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HomeMy WebLinkAbout2006.07.13 - Supplemental Information to Wetland Review at Discovery VillageALKAI CONSULTANTS, LLC. Environmental Engineering • Geotechnical Engineering - Wetland Consulting July 13, 2006 Lander Custom Designed Homes Attn: Rick Lander PO BOX 65437 Port Ludlow, WA 98365 ACL05W 162 Page 1 of 3 Supplemental Information to Wetland Review at Discovery Village, Port Townsend, Washington This letter provides supplemental information to the Wetland Review at Discovery Road and Eddy Street, Port Townsend, Washington completed by Alkai Consultants, LLC ( Alkai) in September 2005. Specifically, information regarding classification and potential project impacts to of off- -site wetlands is provided. Previous studies The city of Port Townsend Public Works Department commissioned a field study to determine wetland areas associated with the potential roadway alignments for the future extension of Howard Street Environmental Sensitive Wetland Area Study prepared by Loggy Soil and Wetland Consulting, 2005). Ten separate wetlands were identified, classified, and delineated on nine parcels. Per this report, wetlands associated with the Howard Street extension in the vicinity of the Discovery Village project site are rated as Category it and Category III wetlands and characterized as having low to moderate habitat and water quality functions- As such, existing buffer requirements for these wetlands is a maximum of 150 feet (PTMC 19.05.110.E.3.a). Application of this buffer width to the off -site wetland directly west of Eddy Street and north of Discovery Road would impact the subject property in the extreme southwest comer of the site. However, this buffer requirement may not impact the subject property due to specific provisions of the PTMC, including buffer waivers (PTMC 19.05.110.E.) and buffer reductions (PTMC 19.05.110.E.6). These provisions are reviewed in our letter to you dated September 9, 2005 (attached). Wetland classification On July 12, 2006 Alkai visited the project. site to classify the off -site wetland directly west of Eddy. Street and north of Discovery Road (see Wetland A, Figure 1) The wetland was rated using the state rating manual, Washington State Wetland Rating System for Westem Washington (Hruby 2004). This rating system identifies habitat attributes and various characteristics associated with the water quality and hydrologic functions of wetlands. The rating form completed for this wetland is attached to this letter. The off -site wetland was classified as a depressional wetland. This wetland has high water quality function, low hydrologic function, and low to moderate habitat function. Based on these functional attributes associated with the wetland, it has been rated as a Category III wetland, scoring 49 points on the state rating form. Category III wetlands have a standard buffer width requirement of 80 feet based on a high land use intensity (PTMC 19.05.110.E.3.a and b). 9465 Provost Road NW, Suite 202 9 Silverdale, Washington 98383 Phone: (360) 613 -2407 Fax: (360) 613 -2408 Wetland Assessment Port Townsend, Washington ACL05W 162 Page 2 of 3 Potential project impacts Potential project impacts to Wetland A include a decrease in habitat and water quality functions due to buffer reduction and increased stormwater runoff. A review of these potential impacts and how proposed site development plans mitigate for these impacts is provided below. As shown in Figure 1, the proposed project will impact the wetland buffer only it the extreme southeast comer of the site. The proposed asphalt road (Eddy Street) adjacent to the wetland is not anticipated to affect the wetland any more than the existing gravel road right-of-way, which is also directly adjacent to the wetland. It is not anticipated that wetland functions and values will be diminished with a small reduction in overall buffer size since the existing buffer is currently degraded due to the presence of Eddy Street and Discovery Road. Given these buffer characteristics, it is unlikely that the existing buffer currently reduces any adverse impacts of adjacent land uses to the east or south. Additionally, site development plans include an approximately 20foot wide landscape buffer between the wetland and Eddy Street that will serve to protect wetland function and provide habitat value and the intersection of Eddy Street and Discovery Road is aligned to avoid buffer impacts. Given these site development components, is not anticipated that the buffer reduction included in the proposed project will result in overall functional loss to either the buffer or the wetland. Site development plans have been designed to avoid and/or minimize potential project impacts to water quality functions due to increased stormwater runoff. These design elements include .low impact development (LID) techniques including a reduction in overall impervious surface area (by reducing road and sidewalk width) and the use of permeable paving. In addition, as noted above, site development plans include an approximately 20 -foot wide landscape buffer between the wetland and Eddy Street. This landscaped area, while not modeled to calculate inflow and detention capabilities, will be graded to create a small depression and have amended soil. As such, this area will provide some on -site surface stormwater infiltration and minimize surface flow into the wetland. As such, it is not anticipated that the proposed project will result in overall functional loss in water quality. Summary An off -site wetland was identified, classified, and delineated as part of a field study commissioned by the city of Port Townsend Public Works Department in relation to the potential roadway alignments for the future extension of Howard Street (Environmental Sensitive Wetland Area Study prepared by Loggy Soil and Wetland Consulting, 2005). Alkai subsequently categorized an off -site wetland directly west of Eddy Street and north of Discovery Road as a Class III depressional wetland using the state rating manual, Washington State Wetland .Rating System for Westem Washington. While the proposed project includes some wetland buffer reduction, site development plans have been designed to avoid and/or minimize potential project impacts and it is not anticipated that the proposed project will result in overall functional loss to water quality or habitat functions. Figure 1. Discovery Village 9465 Provost Road NW, Suite 202 a Silverdale, Washington 98383 Phone: (360) 613 -2407 Fax: (360) 613 -2408 Wetland Assessment Port Townsend, Washington ACL05W162 Page 3 of 3 9465 Provost Road NW, Suite 202 • Silverdale, Washington 98383 Phone: (360) 613-2407 Fax: (360) 613-2408 0 ALKAI CONSULTANTS, LLC. Environmental Engineering • Geotechnical Engineering • Wetland Consulting September 29, 2005 ACL05W 162 Page 1 of 7 Lander Custom Designed Homes Attn: Rick Lander PO BOX 65437 Port Ludlow, WA 98365 RE. Wetland Review at Discovery Road and Eddy Street, Port Townsend, Washington Dear Mr. Lander, Pursuant to your request, Alkai Consultants, LLC performed a wetland review of the property located at the corner of Discovery Road and Eddy Street within the city limits of Port Townsend, WA. This review was completed in anticipation of a proposed residential housing development consisting of approximately 60 single - family homes with access from both Eddy Street and Discovery Road. The subject property is comprised of a number of small parcels totaling 5.02 acres. The property is basically triangular in shape and located in the northeast portion of Section 9, Township 30N of Range 01W. The purpose of the review was to confirm the findings of the wetland review performed by Olympic Wetland Services in December 1995 with regard to the presence or non- presence of wetland conditions on the above- mentioned site. Wetland Specialist Christy Carr performed all fieldwork, review and reporting. The following is a summary of methodology and findings. Methods Field Review A field reconnaissance was conducted over the entire 5.02 -acre parcel, specifically; several small previously mapped wetlands were examined for wetland conditions. Field review was conducted on August 19, 2005. Wetland Analysis Wetland determination followed a routine methodology based upon the Washington State Wetland Identification and Delineation Manual (1997) requiring positive indicators for wetland soil, hydrology, and plants. The time of year and recent precipitation history were considered in assessing the type and extent of wetlands presumed to exist on site. Wetland hydrology was determined through observation of field indicators and by examining a small pit dug in the southwest corner of the property. The pit was examined for standing water, waterlines and soil saturation. Presence or non- presence of hydric soil was determined by soil conditions observed in a pit dug within the suspected wetland area. Soil inspection included comparison with the Munsell Color Charts 1992). General soil characteristics were derived from information contained within the Soil Survey of Jefferson County, Washington (1975). Occurrence of wetland vegetation was determined through species identification, estimation of i' dominance and then assignment of wetland indicator status. Indicator status was assigned based on the National List of Plant Species That Occur in Wetlands (1996). 9465 Provost Road NW, Suite 202 • Silverdale, Washington 98383 Phone. (360) 613 -2407 Fax. (360)613 -2408 Wetland Determination City of Port Townsend, WA ACL05W162 Page 2 of 7 Paper Review The potential for the presence of onsite and nearby wetland areas was assessed with available data from the City of Port Townsend and the US Fish and Wildlife Service, National Wetlands Inventory online wetlands mapper) (NWI). The NWI map shows no identified wetland areas onsite; however, the City of Port Townsend's Environmentally Sensitive Areas Composite Map (December 2003) (ESA map) shows a small wetland (approximately 7000 square feet in area) in the southwest corner of the property. A nearby wetland is located across Eddy Street to the west, known as the Howard Street Corridor and also appears on the ESA map. The potential onsite wetland was rated for type and category status to determine if the wetland might be exempt from provisions listed under the City of Part Townsend's Municipal Code. The nearby wetland was rated to determine if required buffers would potentially impact the subject property. Wetland rating was estimated using the Washington State Wetland Rating System for Western Washington (2004). Two additional sources of information were reviewed. These include a wetland study completed in May 2005 as part of.the City's proposed extension of Howard Street (Environmental Sensitive Wetland Area Study prepared by Loggy Soil and Wetland Consulting) and .a letter from Mr. Bill Roesler dated September 14, 2005. Results Field Review The small depressional wet[and that appears on the ESA map in the southwest corner of the property was analyzed. No other wetlands were observed on the site. Additional wetland areas shown in the wetland review performed by Olympic Wetland Services (1995) are either off -site to the east or thought to be. included in the mapped wetland included in this analysis. The small depressional on -site wetland is oval in shape located just south of the end of an abandoned ditch adjacent to Discovery Road on the south. Indicators for wetland soil, hydrology, and plants are discussed below. Jefferson County Soil Survey maps the onsite soil as Ciallam gravelly sandy loam, 0 to 15 percent slopes (CmC). -This nearly level to rolling soil is on terraces. Most slopes range from 5 to 10 percent. This soil is well drained. Permeability is moderate above the cemented layer. Roots penetrate to a depth of 20 to 40 inches. This soil holds about 2 to 4 inches of water available for plants. Runoff is slow to medium, and the hazard of water erosion is slight to moderate. The soil is saturated part of the time during the rainy season, and at times water moves laterally, in places, above the cemented layer. Most of the acreage of this soil is used for growing pasture of mixed grass and alfalfa or grass and clover. Home garden crops, berries, and vegetables are also grown. The soil profile exhibited non - distinct soil horizons with a low matrix chroma (Munsell reading. IOYR 312 at a 10 inch depth) and redoximorphic features (mottles). These soil features are consistent with positive indicators of hydric soil. The pit revealed redoximorphic features (mottles) indicating the potential for a fluctuating water table that is most likely driven by precipitation. No other potential indicators of wetland hydrology, such as soil saturation, watermarks or drift lines, were observed. The hydrologic analysis in the wetland review performed by Olympic Wetland Services (1995) reported standing water associated with the abandoned ditch where it abuts Discovery Road. This wetland review was completed in December — not during the growing season — during an above average year for rainfall. Given these characteristics, positive wetland indicators are not present. The vegetation found within the depressional area consists predominately of a dense.thicket of nootka rose. Lesser amounts of snowberry, Himalayan blackberry, pacific willow, white clover, and creeping 9465 Provost Road NW, Suite 202 • Silverdale, Washington 98383 Phone: (360) 613 -2407 Fax: (360) 613 -2408 Wetland Determination City of Port Townsend, WA ACL05W 162 Page 3 of 7 buttercup were also observed. The dominance of nootka rose (FAC) provides a positive indicator of wetland vegetation. Upland Assessment With the exception of the above - mentioned small depressional area, the entire site consists of grass upland with a few Douglas fir, alder, and ornamental apple trees scattered throughout the site. The western property line is delineated by a narrow strip of unmanaged scrub -shrub vegetation dominated by Himalayan blackberry. The upland areas do not exhibit any indicators of wetland conditions mainly due to vegetation composition. There is a single - family residence and several accessory buildings currently occupying the property. Paper Review The surrounding property consists of a residential community with undeveloped land to the west. Across Eddy Street to the west, there is a nearby wetland (Howard Street Corridor) with an estimated rating of Category Il. Per the Environmental Sensitive Wetland Area Study prepared for this area, the wetlands associated with the Howard Street extension in the vicinity of the subject property are rated as Category II wetlands and characterized as having low to moderate habitat and water quality functions. The letter written by Mr. Bill Roesler addresses the small depressional area in the southwest corner of the site and was analyzed for this review (Attachment A). Mr. Roesler states that he "had created a small retention pond area that would catch run -off from the rest of the property in anticipation of future development we planned.' Mr. Roesler asserts that this area was assessed by a wetland professional sometime during or around the year 2000 in conjunction with a building permit application for the subject property. The wetland assessment determined that the small depressional area did not exhibit any positive wetland indicators and, as a man - made pond, was not considered a wetland. An estimated rating for this small depressional area was determined to be Category IV. No threatened or endangered plant and animal species reside onsite or near the subject property. Wetland function and value scored low due to its small size and minimum capacity to hold or filter water. Regulatory Implications There are several regulatory implications to consider regarding the potential presence of wetlands and future development at the subject property. These include wetland determination, regulated wetlands, buffer requirements, and allowed activities and uses within wetlands. Each of these is discussed below. Wetland Determination Field review indicated positive wetland indicators for vegetation and soil. No positive wetland indicators for hydrology were observed. The Washington State Wetland Identification and Delineation Manual 1997) requires positive wetland indicators for vegetation, soil, and hydrology; therefore, the small depressional area examined on the subject property does not qualify as a wetland_ However, the City of Port Townsend has jurisdictional authority to make a final wetland determination. The small depressional area appears on the City of Port Townsend's ESA map as an approximately 7000 square foot wetland. If the presence of this wetland is confirmed by the City it would be considered a regulated wetland. Regulated Wetlands According to City of Port Townsend Municipal Code (PTMC), Category IV wetlands greater than 1000 square feet are regulated wetlands. However, the small depressionaf area may be an artificial wetland i.e. man - made). The depressional area is located at the end of an abandoned ditch just north of 9465 Provost Road NW, Suite 202 • Silverdale, Washington 98383 Phone: (360) 613 -2407 Fax: (360) 61 Wetland Determination City of Port Townsend, WA ACL05W162 Page 4 of 7 Discovery Road. The ditch may convey rainfall across the site which then accumulates at the edge of Discovery Road. Standing water observed in high rainfall years and wetland vegetation observed near Discovery Road may indicate that wetland conditions are created artificially by these constructed site features. The letter written by Mr. Roesler indicates that this small depressional area was created when he constructed a retention pond on the subject property for the purposes of stormwater conveyance. If the depressional area is confirmed by the City of Port Townsend as an artificial wetland it would be considered a non - regulated wetland (PTMC 19.05A 10.C.3). Wetland Buffers If the on -site depressional area is determined to be a regulated wetland, the PTMC requires a 50 -foot undisturbed buffer around the wetland to protect its functions and values (Figure 1). In addition, the nearby Howard Street Corridor wetland complex presents a potential regulatory implication. This wetland complex, located across Eddy Street, was delineated in May 2005 as part of the City's proposed extension of Howard Street (Environmental Sensitive Wetland Area'Study prepared by Loggy Soil and Wetland Consulting). Per this report, the wetlands associated with the Howard Street extension in the vicinity of the subject property are rated as Category 11 and Category III wetlands and characterized as having low to moderate habitat and water duality functions. As such, existing buffer requirements for these wetlands is 150 feet (PTMC 19.05.110.E.1a). Application of this buffer width would impact the subject property in the extreme southwest corner of the site (Figure 1). The buffer requirements for both on- and off -site wetlands may not impact the subject property due to one or both of the following provisions of the PTMC: f Buffer waivers Buffer waivers may be granted by the City under certain conditions as per PTMC 19.05- 110.E.8: Application of the buffers set forth in this section 19.05.110 may be waived by the director in instances where either of the following findings are made: a. The parcel to be developed lies landward of an existing and substantial structural development on an intervening lot which separates the parcel from the wetland and has effectively eliminated the function and value to be derived from the required buffer width; or b. The parcel to be developed lies landward of an existing constructed roadway which separates the parcel from the wetland and has effectively eliminated the function and value to be derived from the required buffer width n Subsection b, above, likely applies to the subject property as Eddy Street lies between it and the Howard Street Corridor wetland complex. Buffer reduction Buffers may be reduced administratively on a case -by -case basis per PTMC 19.05.110.E_6 where it can be shown that: i. No direct, indirect, short -term, or long -term adverse impacts to regulated wetlands will result from the proposed development activity; or ii_ The site is extensively vegetated and has less than 15 percent slopes; or iii. The project contains provisions to enhance buffers using native vegetation which will provide additional protection for the wetland's functions and values. In any 9465 Provost Road NW, Suite 202 • Silverdale. Washington 98383 Phone: (360) 613 -2407 Fax: (360) 613 -2408 Wetland Determination City of Port Townsend, WA ACL05W162 Page 5 of 7 case, buffers shall not be reduced to a width of fewer than 25 feet, unless this requirement would deny all reasonable use of the affected property as determined by the director pursuant to PTMC 19.05.050D 19.05.050(D). Allowed Activities and Uses within Wetlands Other areas of the PTMC address Category IV wetlands. Specifically, Section 19.05.110.D.4. permits activities and uses within Category IV wetlands as follows: Activities and uses that result in unavoidable impacts may be permitted in Category IV wetlands and associated buffers in accordance with an approved critical area report and compensatory mitigation plan, and only ifthe proposed activity is the only reasonable alternative that will accomplish the applicant's objectives. Full compensation for the loss of acreage and functions of wetland and buffers shall be provided under the terms established under the Mitigation subsection in this section 19.05.110." Summary An initial wetland review has been completed .by applying a methodology based upon the Washington State Wetland Identification and Delineation Manual (1997) requiring positive indicators for wetland soil, hydrology, and plants. A potential wetland was observed in the southwest corner of the property. Positive indicators for wetland soil and vegetation were observed-, however, wetland hydrology indicators were not present. The small depressional area appears on the City of Port Townsend's ESA map as an approximately 7000 square foot wetland. According to City of Port Townsend Municipal Code (PTMC), Category IV wetlands greater than 1000 square feet are regulated wetlands. There are also Category ll and III wetlands to the west of the property across Eddy Street. There are several regulatory implications of this wetland review, outlined below. ' If the presence of the depressional area is confirmed by the City of Port Townsend to be a wetland it would be considered a regulated wetland. This would result in either a 50 -foot undisturbed buffer required around the wetland (buffer averaging or buffer reduction may be granted by the city) or the allowance of the proposed development in accordance with an approved critical area report and compensatory mitigation plan. If the presence of the depressional area is confirmed by the City of Port Townsend to be an artificial wetland it would be considered a non - regulated wetland. No further wetland or regulatory review would be required. The required buffer for the Howard Street Corridor wetland may impact the site in the southwest corner. A buffer waiver may be granted by the City. We trust this information is sufficient for your needs at this time. Thank you for choosing us as your environmental consultant. If you have any questions, please feel free to call. Sincerely, Christy Carr" Wetland Specialist 9465 Provost Road NW, Suite 202 - Silverdale, Washington 98383 Phone: (360) 613 -2407 Fax. (360) 613 -2408 Wetland Determination City of Port Townsend, WA ACL05W 162 Page 6 of 7 Figure 1. On -site wetiand area and off -site wetland buffer. 0 100 200 300 400 Feet 9465 Provost Road NW, Suite 202 • Silverdale, Washington 98383 Phone: (360) 613 -2407 Fax: (360) 613 -2408 S A-H a Septcmber 14, 2005 Rick bander ` Wetland Determination City of Port Townsend, WA ACL05W162 Page 7 of 7 la response to yoiv requeA for claffiGatioll on the -watlwWs" issues surrounding the propWy at 23M Discovery Road, you will, rcmH that I gave you a copy of the wetbads report done by Dixie Llevxlyn prior to our building the houso aa who vmudd become 2110 Discovery Rand, which was canstrmted on. or about the year 2000 and iu response to the Uty's roquesi that we cW ify the veetkmds prior to their 'sssving a building ge=it. Dixie reviewed the `vedlande thst shoved on the rotmty maps at that time (on the east end o fthe property) and as izdkated in lxer report, the area has no wetlawls, soils of phws. The building pa-aa was issued accordingly. We also specifically had her took at the saute time at thB low area on the southwest corner ofthe pxnperty wilese we had creased a small retention pond area that would catch run -alffmm fio rest oftbz property in arxticipatzx of Future dcvekTmm we planned. She took a soil core and loop at the glsntM and found no `VeElanV Wications io that srca ofthe property either a ud indicated that a mart -wa& pond, espozWly that bad no water in tit, couldn't be comitlerrtd wetlands in any event. These hasn't been any vvatear to OW area for y=s so ks a hard to imagine }low it wi& show up as a weiand a'= on any city maps. Hapeftll3yttus will clarify the matter, to your sadsf an Uwe can be of any fmthcr help, please let us know. BM Roes2cr