The site is located at the east basin of the Union Bay Natural Area (UBNA) in Seattle, King County, Washington. The site is owned by the University of Washington and is bordered by: the Center for Urban Horticulture parking lot on the west, NE 41st Street to the north, Surber Drive NE to the east, and Lake Washington to the south. The basin generally has a south-southeast aspect. The elevation of the site varies from 44 feet to 20 feet above sea level. Lake Washingtons water level changes from 20 to 22 feet above sea level. It is controlled by the Hiram M. Chittenden Locks to maintain higher water levels during the summer boating season. Therefore the shoreline is seasonally variable.
The site contains a delineated wetland within the basin. There is evidence of an ephemeral stream through the lowest portions of the site running from north to south, however, the exact source has not been located yet. Across 41st St. to the northeast of the east basin there are delineated wetlands on this adjacent property that are probably hydrologically connected to the east basin. Since the construction of 41st St. separated these two areas of wetlands that used to once be an inlet along the shoreline of lake Washington water might move from north to south through subsurface flows below the road, but no known culvert connects them.
The site is on vashon till with the upland portions well drained. The lower portion of the site is modified land (mainly fill), which is saturated year round at the shoreline. There is evidence of erosion in the form of rills and gullies where the outfall of the parking lots storm water drains is located, along the western bank. The northern and eastern boundaries slope 40-50% and are steeper than the western boundarys 15-20%slope.
Existing Non-native vegetation
The northwest corner of the site was recently cleared of Rubus discolor (Himalayan blackberry). In the last year, the client has mowed, mulched and sprayed the blackberry thickets with herbicide in an effort to stop growth. The area should continue to be mowed for at least two years so the soil can be mostly free of the blackberry. The northeastern portion contains the remaining dense thickets of the blackberry. The southern portion of the site contains a mixture of native and non-native plants. The exotic species include unidentified turf grasses, Phalaris arundinacea (reed-canary grass), Lythrum salicaria (purple loosestrife), Ranunculus repens (creeping buttercup), Iris pseudacorus (yellow-flag iris) and Hedera helix (English ivy).
Previous Site Preparations and Planting
In the spring of 2001, four plots within the site were prepared with various treatments to test their effects on the Phalaris arundinacea (reed-canary grass). Landscape fabric and cardboard were used in combination with the existing mulch. The sites were then planted with a diverse selection of native species. There has been some weed growth and plant death within all of the plots. More evaluation is needed to determine what species are surviving in the existing conditions.
Goals and Objectives
The Center for Urban Horticulture wishes to restore a wetland buffer in order to increase native plant diversity, enhance wildlife habitat, and demonstrate use of appropriate native plant material in a public area.
Therefore, the major goals and objectives of this project are:
Goal 1: To increase native plant species and structural diversity and improve wildlife habitat in a disturbed wetland buffer located on the west bank of the east basin of the Union Bay Natural Area.
Objective 1-1: To continue to implement the management plan for invasive non-native plant species and to update and modify this plan as necessary.
Objective 1-2: To continue to design and install a structurally diverse and species diverse community of native vegetation initially characteristic of palustrine scrub-shrub and eventually characteristic of mature palustrine forested wetland communities of the Puget Trough ecoregion. New plots established in 2002 will enlarge and connect the 2001 plots.
Objective 1-3: To maintain the 2001 plots by removing invasive non-native plant species within them, renewing mulch layers, and enhancing them with new plant material.
Goal 2: To systematically monitor previous restoration efforts in the east basin in order to determine the most effective site preparation methods and most effective native species selected for various site conditions.
Objective 2-1: Use the 2001 monitoring plan to assess and record plant performance and continue to refine this plan as necessary, based on its feasibility.
Objective 2-2: Use the 2001 monitoring plan to assess and record site preparation and aftercare methods and continue to refine this plan as necessary, based on our experience using it.
Objective 2-3: Establish a long-term data management system for restoration work conducted in the east basin area.
Goal 3: To continue to nurture community understanding, accessibility, and participation, regarding the restoration work in the east basin, while also controlling human impacts in order to protect newly planted areas and sensitive shoreline habitat. (Community refers to Laurelhurst residents, University of Washington, and any other visitors to the site)
Objective 3-1: To improve and control pedestrian access to the basin by delineating and building a trail and providing interpretive signage describing the restoration process.
Objective 3-2: To develop both short-term and long-term volunteer involvement in the restoration of the east basin.
The determining factors of the planting scheme for Plot 4 include, hydrology, local climate, aspect, soil conditions, presence and extent of invasive species, project goals, and composition of the reference community.
Due to the seasonally fluctuating hydrological conditions within this site, and considering that maintenance and aftercare will be minimal, the selected species of plants have a relatively wide range of tolerance of soil moisture levels. A majority of the plant material used to restore the natural wetland buffer will consist of facultative trees and shrubs. Some herbaceous emergent plants could be planted later, after the non-native invasive species are somewhat controlled by an established native shrub layer.
All selected species are native species that are adapted to the local climate of lowland western Washington. Half of the species are not present on the site currently but are appropriate choices based on similar reference communities. Their addition will increase the diversity of species represented in the east basin. The other half of the selected species are already present on the site. New plantings of these species will enhance what already exists and are most likely to survive and thrive.
Most species will tolerate the southern exposure of this site. Although the two conifer species may not initially thrive in the high light conditions, they should be partially shaded within one year. In the long term, the addition of these tree species will provide structural diversity and more year-round shade as they mature.
The 2 ft. spacing of the shrubs is intended to be relatively dense in order to create a closed shrub canopy as quickly as possible that will shade out the invasive exotic species. Spacing guidelines are based on, Restoring Wetlands in Washington by Stevens and Vanbianchi, 1993.
Increased structural and species diversity, coupled with suppression of invasive exotic species, should improve wildlife habitat for native fauna. It will restore natural ecosystem functions that occur within forested wetlands in western Washington.
The client (CUH) is expected to provide the plant material. Some plant forms and species may be substituted to suit any confinements due to funding or availability.
Stevens, Michele and Ron Vanbiachi, 1993 Restoring Wetlands in Washington A Guidebook for Wetland Restoration, Planning and Implementation Washington State Department of Ecology Publication # 93-17, Olympia, WA 110 pgs.
The client will supply:
Mulching material will be freely donated and delivered by local arborists.
The mulch material must be of good quality, in order to avoid the introduction of invasive species.
(Please see Timeline for further details)
Our basic approach to this project involves a 3-phase plan. It is our intention to continue the work set in motion by the 2001 Project Team while adding new dimensions to the restoration plan.
During the site assessment we will utilize the 2001 Monitoring and Maintenance Plan for the east basin of UBNA to analyze the current status and success of Plots 1 and 2. The data will be recorded in a systematic procedure that is easily accessible for future use by CUH staff and subsequent project teams.
We will tag and document survival of plants in Plots 1 and 2. We will establish photo points for long term monitoring purposes. We will weed and reapply mulch to both plots. CUH staff will continue mowing the basin around Plots 1,2, and 4. CUH staff will reapply mulch to newly mowed areas. This step will address Objectives 1-1, 1-3, 2-1, 2-2, and 2-3.
Site preparation has already occurred through mowing, spraying, and mulching the invasive exotic species during the previous year. Throughout the portion of the basin that has previously been mowed and mulched there are sporadic sprouts of Rubus discolor (Himalayan blackberry) and Phalaris arundinacea (reed-canary grass).
At this time we encourage the CUH staff to initiate a second mowing around Plots 1, 2, 3, and 4, extending the mowed area to include the southwest bank of the east basin around Plot 0, and further to the east around the north end of the basin. Mulch should be added to all of the above-mentioned areas in order to prepare the site for restoration installations in 2004.
The areas within previous plots will be weeded manually and the areas outside the previous plots will be treated chemically if a second mowing is not sufficient for adequate suppression.
In order to prepare the site for this years installation, the mulch will be leveled in the planting area (to the north of Plot 1) using a bobcat or tractor to an approximate depth of 8-10. The mulch and mowing appears to have been effective in 2001 for suppressing the Himalayan blackberry and reed canary grass, because very little of either species is visibly resprouting in this area.
French Drain and Trail Construction
We will begin actual installation with the construction of the hardscape elements for two reasons. First, the French drain will resolve any erosion problems that could undermine subsequent trail construction and will help conserve soil resources and promote infiltration of stormwater. Secondly, people and small machinery could use the trail during the restoration installation process in order to confine traffic impacts.
We will dig a trench with a mechanized trench digger that is 60x1x1.5from the storm water outfall following the existing slope. A second trench that measures 30x1x1.5 will align perpendicular to the first trench forming a T. (See site maps) We will line the trenches with landscape fabric and large coarse gravel or small river stone 6deep, connect perforated 8 10 PVC pipe to the outfall pipe, and form a T using appropriate connectors. We will cover the pipe with 6 of gravel, wrap landscape cloth over gravel and then fill with soil to grade. (See site map)
We will improve the pedestrian access to the basin by installing a gravel pathway that is consistent in dimensions and design with other UBNA trails. It will begin from 41st St. and lead past Plots 1, 2, and 4 and then simply terminate, for now, just south of Plot 1. We will delineate the trail with stakes and ask CUH staff to grade the trail bed and apply gravel to the trail. This step addresses Objective 3-1. 9 (See site map)
We will install new and improved interpretive signage describing the experimental, scientific nature of the restoration plots that will encourage community understanding of the restoration project.
We will collect local cuttings of Salix, Cornus and Populus, to be used as live stakes. We will order any remaining plant material as soon as approval can be sought.
Plots 1 and 2 will be supplemented with new plant material to replace mortality.
A dense planting of appropriate native tree and shrub species will connect Plots 1 and 2. This newly established area will be called Plot 4.
(See Planting Plans for trees and shrubs)
Live stakes, bare root and container plants will be planted into un-amended existing soil. All plants will be watered in upon planting. Herbivory has apparently not been an issue in the past, so no protective fencing materials for this purpose is planned. However, it might prove useful to protect the site from human impacts, given the enhanced human access of a new trail.
Monitoring plan development
Eventually, data from this new test area (Plot 4, 2002) will determine the necessity of waiting 2 full years before installing restoration projects in areas heavily infested by blackberry. We will develop a new monitoring plan for the newly established Plot 4 and integrate this with past monitoring plans by revising them if necessary. This step addresses Objectives 1-1 and 2-3.
We will reestablish contact with the Laurelhurst community through a public presentation at one of their community meetings. Educational materials may also be presented to the Laurelhurst community on a regular basis, using the neighborhood newsletter. A regular feature could be titled, Whats new at the CUH restoration site? Presentations to the local schools will encourage a reconnection with the project, establish long-term involvement and provide volunteers for the planting and maintenance portion of the project. Through these presentations we will attempt to secure volunteers from the Laurelhurst community and local schools to assist with the installation of Plot 4 and to help maintain Plot 0, located at the south end of the basin. We will offer a volunteer day on Earth Day 2002 where volunteers will receive training in proper methods of planting and weed removal.
CUH staff will continue mowing and mulching the south end of the basin, outside of Plot 0, in preparation for future restoration projects by UWREN groups.
Addresses Objectives 1-1, 1-3, 3-2
Monitoring and Maintenance
The Spring 2002 Project is the second restoration effort in the UBNA East Basin in a series of implementation projects over many years. The restoration efforts completed in the first two years are to be considered experimental, and in no way to be considered a complete restoration effort. Four plots were installed on the site in 2001; the focus of 2002 monitoring efforts will be to systematically monitor those plots in order to determine the most effective site preparation methods and most effective native species selected for various site conditions. We will utilize the 2001 Monitoring and Maintenance Guidebook for initial monitoring efforts, refining the plan as necessary, based on its feasibility. A long-term data management system will also be developed for future restoration work conducted in the east basin area.
Due to the extent of disturbance on the site and the maintenance necessary to oppress the non-native invasive species on the site, the success of achieving the overall goal to restore native biodiversity and improve wildlife habitat can only be achieved in future years and in conjunction with future implementation. At present, what is applicable to be considered in the monitoring and maintenance of the four-implemented plots will be primarily focused on the vegetation, both the native species installed and the non-native invasive species present. Specific numbers or target percentages are not essential in this project because of its experimental nature; therefore the monitoring and maintenance goals are based on descriptive monitoring through inspection (what is working and where). General maintenance tasks are intended to promote plant survival and suppress non-native invasive species.
The long-term data management system will include items such as a folder for storage of hard copy project information, including monitoring and maintenance field forms and records, and all project plans in entirety. Reports and forms will also be provided in electronic form, along with a running Excel database of monitoring information that can be entered by the client and/or volunteers following fieldwork. A GIS project has also been compiled for the site, which includes data from the City of Seattle, and GPS data collected by the group. The GIS project can be used in the future to track maintenance efforts, including the locations of newly mowed areas, and plant movement, including areas that are being invaded by blackberry. The baseline GIS data that we are providing can be used for numerous applications, depending on the experience of the user.
The Student Project Team is responsible for maintenance and monitoring through June 8, 2002. Our client, Fred Hoyt, manager of facilities and grounds at the Center for Urban Horticulture and Union Bay Natural Area, assumes responsibility following the Student Project Team, and will be presented with this Monitoring and Maintenance Plan with tasks beginning June 11, 2002.
The Monitoring Plan for the Spring 2002 Project covers the next 5 years. As other projects are implemented in the East Basin affecting the Spring 2002 Project, or if unforeseen circumstances warrant for a longer monitoring period, it is the client's responsibility to assume an adaptive management approach. The following elements will be considered in the monitoring strategy: 1) vegetation - plant survival rates, overall species assessment per plot, and growth rates; 2) soil moisture; 3) wildlife use; 4) herbivory; and 5) human impact.
Vegetation monitoring will focus both on previously planted materials and non-native invasive species. Baseline data for the total number of species planted per plot has been provided in Appendix A of the 2001 Monitoring and Maintenance Guidebook with forms for annually recording species counts over the next 5 years. As important as overall survival data will be general information on species vitality and adaptability to specific plots, recording which species are doing well on which plots. A general comment form for recording overall species assessment information is provided in Monitoring Forms. Overall species assessment will be recorded and will include species vitality and adaptability to specific plots. This can include visual estimates/assessments of average height or canopy cover, overall health of species, and competition factors. Planted species will be labeled with metal tags to assist with monitoring efforts. Once plants have established, the tags will also be a useful tool for community understanding of the experimental techniques taking place on the site. For a visual record, fixed photo monitoring points will be established.
Photo Monitoring Points
Photopoints are landscape or feature photographs retaken each time from the same spot and filling the same frame so that differences between years can be compared. Photographs of general habitat can help monitor changes in plant cover, weed invasion, and disturbances. Plant height, flowering effort, plant size, and levels of herbivory are some of the conditions that can also be illustrated with photopoints. Baseline photos were taken in May 2001, however instructions for further duplication were not provided. We will make an effort to duplicate the photos, and if successful, we will have two subsequent years of photo documentation. Annual photo monitoring will be scheduled in May of the following years. A digital camera will be used to establish the photo monitoring plots. Photos will be taken at different angles using a tripod to improve photo quality and help to maintain the camera at a specific height. Three to four frames of the same picture should be taken. Record frames (a picture of a clipboard with date, time of day, and location) should be used when changing location, or film to ease with photo organization and identification. Once photopoint locations are determined, a map will be produced with symbols such as cent; which illustrates both the photopoint and the direction of the photograph. Permanent markers will also be used to mark photopoint locations to ease in the location of the points, as long as they do not interfere with future maintenance activities. A field form for keeping a photo log is included in Monitoring Forms.
2. Soil Moisture
Standardized testing of soil moisture will be recommended to the client. Changes in the surface water-ground water interface can affect ground water levels and water contributions to the river that may be critical to the survival of aquatic, marsh, and riparian terrestrial ecosystems (Barnard and McBain,1994). Due to the fluctuating lake level, we recommend the client gain a better understanding of wetland system changes throughout the site.
Piezometric tubes will be positioned in various locations throughout the site for future point-in-time sampling of substrate permeability in the hyporheic zone. Piezometric tubes, which should be at least 1/2 inch pvc pipes (to avoid capillary effects), will be driven into the ground. A piezometer can be inserted into the pipe, and measurements of groundwater level and permeability can be taken. It is our understanding that the client has access to a piezometer, if he chooses to pursue the monitoring.
3. Wildlife use
At this point, wildlife monitoring is being suggested as anecdotal. Concentrated monitoring at this time is not appropriate with the limited resources of the client. No specific wildlife species have been targeted, rather, plant species that have been chosen should eventually provide a food source and/or habitat structure for birds and small mammals. Specific wildlife monitoring could be the focus of future project implementation.
Deterrent systems for herbivory have not been installed on any of the four plots, and should be determined and implemented only if the need arises after regular inspections. There has been no sign of herbivory to date, although further monitoring of individual health/mortality may result in other methods as seen necessary by the client.
5. Human impact
With the installation of a public access trail, monthly site inspection should be conducted for human disturbance and impact. This should include inspecting for trampled plants, theft, or garbage within the plots and throughout the site.
Following is a table, which summarizes the above discussion on monitoring:
Restoration Site Monitoring Elements
A five-year maintenance program is outlined in this document and will be the client's responsibility. The maintenance program will include weeding, mulching, herbicide use, regular inspections for herbivory and invasion by undesirable plant species, mowing of blackberry around all four plot peripheries (until blackberry abatement is sufficient for native plant installation), and recommended in-planting and replanting for losses due to mortality. Since the suppression of non-native invasive species is a critical component and will be a key component to the success of the UBNA East Basin Project, the 2001 Project group included a comprehensive discussion of invasive species present on site and a weed management plan.
1. Plant Mortality
Some plant mortality is expected. As mortality is monitored and openings are created in the plots, the client should replace with individuals matching onsite environmental conditions. For following years, an annual survival inventory (see form in Appendix A) should be conducted in the spring with subsequent plantings determined and installed to replace mortality. If subsequent monitoring indicates that additional plantings are required, the client should determine the type and number of additional plantings.
In-planting is recommended annually in October until no longer seen as necessary and dependent upon client's resources. This should include a modest planting of species which should do well in sunlight. A more complete planting may be conducted in 2003 following the creation of some shade with 2001 and 2002 plantings. These plantings should be determined by the client given proper consideration of the environmental conditions on the site at the time. In-planting is dependent on resources available to the client and client's determination of need.
A species list in Appendix D of the 2001 Monitoring and Maintenance Plan indicates appropriate species for shade planting in years 3-5.
Mulch has been applied to all four plots to reduce soil water evaporation during dry periods and on previously mowed blackberry areas to assist with blackberry suppression. The client is advised to replenish a 4 to 6 inch layer of mulch in the plots in January (or sometime during the slower winter months) and on an annual basis thereafter for the first five years. Contingency plans may require mulching until vegetation is mature and organic leaf layer is existent. Monitoring for spot mulching is also recommended throughout the year to keep coverage around plants.
4. Conditions of Installation
Physical structures on the four installed plots are minimal. Bamboo stakes and twine have been used to delineate the plots, and this should be maintained as long as seen useful for plot location in regard to mowing of the remainder of the area, and as seen useful in deterring human impact. Colorful flags should be placed on the stakes, for further recognition once mowing activities begin. The landscape fabric on Plot 1 should be kept covered with mulch, and should be removed in 5 years or when 50% of shade cover is realized. Signage should be maintained or replaced if condition deteriorates or signage is vandalized.
5. Invasive Species
Invasive species that interfere with management goals
Himalayan blackberry (Rubus discolor) has successfully invaded this disturbed wetland buffer and is the most dominant species on the site. Throughout the site, blackberry is growing so densely that establishment of native species will be impossible if control is not established.
Reed canary grass (Phalaris arundinacea) is well established and has formed monotypic stands in the wetter areas of the site. In order to establish native species on this site, control must be established.
Morning glory or hedge bindweed (Calystegia sepium) occurs throughout the site. In areas where control practices are being practiced on blackberry and reed canary grass, bindweed seems to be more aggressive with less competition. The concern is that if the weed is not kept in check, it will choke out the new native plantings on the site.
Turf grass (Graminoids) occurs in patches on the west portion of the site. The aggressive nature of the rhizomes will outcompete native plant material that has been planted for water, nutrients and space.
General weed management plan
The focus of this restoration is suppression of invasive species and the establishment of wildlife habitat. Plants selected for the site have been chosen not only to provide habitat, but also to shade out invasive plants such as reed canary grass and blackberries. Future plantings will help to prevent further establishment of the invasive species located on the site. Priorities will be set according to real and potential threats of each species to the establishment of native plant species. Inspections for the detection of new invasive species should be ongoing. Control of the invasive species will take place only when it is determined that the species will do more harm by remaining on the site. This restoration project will use an adaptive management strategy.