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CriticalAreaStudy_MitigationPlan.pdfCRITICAL AREAS STUDY AND MITIGATION PLAN FOR Wetland Resources, Inc. Project # 15101 Prepared By: Wetland Resources, Inc. 9505 19th Ave SE, Suite 106 Everett, WA 98208 (425) 337-3174 For: Kent Dietz 8006 S. Lake Stevens Road Lake Stevens, WA 98258 August 10, 2015 TABLE OF CONTENTS PROPERTY LOCATION AND SITE DESCRIPTION PROJECT DESCRIPTION REVIEW OF EXISTING INFORMATION METHODOLOGY v(—gq'qL Criteria Soils Criteria 1m BOUNDARY DETERMINATION FINDINGS/RESULTS Shell Creek UPLAND/ STEEP SLOPE AREAS FUNCTIONAL ASSESSMENT PROPOSED DEVELOPMENT ACTIVITIES VARIANCE CRITERIA MITIGATION SEQUENCING BUFFER MITIGATION PLAN AND IMPACT ASSESSMENT GOALS, MONITORING, MAINTENANCE, AND CONTINGENCY (-)a Standards !jyj Planting Notes Maintenance COST ESTIMATE AND FINANCIAL GUARANTEE USE OF THIS REPORT REFERENCES APPENDICES APPENDIX A: SITE PHOTOS APPENDix B: EXISTING CONDITIONS MAP APPENDIX C: SITE PLAN AND MITIGATION MAP APPENDLx D: ENHANCEMENT AREAS PLANT LIST 2 2 2 2 3 3 4 4 5 5 8 9 12 12 13 16 16 16 16 17 18 PROPERTY LOCATION AND SITE DESCRIPTION Wetland Resources, Inc. (WRI) performed a site investigation on May 18, 2015 to delineate jurisdictional wetlands and streams on and in proximity to Snohomish County parcel number 00434208401000. The subject property is located at 742 Daley Street in the City of Edmonds, Washington. The Public Land Survey System (PLSS) locator for the subject property is Section 24, Township 27N, Range 03E, W.M. The study site is situated within the Cedar/Sammamish Watershed, Water Resources Inventory Area (WRIA) 8. The 0.24 -acre subject property is situated in an urban/residential setting approximately one-half mile northeast of downtown Edmonds. It is an undeveloped parcel that contains dense forest and scrub -shrub vegetation. Species observed during the site inspection include, but are not limited to, big leaf maple (Acer macrophyllum), western red cedar (Thuja plicata), red alder (Alnus rubra), Doug fir (Pseudotsuga menziesii), vine maple (Acer circinatum), beaked hazelnut (Corylus cornuta), thimbleberry (Rubus pa7vyi1orw), salmonberry (Rubus spectabilis), lady fern (Athyrium fzlix femina), sword fern (Polystichum munitum), and giant horsetail (Equisetum telmateia). Several invasive/non- native species are also present, including Himalayan blackberry (Rubes armeniacus), English ivy (Heder°a helix), and Japanese yellow rose (Kerriayjxaponica). The subject property is bordered on the east, west, and south by developed parcels/single-family homes and on the north by Daley Street. The topography of the site is characterized by steep slopes on the western portion of the site and a relatively flat area in the northeast portion. PROJECT DESCRIPTION One stream (Shell Creek) and a landslide hazard area were identified during the May 18 site investigation. Shell Creek is a fish -bearing stream that contains anadromous species. As such, it requires a 100 -foot protective buffer per section 23.90.040(D)(1) of the Edmonds Community Development Code (ECDC). The property owner/project applicant is proposing to construct a single-family home and driveway on the subject property. The subject property is completely encumbered by the Shell Creek buffer, making it impossible to avoid buffer impacts and meet the standard mitigation requirements. Therefore, the applicant is requesting a variance from the standard requirements contained in Title 23 of the ECDC in order to complete the project. Mitigation for unavoidable buffer impacts will be provided. REVIEW OF EXISTING INFORMATION Prior to conducting the site investigation, public resource information was reviewed to gather information on the subject property and the surrounding area in regards to wetlands, streams, and other critical areas. The following information was examined: • l.lnatccl t. tt:. Fr a„ and Wildlilje.Service (Ll` a) Nqtiopal Wetlapds lnventoryw The National Wetland Inventory (NWI) does not illustrate any wetland areas on or near the subject property. • USDA/Natut°a1 lit so ul c t s `onsc rvat on c z vrt � _(NR C S Web Soil Spivey: The Web Soil Survey indicates that the subject property is underlain by Alderwood-Urban land complex, 8 to 15 percent slopes. Although this soil is not considered hydric per the NRCS, it does contain small hydric soil inclusions. • a l __.'')a.�arrtaS;aa�,: laatcrc:':. WdLsl�a1a Ston lac ���rCtnc nt.... of Fish and W interactive map i� . 9 Mapping� kt in: The SalmonScape illustrates Shell Creek flowing Wetland Resources, Inc. 1 Dietz — Daley Street August 10, 2015 WRI Project #15101 through the subject property. SalmonScape indicates that Coho salmon utilize Shell Creek. WDFW Priod R-lA talr d m ap trca ('11 tatm «�c t�va 1"�P at):, The PHS Interactive Map illustrates Shell Creek flowing through the subject property. The PHS data indicates that both Coho salmon and resident coastal cutthroat utilize Shell Creek. Stiolior' ish Cgunt Intc °,activ 311 .: The SnoScape Interactive Map shows Shell Creek on the subject property and indicates that it is a Type F stream. The SnoScape Map also illustrates steep slopes (i.e. >33%) on the western portion of the subject property. METHODOLOGY Wetland boundaries were determined using the routine determination approach described in the Corns of Engineers Wetlands Delineation Manual (Environmental Laboratory 1987) and the ftj,qn,tl c;l�et.(,,or .. �c�of 4 1c<nrs xeet'�0).Wetland I�I��e�tioranua :_. 2 t k �c w— �r rttia � V l _s... (l Coast t (U.S. Army Corps of Engineers 01 ). Under the routine methodology, the process for making a wetland determination is based on three steps: 1.) Examination of the site for hydrophytic vegetation (species present and percent cover); 2.) Examination of the site for hydric soils; 3.) Determining the presence of wetland hydrology The following criteria must be met in order to make a positive wetland determination: )V' , !tiq!R Criteria: The Corps Manual and 2010 Regional Supplement define hydrophytic vegetation as "the assemblage of macrophytes that occurs in areas where inundation or soil saturation is either permanent or of sufficient frequency and duration to influence plant occurrence." Field indicators are used to determine whether the hydrophytic vegetation criteria have been met. Examples of these indicators include, but are not limited to, the rapid test for hydrophytic vegetation, a dominance test result of greater than 50%, and/or a prevalence index score less than or equal to 3.0. Soils Criteria The 2010 Regional Supplement (per the National Technical Committee for Hydric Soils) defines hydric soils as soils "that formed under conditions of saturation, flooding or ponding long enough during the growing season to develop anaerobic conditions in the upper part." Field indicators are used to determine whether a given soil meets the definition for hydric soils. Indicators are numerous and include, but are not limited to, presence of a histosol or histic epipedon, a sandy gleyed matrix, depleted matrix, and redoximorphic depressions. d piggy -.(riters Wetland hydrology encompasses all hydrologic characteristics of areas that are periodically inundated or have soils saturated to the surface for a sufficient duration during the growing season. Areas with evident characteristics of wetland hydrology are those where the presence of Wetland Resources, Inc. 2 Dietz — Daley Street August 10, 2015 WRI Project # 15101 water has an overriding influence on the characteristics of vegetation and soils due to anaerobic and chemically reducing conditions, respectively. The strongest indicators include the presence of surface water, a high water table, and/or soil saturation within at least 12 inches of the soil surface. BOUNDARY DETERMINATION FINDINGS/RESULTS One stream — Shell Creek — was identified on the subject property during the May 18 site investigation. No wetlands were observed. The ordinary high water mark (OHWM) of the stream was identified using the methodology described in the Washington State Department of (Olson and dale 2010 tThe strea t� s classified according to Ecology document Dcte�m���_„”pil -.rearns n �ta1� St^c°ol��cl Review lea ��tt, m was to the water typing criteria contained in the Washington Administrative Code (WAC), section 222- 16-030. This is consistent with ECDC section 23.90.010. The stream was further classified using the U.S. Fish and Wildlife Service (USFWS) document Classifications of Wetlands and 1 United States (Cowardin et al., 1979), also known as the Cowardin °�a�i � Hahttats of the „µ_ _ Classification System. Shell Creek Shell Creek originates slightly over one mile southeast of the subject property, just outside the border of Yost Park. It flows in a northwesterly direction until it reaches Aloha Street, at which point it turns slightly and flows almost directly north to Puget Sound. Shell Creek bisects the northeastern corner of the subject property, flowing through a heavily shaded stream channel that is armored on both banks with rip -rap (the northernmost, on-site portion of the stream is not armored, however). The adjacent, off-site portion of the channel (to the southeast) is also armored, yet shading is minimal. At the north end of the subject property, Shell Creek flows through a large box culvert and continues off-site to the northeast. A fish ladder is located within the box culvert. The stream substrate is comprised primarily of cobble, gravel, and small boulders, but sand and silt are also present. The stream channel is approximately 8 to 10 feet wide and approximately two feet deep. The depth of water during the May 18 site investigation ranged from 4 inches to approximately 11 inches. Several small riffle areas were observed within the stream, as well as one or two small drops. The adjacent streamside/buffer vegetation is comprised of native trees, shrubs, and herbaceous species, though some non-native/invasive vegetation is present as well (e.g. English ivy). The dominant plant species immediately adjacent to the stream include western red cedar, red alder, vine maple, salmonberry, sword fern, and giant horsetail. The remainder of the stream buffer (which comprises the entire property) also contains these species, as well as big leaf maple, Doug fir, cherry (Prunus sp.), beaked hazelnut, thimbleberry, lady fern, Himalayan blackberry, and Japanese yellow rose. The Japanese yellow rose shrubs are primarily concentrated in the southern/ southeastern portion of the property. Shell Creek meets the criteria for a Type F stream per WAC 222-16-030. It contains anadromous species and, as such, requires a 100 -foot buffer (ECDC 23.90.040(D)(1)). Under the Cowardin classification system, Shell Creek is a Riverine — upper perennial — unconsolidated bottom — cobble/gravel system (R3UB1). In addition, Shell Creek meets the criteria for a Fish and Wildlife Habitat Conservation Area (FWHCA) per ECDC 23.90.010. Type F streams as Wetland Resources, Inc. 3 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 well as areas associated with state priority species are considered FWHCA's. Coho salmon and resident coastal cutthroat are priority species per WDFW. UPLAND/ STEEP SLOPE AREAS The western portion of the subject property is comprised of dense forested vegetation and steep slope areas. The steep slopes constitute a landslide hazard area, which are regulated under chapter 23.80 of the ECDC. Previous geotechnical evaluations of the subject property (as well as the current study) have deemed the on-site landslide hazard areas safe for development/construction. One data point was recorded on the steep slope on the western portion of the subject property. Soils in that vicinity consisted of black (IOYR 2/1) sandy loam to a depth of 8 inches and dark brown (10YR 3/3) sandy loam between 8 and 20 inches in depth. These characteristics are indicative of non -hydric soils. Indicators of wetland hydrology were not observed in this area. The vegetation at this data point is dominated by big -leaf maple, western red cedar, red alder, thimbleberry, Himalayan blackberry, sword fern, and herb Robert (Geranium robertianum). The vegetation is indicative of an upland/non-wetland area. FUNCTIONAL ASSESSMENT The methodology for this functions and values assessment is based on professional opinion developed through past field analyses and interpretations. This assessment pertains specifically to the on-site stream system, but is typical for assessments of similar systems throughout western Washington. Streams and their associated buffers in western Washington perform a variety of ecosystem functions including the movement of water and sediment, flood flow alteration, recharge of groundwater, treatment of pollutants, dynamic stability, and habitat diversity. The functional assessment for Shell Creek and its buffer is provided below. The on-site stream serves to collect stormwater from the surrounding areas and convey it to downstream systems. The dense forest and scrub -shrub vegetation aids in flood flow alteration by slowing the velocity of overland flow/runoff. However, this function is hampered by the steep topography of the site and the armored stream channel (lack of overbank flooding). The presence and condition of the buffer vegetation also aids in erosion control and, to a limited extent, with sediment removal. Plant species richness is provided by the stream buffer; the majority of the buffer is comprised of dense native vegetation with scattered areas of invasive/non-native species. Habitat for birds and small mammals is also provided by the buffer. Shell Creek provides limited to moderate fish habitat. The stream channel is well shaded, which aids in temperature regulation, and it provides a direct connection to Puget Sound. However, in - stream habit (e.g. large woody debris, backwater channels, riffles and pools, etc.) is somewhat limited. Despite the setbacks, Shell Creek is still utilized by anadromous species. Along with the preceding functions and values, stream buffers often provide additional functions in western Washington such as physical protection of the stream and aesthetic value. Wetland Resources, Inc. 4 Dietz — Daley Street August 10, 2015 WRI Project # 15101 PROPOSED DEVELOPMENT ACTIVITIES The applicant is proposing to construct a single-family home and driveway on the subject property. The house will be located approximately 33 feet south of the north property line and 45 feet north of the southern property line. The northwestern corner of the house will be setback five feet from the western property line (the structure will be constructed at an angle to the western property line; the southwestern corner will sit 15.5 feet from the property line). The driveway will measure approximately 33 feet long and approximately 14.75 feet in width at its widest point, for a total area of 421 square feet (SF). Two gabion walls will also be constructed, one on each side of the driveway, and will match the existing slopes. The walls total 48 SF in area. The house will measure 36 feet by 18 feet for a total area of 648 SF. In addition to these structures, a footbridge will be constructed on the east side of the driveway and will extend eastward to the top of the box culvert. The previous property owners had constructed a gazebo/trellis structure on top of the box culvert. This structure has since been removed. The top of the box culvert is flat and is meant to be utilized by the owner of the property per the City of Edmonds Architecture Design Board Q. McConnell, personal communication, May 19, 2014). Since the subject property is completely encumbered by critical areas and critical area buffers, permanent impacts are unavoidable. The Shell Creek buffer covers the entire subject property and the landslide hazard area covers almost the entire western portion of the subject property. These encumbrances leave absolutely no room for development that doesn't result in critical area or buffer impacts. Therefore, in order to complete the project, the applicant is requesting a variance from the standard critical area regulations contained in Title 23 of the ECDC. VARIANCE CRITERIA Section 23.40.210(A)(2) of the ECDC lists the specific variance criteria for development proposals not involving a public agency or public utility. A variance from the standards of Title 23 may be authorized only if a project applicant demonstrates that the application of the title would deny all reasonable economic use of a subject property. "Reasonable Economic Use" is defined in ECDC 23.40.320 as "the minimum use to which a property owner is entitled under applicable state and fe(Iffal constitutional provisions in order to avoid a taking and/or violation of substantiae due process." Section 23.40.210(A)(2) of the ECDC states that the applicant must demonstrate the following (project - specific responses follow each item: a) The application of this title would deny all reasonable economic use of a property or subject parcel Enforcing the critical areas regulations contained in Title 23 of the ECDC would result in a parcel that is completely encumbered by critical areas and critical area buffers. Utilizing the stream buffer width reduction allowance described in ECDC 23.90.040(D)(2) still would not allow for enough room for development of the site without impacting a portion of the Shell Creek buffer and landslide hazard area. In addition, the stream buffer width averaging allowance described in ECDC 23.90.040(D)(3) is not applicable to this project since there is no room on the subject property to replace averaged buffer areas. Complete avoidance of critical area and/or buffer impacts is not possible unless all reasonable uses of the subject property are completely denied. Not allowing development of the property would result in an economic hardship for the project applicant. Wetland Resources, Inc. 5 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 b. No other reasonable economic use of the property consistent with the underlying zoning and the city comprehensive plan has less impact on the critical area Due to its size, location, and setting, the options for reasonable economic use of the subject property are limited. The property is zoned Single -Family Residential (RS -6) and is surrounded by developed lots and single-family homes. It is located in a residential/urban community. Per section 16.20.0 10 of the ECDC, permitted primary uses within the RS zone include single-family dwelling units, churches, primary schools, local public facilities that are planned, designated, and sited in the capital improvement plan, and neighborhood parks, natural open spaces, and community parks with an adopted master plan. The construction of a church or primary school on the subject property is clearly not feasible and is not consistent with the applicant's goals for the property. Public facilities, neighborhood parks, and natural open spaces are also not feasible since the property is privately owned. Permitted secondary uses within the RS zone include the following: foster homes; home occupation; renting of rooms without separate kitchens; accessory buildings (fallout shelters, private greenhouses covering no more than five percent of the site, private stables, private parking for up to five cars, and private swimming pools/recreational facilities); private residential docks or piers; family day-care; commuter parking lots; bed and breakfasts. These uses are not feasible for the subject property due to its extremely small size and current undeveloped state. With the exception of a small, single-family home, there are no other practical, reasonable uses for the subject property. c. The proposed impact to the critical area is the minimum necessary to allow for reasonable economic use of the property The proposed single-family residence has been designed to have a very small footprint (648 SF) while still providing a comfortable living space. The proposed home is much smaller than the surrounding single-family residences. It will not contain a garage, deck, or any other basic amenities. Only the home, driveway, gabion walls, and footbridge will be constructed on the subject property. The proposed location of the home is the most reasonable. It is located as far from the stream as possible without the need for a long driveway. Placing the home in the southwest corner of the subject property would provide more room and buffer between it and Shell Creek, yet it would require a much longer driveway, thereby resulting in even greater stream buffer impacts than the current plan. d. The inabiliy of the applicant to derive reasonable economic use of the propery is not the result of actions by the applicant after the effective date of the ordinance codified in this title or its predecessor The applicant has not performed any actions or activities that that have resulted in the current state of the subject property. Shell Creek, the Shell Creek buffer, and the landslide hazard area are all pre-existing features that are well known by both the City of Edmonds and the project applicant. e. The proposal does not pose an unreasonable threat to the public healthy safey, or welfare on or off the development proposal site; The proposed development project will have no impact on the public health, safety, or welfare, Wetland Resources, Inc. 6 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 either on or off the subject property. The proposed single-family home and associated driveway are small and do not encroach onto any neighboring parcels or public areas. The proposed project is in accord with the surrounding neighborhood and is smaller than the surrounding single-family homes. This is a private property and a private development proposal; it will not involve the public or impact them in any way. f. The proposal minimizes net loss of critical area functions and values consistent with the best available science The proposed development project has been designed to have a minimum amount of impacts while still meeting the needs of the applicant. Outside of the building and driveway footprints, the stream buffer will remain intact. The stream itself will not be altered in any way by the proposed project. The landslide hazard area has been deemed safe for development by a licensed geotechnical engineer. A buffer mitigation plan has been developed that will compensate for the stream buffer impacts. This mitigation plan was developed in accordance with Best Available Science and utilized guidance documents prepared by the Washington State Department of Ecology (Ecology). It is meant to maintain the functions and values of the stream buffer. Furthermore, the methods used to assess the stream and its buffer are consistent with the methods and practices employed by professional ecologists. g. The proposal is consistent with other applicable regulations and standards. The proposed project will be in conformance with all applicable City of Edmonds regulations. Specific variance criteria are listed in section 23.40.210(B) of the ECDC. This section of the ECDC states that the applicant must demonstrate that the proposed project conforms to the following criteria (project -specific responses follow each item): 1. Special conditions and circumstances exist that are peculiar to the land, the lot, or something inherent in the land and that are not applicable to other lands in the same district Special conditions on the subject property include a fish -bearing stream, a 100 -foot stream buffer, and a landslide hazard area. These features encumber the entire site. While a few of the other parcels in the vicinity contain streams and/or landslide hazard areas, they were developed prior to the adoption of the City of Edmonds' current critical areas regulations and, therefore, were not required to maintain any protective buffers. 2. The special conditions and circumstances do not result from the actions of the applicant The presence of critical areas and buffers on the subject property are not the result of any actions by the project applicant. These features have always been present. 3. A literal interpretation of the provisions of this title would deprive the applicant of all reasonable economic uses and privileges permitted to other properties in the vicinity and zone of the subject property under the terms of this title, and the variance requested is the minimum necessary to provide the applicant with such rights. Fully enforcing the regulations contained in Title 23 would result in a parcel that is completely encumbered by critical areas and critical area buffers. Utilizing the stream buffer width reduction allowance described in ECDC 23.90.040(D)(2) still would not allow for enough room for development of the site without impacting a portion of the Shell Creek buffer and landslide Wetland Resources, Inc. 7 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 hazard area. In addition, the stream buffer width averaging allowance described in ECDC 23.90.040(D)(3) is not applicable to this project since there is no room on the subject property to replace averaged buffer areas. Not allowing development of the property would result in an economic hardship for the project applicant. All of the surrounding lots in the immediate vicinity are developed. The variance being requested is the minimum necessary to provide the applicant with a reasonable economic use of the property. As previously stated, there are no other practical, reasonable uses for the subject property that would be in conformance with the area's zoning regulations. 4. Granting the variance requested will not confer on the applicant any special privilege that is denied by this title to other lands, structures, or buildings under similar circumstances The requested variance would only allow the applicant to construct a single-family home on the subject property, which is consistent with surrounding land uses. It would not grant any privileges to the project applicant that aren't enjoyed by adjacent land owners. 5. The granting of the variance is consistent with the general purpose and intent of this title, and will not further lc� rade the functions or values of the associated critical areas or otherwise be materially detrimental to the public welfare or injurious to the property or improvements in the vicinity of the subject properly The proposed development project will have no negative impacts on the public welfare, nor will it be injurious to property or improvements near the subject property. The proposed single- family home and associated driveway are small and do not encroach onto any neighboring parcels or public areas. The proposed project is in accord with the surrounding neighborhood and is smaller than the surrounding single-family homes. Although the project will result in unavoidable impacts to the buffer of Shell Creek, the proposed mitigation plan will compensate for these impacts and will maintain the functions and values of the buffer. Granting the variance is consistent with the general intent of Title 23 of the ECDC. 6. The decision to grant the variance is based upon the best available science and gives special consideration to conservation or protection measures necessary to preserve or enhance anadromous fish habitat. Best available science has been used in the analysis of the on-site conditions, specifically Shell Creek and the adjacent buffer. In addition, the proposed mitigation plan was developed in accordance with Best Available Science; it utilizes guidance documents prepared by the Washington State Department of Ecology (Ecology). Both the proposed development and the mitigation plan have been designed to maintain the functions and values of the stream buffer while still meeting the project goals. Only the minimum amount of buffer necessary will be altered for the proposed development. Furthermore, the proposed structures are small compared with those located on adjacent, developed parcels. MITIGATION SEQUENCING Section 23.040.120 of the ECDC lists mitigation sequencing requirements for projects that will result in alteration of a critical area. Per the ECDC, alterations to critical areas shall be avoided, minimized, or compensated for in the following sequential order of preference (project specific responses follow each item): Wetland Resources, Inc. 8 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 1) Avoiding the impact altogether by not taking a certain action or parts of an action. Due to the encumbrances on the subject property, complete impact avoidance cannot be achieved. Shell Creek and its buffer encompass the entire subject property, making it impossible to utilize the site without impacting one or both of these areas. 2) Minimizing impacts by limiting the de4ree or magnitude of the action and its implementation by using appropriate technology or by taking affirmative steps, such as project redes ;in, relocation, or timing to avoid or reduce impacts. The proposed development has been designed to minimize critical area impacts to the greatest extent practicable. The proposed house and driveway are very small (1,069 SF combined), much smaller than those found on neighboring parcels. The structures will be located on the subject property in such a way as to minimize the overall buffer impacts. 3) Rect�ioing the impact to wetlands, frequently flooded areas, and fish and tildlir habitat conservation areas by repairing rehabilitating or restoring the affected environment to the historical conditions or the conditions existing at the time of the initiation of the project. The affected area/environment cannot be restored to historical or pre-existing conditions since the impacts will be permanent in nature. The proposed house and driveway will be permanent fixtures on the subject property. 4) Minimizing or eliminating the hazard by restoring or stabilizing the hazard area through engineering or other methods. The landslide hazard area has been deemed safe for development by a licensed geotechnical engineer. Standard erosion control best management practices (BMP's) will be employed to avoid and minimize impacts to the on-site steep slopes. 5) Reducing or eliminating the impact or hazard over time by preservation and maintenance operations during the life of the action. Due to the permanent nature of the impacts, they cannot be reduced or eliminated over time. The remainder of the property and stream buffer, however, will be maintained in its current condition. 6) Compensating for the impact to wetlands, frequently flooded areas, and fish and wildlife habitat conservation areas by replacing enhancing or providing substitute resources or environments. A buffer mitigation plan has been developed to compensate for the unavoidable impacts. The mitigation plan is discussed below. 7) Monitoring the hazard or other required mitigation and taking remedial action when necessary. Monitoring, maintenance, and contingency plans have been developed concurrently with the mitigation plan. BUFFER MITIGATION PLAN AND IMPACT ASSESSMENT The proposed development project will result in unavoidable buffer impacts. These include the single-family home, driveway, gabion walls, footbridge, and all of the area within the boundary of the proposed split -rail fence. To compensate for these impacts, buffer enhancement will be performed. Approximately 1,617 SF of stream buffer will be enhanced with native trees and Wetland Resources, Inc. 9 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 shrubs. In addition, a split -rail fence will be installed between the new single-family home and the stream buffer in order to prevent intrusion into and disturbance of the buffer. Section 23.40.280 of the ECDC states that buildings and other structures must maintain a 15 -foot setback (BSBL) from the edges of all critical areas and buffers; however, a 10 -foot BSBL from the proposed house is being proposed for this project. A larger BSBL would result in the removal of more stream buffer than a smaller setback. The small setback still allows for an open area, or "break," between the proposed house and buffer while keeping more of the buffer intact and unaltered. Per ECDC section 23.40.110(B), mitigation shall be in-kind and on-site, when possible. Since the buffer impacts are occurring on the project site, on-site mitigation makes the most sense. Furthermore, the project site (and the City of Edmonds) is not located within the service area of an approved mitigation bank, and the City of Edmonds does not have an in -lieu fee mitigation option, so on-site mitigation is the only viable option. Although a portion of the on-site stream buffer will be permanently impacted by the proposed project, the proposed mitigation plan and preservation of the remaining stream buffer are expected to maintain stream and buffer functions. The entirety of the subject property outside of the development area/split-rail fence will remain untouched and vegetation will be preserved. The split -rail fence will prevent further intrusion into the buffer by demarcating a clear boundary. While some vegetation will need to be removed in order to construct the proposed project, the proposed buffer enhancement areas will be planted with native trees and shrubs to offset this loss. The remaining buffer vegetation and new trees and shrubs will continue to provide limited flood -flow alteration and erosion control. Plant species richness will be maintained due to the preservation of the remaining stream buffer vegetation and the installation of new vegetation. The proposed project will not impact Shell Creek, so the stream functions shall be preserved. Furthermore, stream shading will remain relatively intact since clearing immediately adjacent to the stream will not occur. Five buffer enhancement areas will be established on the subject property. Three of these areas will receive native trees and shrubs. The remaining two enhancement areas, which will be located along the northern portion of the stream channel, will be planted with willow stakes. These stream bank enhancement areas are not armored and are capable of being planted. The willow stakes are fast growing species and will provide shade for the northern portion of the stream. Prior to planting, invasive/non-native species shall be removed from all enhancement areas. Tables 1 through 5 list the species that will be planted within the buffer enhancement areas. Wetland Resources, Inc. 10 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 Table 1: Species List for Enhancement Area #1 (984 SF) Species Scientific Name Size Spacing Quantity Douglas fir* P1.seudotsu�a menziesii 1 gallon 8' on -center (OC) 7 Vine maple Acer circinatum 1 gallon TOC 20 Thimbleberry Rubus ¢arviflorus 1 gallon TOC 20 Snowberry Symphoricar¢os albus 1 gallon 3' OC 20 Cascara Fran -Ma hurshiana 1 gallon 3' OC 20 Sword fern Polystichum munitum 1 gallon TOC 20 *Doug fir shall only be planted in the northern, open portion of Enhancement Area #1. Quantity decreased to account for smaller planting area. Table 2: Species List for Enhancement Area #2 (212 SF) Table 3: Species List for Enhancement Area #3 (228 SF) Species Scientific Name Size Spacing Quantity Douglas fir PseudotszW menziesii 1 gallon 8' OC 2 Western red Thuja plicata 1 gallon 8' OC 2 cedar Vine maple Acer circinatum 1 allon TOC 4 ' Thimbleberry Rubus ¢aTiflorus 1 gallon TOC 4 Snowberry Synhhoricarms albus 1 gallon TOC 4 Cascara Fran,uula ¢urshiana 1 vallon TOC 4 Sword fern Polystichum munitum 1 gallon TOC 5 Table 4: Species List for Enhancement Area #4 (77 SF) Table 5: Species List for Enhancement Area #5 (116 SF) Planting Area #3 is currently dominated by a non-native flowering shrub (Japanese yellow rose; Kem'a_7aponica). These plants will be removed from the planting area prior to installation of the native vegetation. Wetland Resources, Inc. 1 1 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 The exact location and configuration of the planting areas may need to be adjusted slightly due to existing vegetation. This will be done on-site by the lead ecologist and landscaper (or project applicant if he chooses to install the vegetation) prior to planting. Any changes to the planting areas will be discussed in the as -built report (described below). If possible, plant installation should take place in late fall or early spring (prior to the start of the growing season). Plants shall be obtained from a reputable nursery familiar with native vegetation and that is capable of providing local genetic stock. Limited species substitution may be allowed; however, the City of Edmonds and/or the lead ecologist must approve the substitution. A mulch containing wood chips and some green/vegetative material shall be applied in a 3 -foot radius around the base of each installed plant to a depth of 2-4 inches. Mulch will provide nutrients to the new trees and shrubs and will help suppress establishment of weedy species. In order to avoid stem decomposition/rot, the mulch shall not be allowed to touch the plant trunks/ stems. Plants shall be arranged with the appropriate numbers, sizes, species, and distribution to achieve the required vegetation coverage. The actual placement of individual plants shall mimic natural, asymmetric vegetation patterns found on similar undisturbed sites in the area. Lath staking, brightly colored flagging, or another form of marking shall be placed on or near each installed plant to assist in locating the plants during maintenance and monitoring activities. Irrigation shall be provided during the first two years of the monitoring period and will occur during the summer/dry season (e.g. June through September), any extensive dry periods, and/or as determined by the lead ecologist. Water shall be applied to the new plants at a rate of one (1) inch per week. Irrigation can be provided via hand watering or through a temporary irrigation system. The lead ecologist shall be on-site to inspect plant materials for proper size and quality, inspect the layout and planting locations, and to complete a final walk-through before approving the buffer enhancement actions. GOALS, MONITORING, MAINTENANCE, AND CONTINGENCY Gaal , j,+ +e_ay gtLndd, Performance Standards Project goals are established to identify what the mitigation plan is attempting to accomplish. Objectives identify specific actions that are taken or components that are initiated in order to meet the project goals. Finally, performance standards provide measurable criteria for determining if the goals and objectives are being achieved (Washington State Department of Ecology et. al., 2006). The goals of this mitigation plan include the following: Compensate for the loss of stream buffer resulting from the development. • Provide protection for the on-site stream buffer. Wetland Resources, Inc. 12 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 These goals will be met by performing the following actions (i.e. objectives): Enhance 1,617 SF of existing stream buffer by installing 14 native trees, 80 native shrubs, 29 native ferns, and 24 willow stakes within the enhancement areas. • Install a permanent, split -rail fence along the edge of the on-site stream buffer. The performance standards for the buffer enhancement areas include the following: • Survival of planted trees, shrubs, ferns, and willow stakes will be 100% following the first year of monitoring; 80% following the third year; and 70% by the fifth year. All dead plants shall be replaced following the first year of monitoring. • Tree and shrub areal coverage will be 30% at the end of the third year of monitoring and 60% at the end of the fifth year of monitoring (Note: desirable native volunteer species (e.g. red alder, salmonberry) may contribute up to 20% cover in each enhancement area. If volunteer species exceed 20% cover, control measures shall be initiated in an effort to maintain species diversity). • Invasive and non-native species shall not provide more than 25% areal coverage throughout the enhancement areas at any time. • The split -rail fence shall be installed per the specifications and shall be maintained throughout the five-year monitoring period. Planting notes Inspections The lead ecologist shall be present on site to inspect the plants prior to planting and may periodically inspect the mitigation installation process. Minor adjustments to the original design may be necessary prior to and during construction due to unusual or unknown site conditions. A City of Edmonds representative and/or the lead ecologist will make these decisions during construction. Planting If possible, plant installation will take place in late fall or early spring (prior to the start of the growing season). Plants shall be obtained from a reputable nursery familiar with native vegetation and that is capable of providing local genetic stock. Limited species substitution may be allowed, but must be approved by City of Edmonds personnel and/or the lead ecologist. Erosion and Sediment Control Measures Standard erosion and sediment control measure BMP's shall be employed during construction and during the planting process. These may include, but are not limited to, installation of silt fencing between the construction area and stream buffer; use of high -visibility fencing; spreading hay or using plastic covering on exposed ground or disturbed areas; mulching; preserving natural vegetation. Handling Plants shall be handled to avoid damage, including breaking, bruising, root damage, sunburn, drying, freezing, or other injury. Plants must be covered during transport. Plants shall not be bound with wire or rope in a manner that could damage branches. Protect plant roots with Wetland Resources, Inc. 13 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 shade and wet soil in the period between delivery and installation. Do not lift container stock by trunks, stems, or tops. Do not remove from containers until ready to plant. Water all plants as necessary to keep moisture levels appropriate to the species requirements. Plants shall not be allowed to dry out. All plants shall be watered thoroughly immediately upon installation. Soak all containerized plants thoroughly prior to installation. Storage Plants stored for longer than one month prior to planting shall be planted in nursery rows and treated in a manner suitable to specific species requirements. Plants must be re -inspected by the lead biologist prior to installation. Damaged plants Damaged, dried out, or otherwise mishandled plants will be rejected at installation inspection. All rejected plants shall be immediately removed from the site. Plant Names Plant names shall comply with those generally accepted in the native plant nursery trade. Any question regarding plant species or variety shall be referred to the lead ecologist. All plant materials shall be true to species and variety and legibly tagged. Quality and condition Plants shall be normal in pattern of growth, healthy, well branched, and vigorous, with well- developed root systems, and free of pests and diseases. Damaged, diseased, pest -infested, scraped, bruised, dried out, burned, broken, or defective plants will be rejected. Roots All plants shall be containerized with the exception of the willow stakes. Root bound plants or B&B plants with damaged, cracked, or loose root balls (major damage) will be rejected. Immediately before installation, plants with minor root damage (e.g. broken and/or twisted roots) must be root -pruned. Matted or circling roots of containerized plantings must be pruned or straightened and the sides of the root ball must be roughened. Sizes Plant sizes shall be the size indicated in Tables 1 through 5, above. Larger stock may be acceptable provided that it has not been cut back to the size specified, and that the root ball is proportionate to the size of the plant. Smaller stock may be acceptable, and preferable under some circumstances, based on site-specific conditions. Any changes to the original mitigation design must be approved by the lead ecologist and/or the City of Edmonds. Measurements, caliper, branching, and balling and burlapping shall conform to industry standards. Form Evergreen trees shall have single trunks and symmetrical, well-developed form. Deciduous trees shall be single trunked unless specified as multi -stem in the plant schedule. Shrubs shall have multiple stems and be well branched. Wetland Resources, Inc. 14 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 Weedii r Non-native and invasive vegetation in the mitigation areas will be hand weeded from around all newly installed plants at the time of installation and on a routine basis throughout the monitoring period. No chemical control of vegetation on any portion of the site is allowed without the approval of the City of Edmonds. Site conditions The contractor shall immediately notify the lead ecologist of drainage or soil conditions likely to be detrimental to the growth or survival of plants. Planting operations should not be conducted under the following conditions: freezing weather, when the ground is frozen, excessively wet weather, excessively windy weather, or in excessive heat. Planting Pits Planting pits should be circular with vertical sides, and should be at least twice the size of the root ball. In compacted soils, the sides of the planting pits should be scarified/broken up. Set plants upright in pits. Burlap, if used, shall be removed from the planting pits. Backfill shall be worked back into holes such that air pockets are removed without compacting the soils. Water Plants should be watered midway through backfilling, and again upon completion of backfilling. For late spring/early summer plantings (if approved), a rim of earth should be mounded around the base of the tree or shrub no closer than the drip line, or no less than 30" in diameter, except on steep slopes or in hollows. Plants should be watered a second time within 24-48 hours after installation. The earthen rim/dam should be leveled prior to the second growing season. Staking Due to the small size of the proposed plantings, staking should not be necessary. If the plant does need support, then strapping or webbing should be used as low as possible on the trunk to loosely brace the tree with two stakes. Do not brace the tree tightly or too high on the trunk. Do not use wire in a rubber hose for strapping as it exerts too much pressure on the bark. As soon as supporting the plant becomes unnecessary, stakes should be removed. All stakes must be removed within two (2) years of installation. Plant Location Lath staking, brightly colored flagging, or another form of marking shall be placed on or near each installed plant to assist in locating the plants during maintenance and monitoring activities. Arrangement and Spacing The plants shall be arranged with the appropriate numbers, sizes, species, and distribution to achieve the required vegetation coverage. The actual placement of individual plants shall mimic natural, asymmetric vegetation patterns found on similar undisturbed sites in the area. Mulch A wood chip mulch (containing some green/vegetative material) will be placed around the base of each plant in a 3 -foot radius and at a depth of 2 to 4 inches. Mulch shall not be allowed to contact plant stems in order to avoid plant decay and rot. Wetland Resources, Inc. 15 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 Monito�in A monitoring plan will begin with the preparation of an as -built report following completion of the mitigation plan. This report will address the completed mitigation plan and identify if any changes or revisions have been made. Following submittal of the as -built plan, monitoring visits will occur. Monitoring will begin the first year following mitigation installation. Monitoring visits will occur annually (in the late spring/early summer) for a period of five years. Due to the small sizes of the enhancement areas, monitoring techniques will include visual observations to assess tree and shrub survivability and coverage. Plant counts will also be performed within each enhancement area. Photo points shall be established within each enhancement area in order to provide photo documentation of the mitigation site. Photos will be included in each monitoring report. Monitoring reports will be submitted to the City of Edmonds in the fall of each monitoring year. The reports will summarize the overall conditions of the mitigation areas and discuss whether the performance standards are being met. On year 5, the final monitoring report will be prepared and will discuss whether or not the mitigation plan has been successful per the established goals, objectives, and performance standards. If the mitigation plan is deemed unsuccessful, contingency actions will be utilized and/or the monitoring period may be extended. If, during any of the monitoring visits, 20% of the plants within any enhancement area, or in any particular stratum within an enhancement area, are severely stressed, or it appears that 20% may not survive, additional plants will be installed. If invasive and non-native species exceed 25% aerial coverage within any of the enhancement areas at any time, control measures will be initiated. Additional contingency actions may include, but will not be limited to, more aggressive weed control, additional mulching, species substitution, soil amendments, and/or additional irrigation. If necessary, a meeting between the lead ecologist and City of Edmonds personnel will be held to develop additional contingency actions. Maintenance Maintenance will be performed within the enhancement areas annually. Maintenance actions may include, but are not limited to, replacement of dead vegetation, removal of invasive and non-native vegetation, trash cleanup, and fence repair. Maintenance needs will be discussed in the annual monitoring reports. Completed maintenance tasks and maintenance that needs to be done will be addressed in each monitoring report. COST ESTIMATE AND FINANCIAL GUARANTEE The following is a cost estimate for plant materials, labor, monitoring, and maintenance. This does not represent an actual bid (please note: plant prices include labor and installation): Plants — $9.50/plant: Estimated cost of monitoring: Estimated cost of maintenance: Total: Wetland Resources, Inc. August 10, 2015 $1,700.50 $3,200.00 $1,000.00 $5,900.50 16 Dietz — Daley Street WRI Project # 15 101 Per ECDC section 23.40.130M, a financial guarantee is required to ensure that the mitigation plan is fully implemented. The financial guarantee shall be posted in accordance with ECDC section 23.40.290 ("Bonds to Ensure Mitigation, Maintenance, and Monitoring"). The financial guarantee must be in the amount of 120 percent of the estimated cost of the uncompleted actions or the estimated cost of restoring the functions and values of the critical area that are at risk, whichever is greater. Therefore, the financial guarantee for this project will be approximately $7,080.60 (the final guarantee amount should be based on an actual bid for the mitigation project, not the estimate). USE OF THIS REPORT This Critical Area Study and Mitigation Plan is supplied to Kent Dietz as a means of determining and protecting on-site critical areas, as required by the City of Edmonds. This report is based largely on readily observable conditions and, to a lesser extent, on readily ascertainable conditions. No attempt has been made to determine hidden or concealed conditions. The laws applicable to critical areas are subject to varying interpretations and may be changed at any time by the courts or legislative bodies. This report is intended to provide information deemed relevant in the applicant's attempt to comply with the laws now in effect. This delineation and report conforms to the standard of care employed by wetland ecologists. No other representation or warranty is made concerning the work or this report and any implied representation or warranty is disclaimed. Jim Rothwell Senior Ecologist, PWS Wetland Resources, Inc. Wetland Resources, Inc. 17 Dietz — Daley Street August 10, 2015 WRI Project # 15 101 REFERENCES Brinson, M.M. 1993. AJJydXpq!p0iq),hic Q.1assification for Wetlands, Technical Report WRPDE-4. US Army Engineers Waterways Experiment Station, Vicksburg, MS, Code Publishing Company, lognen&ode, http://www.codepublishing.com/wa/edmonds/. Seattle, WA Cowardin, L.M., V. Carter, F.C. Golet and E.T. Laroe. 1979. Classification " on " of We " dmmm_ands and Deep Water Habitats of the United States. U.S. Fish and Wildlife Service. FWS/OBS 79/31. . Water Environmental Laboratory. 1987. M Wedand Delineation Manual. Technical Report Y-87-1. Environmental Laboratory, Department of the Army, Corps Waterways Experiment Station, Vicksburg, MS. Liclivar, R.W. 2013. The National Wetland Plant List: 2013 Nvetland 11,'ttirig�. Phytoneuron 2013-49: 1-241. Published July 17, 2013. ISSN 2153 733X Munsell Color. 2012. Munsell Soil Color Book. Munsell Color, Grand Rapids, MI. Snohomish County Planning and Development Services (PDS) Si Sc al crySnoh(')1pJs'b '.9 -y q_cq,! ,s/snosgkpL1. U.S. Army Corps of Engineers (Corps). 2010. jtcg'J.L Wetland Delineation Manual: Western Mountaii1sLajtgys and Coast o Version_10.)... U.S. Army Engineer Research and Development Center Environmental Laboratory. Vicksburg, MS. Publication # ERDC /EL TR -10-3. U.S. Fish and Wildlife Service. National Wetland Wetlands Mapper. .11,111, ------ ----- . . . ........ ..... .. tLt(T)://www.fws.ggywe,tlai-kds/. USDA-NRCS. Web Soil Surve (liqtpL/ /HontePage lifila). Y Washington State Department of Ecology, U.S. Army Corps of Engineers Seattle District, and U.S. Environmental Protection Agency Region 10. Marcy 2006. Wetland Mitigation in Washington State - Part 1: Agency Policies and Guidance (Version 1). Washington State Department of Ecology Publication #06-06-011 a. Olympia, WA. Washington State Department of Ecology, U.S. Army Corps of Engineers Seattle District, and U.S. Environmental Protection Agency Region 10. Marcy 2006. Wetland Mitigation in Washington State - Part 2: Developing Mitigation Plans (Version 1). Washington State Department of Ecology Publication #06-06-011 b. Olympia, WA. Washington State Department of Fish and Wildlife (WDFW). PHS on (lie Web. (htqL.1/wvdfw v" /ma,�pjng/p Washington State Department of Fish and Wildlife (WDFW). 2011. Salrno iSc nla)i)iiiLy/saIrTIODSCa,)e/ind(- N-JI—Arril). Wetland Resources, Inc. 18 Dietz - Daley Street August 10, 2015 WRI Project # 15 101 UTM= Site Photos Looking north at Shell Creek and the box culvert. Planting area #I is on the right side of the stream. Upstream view of Shell Creek. View from top of landslide hazard area towards Shell Creek. The top of the box culvert is visible in the upper left of the photo. View of off-site portion of Shell Creek and buffer on adjacent, eastern parcel. Existing Conditions Map EXISTING CONDITIONS MAP DIETZ - DALEY STREET PORTION OF SECTION 24, TOWNSHIP 27N, RANGE 03E, W.M, DALEY STREET ... y0p __ Y�P:M, C4 A—V41- 11,,..30 l � .w.. LASTING ...._ yw... DOX g CuLvEyn 9D 6' ww m � �N 4 a �w+ar C4u aea mn;cn I STREAM BUFFER - �q p' � ararwv�ar �I" �` �FPIhiWNUd x.11 p f l 0 '00 100 w 1tt Scale 1" = 20' Site Plan and Mitigation Map SITE PLAN & MITIGATION MAP DIETZ - DALEY STREET PORTION OF SECTION 24, TOWNSHIP 27N, RANGE 03E, W.M. N Ik GABtON I WALLS POWER CONNO AT SIDE OF MM �w w, "w TO BE Scale 1" = 20' I 10 291 �0. 40 A DALEY STREET 11011 CULVERT "y 90.01 � 4 FOOT .. BRIDGE SPLIT -RAMI. r FENCE a 1 'Ile EXISTING NATIVE * ✓ VEGETATION TO REMAIN Dc- .., �, THROUGHOUT BUFFER 1 100 -FOOT STREAM BUFFER OF ASPHALT N T 'STREAM BUFFER COMPRISES ENTIRETY OF PROPERTY OUTSIDE OF SPLIT -RAIL FENCE. "EROSION CONTROL BMP'S MUST BE INSTALLED AROUND AREA OF DISTURBANCE UNTIL CONSTRUCTION ACTIVITIES ARE COMPLETE. 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