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HomeMy WebLinkAboutCompliance Geotechnical Report - BLD Engineering / Geo-tech Reports (• Y, 'Al s � f 117 w F j h v �� (I2/16/2Q08)Grace Miller- Fw: Please define"Beyond"and "High water mark" Page 1 From: "Holten" <m kholten@comcast.net> o �, �,i{rtiH (0, To: "Grace Miller"<Gbm@co.mason.wa.us> J Date: 12/15/2008 6:17 AM .. /�, Subject: Fw: Please define"Beyond"and "High water mark" CC: "Michael Robinson" <michaelr@mc2-inc.com> Hello Ms. Miller, You may recall that our family met with you in July regarding a stair tower to the beach on Harstene Island. We have been delayed in our project by the inability to find a contractor to install pilings in a beach with shallow water and no access from the land side. We are in the final stages of design with our engineer. Our plan has changed in that we are hoping to install a concrete footing for the stair tower. We are wondering if the stair tower footprint is within 10 feet of the high water mark, can the final run of stairs jut further(about 5 feet)from the high water mark? Your input is truly appreciated, Mike and Kristin Holten Judie Schaaf -----Original Message----- From: Michael Robinson To: 'Holten' Sent:Wednesday, December 10, 2008 3:27 PM Subject: RE: Please define"Beyond"and "High water mark" You were going to need to put in concrete footings for the structure anyway, there should be no problem with the concrete pilasters going on top. The.majority of the tower should be well within the 10 feet of the high water mark. Although, the final stairs to beach will end approximately 5'-0"from the tower. This could put the final span slightly outside the 10 foot mark. Unfortunately, I don't see an easy fix for this, considering the need for the braced frames on each side of the towers. You can remove the portion of the bluff that interferes with the ramp. This is called out on the Left Side Elevation on sheet S1.0. Let me know if you want me to revise the drawings to include the concrete pilasters. Sincerely, Michael Robinson, EIT (V116/2008) Grace Miller- Fw: Please define"Beyond"and High water mark" Page 2 Engineer MC Squared, Inc -----Original Message----- From: Holten [mailto:mkholten@comcast.net] Sent: Wednesday, December 10, 2008 6:50 AM To: Michael Robinson Cc: Mike Szramek Subject: Re: Please define"Beyond"and "High water mark" Michael, Will the Dept of Fish and Wildlife and other agencies approve the pilaster and glu-lam design in the marine environment? Is everything still within 10 feet of the high water mark? Do we need to show the detail of the final stairs to the beach so it can be calculated as part of the footprint or does it fit within the current footprint? Are we allowed to remove the bluff where it interferes with the ramp? I think this is detail 2 on page 1 of the drawings. I think our geotech study puts the upper concrete anchor foundation 10 feet from the edge of the bluff. The bluff slopes upward at the edge too-so it might reach without having to cut the bluff. Kristin a I 1 I i i i i k i 3�+�ao�s�oogsy MARTIG ENGINEERING P.O. Box 11850 Olympia, WA 98508-1850 S� (360) 754-9687 Fax (360) 705-0789 July 9, 2008 Mason County Department of Community Development Public Works 426 W. Cedar P.O. Box 578 Shelton, WA 98584 Attn: Allen Borden, Planner Re: Compliance Geotechnical Report for: * Property Owner: Judith Schaaf (360) 482-5539 11502 126th Ave. Ct. E Puyallup, WA 98374 * Contact/Representative: Mike & Kristin Holten (253) 446-1054 * Site Location: Hartstine Island 1030 E Sunset Hill Rd. Shelton, WA 98584 (Take SR 3 from Shelton toward Bremerton; Turn Rt on Pickering Rd; Cross bridge onto Hartstine Is; Turn Lft on North Is Dr; Turn Lft on Sunset Hill Rd; Proceed west then south to 1030 E). See the Attachment 1 Vicinity Map. * Tax Parcel Nos.: 22134-12-90040; * Mason County: Sec 34, Township 21 N, Range 02 W; * County Permit Numbers: SWG2007-00609 * Proposal: Construct: (i) a new 4-Bedroom Single family residence with attached garage; (ii) a Tower-Style Stairway adjacent to the Marine Bluff Bank for beach access; & (iii) a 2-Bedroom auxiliary dwelling unit, on the subject property (Phase 2). Dear Mr. Borden: I, Kenneth W. Martig, Jr., PE, of Martig Engineering have completed my engineering investigations regarding the requested Geotechnical Report associated with the above referenced property. 1 x .r PROPOSED ACTION The Proposed Action at this site is to construct a new single family residence upon the above referenced property, as shown on the Attachment 2 Property Layout Map, the Attachment 3 Site Plan Map, and the Attachment 4 Stair Tower elevation view. The access driveway into the property has been constructed and protected against erosion by covering it with a layer of 3-inch minus fractured rock. A 6-bedroom Septic System has been approved for construction, SWG2007-00609, and the new Well construction is pending (at the location shown on the Site Plan). The 4-bedroom residence and the stair system to the beach will be constructed as soon as the County Permits are obtained. The 2-bedroom auxiliary dwelling unit, ADU, will be constructed at a later time as Phase 2. SUMMARY All site slopes greater than 15% are controlled by cemented Till, inherent at shallow depths within the present Hartstine series soils. Therefore, existing undisturbed site slopes are very stable with portions of the Marine Bluff Bank standing adverse or vertical. The newly constructed neighboring single family residence, on the adjacent property to the south, was inspected for signs of induced slope instability and/or erosion of disturbed surfaces. None were found. As a result of our investigations, we can affirm that all potential Landslide Hazards can be overcome in such a manner as to prevent harm to property and public health & safety and that no significant Environmental Impacts will result if this Proposed Action is permitted as outlined within this Geotechnical Report and its attachments. The following discussion summarizes our: Site Investigations; Research of Site Conditions; Analyses; and Conclusions, allowing this Geotechnical Report to be completed for the above referenced site. 2 1 GEOTECHNICAL REPORT 1. Geologic Conditions: a. Topography-- An enlarged section of the USGS Mason Lake Quadrangle Map shows the general topography of the site and its surrounds (see Attachment 5). This map shows slopes vary up to 40%. It also shows that the subject property is situated upon a small ridge/hogback, sloping primarily toward Pickering Passage to the west, but also toward minor ravines located both north and south of the property. Note that there is hardly any offsite tributary runoff area, since the watershed ridgeline is located only 400-feet to the east. The 6400t contours and the two elevation views on Attachment 3 show the measured topography and critical slopes of the property in greater detail. No evidence of surface water runoff was found on this property, even with the heavy December 2007 rains that fell upon the constructed entrance driveway. b. Soils Types-- The Mason County Soils Survey shows two classifications of soils that influence this site (see Attachment 6): (i) Hb, Hartstine gravelly sandy loam, 15 to 30%-- a granular unconsolidated well draining surface soil layer from 24" to 30" inches thick, supported by a 2' to 6' deep weakly cemented Till that then becomes strongly cemented, continuous to great depths. We found that j the slopes dropping into the north and south ravines were greater than the published 30%, almost 40%, and that the Marine Bluff Bank to the west had an average slope of 0.5' Horizontal to 1.0' Vertical (200%). At places where top of bank erosion has subsided, the exposed bare Till bank stands stable with adverse and vertical faces. The 4-bedroom &2-bedroom residences are located within this soil i classification, on slopes of 18.6% to 22%. (ii) Ha, Hartstine gravelly sandy loam, 5-15%-- This soils series has a granular very-friable gravelly gritty sandy loam upper soil layer 24" to 30" and underlying Till like Hb above. The difference is that the slopes are not as steep. The Septic System Drainfields are located within this soil classification. Soils test pits were dug on the property to locate the Septic Drainfields and confirm the above described Hartstine soils. The findings are shown on Attachment 2. i 1 I i i i i 3 R 1 it '7i 1 1 '� s.. S' , r• y NAP WWI #1Typical of all soils test Holes/Pits #2 Excavated soils after being Rained-On c. Ground Water Conditions-- No evidence of a soil layer containing ground water could be found at the site, inspecting visible soil at elevations above low tide. No signs of groundwater emerging from any of the site slopes, either natural or man-excavated, could be found. When the Well is constructed, the deep groundwater bearing formations will become identified. During the winter wet season, a very shallow water table condition develops on top of the Till layer at the base of the granular surface soil. This is a temporary condition. Due to the sloping nature of the property, his water quickly migrates laterally as Interflow thru the granular upper soils into the adjacent ravines or dripping down the face of the Marine Bluff Bank onto the beach. 4 •,..� K � h #3 Water perched upon Till 1/8/08 #4 Water gone 1/26/08 4 d. Related Upslope Conditions-- As shown on the Attachment 5 Topography Map, upslope ground slopes are less than 15% and no surface or ground waters reach the site. No surface water conditions exist either. e. Surface Water Runoff-- No surface water runoff is tributary to the site and no evidence of onsite surface water runoff was found.. All precipitation falling on the undeveloped site and constructed access driveway infiltrates into the granular surface soil layer. Photographs #5 & # 6 show no signs of surface erosion from overland flow, even after heavy December 2007 rains. #5 Looking east, @ west end of #6 Looking west along bottom of access driveway adjacent southerly Ravine f. Noted Landslide Activity-- No signs of significant landslide activity were found on or near the site, either on natural or manmade slopes. Stereo Aerial Photographs were examined for signs of Landslide activity. None were found. Photos taken 6/19/85 & 7/30/03 show no signs of earth/slope movement as presented on Attachment 8. No clumps of trees are missing along the shore line during the 18-year interval, nor are any along either ravine. Only very minor, insignificant stuffing/wasting was found at isolated locations along the Marine Bluff Bank. Three types exist: (i) Freeze-Thaw with root wedging-- This wasting involves freezing of bank face moisture, causing ice expansion between soil particles. The thawing creates open space between the particles, which allows more moisture storage. Tree and brush roots seek this stored moisture, entering into the space between the expanded soil particles. As the roots grow, they act as wedges, further expanding the space between the soil particles, creating cracks that can receive more bank face moisture. Finally, a Freeze-Thaw 5 cycle causes chunks of bank face soil to fall as shown in photograph #7. Photo #8 shows where these chunks fell from. #7 Chunk bank face failure 0 8 Original position of chunks Mechanical/Leverage-- This bank wasting involves top of bank failure when large trees become situated at the edge of the top of bank. During winter surface soil saturation, coupled normally with high winds and or ice/snow loads, these large trees pry loose portions of the top of bank. Photograph #9 shows such a large tree after such a bank failure. Photo #10 shows the resulting localized slide that came down with the tree. F 4y ,4 -a , r #9 A large tree that caused slide #10 The slide caused by tree Interflow Release-- This bank wasting is caused by the concentrated release of interflow water onto the bank face (when the temporary perched shallow water table develops at the interface of the top of Till with the bottom of the granular unconsolidated surface soil layer, during 6 the winter wet season). As the water flows onto the bank face, it erodes the unconsolidated surface soil, causing portions of the top of bank to fail. Only minor such wasting was found at this site, as interflow water was observed flowing onto the bank face. Photograph #11 shows how small amounts of surface soil have been eroded away, slowly carving a rounded top edge of the underlying cemented Till. Photo #12 shows a pencil sized stream of released interflow water falling into the post notch carved within the Till bank face (white vertical line just left of post). t aR Y #11 Eroded surface soil, rounded Till #12 Interflow release onto bank No undercutting type Marine Bluff Toe of Bank erosion occurs along the shore of this property, since the beach is higher here. The higher beach is due to the westerly extension of the east-west Till stabilized ridge, with ravines both north and south of it. Photographs #13 and #14 show this higher beach. Ks f . #13 Looking north along shoreline #14 Looking south along higher shoreline 7 2. Site Plan: a. Development Features-- Attachments 2 & 3 show the existing property with the intended locations of the proposed elements, forming the desired new single family residence. The elements include: (i) the existing access driveway; (ii) the Permitted Septic System; (iii) the new water Well; (iv) the new 4-bedroom house; (v) the small retaining walls along the easterly edge of the parking pad adjacent to the garage entrance; (vi) the new stair tower providing beach access; and (vii) the future (Phase 2) 2-bedroom auxiliary dwelling unit. b. Geologic Features-- The existing stable geologic conditions will remain unchanged by the construction of the proposed single family residence as shown upon Attachments 2 & 3. The stabilizing geologic feature is the uniform uninterrupted Hartstine series soil Till formation. Since this property lies upon a small east-west ridge/hogback with no surface water tributary to it, precipitation falling upon the property drains in three directions (west, north & south) as interflow thru the granular surface soil layer. All slopes greater than 15% remain stable since they are underlain by the cemented Till, with no intervening unconsolidated lenses of granular water- bearing soil at elevations above the low tide level. The Marine Bluff Bank is stable, standing near vertical. 3. Soils Examination: a. Exposed Soils-- The primary view, showing the site soils, is the 40-foot high Marine Bluff Bank exposure that forms the westerly edge of the site. The exposed bank face shows the uninterrupted Till soil, allowing the bank face itself to stand near vertical. The following photographs show the exposed bank soil features where minor slides have not obscured them. 8 MW`I �.. #15 Exposed face, low bank #16 Exposed face, high bank Note in both photos, the stable near vertical dense consolidated cemented Till, supporting a thin (24" to 30") unconsolidated granular porous surface soil layer. The southerly site slope (north slope of the southerly ravine) is also exposed, since it has been cleared and a pathway graded into it. The following photos show these exposed soil features: -f Yi i 1 j x Ile- #17 Southerly site slope less than 40% #18 Cut showing thin surface soil 9 The northerly slope on this property is essentially a mirror image of the southerly slope (as shown in Section B-B on Attachment 3), but not as exposed for viewing. b. Test Holes-- Soils test pits were dug on the property as discussed in Section 1 above. These test pits confirm the thin nature of the upper granular soil layer and the underlying Till supporting it. 4. Potential Hazard Discussion: The primary issue, being addressed within this Mason County required Geological Report, is the POTENTIAL HAZARD posed by existing slopes steeper than 15%to 40% (up to 200% at this site). The QUESTION BEING ANSWERED BY THIS REPORT is whether or not these slopes do indeed pose a threat to the Proposed Action. IN SUMMARY, they do not. They are existing steep slopes, maintained stable by the strongly cemented Hartstine series soils Till. All slopes at or near the Proposed Action have remained stable, as evidenced by the review of Stereo Aerial Photos, the age of prior existing nearby stable improvements, examining the recently completed residence constructed upon the property immediately south of the subject property, and the soils investigations reported herein. Furthermore: • No Disturbance of any kind will be made to the stable steep 200% Marine Bluff Bank, located 123' west from the 4-bedroom house footings; • No clearing or grading will occur within 98' from the Toe of the bank, only the clearing of a path to the Stair Tower and the removal of the large trees located at the top of bluff line to relive the threat of Mechanical/Leverage erosion at the top of bank; • No new steep slopes greater than 5-feet in height will be constructed, and these will be protected by retaining walls; • All constructed impervious surfaces will have a formal drainage system to capture and convey runoff to an armored outfall at the beach; • Given the upslope conditions, no new development upslope can change the stability of the existing steep slopes. • No existing down-slope condition will change. a. Location of Potential Hazard-- The worst case Potential Hazard is shown to be the 200% Marine Bluff Bank, running the full length of the westerly edge of the property. Secondarily, slopes less than 40% but greater than 15% exist. The westerly 320-feet of the property (from the top of bank measured east, a distance of 320') have this condition. Within this area, such slopes exist toward the west along the 10 r ridge-line, and both north and south into ravines from the ridge-line. b. Location of Proposed Action-- The Stair Tower will be constructed adjacent to the toe of the 200% bank, at a location where the entire bank face is stable, from top to bottom, and no large trees will exist at its top. The tower will be supported by piles or a reinforced concrete footing, placed on the existing beach. A ramp, approximately 30-feet long, will connect the top of the tower to an anchoring platform constructed 10-feet east of the top of bank. This anchored ramptwalk will be constructed to provide lateral support for the stair tower. The 4-bedroom house will be constructed with its westerly footing located 123- feet east from the toe of the 200% Marine Bluff Bank. A main floor deck will have footings 115' east from the toe. The 2-bedroom ADU is located over 300' east. All other elements of the proposed single family residence, Proposed Action, will be east of the westerly 320-feet area, where slopes are less than 15%. c. Buffer or Setback Requirements-- Given the conclusions from our investigations, we find no reason to impose new buffers or setbacks at this site. The County required setback of 113-feet from the high tide line to the west edge of the 4-bedroom house is plenty sufficient (it locates the house east of a 2:1 slope line from the toe of bank). 5. Elevation Views: Attachment 3 shows the measured Elevation Views (Sections A-A & B-B). Attachment 4 shows the Elevation View of the Stair Tower. These elevation views show the elements of the proposed action located within 300- feet of slopes greater than 15%. Since only two succinct layers of soil exist, within the area represented by these elevation views, the layers were not plotted upon these views. The upper unconsolidated granular porous soil layer is only 24"to 30"thick and is uniform throughout the site The supporting underlying dense consolidated cemented Till is continuous to depths below low tide and uniform throughout the site. 6. Slope Stability Analysis: a. Existing Slopes-- All existing slopes greater than 15%, within at least 300-feet of the Proposed Action, have been determined to be stable. Attachment 7 shows the subject site superimposed upon the Coastal Zone Atlas stability map for this area. It shows that the Marine Bluff Bank face is Unstable, 11 as discussed in Section 1 above. It also delineates the Hb soils as Intermediately Stable and the Ha soils as Stable. Our investigations and analyses have determined that the subject site is stable in both the Intermediate and Stable delineated areas. No slope instability or landslides were found when reviewing Stereo Aerial Photos (6/19181 & 7/30/03). These Photos are presented on Attachment 8, showing a blown-up view of the subject shoreline and property. The primary technical quality governing the stability of these steep slopes, found up to 200%, is the strongly cemented Till formation inherent with the Hartstine series soils that is present in all of the subject slopes (either natural or man- made excavations). This Till was confirmed present in all Potentially Hazardous slopes, except for the upper 24" to 30"thick surface layer which is being held stable, on-site, by good vegetation groundcover. No fill slopes exist and no fill slopes are necessary to implement the Proposed Action.. b. Disturbing Existing Slopes-- All of the Potentially Hazardous slopes occur on- site. If the Proposed Action is approved, no disturbance of the 200% Bluff bank will occur. In fact, we are recommending the removal of all large trees growing on or immediately adjacent to the top of bank line. This will reduce the likelihood of additional Mechanical/Leverage induced bank wasting, which produced the largest of the small slides observed along the adjacent shoreline. Construction of the elements of the Proposed Action, on or near the steep slopes, will involve excavation thru the thin surface soil layer into the underlying stable Till. All footings will be constructed on undisturbed Till. The up-slope ground to the east is less than 15% in steepness, clear to and beyond the drainage sub-basin Ridge line shown on Attachment 5. c. Creating New Slopes-- No new steep slopes will be constructed. The finished westerly end of the access driveway will required cut slopes that will be no higher than 5-feet and will be protected by retaining walls with drains. The daylight basement construction will have cuts protected by concrete walls with drains. d. Calculations-- Since the stability of the Potentially Hazardous steep slopes is governed by the Hartstine series Till soil, no calculations were necessary to support our finding: "that all Potentially Hazardous steep slopes are and have been stable, and will remain stable if the Proposed Action is approved". 12 It is our professional opinion that the use of the "Simplified Bishop's Method of Circles" is not productive with these soils. However, we can evaluate the degree of protection that the 123-foot setback provides by comparing slopes. The setback provides a potential new bank slope of 50% (when drawing a new slope line from the existing toe of slope to the westerly house footing). The existing bank slope is 200%. Therefore, a theoretical existing factor of safety equaling 4.0 can be derived by comparing these two slopes. In terms of Seismic Stability the subject property has remained stable after experiencing over 20 quakes greater than 5.0 during the 42-year Period from 1928 thru 1970, including a 7.1 Olympia quake in 1949 and a 6.5 Tacoma quake in 1965 where significant damages occurred around Puget Sound, such damages worse than those of the 2001 6.8 Nisqually quake (Data from US Earthquakes, USD of Commerce, Coast and Geodetic Survey). 7. Proposed Action Development Placement: a. Drainage-- A new Stormwater Drainage System is necessary, as shown on the Attachment 9 Drainage and Erosion Control Map. It will discharge to an outfall located at beach level with an energy dissipating outlet. b. Septic System-- A new 6-bedroom Septic System design has been prepared and approved for construction. It will accommodate the 4-bedroom house and the 2-bedroom ADU. c. Compacted Fills-- As discussed above, no new fills are necessary or proposed. d. Foundations-- As discussed above, new footings and foundation pads are necessary. All will be constructed upon undisturbed Till. e. Buffers or Setbacks-- As discussed above, no special buffers or setbacks are necessary or desirable, associated with this Proposed Action. All required setbacks are noted on the Site Plan. 8. Clearing and Grading Recommendations: a. Vegetation Removal-- The large trees located near the top of bank should be removed to prevent Mechanical/Leverage bank failure, as discussed above. Clearing of Canopy and Understory, easterly of the Silt Fence shown on Attachment 9, is necessary to construct the 4-bedroom house and finish the access driveway and parking pad. b. Grading Cuts & Fills— Excavation is required easterly of the Silt Fence for the daylight basement, footings, parking pad, driveway, and small retaining walls 13 •diYI�YBYX YIIIYIIrI ... ... -. IIYYIYI �rl�l�0 (shown on Attachment 3). No fills are proposed or necessary. The disposal/spreading of excavated soils onsite is allowable, as long as the soil is not placed upon organic piles of brush or tree limbs etc. or dumped loosely on slopes greater than 15%. c. Revegetation-- Minimal revegetation will be necessary since the areas cleared and graded only encompass areas where the house, driveway and parking pad will be constructed. All remaining Understory vegetation should be maintained. 9. Erosion Control Plan: Since no runoff currently exists and no offsite runoff is tributary to the site, no special erosion control plan is necessary. a. Temporary, During Construction-- A silt fence should be placed, as shown on Attachment 9, prior to the start of construction. It should be maintained until construction is completed and the permanent erosion control measures are established. b. Permanent Erosion Control-- The driveway and parking pad will be covered with several inches of crushed rock.. All ground surfaces, where large portions of bare earth remain (outside the residence and driveway/parking areas), shall be covered with 3" to 4" of loose straw/hay or coarse beauty-bark to prevent erosion. The remaining Understory vegetation should remain undisturbed as much as practical when installing the remaining Single Family Improvements. The roof drain downspouts should be immediately connected to a tight-pipe, armored outfall at the beach level. This drainage system is shown on the Attachment#9 Drainage & Erosion Control Plan Map. 10.On-Site and Off-Site Impacts: a. On-Site— A new single family residence, similar to the neighboring one, will be constructed and maintained on the subject property as shown on the Site Plan. No adverse environmental impact will occur. b. Off-Site-- No adverse environmental impact will occur. 11.Final Proposed Action Development Conditions: a. No disturbance of the 200% Bank steep slope will occur; b. Large trees located near the top of bank line shall be removed; c. The setbacks shown on the Site Plan must be maintained; 14 d. The existing Understory ground cover, outside the designated clearing and grading areas, shall be maintained on all Potentially Hazardous steep slopes. Trimming of brush and thinning out small starter, dead, unstable, or danger trees is allowed, but no bare ground should become exposed. Any resulting bare ground shall be covered with 3" to 4" of loose straw/hay until native vegetation overruns these areas; e. The provisions of this Geotechnical Report shall be followed, unless altered in writing by a qualified professional and any said written alterations are approved by Mason County. 12. Special Mitigation: No special mitigation is necessary associated with this Proposed Action. 13. Final Site Plan Map for Proposed Action: The Attachment 2 Property Layout Map, the Attachment 3 Site Plan, and Stair Tower Elevation View adequately show the existing site and where all elements of the Proposed Action will be located and constructed. Therefore, no additional "Final Site Plan Map" is necessary. Furthermore, Attachments 2, 3, & 4 are sufficient for Mason County to monitor the above presented Final Development Conditions and know when occupancy certificates can be granted. 14.Additional 35mm Photographs Showing Site Features: "r #19 Looking east @ southerly neighbor's #20 Shows no erosion after Dec 09 Rains new House 15 a� #21 Looking west @ Neighbor's stable steps, #22 Looking east @ stable next flight z - t 7. A #23 Top of Bank large tree that should #24 Same situation as #23 be cut, leaving stump. #25 Shows Interflow exiting & flowing down bank face 16 This concludes our Geotechnical Report for the above referenced property. I, Kenneth W. Martig, Jr., PE, of Martig Engineering have completed the required Geotechnical Report as documented within this letter Report and its attachments. I am familiar with this site, having visited and inspected the site and its surrounds. As a result of our investigations, we can affirm that all potential Landslide Hazards can be overcome in such a manner as to prevent harm to property and public health &safety and that no significant Environmental Impacts will result if this Proposed Action is permitted as outlined within this Geotechnical Report and its attachments. CTried by' K eth W. YDpeyrty Attachments: 1ax Parcel Map; '!'�o�W 2Map (1' = 100'); 3- Site Plan Map & Elevation Views (1" = 30'); 170 4- Stair Tower Elevation View (1" = 20'); 0 5- Topographic Map (1" = 500')�; - ° 6- Mason County Soils Map (1 - 500), oMAL 7- Coastal Zone Atlas Map (1" = 500'); 8-Aerial Photo Comparison (1985 vs 2003), tXP ass 1-s- t o 9- Drainage & Erosion Control Map (1" = 40') 17 ATTACHMENT 1 z+ 22 Limerick Vicinity Map, and �L .. I ae W i— ------� Tax Parcel Map _ u�g` ,.PA S " „n A$cc 1 �+0 + �& Cranberry ' + _ ?J% �zs l 30 �"" 2eQ A� z ;i Loke � -Way t o — - 2=s4- / �- 32 •Imp 0� -- C.onlfe .ate F Spence �,rw 'N �Of C 1 t� tl71 A _7 35 ONias Rtl PAR4LLE I Z ry nBlvd t +, D ORTH 1 ✓ah�s Gr Boy Shore' P� sw.imeoiey t� $ GrantJ," y Waa+e` 1 RQ 1 Man Oc 6 e p& Mott tn. e G Pnr//ips Lake tianstene: wry Law Rd- t� --t &ageRd .: .eilftone Cnloe fa i' ,apP +2 Lg VC t— Ooklond 3 6 i BertalsenRd I h !1� Eit -ChoDma+ '-'t L4-- � cove } oD Rd Vicinity Map SECTION 34 I . 1290020 SP 1530 1101 1101 1101 1101 129Ql40 12000lO 040 030 020 000 `Y1 1101010 i _-- 1200060 `1 rGT G 1200 1200080 A)ioo t 000 291051 991052 891053 1 91054 1200070 S I30 or-1i 7�7-8 sf c,L. r 1883 d 527R +i `t192o I ,172 S 2066 BLA 93-97 1920 1920 1290100 t 290030 5- 03 04 1102030 1290150 1290160 1250170 192 2 524-112 t St - 1290040 1102010 12so 130 sf:✓y_ S1 13741 290 1 20 ——— 1102020 1290050 1290110 S 23/05 7690025 SPI 194Z S 14/W6 T SP 586 10/93 7590 7590 7590 7590 7690024 7690 9001 � Olt �_ 012 013 SP 1345 o1 c4 P2937 7690021y�/.y o P1343 90016y S l6/179 7690022 7690 7690 17690 013 012 Oil 7590022 7690023 7590021 75 90024 c r N \ 75 90023 1300000 \ of 1300011 S 12166 \�i —-- 1300010 \ 7500030 S /t1794 a ®w s $ ♦ .� .a r Q dpo cpk � h i . a r b. Oi \ w 1 \ S o , lh ,� XN At \ � V c♦ �`� D CL CM _ ',♦ �'' C � O o L`s•`� s• Q s ' yy V� $✓�>s ter. L. u�.a c . O � m 00 c� 0 no 77 mul 3 d Q, � t!! � 01; � � �. �_ 3 f1 -► 1p - " \o I ' Q S r t � 3; \ � a ( � W 6 � W e Q` S,S < � s o N LI Cd ADO 4. r4 � O ,14o q M O s / Vv �. Ir 6 of : •J + °r y ! i \ ci r V+ ! n or I \ s D N 1 o ES � Q-o •yi d i Q 'C ash 4 04 v L a o I� Z ATTACHMENT 4 Stair Tower Elevation View (1" = 20') 7o.,�etir TOP �30�Lov5 Qa"nP� TU (� (,o ��acEc Curbiv.9 �y`�or Pt��OrYri 16" f4.• 40► 4115k o.5 � Rv�V�"cor� GoenC.. Tower , �`� ,C� niJ�" Bea-c)^ Towev' o ( S F•Q�� �„Oo�G.tti� �9YT-�� I t Legend 1. Floor Laval Platform 2. Non-Load Bming Building Attachment 3• Support Column 4, _ 4. Exterior Guard Rail -- S. Inwricw Guard Rail �- 6. Horizontal Tuba . tatermaliatc Plstfa= 8. Stringas 9. Non-Slip Aluminum Dock Plate iQ.Nan-Slip Aluminum Tread 1L 11. Concrete Base 12. Column Attachment to Base 4 ` ATTACHMENT 5 ''R• Topography Map 4 '"' '��• USGS Mason Lake Quad. �.: (1" = 500') )af ' ;'1K `•ty Z S 1� e m e 2 i 1 t- f:. , i�. R 4 1 a� .�, ■ si .ti-. rs••' �..t .* WT ..�,. s4 i? ■ r: ATTACHMENT 6 Mason County Soils Map �. ,. (1f, = 500') Ha k 1� b 34 I b � . ........... 1 i m-wwfikv*w. ' ATTACHMENT 7 Coastal Zone Atlas �I Bluff BankF'S�1tabilit} F AI�^y 7 y (1 [f 5001) i !23/ AOL �� � � s'i• 9ra1-� gpyt�,.�+r44.a.,•:na► - - � it 'rsi1M#h-1fIR 1cMN:,K••►�11.==r7.'.!� 7 � _ '� � 1 t. N/rE+✓ art:..�..:..1 — �r•1:3�fi.. a �rt • rt ' a i � �} ',' {•�h „'r''� sir �-� �F If 79 ..t .. �Tir+iY� _ _ .. • ram• .�. �� _ j AD, R Jr l' 0 Q. cc it I C) Q— 02 UJ 0) Ck X, Oil o (J C) 0 -,Y LL C� 1�11 (�AL "•� Mason County Department of Community Development Submittal Checklist For a Geotechnical Resort Instructions: This checklist must be submitted with a.Geotechnical Report and completed,signed,and stamped by the licensed professionals)who prepared the Geotechnical Report for review by Mason County pursuant to the Mason County Resource Ordinance. If an item found to be not applicable,the report should explain the basis for the conclusion. Applicant(Owner ft '+t-1 5 C Parcel#_ 2 Z..)34 12— 4 O04-V Site Address 10 3 D IF, SNhS t�- ai( I IZJ,.. .S"I 1* WA I >S$L4. (1) (a)A discussion of generaLge6logic conditions in the vicinity of the proposed development, Located on page(s)_ Soc. I a (b) A discussion of specific soil types Located on page(s) 3r Soc. lip S A t*&-e- ..ts, & r fo (Sec-3 as% (c) A discussion of ground water conditions P«So t Located on page(s) 4 Stc 1--c- (d) A discussion of the upsio a geomorphology l s �, Located on page(s) 5 S o< t.4. g A�s.�.�,,.a�...'! (e) A discussion of the location of upland waterbodies and wetlands Located on page(s) S' S lqc ld N!b'h e E -* (f) A discussion of history of landslide activity in the activity in the vicinity, as available in the referenced maps and records Located on page(s) ,S_ !o .*.S.e�. 1 9 A44oLr + v-u4$ "7 E It ---� -. (2) A site plan which identifies the"imporfant developmentand geologic features. Located on Maps) A � (3) Locations and logs of exploratory h les or probes. Located on Map(s)�t ae L LAL 1ft k z- (5 ec 31, o h P43t 10 (4) The area of the proposed development, the boundaries of the hakard, and associated buffers and setbacks shall be delineated top, bo th sidwes,and toe)on a geologic map"of site. Located on Map(s) �.1�a c fir. Z C. 3 t, 5 *V% F&L t o (5) A minimum of one cross section at a scale which adequately depicts the subsurface profile, and which incorporates the details,of proposed grad changes. Located on Maps) Aj4e.al ►y.44..�3 3 ;f,4- (,SeC o 1.. Iayt 1 1 (6) A description and'results of slope stability analyses perlbr ned;for both static and seismic loading conditions.Analysis should examine worst case failures.The anafj Is should include the Simplified Bishop's Method of Circles.The minimum static safety factor Is 1.5,the minimum seismic safety factor is 1.1. and the quasi-static analysis coeffignts shoyjd be a value of 0.15. Located on page(s) S« G o k �a1 t 5 ) 1 r lZ 4 13 t (7) (a)Appropriate restrictions on placement of drainage features Located on page(s) S o.c. -1 •4. ➢«wd 13 r k4'A o.(,%t,,,�, (b) Appropriate restrictions on placement of septic d 'n fields 1 Located on pages) /t1.1-��c.L, -ah-�- Z, LIN r�v ea S�t�J�-1 c o c.�"plop (c) Appropriate restrictions on placement of comp cted fiJJs and footings Located on page(s) So C 7 d o k ��t 3 " A tr{o.a�.�w•. ,,�,� 3 Page 1 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnical Report. ;4 (d) Recommended buffers from the landslide hazard areas shoreline Nuffs and the tops of other slopes on the property. Located on page(s) Sec- ?! e+, 'Pw&yt 13 A R4Gt tiv�s�•. 3 (e) Recommended setbacks from the landslide hazard areas shoreline bluffs and the tops of other slopes on the property. Located on page(s) Sec Z .ti. pi7t 1 3 A, V}a c,&v+a (8) Recommendations for the preparation of a detailed clearing and grading plan which specifically identifies vegetation to be removed,a schedule for vegetation removal and replanting, and the method of vegetation removal. Located on page(s) S*c. S « 10% 1?#—*es 13 c )4� ��}acla,,.s,..r�- 3 L 47 (9) Recommendations for the preparation of a detailed temporary erosion control plan which identifies the specific mitigating measures to be implemented during construction to protect the slope from erosion, landslides and harmful construction methods. Located on page(s) S tc ') •r. 1'•%Zt 14-04 Qr 4 a c L,&-V (10) An analysis of both on-site and off-site impacts 91 the proposed development. Located on page(s) S ac 10 w r, rP65 a. 14. (11) Specifications of final development conditions such as, vegetative management, drainage, erosion control, and buffer widths. Located on page(s). S Cc- 1 o h IP«'$eS (12) Recommendations for the preparation of structural mitigation or details of other proposed mitigation. Located on page(s) I�a.5 G 1 yr (13) A site map drawn to scale showing the property.boundaries,scale,.north arrow, and the location , and nature of existing and proposed develo ment on the site. Located on Maps) A.t4-r^c L%h-&t-% Z , 3 °! i, hereby certify under penalty of perjury that 1 am a civil engineer licensed in the State of Washington with specialized knowledge of geotechnicaUgeologicai engineering or a geologist or engineering geologis'.t licensed in the State of Washington with special knowledge of the local conditions. I also certify that the Geotechnleal Report,dated D ,and entitled Co&w d2 h ai;..c t �!' 1i^d► t�'�. S c,�,.e�a, - meets all the requirements of the Mason County Resource Ordinance, Landslide Hazard Section,is complete-and trye,that-thefassessment demonstrates conclusively that the risks posed by the landslide hazard ca�Itlgated be mitigated through the included geotechnical design recommendations, and that allthazards are in1such-a-manner a to prevent harm to property and public health and safety.(Signature=and'Stamp) AO a SPIRES 1-4- 0 1 Page 2 of 2 Form Effective June 2008 Disclaimer: Mason County does not certify the quality of the work done in this Geotechnicai Report. I (8/13/2008 Grace Miller- Re:Thanks, Mar ie Pa e 1 From: "Schirato, Margie(DFW)"<schirmms@dfw.wa.gov> To: <Gbm@co.mason.wa.us> Date: 8/13/2008 11:14 AM Subject: Re: Thanks, Margie Sure that will help keep it clean >>>Grace Miller 08/13/08 11:06 AM >>> Thank you. I noticed we have this standard condition for building permits that we can add and is it current? I am wondering if we should be adding it? "All new treated piling to be used for this project shall receive a post treated vacuum of two hours at not less than 22 inches of mercury.Subsequent to release of the vacuum,the piling shall be steamed for a two hour period, followed by a second vacuum of four hours at 22 inches of mercury." (8�13% 08 Grace Miller- Re: Pilin s Pa a 1 ; From: "Margie Schirato"<schirmms@DFW.WA.GOV> To: <Gbm@co.mason.wa.us>, <mkholten@comcast.net> Date: 8/13/2008 10:25 AM Subject: Re: Pilings Treated wood may be used as long as it is not creosote treated. I would suggest a wood pile with a prefab concrete base similar to the types used for upland decks to avoid contact with the water as much as possible. Concrete will last longer than wood. >>>"Holten"<mkholten@comcast.net>07/28/08 8:51 AM >>> Hi Grace: I hope you had a nice vacation. I have some qustions about pilings for our stair tower. Costwise, it looks like we may have to go with our original four-pole tower configuration. If we go with wood poles buried in the beach, can they be treated? If so, what treament options are permitted?(I have seen reference to ACZA pilings.) Thank you again for your assistance. Mike Holten (7/28/2008)Grace Miller Pilin s _ �� . _ --� Page 1 From: "Holten"<mkholten@comcast.net> To: "Grace Miller'<Gbm@co.mason.wa.us> 4vv p&-Oor Date: 7/28/2008 7:56 AM Subject: Pilings Hi Grace: I hope you had a nice vacation. I have some qustions about pilings for our stair tower. Costwise, it looks like we may have to go with our original four-pole tower configuration. If we go with wood poles buried in the beach, can they be treated? If so,what treament options are permitted? (I have seen reference to ACZA pilings.) Thank you again for your assistance. Mike Holten lot, e7 - - ` �rt•rtiv�o� (fin•.�01 Wti.v f cN-�,..,,..._ �J-I-L.,,,,, �o � � 41, rtct >-(-A# w MASON COUNTY Shelton (360)427-9670 DEPARTMENT OF COMMUNITY DEVELOPMENT Planning Belfair (360) 275-4467 Mason county Bldg.i 411 N.5th Elma (360) 482-5269 P.O.Box 279 Shelton,WA 98584 TO: THE MASON COUNTY JOURNAL FROM: MASON CO. DEPARTMENT OF COMMUNITY DEVELOPMENT DATE: ��(p Lp q Please publish the attached1. �n the following day(s) t , o0 9 ad pq a-00 q Please keep the Affidavit of Publication for the Department of Community Development to pick up from your office and send_�copies to the following Ar- WA q$37y Please charge j6 ,,,, dave- for the publication at: Thank you, Mason County Planning Staff 02/06/2009 17:38 FAX (a 001 x TX REPORT sus TRANSMISSION OR TX/RX NO 0447 CONNECTION TEL 94269399 SUBADDRESS CONNECTION ID ST. TIME 02/06 17:37 USAGE T 00'58 PGS. SENT 4 RESULT OR i MASON BOUNTY ( PLANNING DEPARTMENT FAX. Pirane:(360)4.27-9670 ext. 7U Fax:(36014-27-8426 + TO t COMPANY NAME: 1J 'L. r` CONTACT NAME: FAX NUMBER: PHONE NUMBER: ..REGARDING: � FEB-26-2009 THU 10:22 AM FAX NO. P. 02/02 FrnrE o� o JAN� STATE OF WASHINGTON DEPARTMENT OF ECOLOGY p0 Box 47775 • Olympia,Washing ton 98504-777.5 • (360)407-6300 February 26,2009 Ms.Grace Miller r Your address Mason county is 1n.the Department of community Development Kennedy- Planning Division Goldsborough PO Box 279 watershed Shelton,WA 9SS84 Dear Ms. Miller: Thank you for the opportunity to comment on the mitigated determination of nonsignificance for the Schaaf Stair Tower project(SEP2009-00003)located at 1030 East Sunset Hill Road in Shelton as proposed by Judith Schaaf. The Department of Ecology(Ecology) reviewed the environmental checklist and has the following comment(s): SHOREtANDS&ENVIRONMENTAL ASSISTANCE: Kim Van Zwalenburg(360)407-6520 Stair towers are significant structures on the landscape and the cumulative effect of these along a shoreline might-have substantial adverse effects on the shoreline environment. Like piers and docks,opportunities should be explored for joint use of these sorts of beach access structures. In addition,these sorts of structures should be considered sacrificial--In other words, bank stabilization structures(in the future)to protect a stair tower would generally not be allowed. Ecology's comments are based upon information provided by the lead agency. As such,they may not constitute an exhaustive list of the various authorizations that must be obtained or legal requirements that must be fulfilled in order to carry out the proposed action. If you have any questions or would like to respond to these comments, please contact the appropriate reviewing staff listed above. Department of Ecology Southwest Regional Office (SM:09-0581) cc: Kim Van Zwalenburg,SEA Judith Schaaf(Proponent) Kristin Holton(Contact) i��1 FEB-26-2009 THU 10:22 AM FAX NO. P. 01/02 FAX NUM13ER QQ� - FAX COVER SHEET DATE: D :Lq TIME: # OF PAGES f 4-0w4-e"" FROM: � REMARKS: Washington Department Of Ecology Southwest Regional Office 300 Desmond Drive SE ` P.O. Box 47775 ' Olympia,WA 98504-7775 Phone: (360) 407-6300 " FAX: (3,60) 407-6305, THE SHORELINE PERMIT PROCESS— Page 5 LIST OF ADJACENT PROPERTY OWNERS WITHIN 300 FEET OF YOUR PROPERTY BOUNDARIES FOR CONDITIONAL USE AND VARIANCE Addresses may be obtained from the Mason County Assessor's Office, Building 1, Second Floor. GWL CORPORATION ? MYRON F H nTINGER 1 ZRAY&JANA HOCKER P O BOX 1671 41 E SUNSET BEACH DR P O BOX 477 VISTA,CA 92085-1671 SHELTON,WA 98584-7070 FALL CITY,WA 98024-0477 NEIL&NANCY MCREYNOLDS GWEN THORSOS AN&NILSA THORSOS 14312 SE 45TH ST 860 E SUNSET HILL RD 854 CAVANAGH RD BELLEVUE,WA 98006-2349 SHELTON,WA 98584-9443 GLENDALE,CA 91207-1502 KRIS&DEBORAH THORSOS q APRIL&DAVID HANSEN AUL DOBOSZ LJ 313 BUTTE PL 961 E SUNSET HILL RD 1011 E SUNSET HILL RD PACIFIC,WA 98047-1480 SHELTON,WA 98584-8476 SHELTON,WA 985844444 /y DAVID POTWIN KAREN HOLT Y&CANDACE WARKENnN 4337180TH IN SW 3032 SAPP RD SW 11209 SANDY GROVE AVE ROCHESTER,WA 98579-9433 OLYWIA,WA 98512-6753 LAS VEGAS,NV 89134-1841 SCOTT HOWARD TED WAITERS AyR 1CAui": C5� 7125 34TH AVE SW PO BOX 281 5CkaaF SEATTLE,WA 98126-3301 ENTIAT,WA 98822-0281 i! as 1a&+-Ai/e CT 6 WA IS3 4 ,1FF1.tCAkrl 45 i2& ,M�tC.(�+IG-t45nA3 Hz LTPN }�w� WA 9 83?q