17 plant species were common native species. No rare native species or nonnative, non-invasive species were observed. The number and type of species observed represent a reasonably diverse aquatic plant community, although the lake is dominated by two species, common water-nymph and fragrant waterlily.

The total aquatic plant cover measured during the August 2016 survey was 72 acres, which represents 45 percent of the total lake area. This area represents the maximum plant cover present during 2016 because plant growth was at or near the annual maximum on the survey dates. Plant cover is shown separately in Figure 4 for floating-leaved plants and submersed plants. Floating-leaved plants covered 31.7 acres and submersed plants covered 40.2 acres. Additional submersed plants were growing within a small portion of the floating-leaved plant area.

Aquatic plant density was highest closest to the shoreline, and lowest in the deepest portions of the lake (Figure 4). Aquatic plants were present from shore to nearly a 20-foot depth. The area with the densest vegetation was at the south end of the lake, although the northern end and western side of the lake also had large areas of dense plants.

Common water-nymph is by far the most abundant submersed plant in Hicks Lake. While this plant has become a nuisance in Hicks Lake because of its abundance, it is a critical plant for wildlife. The entire plant is eaten by waterfowl, and it is considered to be one of their most important food sources. Common water-nymph also provides habitat and shelter for aquatic insects and small fish. Common water-nymph was the dominant plant in all 10 grab samples and most visual observations. However, some areas of the lake displayed a diversity of plant species, particularly near the undeveloped southwest corner of the lake, as well as near Wanschers Community Park. In the southwest corner of the lake, plants such as common bladderwort (Utricularia vulgaris), western watermilfoil (Myriophyllum hippuroides), and whorled watermilfoil (Myriophyllum verticillatum) were locally sub-dominant. Near Wanschers Community Park, common waterweed (Elodea canadensis), quillworts (Isoetes spp.), and narrow-leaf bur-reed (Sparganium angustifolium) were found amongst the common water-nymph.

Fragrant waterlily, a Class C noxious weed, has also firmly established itself in Hicks Lake, especially in the southern end (Figure 4). When uncontrolled, the lily community forms dense single-species stands that take over the surface of the lake until they dieback in the fall. Mats of these floating leaves prevent wind mixing, and extensive areas of low oxygen and high temperatures can develop under the waterlily pads in the summer. Waterlilies can restrict

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 15 Figure 4. Hicks Lake Aquatic Vegetation Density Map, Lacey,20TH AVE SE Washington.

22ND CT SE Legend SHADYWOOD CT SE

Shoreline Submersed Vegetation 22ND AVE SE Stream Density

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LILAC ST SE Feet ´ 0 225 450 900

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lakefront access and hinder swimming and other recreational activities. They may also limit the growth of native floating-leaved plants such as spatterdock (Nuphar polysepala) and watershield (Brasenia schreberi). Both spatterdock and watershield were found growing within the fragrant waterlily, particularly in the south and southwest portions of the lake.

In previous years, curly-leaf pondweed (Class C noxious weed) and swollen bladderwort (state monitor weed) have been found in Hicks Lake. Neither were found during the 2016 aquatic plant survey. Two emergent Class C noxious weeds, reed canarygrass and yellow-flag were observed in a few locations along the shoreline. These plants were not abundant and did not appear to be causing problems.

5.2. TARGETED PLANT DESCRIPTIONS

Two plants, fragrant water lily and common water-nymph, will be targeted for control in the 2017 IAVMP. These plants are described below based on An Aquatic Plant Identification Manual for Washington’s Freshwater Plants (Ecology 2001), where descriptions of other plants in Hicks Lake may be found.

Fragrant waterlily is native to the eastern half of North America. It was most likely introduced into Washington during the Alaska Pacific Yukon Exposition in Seattle in the late 1800s. It has often been introduced to ponds and lakes because of its beautiful, large white or pink (occasionally light yellow), many-petaled flowers that float on the water’s surface, surrounded by large, round green leaves. The leaves are attached to flexible underwater stalks rising from thick fleshy rhizomes. Adventitious roots attach the horizontal creeping and branching rhizomes.

This aquatic perennial herb spreads aggressively, rooting in murky or silty sediments in water up to 7 feet deep. It prefers quiet waters such as ponds, lake margins and slow streams and will grow in a wide range of pH. Shallow lakes are particularly vulnerable to being totally covered by fragrant waterlilies. Fragrant waterlily spreads by seeds and by rhizome fragments. A planted rhizome will Fragrant Waterlily (Nymphaea odorata) cover about a 15-foot-diameter circle in 5 years.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 17

Common water-nymph is native to North America. This plant is sometimes referred to by its scientific genus, Najas. It is a completely submersed annual plant, although its fragments are often found floating unrooted throughout the water column. The leaves of common water- nymph are arranged oppositely on the stem, and cluster near the tips of the stems. The leaf blades are thicker where the leaves attache to the stem, Common water-nymph (Najas guadalupensis) and taper narrowly at the leaf tips. This characteristic can help distinguish Najas species from other submersed aquatic plants.

February 2017 18 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017

6. PAST MANAGEMENT EFFORTS

A summary of aquatic herbicide treatments undertaken at Hicks Lake through the Washington State permit program is listed in Table 3 (Ecology 2015). There have been four documented treatments of fragrant waterlily using the herbicide glyphosate on Hicks Lake since 2007.

Table 3. Summary of Permitted Aquatic Herbicide Use for Hicks Lake. Year Target Plant Chemical Used Amount (gallons)a Permit Number 2007 Fragrant waterlily Glyphosate 2.8 WAG994135 2010 Fragrant waterlily Glyphosate 1.4 WAG994135 2011 Fragrant waterlily Glyphosate 1.4 WAG994135 2012 Fragrant waterlily Glyphosate 1.4 WAG994135 a Application area is not recorded (Ecology 2015).

Discussion of past management efforts at the public meeting revealed that Hicks Lake one resident has organized treatments of fragrant waterlilies on the south side of the lake for the past 30 years. In 2015, a treatment of 5 acres of waterlilies using glyphosate was initiated, with the cost of treatment divided among six residences on the south side of the lake. Previously, waterlilies had been treated approximately once every six years to control regrowth between treatments.

Several lake residents noted at the public meeting that they have used rakes to remove submersed aquatic plants. No other past plant management efforts were known by the meeting attendants.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 19

7. AQUATIC PLANT CONTROL ALTERNATIVES

There are many methods used to control aquatic weeds. The methods chosen for aquatic plant control vary depending upon several factors, including: the species of aquatic plants targeted; whether the control goal is management or eradication; the cost of a method and availability of funds; the impacts to water quality and habitat; the safety and feasibility of a method; and support from lake residents. Control methods considered for Hicks Lake included:

• No action

• Chemical treatments

• Mechanical control methods

• Manual control methods

• Mechanical and diver dredging

• Biological controls

• Bottom screening

• Water level drawdown.

The full descriptions of each method, as well as advantages and disadvantages, permits, costs, and suitability for Hicks Lake, are summarized in Appendix B. Much of the information in Appendix B is taken directly from Ecology (1994), or from Ecology’s Aquatic Plant Management website (Ecology 2016a). Table 4 provides a summary of each method considered, its advantages and disadvantages, and suitability for Hicks Lake.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 21

Table 4. Aquatic Plant Control Options Considered for Hicks Lake. Category Method Description Suitable for Hicks Lake? Reasons for Suitability or Lack Thereof None No Action Nothing is done to control plant growth. No Recreational opportunities will continue to be impacted and possibly decline further Aquatic herbicide Chemicals are applied directly to plants or the lake to inhibit or restrict plant Yes: Cost-effective Chemical Methods growth. waterlily and water-nymph High level of control Hand-pulling Plants are removed by pulling out by hand. No Not cost-effective at a large scale for the plants in Hicks Lake Raking Plants are raked from the shore or dock using a rake attached to a rope. Yes: Equipment is inexpensive Manual Methods water-nymph Can be done by residents or volunteers Cutting Plants are cut from the shore or dock using a specialized tool. No Creates fragments that are difficult to collect and would spread water-nymph seeds Tool can be dangerous to use Mechanical harvesters Plants are cut and collected using a large barge-mounted machine with No Expensive at large scale conveyor. Rapid regrowth of waterlilies Mechanical weed cutters Plants are cut several feet beneath the water surface using a hand-held No Creates fragments that are difficult to collect and would spread water-nymph seeds. Mechanical Methods machine or boat without collection conveyor. Limited commercial services available Rotovators Plants are uprooted using a rototiller-like machine. No High cost Disturbs fish and habitat, and impairs water quality Mechanical dredging Sediment and plant material from the lake bottom is removed using barge- No High cost and difficult to obtain permits mounted suction equipment. Difficult to dispose of dredged material Dredging Methods Diver dredging SCUBA divers use a hose attached to a dredge to suck plants from the No Not suitable for the types of plants in Hicks Lake sediment underwater. Discharge impacts water quality Grass carp Sterile herbivorous fish are introduced to control aquatic weeds. No Requires outlet screening Biological Methods May remove all native plants and not suitable for waterlilies Very difficult to obtain permits Bottom screening A gas-permeable barrier is installed on the lake bottom that compresses Yes: Creates an immediate area of open water and can be installed around docks and swimming areas existing aquatic plants while blocking light to prevent further plant growth. waterlily Can control up to 100 percent of plants Other Methods Water level drawdown Lake levels are lowered for extended periods to expose nuisance plants to cold No No water control structure in place temperatures and dry conditions. Limited effectiveness in this area for targeted plants.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 23

8. AQUATIC PLANT CONTROL SCENARIOS

The aquatic plant management goal for the lake is to use an integrated approach to control nuisance aquatic vegetation to a low enough level to not impact recreation or wildlife. While it is often the goal of IAVMPs to eradicate invasive species and cease herbicide treatments, allowing the native plant community to self-manage, that is not the intent of this plan. Widespread eradication of these plant species could detrimentally affect water quality as well as create space for invasion by more invasive species. Further, eradication of fragrant waterlily requires a high level of effort and expense to achieve and maintain eradication because it is such a wide-spread and prolific plant. Native water-nymph on the other hand, is known to provide valuable habitat for fish and food for waterfowl. In fact, due to these recognized benefits of native plants, the aquatic plant management permit (Ecology 2016b) limits control of nuisance native plants to a maximum of 50 percent of the littoral region of a 160-acre lake. The total littoral area of Hicks Lake is 99 acres based on the lake area from the shoreline to a depth of 20 feet. Therefore, treatment of common water-nymph is limited to a maximum of 49.5 acres.

Due to these considerations and others, the goal of this IAVMP is to establish a maintenance level of control for both of the target plants that meets recreational goals using an integrated approach that minimizes the use of herbicides. Scenarios were considered for treatment of each plant that achieved low, moderate and high levels of control. Those scenarios were presented at meetings with the Hicks Lake LMD Steering Committee on October 17, 2016, and with all LMD members on October 26, 2016. The low control strategy targeted 10 percent of the targeted plants using manual methods, the moderate control strategy targeted 50 percent of those areas using herbicides, and the high control method targeted 100 percent of those areas using herbicides. The acres of plant coverage are shown in Table 5. Costs were estimated for each level of control and compared to the annual LMD budget of approximately $50,000. These scenarios are described in more detail below.

Table 5. Plant Coverage on Hicks Lake Total Lake Area 160.0 acres Lake Areas Total Littoral Area 49.5 acres Medium to High Density Submersed Plant Area Outside of Conservation Area 13.1 acres

Submersed Low Density Submersed Plant Area Outside of Conservation Area 21.5 acres Plant Areas All Submersed Plant Area Inside of Conservation Area 5.6 acres Total Submersed Plant Area in Hicks Lake 40.2 acres Floating-Leaved Plant Area Outside of Conservation Area 23.4 acres Floating- Leaved Plant Floating-Leaved Plant Area Inside of Conservation Area 8.3 acres Areas Total Floating-Leaved Plant Area 31.7 acres

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 25

Two herbicides were considered for use in this plan: glyphosate and diquat. Glyphosate will be used for continued treatment of fragrant waterlily. Diquat will be used for control of common water-nymph. Glyphosate was selected for continued control of fragrant waterlily because it has been effectively used in Hicks Lake and many other lakes in the region. Similarly, diquat was selected because it is one of the few herbicides that is known to be effective for common water- nymph, including a very effective treatment of nearby Black Lake in 2016 (Lake Stintzi, Black Lake Special District, personal communication, October 2016).

Both glyphosate and diquat are approved for aquatic use in Washington State based on environmental impact studies. As a result of these studies, there are many other herbicides allowed by the US Environmental Protection Agency (US EPA), but prohibited for use in Washington State. In addition, Thurston County separately assesses herbicide risks that apply only to applications performed by county staff for lakes managed by Thurston County. Thurston County considers glyphosate to have a high potential hazard for human toxicity and a moderate potential hazard for aquatic toxicity and environmental persistence hazard. Diquat is considered to have a high potential hazard for human and mammal toxicity, a high aquatic toxicity, and a high persistence hazard (Thurston County 2016a). As a result, neither of these herbicides are used by county staff, but both are allowed for use in Hicks Lake by a licensed commercial applicator. Full precautions will be taken during applications at Hicks Lake to ensure that herbicide levels do not exceed the amounts at which these hazards arise by not exceeding amounts specified by US EPA on the product label.

Both glyphosate and diquat are relatively inexpensive with application costs around $350 and $500 per acre, respectively. (Terry McNabb, Aquatechnex, personal communication, October 2016). These estimated per acre costs include two treatments performed a few weeks apart.

Plant control strategies were initially developed to control a range of water-nymph and waterlily areas. The maximum area where control was needed for each of the problem plant species was defined. Initial costs for water-nymph treatment scenarios described below included control of all submersed plants outside of the designated conservation area in the southwestern portion of the lake (Figure 5). The water-nymph control area was estimated to be 34.6 acres and was intended to include only areas of medium to high density submersed plants outside the conservation zone. Later, it was realized that the initial control area of 34.6 acres mistakenly included low density plant growth and that the area of medium to high density submersed plants outside the conservation zone was actually only 13.1 acres (see Table 5). The preliminary cost estimates for water-nymph treatment presented to the LMD in October 2016 and described below were based on an overestimated treatment area of 34.6 acres. Cost estimates for the selected action strategy presented to the LMD in January 2017 and described in Section 9 were based on the actual treatment area of 13.1 acres. Water-nymph treatment will be limited to a maximum of 50 percent of the total submersed plant area (40 acres) rather than 50 percent of the littoral area (50 acres) because a large portion of the littoral area will also be treated for fragrant waterlily.

The maximum control area for fragrant waterlilies was defined as the entire floating-leaved plant area, except for those plants located in the conservation area. This equates to 23.4 acres, or

February 2017 26 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 Figure 5. Hicks Lake Aquatic Vegetation Control Map, Lacey, Washington. 20TH AVE SE Legend 22ND CT SE SHADYWOOD CT SE Maximum fragrant waterlily control area Low density submersed aquatic vegetation (no control) 22ND AVE SE

Maximum common water-nymph AGATEcontrol CT SE 22ND AVEarea SE Conservation area Conservation area - Fragrant waterlily (no control) Conservation area - Common water-nymph (no control)

LILAC ST SE Shoreline Contour Parcel

SHADY LANE RD SE Feet TRILLIUM ST SE ´ 0 225 450 900

MAXINE ST SE K:\Projects\Y2015\15-06169-000\Project\Report\monitoring.mxd (11/14/2016)

CARPENTER RD SE

-5

25TH AVE SE -30

GWINN LN SE Wanschers Park -20

-35 -25

WDFW Boat Launch 27TH LN SE

-15

-10

HAZELWOOD LN SE

HICKS LAKE RD SE 30TH AVE SE

33RD AVE SE

74 percent of the total floating-plant area (31.7 acres). It is recognized that spatterdock and watershield occupy a relatively small portion of this area and will not be controlled, but the entire area was used for planning purposes. The aquatic plant management permit (Ecology 2016b) allows 100 percent control of fragrant waterlily because it is classified as a noxious weed. However, control of this entire area at one time would likely result in secondary impacts from large amounts of floating waterlily mats and may impact water quality from massive plant decay.

Preliminary costs for three levels of control were presented to the Steering Committee on October 19, 2016, and to the LMD on October 26, 2016. The low control strategy was more expensive than higher control strategies that relied upon herbicides due to the high cost of manual methods, and it did not meet the level of control desired by the LMD. The medium control and high control strategies were both within the LMD budget. The public expressed their desire for 100 percent control of both fragrant waterlilies and water-nymph, but recognized the potential impacts of controlling 100 percent of those plant areas in one year.

Preliminary annual costs for each level of control are presented in Table 6. Cost details are summarized separately for each IAVMP component below. In addition to water-nymph and waterlily control, annual costs were included for control of floating waterlily mats each year and aquatic plant mapping once every second year. The LMD would not incur costs for public education (coordinated by LMD volunteers with training by Thurston County staff and others), water quality monitoring (conducted by Thurston County staff under contract with the City of Lacey), or annual reporting (prepared by LMD volunteers). Total annual costs for IAVMP implementation were estimated at $73,750 for the low level, $18,745 for the medium level, and $33,490 for the high level. The LMD currently collects approximately $50,000 per year for aquatic plant management.

Table 6. Preliminary Annual Costs of Aquatic Plant Control Scenarios for Hicks Lake in Lacey, Washington. Low Control Medium Control High Control Management Activity (Manual) (Herbicide) (Herbicide) Water-nymph Controla $8,750 $8,650 $17,300 Waterlily Control $60,000 $4,095 $9,190 Floating Root Mat Control $0 $1,000 $2,000 Plant Survey $5,000 $5,000 $5,000 Public Education $0 $0 $0 Water Quality Monitoring $0 $0 $0 Annual Report $0 $0 $0 Totals $73,750 $18,745 $33,490 a Water-nymph control costs were overestimated because they included low density submersed plants for a total control area of 34.6 acres versus 13.1 acres for control of only medium to high density submersed plants.

To preserve some of the existing nuisance vegetation to preserve fish habitat, protect water quality, and meet Ecology’s permit standards, the Hicks Lake LMD Steering Committee identified a conservation area located in the southwest corner of the lake where recreational activities are

February 2017 28 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017

not impacted and no nuisance plants will be removed. Conservation areas are essential to the preservation of wildlife habitat, natural vegetation, and should be maintained as such to meet compliance with applicable federal, state, and local regulations. The areal extent of the conservation areas is also intended to retain a portion of 50 percent of the littoral zone, so that plant management activities can take place elsewhere. Figure 5 shows the location and extent of the conservation area selected by the Steering Committee. In addition, native spatterdock and watershield will not be controlled to retain natural floating-leaved vegetation for fish and wildlife habitat.

There are two components of the treatment plan, as well as contingency management methods, that are separately described below. Sustained control is the management objective for fragrant waterlily and native floating-leaved plants. Treatment would focus on maintaining access from the shoreline to the center of the lake. They represent the options presented to the Hicks Lake LMD Steering Committee and members.

8.1. NOXIOUS FLOATING-LEAVED PLANT MANAGEMENT

As summarized in Table 7, three levels of control for fragrant waterlily were presented to the Hicks Lake LMD in October 2016:

• Low level of control – The low level of control would use bottom barriers to eliminate fragrant waterlily in front of approximately 30 lots with the highest densities of fragrant waterlilies and the greatest hindrance to access. Under this strategy, approximately 3 acres would be covered by bottom barrier at an estimated cost of $60,000. Bottom barriers require maintenance and regulations require removal after 2 years. New bottom barriers could be added as funding allows, eventually controlling much of the lake’s waterlily population.

• Moderate level of control – This method would use glyphosate to control 100 percent of fragrant waterlily (excluding the conservation area) over a 2-year period; 50 percent of the area in Year 1 and 50 percent in Year 2. Within 2 years, the entire fragrant waterlily population on Hicks Lake would be treated, and small areas of regrowth would be treated in following years. The cost of treating fragrant waterlily with glyphosate is $350 per acre, and would cost approximately $4,095 for each of the first 2 years and less thereafter to maintain lake access. There are also costs associated with removal of floating mats of treated waterlilies that are addressed under the Contingency Management section of this IAVMP.

• High level of control – This method would control 100 percent of fragrant waterlily outside the conservation area with glyphosate. The cost of treating fragrant waterlily with glyphosate is $350 per acre, and would cost approximately $8,190 in the first year and less thereafter. There are also costs associated with removal of floating mats that might form that are discussed under the Contingency Management part of this IAVMP.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 29

Table 7. Fragrant Waterlily Management Options on Hicks Lake.

Level of Control Proposed Method Control Area Unit Cost Annual Cost Low (10%) Bottom Screening 3 acres (30 lots) $2,000/lot/year $60,000 Moderate (50%) Glyphosate 11.7 acres $350/acre/year $4,095 High (100%) Glyphosate 23.4 acres $350/acre/year $8,190

8.2. NATIVE NUISANCE SUBMERSED PLANT MANAGEMENT

As summarized in Table 8, three levels of control for common water-nymph were presented to the Hicks Lake LMD in October 2016:

• Low level of control – The low level of control would focus on manual methods of control. The two control techniques include the purchase of weed rakes and hand removal. The weed rakes could be used by LMD residents to control weeds on their own properties. The cost of two weed rakes would be $250 for a one-time purchase. Alternatively, the LMD could pay laborers for removal of common water-nymph by raking at an estimated cost of $250 per lot per year. This would cost $8,750 for 35 lots treated once each year.

• Moderate level of control – This method would control 50 percent of common water- nymph (excluding those in the conservation area) with diquat each year, focusing each treatment on the areas with the densest amount of common water-nymph. The cost of treating common water-nymph with diquat is $500 per acre, and would cost approximately $8,650 in the first year and less thereafter.

• High level of control – This method would control 100 percent of common water- nymph (excluding those in the conservation area) with diquat. Each year, the areas with the densest amount of common water-nymph would be treated. The cost of treating common water-nymph with diquat is $500 per acre, and would cost approximately $17,300 in the first year and less thereafter.

Table 8. Common Water-Nymph Management Options on Hicks Lake.

Level of Control Proposed Method Control Area Unit Cost Annual Cost a) Raking - Owner Unlimited (2 rakes) $125/rake $250 Low (10%) b) Raking - Contractor 3.5 acres (35 lots) $250/lot/year $8,750 Moderate (50%) Diquat 17.3 acres $500/acre/year $8,650 High (100%) Diquat 34.6 acres $500/acre/year $17,300

February 2017 30 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017

8.3. MAINTAIN LAKE HEALTH

There are several different plant control-related monitoring and evaluation needs that are recommended for Hicks Lake at any level of control. These include a plant survey every 2 years ($10,000 each survey), annual water quality monitoring (paid for by the City of Lacey), education of LMD members about lake health and control activities, and an annual evaluation of lake management activities (completed by LMD Steering Committee members). These annual assessments are vital for determining the effects of plant control on the lake, as well as for detecting new plant species that may cause future problems. The average annual cost for these activities is estimated to be $4,000 (for two plant surveys in 5 years).

8.4. CONTINGENCY MANAGEMENT

While this IAVMP addresses the issues that are currently affecting Hicks Lake, it is possible that other issues may arise over the course of the 5-year IAVMP time frame. It is important to consider contingency plans in case these issues require action. Such issues that may arise include the need to remove waterlily root mats and the introduction of new invasive aquatic species. Contingency management methods are described for control of: floating waterlily root mats resulting from decay of roots in large treated areas, newly introduced submersed noxious weeds, and existing emergent noxious weeds.

Waterlily Root Mats

• Low level of control – If only a small number of root (rhizome) mats arise, they may be incorporated into the conservation area or anchored in place, rather than be removed from the lake. Floating root mats can be dragged by a boat into the conservation area, and pushed through existing waterlilies and grounded on existing sediment. This method was effectively used by a lake citizen to move a small mat in 2016. Alternatively attached or free-floating mats may be anchored in place for approximately 2 years until they completely decay and sink to the lake bottom. Alternatively, the LMD may hire a contractor with a large boat to move numerous free-floating root mats. For example, the Long Lake LMD used an aquatic plant harvester to move numerous mats to an unused portion of the lake shoreline, and used a water pump and hose to break up large mats for easier transport.

• Moderate level of control – Should numerous large floating waterlily root mats become an issue, floating root mats can be dragged by a boat to the public boat launch and hauled off site by a contractor. This would require use of an excavator to transfer the mats from the lake shore to a dump truck and then transport the material to an appropriate disposal site, which may or may not include a disposal fee. In addition, permission and possibly a permit would be required from WDFW for use of the public boat launch.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 31

• High level of control – Dredging is a potential solution for removing root mats from the lake at a higher level of control and cost than the low and moderate control methods previously described. This option may also be used to remove mats before they float to the water surface or fully dislodge from the lake bottom, in order to increase water depth for access from shore to deeper waters. Two alternative dredging methods identified for the Barnes Lake LMD include use of an Aquamog or DinoSix, which are described in Appendix B. A dredging permit and shore staging area for dewatering and storage of dredging materials would need to be identified for either method.

New Noxious Submersed Plant Control

• All levels of control – If the lake becomes infested by a noxious submersed plant such as Eurasian watermilfoil (Myriophyllum spicatum) or Brazilian elodea (Egeria densa), then immediately use hand-pulling and/or an herbicide treatment to eradicate the infestation. Initial small infestations are much easier and less costly to control before they expand to several areas of the lake. Emergency funds are available through Ecology for treatment of early infestations of noxious plants.

Noxious Emergent Plant Management

• Low level of control – Noxious emergent plant management of plants such as Japanese knotweed, yellow-flag iris, and reed canarygrass, may be removed by citizens or a contractor by hand removal and/or bottom barriers to provide a low level of control.

• Moderate level of control – This level is anticipated to control approximately 50 percent of noxious emergent plant species. These species would be identified adjacent to the waterlily control areas, and treated from the lake by the contractor during the waterlily treatment. It would not include upland access and treatment of plants located far from the lake shoreline. The cost of treatment would be a relatively small addition the cost of the fragrant waterlily treatment.

• High level of control – This method would control approximately 100 percent of noxious emergent plant species. These species would be identified and mapped throughout the lake, and treated by boat and/or on foot depending on the extent of growth upland from the shoreline. The cost of treatment would be paid to the contractor in conjunction with the fragrant waterlily treatment, and would likely include more than the two site visits planned for waterlily treatment.

February 2017 32 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017

9. SELECTED ACTION STRATEGY & IMPLEMENTATION

9.1. ACTION STRATEGY

The Hicks Lake LMD Steering Committee desires and has budget for a high level of control of both common water-nymph and fragrant waterlily. Thus, the recommended action strategy presented in the draft IAVMP included control of all fragrant waterlilies and medium to high density water-nymph located outside the conservation area. However, the recommended action strategy for waterlily control did not cover 100 percent of the area in the first year for several reasons. First, a high level of control of the current population would likely result in an excessive production of floating waterlily root mats that would impact recreation and be costly to remove. In addition, a gradual approach to controlling nuisance aquatic plants was recommended to prevent issues with water quality from excessive plant decay and to preserve fish habitat.

Upon review of the draft IAVMP, the Steering Committee requested evaluation of a second strategy with a more aggressive approach to treat all fragrant waterlily in the first year. As a result, Action Strategy A and Action Strategy B were presented to the Hicks Lake LMD Steering Committee on January 17, 2017. Action Strategy A takes a gradual approach to treating fragrant waterlily at a rate of approximately one-third of the total area in each of the first 3 years. Action Strategy B only differs from Action Strategy A by treating all fragrant waterlily in the first year and including removal of nuisance floating waterlily root mats from the lake. After an assessment of both strategies, the Hicks Lake LMD Steering Committee selected Action Strategy A, due to its lower cost and gradual approach that will be beneficial to lake health.

Both action strategies are presented in the following sections, followed by an evaluation of potential water quality impacts of the two strategies. This IAVMP was designed to cover up to 5 years of treatment. The selected Action Strategy A will be evaluated and potentially revised on an annual basis, and the IAVMP may be updated to reflect new plant conditions or concerns after 5 years.

9.1.1. Action Strategy A

Action Strategy A takes a gradual approach to treating both common water-nymph and fragrant waterlily. Estimated costs of Action Strategy A, which is the selected action strategy, are presented in Table 9.

Action Strategy A includes the following elements:

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 33

• Common Water-Nymph Control – Treat all medium to high density growth of common water-nymph once every other year with diquat. (This treatment area is less than permit maximum of 49.5 acres based on 50 percent of the littoral zone.) One treatment of this area will be made at the beginning of the growing season (late May or early June), followed by a second treatment approximately one month later to treat any regrowth from seed germination. In Year 1 (2017) it is assumed that all 13.1 acres of the medium to high density growth of common water-nymph will be treated. The cost estimate assumes that in following treatment years (Years 3 and 5 [2019 and 2021]) up to 6.5 acres will be treated, based on a reduced amount of re-growth of this annual plant. It is possible that other native submersed plants may become dominant in the lake following the first year of treatment. For example, perennial plants such as pondweeds with extensive rhizomes often become dominant following treatment of annual plants such as common water-nymph. Therefore, treatments in Years 3 and 5 may target medium to high density growth of other native submersed plants, but still is expected to be limited to an area of 6.5 acres.

• Fragrant Waterlily Control – Treat one-third of fragrant waterlily (excluding the conservation area) with glyphosate annually for the first 3 years (approximately 8 acres each year from 2017-2019). Each treatment will involve an initial treatment, followed up by a second treatment a few weeks later to treat any plants that may have been missed because the pads had not surfaced or the herbicide had washed off the leaves. Treatment areas will be prioritized to provide property access to open water, as determined by the Hicks Lake LMD Steering Committee. Wherever possible, spatterdock and watershield will not be treated to retain these native floating-leaved plants for habitat. After 3 years, all waterlilies targeted for control will have been treated. Follow-up spot treatments of approximately 2 acres of fragrant waterlilies to maintain recreational access to open water habitat will take place in Years 4 and 5 (2020 and 2021).

• Waterlily Root Mat Control – In Years 2 through 5, the LMD will hire a contractor to haul floating waterlily root mats to anchor in the conservation area. It is estimated that this will take 2 days annually, at a cost of $1,000 per day.

• Aquatic Plant Survey – Survey and map submersed plant density and floating-leaved plant cover every other year in Years 2 and 4 (2018 and 2020). The survey will occur in late August or early September following those methods used in 2016 and including the mapping of emergent noxious weed locations. Survey results will be used to evaluate effectiveness of the treatments and refine the future action strategy.

• Water Quality Monitoring – Continue to monitor lake water quality on a monthly basis from May through October of each year following those methods used in the past. Water quality monitoring will be conducted by Thurston County under agreement with the City of Lacey at no expense to the Hicks Lake LMD.

February 2017 34 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017

• Public Involvement – Hicks Lake LMD members will participate in educational and other activities provided by the LMD Steering Committee each year as described in Section 10. These activities will be conducted by volunteers at no cost to the LMD.

• Evaluation Report – Prepare a report at the end of each year summarizing the year’s plant control efforts, presenting the herbicide contractor report, evaluating water quality monitoring results in comparison to previous years and plant control activities, summarizing LMD member education and involvement activities, and presenting the aquatic plant survey maps and evaluation performed once every 2 years. A brief report will be prepared by the Hicks Lake LMD Steering Committee for distribution to all LMD members in the winter of each year.

• Contingency Management – It is possible that new issues will arise during the 5 years covered by this IAVMP, such as floating waterlily root mat removal, the immediate treatment of new submersed noxious weed infestations, or the treatment of emergent noxious weeds. Based on the LMD budget of $50,000 annually and an average annual cost over 5 years of $12,280, there will be an average of $37,720 per year available for contingency management, should the need arise.

Table 9. Annual IAVMP Costs for Hicks Lake Action Strategy A. Management Activity 2017 2018 2019 2020 2021 Annual Average Water-nymph Control $7,000 $0 $3,500 $0 $3,500 $2,800 Waterlily Control $2,800 $2,800 $2,800 $700 $700 $1,960 Waterlily Root Mat Control $0 $2,000 $2,000 $2,000 $2,000 $1,600 Aquatic Plant Survey $0 $10,000 $0 $10,000 $0 $4,000 Water Quality Monitoring $0 $0 $0 $0 $0 $0 Public Involvement $0 $0 $0 $0 $0 $0 Evaluation Report $0 $0 $0 $0 $0 $0 Total $9,800 $14,800 $8,300 $12,700 $6,200 $10,360 LMD Budget $60,000 $50,000 $50,000 $50,000 $50,000 $52,000 Annual Contingency Fund $50,200 $35,200 $41,700 $37,300 $43,800 $41,640 Cumulative Contingency $50,200 $85,400 $127,100 $164,400 $208,200

9.1.2. Action Strategy B

Action Strategy B has many of the same elements as Action Strategy A, but it takes a much more aggressive approach to treating fragrant waterlily and removing floating waterlily root mats. Ultimately Action Strategy B was rejected due to its high costs and potential water quality impacts to the lake. Estimated costs of Action Strategy B are presented in Table 10.

February 2017 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017 35

The elements of Action Strategy A and Action Strategy B are the same concerning water-nymph control, aquatic plant surveys, water quality monitoring, public involvement, and evaluation reports. The strategies differ in the treatment of fragrant waterlily and floating root mat control, where Action Strategy B includes the following elements:

• Fragrant Waterlily Control – Treat the total waterlily area of 23.4 acres in Year 1 (excluding the conservation area) with glyphosate. Year 1 treatment will involve an initial treatment, followed by a second treatment a few weeks later to treat any plants that may have been missed because the pads had not surfaced or the herbicide had washed off of the leaves. Wherever possible, spatterdock and watershield will not be treated to retain these native floating-leaved plants for habitat. Follow-up spot treatments of up to 2 acres per year will follow in Years 2 through 5 to maintain recreational access to open water habitat.

• Waterlily Root Mat Control – Hire a contractor to haul up to 1 acre of floating waterlily root mats in Years 2 and 3 to the WDFW boat launch by boat or barge. It is estimated that the waterlily root mats will average 2 feet thick and comprise a total volume of 3,227 cubic yards. At the boat launch, the waterlily mats will be brought on shore using an excavator and dewatered to remove excess weight prior to transport to a disposal yard. The process is estimated to take approximately 10 days each year to fully remove the floating root mats. The cost of controlling 3,227 cubic yards of root mats is estimated at $50,000, based on $5,000 per day for towing, excavation, dewatering, and transport to a disposal yard. Root mat disposal is estimated to cost $60,000 each year, based on disposal of yard waste at the Thurston County Waste and Recover Center at Hawks Prairie at $45 per ton, and assuming 0.4 ton per cubic yard. In addition, initial planning and permitting is estimated to cost $10,000 in Year 2.

Table 10. Annual IAVMP Costs for Hicks Lake Action Strategy B. Annual Management Activity 2017 2018 2019 2020 2021 Average Water-nymph Control $7,000 $0 $3,500 $0 $3,500 $2,800 Waterlily Control $8,200 $700 $700 $700 $700 $2,200 Waterlily Root Mat Control $0 $120,000 $110,000 $0 $0 $46,000 Aquatic Plant Survey $0 $10,000 $0 $10,000 $0 $4,000 Water Quality Monitoring $0 $0 $0 $0 $0 $0 Public Involvement $0 $0 $0 $0 $0 $0 Evaluation Report $0 $0 $0 $0 $0 $0 Total $15,200 $130,700 $114,200 $10,700 $4,200 $55,000 LMD Budget $60,000 $50,000 $50,000 $50,000 $50,000 $52,000 Annual Contingency Fund $44,800 ($80,700) ($64,200) $39,300 $45,800 ($3,000) Cumulative Contingency $44,800 ($35,900) ($100,100) ($60,800) ($15,000)

February 2017 36 Hicks Lake Integrated Aquatic Vegetation Management Plan – 2017

9.1.3. Potential Water Quality Impacts of Action Strategies

Potential water quality impacts of the action strategies were assessed based on estimates of phosphorus loading into the epilimnion, or surface layer, of the lake from rapid decay of plants in the treated areas. The amount of phosphorus loading was compared to the amount of phosphorus in the epilimnion to determine if it would result in a substantial increase in the concentration of total phosphorus. The amount of algae (measured as chlorophyll a) and water clarity (measured as Secchi depth) are directly related to total phosphorus in lakes.

The amount of total phosphorus (TP) in the lake epilimnion was estimated to be 30 kilograms (kg) based on the epilimnion volume (to depth of 6 meters) and the average TP concentration of 12 ug/L in surface samples collected during the summer. Amounts of TP in the targeted plants were estimated from biomass measurements in Lake Lawrence (Thurston County) for common water-nymph (5 grams dry weight per square meter [g/m2]) and fragrant waterlily (30 g/m2) (Thomas et al. 1990), and an average phosphorus content of 0.2 percent for aquatic plants (Duarte 1992). All of the plant phosphorus was assumed to be entrained in the water upon treatment as a worst-case estimate of potential water quality impact.

If all 13.1 acres of water-nymph and 23.4 acres of waterlily were to be treated in one season, a potential algae bloom from total phosphorus (TP) loading could occur from the decay of treated plant species. The amount of TP in 13.1 acres of water-nymph is approximately 0.5 kilogram, or about 2 percent of the lake epilimnion TP. The amount of TP in 23.4 acres of waterlily contains 5.7 kilograms, or about 20 percent of the lake epilimnion TP. While treating all 13.1 acres of water-nymph is unlikely to trigger an algae bloom, increasing the amount of TP in the epilimnion by an additional 20 percent by treating the entire water lily area could be detrimental to lake water quality. In addition, it is possible that floating waterlily root mats may cause additional TP loading in the years following waterlily treatment. To avoid a significant TP loading event (increase of less than 10 percent) and potential algae bloom, it was recommended that only one-third of the waterlily area be treated each summer.

9.2. IMPLEMENTATION

Each year, the Hicks Lake LMD Steering Committee will evaluate the past year’s progress. At a minimum, the committee will need to evaluate the success of the management activities and make decisions about the next years’ treatment strategy. The Steering Committee will review annual evaluations from past years to determine if long-term aquatic plant management goals are being met. Other activities the Steering Committee may want to consider to manage the IAVMP are to: 1) actively monitor the herbicide applicators when they are on site to ensure proper areas are treated and to document herbicide quantities, and 2) coordinate with the City to ensure hired services, such as the herbicide treatments and aquatic plant surveys, are on track.

The following implementation timeline lays out the plan of the selected Action Strategy A for each of the first 5 years. This timeline will be adjusted annually as needed.

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Year 1 (2017)

• Treatment of approximately 13.1 acres of common water-nymph, representing all medium to high density growth of submersed plants outside the conservation area

• Treatment of approximately 8 acres of fragrant waterlily, representing approximately one-third of the total area outside the conservation area, and avoiding treatment of native spatterdock and watershield