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HomeMy WebLinkAboutCritical Area Buffers - GRD Engineering / Geo-Tech Reports - 12/2/2004 r MASON COUNTY �LF s u° PUBLIC WORKS DIRECTOR/COUNTY ROAD ENGINEER Q T Shelton,Washington 98584 Ny DATE: December 2°d, 2004 INTER-DEPARTMENTAL COMMUNICATIONS TO: Diane Marcus Jones, DCD—Planner Kristen French, DCD - Planner FROM: Alan A. Tahja, P/W - Co. Hydr. Engr. WO#PLG-04 SUBJ: Enforcement Case Review NAME: Vermillion Grading_na, S Shr Rd ENF2004-00126 The geotechnical report/restoration plan prepared for the Jerry Vermillion property located on the south side of the South Shore Road(State Highway 106)has been received and reviewed by Public Works. The materials submitted for Public Works review included a preliminary geotechnical report prepared in 2002, and a more recent completion of that original report, dated March 30, 2004. The most recent report indicates that the proposed project consists of"leaving in place, as is, the existing Cleared Areas and system of Trails/Roads on his property to provide access throughout his property for fire protection and select tree cutting. Further, he proposes to maintain them, do select tree cutting, and occasionally install spur skid trails to access select trees." The report may be considered adequate based on this level of activity, and provided the engineer's recommendations are incorporated into the limited activities indicated in the report. The roads already constructed on the Vermillion property, are viewed as temporary logging roads with no permanent status. If in the future, the property owner renews his plans to develop the property into divided lots, claims that any roads already exist will not be entertained when stormwater modeling of the site is performed. To summarize,the report appears adequate for the proposed continuance/maintenance of the logging access roads, but the reviewed plan is not detailed enough to allow additional un- permitted grading or clearing. Please feel free to contact me at County extension 461 if you have any questions pertaining to these comments, or if you feel additional features or issues need further attention. Since 1y, � � l Wan A. Tahja File: H: \WP\GEO\Restoration Plans\Ve=illion.doc MARTIG ENGINEERING P.O. Box 11850 Olympia, WA 98508-1850 (360) 754-9687 Fax (360) 704-0789 RECEIVED March 30, 2004 APR 0 7 2004 MCCD - PLANNING Mason County Department of Community Development 426 W. Cedar P.O. Box 578 Shelton, WA 98584 Attn: Kristin French, Code Enforcement Re: GEO-TECHNICAL REPORT for: * Property Owner- Jerry Vermillion * Parcel Address- 8371 E. Hwy 106 Union, WA 98592 * Phone Number- (360) 898-8234 * Tax Parcel Numbers- #32234-44-00010 & #32234-44-00000 * Proposed Project- Leave in-place, as-is, existing Cleared Areas &Trail/Road System-, Maintain same-, Cut select trees-, & Install occasional spur skid trails * Response to Mason County Code Enforcement requirement to provide submittal of FULL GEO-TECHNICAL REPORT. Dear Ms. French: Martig Engineering has completed a full Geo-Technical Report for the above referenced Vermilion Property/Project, to satisfy Code Enforcement requirements. As a result of our investigations, outlined within this Report, we can affirm that all potential Landslide Hazards can be overcome in such a manner as to prevent harm to property and no significant Environmental Impacts will result if this project is permitted as outlined within this Report and its attachments. PROPOSED PROJECT Jerry Vermillion proposes to leave in place, as is, the existing Cleared Areas and system of Trails/Roads on his property to provide access throughout his property for fire protection and select tree cutting. Further, he proposes to maintain them, do select 1 tree cutting, and occasionally install spur skid trails to access select trees. The Vicinity Map (Attachment # 1) shows directions to the property. This Vermillion property has two Parcel Numbers. On July 26, 2002, a Geo-Technical Report was prepared for Parcel # 32234-44-00000 for the Building Permit involving the construction of improvements to his existing single family residence. A copy of it is attached to this Report as Attachment # IV. On November 11, 2002, an Engineering Report was prepared, as a precursor to this Geo-Technical Report, to present the current status of Trails/Roads and Tree Cutting that had been conducted before County approval to do so. A copy of it is attached to this Report as Attachment # V. The following discussion summarizes our: Site Investigations; Research of Site Conditions; Analyses; and Conclusions, allowing this Geo-Technical Report to be completed for the above referenced site. GEO-TECHNICAL REPORT 1 . Geology, Soils, Groundwater, Landslides.- This site is shown on the Mason County Coastal Atlas Maps (Attach. #5 & #6 within Attachment # IV ). Attach. #5 shows the residence located within a Stable designation, with the adjacent land to the south (Parcel # 32234-44-00010) being designated Intermediate. No landslides are designated near this site. A small perennial Spring emerges from the hillside in the northwest portion of Parcel # 32234-44-00010 at an elevation of approximately 45. It creates a Type IV Stream that runs across both parcels. Very small, localized, extremely minor, surface slides have occurred near the spring. These minor surface slides cause localized shifting of the stream channel but do not create structural instability of the hillside. Attach. #6 shows that the Parcel # 32234-44-00000 site soils are an Alluvium of sands and gravels which allow moderate infiltration and low runoff. The adjacent Parcel # 32234-44-00010 soils to the south are Pleistocene gravel deposits older than Vashon Till which stand at steep natural slopes for long times with high infiltration and low runoff. The Mason County Soils Survey identifies the Parcel # 32234-44-00000 site soils as Everett Gravelly, Sandy, Loam and indicates slopes of 5 to 15% (measured to be in the 5% range at the existing residence). These soils are well draining and consistent with the Geologic Conditions reported in the Atlas. The adjacent Parcel # 2 32234-44-00010 soils to the south are shown to be Alderwood Gravelly, Sandy, Loam with slopes 30 to 45%, found to be as high as 59.6% on the Union Quadrangle Map. We found no evidence of slides or slope instability during our site inspection visits nor did we find any using DNR stereo Aerial Photographs dated 1989, 1995, 1997, & 1999. A 1" = 500' scale copy of the 1999 DNR Photo (Attach: #7, within Attachment # IV) shows the stable site. The south Highway 106 ditch captures both surface water runoff and shallow groundwater interflow and conveys them to the Canal easterly of the residence. Only the precipitation falling directly on Parcel # 32234-44-00010 introduces water into the site soils. Since the surface rapidly infiltrates precipitation, very little surface water flow can exist. The southerly property line of Parcel # 32234-44-00010 lies at the ridge of the watershed, therefore, no off-site water is tributary to the property Given the geologic conditions, we did not expect to find, nor did our site inspection encounter, any horizontal subsurface groundwater interflow thru unconsolidated soils that could cause slope instability on either parcel. No new clearing or measurable new grading will occur. The existing cleared areas and the existing Trails/Roads will be maintained as such. DNR road water baring will be used to prevent the development of down-gradient road erosion/washing. Attachment # V shows photographs of the major portions of existing cleared areas and Trails/Roads. No new roads will be constructed without prior County approval. Small spur skid trails can be allowed, to reach selected trees from existing Trails/Roads, without causing any hillside instability or any adverse environmental impact. The selective removal of trees can be allowed without causing any hillside instability or any adverse environmental impact. 2. Site Plan of Important Geologic Features: The Vicinity Map, Attachment # I shows the Vermillion Property on the USGS Union Quad Map at a scale of 1" = 500'. It shows that the major release of water from the hillside occurs within streams located westerly and easterly of the property A minor swale runs along the westerly property boundary but does not support a stream. The small perennial spring located in the northwest corner of Parcel # 32234-44- 00010 is located just east of this swale but has had no major impact on the hillside contours. 3 Attachment # II shows the USGS Quad contours at a scale of 1" = 200'. Both property parcels are shown on it, along with the location of two Elevation Views (Attachment # III shows these elevation views as Section A-A & Section B-B). You can see the stable, uniform spacing of the 20-foot contours and see that essentially no off-site water is tributary to the property. 3. Location of Soil Exploration Holes/Probes: The above described soils formations that exists at and near the site are exposed as cut-slopes along older logging road grades existing within Parcel # 32234-44- 00010 (photographs of these appear in Attachment # V). Additionally, previously dug septic system soils test pits remain at various locations along the hillside, confirming the reported soils. Given these exposed soils, no additional soils test borings or test pits were required to confirm the conditions and type of the site soils. 4. Cross Sections showing slope disturbances: No new excavations or grading will occur. The existing cleared areas and Trails/Roads have been monitored for stability since early 2002, which includes the winters of 2002/2003 & 2003/2004. These existing improvements have remained stable with no required maintenance. Cutting and mowing will be necessary to keep the vegetation growing within these existing improvements at ground level to facilitate travel over them. No side-slope disturbances will occur. Section A-A & Section B-B, shown on Attachment # III, are the two Elevation Views drawn on the Attachment # II USGS Quad Topographic Map. They show that the predominant hillside slope varies from about 30% to 60%. However, localized small areas of lesser slopes occur at several locations within Parcel # 32234-44-00010, especially along the south Hwy 106 righ-of-way. 5. Slope Stability Discussions.- As discussed within this report, the existing Cleared Areas and Trails/Roads are stable and are not creating landslides or other adverse environmental impacts. Leaving them as constructed, the proposed maintenance of them, the proposed cutting of selected trees, and the installation of spur skid trails to reach some selected trees will not create significant environmental impacts and no landslide hazard will be induced if these proposed activities are permitted. 6. Drainage, Septics, Water, Placement: This Geo-Technical Report addresses leaving in place the existing Cleared Areas and Trails/Roads as well as the continued maintenance of them. It further addresses the selective cutting of trees and the installation of spur skid trails as 4 approvable activities. Therefore, no Septic or Potable Water issues are relevant. Improvements associated with the older existing residence on Parcel # 32234-44- 00000 and related water & septic issues were addressed in the July 26, 2002 Geo- Tech Report, Attachment IV. No runoff problem exists at either parcel. The site soils infiltrate very rapidly once the good existing Understory vegetation becomes completely wetted. The site has been monitored for runoff problems over the last two winters. 7. Clearing & Grading Plan: No new clearing or grading is proposed, only the maintenance of existing Cleared Areas and Trails/Roads, the select cutting of trees, and the occasional installation of spur skid trails to access selected trees. 8. Erosion Control Plan: Since no new grading will occur, special erosion control measures will not be needed. The existing Clearings and Trails/Roads will remain intact. These areas are stable with existing water bars and natural vegetation. Trail/Road maintenance involves the blading/cutting and/or mowing of vegetation growing within their existing limits to allow travel over them. Water bars will be maintained and added if traction ruts develop. Select tree cutting must leave the Understory vegetation intact. Any newly exposed bare soil resulting from the installation of occasional spur skid trails must be immediately covered with 3-inches of loose straw/hay until natural vegetation returns. Water baring and/or other DNR erosion control measures should be used if/as required. 9. On-Site & Off-Site Impacts: In summary, no adverse environmental impacts nor landslide triggers will result, either On-Site or Off-Site, if the existing Clearings and Trails/Roads are allowed to remain as constructed. Nor will their maintenance, the select cutting of trees, and the occasional installation of spur skid trails, if these activities are permitted as presented within this Geo-Technical Report. 10. Final development Conditions: Existing site conditions will be maintained and no new clearing or grading is necessary. Therefore, no special conditions are necessary for this Project as proposed. 5 I, Kenneth W. Martig, Jr., PE, of Martig Engineering have completed the required Geo- Technical Report as document within this letter Report and its attachments. I am familiar with this site, having lived in the area for decades and having visited and inspected the site and its surrounds for several years and the two most recent winters. As documented, potential landslide hazards have been overcome and no significant environmental impacts will result if this proposal is permitted as discussed above. C ified by: K nneth W. Martig, r., E Attachments.- #1 Vicinity Map and Site Entrance Photo; #11 USGS Union Quad Topography Map (with two Elev. Views); #III Elevation Views Drawing, Section A-A & Section B-B; #IV Parcel # 32234-44-00000 Geo-Tech Report (copy); & #V Parcel # 32234-44-00010 Engineering Report (copy). GIs ON ENO EXPIRES 1-9- O 6 flit t + 'L feed Ca�...1 00, -1 VIClNrrY MAP NOT M SCALE 1- 0 w+r rl� 1 00Z=1.1 " Y o00o— ON --j A va X-aJ, �y,o) 4 Y1j "�MRsjR�i's' ° ri � N�s'Ea ��is�rld+M.r�s're`�. s ;+` � tp° <'Srex. •s;st�far�',�,# CI.38 0 SHEE t EYE,E SE 5 J}�UAnp •I , ` d2�e1 SOSMEEt$EYE-EASE SSOUAAE MNaBona!'"BnM a?349 ?O0O SHEETS Eve-F�s SUOUARE y0.CL,V. m SOO �leva�inc. J�e�S se.CA-to* " A-A. i 4. 0 p SGC, oL'O /� -A S. = 4s ^ 3v0 -Loo I-- i l0O Se�i-6oh 5 — Idti _ 59.6�0 z3s 0 D loo Zoo 300 4-00 SOD a 100 zoo pt1 ,- Gct lS� U MASON COUNTY 4,0 NkL"' DEPARTMENT OF COMMUNITY DEVELOPMENT Planning Mason County Bldg.1 411 N.5th ( � — P.O.Box 279 Shelton,WA 98584 (360) 427-9670 Belfair(360) 275-4467 Elma (360) 482-5269 Seattle (206) 464-6968 November 18, 2002 Jerry Vermillion c/o Ken Martig Martig Engineering P.O. Box 11850 Olympia, WA 98508-1850 RE: Engineering Report; Tax Parcel Number 32234-44-00010 Dear Ken: I received the Engineering Report that you prepared, addressing the grading activity and vegetation removal that occurred on the above noted parcel. While the Engineering Report does not co ntain ontain the information required in a formal Geotechnical Assessment or Geotechnical Report(pursuant to Mason County Resource Ordinance section 17.01.100), I understand that the Engineering Report was submitted to address the County's immediate concerns while a formal Geotechnical Report is prepared for the site. The Engineering Report has not been reviewed or approved by Mason County's Engineer. Rather, I have accepted the Engineering Report as an interim compliance measure pending receipt of the formal Geotechnical Report. From the Engineering Report, I understand that you prescribe no additional erosion control actions at this time. I understand that you(Martig Engineering)will monitor the site through the 2002-2003 winter wet season, and will immediately coordinate corrective measures with Mr. Vermillion if any potential problems become evident. Finally, I understand that no new grading or vegetation removal will occur until a full Geotechnical Report supporting such additional activity is submitted to, and approved by Mason County. You mention that"removal of firewood and timber thinning will continue, using existing roads that will be maintained using DNR BMP's to arrest runoff and erosion." I would like to reiterate that any land clearing performed contrary to Mason County Resource Ordinance section 17.01.100 will be pursued as a willful violation of County regulations. I have enclosed section 17.01.100 for your review. Please discuss the section with Mr. Vermillion, and contact me at (360)427-9670 ext. 593 if you have any questions or concerns. i I anticipate working cooperatively with you both, and thank you for your attention to this matter. At this time, I will place the enforcement file on"hold"status,pending receipt of the formal geotechnical report. Upon receipt of an acceptable geotechnical report for the parcel, the enforcement file will be closed. Regardless of whether Mr. Vermillion ultimately decides to go ahead with his development proposal for the parcel, an acceptable geotechnical report addressing at least the work performed to date must be submitted. The geotechnical report must be submitted to satisfy requirements pursuant to Mason County Resource Ordinance section 17.01.100, and resolution of this enforcement action is contingent upon submittal of an acceptable report. Mason County has jurisdiction over this matter until October 26, 2003. As such,the report must be submitted by August 26, 2003 to provide the County the opportunity to review the report and schedule a compliance hearing if necessary. Again, thank you for your anticipated cooperation. Sincerely, Kristin French Code Enforcement Cc: Michael MacSems 1 MARTIG ENGINEERING P.O. Box 11850 lt�2o�Z Olympia, WA 98508-1850 (360) 754-9687 �„J eav'-e.t November 11, 2002 Mason County Department of Community Development 426 W. Cedar P.O. Box 578 Shelton, WA 98584 Attn: Kristin French, Code Enforcement Re: CODE COMPLIANCE for: * Property Owner- Jerry Vermillian (10237 Kiwa Dr. SE, Olympia, WA, 98513); * Parcel Address- 8371 SR 106 Union, WA 98592; *Phone Number- (360) 491-8234; *Tax Parcel Number-#32234-44-00010; *Completed Grading- Access Roads & Graded Pads/Turnarounds/Staging Sites; *Response to Mason County Letter- Code Enforcement Warning Notice, 2/15/02; *SUBMITTAL OF ENGINEERING REPORT; *Supplement to existing Correspondence; Dear MS. French: This Engineering Report documents our investigations and analyses of the above referenced property in response to your Warning Notice Letter dated 2/15/02, our site visit with you and Michael MacSems, and numerous discussions concerning the grading activity and vegetation removal that has occurred on this property. This Engineering Report is intended to address the stability of the already graded areas of concern and will be followed, at a later date, by a full Geotechnical Report. The full Geotechnical Report will cover how the already graded areas will be integrated into an approvable development plan, or restored, as well as cover all other necessary elements of the proposed development plan. 1 SITE INVESTIGATION On October 8, 2002, Martig Engineering conducted a complete inspection of all areas on the above referenced property where grading and vegetation removal has occurred. When comparing the graded areas with aerial photographs of record, we find that this grading has been ongoing over a number of years. Originally, grading of logging roads and skid trails was conducted to remove timber. Also early on, graded access to a potable water supply spring was conducted, with water supply pipes being installed to deliver water to cabins on the Canal. While in control of the property, Mr. Vermillian has improved and extended the logging roads and skid trails to further remove timber and firewood. Associated with this activity, he has graded level pads for decking logs, sawing lumber, and producing split fi rewood. Recently, Mr. Vermillian has been attempting to sub-divide the property into several single-family residential lots. He did contact Mason County staff during his efforts, and did proceed with Septic System perk holes (which required additional access grading). However, he did not understand the actual process requirements, since many of the applicable regulations were evolving and new to him. Mr. Vermillian completely halted all grading and vegetation removal since receiving the February 15, 2002 Warning Notice letter. His activities have been restricted to cutting firewood and finishing the sawing of lumber, both using roads and sites existing as of 2/15/02. During our site investigation we photographed all areas where grading and vegetation removal has occurred. Attached at the end of this Report narrative is a copy of the "Roads & Grading Site Plan, Photo Inspection Record". This Site Plan shows all graded areas and where each of the thirty-one photographs was taken. Copies of the photographs are also attached. ANALYSES As shown in the attached thirty-one photographs, most of the graded areas have noticeable vegetation on them, except the tire tracts where bare gravely soil remains. This vegetation consists of planted grasses and natural Understory brushes, weeds, vines etc. and Canopy seedlings of Alder, Fir, Cedar, etc. that have started naturally. 2 Photographs 1 and 2 show the road associated with the Septic Drainfield for the Vermillian Cabin. This road continues up the hill for timber and firewood removal as shown in photos 3 thru 6. Photographs 7 thru 15 show the majority of the roadway grading. Potential building sites, yet to be proven feasible, exist at photo site 7 thru 9, at site 11 & 12, at site 22 & 23, and at site 24 & 25. The upcoming full Geo-Tech Report will address their actual potential and include a proposed development plan. The main Code Warning problem area is shown in photographs 16 thru 21, at the Site Map location marked Partial Road "Gap". At this point, no signs of erosion or soil instability can be seen. However, no completion or additional grading will occur at this gap unless/until a County Approved proposal can be secured. CONCLUSION No new grading or vegetation removal will occur until a full Geotechnical Report supporting such additional activity is presented and approved by the County. Only the continued removal of firewood and timber thinning will continue, using existing roads that will be maintained using DNR BMP's to arrest runoff and erosion. Since the disturbed and graded areas have ground cover growing on them and no areas of active erosion or eminent erosion were identified during our inspection, no additional erosion control actions are prescribed at this time. However, Martig Engineering will be monitoring the site thru the 2002-2003 winter wet season. Should any erosion potential appear, Martig Engineering will immediately coordinate corrective measures with Mr. Vermillian. This concludes this Engineering Letter Report. •� of asy .� Sin erely: ►`� � Q K nneth W. Martig,.Jr., FssIoN^L�No` Attachments: #1- Roads & Grading Site Plan, Photo Inspection Record EXPIRES 1-9- o�{ #2- Thirteen Pages (showing thirty-one photographs) 3 42 y . 1/ v �5 Pgr^cc\ No. 32z3 44-00 — aT�_ �.. - _ � gib.....- -. jr i I „t1 'r'^•�c Paj.r csl 34-44- It 1 040 C-)41.f. . DID 10 • £ G.�.�CLI4. Sr sew dh _r� I `#� .'far/�•, :WA jr, M, .r • e ? N; ...�i— � 1L .,ski:.. -'�, f� i .. �+ ;►.�j �. �, r•"_�' �� yo-M Jos �r �.: i;,.. ' ... ,,, - �,<a ,� t 7L�. .0 ._� .; ..L •y tit y� s s f' AF a it f06 ,: WAW r r' 9 ml 11 44"t low , 1 r 4- !R: \k, r ram, •:x ' . r�:� . _ � .,i?'•` '.'4, ■/ �►y a�'r' .. ►v. •: •Cam'. WoO Al "Aij C.. 44 Q �.`a. � � � °.`. - ..vim _��s.,�✓+r...- :..r vie S:. �� �j '9�� ..�.S1.,x�'.�fi{���ler.-•t-ram y'� �"'"�c..� _ 1'h w�. J ' 13 VV -71 4? � 21 ':'4 e �► �. v ' v- Ask Ar Of Af- 7 ✓ ' ��` 1. -_ •! �"��...k ARK' � T: .jq� / S .+s7" �- /y �` •��� �„ • !� ^ ...ifs.�. _ � ,1�'�`4� 4��� \�{ '.'.^. ?'...i. ` �Wt �ti a� lJ+y� Ma e_. • � � '\may \ '` � �a �tFy. x� � V" ,44 `�,���t14 yi''ys 1:�'•,�; ii�.x �,u\ °-+ . `''�E �.. ,4 �� 1l�',. ..R� �� + ��.. j 1'_f� _ 3 /,rl�I.... yam.,, • ,Moo'- AV 'r lw � •a i i XTt` _ Z I � •'•� ,."' fir- �'' ... + r. i ` r �,► :. 4 '�� `�. mot„ �' ,. _ _ � - .._ tom, s.� � '�Y .... - -4� � _ ._-r a 4 .'R r ,r S }i� +w YA .x k w.' ��G - n .� � r r fir- t 1+ F � '._ ` �tT► �r i ��;' r �,.. �, yy, t �y +�:'. ,� �' It 2 �.� �•.�- v` ~,S ��" '�`�' - . -Y�. • r�-� '"L _ ;: �� .!�. ice.- �*`�.��' .� �w: `�� i V a 6 lr. ' r J j•ti � J" .S � r J 1- All �,r!• JPl ' ..44 9Ilk ^ 7��ylot a"` 4'4 4�e«'�-h�'^„ `" .. �:�`•�gtl 5�, �'�,s',;'^T�� �e.� yt°.����, � w �`,�,_a .a .� �i n •.a �.�`-..:;fir•, k, of _ �•�' j, a� DIY �4 h v i ,;sv il kil, MA n •' 1 y Y s li s - A 30 L ���7' r\ � - t �s pis 'i.• :a s n1' +rya ay. t I� i MARTIG ENGINEERING A44ac-�,v",e`4 lt:M P.O. Box 11850 J-L-0,n 7-61 z o 0 Z Olympia, WA 98508-1850 G e,o-1-e-4 R e o v (360) 754-9687 f o V- pa,.C-t l N bt,r July 26, 2002 3Z 54-44- 00000 Mason County Department of Community Development 426 W. Cedar P.O. Box 578 Shelton, WA 98584 Attn: Pam Bennett-Cumming, Land Use Planner Re: GEO-TECHNICAL REPORT for: Property Owner- Jerry Vermillian (10237 Kiwa Dr. SE, Olympia, WA, 98513) Parcel Address- 8371 SR 106 Union, WA 98592 Phone Number- (360) 491-8234 Tax Parcel Number- #32234-44-00000 Proposed Project- Add new Master Bedroom & Garage to existing Residence. Response to Mason County Letters, INCOMPLETE APPLICATION SUBMITTAL OF FULL GEO-TECHNICAL REPORT (supplement to existing application) Dear MS. Bennett-Cumming: Martig Engineering has completed a full Geo-Technical Report for the above referenced Vermillian project, as a supplement to his original application. As a result of our investigations outlined within this Report, we can affirm that all potential Landslide Hazards can be overcome in such a manner as to prevent harm to property and no significant Environmental Impacts will result if this project is permitted as outlined within this Report and its attachments. PROPOSED PROJECT Jerry Vermillain proposes to construct an addition to his existing single-family residence, at the above referenced Parcel, and has previously submitted an application to do so. The addition includes a new Master Bedroom (with bath) on the west side and a new Garage on the east. 1 The Vicinity Map (Attach: #1) shows directions to the Parcel along with a photograph of the existing entrance to the site from Highway 106. The proposed location of the new additions are shown on the Vermillian Site Plan (Attach: #2), on that portion of the total Parcel located north of the Highway. The following discussion summarizes our: Site Investigations; Research of Site Conditions; Analyses; and Conclusions, allowing this Geo-Technical Report to be completed for the above referenced site. GEO-TECHNICAL REPORT 1. Geology, Soils, Groundwater, Landslides: This site is shown on the Mason County Coastal Atlas Maps (Attach. #5 & #6). Attach. #5 shows the residence located within a Stable designation, with the adjacent land to the south being designated Intermediate. No landslides are designated near this site. Attach. #6 shows that the site soils are an Alluvium of sands and gravels which allow moderate infiltration and low runoff. The adjacent soils to the south are Pleistocene gravel deposits older than Vashon Till which stand at steep natural slopes for long times with high infiltration and low runoff. The Mason County Soils Survey identifies the site soils as Everett Gravelly, Sandy, Loam and indicates slopes of 5 to 15% (measured to be in the 5% range at the existing residence). These soils are well draining and consistent with the Geologic Conditions reported in the Atlas. The adjacent soils to the south are shown to be Alderwood Gravelly, Sandy, Loam with slopes 30 to 45% (found to be approximately 50% on the Union Quadrangle Map, see Attach. #4). We found no evidence of slides or slope instability during our site inspection visit nor did we find any using DNR stereo Aerial Photographs dated 1989, 1995, 1997, & 1999. A 1" = 500' scale copy of the 1999 DNR Photo (Attach: #7) shows the stable site. The site upon which the existing residence is situated, and the new additions will be added, is isolated and sheltered by the construction of Highway 106. The Highway ditches capture both surface water runoff and shallow groundwater interflow and convey them to the Canal easterly of the residence. Only the precipitation falling directly this northerly portion of the Parcel introduces water into the site soils. Since the surface rapidly infiltrates precipitation, no surface water flow can exist. Even the roof drains from the existing older residence do not need any formal drainage system, nor will the proposed additions. 2 Given the geologic conditions, we did not expect to find, nor did our site inspection encounter, any horizontal subsurface groundwater interflow thru unconsolidated build in site or on the adjace nt slopes soils that could cause slope instability on the g 1 P within 300 to 400 feet of the existing residence (located along the fall-line thru the residence). NO NEW CLEARING OR MEASURABLE NEW GRADING will occur . The existing cleared site and flat grade, shown on the site plan and in the photos, will allow the additions to be constructed as proposed. 2. Site Plan of Important Geologic Features.- Two Geologic Maps are presented (Attach: #3 & #6). The 1" = 500' scale USGS Quad Topographic Map (Attach: #3) and Section A-A from it (Attach. #4) show the site and its surrounds. This map shows that offsite runoff can be expected to bypass the site to the west and to the east, thru clearly visible Ravines. Section A-A shows that the steeper slopes, upgradient from the existing residence, are a couple of hundred feet away. Therefore, no measurable threat of landslide danger exists. 3. Location of Soil Exploration Holes/Probes: The above described soils formations that exists at and near the site are exposed as cut-slopes along older logging road grades on the north portion of the Parcel. Additionally, previously dug septic system soils test pits remain at various locations along the hillside on the southerly portion of the Parcel, confirming the reported soils. Given these exposed soils, no additional soils test borings or test pits were required to confirm the conditions and type of the site soils. 4. Cross Sections showing slope disturbances: No new excavations or grading will be necessary to construct the new additions as proposed. The driveway to this site exists. In any case, NO DISTURBANCE TO ANY SLOPE/BANK will occur. Section A-A shown on the USGS Quad Topographic Map (see Attach: #4) shows the cross section thru the proposed new additions. 3 5. Slope Stability Discussions: significant As discussed within this report, the proposed activity will not create g environmental impacts and no landslide hazard will be induced when the new additions are constructed. The site is safely set back from all slopes so no activity will disturb them in any way. The site, in its existing condition, supports an older existing residence that is protected on the north by an existing bulkhead and by Highway 106 to the south. The site is already cleared and graded flat to accommodate the new additions without further clearing or grading. An existing driveway leads to the site. 6. Drainage, Septics, Water, Placement: This proposal is for a new additions to an older existing residence that already has water & septic. The roof drains for the new additions do not pose a problem since the site soils infiltrate very rapidly. The roof runoff can either drain directly to the ground with no gutters, or gutter downspouts can be piped directly to an outfall at the existing bulkhead. 7. Clearing & Grading Plan: No new clearing or grading is necessary or proposed. 8. Erosion Control Plan: During construction, since no new grading will be necessary, special erosion control measures will not be needed. Since the driveway and yard areas will remain intact, only rainfall falling directly upon the new garage footprint will be present. This small amount of runoff will readily infiltrate into the flat site soils (no offsite runoff is tributary to the new additions footprint). After construction, any disturbed soil should be planted with grass seed and covered with mulch or simply covered with 3 to 4 inches of loose straw. 9. On-Site & Off-Site Impacts: In summary, no adverse environmental impacts nor landslide triggers will result if this proposed development is permitted as presented within this Geo-Technical Report. 10. Final development Conditions: Existing site conditions will be maintained and no new clearing or grading is necessary. Therefore, no special conditions are necessary for this proposed new garage. 4 I, Kenneth W. Martig, Jr., PE, of Martig Engineering have completed the required Geo- Technical Report as document within this letter Report and its attachments. I am familiar with this site, having lived in the area for decades and having visited and inspected the site and its surrounds. As documented, potential landslide hazards have been overcome and no significant environmental impacts will result if this proposal is permitted as discussed above. Ce ified by: enneth W. Martig, Jr., PE Attachments: #1- Vicinity Map and Site Entrance Photo #2- Vermillian Residence Additions Site Plan #3- USGS Union Quad Topography Map (with Cross Section A-A) #4- Section A-A Drawing #5- Mason County Coastal Zone Atlas Slope, Stability Map #6- Mason County Coastal Zone Atlas Slope, Geology Map #7 - DNR Aerial Photo Map (1999) k� 0 � '� CISTEP ? �SS��NAI.ENG` EXPIRES 1-9- 1 5 o� Q f)CO V l G - v��-� 4 `� 4ri ' Sic Pique, Show the following on the sit kian Lot Dimensions -Flood Zones 4Ff—/"—A'qCN Existing Structures fences Ars/ 65k O Stucture Setbacks /Driveways A-1� Water Lines -Shorelines 6"-K4cAd— Drainage Plans Ay,'st4A Aor /`topography Septic System ,- -Wells Indicate Directional by(N,S,E,W,etc.) Proposed Improvements Easements in relation to plot plan Name of Flanking Street SK-l of of1114 E APPLICA14T TO DRAW PLAN BELOW SEE AV0Y—q(-- jD '5A'we y t AN13 S cgcE— ��� / / Exist�N� cpn►cJ�.�6_'t'G Q uLk Hfi►4D M }STI'�� kv 3 � - Q>?a 5 s21o6��/�w G a �,-� - • ■ • ■ s ■ Q ,r • • S�} Q _ 11 1l --- '' R it = soo S e C- � It - 5-0 / --j1 5 ; 0.Svo 50 lob E�c�st Resla.��e S►,o�1�wz 400 3ry 3p0 2S'D zoo ISo 1 cv 5'o r7 v 5 f1u�W 3uvnOS S 311W 031OA03H OOZ 666-Zv 38vnOS S RIHM 0310A3OH OOI 66--ZZ6 3Wn3s13HS 0" 6CZ B3HVnOSStl3A3S Z8ZO F ue18,;1¢uo/IeNM 3HVO 133HS OS H3 3kdnOSS S 3HS O09 ZOL-Et Mason County Slope Stability YVII Tahu a / e Tah U rs Sisters P — S C 00 • • •ram •••.�'• /��-'!�; L�� {i J%�/ •,� f// �`r ��� �,_;,--� . •;-'/•�� � i :'Ire--� ..% , ,-�,'/'=.. 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