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HomeMy WebLinkAboutSpecial Report (017)22 Acre Parcel, off the Duckabush Road Buffer Enhancement Report A Prepared By: PPLIED E ~IVIRONMENTAL S ERVICES, INC. 1550 Woodridge Drive SE Port Orchard, WA 98366 September 9, 2002 Buffer Enhancement Table of Contents CHAPTER 9.0 10.0 11.0 12.0 13.0 14.0 1.0 LOCATION 2.0 PROJECT DESCRIPTION 3.0 SCOPE 4.0 GENERAL SITE DESCRIPTION 5.0 EXISTING WETLAND CONDITIONS 6.0 PROPOSED PROJECT 7.0 BUFFER ENHANCEMENT PLAN 8.0 GENERAL HYDROLOGIC PATTERNS AND SITE SOILS AFTER BUFFER ENHANCEMENT AND TOPOGRAPHY WETLAND BUFFER FUNCTIONS BEFORE AND AFTER ENHANCEMENT CONSTRUCTION & PROJECT SCHEDULE GENERAL PLANTING INFORMATION MAINTENANCE MONITORING PROGRAM CONTINGENCY PLAN REFERENCES FIGURES FIGURE 1 VICINITY MAP AND TOPOGRAPHIC MAP FIGURE 2 SITE PLAN FIGURE 3 IDENTIFICATION OF ENHANCEMENT AREA AND PLANTING PLAN TABLES PAGE 1 1 1 1 4 4 5 8 2 3 9 8 10 10 11 11 12 TABLE 1. ENHANCEMENT VEGETATION FOR THE DUCKABUSH PROPERTY 6 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan 1. LOCATION Applied Environmental Services, Inc. (AES) performed a wetland delineation, and this subsequent buffer enhancement plan on a 22 acre parcel of property located at off the Duckabush Road one mile up the Duckabush Road immediately west of the power line easement in Jefferson County, Washington. This property lies within Section 17, Township 25N, and Range 2W WM in the state of Washington. The local jurisdiction is Jefferson County. Figure 1 illustrates the project vicinity. 2 PROJECT DESCRIPTION The wetland delineation report (submitted in August 2002) and this wetland buffer enhancement plan has been prepared in association with a Site Plan Approval Advance Determination. (SPAAD) request for a proposed single family residence on the property. This SPAAD is important to the proposed buyers due to the existing critical areas found onsite. As part of the site development planning process, the prospective purchasers request county approvals of locations of pertinent site features which include: · primary and secondary drain field, · existing road layout and configuration, · proposed well location and most importantly, · a residence footprint large enough to accommodate a permanent residence, a three car garage and driveway on the highest terrace in the vicinity of the existing site structures. No specific building plan exists at this time. The enclosed site plan (Figure 2) includes a schematic of these features. 3 SCOPE The scope of this buffer enhancement report is to fulfill the requirements of the Jefferson County Unified Development Code, Section 3 Land Use Districts Subsection 3.6.9 (6) Reducing Buffer Widths. 4 GENERAL SITE DESCRIPTION This 22 acre property is intriguing due to its existing critical areas and topographic features. Its dominant feature is the 800+/- footage of Duckabush River frontage along the southern and western edges of the property. There are two Category I wetlands (B and C) and a small non-jurisdictional Wetland A surrounding the existing homestead. There is a well maintained dirt road (termed Valley View Lane on some maps), there are two power poles, one with a meter (turned off), one small standing shed, one partially erect barn with chicken coop, one larger fallen barn and a concrete foundation for a home (Figure 2). There are three distinct terraces: one closest to the river (within the floodplain), an intermediate bench, an upper bench with the dwelling units, then the steep slope leading to adjacent parcels and the Duckabush Road. Applied Environmental Services, Inc. 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan 122059.000. W TOPO! map printed on 06/29/02 from "duckabush.tpo" and "UntiUed.tpg" 122°58,000' W 122°57.000, W WGS84 122056.000. W 122059.000' W' 122058.000' W 122°57.000' W WGS84 12~°56.000' W TNFN Primed ~m ~! ~ I N~ ~p~ Ho~ (~.to~.~ FIGURE 1. VIC~Y MAP ~D TOPOG~PHIC MAP Applied Environmental Services, Inc. 2 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan 5. EXISTING CONDITIONS WETLANDS As stated in the Duckabush Wetland Delineation Report (AES 2002), Wetland B and C are pristine wetland systems containing mature conifers and hardwoods with a well developed understory of native high habitat value vegetation. Both are situated at the toe of a significant slope and are large in size. Wetland B is directly connected to the Duckabush River near the western edge of the property. Following the classification specified by Jefferson County Unified Development Code, Section 3, Land Use Districts. Wetland B is a Category I wetland with a specified buffer width of 150 feet. Wetland C is located on the eastern edge of the property beginning and ending offsite. The flagged portion of Wetland C is at the toe of the slope that borders the existing, well developed road. Wetland C, within the property boundaries, remains intact with a full canopy of cedars and hardwoods. Wetland C is also a Category I wetland with a specified buffer width of 150 feet. Wetland A is a small spring fed system originating on a shallow slope of the hillside. This wetland, while also containing some mature hardwoods, was maintained by previous landowners. The wetland boundary is the well developed road along the south. The water for this wetland originates from multiple locations along the slope, not a single point source. Wetland A is classified as a Category 111 wetland, yet non-jurisdictional due to its small size (approximately 5550 sO. This wetland, while non-jurisdictional, from a wetland classification perspective, will be left alone as one of the many site amenities. Since this wetland will be left intact, a 75 foot from surface water buffer will be honored for placement of the onsite drainfield (See Figure 2). The lower bench of this property has been identified as floodplain but contains no associated wetlands within the boundaries of the subject parcel. 6. PROPOSED PROJECT As shown on Figure 2 the applicant proposes to place the site development features on the upper bench of the property previously used as the homestead site. The proposed well location, and 100 foot wellhead protection zones are identified. The primary and reserve drainfields, for a three bedroom house, are shown on the plan with a cross hatch pattern. Each cross hatched area is approximately 4000sf. Both the primary and reserve drainfields will utilize alternative septic systems (Glendon system or equivalent) when designed. Soil pits taken in these areas support this type of treatment system. See the previously submitted report by Alternative Designs (August 2002) for further details. Alternative systems, by design, take up less physical space than a conventional system, they typically require pre-treatment and a pump system and finally must be at least 75 feet away from surface water. The system will also be 10 feet away from the buildable area. As shown on Figure 2, all these conditions are met. The area will be vegetated with shrubs when complete. Applied Environmental Services, Inc. 4 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan A house, garage and greenhouse area (encompassing approximately 4800sf) are shown on Figure 2 with a diagonal hatch pattern. A house plan has not been prepared at this time. Current thoughts on this topic include a three bedroom home with a three car garage. The site plan illustrates this concept. This will be a full time retirement home when complete so the applicant is planning on placing all critical dwelling rooms and amenities on a single level. As time and mobility dictates, the upper floor will be functionally isolated from the main floor. The existing road into the property will be utilized. The driveway, close to the garage will be paved. Approximately 1500sf of new impervious surfaces will be created with the driveway. Total new impervious surfaces will be approximately 6300sf. The septic system, of approximately 4000sf will be revegetated with shrubs when complete. The 'collapsed building' of approximately 1200sf (considered impervious surface) will be removed and revegetated. As with many old homesteads, much trash, derelict equipment and structures have accumulated on the property. Through the course of this development, these will be removed. Items that have been found to date include a concrete pad of the old homestead by the shed and power pole of approximately 1000 square feet. The shed of approximately 100sf will be removed and become part of the home. An unburied diesel oil tank, various fences, wire bundles, etc that are in the buffer and wetland will be removed offsite. Subtracting old and removed impervious surfaces from new impervious surfaces yields a net increase of impervious surfaces of approximately 4000sf. Figure 2 also shows that new site structures are at least 75 feet away from any wetland boundary. Buffers for Category I wetlands are 150 feet. This plan illustrates a 50% reduction of the buffer in the vicinity of the home. 7. BUFFER ENHANCEMENT PLAN Wetland and buffer mitigation has become necessary as developable land becomes increasingly scarce. For purposes of this plan, it has been estimated that the net expected buffer impact area to be approximately 4,000 square feet of Wetlands B and C. Environmental goals and objectives and a monitoring plan have been developed. Goals & Objectives The goal of this plan is to enhance buffer habitat of Wetlands B and C. · Install ten bird houses and ten bat boxes through out the remaining buffer areas on both Wetlands B and C. · Remove and control invasive vegetation such as various species of blackberries throughout the site. There is approximately 15,300 square feet of Himalayan blackberry on the site in the vicinity of the old homestead within the buffers of Wetlands B and C. This is an enhancement ratio of over 3: 1. · Remove collapsed building (west end of homestead area) and revegetate area. This area is approximately 1200sf. Applied Environmental Services, Inc. 5 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan Remove abandoned equipment and trash which includes concrete structures, fencing, wire, unburied oil tank etc. Planting Information Tree and shrub species selected for the buffer enhancement plan are listed below in Table 1. Table 1. Enhancement Vegetation for the Duckabush Property Item Common Name I Scient~ficName Size I Number I Spacing Trees: Western red cedar Thuja plicata 5 gallon 3 40' oc Sitka Spruce Picea sitchensis 5 gallon 3 40' oc Apple Pyrus malus 5 gallon 3 40' oc Crabapple Pyrusfusca 5 gallon 2 40' oc Pear Pyrus communis 5 gallon 2 40' oc Plum Prunus subcordata 5 gallon 2 40' oc Cherry Prunus avium 5 gallon 2 40' oc Shrubs: Nootka rose Rosa nutkana 1 gallon 44 4' oc Salmonberry Rubus spectabilis 1 gallon 28 4' oc Willow Salix spp. stakes 33 4' oc Raspberry Rubus idaeus 1 gallon 23 4' oc Blueberry Vaccinium sp 1 gallon 38 4' oc oc = on enter Thuja plicata Western red cedar is a sweet-smelling, coniferous evergreen tree that likes moist soil but can also survive in drier habitats. It grows slowly, but it can grow to heights of between sixty and two hundred feet. As it grows, its crown becomes open and its lower branches droop. Clusters of small brown cones grow at the ends of the branches. Instead of needle leaves, it has tiny scales set snugly on the branches and is resistant to rot and fungus (Polar and MacKinnion et al. 1994). It provides protective and nesting cover for wildlife and twigs and foliage for browsers. Its small cones contain seeds attractive to birds and small mammals (Martin et al. 1951). Picea sitchensis: Though more common on the coast, this swampland conifer is well adapted to wet stream side conditions. Sitka Spruce grows quickly and is an easy victim of bud-eating insects. Applied Environmental Services, Inc. 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan It has bristly, sharp, bluish-green needles on dropping branches and medium-sized reddish cones with irregular scales. Deer, rabbits, and grouse eat its twigs and leaves, and small mammals and birds eat its seeds. It provides good nesting habit and winter shelter for birds (Thurston County Conservation District). In pure or mixed stands, often on moist, well-drained sites such as alluvial floodplains, marine terraces, headlands, recent glacial outwash, avalanche tracks; also on old logs or mounds on boggy sites; typically at low to middle elevations, but reaching timberline on the Queen Charlotte Islands and the most maritime parts of southeast Alaska (Pojar and MacKinnon 1994). Malus fusca: Western crabapple is large scrub or small tree, is characterized by attractive white or pink flowers in the spring, small yellow to deep red fruits in the summer, and bright red foliage in the fall. It fruits are eaten by many different birds, and are edible to humans as well. This plant often forms thickets (Thurston County Conservation District). Moist woods, swamps, edges of standing and flowing water, upper beaches, often fringing estuaries; low to middle elevations the length of our regions (Pojar and MacKinnon 1994). Other Fruit Trees Other fruit trees, apples, pears, cherries and plums are included in this enhancement plan. These trees will provide structure, shade and fruit to the residents of the site. The habitat value and diversity provided by the fruit trees exceeds that of the patches of invasive Himalayan blackberry. Rosa nutkana Nootka rose is a deciduous shrub that has a very good soil-binding root structure. This rose grows well in a variety of habitats. It has a tendency to be spindly and can reach a height of ten feet. Large, solitary pink flowers which produce big purplish, pear-shaped rosehips are typically present at the branch tips and a pair of large prickles occur at the base of each leaf (Pojar and Mackinnon et al. 1994). Once established, the Nootka rose will spread by underground suckers to form thickets that provide excellent cover for birds and small mammals. Rubus spectabilis: Salmonberry is a 4 to 8 ft tall perennial shrub, that spreads by rhizomes to form thickets along streams and in forested swamps dominated by deciduous trees (Department of Ecology 1993). Moist to wet places (forests, disturbed sites), often abundant along stream edges, avalanche tracks and in wet logged areas; at low to subalpine elevations (Pojar and MacKinnon 1994). Salix spp. Willows are the most common trees used for stream revegetation. They are easily established from cuttings without added root hormone, and rapidly produce luxuriant growth. Willows have excellent soil-binding qualities and provide excellent browse for deer, elk, smaller mammals and grouse. They often hang over the water, providing leaves Applied Environmental Services, Inc. 7 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan and insects which drop from their branches and support the aquatic food chain, and shade, which modulates summer water temperature. Most willows tolerate seasonal flooding. Vaccinium ovalifolium or spp. And Rubus idaeus Blueberries and raspberries are added to the enhancement plan to again increase the diversity, habitat structure and food value of the vegetation species onsite. Raspberries will produce fruit in early summer and blue berries in the fall (Thurston County Conservation District, Pojar and MacKinnon 1994). These species are currently on or adjacent to the site and native to Jefferson County. Native trees and shrubs were chosen to avoid spreading non-native vegetation. All plants used for enhancement will be healthy and disease free. All trees will be planted randomly on fourty-foot centers to allow the plants the space to grow to maturity, within the targeted buffer enhancement area. Shrub species will also be randomly planted in clusters surrounding these trees. All plants will be installed with controlled release fertilizer. Subsequent fertilizer application will be done as conditions warrant and only in an environmentally sound manner. After construction, a photo record will be sent to Jefferson County and other jurisdictional agencies notifying them the enhancement project is complete. The photos will include descriptions of the final site configuration, plant types, and planting locations and will be submitted within thirty days of site revegetation. This "As Built" plan and first monitoring event should begin the three year monitoring period. 8. GENERAL HYDROLOGIC PATTERNS AND SITE SOILS AFTER BUFFER ENHANCEMENT AND TOPOGRAPHY Following homesite development and buffer enhancement, hydrologic patterns of Wetlands B and C are expected to remain unchanged. Site soils will remain unchanged. The topography of the property will not significantly change after the home is built. 9. WETLAND BUFFER FUNCTIONS BEFORE AND AFTER ENHANCEMENT Functions of the wetland buffers are numerous and varied on this site. Most are very good but invasive species are beginning to tale over in four distinct areas onsite. Four distinct patches of Himalayan blackberry are currently present on the site. One clump of approximately 5400 square feet is near the existing chicken coop. A second substantial blackberry patch is located east of the cherry tree identified on Figure 3. Its size is estimated at 2700 square feet. The third grouping is south of the cherry tree on the slope at approximately 2000 square feet. The last substantial blackberry patch, by far the largest, is located on the floodplain as shown on Figure 3. Its size, within the property boundaries, is estimated at 5200 square feet. Total Himalayan blackberry within the buffers of Wetlands B and C, within the property boundaries is approximately 15,300 square feet (0.35 acre). Applied Environmental Services, Inc. 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan LCaLL^PSED ~3 CL RO~D" 61 SHED oPP Symbol Species Fruit trees ,A, Sitka Spruce II Cedar ~ Salmonberry P,. Nootka Rose 'v,/ Willow '-",.- Raspberries //// Blueberries k,\\X Grass ~'~ Invasive Blackberries ~ Monitoring Location 2.00 FIGURE 3. IDENTIFICATION OF ENHANCEMENT AREA AND PLANTING PLAN Applied Environmental Services, Inc. 9 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan When complete, a three to one enhancement of buffer area will be achieved. Biological support will increase from the removal of invasive blackberry shrubs, and the installation of native vegetation that promotes habitat diversity. 10. CONSTRUCTION & PROJECT SCHEDULE It is the goal of the project proponent to begin invasive species removal and installation of bird houses and bat boxes when the SPAAD is approved, when financial resources become available, time is available and the weather permits. Most of the enhancement features (including the majority of the planting) will be complete before submittal of a building permit. Planting of some of the fruit trees in the vicinity of the house will occur after the home is completed to prevent accidental tree damage by construction. In June of 2002, the Department of Ecology revised its regulations on the spraying of herbicide in wetland and buffer areas. AES biologists have been using herbicide in a number of mitigation sites since that law change occurred. Next spring (2003) the patches of Himalayan blackberry will begin to be sprayed with herbicide to prevent the expansion (hopefully reduction) of the patches. As the blackberry patches are reduced in size and density, cuttings of onsite willows, salmonberry will occur. Various other native plant species from cuttings onsite may also be used to supplement the area. These will be counted toward the success of the buffer enhancement plan. Physical blackberry removal will begin following the purchase of a tractor mower. This item is not in the budget for several years. Once the blackberries are physically removed, plantings of cedar, spruce and roses will occur. Fruit trees and berries will be planted after the home is occupied. 11. GENERAL PLANTING INFORMATION Care should also be taken to assure the nurseries are providing the plant material themselves, so it is known to not have come out of a different region (Ecology 1993). It is also important to verify nurseries are cultivating their plant material rater than collecting whole plants from functioning wetlands. All plant material should be obtained from seed stock collected from the local Eco-Region to help minimize plant mortalities, ensure adaptability, decrease maintenance costs, and preserve local diversity. Depending on time of year and plant availability, containerized, bare-root, or balled and buflapped-planting material may be used for establishing shrubs and trees within the mitigation area. Using containerized plants during the growing season will optimize plant survivability due to ease of transportation and presence of a well-developed and intact root system. Many tree and shrub species are available as bare-root materials during the dormant season (October - March). Bare-root material is generally much cheaper than containerized or balled and burlapped-planting material (Ecology 1993). Buffer areas are best planted when there is adequate moisture to ensure plant survival. Bare-root material should be planted during the dormant season, while the more Applied Environmental Services, Inc. 10 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan expensive containerized plants can be planted all year (Ecology 1993). Most buffer restoration projects are scheduled for the early spring or late fall when plants are just beginning or ending their yearly growth and require less maintenance over the dry summer months (Ecology 1993). 12. MAINTENANCE Maintenance of the planted enhancement area will occur for a minimum of three years and is the responsibility of the project proponent. It is not anticipated that the planting of purchased plant material (cedar and spruce) will occur for at least one or two years following approval of the SPAAD. Following installation of purchased material, the maintenance portion of this enhancement plan will begin. First year maintenance will include periodic watering and invasive vegetation control. Maintenance during the second and third years will focus on weeding (invasive plant removal). Watering during the plant establishment period (possibly into the second summer) is crucial for plant survival and will primarily occur during the dry summer months (June through September). Watering should be done with sufficient quantities of water (up to 2-3 gallons per plant). Extremely warm weeks may necessitate watering more frequently. The watering regime should follow an irregular schedule to encourage the development of deep root systems that will reduce the need for any watering. Control of undesirable species will be maintained by periodic weeding of the mitigation area. Species to be removed primarily include exotic invasive species such as reed canary grass (Phalaris arundinacea), Himalayan blackberry (Rubus armeniacus), Evergreen blackberry (Rubus laciniatus) and Scotch broom (Cytisus scoparius). Only desirable native volunteer species in addition to those planned for the area will be encouraged to grow. Some of the other responsibilities such as trash removal, vandalism repair, etc. will be performed on an as needed basis. 13. MONITORING PROGRAM A specific set of performance standards corresponding to the stated mitigation goals has been established. These standards will be used to judge the success of this project. Baseline cover values shall be established immediately after planting. Monitoring will take place for a minimum of three years. A monitoring report will be completed at the end of each monitoring fall event. The annual monitoring reports will be sent to Jefferson County for their files. Three permanent monitoring stations, approximately eleven feet in diameter, will be installed within the project area. These monitoring stations will be identified be green, steel posts with the monitoring station number marked on the each post. Monitoring station one will be located near the chicken coop. Station two will be located on the slope southwest of the cherry tree, and the third will be in the large enhancement area within the floodplain.. Photographs will be taken from the same direction and height Applied Environmental Services, Inc. 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan prior to planting, immediately following planting, and each subsequent monitoring event. Compass direction and monitoring station will be noted for each photograph. The success of the enhancement plan is dependent upon the components specified in this plan. Baseline cover values shall be established immediately after planting. The percentage of ground covered by vegetation (planted & volunteer) will be estimated within the mitigation area. Undesirable vegetation will be identified, counted, and removed. The desirable "volunteer" plants growing in the area will also be counted, and their percent aerial coverage will be estimated. The following are the standards that must be met for project success: Invasive, exotic, and undesirable species shall be represented by less than twenty percent (20%) coverage in the buffer area after the three year monitoring period as determined by observations made within the monitoring areas. bo A minimum of eighty percent (80%) survival of all planted materials throughout the monitoring period. Survival of the enhancement planting will be determined by counting dead and live plants within the enhanced area. Each species counted will be recorded (i.e. plant name, etc.) as well as the size and general condition of each plant (i.e. growth, condition, etc.). Wildlife observations are to be made as general notes (species occurrence, nests, burrows, etc.) by the monitoring biologist at the time of the monitoring. The results will be recorded (including date & time) and reported following each monitoring event. Additional maintenance requirements (i.e. trash removal, vandalism repair, etc.) will also be documented. These observations and photographs will be compiled into a short annual report and submitted to Jefferson County. 14. CONTINGENCY PLAN If the project fails to meet the previously discussed performance standards, Jefferson County will require implementation of a contingency plan. The contingency plan can include replanting the area and may include additional maintenance and monitoring. The proposed buffer enhancement plan can fail if certain unfavorable factors occur. Disease is a factor that may occur to the newly planted vegetation. Other factors that may have a negative effect on newly planted buffer vegetation include fire, erosion, and most notably grazing by elk. If more than 20% of the plantings do not survive within any of the monitoring years, the problem areas will be replanted or supplemented with additional plants. Replanting is preferable in the dormant season and will be provided with better maintenance for higher plant survival. If alternative species are needed to improve survival percentages, the selection of alternative plant species will be made by the monitoring biologist. Applied Environmental Services, Inc. 12 22 Acre Parcel off the Duckabush Road, Wetland Buffer Enhancement Plan The success of the buffer enhancement plan is dependent upon the enhanced area meeting the established performance standards. A review of the data collected from monitoring events and the photographic record shall be conducted to determine whether activating the contingency plan is necessary. If the establishment of desirable volunteer species in the enhanced buffer area meets or exceeds the performance standards, then implementing the contingency plan would not be required, provided that Jefferson County concurs. The decision whether to waive the option to implement a contingency plan shall be made based upon the coverage of desirable volunteer species and without factoring in the survival rate of the planted vegetation. The applicant will be responsible for all costs associated with replanting, additional plant maintenance as a result of the replanting, and for all costs associated with activating the contingency plan. Applied Environmental Services, Inc. 13 REFERENCES Alternative Designs, 2002, Letter on Soil Suitability to Ms. Lisa Berntsen on the 22 Acre Parcel off the Duckabush Road Applied Environmental Services, Inc. 2002.22 Acre Parcel off the Duckabush Road, Wetland Delineation Report. Pojar, Jim and Andy MacKinnon, et al. 1994. Plants of the Pacific Northwest Coast Washington, Oregon, British Columbia and Alaska. Lone Pine Publishing, Canada. Thurston County Conservation District. Undated. A Guide to Stream Corridor Revegetation in Western Washington. Thurston County. Washington State Department of Ecology. 1993. Restoring Wetlands in Washington: A Guidebook for Wetland Restoration, Planning and Implementation. Publication No. 93-17, Olympia, Washington. I