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01-100602 CITY OF •-- E O % b CITY HALL 33530 1st Way South (253) 661-4000 PO Box 9718 Federal Way, WA 98063-9718 Mr. John Stucky March 14, 2001 DKA Architects 2107 Elliott Avenue, Suite 305 �� E Seattle, WA 98121 Re: File No: #01-100602-000-00-PC; Preappiication Conference Summary Agodoa Residence; 518 South 288th Place, Federal Way, WA Dear Mr. Stucky: Thank you for meeting with the City's Community Development Review Committee (CDRC) regarding your proposed project. The committee includes representatives from the Lakehaven Utility District, Federal Way Fire Department, and staff from the City's Planning and Building Divisions and Public Works Department. This letter summarizes our pre-application conference on March 8, 2001, at which time members of the CDRC discussed development requirements as they apply to the proposal to construct a three-story single family home at 518 South 288th Place. Where appropriate, pertinent ordinance sections are noted. The items listed below do not include all regulations applicable to the subject proposal. In preparing your application, all pertinent portions of the City's land use code must be consulted. PLANNING DIVISION — (Jane Gamble, 253-661-4120) 1. Zoning: The subject property is zoned Single Family Residential (RS15). Pursuant to Federal Way City Code(FWCC) Section 22-631 (enclosed), the following development regulations apply. • Minimum Lot Size: The minimum lot size in this zone is 15,000 square feet. The lot at 518th South 288th Place, parcel number 515293 0230, measures 22,500 square feet and as such, satisfies this requirement. • Setback Requirements: The required front setback is 20 feet; side and back setbacks are 5 feet. As proposed, the site plan for the residence meets these setback requirements. • Maximum Lot Coverage: The maximum lot coverage in an RS 15.0 zone is 50 percent. The project, as proposed, does not exceed this threshold. Mr. John Stucky Page 2 March 14, 2001 • Maximum Height: The maximum height of the structure cannot exceed 30 feet above average building elevation. Pursuant to FWCC Section 22-1, Definitions, the'average building elevation' means a reference datum on the surface topography of a subject property from which building height is measured. The reference datum shall be a point no higher than five feet above the west elevation taken at any exterior wall of the structure, either prioo Averment activity or at finished grade, whichever is lower. As proposed, your project measures 32 feet in height from the 1st floor to the roofline. In that the reference datum is measured five feet above the proposed lowest elevation of 160 feet, the height appears to meet code requirements. 2. Geologically Hazardous Areas Development: Pursuant to the FWCC, development activities and land surface modifications on or within 25 feet of a geologically hazardous area are regulated by FWCC Division 4, Geologically Hazardous Areas Development(enclosed). The FWCC defines a Geologically Hazardous Area to include the following: 1) Erosion Hazard Areas; 2) Landslide Hazard Areas; 3) Seismic Hazard Areas; and 4) Steep Slope Hazard Areas. Your project site appears to meet the definition of two of these Geologically Hazardous Areas. According to the City of Federal Way Geographic Information System's analysis of sensitive areas, your proposed site is within an Erosion Hazard Area. The FWCC defines an Erosion Hazard Area as those areas having severe to very severe erosion hazards due to natural agents such as wind, rain, splash, frost action, or stream flow. Also, according to the site plan you have submitted, it appears that the subject site is , within a Steep Slope Hazard Area. Pursuant to FWCC Section 22-1 (enclosed), a steep slope hazard area is defined as having a slope of 40 percent or greater, with a vertical relief of 10 or more feet and a vertical rise of 10 feet or more for every 25 feet of horizontal distance. Development activity occurring in any or all of the environmentally sensitive areas defined by code is subject to special regulations pursuant to FWCC Division 4, Geologically Hazardous Areas Development. As part of preapplication submittal information, you have provided a geotechnical evaluation of the site, prepared by Geospectrum Consultants, Inc., of Issaquah, Washington. In this report, there is reference to one to three feet of loose/soft fill soils in the upper east side of the site. The geotechnical report appears to conclude that these soils were artificially added to the site. In addition, a drainage document of the Marine View. subdivision from 1974 appears to indicate that the grade on this particular portion of the site was originally different from current elevations. The geotechnical evidence, in conjunction with the 1974 drainage plan, appears to support the conclusion that the easterly steep slope that is within 25 feet of the proposed development may have been artificially created. Please be advised that the City does not staff qualified geotechnical professionals who can make the required determination on this issue. City policy provides for a substantive analysis of submitted geotechnical reports, conducted by City consultants, as part of the formal application review process. Pursuant to FWCC Section 22-1286(d), the City will Doc.I.D.13643 . Mr. John Stucky Page 3 March 14, 2001 require the services of a qualified professional engineer to review the soils report and other relevant information provided in the geotechnical report. The fee for this review is the responsibility of the applicant. A scope of work and pass thru account will be established when the applicant is prepared to proceed with the process. For your information, regardless of the present uncertainty surrounding the geological nature of this slope, the requirements of Geologically Hazardous Areas Development regulations are necessitated by the fact that this project lies within an Erosion Hazard Area. Furthermore, the following code-based requirements may also be applied: . 1) The City may require that a qualified professional engineer be present on site during all land surface modification activities. 2) The City may require that trees, shrubs, and groundcover be retained except where necessary for approved development activities. 3) Prior to issuance of any building permit, the applicant may be required to enter into an agreement with the City, in a form acceptable to the City Attorney, releasing and indemnifying the City from and for any damage or liability resulting from any development activity on the subject property that is related to the physical condition of the steep slope. This agreement, if required, shall be recorded in the county, at the applicant's expense, and shall run with the property. 3. State Environmental Policy Act(SEPA): Pursuant to FWCC Section 18-143, the developments that are exempt from SEPA requirements under the Washington Administrative Code (WAC) 197-11-800 are nonetheless subject to SEPA review when the project is located in an environmentally sensitive area. The Revised Code of Washington (RCW) and WAC include geologically hazardous areas in the designation of environmentally sensitive areas. As such, SEPA review is required. An environmental checklist must be submitted and reviewed prior to the City issuing an environmental threshold determination. All property owners and occupants within 300 feet of the site must be notified of that decision. The notification includes a 14-day comment and 14-day appeal period. SEPA review must be concluded before building permits can be issued for the project. SEPA noticing provisions require the applicant to submit one set of mailing envelopes addressed to all owners of property within 300 feet of the property boundaries. Additionally, one set of occupant envelopes addressed to all occupants within 300 feet of the property boundaries must be provided. The occupant mailing is intended to provide SEPA notice to non-owner occupied units within 300 feet of the subject property. Please clearly label and identify the two sets of mailing envelopes. All mailing envelopes must be stamped and addressed (include the City's return address: PO Box 9718, Federal Way, Washington, 98063-9718). Along with the mailing envelopes, lists of addresses clearly identified as owners or occupants must be provided along with an assessor's map showing the 300-foot radius from all property boundaries. A handout for obtaining mailing labels is enclosed. Doc.I.D.13643 ro • Mr. John Stucky Page 4 March 14, 2001 4. Review Process: Although this project requires SEPA review, it is not subject to any other Land Use Process. 5. Fees: The fee for SEPA review is $1,143.00, and includes Fire Department and Public Works review. The $321.00 preapplication review will be credited toward this SEPA fee. Additional fees are associated with other City review and district regulations and permits. Building permits must be obtained before any work commences. PUBLIC WORKS DEVELOPMENT SERVICES DIVISION—Jim Femling, 253-661-4196 Please refer to the enclosed March 13, 2001, memorandum that covers land use and building permit related issues. BUILDING DIVISION—Joan Hermle, 253-661-4152 Please refer to the enclosed March 8, 2001, memorandum from Mary Kate Gaviglio. LAKEHAVEN UTILITY DISTRICT— Mary Young, 253-946-5400 Please refer to the enclosed March 8, 2001, memorandum from Mary Young. FEDERAL WAY FIRE DEPARTMENT—Greg Brozek, 253-946-7242 Please refer to the enclosed March 8, 2001, memorandum from Greg Brozek. The sign-up sheet from the meeting is enclosed. Thank you for participating in the preapplication process. As you know, this is a preliminary review only and does not take the place of a full review of the formal application. If you have any questions, please contact me at 253-661-4120, or other staff persons as appropriate. I look forward to working with you to make this a successful project. Sincerely, 7i1itht1a4b( Jane Gamble Associate Planner enc: FWCC Section 22-631, Single Family Residential FWCC Section 18-143, Environmental Protection FWCC Section 22-1, Definitions FWCC Division 4, Geologically Hazardous Areas SEPA Checklist Public Works Development Services Division Memorandum Building Division Memorandum Lakehaven Utility District Memorandum Federal Way Fire Department Memorandum Doc.I.D.13643 GEOSPE TRUM CONSuLTANTS, INC. veotec/�r�ica/ E g rfr-)g ar c1 Eartf-i Sc/ races August 3, 2000 Lawrence and Shirley Agodoa 13217 Glenhill Road Silver Spring, MD 20904 SUBJECT: GEOTECHNICAL EVALUATION Proposed Residence Site Lot 23, Marine Hills #17 Federal Way, Washington Project No. 00-118-01 Dear Lawrence and Shirley, This report presents the results of our geotechnical evaluation of your proposed residence site and the adjacent slopes. Our work was performed in accordance with the scope and conditions of our proposal dated April 17, 2000. The purpose of our work was to evaluate general conditions of the slopes adjacent to the site and provide our opinions regarding slope stability and recommendations for building setbacks from the top of the adjacent slopes as well as general development recommendations. Donald King Architects initially provided us a preliminary site development plan and a partial topographic map which were used as references for our site explorations. Subsequently we were provided with an expanded site topographic map dated 7-26-00 for use in our slope stability analyses. We understand that you propose to construct a wood frame residence on the site. At this time we understand that the structure will have a daylight basement level which will include a two-car garage with slab-on-grade floor. Development will also include a circular front driveway and access to the basement level garage. For the purpose of our evaluation we have assumed that maximum bearing wall loads will be about 3 kips/ft or less. If actual structural loads exceed this value by more than 1/3 our office should be notified. P.O. Box 276, Issaquah, WA 98027-0276 • Phone: (425) 391-4228 Fax: (425) 391-4228 Agodoa August 3, 2000 SCOPE OF WORK Our geotechnical reconnaissance included site observations, engineering evaluations and the preparation of this report. The scope of work included the following specific tasks: o Reviewed published geologic mapping for the site vicinity. o Performed subsurface explorations of the upper site area. Five borings were drilled to depths ranging from 4 to 16.5 feet within the proposed development area and at the top of the steep slope. o Performed laboratory testing of selected soils samples from our explorations. o Performed a site reconnaissance to observe the surface conditions on the site and on the slopes below the site. o Performed engineering evaluations and slope stability analyses of the observed site conditions to develop geotechnical recommendations for structure-slope-setbacks and general site development. o Prepared this geotechnical report summarizing our findings and recommendations for site development. OBSERVED SITE CONDITIONS The property is located along the top of the coastal bluff slope as approximately shown on Figure 1. The building site is located within the moderately sloped southern half of the property which is bordered along the north side by the very steep coastal bluff slope. Our site explorations and reconnaissance were made on 5/24/00. The property was undeveloped at the time of our field work. A topographic map of the site area is included in the site plan of Figure 2. The upper site topography slopes gently to moderately to the east-southeast and is bordered along the northwest side by a steep northwest facing slope which is in turn bordered along its north side by very steep bluff slopes. The topography of Figure 2 and our observations and measurements of the north bluff slope indicate that the upper portion of the slope inclines at angles of about 25 to 35 degrees for vertical heights of 10 to 30 feet. The very steep slope area below the upper slope extends down for a vertical height of 60+ feet at the east property boundary with slope angles of about 45 to 50+ degrees and then flattens somewhat to angles ranging from about 35 to 40 degrees in the lower 30+ vertical feet of the slope. Project No. 00-118-01 Page 2 • Agodoa August 3, 2000 Based on the topography of Figure 1 the total height of the bluff is indicated to range from about 80 to 100+ feet. We did not observe any evidence of instability such as ground cracks or anomalous surface topography within the moderately sloped building site area of the property however we observed evidence of slope failures on the very steep north bluff slope. We observed two existing landslide areas on the very steep bluff slope which included a large slide near the top of the slope at the east property boundary and a smaller slide near the toe of the slope below the northwest property corner (see Figure 2). An existing gabion wall (wire cage rock wall) was apparently constructed in the past to help stabilize the lower slide area. Both the upper moderately sloped building area and the adjacent bluff slope were generally well vegetated. The building area was covered with grass in the southern 2/3 and heavy blackberry growth in the northern 1/3. The bluff slope vegetation included blackberries ferns, salmon berries, alder and maple trees and occasional fir trees. Subsoils Subsoil conditions were observed in our subsurface borings and in the slide scars and shallow test pits excavated in the very steep bluff slope. Five subsurface borings were drilled at the approximate locations shown on Figure 2 to depths ranging from 4 feet to 16.5 feet. Logs of the borings are presented in Appendix A. Subsoils encountered at the boring locations in the upper site area generally consisted' of alternating layers of silt, sandy silt, silty sand and sand. Borings 2 and 3 drilled cry \ along the upper east side of the site encountered an estimated 1 to 3 feet of loose/soft fill soils. Generally the weathered natural soils (at the surface or below fill soils) were 1r>✓ ,n also loose/soft to depths of about 2 to 3 feet. The less weathered natural soils were tO found to be generally stiff to very stiff and dense to very dense below depths of about 2 • k. to 3 feet below the natural ground surface. 'V`" Soils observed in Boring 1 at the top of the bluff combined with observations of our shallow test pits on the bluff slope and observations of the upper landslide scar indicate that the soils in the upper half of the bluff slope consist of layers of very dense silty sand with gravel and sand with gravel. In addition a layer of hard silt was encountered to a depth of 8 feet in Boring 1 and another silt layer was observed in a slope test pit at about elevation 105. Glacial till-like silty fine soils were observed in our shallow test pits in the lower half of the slope and were also exposed in the lower slide scarp. Ground Water No seeps or springs were observed in the building site area or on the bluff slopes and no free ground water was observed in any of our borings. Soil samples obtained from Project No. 00-118-01 Page 3 . ' 1 Agodoa August 3, 2000 the exploratory borings were generally field classified as moist although soils below about 6 feet in Boring 2 were classified as very moist to wet. Measured moisture contents ranged from about 7 percent (of dry weight) to 37+ percent. Moisture contents were generally higher in the silt and sandy silt soils (24 to 37+ percent) and lower in the sand and silty sand soils (7 to 17+ percent). SITE EVALUATIONS General Based on the results of our field observations combined with review of the referenced information, it is our opinion that the site can be developed provided that adequate setbacks from the adjacent slopes are maintained and site drainage is controlled. Review of published geologic mapping (see Figure 1) indicates that the site lies near a contact between older Salmon Springs drift (Qss) at higher elevations and sandy glaciolacustrine deposits (Qis) and undifferentiated Vashon glacial drift deposits (Qg) on the lower elevations to the west and east respectively. The Vashon glaciation, the last glacial advance into the Puget Sound area, occurred approximately 13,000 to 16,000 years ago. The Salmon Springs drift were deposited during glacial periods pre- dating the Vashon glaciation The Salmon Springs drift are indicated to be chiefly sand and gravel deposits with local beds of very fine sand, silt and clay. The glaciolacustrine soils in the site area are indicated to be chiefly sand soils (Qis) from the Vashon glaciation. The undifferentiated Vashon drift could range from glacial till (a very dense/hard soil mixture that can include clay, silt, sand and gravel of varying proportions) to advance outwash deposits (typically very dense sand and gravel soils). The soils observed on the site are considered generally consistent with the geologic mapping. Stability Hazard Assessment The geologic map of Figure 1 does not show any large mapped landslides in the site vicinity, however we observed two significant landslide areas in the bluff slope below the site (see Figure 2). The larger slide scar which is centered along the eastern property line at the northeast corner of the property appears to have been a shallow to moderately deep slide on the very steep bluff slope and has deposited slide debris over the lower portions of the slope. The smaller slide scarp extends roughly 20+ feet above the parking lot at the toe of the bluff and appears to be a relatively shallow slide involving the outer few feet of the very steep slope surface. The existing gabion wall (wire cage rock wall) at the toe of the bluff slope was apparently constructed to help stabilize the lower slide area. Project No. 00-118-01 Page 4 Agodoa August 3, 2000 Although our observations indicate that the proposed building site area is currently stable with regard to deep-seated static failure it is our opinion that the risk of future failures of the existing very steep bluff slope is very high. There is also high risk of re- activation or expansion of the existing landslides observed on the bluff slope. Expansion of the larger upper slide could affect the upper portion of the bluff slope and ultimately into the area above the top of slope line indicated by the surveyor. However re-activation or moderate expansion of the smaller toe of slope landslide is not expected to have a significant impact on the building site. The nature of future failures on the steep slopes is expected to be predominantly moderate to shallow "skin" failures due to the generally granular nature of the slope materials. Slope failures are most likely to occur during very heavy rainfall periods and/or during strong ground shaking from moderate to large earthquake events. Deeper failures may occur during strong earthquake shaking depending on the site acceleration levels. Localized shallow slumping and sloughing on the steep bluff slopes is not expected to have significant impact on the proposed residence provided it is adequately set back from the top of slopes. However as with all hillside development you, the owner, must be aware of and accept the risk that future slope failures may occur and may result in damage to your property and/or neighboring property. To help maintain stability, disturbance of the existing slopes should be minimized and site drainage controlled. • The risk of structure damage resulting from a slope failure varies with the distance from the slope, the slope height and its steepness as well as other factors. In general to minimize risk, structures should be set back from the top of the adjacent steep slopes as far as possible within the constraints of the development plans. We performed stability analyses of the existing bluff slope to determine appropriate setbacks from the bluff slope. Slope geometry used in our analyses was based on the topography of Figure 2 combined with our own observations and measurements of the bluff slope. Subsoil conditions were based on the results of our subsurface explorations combined with our observations of soils exposed in the landslide scars and observations in our shallow slope test pits. Our stability analyses considered both static stability and the potential effects on site stability due to seismic ground motions. In accordance with the 1997 UBC a ground acceleration level with an average return period of about 475 years was considered for seismic loading conditions. A ground acceleration level with an average return period of about 475 years, based on the historic record, was considered in our determination of our recommended BSBL. This risk level was calculated to correspond to about 0.24g peak ground acceleration (see Seismic Considerations). Recommended minimum Building Setback Lines (BSBL) are intended to place the proposed development at a distance from the slope where the risk is at a reasonable level generally considered acceptable by the engineering profession. The Project No. 00-118-01 Page 5 • Agodoa August 3, 2000 determination of our recommended minimum Building Setback Lines (BSBL) was based on a minimum calculated static stability safety factor of 1.5 and seismic lateral slope deformations of % inch or less under the UBC seismic design criteria. Due to factors including the large landslide and resulting over-steep slope along the east property line and the higher elevations, the results of our analyses indicate that the recommended BSBL at the east property boundary is 70 feet from the top of slope indicated on the topographic map however the BSBL distance diminishes westward to a minimum of 25 feet at the west property boundary as shown in Figure 2. Further discussion of our recommended minimum Building Setback Line (BSBL) for this site is presented in the RECOMMENDATIONS section of this report. Erosion Hazard Assessment Currently the property is generally well vegetated. However based on our observations the subsoils are generally silt-sand-gravel mixtures of varying proportions and are considered to have a high erosion potential when exposed in unvegetated or disturbed slope areas. Disturbed or unvegetated areas should be planted with ground cover to retard surface erosion and ravelling. Due to the very steep slope gradients, it may be necessary to use special hydro-seeding techniques to establish vegetation on the bluff slope areas. We have provided additional recommendations for erosion control during and after construction our recommendations section which follows. Seismic Considerations The Puget Sound region is a seismically active area. About 16+ moderate to large earthquakes (M5 to M7+) have occurred in the Puget Sound and northwestern Cascades region since 1872 (128 years). The larger recorded seismic events have included the magnitude 7+ north Cascades earthquake of 1872, the magnitude 7.3 Vancouver Island earthquake of 1946, the magnitude 7.1 Olympia earthquake of 1949, the magnitude 8.1 Queen Charlotte Island earthquake of 1949 and the magnitude 6.5 Seattle earthquake of 1965. In addition to Puget Sound seismic sources, a great earthquake event (M8 to M9+) has been postulated for the Cascadia Subduction Zone (CSZ) along the northwest Pacific coast of Oregon, Washington and Canada. The current risk of a future CSZ event is not known at this time. Published reports have indicated recurrence intervals for a CSZ event to range from as little as 100-200 years to as long as 1000+ years and the time of the last event is reported to have been about 300 years ago. Based on a recently published study prepared by the USGS, the site lies about 14 miles south of the southernmost surface trace of the Seattle fault and only about 7 miles east of the postulated trace of a newly discovered north-south trending fault Project No. 00-118-01 Page 6 Agodoa August 3, 2000 which bisects Vashon Island. The Seattle fault has been documented to have moved at its west end (Bainbridge Island) about 1000 to 1100 years ago but evidence of movement at the east end is not well documented. Some experts feel that the recurrence interval between large events on the Seattle Fault may be on the order of several thousands of years but our calculations indicate it may be on the order of 1200 to 1400 years. The activity of the newly discovered north-south fault is considered to be on the same order as the Seattle fault because it offsets the Seattle fault where the two intersect north of Vashon. The 1997 UBC requires consideration of a ground acceleration level with an average return period of about 475 years for seismic design. Based on an analysis of historic seismic events within the Puget Sound/North Cascades area an average 475-year recurrence ground acceleration was calculated to be about 0.24g peak for the general Puget Sound region. RECOMMENDATIONS Recommended Building Setback Lines (BSBL) The risk of structure damage resulting from a slope failure varies with the distance from the slope, the slope height and its steepness as well as other factors. In general to minimize risk, structures should be set back from the top of the adjacent steep slopes as far as possible within the constraints of the development plans. As a minimum we recommend that the proposed structure be located behind the Building Setback Line (BSBL) as shown on Figure 2. We recommend that a minimum setback of 70 horizontal feet be provided between the structure and the top of the bluff slope at the east property boundary. The recommended building setback diminishes westward to a minimum of 25 feet at the west property boundary (see Figure 2). Slope setbacks should be verified by field measurements during construction. The recommended BSBL includes the combined buffer and setback. In our opinion structures founded on dense/hard natural soils behind the recommended BSBL will be stable and normal construction practice should not affect the adjacent slopes. Spread Footing Foundations Conventional spread footings founded on undisturbed dense/hard natural soils with slope setbacks equal or greater than the recommended minimums should provide good support for the proposed structures. Where fill soils or loose/medium dense soils are encountered, the footings should be deepened as required to penetrate through those soils to bear on undisturbed dense natural soils. Project No. 00-118-01 Page 7 • Agodoa August 3, 2000 Continuous footings should be at least 18 inches wide and square footings should be at least 24 inches wide. All footings should be founded at least 18 inches below the lowest adjacent final grade. Footing design may be based on a maximum allowable bearing pressure of 2000 psf for both continuous and square footings. Settlement of foundations supported on undisturbed dense natural or hard natural soils is expected to be within tolerable limits for wood-frame construction. The estimated settlement of a 1.5 foot wide continuous footing carrying a load of up to 3 kips per foot is on the order of 1/4 to 1/2 inch. Maximum differential settlement within the proposed structure is expected to be on the order of 1/4 inch. Settlements are expected to occur primarily during construction. Resistance to lateral loads can be assumed to be provided by friction acting at the base of foundations and by passive earth pressure. A coefficient of friction of 0.35 may be assumed with the dead load forces in contact with on-site soils. An allowable static passive earth pressure of 250 psf per foot of depth may be used for the sides of footings poured against undisturbed dense/stiff natural soils or properly compacted structural fill. The vertical and lateral bearing values indicated above are for the total dead load plus frequently applied live loads. For short duration dynamic loading caused by seismic or wind forces, the vertical bearing values may be increased by 50 percent and allowable lateral passive pressures may be increased by 33 percent. Retaining Walls Cantilevered retaining walls as referred to in this report are walls which yield or move outward during and after backfilling. Actual wall movements will depend on the wall design and method of backfilling and can range from 0.1% to 0.3% of the wall height. Design pressures for cantilevered walls given below assume that the top of the wall will deflect at least 0.2% of the wall height. Static design of permanent cantilevered retaining walls which support a horizontal surface of properly compacted clean free-draining granular material may be based on an equivalent fluid density of 35 pcf. Walls supporting a sloping backfill up to a gradient of 2:1 (horizontal:vertical) should be designed based on an equivalent fluid pressure of 55 pcf. These pressures assume that there is no water pressure with the wall backfill. An additional uniform lateral pressure due to backfill surcharge should be computed using a coefficient of 0.25 times the uniform vertical surcharge load. Static design of walls structurally braced against movement should be based on an equivalent fluid density of 60 pcf for horizontal backfill. Braced walls supporting a sloping backfill up to a gradient of 2:1 (horizontal:vertical) should be designed based on an equivalent fluid pressure of 100 pcf. These pressures assume that the wall supports properly compacted free-draining granular material and that there is no water Project No. 00-118-01 Page 8 Agodoa August 3, 2000 pressure behind the wall. Uniform lateral pressure due to a uniform vertical surcharge behind a braced wall should be computed using a coefficient of 0.45 times the uniform vertical surcharge load. Seismic design of retaining walls should include a dynamic soil loading based on a 0.24g 475-year recurrence ground motion level. Dynamic soil pressure should be assumed to have an inverted triangular distribution. The dynamic soil pressure at the top of the wall should be at least 20H (psf) where H is the height of the wall above the footing base. The dynamic soil pressure should diminish linearly to zero at the base of the wall. Combined static plus dynamic soil pressure should be used for seismic design of the walls. Care should be exercised in compacting backfill against retaining walls. Heavy equipment should not approach retaining walls close enough to intrude within a 1:1 line drawn upward from the bottom of the wall. Backfill close to walls should be placed and compacted with hand-operated equipment. Recommendations for placement and compaction of structural fill are presented under "Site Grading". Design wall pressures given above assume no water pressure behind the walls. We recommend that a drainage zone be provided behind all retaining walls and a adequate drain system be provided at the base of all retaining walls. As a minimum, the drainage zone should extend the full height of the wall with a horizontal width equal to at least 2 feet. Backfill within the drainage zone should be a clean sand/gravel mixture with less than 5 percent fines based on the sand fraction. A membrane of Mirafi 140 filter fabric or equivalent should be provided between the drainage zone material and onsite silty soil backfill. Wall drains should consist of a four-inch diameter perforated PVC drain pipe placed in at least one cubic foot of drain gravel per lineal foot along the base of the wall. Drain gravel should be washed material with particle sizes in the range of 3/4 to 1-1/2 inches. The drainage zone backfill should be capped with paving or 12 inches of silty soils to reduce surface water infiltration. Conventional spread footing foundations founded on undisturbed dense natural soils may be used for support of retaining walls. Design of wall foundations should be in accordance with the recommendations presented under "Spread Footing Foundations" Site Grading Site grading is expected to consist primarily of excavation for foundations and fill placement to prepare slab and pavement subgrades. Stripping depth required in areas with no existing fill is expected to be about 1 to 3 feet. Onsite natural sand soils (excluding topsoil) are considered suitable for structural fill provided that the moisture content can be adequately controlled. In our experience sands with high silt content can be very difficult to compact under high moisture conditions. Where possible onsite silty sand soils should be used in dry, low humidity weather. Wet weather grading may require the use of imported cleaner sand/gravel soils. Project No. 00-118-01 Page 9 r Agodoa August 3, 2000 Recommendations for site preparation, temporary excavations, structural fill, fill slopes, cut slopes and utility trench backfill are presented below. Site Preparation: Existing vegetation, debris, fill and soft or loose soils should be stripped from the areas that are to be graded. During rough grading, excess soils may be stockpiled for later use. Soils containing more than 1% by weight of organics may be used in planter areas, but should not be used for fill beneath building or pavement areas. Stumps, debris and trash, plus rocks and rubble over 6 inches in size, should be removed from the grading areas. Subsoil conditions on the site may vary from those encountered in the test pits. Therefore, the soils engineer should observe the prepared areas prior to placement of any new fills. Temporary Excavations: Sloped temporary construction excavations may be used where planned excavation limits will not undermine structures or interfere with other construction. Where there is not enough room for sloped excavations, shoring should be provided. Sloped temporary excavations may be made vertically to depths less than 4 feet provided that no existing structure is within a 1:1 (horizontal:vertical) projection up from the toe of the cut. Deeper temporary excavations should be made at slope gradients no steeper than 1.25:1 (horizontal:vertical) in the upper loose/soft soils but gradients may be increased to 0.75:1 (horizontal:vertical) in very dense/hard natural soils. If ground water seepage is encountered, flatter slopes may be required for adequate stability. It should be noted that the contractor is responsible for safety and maintenance of construction slopes. Soils exposed in cut slopes should be kept moist, but not saturated, to retard ravelling and sloughing. Surface drainage should be directed away from the top edge of cut slopes. Surcharge loads should not be allowed within 5 feet of the top of cut slopes. Structural Fill: Excavated onsite sand soils are considered suitable for general structural fill provided that moisture conditions can be adequately controlled. Organics and any existing fill and loose/soft soils and debris should be removed from structural fill areas prior to placing structural fill or backfill. Structural fill should be placed in horizontal layers not exceeding 8 inches in loose thickness and compacted to at least 90% of the maximum dry density as determined by the ASTM D1157-91 test method. Imported material for fill should be clean, well-graded sand and gravel materials free of organic debris and deleterious material with less than 20 percent fines based on the sand fraction. Subqrade Preparation: Existing fill, topsoil and soft, loose or disturbed soils should be excavated to expose dense/stiff natural soils in slab and pavement subgrade areas and Project No. 00-118-01 Page 10 • Agodoa August 3, 2000 structural fill placed as required to final subgrade. Structural fill should consist of approved onsite sand soils or imported well-graded sand and gravel materials free of organic debris and other deleterious material. Subgrade structural fill should have a maximum particle size of 3 inches. Subgrade structural fill should be placed in horizontal lifts not exceeding 8 inches in loose thickness and compacted to at least 90% of the maximum dry density as determined by the ASTM D1557-91 test method. Risk of slab cracking can be reduced by placing 2-way reinforcement steel. If a floor covering is used, the slab should be underlain by a polyethylene vapor barrier of at least 6 mil thickness. If a vapor barrier is used it should be covered with 2 inches of clean sand to reduce punctures and aid in concrete curing. Permanent Slope Design: All permanent slopes should be made no steeper than 2:1 (horizontal:vertical). All vegetation, debris, slopewash and weathered soils should be removed from the proposed fill slope areas prior to fill placement (see "Site Preparation"). All fill slopes should be keyed and benched into undisturbed dense/stiff soils. Utility Trenches: Buried utility conduits should be bedded and backfilled around the conduit in accordance with the project specifications. Where conduit crosses pavement subgrade areas the backfill above the pipe should be placed and compacted in accordance with the recommendations for structural fill. Rockery Construction Rockeries should be considered primarily as facing for stable cut slopes in competent natural soils that will require periodic inspection and repair. They should be located so that they can be reached by a contractor if repairs are necessary. The rockery keyway should be excavated to expose dense/hard natural soils. The competency of the foundation subgrade and stability of the exposed slope face should be verified by the geotechnical engineer prior to placing rock. Rocks placed in the lower half of an 8 foot rockery should be 3000 to 4000 lb. rock, or larger. Rocks placed above this level may gradually decrease in size with increasing height but should be no smaller than 750 lbs. The long dimension of the rocks should be oriented into the slope for maximum stability. Where rockeries support fill soils, we recommend that the minimum rock dimension (into the face) be at least 2 feet or 1/2 the rockery height above the level of the base of that rock whichever is larger. This would require 2 to 3 foot long (2000 to 4000 lb.) rock at the base for support of a 4 to 5 foot fill height. We recommend that rockeries not be used for support of fill greater than 5 feet. Project No. 00-118-01 Page 11 Agodoa August 3, 2000 Rocks should be placed to avoid continuous joint planes in the vertical or lateral directions. Each rock should bear on two or more rocks below it, with good flat-to-flat contact. The rockery face should be battered into the slope at a gradient of 1 h:5v or flatter. A minimum 18-inch wide layer of well graded gravel drain material should be provided for the full height behind the rockery with a 4" minimum perforated drain pipe at the base. Drain pipes should consist of 4-inch minimum diameter, perforated or slotted ridged plastic PVC pipe laid with a positive gradient to a controlled, non-erosive discharge into the storm drain system. Drain pipes should be placed below the lowest rock and should be bedded on and surrounded by the gravel drain material. Special care should be exercised in compacting fill behind rockeries. Heavy equipment should be kept beyond a 1.5:1 (h:v) line drawn upward from the bottom of the rockery. Backfill close to rockeries should be placed and compacted with hand-operated equipment as the rockery is constructed. Recommendations for placement and compaction of structural fill are presented under "Structural Fill" . Drainage Control Surface drainage from the upper site areas should be controlled and discharged from the development area in a non-erosive manner. Adequate positive drainage should be provided away from the structure and on the site in general to prevent water from ponding and to reduce percolation of water into subsoils. Positive drainage should be provided away from the north bluff slope as much as possible to minimize water flow over the slope and help reduce stability and erosion hazard. A desirable slope for surface drainage is 2% in landscaped areas and 1% in paved areas. Roof drains and surface area drains should be tightlined to the storm drain system in the street. A permanent perimeter drain, independent of the roof drain system, should be placed adjacent to the base of the continuous exterior foundations and should consist of a four-inch diameter perforated PVC drain pipe in at least one cubic foot of a well graded sand and gravel filter material per lineal foot. Erosion Control Onsite materials are expected to be highly erodible when exposed in slope areas. No grading or soil disturbance should occur within a buffer equal to 50 feet or a distance equal to the recommended BSBL (whichever is less) from the top of the slope. No excavated material should be placed on the slopes or within the slope buffer area. Soil stockpiles should be covered during heavy rainfall and siltation fences or other detention devices should be provided around the lower side of graded areas as Project No. 00-118-01 Page 12 ' 1 Agodoa August 3, 2000 required to control the transport of eroded material. The lower edge of the silt fence fabric should have "J" shaped embedment in a trench extending at least 12 inches below the ground surface. Surface drainage should be directed away from slopes and exposed soil areas should be planted immediately with grass and deep rooted plants to help reduce erosion potential. Hydro-seeding techniques will likely be required to seed steep slope areas. Tree cutting should be minimized on the slope areas. Pruning or trimming of trees with a minimum of disturbance to the existing slope surface and vegetation is preferred as opposed to felling. If felling is required, stumps should be left intact to reduce disturbance to the shallow soils. Plan Review This report has been prepared to aid in the evaluation of this site and to assist the owners and their consultants in the design and construction of the proposed development. It is recommended that this office be requested to review the final design drawings and specifications to determine if the recommendations of this report have been properly implemented and to make any supplemental design recommendations which may be required. Observations During Construction Our evaluations regarding slope setbacks and stability are based on the assumption that all foundations will be placed on undisturbed dense/hard natural soils beyond the recommended minimum slope setbacks. All footing excavations should be observed prior to placement of steel and concrete to see that footings have proper setback and are founded on satisfactory bearing materials and that excavations are free of loose and disturbed materials. Drainage and erosion control systems should be observed to verify proper construction. Fill placement and compaction should be observed and tested by a qualified testing laboratory. Project No. 00-118-01 Page 13 Agodoa August 3, 2000 CLOSURE This report was prepared for specific application to this project and for the exclusive use of Lawrence and Shirley Agodoa and their representatives. The findings and conclusions of this report were prepared with the skill and care ordinarily exercised by members of the local geotechnical profession currently practicing under similar conditions. We make no other warranty, either express or implied. Variations may exist in site conditions between those described in this report and actual conditions encountered during construction. If conditions encountered during construction appear to be different from those indicated in this report, our office should be notified. Respectfully submitted, GEOSPECTRUM CONSULTANTS, INC. \j-. 14,(/v-a4 D00James A. Doolitt $of WAsy1l ` 1?' Principal Engineer ,� Encl: Figures 1 and 2 ! #. •A R 23623 Dist: 1/Addressee o 8crs 2/Donald King Architects s1orvA1. � EXPIRES ins,U 2-- Project No. 00-118-01 Page 14 i if1 1 -- , I 1 , i y.rj:• x,e2j . �, � , 0 i ;� Ia • ,,:r Woodmont. B .c :.— _1` 546 (' •f(.471 �L/ 3M � �lg . . j Qsso • ., 4 /20 POVERTY • itio4i . .% . v B A Y -•f 3 .:' 'VI ii• •.B.1 Tower.. /' 33. �• f i d.. 346 _ SITE" : �i- �(%,\r;,. '.A.,:Gaon 0 \. , i• I' j'» , 138 u 1 ,08 Q ...:,.... 0s�� 4e 'a / 2 21 K._ 1. I/'•1 I�` �)rst7-,-----7 T. i�t e -.4 �Qis I j �1:. • r i-- Piling° b ';a:.:::.,,.5` ( ;� ''\ 2.2 , / (: 'T'`.,,,....„.„,....-..‹.*:;::''...>'1 '. .,_\ IV l 7 /r ----- L j�1 It > /`i�� P ^ I \J ram_'' x,, , ) 1 4 • .::%.., : •..\, I 1••,I �� \\ <14) e—CY" .*:*:..:-:.i......::.: .....***:-:`. ...::_,,----:::-....::• :',:::•:••••:-.:1:.•i'•71;,,i -:-';'::•:!.::i.ri;::' Q9 , 5/6 ,...... . ..... ..':�� Qgt �:. . (�::�..` [•`�� • �r •:fie (I�`-�.,' �.- -_ rl• «,..... ......;:', . ,•;:..•.:............---.5,...;.....'•N, :....-..:::•:3.$.4::`;F:.:?..,. s...;..,;•::: ••;„; '' 44): , \ --) , ..221..- I ‘'.., ../..::.•,':• •'••' r::::%*.:•:.•.:i:.:A'.•.'. ''... ';'/,...:. .,;-.7.-.7."--7-7 .ti's: k *:::•.(.•11 A :�:�••.....- -.. ref: Geologic Map of Poverty Bay Quadrangle, Washington • By Howard H. Waldron, USGS Map GQ-158,1961 Scale: 1" = 2000' SITE VICINITY GEOLOGIC MAP Proposed Agodoa Residence GEOSPECTRUM CONSULTANTS, INC Lot 23, Marine ails #17 miiiiiimmiiiiing Federal Way, Was hington n ton .... : nr. ^A • .X ' fi .' vv'.:.:..�:Gootochn/co/Enp/noor/np and Eorth Sc/oncos • Proj. No.00-118 Date 8/00 Figure 1 . . . ., .4 . 1 7°) •14.01 4. '' ••''' .0.0 • /0/..4% .. 1,r- . •,.z, ../t, / • :7.4':,..,,,/ 4, •n.re ye* ' /4":"..,:•`"i*' .. ' //V/ •*:•,..y'4'.4::',... ./...", ..tt 441 am toy, •. 14.-,/ /,, ., •„;Se; ..,;;;:..24,;"..q -N-AfAir ..1•''' 411 17 cr "AI .,,.. 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SC1 11.1;C.. , ‘... gum i c,.. • • 1 i 1.1 Ill(.10-.../.$11 C1'.4 11.71.....D.114) /....,.44•Eimassielik""•7 . \„ rc.,77-0 "4 j, • ,10.61 (c "11.1 \ \ • Z"1 •"i' WIC KRA 3.• .',1\ L.00.. '.1 • ii ' .4‘• 'i 3\C.1C ; it ,.. / , . 1:/-1 '0,1,i ii / Zaltiallilmvp,. 1 r-z, ; - i 306.4 AY,11411'7 ..., -, ......,.;,..). i \ i 111;C14 Ir+V 14.1 • / •••*...c..1 10,1 v ', i X i1/Cv/Er 1,1. I 7.....i v tow -,-i g - .• T., ,• I / I . i • , , . . • i /,,,f.-..,, . • r:. :,•• : pc....,-217--„, ,.... ! ...• \A.,..0.... / ,co.pcx , Zi? • ...**'...,. \ /7./0. -- ) ''i.,,ill't.r41-44,-.5.,[1_ 1,1) / c zr cac c.1;se : • • • '‘*s..S.- , ,8.,.,Q,..„1 I ,10-7--741 g7.6.- / C li•CC.0 Iv WA' Wig au.17,41.-- • I ••••I 1271 I IC 14.DU V-114.1. / C 1a•Ca.1.1$1.11 I Li ' : i1 it•••••7•4! . *11',Cia,(•t7 (II'C01.11.-113.1. C''....7,45. I • i .; ; . „ [S•CO1C v.143.r lc. c r 00340 1.131... ref: Boundary & Topographic Survey.for Agodoa Penhallegon Associates Consulting EnginieersI Inc dated 7-26-00 SITE EXPLORATION PLAN Proposed Residence Site GEOSPECTRUM CONSULTANTS, INC. Lot 23, Marine Hills #17 Federal Way, Washington ,s.c..toocohnIccztl ErigInap•arlrug and Ectrth Selcancars Proj. No.00-118 Date 8/00 Figure 2 • APPENDIX A FIELD EXPLORATION Our field exploration included a site reconnaissance and subsurface exploration program. During the site reconnaissance, the surface site conditions were noted, and the locations of the borings were approximately determined. Elevations of the borings were based on the approximate locations and the topographic data of Figure 2. Borings were advanced using a special portable power auger equipped for soil sampling. Soils were continuously logged and classified in the field by visual examination, in accordance with the ASTM Soil Classification system. Standard Penetration Tests (SPT) were performed in the borings using a standard (1.4- inch inside diameter, 2-inch outside diameter) split spoon sampler and 140-pound driving hammer falling 30 inches. Blow counts for each 6-inches of penetration were recorded in the field. The number of blows required to advance the sampler from 6 inches to 18 inches of penetration is the "N" value of the SPT shown on the boring summary. Logs of the borings are presented on the boring summary sheets A-1 through A-5. The borings summaries include descriptions of the soils and pertinent field data. Soil consistency and moisture conditions indicated on the logs are interpretations based on the conditions observed in the field. Boundaries between soil strata indicated on the logs are approximate and actual transitions between strata may be gradual. BORING NO. 1 Date: 5/24/00 Elevation: 150' Depth Slows Class. Soil Description Consistency Moisture Color W(%) Comments 0_ 5 ML Silt/Sandy Sift w/wood @ 1' frjm moist brown 2- stif Bra ML Silt very stiff ro 7 to hard 37.4 4 - 6- 35 8 - _ 57 SP anoddravelw/occ coarse sand ieVse 10- Tense 54 7.2 12- 14- SM Silty,Gravelly Sand 16- 51 SW Sand f-m 14.4 18-' Maximum depth 16.5 feet. _ No ground water encountered. 20- 22- 24- 26- 28- 30- 32- 34- 36- 38- 40- GEOSPECTRUM CONSULTANTS, INC. Proposed Agodoa Residence Lot 23, Marine Hills #17 Geofechnical Engineering and Earth Sciences Federal Way, Washington Proj. No. 00-118 Date 8/00 Figure A-1 • BORING NO. 2 Date: 5/24/00 Elevation: 166' Depth Blows Class. Soil Description Consistency Moisture Color W(%) Comments 0_ 7 I`Sir , Silty Fine Sand/Sandy Silt s000 se/ moist brown FILL 2_ renim 4-' 5 dk bm 23.6 ML very Fine Sandy Silt w/occ roots stiff very Igeoybm 6 - 10 to wet 27.6 8 _ ML S�o�lay�exdsilt pp+2.0 stiff tovery wn 29.7 14 10- SM Gravely Silty ana- eaium 33 SM Silty very fine Sand �ense moolst Drown 25.3 12- 33 ML ve Silt/Sandy Silt to hardff 14- _ SM Silty Sand w/gravel and clay €sense 16- 56 dense brown 17.3 18- Maximum depth 16.5 feet. No ground water encountered. 20- 22-" 24- 26- 28- 30- 32- 34- 36- 38- 40-' GEOSPECTRUM CONSULTANTS, INC. Proposed Agodoa Residence ., <° Lot 23, Marine Hills #17 Geofechnica/Engineering and Earth Sciences Federal Way, Washington Proj. No. 00-118 Date 8/00 Figure A-2 BORING NO. 3 Date: 5/24/00 Elevation: 171' Depth Blows Class. Soil Description Consistency Moisture Color W(%) Comments 0- 3 MIL Silt/Sandy Silt w/occ roots soft to moist browm 21.0 FILL 2 v moist ga?dbm 26.7 8 ML Silt very stiff moist red brn 4- 6- 11 28.7 & Silty fine Sand & Sandy Silt dens moist to ra - 8 - 23 L &v. still v moist Drown 10- SM Silty fine Sand w/gravel dense to moist 50/6' 12- Maximum depth 11 feet. 14- No ground water encountered. 16- 18- 20- 22-" 24- 26 ' 28- 30- 32- 34- 36- 38- 40- GEOSPECTRUM CONSULTANTS, INC. Proposed Agodoa Residence Lot 23 Marine Hills #17 Geofechnical Engineering and Earth Sciences Federal Way, Washington Proj. No. 00-118 Date 8/00 Figure A-3 � r BORING NO. 4 Date: 5/24/00 Elevation: 159.5' Depth Slows Class. Soil Description Consistency Moisture Color W(%) Comments 0 Sit fine Band/Sandy Silt loose to moist brown 11 M_ w>)org and rootlets m. dense 21.7 2— S fine Sand w/occ gravel gray 11 ML Silt stiff7.5 4 Maximum depth 4 feet. 6— No ground water encountered. 8 10— 12- 14- 16- 18- 20- 22- 24- 26- 28- 30- 32- 34- 36- 38- 40— GEOSPECTRUM CONSULTANTS, INC. Proposed Agodoa Residence Lot 23, Marine Hills #17 Geotechnica!Engineering and Earth Sciences Federal Way, Washington Proj. No. 00-118 Date 8/00 Figure A-4 1p . Emmi17, orimmiNINeer BORING NO. 5 Date: 5/24/00 Elevation: 151' Depth Blows Class. Soil Description Consistency Moisture Color W(%) Comments 0 ML Sandy Silt w/fine ro tlets 28nd oft to moist brown 8 occ decayed woodrm 25.7 2 stItf t gra bm 29.2 4 _ 8 ML Silt v. sti�f ad re bm SM Silty Sand w/gravel f-m dense 6-' 45 7.2 gray bm 8- Maximum depth 6.5 feet. No ground water encountered. 10- 12- 14- 16- 18- 20- 22-, 24- 26� 28- 30- 32- 34- 36- 38- 40- GEOSPECTRUM CONSULTANTS, INC. Proposed Agodoa Residence Lot 23 Marine Hills #17 Geofechnical Engineering and Earth Sciences Federal Way, Washington Proj. No. 00-118 Date 8/00 Figure A-5 0 I %A.; ';1°41.° t7 ,or k,r a DKA planning nrlih, architecture interior design Transmittal design management Date: 03-01-01 Project: AGR 9912 To: City of Federal Way No.of Pages: 2 33530 1st Way South P.O.Box 9718 Federal Way, WA 98063 Attention: Jane Gamble CC: From: John Stucky Re: Agodoa: Site Plans Sent via: Fax No. Courier Overnight 2-day UPS k US Mail email Comments: Jane, Thanks for your assistance with the Agodoa Residence. Enclosed are two full size site plans(one Civil, one Architectural)for the Pre-application Conference. Please let me know if there is anything else I can do from this end to help expedite the process. Thanks, John 2107 Elliott Avenue, Suite 305 Seattle,WA 98121 phone 206.443.9939 fax 206.443.9891 www.dkarch.com CITY OF G • FryCITY HALL 33530 1st Way South (253) 661-4000 PO Box 9718 Federal Way, WA 98063-9718 February 14, 2001 John Stucky DKA Architects 2107 Elliott Avenue Suite 305 - r II F Seattle WA 98121 RE: Notice of Pre-application Conference File no: 01-100602-000-00-PC; AGODOA RESIDENCE 514 South Marine Hills Way, Federal Way • Dear Mr. Stucky: The above referenced proposal has been assigned to me as project planner. At this time, the application and preliminary site plan have been routed to the members of the Development Review Committee. A meeting with the project applicant and Development Review Committee has been scheduled as follows: Thursday, March 8th -- 9:00 AM Mt. Adams Conference Room, City Hall, First Floor 33530 1st Way South Federal Way, WA 98003 We look forward to meeting with you. Let me know if you will have more than four people attending the pre-application meeting so we can make arrangements for a larger room. Please call me at (253)661-4120 if you have any questions. Sincerely, *At&um.h (-4 Jane Gamble Associate Planner L:\CSD-1DOCS\SAVE\66042498.DOC '• * St-smolt, RECEIVED BY MAST LAND USE APPLICATION CITYCIP COMMUNITY DEVELOPMENT DEPARTMENPEPARTMENT OF COMMUNITY DEVELOPMENT SERVICES 33530 First Way South 414 EMF FEB 12 2001 PO Box 9718 Federal Way WA 98063-9718 253-661-4000;Fax 253-661-4129 www.ci.federal-way.wa.us APPLICATION NO(S) 0 I ( 00 v T 0 �" - PC Date 2 i i D Project Name A q ® d 4 X`S C t Property Address/Location r 1 5 n""\ '/)l(S 11"' Parcel Number(s) VT 7- 3 0 Z 3 /' Project Description 141{ (4-' 5 r v-w�- 'f� 4 3 - ( t ( 5 .\f (€ , , PLEASE PRINT Type of Permit Required Applicant Annexation Binding Site Plan Name: 0 k 4 Boundary Line Adjustment Address: 2=1:4bre Z( '7 rz(1,'0 f 4v.-e Comp Plan/Rezone Land Surface Modification City/State: 5 ,� (f jt w4 Zip: 1 ><' 1 Z I / Lot Line Elimination Phone: O(, K Preapplication Conference 2 - K / 3 5 1 3 Process I(Director's Approval) Fax: 2 O C - K`'( 3 - q ri Process II(Site Plan Review) Email: Q,'ti h a © d k a r cc H, Process III(Project Approval) Signature: Process IV(Hearing Examiner's Decision) Process V(Quasi-Judicial Rezone) Agent(if Different than App Process VI SEPA w/Project Name: SEPA Only Address: Shoreline: Variance/Conditional Use City/State: Short Subdivision Zip: —Subdivision Phone: Variance: Commercial/Residential Fax: Email: Required Information Signature: A S - /s. 0 Zoning Designation Owner F ,1 d Comprehensive Plan Designation Name: (-41- ) 4 S4,Y � /I-4 o Imj. q —a Value of Existing Improvements Address: Z ( Z a fie,a(,t 1,,,(, )z a P r,1,c 501*--1 �d aw0. City/State: 0.e s j'1 -A e-5 (y S Value of Proposed Improvements Zip: 7 g ( y / Uniform Building Code(UBC): Phone: ( z f'3) q i`-sr6 Z -3 Fax: Occupancy Type Email: Construction Type Signature: Bulletin#003-October 30,2000 Page 1 k:\Handouts-Revised\Master Land Use Application Mar 12 01 12: 36p I K A 2061443-9891 p. 1 .:'�.i:}'��.-"i,Y••`h'� 'gip_y.„",,'.-« Dla3 '`7,7 L}, 1i,. I 7 I .' DKA . �'• planning ,;, Kip' ry,1 Fax Transmittal °_ interior design design management Date: 03-12-01 Project: AGR 9912 To: City of Federal Way No.of Pages: A(including cover) City Hall G P.O. Box 9718 Federal Way, WA 98063-97I8 Attention: Jane Gamble CC: From: John Stucky Re: Agodoa: Indications of original grade Sent via; E Fax No.(253)661-4129 Courier Overnight 2-day UPS US Mail email Comments: Jane, I'm returning a portion of the drainage information that shows the site, It is obvious from this topographic information that the area at the time this mapping was done is quite different from what it is now_ The area in question shows a more gradual slope what is shown in more recent topos. I've also included the pertinent pages from the Gootech Evaluation referring to the borings that were taken and the amount of fill soil that covers the natural grade. Hopefully this will be enough to explain how the condition of the site has changed over time, but 1 will still pursue Geospectrum Consultants to see if I can obtain a written statement that will confirm that the grade is engineered_ Thanks, John 2107 Elliott Avenue, Suite 305 Seattle,WA 98121 phone 206.443.9939 fax 206.443,9891 www,dkarch.com Mar 12 01 12: 36p " K Fl 2061443-9891 p. 2 i/i J? // „,...•''-------._....,_--------- MIM - _-- Li_ a 1r.1.1.1.77 ir' L:N6 a ,. / / ESP Dk � r Ir / 1 / .# g5'I ' P 13 .5 L►dE FRlI 'Ig.° yip of in B�00 S pGE Egg t .4' b1 / a 9s/Ii..7/r 0 /D D,4R►� '.� .',Z' G C= v /86. /o -�. / / �x Tr/v o //)---c:I. 1 V i?' /...6Z,s4/ / ',.r�— N1." -7,47 /6", % k O \♦'sue' 4 ..5 ,. 70 72 , /Z Cd� itiethi /°z 8aZ G�t..�i�rEHl�oN ._ a 0 Time,r�'EE/' 2,s/LE � V P. /,6Z. ,r 6/Or - �2 9; b v.�D�'O�Ti�/LS \ k/i 4 i /.�f...5� /9 / :°�:.G1?.. /vim 3 i/c�t1�;l�I �� Nv /-_96 B ; �' 2 F . ...,,,:v , , ._. . ,. .2....„ g.loti k 4---.5- Sitilhod i.4„ •---7r-• .70 all'OPIL4p711.''. ... ...,c-•'\l'hr°4'..AiSlY .41;496-. .,;7-:/z, __ - , . $ 741-0 girial .:41t,.-4,,,,4, 1,,,„: , 'i 7.5 a,1.(77/Y, /S: ;4 /A:4= -N,,,..-'' _<-,litt . /1',. 1 A .6�. Q' �T. � • 4� \ �4' ,��� ` T /6 ` 'r' '% = i6A r TOE / t3� / . S vt� /�.SS� `� \�� ii f) V 11/ - -. - \b cl ----______* t/ v y .--, ,,,,,,.., _ , e . Op(!) ....-cs I i \f,1/.f'T/.w erg N • ply ��o��ti \ v �/ l'‹-c) — \' Lri'ZX: 45- ) — �- Gam/ ; ) u v� 1 .� . `� BLOC 4 Mar 12 01 12: 36p K FI 2061443-9891 p. 3 IFAgodoa August 3, 2000 Based on the topography of Figure 1 the total height of the bluff is indicated to range from about 80 to 100+ feet. We did not observe any evidence of instability such as ground cracks or anomalous surface topography within the moderately sloped building site area of the property however we observed evidence of slope failures on the very steep north bluff slope. We observed two existing landslide areas on the very steep bluff slope which included a large slide near the top of the slope at the east property boundary and a smaller slide near the toe of the slope below the northwest property corner (see Figure 2). An existing gabion wall (wire cage rock wall) was apparently constructed in the past to help stabilize the lower slide area. Both the upper moderately sloped building area and the adjacent bluff slope were generally well vegetated. The building area was covered with grass in the southern 2/3 and heavy blackberry growth In the northern 1/3. The bluff slope vegetation included blackberries ferns, salmon berries, alder and maple trees and occasional fir trees. Subsoils Subsoil conditions were observed in our subsurface borings and in the slide scars and shallow test pits excavated in the very steep bluff slope. Five subsurface borings were drilled at the approximate locations shown on Figure 2 to depths ranging from 4 feet to 16.5 feet. Logs of the borings are presented in Appendix A. Subsoils encountered at the boring locations in the upper site area generally consisted of alternating layers of silt, sandy silt, silty sand and sand_ Borings 2 and 3 drilled along the upper east side site_encnlintered an estimated 1 to 3 feet of loose/soft fill soils_ Generally the weathered natural soils (at the surface or below fill soils) were also loose/soft to depths of about 2 to 3 feet. The less weathered natural soils were found to be generally stiff to very stiff and dense to very dense below depths of about 2 to 3 feet below the natural ground surface. • Soils observed in Boring 1 at the top of the bluff combined with observations of our shallow test pits on the bluff slope and observations of the upper landslide scar indicate that the soils in the upper half of the bluff slope consist of layers of very dense silty sand with gravel and sand with gravel. In addition a layer of hard silt was encountered to a depth of 8 feet in Boring 1 and another silt layer was observed in a slope test pit at about elevation 105. Glacial till-like silty fine soils were observed in our shallow test pits in the lower half of the slope and were also exposed in the lower slide scarp. Ground Water, No seeps or springs were observed in the building site area or on the bluff slopes and no free ground water was observed in any of our borings_ Soil samples obtained from Project No. 00-118-01 Page 3 Mar 12 01 12: 36p " K R 206J443-9891 p. 4 1 r /� • /,.//�" 19 .1,,t, _...,_ ,..:044 ..//,/,,....„.74w; A. ` • • �____- `�� c?L.,//////////�J-�� J/'^ ✓;�%%�i� 5.s°i! cow k.r,Ct It. .� �'/ a:NS L''•.1W.nCq/ihL) EXlYStiriCJ--" ri . 1.-. ;`.- ;. a•.,..~ '' `s'`•r� ;..;7.'; 1 ij,. ;%// %. _•.1 , i Approximate Landslide . : i..gl -f � •`r ='* � limits of existing a. uI Y.N.W"it/ = /,�,/� �•..1_ "ti••--. , 'y-;,. landslide oleo a .'.....'!4%;/.1P i / y//61.„.• • .1,,,•-•-.75,•<::..../.....,e1. \ / - x 1. '-'.•A,e,%, ,../,',-,/...:':;-'4,-,, ,-.. ''' .- •' •.i I • 1) 0-c.,:,,„ - :./ // H / / //,,, 0 C lfikil wk u11L� // j /-/ /Ir �! u.,tse / 1 •l. N •yq„•i r , i•cit r`+,N l!(IV.k1 .LOLL.o, Z) : 1 vi . / ) '-• \,1 , ' V a.r, I1.I 6 ItI . i I .1 I ' \\ • ' ! I 11III;fI� \ `` . ' i ; \, "toae.,.... /ztl� • • l s I i I I I i , Nit , 11 I 1/� ►Jl � ,011.41 1- � I i \ �CV11w: .Ct M �iLfM 0 y 7.1 (tt440ttL1I �� .I )1 qi-10 s arI s4+`.\LN,� G •1,11s.4 1 l I\ w 7,fit`/ ,1..L 'lu ' ,9 i \ \ / 10,01.000.4111[vL,l a;`✓ / _u1,04 MG1M1 I R gN ew k`.. •71.1y{ / •., f R IV br CC:�.LY / �^'�'�'.,tiir ,)w.,`I , �� / tr �G rrl l i 1.1 f r `� ,.�p Qt'A 1 j,lS.,/ 1 k71 s - it - 1[/ i GPyr!) ,lR. ` ;Earn Fr•Iw.— ,'muc,.11 v (NC N•' I i t.'(NC u. 1' • .'iYC I.,/4.1.1' f U.Ow."1.0.. t ref: J3ounclai-y & r3 JE oyraphic Survey .for Agodoa Penhallegon Associates Consulting Enginieers, Inc dated 7-26-00 SITE EXPLORATION PLAN Floposed Residence Site GEOSPECTRUM CONSULTANTS, INC. Lot 23, Marine Hills #17 `:'•`t o -,i1:`:ar t81,r§-,' ..1. ,x.".<,• "i ,�. Federal Way, Washington • .jam Goorepchn/cQ/Enp/n1®or/r,l2 and EOY7h S /tun=ad Pro]. No.00-118 Date 8/00 Figure 2 __. Mar 12 01 12: 37p - K R 2081443-9891 p. 5 BORING NO. 2 Date: 5/24/00 Elevation: 166' Depth Blows Class, Soil Description Consistency Moisture Color W(%) men cis Stet/ Silty Fine Sand/Sandy Silt Ioo e/ moist brown • FILL — 7 sof tl z reQ prn Ltm 5 dk bm 4 23.6 ML very Fine Sandy Silt w/occ roots stiff ve y. gr ybm 27 6 10 G ,J v t ► ^ 14 ML S oceclas'aXdSilt pp+2.0 �erytstiff wnm 29.7 5�c 10- 33 . Snrr v1avety Siiiybana medium ry pp Vy 12_ SM V Silty very fine Sand cerise morylst gian 25.3 ML very stiff 33 Silt/ Sandy Silt to hard 14- SM Silty Sand w/gravel and clay dense 16" 56 dense brown 17.3 18- Maximum depth 16.5 feet. No ground water encountered. 20- J 22 24H 26- 28- • • 30- 32- 34- 36- 38- 40-4 . .. 1 GEOSPECTRUM CONSULTANTS, INC. Proposed Agodoa Residence t . .�zE Lot 23, Marine Hills #17 Geotechnical Engineering and Eartfi Sciences Federal Way, Washington Proj. No. 00-118 Date 8/00 Figure A-2 • Mar 12 01 12: 37p - K R 206) 443-9891 p. 6 BORING NO. 3 Date: 5/24/00 Elevation: 171' Depth Blows Class. Soil Description Consistency Moisture Color W(%) mmen1 0 - MIL Silt/Sandy Silt w/occ roots oft to moist b o FILL _ 3 � �Ci�t 21.0 2 bm v moist gra arld 26.7 8 ML Silt very stiff moist red bm 4 - 6 - 11 28.7 twt 8 _ SVLI& Silty fine Sand & Sandy Silt des moist to ra 23 ' �� v moist grown 10_ SM Silty fine Sand w/gravel der se t moist 50/6' V. densoe 12- Maximum depth 11 feet. 14- No ground water encountered. 16`1 18- 20- 22- 74- 26- 28 ' 30- 32- 34- 36- 38- 40-4 GEOSPECTRUMI CONSULTANTS, INC. Proposed Agodoa Residence .,,,. t ..t�. .,t..,.� Lot 23, Marine Hills #17 Geofechnical Fngineering and Earth Sciences Federal Way, Washington Proj. No. 00-118 Date 8/00 Figure A-3 CITY OF G MEMORANDUM F��/ Public Works Department FIN"33530 1 ST WAY SOUTH DATE: March 13, 2001 TO: Jane Gamble FROM: Jim Femling SUBJECT: AGODOA RESIDENCE- (01-100602-00-PC) 518 S 288TH PL After reviewing the materials submitted and a visit of the proposed site the following comments and findings address issues that need to be resolved prior to developing the site: LAND USE ISSUES Stormwater 1. Surface water runoff control and water quality treatment will be required per the 1998 King County Surface Water Design Manual(KCSWDM) and the City of Federal Way addendum to the KCSWDM. This project will meet the requirements for a Targeted Drainage Review,at the time of the site plan review submittal a preliminary TIR must be provided including a narrative addressing the relevance to the project of the 8 core and the 5 special requirements of the KCSWDM will be required. A Level I downstream analysis shall also be provided. The city has available 1"=100',5 foot contour,planimetric maps that must be used for basin analysis. Contact Kevin Peterson,Engineering Technician at 661-4126 for further details.The project lies within a level 1 flow control area,thus the applicant must design the flow control facility to meet this performance criteria. For site plan review submittal,a conceptual drainage facility should be shown on the plan to a size and configuration approximating the needs of the site. Traffic/R-O-W Improvements 1. The applicant may request a right of way modification pursuant to FWCC Sec.22-1477.The Public Works Director may modify,defer or waive the requirements of this article only after consideration of a written request from the owner. 2. All abandoned driveway areas must be removed and curbing and sidewalk restored to match existing improvements. 3. Driveways that serve single-family residents may not exceed thirty feet at the front property line. 4. Open cutting of the existing asphalt roadway is not permitted unless approved by the Public Works Department. BUILDING PERMIT ISSUES 1. Technical Information Report (TIR) will need to be prepared for the project and submitted with the building permit application. The TIR will require the signature/seal of a Professional Engineer licensed in the State of Washington. 2. The applicant will need to provide a geotech report that addresses design pavement thickness for the roadways. 3. The applicant shall reimburse the City for the cost of all required regulatory,warning and street name signs that are installed prior to acceptance by the City of all other require improvements. 4. Copies of Public Works' standard checklists have been included to assist the applicant's engineer in preparing the plans and the TIR. 5. Bonding will be require for all improvements associated with right of way improvements. The bond amount shall be 120%of the estimated cost of the improvements. Upon completion of the installation and final approval by the Public Works inspector,the bond value will be reduced to 30%of the original amount for the two-year maintenance period. An administrative fee deposit will need to accompany the bond to cover any possible legal fees in the event the bond must be called. 6. The developer will be responsible for the maintenance of the storm drainage systems. 7. When topographic survey information is shown on submitted plans, as may be required, the vertical datum block shall include the phrase"DATUM: N.G.V.D.-29"or"DATUM: K.C.A.S."on all sheets where elevations are called out. 8. All drawings shall be drafted/plotted on 24"x 36"mylar sheets with permanent black ink. Site plans shall be drawn at a scale of 1"=20'or larger. Drawings submitted for plan review shall be printed on 24" x 36"paper. 9. Provide cut and fill quantities on the grading plan. 10. The site plan submitted should show the location of any existing and proposed utilities in the areas affected by construction. l:\csdc\docs\save\50636931.doc Jane..amble- 87665417.doc Pagel CITY OF FEDERAL WAY DEPARTMENT OF COMMUNITY DEVELOPMENT SERVICES DEVELOPMENT REVIEW COMMITTEE TRANSMITTAL C• DATE: 3/8/01 TO: Jane Gamble, Associate Planner Y FROM: Mary Kate Gaviglio FOR DRC MTG. ON: DATE - Internal 3/8/01 - with applicant } FILE NUj ER(s) : 01-100602-00-PC RELATED FILE NOS. : None PROJECT NAME: AGODOA RESIDENCE c PROJECT ADDRESS: 518 S 288TH PL ZONING DISTRICT: RS 15.0 PROJECT DESCRIPTION: Pre-application - To discuss proposal to build 3- level single family residence and grade site on a vacant lot. Site contains steep slopes in excess of 40%. LAND USE PERMITS: Preliminary Plat, SEPA PROJECT CONTACT: DKA ARCHITECTS 2107 ELLIOTT AVE Suite 305 2064439939 (Work) MATERIALS SUBMITTED: Preliminary Plat conceptual drawing Comments as follows: Provide geo-tech report with recommendations for construction of retaining walls. Can be submitted • with this permit application or by separate permit. Provide height calculations and site plan with both existing and finish grade. Height survey by licensed surveyor will be required. One-hour shaft required for elevator shaft. 1-hour separation required on garage side, 20 "• minute door as required by code. Engineered design parameters: Exposure Zone C, wind speed 80 mph, Seismic Zone III. Verify that basement meets actual ti } ;Jane Gamble 87665417.doc Page 2 code criteria. } { $ Vf}f}i]A}}}}}p....}:'fF.•.VTTIT}iF. r:Y.V}}}:\•nF •.....}}}}T}}}h.}T}}:}}T}T}}.....r.rf.rrr.}}}::.....:f.V�.f•}.4}nN'•hvv4 h...}:}}h}}}T:}iin...nnr...CC%.......VF....n...r..r.•.•................r .nv.v»»v...............................v..%.v.........nv...nv CITY OF FEDERAL WAY COMMUNITY DEVELOPMENT REVIEW COMMITTEE SIGN-IN SHEET PRE-APPLICATION MEETING File No.01-100602 Agodoa Residence 518 South 288th Place,Federal Way March 8, 2001 64410—rwfJV enj►0tiM (.16t'1106 Ottc nk4 z-(j(- 7� 3� ” 3ti DV-4 a r tilikeY yo ()Al47 LAKENAvE)J UTILITY bis7Rlc7 'NV Sloe wAtnt�,( (� �� �t�L� . VA _( 53-Ica ( 4(q r TECHNICAL REVIEW (RESIDENTIAL) Agenda Date: March 8, 2001 Subject: Agodoa Residence/01-100602/Gamble To: Development Review Committee From: Greg Brozek — Federal Way Fire Department WATER SUPPLIES FOR FIRE PROTECTION A Certificate of Water Availability shall be provided indicating the fire flow available at the site. Fire hydrants shall be spaced 700 ft. or less apart. Every building lot shall have a fire hydrant within 350 ft. All measurements shall be made as vehicular travel distance. Fire hydrants shall be in service PRIOR to and during construction. FIRE APPARATUS ACCESS ROADWAY Fire apparatus access roadways shall be required for every building when' any portion of an exterior wall of the first story is located more than 150 ft. from fire apparatus vehicle access. Fire apparatus access roads: 1) Shall have an unobstructed width of not less than 20 feet and an unobstructed vertical clearance of not less than 13 feet 6 inches. 2) Shall be designed and maintained to support the imposed load of a 25 ton fire apparatus and shall be provided with a surface so as to provide all- weather driving capabilities. 3) Shall be not less than a 20 foot inside turning radius and not less than a 40 foot outside turning radius. 4) With a dead-end in excess of 150 feet in length shall be provided with a cul-de-sac or Fire Department approved alternative at the dead end. All such cul-de-sacs shall be not less than 80 feet in diameter. 1 5) Gradient shall not exceed 15 percent. 6) Serving a single residential property which have a dead end in excess of 150 feet in length shall be provided with a turn around approved by the chief. [K.C.F.D.#39 Administrative Policy Guideline No. 1006] EXCEPTION: When buildings are completely protected with an approved automatic fire sprinkler system, these provisions may be modified by the chief. Fire apparatus access road gates shall comply with K.C.F.D. #39 Administrative Policy Guideline No. 1001 (copy attached). AUTOMATIC FIRE SPRINKLER SYSTEMS An automatic fire sprinkler system shall be installed in Group R, Division 3 occupancies: 1) When the occupancy exceeds 2,500 square feet (including attached garages) without adequate fire flow. 2) Without approved fire department access. 3) When the occupancy exceeds 10,000 square feet. 4) When the building is classified as an over-water structure. Comments: The minimum fire flow for one- and two-family dwellings shall be 1,000 gallons per minute. If the slope of a building lot does not allow the building(s) on the site to comply with the "life safety/rescue access" requirement, the building(s) shall be provided with an approved automatic fire sprinkler system. Life safety/rescue access shall mean an unobstructed access to all floor levels and each roof level of a building on not less than 20 percent of the building perimeter by utilizing a 35-foot ladder. An alternate method would be at least one stairway enclosure with exit doorways from each floor level and with a door opening onto each roof level which conforms to the requirements of the Uniform Building Code. THESE COMMENTS ARE VALID FOR 180 DAYS FROM REVIEW AND ONLY FOR THE PLANS REVIEWED. 2 Greg Brozek - Assistant Fire Marshal 31617 1 Avenue South Federal Way, WA 98003 Phone 253-946-7241 Fax 253-529-7206 3 LAILHAVEN UTILITY DISTRICT 31627 1st Avenue South • P. O.Box 4249 • Federal Way,WA 98063 COMMUNITY DEVELOPMENT TECHNICAL REVIEW COMMITTEE AGENDA OF: March 8,2001 ATTN: Ms. Jane Gamble Associate Planner SUBJECT: Agenda Item No. 1 - Agodoa Residence 01-100602-00 (PRE) COMMENTS: Water and sewer service can be provided from South 288th Place adjoining. Please allow four(4)to (5) weeks for meter installation following application. By: Date: 3 0 Mary . Yo g • 71r Develo me Services pervisor Direct Line: (253)946-5400 FAX: (253) 529-4081 E-mail: myoung@lakehaven.org 0 :°,,. • I DKA planning • architecture n Transmittal d interiormanagement meatdesign management Date: 02-21-01 Project: AGR 9912 To: City of Federal Way No. of 4 City Hall Copies: P.O. Box 9718 Federal Way,WA 98063-9718 Attention: Jane Gamble CC: From: John Stucky Re: Agodoa Residence: Geotechnical Evaluation Sent via: Fax No.(xxx)xxx-xxxx Courier Overnight 2-day UPS ® US Mail email Comments: Ms. Gamble, Four copies of the Geotech soils report are enclosed. One of the concerns with the site was the"edge condition"running along the east property line indicating a slope in excess of 40%. From talking with our surveyor and confirming this Fernando Fernandez, we found out that the edge condition was not a problem if it could be shown to be manmade and not a natural grade. I was hoping to get permit/regrade information from when the house next door was built in 1977, but the Federal Way records only go back to 1990 and King County has limited records from before 1980. Apparently they experienced some accidental purging of record around 1980. However,from the Subsoils section of the Gotechnical Evaluation(page 3),we can see from borings 2 and 3 that we have "an estimated 1 to 3 feet of loose/soft fill soils"which changes the natural grade considerably. I hope this will be sufficient to explain the change in slope along the east property line. Thanks, John 2107 Elliott Avenue, Suite 305 Seattle,WA 98121 phone 206.443.9939 fax 206.443.9891 www.dkarch.com CITY OF FEDERA] ,Y DEPARTMENT OF COMMUNITY DEVELOPMENT SERVICES DEVELOPMENT REVIEW COMMITTEE TRANSMITTAL DATE: February 14, 2001 TO: Trent Ward, Development Services Manager Joan Hermle, Building Official Mary Young, Lakehaven Utility District Greg Brozek, Federal Way Fire Department FROM: Jane Gamble FOR DRC MTG. ON: 3/1 - Internal 3/8, 9:00 - with applicant FILE NUMBER(s) : 01-100602-00-PC RELATED FILE NOS. : None PROJECT NAME: AGODOA RESIDENCE PROJECT ADDRESS: 518 S 288TH PL ZONING DISTRICT: RS 15.0 PROJECT DESCRIPTION: Pre-application - To discuss proposal to build 3-level single family residence and grade site on a vacant lot. Site contains steep slopes in excess of 40%. LAND USE PERMITS: Preliminary Plat, SEPA PROJECT CONTACT: DKA ARCHITECTS 2107 ELLIOTT AVE Suite 305 2064439939 (Work) MATERIALS SUBMITTED: Preliminary conceptual drawing ,�E