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Home My WebLink AboutWetland Buffer Mitigation Plan - PLN General - 12/30/2010 THE WETLAND CORPS Wetland Delineation • Habitat Management Plans • Riparian Restoration • Mitigation • Biological Evaluation Parcel 223315000063 Wetland Buffer Mitigation Plan Collins Lake #1 TR 63 Tahuya, Wa Prepared for: Steven Dameron c/o Rock Harbor Construction PO Box 8118 Lacey,Wa 98509 Prepared by: Lee Boad and Heather Lane December,2010 AV THE WETLAND CORPS 1�_ Wetland Delineation - Habitat Management Plans - Riparian Restoration - Mitigation - Biological Evaluation Table of Contents PROJECTDESCRIPTION........................................................................................I PROPERTYDESCRIPTION.....................................................................................1 APPLICABLESETBACKS.......................................................................................2 ANALYSISOF EFFECTS..........................................................................................2 MITIGATIONMEASURES ......................................................................................3 MONITORING............................................................................................................5 SUMMARY..................................................................................................................5 REFERENCES.............................................................................................................7 Figures Figure 1. Site Vicinity Map Figure 2. Site Map Figure 3. National Wetland Inventory Map Figure 4. Mason County Soil Survey Map Figure 5. DNR Water Resource Map AV THE WETLAND CORPS Wetland Delineation - Habitat Management Plans - Riparian Restoration - Mitigation - Biological Evaluation December, 2010 Project#TWCIOW319 Page 1 of 7 Parcel 223315000063 Wetland Buffer Mitigation Plan Collins Lake#1 TR 63 Tahuya,Wa PROJECT DESCRIPTION The details of a Wetland Buffer Averaging proposal and Mitigation Plan for the above referenced property (Parcel Number 223315000063) are discussed in full in this report. The property is located in Section 31, Township 23 North, Range 02 West, off of Creekview Place within the Collins Lake Subdivision (Figure 1 Vicinity Map). The entire ownership is approximately one acre in size. The purpose of this proposal is to address the proposed construction of a single-family residence (SFR) partially within the buffer of a Category II Wetland with low habitat function. The wetland requires a buffer of 90 feet with an additional 15-foot building setback according to Tables 17.01.070 E & F of the Mason County Resource Ordinance. The required wetland buffer occupies the majority of the property. A driveway to the proposed building area already exists within the property. It will need to be widened to facilitate construction access. This will require selective tree removal for which mitigation has also been prescribed. The home site is proposed in a location that is the furthest distance from the wetland feasible while meeting the development objectives. The SFR is proposed approximately 80 feet from the wetland at the nearest point. Mitigation for construction of the home partially within the buffer will be addressed by increasing the buffer on the opposite side of the wetland. The objectives of this report are as follows: ■ To evaluate the potential adverse effects to critical area functions resulting from the establishment of the SFR and widening of the access road within the wetland buffer. ■ To outline mitigation measures necessary to offset the adverse affects resulting from the establishment of the SFR and widened access road within the wetland buffer. SITE DESCRIPTION The parcel is bordered to the east by Creekview Place. Residential parcels of similar size border the ownership to the north, south and west. Topography within the property consists generally of moderate slopes towards a depressional wetland system located in the south central portion of the property. An existing road grade runs generally along the northern property line. The property is well forested with a partially cleared area to the west of the wetland. PO Box 2854, Belfair, WA 98528 cell:370-620-0618, Office: 370-372-2421 e-mail: wetlandcorps@hotmail.com Wetland Buffer Averaging Proposal and Mitigation Plan TWC No.IOW319 December,2010 Page No.2 The wetland is characterized by a dense vegetative community of spirea and slough sedge with willow and alder along the fringe. The upland portion of the property consists primarily of a Douglas fir overstory with an understory of salal, evergreen huckleberry and scattered patches of Himalayan blackberry. APPLICABLE SETBACKS The project site is within the jurisdiction of Mason County. Ordinance 17.01.070 identifies Wetland Areas adopted by Mason County. The applicable setback for this project is as follows: Habitat Type Buffer Building Setback from Buffer Category II Wetland(MHF) 90, 15' ANALYSIS OF EFFECTS A portion of the project falls within the regulated buffer of a category II wetland. Project scale in the protected area is as follows: Development Type Habitat Type Portion of project within buffer SFR Category II Wetland buffer 176 sq. ft. of covered porch Vegetation Disturbance The area within the buffer to be occupied by a portion of the house is comprised of a shrub community of evergreen huckleberry and salal within a Douglas fir dominated stand. The majority of the building area is outside the 90-foot buffer. There are 15 to 20 Douglas firs (6"-14" DBH) located within the buffer that will need to be removed to achieve construction oriented access as well as establish the necessary grade for the building site. As the property is densely forested, the necessary tree removal is not of a scale that will substantially modify the overall forested nature of the buffer. Portions of the trees removed will be used as nurse log habitat along the wetland edge. Designated Critical Habitat for Salmonids Designated Critical Habitat for Salmonids is not within the vicinity of the project area. Therefore, none of the proposed actions are likely to destroy or adversely modify designated critical habitat. Actions described in this plan are not expected to jeopardize the continued existence of any listed species. Noise Pollution A slight increase in noise from construction activities is likely to occur during daylight construction hours. No nesting sites are located within the radii of concern that would be impacted by noise associated with the proposed work. PO Box 2854, Belfair, WA 98528 cell:370-620-0618, Office: 370-372-2421 e-mail: wetlandcorps@hotmail.com Wetland Buffer Averaging Proposal and Mitigation Plan TWC No.IOW319 December,2010 Page No.3 Temporary Increase in Sediment and Turbidity During Construction The proposed work has the potential to temporarily increase turbidity and suspended sediment within the project area. Best Management Practices have been perscribed to minimize the adverse effects associated with sediment and turbidity during construction. Light and Glare The proposed project will result in an increase in light and glare commonly associated with residential construction and land use. The vegetative buffer to be preserved and enhanced between the proposed project and the wetlands is expected to shield the majority of the wetlands from increased light and glare. Given the existing development within the surrounding area, resident wildlife species have most likely become locally adapted to light and glare associated with residential construction and use. MITIGATION MEASURES Preservation of Critically Important Plants The remainder of the wetland buffers, outside of the project area will be preserved. The buffer associated with the wetland is well forested and will be avoided to the extent feasible. Minimization Mitigation The proposed project minimizes impacts to the wetland buffer by positioning the SFR the furthest distance that the overall configuration of the property will allow, given all other setback requirements. The total square footage of the proposed building footprint is 1920 sq ft, of which only 176 sq ft falls within the standard 90-foot buffer. Best Management Practices Recommended Best Management Practices for this project are as follows: • Perform excavation and site preparation work during dry weather. • Install silt fencing between the work area and the wetland to prevent erosion and siltation of waters (See diagram below). • Minimize amount of erodible soils at any given time to the maximum extent feasible. • Check all equipment daily for leaks. Refueling and lubrication of equipment should occur off site. Do not store any fuel, lubricants, chemicals, or hazardous substances outside overnight within the project area. • Do not apply any chemicals when there is a possibility of rain. • Comply with all permits and requirements of governing authority. PO Box 2854, Belfair, WA 98528 cell:370-620-0618, Office: 370-372-2421 e-mail: wetlandcorps@hotmail.com Wetland Buffer Averaging Proposal and Mitigation Plan TWC No.IOW319 December,2010 Page No.4 3' HIGH CONSTRUCTION STEEL POST FENCE J ��p11 �-_gL01f IG Er WM SPACING WITH WIRE SUPPORT FENCE 6 FT NM SPACING MIRgUT WIRE SUPPORT FENCE FILTER FABRIC PONOING HT. STEEL.POST /TO UHF CURELY SIDE 0 RUNOFF T 12'MIN. kmv 6"TRENCH WITH COMPACTED BIICNFlLL Silt Fence Diagram Silt fence Installation The presence of exposed soil associated with site preparation work poses a risk of erosion and siltation to the wetland during storm events. It is recommended that silt fencing be installed between the work areas and the wetland to avoid siltation. The silt fence should be inspected and repaired if necessary after each storm event. Sediment should be removed from the fence and deposited to an area that will not contribute to regulated waters. The fence can be removed once the project is complete and soil has stabilized. Nurse Log Placement Overstory trees greater than 10-inches DBH removed from the portion of the project area within the buffer should be placed elsewhere within the buffer to provide nurse log habitat. The logs should be segmented into 10-15 foot pieces to facilitate transport. The logs should be i natural distribution. A to should be kept of placed randomly throughout the buffer to mimic atura g p the total number of trees removed from the project area and placed as nurse logs. Buffer Averaging To mitigate for the 10-foot reduction in the western wetland buffer necessary for the placement of the SFR, the eastern portion of the buffer will be increased by ten feet resulting in a total buffer width of 100-feet on the eastern side of the wetland (Figure 2). As required by Chapter 17.01.070. Section 5 of the Mason County Resource Ordinance, the overall surface area of buffer within the property will be equivalent to what is currently in place. Also required is that measures be implemented to increase the overall function and value of the wetland. This will be done via the prescribed buffer enhancement outlined below. PO Box 2854, Belfair,WA 98528 cell:370-620-0618, Office: 370-372-2421 e-mail: wetlandcorps@hotmail.com Wetland Buffer Averaging Proposal and Mitigation Plan TWC No.IOW319 December,2010 Page No.5 Buffer Enhancement Currently,the area located directly west adjacent to the wetland contains a vegetative plot partially occupied by Himalayan blackberry as well as a small clearing. It is recommended that the Himalayan blackberry be uprooted and taken off site and the cleared area be planted with Douglas fir seedlings spaced approximately 10-feet apart. The overall area to be enhanced occupies approximately 500 sq ft. Installing 10-douglas fir seedlings in this area should be sufficient to meet the intent of enhancing the function of the buffer, given the limited scale of impact being addressed (176 sq ft of building within buffer). MONITORING Monitoring of the site will begin the first fall following project completion and maintained on a seasonal basis. The information gathered will provide the following: 1) condition of installed plant species; 2) the quantity and overall status of nurse logs placed within the buffer; 3) any disturbance caused by the development and its effect on the protected zone and associated aquatic habitat; 4) any occurrence of exotic species within the Buffer Enhancement Zone; 5) any corrective measures that may be deemed necessary to provide desired conditions. This monitoring will be in effect for the duration of five years as required by Chapter 17.01.070. The information gathered will be provided in an annual report and submitted to the Director of Mason County Department of Community Development. SUMMARY This mitigation report addresses the establishment of a SFR occupying an area of 1920 square feet, of which, 176 square feet will be within the regulated buffer of a category II wetland with low habitat function. Additional work includes removal of 10-15 overstory trees from the buffer necessary for construction access and establishment of a suitable grade for the construction site. The SFR is proposed 80 feet from the Category II Wetland while the majority of trees to be cut within the buffer are adjacent to an existing access road. (See Figure 2. Site Map). Best Management Practices are recommended to insure no negative impacts to aquatic habitat. Mitigation recommendations include nurse log placement,buffer averaging, and buffer enhancement via removal of invasive species and planting of Douglas fir seedlings. No impacts to water quality or aquatic habitat are predicted. Mitigation Measures, and Best Management Practices, have been identified to avoid, minimize, and mitigate for impacts associated with the proposed work. We trust this information is sufficient for your needs at this time. Thank you for choosing The Wetland Corps as your wetland consultant. If you have any questions feel free to call. PO Box 2854, Relfair, WA 98528 cell:370-620-0618, Office: 370-372-2421 e-mail: wetlandcorps@hotmail.com Wetland Buffer Averaging Proposal and Mitigation Plan TWC No.lOW319 December,2010 Page No.6 Respectfully submitted, Lee Boad Senior Ecologist Heather /010-( ther Lane Staff Wetland&Natural Resource Specialist PO Box 2854, Belfair, WA 98528 cell:370-620-0618, Office: 370-372-2421 e-mail: wetlandcorps@hotmail.com REFERENCES Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe, 1979. Classification of Wetlands and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service document FWS/OBS-79/31. 84 pp. Washington, D.C. Hitchcock, L.C. and A. Cronquist, 1973. Flora of the Pacific Northwest. University of Washington Press.. 730 pp. Hruby, T., 2004. Washington State Wetland Rating System for Western Washington—Revised. Washington State Department of Ecology Publication#04-06-025. eta Macbeth. New Windsor Mansell Soil Color Charts, 1998. Gr g ,New York. Pojar, J. and A. MacKinnon, 1994.Plants of the Pacific Northwest Coast. Lone PinePublishing. 528 pp. Vancouver, British Columbia. Speare-Cooke, S., 1997. A Field Guide to the Common Wetland Plants of Western Washington and Northwestern Oregon. Seattle Audubon Society. 417 pp. US Department of Agriculture, Soil Conservation Service. Soil Survey of Mason County Area, Washington. September, 1951. US Fish and Wildlife Service. National Wetlands Inventory. 1978. Washington State Department of Ecology, 1997. Washington State Wetland Identification and Delineation Manual. Ecology Publication#96-94, various pagination. Olympia, Washington. Washington State Department of Ecology, 1993. Washington State Wetlands Rating System, Western Washington Second Edition. 61 pp.Ecology Publication#93-74. �Olympia, Washin on. Washington State Department of Ecology, 1999. Methodsfor Assessi ng Wetland Functions for Reverine and Depressional Wetlands in the Lowlands of Western Washington. Ecology Publication#99-115. Olympia, Washington. United States Fish and Wildlife Service, 1993.National List of Plant Species that Occur in Wetlands Region 9—Northwest. Resource Management Group PO Box 2854, Belfair,WA 98528 cell:370-620-0618, Office: 370-372-2421 e-mail: wetlandcorps@hotmail.com 0 a S i �w Shoe Lake Erdman Lake co ad O� y li nsLaTNO ake ti�}q ,p Ph 4 2 P� a Z Approximate Parcel �� ,�; Location �P -y Z' rn Vr � ,I NE TRAIL IN Pickers Pond Grass Lake Maggie Lake DryPond FIGURE I VICINITY MAP Project Name: Parcel 223315000063 Wetland Delineation Location: Tahuya,Washington Project: TWC10-W76 THE WETLAND CORPS Date:t•12/10 en Dameron Map Legend VA!�t /•u �`? �; Fish and Wildlite Service l�f n e CONUS Cities l��l�11�s7 II IVeI ll�t h + Fr (» kl CONUS 5tatas 104K ? .- Lower 1$Wetland Polygons Estuarine and Marine O"gwaler Estuarine and Marine Welland ,� .Y c�. �t`t _ 4 �!�` j %f�4+F°' 'k�l'�7e�t��'? R+�y 5►!1a. ` a 1• freshwater Enwirgent Wetland i-reshwater forested'Shrub Wetland k, - r i reshwater Pond Approximate -- '�, t Lake Parcel Location Other 14 Nlverine 10 Ir VA i t e ` ate(} . 1 •t r K i` Awl Figure adapted from NWI Figure 3 National Wetland Inventory Map Section 31 Township 23 North Range 2 West Mapper website FIGURE 3 NWI MAP Project Name: Parcel 223315000063 Wetland Delineation Location: Tahuya,Washington Project: TWC10-W76 Client: Steven Dameron THE WETLAND CORPS Date: 12/10 + 76 _ IW . •�1. _,� '` r ,�. ", Approximately', rj ! r t' �' * ~ f ,Nr Parcel Location - x ' 4t ,! fe j 1 f P � � t .ter t� Onsite Soil Conditions based on Mason County Soil Survey Subject Site Soils: Ab -Alderwood gravelly sandy loam, 5 to 15 percent slopes. The Alderwood series consists of brown, well-drained, upland soils. They have developed from mixed gravelly glacial till dominated by acid igneous rock. The imbedded gravel is mainly granite and quartzite. Rainfall is 45 to 60 inches a year. The native vegetation is a dense forest consisting almost entirely of Douglas-fir and a dense understory of salal, Oregon-grape, vine maple, and huckleberry. Northeast of the Hood Canal the understory is mainly rhododendron. Alderwood soils occupy the extensive rolling glacial moraines, and they are the dominant soils in the eastern part of the county. The Alderwood gravelly sandy loam, 5 to 15 percent slopes (Ab) is the most extensive, soil of the Alderwood series. It occupies undulating to rolling moraines. FIGURE 4 SOIL SURVEY Project Name: Parcel 223315000063 Wetland Delineation JAW Location: Tahuya,Washington Project: TWC10-W76 THE 'W ETL__"_N D CORPS Client: Steven Dameron Date: 12/10 Note: Hydric soils not present in project vicinity. , e 1709204 170820 +708 F + 8300 + V__F Erdman Lake ` 707282 1707284 +707288 +707288 1707380 + r Approximatef� F Cullins Lake parcel location � K 17 262 1707264 1707266 17 ,2M = +707380 �N +, + + + F _� rr F^� 10 1O 000 c SOILS Hydtic Soils IRE•CMS Highly Unstable TRANSPORTAUON r Stream Water Type 1-5(East side) Highly Erodible /%#0PaVed Road Highly Unsmbiefi ,�� LT11p1VedROad Stream Type Unknoiim(East side) H:glily Erodible �N �,► Stream Water Type 1-5((West side) No Data or Gravel Pits �..o Road(Surface i_TtAmox-v71) /v ll ,-�•�''Stream Type Unknown(West side) _-abandoned Road ' c-lrphanetl Road Trail FIGURE 5 DNR STREAM MAP Project Name: Parcel 223315000063 Wetland Delineation Location: Tahuya,Washington Project: TWC10-W76 ti► Client: Steven Dameron THE 1 TTL__"_N D CORP-'-, Date: 12/10 Note: One stream mapped southwest of project vicinity. Parcel b_ � � � � , Vie Ma Owner Information !STEVEN R DAMERON 3280 PINE RD NE APT 56 BREMERTON WA 98310-2109 Taxpayer Information STEVEN R DAMERON 3280 PINE RD NE APT 56 BREMERTON WA 98310-2109 Legal Description COLUNS ',EKE T1 TR63 Site Address Reval Area �' 2 County Zoning View Zoning Land Size* 0.00 Field Sheet ' IFS 05489: Tax Code ' 262 Land Use �' VACANT LAND 5 ACRES & UNDER Census Tract Click Here Tax Code Description :' 1 403 D P3 F2 L H2 ' if the value is _00(zero)then the property is most likely in a plat and acreage is not usually carried on platted lots