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HomeMy WebLinkAboutSHX2009-00022 Drainage Improvements Hartstene Point - SHX Application - 5/19/2009 -------------------------------------------------------------------------------------------------------------- AGENCY USE ONLY Agency reference# Date received: Circulated by: Project Tracking#: -------------------------------------------------------------------------------------------------------------J 0 US Arm Co WASHINGTON STATE 0 Joint Aquatic Resources Permit Application Form mu oEngineesrps Seattle District Part 1—Project Identification 1a. Unique Project Identifier hel Don't have one yet?Get one at www.epermitting.wa.gov or call the Office of Regulatory Assistance at 1-800-917-0043. 763800-09-01 1 b. Project Name (Examples:Smith's Dock or Seabrook Lane Development) [hel Pointes Drive East Drainage Improvements Part 2—Applicant Person or organization legally responsible for the project. [I1e1p] 2a. Name (Last, First, Middle)and Organization (if applicable) Hartstene Pointe Maintenance Association 2b. Mailing Address (Street or PO Box) 202 Pointes Drive East 2C. City, State, Zip Shelton, WA 98584 2d. Phone(1) 2e. Phone(2) 2f. Fax 2 . E-mail (360) 426-2300 ( ) ( ) hpmabob@aol.com Part 3—Authorized Agent or Contact Applicants can authorize someone else to represent them. If you use an authorized agent or contact for this project, please fill out the section below. Authorized agent(s) must sign Part 10.b. of the JARPA. LheM 3a. Name (Last, First, Middle) and Organization (if applicable) Sellers, Harry, P.E., Gray& Osborne, Inc. 3b. Mailing Address (Street or PO Box) 701 Dexter Avenue North 3C. City, State, Zip Seattle, WA 98109 3d. Phone(1) 3e. Phone(2) 3f. Fax 3 . E-mail (206) 284-0860 ( ) (206) 283-3206 hsellers@g-o.com Form#23 1 of 15 Last Update:06118108 Part 4—Property Owner hel ® Same as applicant. (Please skip to Part 5.) ® Repair or maintenance activities on existing rights of way or easements. (Please skip to Part 5.) ❑ There are multiple property owners. (Please provide the information requested below for each property owner. Please attach an additional sheet to the form if necessary.) 4a. Name (Last, First, Middle) and Organization (if applicable) 4b. Mailing Address (Street or PO Box) 4c. City, State, Zip 4d. Phone(1) 4e. Phone(2) 4f. Fax 4g. E-mail Part 5—Property and Project Locations ❑ There are multiple properties or project locations (e.g., linear projects). For each property, please include the information below in an attachment. 5a. Street Address (Cannot be a PO Box. If there is no address, please provide other location information in 5k.) [hel Pointes Drive East on Hartstene Island 5b. City, State, Zip (If the project is not in a city or town,please provide the name of the nearest city or town.) [help] Shelton, WA 98584 5c. County hel Mason 5d. Please provide the section, township, and range for the project location. [hel 1/4 Section Section Township Range SW 19 21 North 1 West 5e. Please provide the latitude and longitude of the project location. hel ■ Example:47.03922 N lat./ -122.89142 W long Lat: 47.1064 North/Lon: 112.3068 West 5f. List the tax parcel number for the project location. [ne�] ■ The local county assessor's office can provide this information. Not Applicable ( 2-1 ICJ -- 50 _ i 5g. Identify the type of ownership of the property. (Check all that apply.)[hel ❑ State Owned Aquatic Land ❑ Tribal land ❑ Private land ® Other publicly owned land (federal, state, county, city, special districts like schools,ports, etc.) Form#23 2 of 15 Last Update:06118108 5h. Contact information for all adjoining property owners, lessees, etc. (If more space is needed, please attach a separate piece of paper.) h Name Mailing Address City, State,Zip Hartstene Pointe Maintenance 202 Pointes Drive East Shelton, WA 98584 Organization 5i. Is any part of the project area within a 100-year flood plain? hei ❑ Yes ® No 5j. Briefly describe the vegetation and habitat conditions on the property. nei The ravine near the intersection of Nantucket Road and Pointes Drive East conveys flow to Case Inlet via a narrow, eroding gully, which has undermined a number of large trees and threatens houses on the hilltop above the left bank of the stream. Second growth trees along the stream include Douglas fir, cedar and hemlock trees with a few alders, maples and willows. Stream habitat immediately downstream of the culvert conveying flow beneath Nantucket Road is too steep for salmonids to ascend and is being severely eroded by heavy flows during storm events. For approximately 75 yards downstream the gradient is steep enough to cause large trees to topple into the ravine. Once flows reach the toe of the slope the stream spreads out over the sandy deposits that have accumulated during the past five years. The lower portion of the streambed consists of sands and silts eroded from the ravine above. This portion of the stream has filled the floodplain by as much as 3 to 5 feet and there is little, if any, gravel in the streambed. Vegetation along the lower streambed is limited to grasses with a few larger trees back several feet from the ordinary high water mark. WDFW has determined that the lower portion of the stream is potential salmonid habitat extending to the downed trees along the lower portion of the ravine. Erosion caused by high flows through the ravine has reached the sand and gravel layer beneath the surface and threatens to undermine the steep ravine walls threatening homes above. The roadside ditch along Pointes Drive East is grass-lined with six 12-inch culverts along its 1,000-foot length. This ditch connects to an existing 21-inch CMP that extends to an outfall which discharges to Case Inlet just above MHHW,- this outfall is not passable to migratory salmonids. 5k. Describe how the property is currently being used. nei The stream and culvert passing under Nantucket Road convey stormwater to Case Inlet. The roadside ditch along Pointes Drive East conveys road runoff and stormwater from the surrounding area to Case inlet via the existing 21-inch CMP. 51. Describe how the adjacent properties are currently being used. [hei The area to the north of the stream through the ravine is a natural hillside with several large homes and out buildings on top. The area south of the stream through the ravine is a heavily forested natural area with walking trails along the edge. The area west of Nantucket Road is a fairly natural area with some residential development and other areas used for storage. The stream flowing under Nantucket Road and through the eroding ravine drains approximately one-half mile of the County Road south of the Hartstene Pointe Development. The overall land use in the area is residential. The area along the ditch next to Pointes Drive is a private roadway serving the Hartstene Pointe Development. m. Describe the structures (whether above or below ground) currently located on the property, including their purpose. Form#23 3 of 15 Last Update:06118108 There is a 24-inch CMP culvert conveying flow under Nantucket Road to the ravine that is eroding beneath the hillside to the north. There are several homes with out buildings at the top of this hillside that will be threatened by this erosion. The ditch along Pointes Drive East contains six 12-inch CMP storm culverts. There is an existing 21-inch CMP culvert that conveys flow from the Pointes Drive East ditch complex to Case Inlet. The stormwater outfall is located at an elevation of 22.00 feet, well above the Mean High Tide. 5n. Provide driving directions from the closest major highway to the project location, and attach a map. ■ Include other information about the property location (e.g. mileposts, river miles) hel The project area can be accessed from SR 3 via Pickering Road by taking a left onto East Hartstene Bridge Road and East North Island Drive which ends at the Hartstene Pointe gate. From the gate follow Barnacle Boulevard to East Pointes Drive East&East Nantucket Road. Part 6—Project Description 6a. Provide a very brief description of the overall project. hel The project involves improvements to the existing stormwater conveyance system. Work includes upsizing six 12-inch CMP storm culverts to 18-inches in the existing ditch along Pointes Drive East; this work will occur more than 200 feet from the OHWM of Case Inlet. Additional work will occur within an existing easement consisting of installation of approximately 174 LF of 18-inch culvert along an existing 21-inch CMP culvert, installation of a new storm vault, and replacement of the last 84 feet of the 21-inch pipe with 30-inch CPEP. The total length of work within the easement is 258 feet with the last (easternmost) 200 feet within shoreline jurisdiction. 6b. What is your project category? hel ■ Check all that apply. ® Commercial ® Residential ❑ Institutional ❑ Transportation ® Recreational ® Maintenance ❑ Environmental Enhancement & Restoration 6c. Please indicate the major elements of your project. ■ Check all that apply. Use"Other"to identify pertinent elements not listed. ❑ Aquaculture ® Culvert ❑ Ferry Terminal ❑ Pier/ Dock ❑ Bank Stabilization ❑ Dam /Weir ❑ Fishway ❑ Piling ❑ Boat Launch ❑ Dike/ Levee/Jetty ❑ Float ❑ Road ❑ Bridge ® Ditch ❑ Geotechnical Survey ❑ Scientific Measurement ❑ Bulkhead Device ❑ Dredging ❑ Marina/ Moorage ❑ Buoy ❑ Mining ❑ Stormwater facility ❑ Channel Modification ® Outfall Structure ❑ Utility Line ❑Other: 6d. Please describe how you plan to construct each project element checked in 6c. Include the specific construction methods and equipment that will be used. [Help] Form#23 4 of 15 Last Update: 06118108 ■ Identify where each element will occur in relation to the nearest waterbody. ■ Indicate whether each activity is within the 100-year flood plain. Ditch: The ditch along Pointes Drive East will be widened using hand tools and a back hoe. Culverts will be replaced using these tools and possibly a small crane. Culverts: The new 18-inch culvert will be installed parallel to the approximately 174 feet of the existing 21-inch pipeline between Pointes Drive East and Case Inlet using a backhoe or tracked excavator. A new storm vault will be installed at this point and the existing 21-inch pipeline between the storm vault location and Case Inlet will be removed and replaced with approximately 84 feet of 30-inch CPEP. Outfall: The total length of work within the existing easement is 258 feet with about 200 feet within Shoreline Jurisdiction. The existing pipe will be removed using a backhoe and hand tools and this same equipment, and a small crane or backhoe will be used to remove the existing 21-inch outfall pipe and install the new 30-inch pipe to Case Inlet. None of this work occurs within the 100-year floodplain. *Recreation: The Hartstene Pointe Maintenance Organization currently maintains a hiking trail system along the creek and ravine that is the subject of this application. This trail system is being threatened by erosion caused by high streamflows. If this project is not completed, it is likely that this recreational trail system will be closed to protect public safety. 6e. What are the start and end dates for the construction of the project? (monthiyear) [help] ■ If the project will be constructed in phases/stages, attach an outline of the construction sequence and the timing of activities, including the start and end dates of each phase/stage. Start date: July 2009 End date: _August 2009 ❑ See attached 6f. Describe the purpose of the work and why you want or need to perform it. hel The purpose of the proposed project is to reduce severe erosion downstream of the culvert near the intersection of Pointes Drive East and East Nantucket Road. Currently, part of the stormwater within the Hartstene Pointe Development(and drainage from approximately 0.5 mile of the County Road) is directed through a ravine that discharges to Case inlet/Puget Sound. This stormwater conveyance has been in existence since the development was constructed around 1970. However, at some time within the past five years the stormwater flows through the ravine have breached the glacial till exposing softer sand and gravel soils to extreme erosion during storm events. During heavy storm events, large volumes of sand and gravels have been carried downstream to Case Inlet and the ravine has widened and deepened. Flows from the storm events have also undercut and felled large trees. A footbridge is located approximately 150 feet downstream of the bottom of the ravine. At least five feet of sediment has been deposited in the vicinity of the bridge. Currently, deposits of sand and gravel have accumulated to within two feet of the bottom of the footbridge, whereas ten years ago one could walk beneath the bridge decking. If left unchecked, stormwater erosion will continue to undermine the trees and walls of the ravine and will eventually threaten several local residences above the ravine. The intent of this project is to reduce the impact from storm events by diverting water to the existing ditches along Pointes Drive East and on to an up-sized outfall to Case Inlet. Form#23 5 of 15 Last Update:06118108 6g. Fair market value of the project, including materials, labor, machine rentals, etc. heI $50,000 6h. Will any portion of the project receive federal funding? [hLeM ❑ Yes ® No ■ If yes, list each agency providing funds. 6i. Compliance with the State Environmental Policy Act (SEPA) !ei ■ Check the box(s) below that applies to the project. ■ For more information about SEPA, go to www.ecy.wa.gov/programs/sea/sepa/e-review.html. ❑ A copy of the SEPA determination or letter of exemption is included with this application. ® A SEPA determination is pending with Mason County(lead agency); expected decision date is June 2009. ❑ I am applying for a Fish Habitat Enhancement Exemption. Please submit the Fish Habitat Enhancement Project form with this application. ❑ This project is exempt. ❑ Categorical Exemption. Under what section of the SEPA administrative code (WAC) is it exempt? ❑ Other: [El SEPA is pre-empted by federal law. Part 7—Wetlands: Impacts and Mitigation If the project will not impact wetlands or wetland buffers, please skip to Part 8. 7a. Will the project impact wetland buffers? mm ❑ Yes ® No 7b. Will the project impact wetlands? [heM ❑ Yes ® No 7c. Describe how the project has been designed to avoid and minimize adverse impacts to wetlands. heI 7d. If you have already worked with any government agencies to reduce or avoid impacts, please list them below. [hei Name Agency Phone Most Recent Date of Contact Gloria Rogers WDFW (360) 753-2600 ext. 249 January 2009 7e. Has a wetland delineation report been prepared? [heM ❑ Yes ❑ No ■ If yes, submit the report with the application. Include copies of delineation data sheets. 7f. Have the wetlands been rated using the Washington State Wetland Rating System? [heiip] ❑ Yes ❑ No ❑ Not applicable ■ If yes, submit the wetland rating forms, including figures,with the application. Form#23 6 of 15 Last Update:06/18/08 7g. Have you prepared a mitigation plan to compensate for the project's adverse impacts to wetlands? [help] ❑ Yes ❑ No ❑ Not applicable ■ If yes, submit the plan with the application. 7h. For each project activity that will adversely impact wetlands, list the type and rating of each wetland to be impacted, the extent and duration of the impact, and the type and amount of compensatory mitigation proposed. If you are submitting a compensatory mitigation plan that includes a similar table, you may simply state (below) the page number in the mitigation plan where this information can be found. Ewipl Activity causing Wetland Type and Impact Area Duration of Proposed Wetland Mitigation Impact(filling, Rating Category' (sq ft. or acres) Impact2 Mitigation Type Area (sq ft. or draining, flooding, acres) etc. Ecology wetland category based on current Western Washington or Eastern Washington wetland rating system. If impacting wetlands, please include copies of wetland rating forms with application. 2 Indicate the time(in months or years, as appropriate)the wetland will be measurably impacted by the work. Enter"permanent"if applicable. 3 Creation (C), Re-establishment/Rehabilitation (R), Enhancement(E), Preservation(P), Mitigation Bank/In-lieu fee(B) Reference to a similar chart/table in mitigation plan, if available. 7i. Provide a summary of what the compensatory mitigation plan is intended to accomplish, and describe how a watershed approach was used to design the plan. hei 7j. For all filling activities identified in 7h., please describe, in detail, the source and nature of the fill material, the amount that will be used, and how and where it will be placed into the wetland. hel 7k. For all excavating activities identified in 7h., please describe the type of material proposed to be excavated, the methods to be used, the amount of material to be removed, and where the material will be disposed. hel Form#23 7 of 15 Last Update:06118108 Part 8. — Waterbodies (other than wetlands): Impacts and Mitigation If the project will not impact waterbodies or areas around waterbodies, please skip to Part 9. 8a. Will your project impact a waterbody or the area around a waterbody? [help] ® Yes ❑ No 8b. Summarize the impact(s) to each waterbody in the following table. hel Activity causing Waterbody Impact Duration of Amount of Area (sq ft. or Impact(clearing, name location' Impact2 material to be linear ft.) of dredging, filling, placed in OR waterbody directly pile driving, etc.) removed from affected waterbody Storm flow diversion Creek Between Permanent, None Approximately 400 from creekflowing flowing Nantucket during storm linear feet through ravine through Rd. & events ravine Case Inlet Storm flow diversion Ditch Entire Temporary Ditch will be Approximately to ditch along draining length during maintained and 1,000 linear feet of Pointes Drive East Pointes along construction existing 12-inch ditch along Pointes Drive East Pointes (1 month) & culverts will be Drive East. Drive E. permanent replaced with 18- during storms inch pipes New 18-inch Unnamed 175 feet Approx. two Will require None. stormwater pipeline ditch& between weeks during approx. 350 square between Pointes culverts to Pointes construction. feet of excavation Drive&new storm Case Inlet Drive E Stormwater parallel to existing vault and new improvement 21-inch culvert. Storm permanent. Vault Installation of storm Outfall Same Approx. 1 None. The new 30- Pipe will terminate vault and replacing flows to location week during inch outfall pipe at an elevation of 22 84 feet of 21-inch Case Inlet as construction will be installed in feet, well above the pipe with 30-inch existing &permanent the same alignment MHH tide in Case CPEP outfall pipe. 21-inch stormwater as the existing 21- Inlet. culvert improvements inch pipe. Indicate whether the impact will occur in the waterbody, or provide the distance to the waterbody and indicate whether it will occur within the 100-year flood plain. 2 Indicate the time(in months or years,as appropriate)the waterbody will be measurably impacted by the work. Enter"permanent"if applicable. 8c. Describe how the project has been designed to avoid and minimize adverse impacts to the aquatic environment. hei The project has been designed to reduce the stormwater flows into the stream flowing through the eroding ravine. Flows above the 10-year event will be diverted into the ditch and culvert system along Pointes Drive East where they will be directed to the new outfall to Case Inlet. Flows greater than the 10-year event(and local groundwater) will continue to flow down the ravine. The new 30-inch outfall pipe will be installed in the same alignment as the existing 21-inch pipe. The new outfall pipe will terminate and discharge at the same location as the existing pipe well above the HHW of Case inlet, which will minimize impacts to marine biota in the vicinity. 8d. Have you prepared a mitigation plan to compensate for the project's adverse impacts to non-wetland waterbodies? [help] ❑ Yes ® No ❑ Not applicable ■ If yes, submit the plan with the application. Form#23 8 of 15 Last Update:06118108 8e. Provide a summary of what the compensatory mitigation plan is intended to accomplish, and describe how a watershed approach was used to design the plan. If you have already completed T, you do not need to restate your answer here. hel Diversion of storm flows away from the eroding ravine will protect the integrity of the streambed and minimize erosion of the banks above the stream, which should protect homes, outbuildings and the hiking trail at the tops of these slopes. 8f. Please describe in detail the source and nature of the fill material, the amount that will be used, and how and where it will be placed into the waterbody. hel Not applicable. No fill will be introduced into either Case Inlet or the unnamed stream draining through the eroding ravine. Implementation of this project will reduce the amount of erosion occurring in the ravine and filling the stream habitat between the ravine & Case Inlet. 8g. For excavating or dredging impacts, please describe the type of material proposed to be excavated or dredged, the methods to be used, the amount of material to be removed, and where the material will be disposed. Lne�] Not applicable. Part 9—Additional Information Providing answers to the questions below is optional, but will help the review of your application. 9a. What is the zoning designation for the project location? [help]You can get this information from the local city or county planning department. ■ Zoning designation examples include, but are not limited to, residential, rural, agricultural, and general commercial. Rural Residential 9b. What US Geological Survey Hydrological Unit Code (HUC) is the project in? [help] • Go to http://cfpub.epa.gov/surf/locate/index.cfm to help identify the HUC. HUC 1711001900335 9c. What Water Resource Inventory Area Number (WRIA#) is the project in? hel ■ Go to www.ecy.wa.gov/services/gis/maps/wria/wria.htm to find the WRIA WRIA#14 Shelton Basin Form#23 9 of 15 Last Update:06118108 9d. Are any of the waterbodies identified in 7h. or 8b. on the WA Dept. of Ecology 303(d) List? hel ❑ Yes ® No ■ If yes, list the parameter(s) below. • If you don't know, use WA Dept. of Ecology's Water Quality Assessment tools at: http://www.ecy.wa.gov/programs/wq/303d/. 9e. For in-water construction work, will the project comply with the State of Washington water quality standards for turbidity (WAC 173-201A)? LtIeU ® Yes ❑ No 9f. If the project is within the jurisdiction of the Shoreline Management Act, what is the local shoreline Environment designation? [,zip] Rural ■ If you don't know, contact the local planning department. ■ For more information, go to: www.ecy.wa.gov/programs/sea/sma/laws_ruies/173-26/211—designations.html. ® Rural ❑ Urban ❑ Conservancy ❑ Natural ❑ Other 9g. What is the Department of Natural Resources Water Type? (Check all that apply.)[hel • Go to http://www.dnr.wa.gov/BusinessPermits/Topics/ForestPracticesApplications/Pages/fp_watertyping.aspx for the Forest Practices Water Typing System. ® S Case Inlet ® F Lower portion of unnamed creek draining the ravine. ® Np Upper portion of creek draining the ravine ® NS Roadside ditch along Pointes Drive East 9h. Will this project be designed to meet the WA Dept. of Ecology's most current stormwater manual? net ® Yes ❑ No ■ If no, and it is designed to a different manual, provide the name of the WA Dept. of Ecology approved manual the project is designed to meet. 9i. If you have any historical knowledge of what the property was used for before identifying it for this project, lease describe it below. hel The property in the immediate project area has been used for stormwater conveyance since the early 1970s. 9j. Has a cultural resource survey been performed on the project area? hel ❑ Yes ® No • If yes, please attach to your application. Form#23 10 of 15 Last Update:06118108 Part 10—Authorizing Signatures 10a. Applicant Signature (required) I certify that to the best of my knowledge and belief, the information provided in this application is true, complete, and accurate. I also certify that I have the authority to carry out the proposed activities, and I agree to start work ONLY after I have received all necessary permits. I hereby authorize the agent named in Part 4 to act on my behalf in matters related to this application. (initial) By initialing here, I state that 1 have the authority to grant access to the property. I also consent to the permitting agencies entering the property where the project is located to inspect the project site or any work (initial) Applicant Date 10b. Authorized Agent Signature I certify that to the best of my knowledge and belief, the information provided in this application is true, complete, and accurate. 1 also certify that 1 have the authority to carry out the proposed activities and I agree to start work ONLY after all necessary permits have been issued. Authorized Agent Date 10c. Property Owner Signature I consent to the permitting agencies entering the property where the project is located to inspect the project site or any work These inspections shall occur at reasonable times and, ifpractical, with prior notice to the landowner. a c')'A'I — petty ne Date 18 U.S.0§1001 provides that: Whoever,in any manner within the jurisdiction of any department or agency of the United States knowingly falsifies, conceals,or covers up by any trick,scheme,or device a material fact or makes any false,fictitious,or fraudulent statements or representations or makes or uses any false writing or document knowing same to contain any false,fictitious,or fraudulent statement or entry,shall be fined not more than$10,000 or imprisoned not more than 5 years or both. Form#23 11 of 15 Last Update:06118108 Part 11—Submitting the Completed JARPA Form Instructions: 1. Use the checklist below to indicate which permits you are applying for. 2. Make copies of the JARPA form and send it to the appropriate agencies. Remember to include any necessary attachments: • Complete construction drawings and specifications along with any maps and photos to support your description. These must be in 8 '/2 x 11 format. ■ A SEPA decision letter is required for a complete application to the Washington Department of Fish and Wildlife. The Department also requires two complete copies of all application documents. If your application contains more than 25 pages, also include digital files of all application documents on a CD or other digital storage media. ■ If applicable: • Wetland delineation report and copies of delineation data sheets. • Wetland rating forms, including figures. • Mitigation plan. 3. If it is not clear what permit(s) you need for the project, use the resources below: ■ Online Project Questionnaire at http://apps.ecy.wa.gov/opas/. ■ Office of Regulatory Assistance at 1-800-917-0043 or assistanceCc)-ora.wa.gov Identify the permits you are applying for: (Check all that apply) Shoreline permits: ❑ Substantial Development ❑ Conditional Use ® Shoreline Exemption ❑ Variance Send to: Appropriate city or county planning, building, or community development department. Other city/county permits: ❑ Floodplain Development Permit ® Critical Areas Ordinance Send to: Appropriate city or county planning, building, or community development department. ® Hydraulic Project Approvals Send to: Department of Fish and Wildlife ® Section 401 Water Quality Certifications Send to: Department of Ecology regional office- Federal Permit Unit ❑ Aquatic Resources Use Authorizations Send to: Department of Natural Resources regional office Department of the Army permits: ❑ Section 404 (discharges into waters of the US) ❑ Section 10 (work in navigable waters) Send to: US Army Corps of Engineers United States Coast Guard permits: ❑ General Bridge Act Permit ❑ Private Aids to Navigation (for non-bridge projects) Send to: United States Coast Guard 1 UMI MLJ 14 VI I J LOOL IJpumu. VU/I U/VU Mailing Addresses and Contact Information Mailing location for Shoreline permits Send to: Appropriate city or county planning, building, or community development department. • For city and county contact information, go to: http://www.ora.wa.gov/today.asp Mailing location for Hydraulic Project Approvals Send to: Department of Fish and Wildlife ■ If you are NOT requesting emergency or expedited processing, please submit applications to the Headquarters office in Olympia. ■ If you are requesting emergency or expedited processing, please submit applications to the appropriate Regional office. Headquarters: Washington State Department of Fish Receives all applications when and Wildlife . Tel (360) 902-2534 emergency or expedited processing is Habitat Program TDD (360) 902-2207 NOT being requested 600 Capitol Way North Fax (360) 902-2946 Olympia, Washington 98501-1091 Regions: Receives all applications for emergency or expedited processing Region 1 Washington State Department of Fish (Pend Oreille, Ferry, Stevens, Spokane, and Wildlife Tel (509) 892-1001 Lincoln, Whitman, Columbia, Garfield, 2315 North Discovery Place Fax (509) 921-2440 Asotin, and Walla Walla Counties) Spokane, WA 99216 Region 2 Washington State Department of Fish (Okanogan, Douglas, Grant, Adams, and and Wildlife Tel (509) 754-4624 Chelan Counties) 1550 Alder Street NW Fax (509) 754-5257 Ephrata, WA 98823-9699 Region 3 Washington State Department of Fish (Franklin, Kittitas, Yakima, and Benton and Wildlife Tel (509) 575-2740 Counties) 1701 South 24th Avenue Fax (509) 575-2474 Yakima, WA 98902-5720 Region 4 Washington State Department of Fish (Whatcom, Skagit, Snohomish, King, and Wildlife Tel (425) 775-1311 Island, and San Juan Counties) 16018 Mill Creek Boulevard Fax (425) 338-1066 Mill Creek, WA 98012-1296 Region 5 Washington State Department of Fish (Lewis, Wahkiakum, Cowlitz, Skamania, and Wildlife Tel (360) 906 -6700 Clark, and Klickitat Counties) 2108 Grand Blvd. Fax (360) 906-6776 Vancouver, WA 98661-4624 Region 6 Washington State Department of Fish (Pacific, Pierce, Thurston, Grays Harbor, and Wildlife Tel (360) 249-4628 Mason, Jefferson, Clallam, and Kitsap 48 Devonshire Road Fax (360)664-0689 Counties Montesano, WA 98563-9618 Form#23 13 of 15 Last Update:06118108 Mailing location for 401 Water Quality Certification Send to: Department of Ecology regional office-Federal Permit Unit ■ For a map of Ecology Regional Offices, go to: www.ecy.wa.gov/org.html Headquarters Mailing Address P.O. Box 47600 Olympia, WA 98504-7600 Tel (360)407-6000 Physical Address 300 Desmond Drive Lacey, WA 98504 Central Region 15 West Yakima Avenue, Suite 200 Tel (509) 575-2490 Yakima, WA 98902-3401 Fax 509 575-2809 Eastern Region 4601 North Monroe, Suite 202 Tel (509) 329-3400 Spokane, WA 99205-1295 Fax 509 329-3529 Northwest Region 3190 - 160th Avenue S.E. Tel (425) 649-7000 Bellevue, WA 98008-5452 Fax 425 649-7098 Southwest Region Mailing Address: P.O. Box 47775 Olympia, WA 98504-7775 Tel (360)407-6300 Physical Address: Fax (360)407-6305 300 Desmond Drive Lacey, WA 98504 Mailing location for Aquatic Resources Use Authorizations Send to: Department of Natural Resources regional office • For a map of DNR regional offices, go to: http://www.dnr.wa.gov/ContactDNR/Pages/Home.aspx Headquarters Tel 360 902-1100 Northwest Region Tel 360 856-3800 Pacific Cascade Region Tel 360 577-2025 South Puget Sound Region Tel 360 825-1631 Northeast Region Tel 509 684-7474 Southeast Region Tel 509 925-8510 Olympic Region Tel 360 374-6131 Form#23 14 of 15 Last Update:06118108 Mailing location for Department of the Army Permits Send to: US Army Corps of Engineers Seattle District US Army Corps of Engineers Regulatory Branch Tel (206) 764-3495 P.O. Box 3755 Fax(206) 764-6602 Seattle, WA 98124-3755 Mailing location for General Bridge Act Permits and Private Aids to Navigation (for non-bridge projects) Send to: United States Coast Guard Section 9 Bridge Permit Commander 13th Coast Guard District Tel (206) 220-7282 (OAN) Fax(206) 220-7265 915 Second Avenue. Room 3510 Seattle, WA 98174-1067 Attn: Bridge Administrator Private Aids to Navigation Commander 13th Coast Guard District Tel (206) 220-7285 (OAN) Fax (206) 220-7265 915 Second Avenue, Room 3510 Seattle, WA 98174-1067 Attn: PATON Manager Form#23 15 of 15 Last Update:06118108 c4c5i Gray Osborne, Inc. RECEIVED CONSULTING ENGINEERS i� MAY 2 7 DW DATE: May 22,2009 M CCD - PLANNING TO: Mason County Community ATTN: Grace Miller Development Planning Department Shoreline Planner PO Box 279 Shelton,WA 98584 FROM: Jim Dougherty PROJECT#: 09452 SUBJECT: Transmittal of Summary Report: Evaluation of Shoreline Conditions at Hartstened Pointe,Mason,Washington WE ARE TRANSMITTING: THE FOLLOWING: FOR: ® Herewith ❑ Prints ❑ Review&Comment ❑ Under Separate Cover ❑ Construction Drawings ❑ Approval ❑ Specifications ❑ Signature Number of Copies: 1 ❑ Shop Drawings ® Your Use&Files ❑ Change Order ❑ As Requested ❑ Legal Description ❑ Action Noted Below ❑ Letters ❑ ® Summary Shoreline ❑ Evaluation for Hartstene Pointe COMMENTS: Ms. Miller: Harry Sellers requested that I forward a copy of the Summary Report:Evaluation of Shoreline Conditions at Hartstene Pointe prepared by Tubbs Geosciences for the Hartstene Pointe Maintenance Association.This report is being forwarded to you regarding the proposed Pointes Drive East Drainage Improvement Project.Harry Sellers has provided you with a copy of the JARPA Form prepared for this project. Feel free to contact Harry Sellers PE or me with questions regarding this important project. 701 Dexter Avenue N.,Suite 200 Seattle,Washington 98109 (206)284-0860 Fax:(206)283-3206 TO BE COMPLETED BY APPLICANT EVALUATION FOR AGENCY USE ONLY 15. Public services a. Would the project result in an increased need for public services(for example:fire protection,police protection,health care,schools,other)? If so,generally describe. No. b. Proposed measures to reduce or control direct impacts on public services,if any. None required. 16. Utilities a. Circle utilities currently available at the site: electricity,natural gas,water,refuse serv- ice,telephone,sanitary sewer,septic system,other. Storm conveyance exists. b. Describe the utilities that are proposed for the project,the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Improvement in the storm conveyance facilities are proposed. C. SIGNATURE The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: Date Submitted: 11 TO 131_COMPLE II=D BY APPLICANT EVALUATION FOR AGENCY USE ONLY I S. Public services a, Would the project result in an increased need for public services(for example: fire protection,police protection,health care,schools,other)? If so,generally describe. No. b, Proposed measures to reduce or control direct impacts on public services,if any. None required. 16. Utilities a. Circle utilities currently available at the site: electricity,natural gas,water,refuse serv- ice,telephone,sanitary sewer,septic system,other. Storm conveyance exists. b. Describe the utilities that are proposed for the project,the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Improvement in the storm conveyance facilities are proposed. C. S16NATURI; The above answers are true and complete to the best of my knowledge. I understand that the lead agency is relying on them to make its decision. Signature: Date Submitted: J� 1 11 TO BE COMPLETED BY APPLICANT EVALUATION FOR AGENCY USE ONLY D. SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (do not use this sheet for project actions) Because these questions are very general,it may be helpful to read them in conjunction with the list of the elements of the environment. When answering these questions,be aware of the extent the proposal,or the types of activities likely to result from the proposal,would affect the item at a greater intensity or at a faster rate than if the proposal were not implemented. Respond briefly and in general terms. 1. How would the proposal be likely to increase discharge to water;emissions to air,production, storage,or release of toxic or hazardous substances;or production of noise? Proposed measures to avoid or reduce such increases are: 2. How would the proposal be likely to affect plants,animals,fish,or marine life? Proposed measures to protect or conserve plants,animals,fish,or marine life are: 3. How would the proposal be likely to deplete energy or natural resources? • Proposed measures to protect or conserve energy and natural resources are: 4. How would the proposal be likely to use or affect environmentally sensitive areas or areas designated (or eligible or under study)for governmental protection;such as parks,wilderness,wild and scenic rivers,threatened or endangered species habitat,historic or cultural sites,wetlands,floodplains,or prime farmlands? Proposed measures to protect such resources or to avoid or reduce impacts are: 5. How would the proposal be likely to affect land and shoreline use,including whether it would allow or encourage land or shoreline uses incompatible with existing plans? Proposed measures to avoid or reduce shoreline and land use impacts are: 12 TO BE COMPLETED BY APPLICANT EVALUATION FOR AGENCY USE ONLY 6. How would the proposal be likely to increase demands on transportation or public services and utilities? Proposed measures to reduce or respond to such demand(s)are: 7. Identify,if possible,whether the proposal may conflict with local,state,or federal laws or requirements for the protection of the environment. 13 SON CO Ok MASON COUNTY �. rp Shelton (360) 427-9670 DEPARTMENT OF COMMUNITY DEVELOPMENT Belfair (360) 275-4467 Planning Mason County Bldg. 1 411 N.5th Elma (360) 482-5269 P.O.Box 279 Shelton,WA 98584 1IR TO BE KEPT IN THE PARCEL FILE August 20,2009 John Konovsky Squaxin Island Tribe Natural Resources Dept. 2952 SE Old Olympic HWY Shelton, WA 98584 Dear John, Enclosed please find the additional information that Mason County requested and has received from Gray &Osborne Engineering regarding drainage improvements for the Harstine Pointe Maintenance Association. Because the proposal meets the Dept of Ecology's 2005 Stormwater Management Manual for Western Washington,the Shoreline Exemption and Mitigated Determination of Nonsignificance have been conditionally issed to comply with the County regulations. Please review the submitted information and let me know if you have any comments.Thank you. Sincerely, A4 A44-te Grace Miller,Planner DEPT OF COMMUNITY DVEELOPMENT ��- TO BE KEPT IN TF IC Gray Osborne, Inc. t /�►+ i j," „ CONSULTING ENGINEERS RECEIVED August 11, 2009 AUG 13 2009 MCC D - PLANNING Ms. Grace Miller Mason County Department of Community Development P.O. Box 279 Shelton, Washington 98584 SUBJECT: ADDITIONAL INFORMATION REGARDING DRAINAGE IMPROVEMENTS HARTSTENE POINTE MAINTENANCE ASSOCIATION, MASON COUNTY, WASHINGTON G&O #09452.00 Dear Ms. Miller: In response to your request for additional information regarding water quality and the proposed drainage improvements at Hartstene Pointe, Leigh Nelson, P.E., prepared a memorandum addressing water quality facility design. Two copies are attached. Her memorandum covers a biofiltration swale, wet facilities, StormFilter cartridges, and Filterra treatment units. These facilities would treat stormwater runoff from a County road and a portion of the Hartstene Pointe development. None of the alternatives appears to be feasible, either due to space limitations or cost. The biofiltration Swale would need to be approximately 16.4 feet wide and about 2 feet deep. Representatives of the Squaxin Tribe mentioned the Americast Filterra unit as an alternative. It would appear,however, that this alternative is intended to treat relatively small flows in urban settings,rather than the rural environment at Hartstene Pointe. Our estimated cost for treatment with Filterra units is $660,000. More information about this system can be found at www.filterra.com. Information from Ecology is also attached to this letter. The purpose of this project is to divert flow from a badly eroded ravine, where stormwater runoff is continuing to wash sands, gravels, and silt into Puget Sound (see letter dated June 26, 2009). This flow will be diverted to an existing ditch, upsized to accommodate the higher flows. Typically, water quality treatment is required only when redevelopment occurs. We are not proposing any redevelopment or increase in impervious surface. The project addresses only existing conditions. That said,the 701 Dexter Avenue N., Suite 200 Seattle,Washington 98109 (206)284-0860 Fax (206)283-3206 4 Printed o recycled paper Ms. Grace Miller August 11, 2009 Page 2 proposed drainage improvements with the gravel bottom and grass sides will provide enhanced water quality compared with the existing ravine, where large quantities of loose sand and gravel will continue to be sluiced downstream and into Case Inlet. Rock check dams will be provided in steep sections of the ditch. This will slow the flow and allow more sediment to filter and settle. Please refer to the letter from Jim Andersen for a better description of existing conditions. Please call me at(206)284-0860 or e-mail me at hsellersgg-o.com if you have any questions. Very truly yours, GRAY & OSBORNE, INC. ka�-sCxj--X� Harry Sellers, P.E. HES/hhj Encl. cc: Mr. Bob Rabourn, Manager, Hartstene Pointe Maintenance Association �r ra Pnntetl on recycled paper Gray � Osborne, Lnc. -y�- _ O CONSULTING ENGINEERS r B� KEPT IN 701 DEXTER AVENUE NORTH SUITE 200 � HE SEATTLE. WASHINGTON 98109 •(206) 284-0860 �j L R-A t-j .E MEMORANDUM TO: FROM: Leigh K. Nelson, P.E. DATE: August 3, 2009 SUBJECT: Water Quality Facility Design Hartstene Pointe Maintenance Association Drainage Improvements (G&O# 09452) The following provides the design for facilities meeting the criteria for Basic Water Quality Treatment as outlined in Washington State Department of Ecology's 2005 Stormwater Management Manual for Western Washington (2005 DOE Manual) for the proposed Drainage Improvements along Pointes Drive East. The purpose of the Drainage Improvements is to divert flow from a badly eroded ravine where high flows through the ravine wash sediment down the channel. The sediment accumulates at the mouth of channel where it flows into Puget Sound. The runoff treatment BMPs that are evaluated to treat the diverted flow include a biofiltration swale, wetpool facilities (pond, vault and tank), StormFilter cartridges and Filterra treatment units. The Drainage Improvements receive flow from Drainage Basin No. 1, as delineated in the May 1997 Hartstene Pointe Comprehensive Drainage Plan/Slope Stability Analysis. This basin covers an area of approximately 38 acres, 20 of which are within the development of Hartstene Pointe. The area contains approximately 5,200 feet of roadway that is 20 feet in width. There are approximately 38 lots and one clubhouse (15,320 square feet) within the basin. It is assumed that average impervious cover of the lots is 2,200 square feet (1,200 square feet of roof and 1,000 square feet driveway). The remainder of the Basin is undeveloped and forested. Table I summarizes the land cover within Basin No. 1, the tributary area to the Drainage Improvements. August 11, 2009 Page 2 Table 1 Land Cover Tributary to Draina a Im rovements Areas Area ac Roadway 104,000 2.39 Rooftop Clubhouse 15,320 0.35 Single-Family Residences 83,600 1.92 Driveways 38,000 0.87 Forest 1,414,360 32.47 otal 1,655,280 1 38.0 Per the USDA Soil Survey of Mason County, the soil within Basin No. 1 is Sinclair Shotty loam. This soil type is within Hydrologic Soil Group C. As determined using the Western Washington Hydrology Model (WWHM), the 15- minute On-Line Water Quality flow rate for Basin No. 1 is 1.80 cfs and the 24-hour volume is 2.9 acre-feet. Flow frequencies calculated by the WWHM may be seen in Table 2. Table 2 Flow Frequencies from the WWHM Return Frequency Flow cfs 2-Year 3.54 5-Year 4.76 10-Year 5.57 25-Year 6.61 50-Year 7.39 100-Year 8.18 Biofiltration Swale Per the proposed construction plans, the proposed swale has a vegetated length of 764 feet. The swale is separated in several areas by six individual 18-inch diameter driveway culverts, the lengths of which are not included in the swale length. The overall slope is 4.11%. Because this is greater than 2.5%, check dams must be installed at vertical drops of 12-15 inches. It is assumed that the swale will be mowed infrequently such that a Manning coefficient of 0.24 and a depth of 4 inches are appropriate. August 11, 2009 Page 3 Per the 2005 DOE Manual, the maximum velocity at the water quality flow rate is 1 fps and for stability is 3 fps. Because high flows (those above the 2-year flow of 3.54 cfs) will bypass the swale, the 2-year flow was used in the Stability Check in lieu of the 100- year flow. The maximum allowable side slope is 3H:1 V. The minimum freeboard above the high flow rate is 0.5 feet. The minimum channel width that will allow for a velocity of 1 fps at the water quality flow rate is 4.4 feet. This channel width results in a depth of 0.43 feet at the stability flow rate, resulting in a total swale depth of 0.93 feet and a total minimum width of 9.95 feet. Because 18-inch diameter culverts connect the swale, the minimum depth of the channel is 2 feet. This results in a minimum top width of 16.4 feet. It is not feasible to construct a swale this wide along Pointes Drive East. Wetpool Facilities (Pond, Vault and Tank) Wetpool facilities are designed to have a"dead" storage volume equal to the 24-hour volume of the water quality event, as determined by the WWHM. They may be in the form of a pond, vault or tank. That volume is 2.9 acre-feet for Basin No. 1. The 2005 DOE Manual states that a wetpond must have a maximum depth of 8 feet. Accordingly, a wetpond designed to treat runoff from Basin No. 1 must have a minimum surface area of 15,790 square feet(0.36 acres). The 2005 DOE Manual states that the maximum depth of a vault is 20 feet, resulting in a minimum internal surface area of 6,316 square feet. Equivalently, if 6-foot diameter pipe were used as a tank, 4,468 lineal feet would be required. Due to site limitations, none of these options are feasible. StormFilter The CONTECH StormFilter has received a General Use Level Designation by DOE for Basic Treatment. Under the designation, the 18-inch diameter, 22-inch tall filter cartridges are approved at a maximum flow rate of 9.0 gpm/cartridge. The water quality flow rate of 1.8 cfs (808 gpm)would require 90 cartridges. The vault required to contain the cartridges would have a surface area of approximately 500 square feet and installed cost of approximately$400,000. It is not feasible to locate a facility of this size within the project area. Americast's filterra The filterra unit has received Conditional Short-Term Use Level Designation for Basic Treatment. Under the designation, the units have been approved at a flow rate of 50 inches per hour(0.00116fps). The water quality flow rate of 1.8 cfs would require a August 11, 2009 Page 4 treatment area of 1,555 square feet, or 44 of the standard 6' x 6' filterra units. It should be noted that these units are typically installed in urban areas with small drainage basins (less than 15,000 square feet each) and may not be appropriate for treating flow from Basin No. 1. It is not feasible to locate 44 of these units within the project area of the Drainage Improvements. The cost of each filterra unit is approximately$10,000. Including installation and associated costs,the total cost of treatment via filterra units is approximately$660,000. wA SH I N G i0N SLAT 0 E PAHi 11E Ni OF E C O L O G Y November 2006 CONDITIONAL SHORT-TERM USE LEVEL DESIGNATION FOR BASIC (TSS) & PHOSPHORUS TREATMENT PILOT USE LEVEL DESIGNATION FOR ENHANCED & OIL TREATMENT For Americast's filterra® Ecolo�v's Decision: Based on Americast's submissions and recommendations by the Technical Review Committee, Ecology hereby issues the following use level designations: 1. A Conditional Short-Term Use Designation for Basic and Phosphorus Treatment. 2. A Pilot Level Use Designation for Enhanced and Oil Treatment. These Conditional Use Level Designations expire on November 1,2009 unless extended by Ecology, and are subject to the conditions specified below. The Pilot Use Level Designations expire on May, 1, 2010 unless extended by Ecology, and is subject to the conditions specified below. Ecology's Conditions of Use: filterra 12 units shall be designed, installed, and maintained to comply with these conditions: 1. Each filterra@ unit shall be sized using an infiltration rate of 50 inches/hour using the 15-minute water quality design flowrate (as specified in Ecology's most recent Stormwater Manual) as calculated using the latest version of the Western Washington Hydrology Model or other Ecology-approved continuous runoff model. 2. Each site plan must undergo filterra© review before the unit can be approved for site installation. This will ensure that site grading and slope are appropriate for use of a filterra© unit. 3. filterra®media shall conform to the following specifications: Media Specs 4. Maintenance includes removing trash and accumulated debris from the filter surface and replacing the mulch layer. Inspections will be used to determine the site-specific maintenance schedules and requirements. Maintenace procedures should follow those given in the most recent version of the filterra@ Installation,Operation, and Maintenance Manual 5. filterra® commits to submitting a QAPP for TRC review and Ecology approval by May 1, 2007 that meets the TAPE requirements for attaining a GULD for basic, phosphorus, enhanced, and oil treatment. QAPPs must be submitted for each site where the unit is to be used for enhanced and oil treatment. 6. Local jurisdictions must file a "Pilot Level Technologies Notice of Intent" form with the Department of Ecology prior to authorizing filterra@ for a Pilot Use Level application (units to be used for enhanced and oil treatment). 7. filterra® shall submit a TEER for TRC review for enhanced and oil treatment by November 1, 2009 and shall submit a TEER for TRC review for basic and phosphorus treatment by May 1, 2009. 8. filterra®may request Ecology to grant deadline or expiration date extensions, upon showing cause for such extensions. Lack of funds to complete the monitoring will not be viewed by Ecology as sufficient cause. 9. Discharges from the filterra® units shall not cause or contribute to water quality standards violations in receiving waters. m ' ... _.' Applicant: Americast Applicant's Address: 11352 Virginia Precast Road Ashland,VA,23005 Application Documents: • State of Washington Department of Ecology Application for Conditional Use Designation,Americast(September 2006) Applicant's Use Level Request: General Level Use Designation for Basic and Phosphorus Treatment and Conditional Use Level Designation for Enhanced Treatment and Pilot Use Level for Oil Treatment. Applicant's Performance Claims: Field testing and laboratory testing show that the filterra®unit is promising as a stormwater treatment best management practice and can meet Ecology's performance goals for basic and phosphorus treatment and has the potential to meet Ecology's goal for enhanced and oil treatment. Technical Review Committee Recommendations: The Technical Review Committee finds sufficient evidence that filterra®should be able to demonstrate,through additional field testing, that it will attain a General Use Level Designation (GULD) for basic, enhanced, and phosphorus treatment. Findings of Fact: 1. Field testing data are currently available for 9 storms in Virginia. 2. The field data showed an average removal of 75%for TSS with an average influent of 12.5 +/- 7.60, 64% for total zinc with an average influent of 0.04+/-0.02, and 52%for total phosphorus with an average influent of 0.11 +/-0.05. 3. Laboratory testing was performed on a scaled down version of the filterra®unit. The lab data showed an average removal from 83-91% for TSS with influents ranging from 21 to 320 mg/L, 82-84% for total copper with influents ranging from 0.94 to 2.3 mg/L,and 50- 61%for orthophosphate with influents ranging from 2.46 to 14.37 mg/L. 4. Permeability tests were conducted on the soil media. 5. Lab scale testing using Sil-Co-Sil 106 showed percent removals ranging from 70.1% to 95.5%for influent concentrations ranging from 8.3 to 260 mg/L. Remaining Issues or Concerns about the filterra®Technology: 1. There is currently no data regarding the removal of dissolved metals. Data must be obtained on the removal of dissolved copper and dissolved zinc. Ecology's performance goals for enhanced treatment assume the facility is treating stormwater with dissolved concentrations ranging from 0.003 to 0.02 mg/L and dissolved zinc ranging from 0.02 to 0.3 mg/L. It is recommended that Americast find sites with stormwater containing metals in these concentration ranges. 2. There is minimal information regarding the expected life of the media. Testing should be conducted to determine a maximum treatment life of the media with regards to TSS, metals,and phosphorus treatment. 3. There is minimal information available about the treatment capabilities of different plant species, testing should be completed at sites that contain different plants to determine if plant species plays a key role in pollutant removal ability. Contact Information: Applicant: Larry Coffman Americast 301-580-6631 Icoffman@filterra.com Applicant's Website: http://www.filterra.com Ecology web link: http://www.egywa.gov/programs/wg/stormwater/newtech/index.html Ecology: Mieke Hoppin Water Quality Program, (360)407-6435, mhop461 Aecy.wa.gov TRC: Dave Tucker,P.E. Kitsap County (360) 7337-7292, dtuckerna co.kitsap.wa.us Filterra Bioretention Systems: Products: Bioretention, Stormwater Treatment Page 1 of 3 Home ; About Filterra ; Products ; Design Assistance ; Contractor Support t PRODUCTS Products Filterra@ �. BacterraTIA San Diego Solution Product Schematic Options 3 _ N p 61 Project Profiles Maintenance Plant Selections Why Choose Filterra? White Paper FAQ To treat stormwater pollution, we incorporate trees and shrubs into our Filterra design to create a cost effective solution for your stormwater projects. Best Value. Filterra offers the most cost effective stormwater treatment system featuring low cost, and easy installation and maintenance. Regulatory Compliance. University of Virginia testing confirmed that Filterra meets or exceeds federal and state regulatory requirements for SE pollutant removal. Aesthetics. Landscaping enhances the appearance of your site making C it more attractive while removing pollutants. Maintenance Support.A one year maintenance agreement is included with the purchase of every unit. Versatility. Filterra is used for both new construction and urban retrofits. Filterra works well in many applications, including: . Streetscapes . Urban Settings • Parking Lots . Roof Drains . Highways . Combined Sewer Overflows (CSO) . Industrial Settings http://www.fiIterra.coni/index.php/product/ 7/20/2009 Filterra Bioretention Systems: Products: Bioretention, Stormwater Treatment Page 2 of 3 Filterra application, including flora selection and sizing. Adaptability. Filterra can be used alone or in combination with other Best Management Practices (BMPs). Selection. Filterra is available in various configurations to meet both standard and unique site conditions. It is well suited for ultra-urban environments, providing high removal efficiency for many toxic substances such as petroleum and heavy metals. Expected Pollutant Removals (Ranges varying with particle size, pollutant loading and site conditions) TSS Removal 85% Heavy Metal Removal 33% - Phosphorus Removal 60% - 70% 82% Nitrogen Removal 43% Predicated Oil & Grease >85/o http://,A,ww.fiIterra.com/index.php/product/ 7/20/2009 Filterra Bioretention Systems: Products: Bioretention, Stormwater Treatment Page 3 of 3 _.. . ....... ... ........ ..........._......................_......_ _... .......... .........----.........................__....... . Filterra is protected by U.S. Patents#6,277,274&#6,569,321. Other patents pending. Storinwater Solutions About Filterra I Products ( Stormwater Design Assistance I Contractor Support I Contac AMERICAST Filterra is a Division of Americast ( 11352 Virginia Precast Road Ashland, VA 23005 Related content:stormwater solutions,street trees,stormwater management,stormwater filtration,stormwater runoff,low irnpac http://www.filterra.com/index.plip/product/ 7/20/2009 Filterra Bioretention Systems: Products: Options, Stormwater Pollutant Removal Page 1 of 1 Home About Filterra Products ; Design Assistance Contractor Support j C PRODUCTS Home Products Options l Filterra® BacterraT" San Diego Solution a Product Schematic Options Project Profiles Maintenance Plant Selections Options White Paper FAQ Filterra is an attractive approach to treating stormwater using our standard landscape container. You can further enhance your projects appearance by selecting optional tree grates. These grates can match Your existing street furniture from nationwide suppliers (East Jordan Iron Works, Urban Accessories). You can also integrate surrounding landscaping such as sod, pavers or mulch with a Filterra recessed top slab. This maintains the high pollutant removal while minimizing the surface area of exposed concrete. SE . Tree Grates ......_... ...... • Recessed._To..ps Filterra is protected by U.S. Patents#6,277,274&#6,569,321. Other patents pending. Stormwater Solutions ( About Filterra I Productt�s�, I Stormwater Design Assistance I Contractor Support I Contac �. AMERICAST Filterra is a Division of Americast 1 11352 Virginia Precast Road Ashland, VA 23005 Related content: bioretention.stormwater filtration, low impact development.stormwater bacteria,surface water runoff:pollut, http://www.fi]terra.com/index.php/product/options/ 7/20/2009 w Filterra' QptionsORecessed Tops f I Ite rra Filterra` recessed tops allow a -all r"�i seamless integration using pavers, ., mulch or sod. NOTE: Recessed tops increase the 41 �3 ' depth of the Filterra`invert out. l Recessed top with mulch s Recessed top prior to shipping CLEANCUT TREE GRATE & FRAME & COVER STEEL FRAME 4" AN u 10 — 12.. s A iEl .. b � For additional information please contact your local Filterra sales representative. Eastern Zone:866-349-3458,Western Zone:877-345-1450. 2007 Filterra. June 18, 2009 To: Harry Sellers From: Jim Anderson RE: Cuttysark diversion project Harry, I had a conversation with Bob Raboum about the status of the project and he recommended I send you a note describing the erosion created when the first major erosion event occurred in 2007. I live on 464 E. Chesapeake which is about half way from the Little Lagoon and the North Spit. Any time we have protracted bouts of heavy rain the erosion plume, which is chocolate in color and approximately 100 feet wide, is carried all the way to the end of the North Spit. Also at low tide (minus) it's easy to see how much the beach has changed due to the increased erosion. Last year 2008 we also had another event in Cuttysark ravine which created another large plume,however a bit smaller is size. Since the erosion has cut through the Glacial Till in the Cuttysark ravine and is now into sand and pebbles any significant rainfall will produce more of the same erosion to Case Inlet. Regards, im Anderson Page 1 of 1 Grace Miller - Re: Hartstene Pointe Drainage From: Grace Miller To: Harry Sellers Subject: Re: Hartstene Pointe Drainage Harry, First, yes, the Shoreline Exemption stands as an Exemption rather than a shoreline permit because I did not receive comments from DOE opposing its issuance as an Exemption. Second, I did I receive a response letter from John Konovsky of the Squaxin Island Tribe on Thursday, July 16th. I was not here Friday, so I will forward his comments to you after this e-mail. The question that I have at this point is why you did not specifically address the filtration options as outlined by John in his first letter and why they will or will not work for this project? I know you explained that the grass-lined ditch and why there is erosion, etc..but why a system equivalent to the one suggested by the Tribe will or wont work for the site needs to be addressed. Staff is inclined to condition the permit to include a treatment system comparable to the one suggested by the Tribe. It would appear that the proposal should be revised to include some sort of treatment in the conveyance system to the beach. Staff can then amend the SEPA to reflect that request. Please let me know your thoughts on this issue. Thank you. >>> "Harry Sellers" <hsellers@g-o.com> 7/20/2009 11:49 AM >>> Grace, We received our HPA from WDFW for Hartstene Pointe. I can scan and e-mail a copy for your files. However, I was hoping there would be some additional information from the County. First, I believe the question of a shoreline exemption was up to Ecology. Second, as you know, the Squaxin Tribe had several comments which we addressed. However, I do not know if these responses were satisfactory. Let me know if you need anything further. Harry Harry Sellers, P.E. Gray & Osborne, Inc. 701 Dexter Ave N. Suite 200 Seattle WA, 98109 Ph(206)284-0860 Fx(206)283-3206 Electronic File Transfer- Note that these electronic files are provided as a courtesy only. Gray & Osborne, Inc. in no way guarantees the accuracy or completeness of the digital data contained within these files. Furthermore, Gray & Osborne, Inc. assumes no liability for any errors or omissions in the digital data herein. Anyone using the information contained herein should consult the approved or certified hard copy drawings or reports for the most current information available. about:blank 7/20/2009 Page 1 of 1 Grace Miller - Re: SEP2009-00041 t IHc From: Grace Miller PARCEL FILE To: John Konovsky Subject: Re: SEP2009-00041 John, Thank you for your comments. I will pass them on to the applicants. >> "John Konovsky" <jkonovsky@squaxin.nsn.us> 7/16/2009 2:05 PM >>> Grace, I have reviewed the June 29th, 2009 letter from Harry Sellers at Gray& Osborne to you. I do not concur with his conclusion that"there is nothing about the current ravine discharge that is a positive water quality benefit." The ravine, especially at the bottom in the sediment and gravel bar between the beach and ravine, do provide some filtering capacity to remove bacteria from the runoff. When that water is put into a pipe and discharged directly on the beach, all such treatment capacity is lost. My request remains to amend the SEPA to include some sort of treatment in the conveyance system to the beach. John Konovsky John Konovsky r S�I�S o' Gd Environmental Program Manager Squaxin Island Tribe 2952 SE Old Olympic Hwy Shelton, WA 98584 TEL (360) 432-3804 CEL (360) 490-1212 (NEW!) EMAIL jkonovsky@squaxin.nsn.us about:blank 7/16/2009 Page 1 of 1 Grace Miller- RE: Harstene Pointe From: "Jim Dougherty" 6111101 �;lD, Ott t 4 4&,,, S-VM43 To: "'Grace Miller"' (000)a8It-08(Qo Date: 6/16/2009 1:53 PM Subject: RE: Harstene Pointe 7 2;,30-Z7 1�f1-4j CC: "'Harry Sellers"' Hi Grace! Harry was thinking that there might need to be an improvement to the existing energy dissipation structure at the outfall site, given the increase in discharge volume. I'll ask around the Stormwater Group and talk to Harry regarding water treatment options. How long does it usually take to go through the Substantial Development Permit process, once a Shoreline Exemption has been issued? Jim -----Original Message----- TO BE KEPI IN THE From: Grace Miller [mailto:Gbm@co.mason.wa.us] PARCEL � Sent: Tuesday, June 16, 2009 1:04 PM AV To: jdougherty@g-o.com Subject: Fwd: Harstene Pointe Jim, Attached are the comments that I have received from the Squaxin Island Tribe for the Harstine Pointe project. Part of the Tribe's issues are that a shoreline substantial development permit should have been required rather than an exemption. They are also stating that additional mitigation should be required. Are you and/or Harry Sellers able to comment regarding the increased stormwater runoff on the beach and nearshore zone? Can you submit additional proposed mitigation that will address the Tribe's concerns? I will talk to DOE about the exemption also. Thank you. fi le://C:\Documents%20and%20 Settings\gbm\Local%20 Settings\Temp\XPgrpwise\4A3 7A... 6/16/2009 rSox copes MASON COUNTY Shelton (360) 427-9670 DEPARTMENT OF COMMUNITY DEVELOPMENT Belfair (360) 275-4467 Planning Mason County Bldg.1 411 N.5th Elma (360) 482-5269 P.O.Box 279 Shelton,WA 98584 f85f TO BE KEPT IN THE July 6,2009 PARCEL FILE John Konovsky Squaxin Island Tribe Natural Resources Dept 2952 SE Old Olympic Hwy Shelton,WA 98584 Subject: SEP2009-00041,Harstene Pointe Maintenance Dear Mr.Konovsky, In response to your comments regarding Mason County's issuance of an MDNS for the Harstene Pointe Maintenance Association,staff requested that the applicant address your concerns.They have provided the enclosed responses and photographs to explain their project further. In response to your question for me as to whether the project qualifies for a shoreline exemption under normal maintenance and repair? After review of the project,I did determine that the portion of the project within shoreline jurisdiction qualifies as maintenance and repair and therefore issued it as a Shoreline Exemption.I sent the Exemption to the Department of Ecology and did not receive any comments from them so therefore can assume they concur with the determination. Please let me know whether your concerns have been addressed by the responses submitted by Gray& Osborne,Inc.for the HPMA.Please let me know if you have any questions.You can contact me at 427- 9670,ext 360 or gbm@co.mason.wa.us. Thank you. Sincerely, kr Grace Miller,Planner DEPT OF COMMUNITY DEVELOPMENT - W SQUAXIN ISLAND TRIBE 12 June 2009 TO BE KEPT IN THE Grace Miller PARCEL c Mason County Department of Community Development FILE POB 279 Shelton, WA 98584 SUBJECT: SEP 2009-00041, Harstene Pointe Maintenance Dear Ms. Miller, I am writing on behalf of the Squaxin Island Tribe to comment on the MDNS issued to the Harstene Point Maintenance Association. I visited the site on Tuesday morning, June 9th with Eric Sparkman, our shellfish biologist. Our review of the proposal raised two questions. First, the project is categorized as exempt from the requirement for a substantial development permit because it fits category B—normal maintenance in WAC 173-27- 040(2). 1 do not think the project qualifies for the exemption. The section states in part: .... Replacement of a structure ... may be authorized as repair where ... the replacement structure ... is comparable to the original structure ... including but not limited to its size, shape, configuration, location and external appearance and the replacement does not cause substantial adverse effects to shoreline resources or environment. The proposed maintenance includes: • Upsizing six 12" storm culverts to 18" • Adding 174 feet of 18" culvert alongside an existing 21" culvert • Adding a new storm vault ■ Upsizing a 21" pipe to the marine shoreline to 30" ■ Changing the discharge location from the top of the ravine directly to the marine shoreline several hundred feet to the north Since the size of the pipes is larger and the configuration and location are new, the proposal is not comparable to the original structure. Of even greater concern is the effect on the existing direct discharge to the marine shoreline. Erosion of the beach is evident with current stormwater runoff volumes. An increase in runoff volume will have an additional, substantial adverse impact on the shoreline robbing portions of the beach Natural Resources Department / 2952 S.E. Old OLUmpic Hwg. / Shelton, WA 98584 Fax (360) 426-397I / Phone (360) 426-978I of finer sediment particles and diminishing habitat value. For these reasons, the proposal does not qualify for the exemption because it is not normal maintenance. It qualifies as a re-design with a totally different external appearance. The second concern is the loss of water quality treatment when the discharge point is moved from the top of the bluff to a direct discharge on the marine shoreline. Water running through the ravine interacts with the substrate and a large gravel bar at the bottom of the hill. This action improves water quality by removing bacteria among other contaminants. The loss of such treatment threatens the health of a substantial geoduck population in the subtidal waters south of Dougall Point. If the project is to proceed as proposed, I request that additional mitigation be required to protect water quality and nearshore habitat. The easiest solution for water quality may be to incorporate some sort of treatment into the design of the stormwater vault. Once example is the Filterra System produced by Americast, but there may be other alternatives as well. To eliminate the adverse impact of the increased volume of stormwater runoff on the beach and nearshore zone, either flow volumes will have to be somehow metered at the top of the ravine, or improvements will be necessary to the existing energy dissipation structures at the outfall on the beach. If you have any questions, feel free to contact me at 432-3804 or ikonovsky(a)sauaxin.nsn.us. Best Regards, h onovsky Environmental Program Manager Page 1 of 1 Grace Miller - Harstene Pointe Maintenance Assoc. project TO BE KEPT IN THE From: Grace Miller To: hsellers@g-o.com P/ARCEL FI1 E Subject: Harstene Pointe Maintenance Assoc. project L- CC: jdougherty@g-o.com Sorry I was unable to get back with you until now. I did receive your response to the Squaxin Tribe's comments and thank you for all of the additional information which included photos, geotechnical report and letter. 1 forwarded the copy to the Tribe yesterday. It may not have gone out in the mail until today. I expect to speak with John Konovsky of the Tribe soon and will let you know what I hear as soon as possible. Thank you. about:blank 7/7/2009 Gray & 0sborrne, hic. CONSULTING ENGINEERS i'V'CE1VED JUL 01 2009 June 26, 2009 MCCD - PLANNING TO BE KEPT A 7 Ms. Grace Miller PA R C� r ` Mason County Department of Community Development f L.L P.O. Box 279 Shelton, Washington 98584 SUBJECT: SQUAXIN ISLAND TRIBE LETTER DATED JUNE 12, 2009 HARTSTENE POINTE MAINTENANCE ASSOCIATION, MASON COUNTY, WASHINGTON G&O#09452.00 Dear Ms. Miller: We received the letter you forwarded from the Squaxin Island Tribe dated June 12, 2009, and have prepared a few responses. On the first page, the project description is correct. However,the only portion within shoreline jurisdiction is the final 200 linear feet through an existing easement. This portion of the project would include part of the 18-inch culvert, a new storm vault, and a larger 30-inch pipe to the shoreline. The completed project would be little different from the existing facilities, except for a greater capacity. There would continue to be a single storm outfall, not two, as with the current proposed configuration. The existing upland driveway culverts along Pointes Drive East are damaged and need repair. These culverts would be replaced and upsized to convey additional stormwater. On page 2,there is a stated concern about the loss of water quality treatment. There is nothing about the current ravine discharge that is a positive water quality benefit. The problem with the ravine would not be apparent at this time of the year. To better explain the problem with the ravine, I have attached several items: • A photograph of the ravine during heavy rains, • A letter from a Hartstene Pointe resident, • A photograph of the existing footbridge, and • A geotechnical report prepared by Tubbs GeoScience. At some point during the past 10 years,the glacial till within the ravine has been breached due to storm runoff,the majority of which is from the County road. When the till was 701 Dexter Avenue N., Suite 200 Seattle, Washington 98109 (206) 284-0860 Fax (206) 283-3206 fir• Printed. recycled paper Ms. Grace Miller June 26, 2009 Page 2 breached, it exposed highly erodible sands and gravels. Please refer to page 4 of the Tubbs report. During heavy storm events, the ravine becomes a mining operation, with large quantities of sand and gravel sluicing down the steeper portions of the ravine into the flatter areas near the footbridge. Approximately 10 years ago, one could walk below the bridge, but as shown in the attached photograph, sands and gravels have accumulated to within 16 inches of the bottom of the bridge supports. Unfortunately, the problem does not stop at the footbridge. According to Mr. Anderson(letter attached), during winter storm events, an erosion plume forms in Case Inlet all the way from the lagoon to the north spit, a distance of nearly half a mile. This erosion plume flows directly into the geoduck bed identified as Dougall-015500. It is difficult to view the current ravine discharge as a positive water quality treatment when the stormwater passes through the ravine so rapidly and then carries large quantities of sediment into Case Inlet. If anything, the problem with the ravine erosion has worsened in the past 2 years. One large tree and several stumps have fallen into the ravine during this period. While it is impossible to predict the extent of future erosion, it does not appear that the banks have reached a point of stability and will continue to be undercut during heavy rainfall. Partly because of what has been observed during the past 2 years, it has been the goal of the Hartstene Pointe Maintenance Association to complete its drainage improvements this year. The goal of the proposed project is to mitigate the continuing erosion problem in the ravine. The existing stormwater discharge would be redirected along Pointes Drive East to an existing discharge point which would be upsized from 21 inches to 30 inches. The stormwater would first flow through approximately 952 linear feet of grass-lined ditch at a 4.5 percent slope before reaching the outfall culvert. We believe the grass-lined ditches will provide a superior water quality treatment system compared with the current ravine discharge. A photograph of the result we expect to achieve is attached. In addition,the stormwater vault provides a means of reducing the energy of the stormwater as it travels to the armored outfall. We have spoken with Margie Schiatto of the Washington State Department of Fish and Wildlife about the outfall to the beach, and she has visited the site. Based on our conversations with her, we propose to extend the pipe 18 inches beyond its current endpoint and then pile up rocks to the pipe invert. There is a substantial quantity of rocks in the immediate vicinity which would first be used and then supplemented with new two-man rock. A detail of what is proposed for energy dissipation is attached and will also be forwarded to the Washington State Department of Fish and Wildlife. e16 Pnnted on reeycled paper Ms. Grace Miller June 26, 2009 Page 3 Please call me at (206) 284-0860 or e-mail me at hsellers(cbg=o.com if you have any questions. Very truly yours, GRAY& OSBORNE,INC. 3C H =Sell , P.E. �' HES/hhj Encl. cc: Mr. Bob Rabourn, Manager, Hartstene Pointe Maintenance Association Gc> Printed on recycled paper TO BE KEPT IN THE 4 F i i RAVINE BELOW NANTUCKET DRIVE June 18,2009 To: Harry Sellers From: Jim Anderson RE: Cuttysark diversion project Harry, I had a conversation with Bob Rabourn about the status of the project and he recommended I send you a note describing the erosion created when the first major erosion event occurred in 2007. I live on 464 E. Chesapeake which is about half way from the Little Lagoon and the North Spit. Any time we have protracted bouts of heavy rain the erosion plume, which is chocolate in color and approximately 100 feet wide, is carried all the way to the end of the North Spit. Also at low tide (minus)it's easy to see how much the beach has changed due to the increased erosion. Last year 2008 we also had another event in Cuttysark ravine which created another large plume,however a bit smaller is size. Since the erosion has cut through the Glacial Till in the Cuttysark ravine and is now into sand and pebbles any significant rainfall will produce more of the same erosion to Case Inlet. Regards, 9irr Anderson wr _ M rywe R_ Y i T .w — +, �:. ,�} M� t.�,�'„l°*'t'•+'}'�,i,�4,`t�.��a���;��-w." � �ice'` c BOTTOM OF RAVINE AT FOOT BRIDGE TO BE KEPT IN THE o ° o a PARCEL FILE July 24,2008 REC'D J U L 2 8 2008 Hartstene Pointe Maintenance Association 202 Pointes Drive East Shelton, WA 98584 Summary Report Evaluation of Shoreline Conditions Hartstene Pointe Mason County, Washington File No. HARI-01 On March 10, 2008,together with a group of Hartstene Pointe board members and other residents, we performed a reconnaissance of the Hartstene Pointe shoreline and adjacent areas to observe geologic conditions and shoreline processes. This letter report provides a summary our observations, conclusions and recommendations, as they were discussed with the group during the reconnaissance. The geologic units underlying the Hartstene Point area include materials deposited during at least two glacial intervals and perhaps some of the intervening time. A lower,very compact glacial till unit(informally referred to here as the beach level till) exists near the base of the southeast and southwest bluffs. This glacial till was deposited during a glaciation that predates the most recent(Vashon) glaciation of this area. Still older fine-grained (silt and clay) deposits were observed in the bluff below the beach level till just north of Indian Cove. The beach level till is overlain by fine-grained soils and sandy soils which also appear to be pre-Vashon in age. These pre-Vashon units are overlain by glacial advance sand and gravel and by glacial till that was deposited during the Vashon glaciation, roughly 14,000 to 15,000 years ago, when glacial ice advanced southward,covering the Puget Sound area. At it's maximum,the ice was probably on the order of a 1,000 to 1,500 feet in thickness in the vicinity of Hartstene Island. The Vashon till and underlying sediments exposed along the bluffs within the Hartstene Pointe area are generally very dense as a result of being compacted by the ice. Some less dense silty and sandy soils locally overlie the Vashon till along the top of the bluffs,having been deposited during the retreat of the glacier. 7030 NE 134th Street Kirkland, Washington 98034 425-821-2015 www.tubbs,com Hartstene Point Maintenance Association July 24, 2008 Page 2 Shoreline processes including waves and currents,and mass-wasting processes such as landslides, have resulted in substantial shoreline erosion during post-glacial time. Sea level stabilized at approximately its present level some 7,000 years ago and since that time the shoreline has retreated several hundred feet. More shoreline retreat has occurred along the Case Inlet side of Hartstene Pointe than along the Pickering Passage side because the eastern shoreline is exposed to waves that are generated across a the longer open water fetch of Case Inlet to the southeast. This shoreline retreat has resulted in very steep bluffs,which occasionally fail by landsliding that deposits sediment on the beach face, from which it is subsequently removed by waves and currents. The most common types of landslides along the bluffs are debris slides and soilfalls. Debris slides occur on moderately to steeply sloping bluff segments, and mainly involve material that has been softened or loosened by weathering of the underlying geologic units. Soilfalls occur on nearly vertical bluffs and generally involve the glacially consolidated material. Some of the nearly vertical bluff faces in the Vashon till have joints (fractures) paralleling the bluff face, and these may control the location of failure surfaces. Where a failure surface extends all the way to the beach face,as was observed at one location along the beach,the slide material doesn't fall to the beach but instead moves as a slump block. The nearly vertical joints parallel to the bluff face have developed as a result of horizontal stress relief. When the Vashon till was consolidated beneath the glacial ice, it created both vertical and horizontal stresses within the soil. The vertical stress was relieved ,vhen the ice melted away,but the horizontal stresses were"locked-in"by the adjacent soil until shoreline erosion removed the soil along the side of the soil mass. The relief of the remaining horizontal stress toward the eroded bluff face produces joint planes paralleling the bluff face. The most conspicuous example of the effect of horizontal stress relief in Vashon till, and role of the near-vertical joints in the failure of a slump block, was observed along a high bluff segment facing Case Inlet adjacent to the Hinton residence. We understand that a rock bulkhead has been proposed there to protect the toe of the slide block from shoreline erosion,thereby decreasing the risk of additional failures within the intact till. We believe this is an appropriate response given the unusually high steep bluff at this location,the size of the slide block, and the proximity of the existing house to the top of the bluff. In general, areas where the base of the bluff consists of relatively erosion resistant material, such as the beach level till or hard fine-grained material, experience less rapid shoreline erosion, and areas where relatively erodible sandy material is exposed along the base of the bluff experience more rapid erosion. The long term rate of shoreline retreat along 7030 NE 134th Street Kirkland, Washington 98034 425-821-2015 www.tubbs.com Hartstene Point Maintenance Association July 24, 2008 Page 3 Puget Sound bluffs is typically in the range of 0.1 to 0.25 feet per year. However, shoreline retreat along the bluffs does not occur at a slow and steady rate but is episodic. Decades may go by with little or no or no observable changes,followed by one or more landslide events that result in several feet,or tens of feet,of bluff retreat. The amount of retreat along the top of the bluff that occurs during a single landslide event depends on the style and size of the landslide, but is typically in the range of about 3 to 10 feet. The primary, long-term cause of continued bluff retreat is the ongoing removal of material from the base of the bluffs by waves and currents. Some other factors affecting bluff retreat can be controlled and the rate of bluff retreat thereby decreased. Tree trunks and limbs that fall to the beach during landslides, and floating logs stranded during high tides,tend to protect the soils along base of the bluffs from waves and currents and slow the rate of erosion. This is particularly true in areas where landsliding occurs because the soils deposited at the base of the slope by landslide processes help hold the large organic debris in place, and are provided some protection from shoreline erosion by that debris. This natural process can be enhanced by using accumulated driftwood logs or fallen trees to armor the base of the bluff. The logs and other large debris can be anchored or cabled to help them stay in place, using whatever means experience or observations in nearby areas has shown to be effective. Such armoring would have the greatest effect where more erodible (e.g. sandy)materials exist along the base of the bluff,and would have least effect in area where erosion-resistant material, such as the beach level till, exist along the base of the bluff. Drainage near the top of the bluffs can also affect slope stability, and can be controlled in several ways. Runoff from roofs and other impervious surfaces within approximately 100 feet of the top of the bluffs can be routed to the storm drain system that exists within the upland portion of the development. Depressions in which water ponds during wet weather can be regraded or trenched to as to encourage runoff rather than infiltration. Such grading should not involve placing of large amounts(e.g.more than a few inches) of fill near the top of the bluff. If storinwater or other runoff must flow across the top of the bluff,it can be conveyed to the base of the slope via tightlines consisting of HDPE (High Density Polyethylene)pipe to beach level, with appropriate energy dissipation at the outfall. HDPE pipe is highly resistant to puncture and breakage, and is installed as a single continuous length of pipe that is not readily pulled apart by landsliding or other slope disturbance. Existing corrugated plastic pipes can be inspected for breakage or leakage by running water into the upper end of the pipe and observing the amount of discharge from its distal end, and any signs of leakage along the length of the pipe. Leaking pipes on steep 7030 NE 134th Street Kirkland, Washington 98034 425-821-2015 www.tubbs.com Hartstene Point Maintenance Association July 24, 2008 Page 4 slopes that might be eroded or destabilized by water exiting the pipe can be replaced on a priority basis. In general,it is preferable not to disturb soil and vegetation within approximately 15 feet of the top of the bluff. However, trees that have been undermined by erosion and that are at risk of failure, and which may represent a safety hazard to people either above or below, can be removed. This should be reviewed on a case by case basis by your arborist. If removed, such trees should be out low to the grotmd surface but the root structure allowed to remain intact. Replacement trees can be planted at a greater distance back from the slope. Where tree removal is anticipated, the replacement trees may be planted several years in advance so that their root systems are established before the roots of the removed tree have decayed. Other types of vegetation are also effective in preventing erosion, and should be considered as alternatives to replacement trees. Information regarding "Managing Vegetation on Coastal Slopes",and"Controlling Vegetation Using Vegetation"be found in two Department of Ecology publications by those names. Links to on-line versions of both publications can be found at geoinfo.com. One erosion problem that is not related to shoreline processes was observed within a deep ravine in the southeastern portion of the development. Surface water runoff from the upland drainage system,including runoff that enters the site from the County ditch system, has resulted in downcutting of the streambed and undermining of the adjacent ravine wall slopes. The downcutting is occurring within highly erodible glacial advance sand and gravel, immediately downstream from where the stream flows across the more erosion resistant Vashon till. Mitigation of the problem can involve rerouting some of the upland runoff to a different discharge point, and/or armoring the stream channel in the area where it transitions from the glacial till to the more erodible sand and gravel. This report has been prepared for Hartstene Pointe Maintenance Association and its representatives for use in planning and maintenance within the development. Within the limitations of scope, schedule and budget, our services have been accomplished in accordance with generally accepted geotechnical practices followed in this area at the time the report was prepared. No warranty, expressed or implied, should be understood. 7030 NE 134th Street Kirkland, Washington 98034 425-821-2015 www.tubbs.com Hartstene Point Maintenance Association July 24,2008 Page 5 We appreciate the opportunity to be of service to you. Please contact us if you have any questions regarding this report. Yours very truly, Tubbs Geosciences Cl�Wash.i h9�0 � 7 Engineering Geo4131 �. �Oo 756 ed Ge°�o Donald W. Tubbs,Ph.D. Donald W. Tubbs Engineering Geologist Document ID:HARIOIRI I I 7030 NE 134th Street Kirkland, Washington 98034 425-821-2015 www.tubbs.com y f� y.ae S yy r POINTES DRIVE E: GRASS LINED DITCH Y Q W LY_ m W d � Q 0 H U) X W NEW 30" CMP ROCKERY W/ 1 -- ! AND 2 MAN r - - - - - - - -- - ROCKS I1 OUTFALL PLAN 3 SCALE: 1"=5' 1 NOTES: 1. ROCKERY: 1 MAN 50-200 LBS±, 12"-18" DIA. 2 MAN 200-700 LBS±, 18"-28" DIA. 2. USE EXISTING ROCKS AS APPROPRIATE. 10' ROCKERY W/ 1 AND 2 MAN - - - ROCKS NEW 30" CMP in L6 OUTFALL SECTION o SCALE: 1"=5' -