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Home My WebLink AboutGeoTech Engineering Report - BLD Engineering / Geo-tech Reports - 1/16/2000 Y.sr ��► -f RECEIVED FEB 1 5 2000 24 0 6 7,6 S MASON CO. DCD - Geotechnical Engineering Report Henningsen Property — 39 acres Parcel No. 12329 23 00000 Belfair, Mason County, Washington ton .Prepared for: Skillman Brothers, Inc. 5541 Steamboat Island Road NW Olympia, WA 98502 (360) 866-8589 Prepared by: Morta Engineering and Testing P.O. Box 250 Ocean Shores, WA 98569-0250 (800) 590-0958 January 16, 2000 I January 8,2000 Report No. 001 Page 1 of 3 Morta Engineering & Testing 240676831 To: Skillman Bros.Inc. 5541 Steamboat Island Rd.NW Olympia, WA 98502 (360) 866-8589, (360)791-0082 Attn: Bob Skillman Subject: Geotechnical Engineering Report on the 39 Acre Henningsen Property Parcel No. 12329 23 00000,Belfair,Mason County,Washington References: Washington Forest Practices Act RCW 76.09,dated June 1993 Prepared by DNR Forest Practices Division Stormwater Management Manual for the Puget Sound Basin, February 1992,prepared by the Department of Ecology Introduction On December 27, 1999, this geotechnical engineer met with Bob Skillman onsite who is the logging contractor to investigate the 39 acre forested property and prepare a detailed geotechnical engineering report for Mason County. Digital color photographs were taken of the logging site and have been included with this report. This report documents the results of the site investigation which concludes that the slopes are for the most part less than 30 to 35%and that the likelihood of slope instabilities during logging operations are minimal. Conclusions and recommendations have been included at the end of this report along with mitigation measures that have been agreed to with the logging contractor. General Description of the Proposed Logging Area The site is located approximately 4 miles west-northwest of the town of Belfair, WA just off of Sand Hill Road as shown on the vicinity map in Figure 1. The 39 acres is mostly 50 to 70 year old Douglas Firs as shown in photographs 1 through 4 and 28 through 45. There were no signs of streams or seasonal creeks in the area. Slopes on the property were in general less than 30%and in most cases were around 20%or less. Approximately 7 acres located near the southwest corner of the square shaped property has been reserved as shown in Figure 2 and will not be clear cut. Abandoned mobile homes and sheds indicate that this area had at one time been occupied. Different types of trees have been replanted in this area in the last 10 to 15 years. The intent of the owner of the property-is to let these trees continue to grow and acts like a greenbelt area if the rest of the area should get developed. Soil Description P.O.Boa 250,Ocean Shores,WA 98569 (360)289-0958 Bus,(800)590-0958 Toll Free, (360)590-1379 Mobile, (360)538-1736 Aberdeen Laboratory v January 8,2000 Report No. 001 Page 2 of 3 Morta Engineering & Testing Onsite soils investigations indicate that this soil is a relatively free draining reddish brown sandy loam with some 1-1/2" minus gravels as shown in photograph No. 4. There were no indications of clays in the native soils. At the time of the site visit the soils were relatively dry indicating fairly high percolation rates with no standing water anywhere on the property. Slope Stability The maximum slopes on the 39 acre parcel were located toward the northwest quadrant of the property as shown in Figure 2 and were no greater than 40%. This means that in a horizontal distance of 100 feet the elevation of the terrain did not drop more than 40 feet in this distance. There were no signs of sloughing or slides. The Douglas Firs on the property especially in the NW sector were growing straight and vertical with no signs of leaning or of any trunk curvature which would have indicated downward slope movement. The relatively dry soils increases slope stability due to the increased surface friction between soil particles. Near the center of the property and on the east side of the old logging road that bisects the property there were some 30 to 35% slopes. There were no indications of slides in this area either. Since this was a relatively open area very little logging would be occurring here. Mitigation Measures During the logging operations the contractor will construct access logging roads such as to minimize the effect of soil erosion and reduce to a minimum the impact to the existing vegetation. Whenever possible the contractor will restore the access roads back to their natural state for quicker recovery of the logged off areas. Clean up of the site will take place by piling up slash accumulations for later disposal. As mentioned earlier approximately 7 acres will be preserved from logging near the southeast quadrant as shown in Figure 2. The logging contractor has already flagged this area off with yellow survey ribbon. In areas greater than 30 to 40 percent slope no logging equipment will be traveling on these slopes and cutting of the trees will be done manually instead of machines. These high slope areas have been identified in Figure 2. The contractor will be leaving some trees in clear cut area that have full grown green bows all the way around the tree which have little marketable value. Also, care will be taken to preserve the forest floor consisting of salal, fems, and ivy that protect the soils from soil erosion. To compensate for the trees logged off the property, the owner plans to replant the property with new tree saplings approximately 1 to 2 years old. This will also help to preserve the native soils in the future. This geotechnical engineer has recommended to the contractor that a greenbelt be preserved between the existing house located on the south side of the property. The contractor P.O.Bog 250,Ocean Shores,WA 98569 (360)289-0958 Bus,(800)590-0958 Toll Free, (360)590-1379 Mobile, (360)538-1736 Aberdeen Laboratory January 8,2000 Report No. 001 Page 3 of 3 Morta Engineering & Testing has agreed to a 50 foot no cut buffer along the fence line as shown in photograph No. 45. This will reduce the impact of the clear cut operations on the neighbors. Conclusions and Recommendations 1. Approximately '/e of the 39 acres has slopes greater than 30 to 35% with no signs of slope instabilities such old slides, erosional channels, or curved tree trunks which would have indicated slope movement over a period of decades. 2. The soils onsite consists of a reddish brown sandy loam which stays relatively dry even under heavy rainfall conditions and, therefore, increases slope stability due to the higher particle-to- particle surface friction. There were no signs of standing water or seasonal streams in the area. 3. The logging contractor has agreed to a set of mitigation measures that will reduce the impact of clear cutting operations that has been listed in the last section of this report. 4. This professional engineer will be called onto the jobsite by the contractor just prior to logging operations to ensure that the clear cutting operations will proceed per this soils engineer's recommendations in this report. Also, if there is any questions at this time this engineer will be able to answer them. Finally, this engineer will be called out to the jobsite just prior to completion of the job and prepare a final report. If you have any questions regarding this geotechnical engineering report do not hesitate to call me at(800)590-0958 or on my cellular phone at(360) 580-1379. Sincerely Morta Engineering and Testing, Steven P. Morta,P.E., Owner J 'AO �t07 I0NSI�EXvG DCPIRi7 /14/ Z' b G 1 P.O.Bog 250,Ocean Shores,WA 98569 (360)289-0958 Bus,(800)590-0958 Toll Free, (360)580-1379 Mobile, (360)538-1736 Aberdeen Laboratory v 11, U � t • ? FOR MORE DETAIL SEE ENL #5 it , Sta 9 IB 8 �0 RD DEW A c� r, NDEFOSA— �4 zw NE oz y CL w a 5P HSH HATCHERY U 13 18 t 17^` �� D' NE 16 f N LOG P tch °° ' ti0 i zN 90 D,NE j 6Ww 9 • Oq�h H ) Q� a CC �? /f MAK, A I = t RHILL an,0 H-fT Park' = RD �Q� P , NE \ nd Hill 3� TIMBE WKIRK D, Ma 23 24\ - ementary 20 w O j p CKNI(3H z ' I a rrI NIL _ %D. E MRD cs MEEK ILL . Sp < I 3 Is rso 25 LaLaken ation e� 2 26 i W z ist #1 u; fi n'6au tyAnnex ST, N YERLY. J �� R, NE! y "O Bel air Y r , I 51. ir 331YA Misso UIRE L 'NE Cree ci i railhad v, o ynh= l ti of ry ALDER Cal F. LN,NE � `• y� Cove I is Sta lair r•v "�r FOR MORE DETAIL SEE. ENL # I StJ V Sun Beach YL Y x 106 unset/ . 4 D ,ereaur Lake `J J a: y h - BOB SKILLMAN , Y` y 2 ` SKILLMAN BROTHERS,.INC. 5541 STEAMBOAT ISLAND RD. N.W. OLYMPIA, WA 98502 — /'/dJtA BOB, SR. (206) 866-7083 BOB, JR. (206) 86 1 S�L �i�✓LJSlY p/50+�/G�'' O� ,e� �J gL yr,w2 I LLAv� Jam!"• /Lt�ccr AiGoiJv�: A tr �.teen 4eO � i�Ln N7 Ed. p 't Lbcly ,QEJ�Y,,,,s•- b k 13 m It-C As..G 4 ..rt to 10 tjW ot tile JO r ?Ash~ J( x cv/ QvJ45'f rt /"�s�"t r�* "�Ycc,�.r`'S�• cffK t!J IL IL n ; - y t 1 BOB SKILLMAN t" SKILLMAN BROTHERS, INC 5541 STEAMBOAT ISLAND RD. N.W. r OLYMPIA, WA 98502 BOB, SR. (206) 866-7083 BOB, JR. (206) 86 85 Q�Aa�c. dA n� .y 1 ( 2JD L<,a4'r /sin— Mg:;.c.cr �LnNT �j. I /� h vlt�/s••G 0ft-!44 Y LOf/— -iolf J`—�• IY 1 4 ' fJ4 i Q •� '' r �[ 'ti ~ X lI K 2 S Fie 14 Ike rl ID 5 ' t Y - FX /, �srr ��EYc c a�•r `SEv"�' �hF K u! z Z s � �,Q�Y c.✓s9 ftn- . o ! er r 14, � a z - t 2406 O Or- `.1 —N47 27-667' 7 1 t t i 1fJ47--27-5' i F —N47'27.333 or {j r 48 _ r Pit .mot� ,l�,•� -:.. - - .L.• .tip. r c - :t+ �N47�27=1 fi•, ry��j�', N47-'27' l M T IN iziv 3-D TopoQuads Copyright V 1999 DcLorme Yarmouth,ME 040% Source Data:USGS 250 ft Scale:1 :6,400 Detail: 15-0 Datum:NAD2- Fly ,��E V,q TlON Ail O F!L ,E Geotech Engineering Report ,a itle:Photo No. 19 Title:Photo No.20 Title:Photo No.21 gate: Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29, 1999 Description:View from abandoned trailers Description:20%slope in the no-cut zone Description:New growth area in the no-cut the preservation boundary zone -i kk- l� t itle:Photo No.22 Title:Photo No.23 Title:Photo No.24 gate:Dec.29. 1999 Date:Dec.29,1999 Date:Dec.29,1999 escriptiow Another view of new growth Description:20 to 25%slopes in the no-cut Description:These trees will be preserved -nber in the no-cut zone zone in the no-cut zone r I p - %h' ' itle:Photo No.25 Title:Photo No.26 Title:Photo No.27 late: Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29,1999 escriptiom 25 to 30%slopes in the no-cut Description:Abandoned trailer-see Description:Old railroad grade running reservation area attached schematic map for location through the property from south to north Morta Engineering and Testing Page 3 Geotech Engineering Report r itle:Photo No.28 Title:Photo No.29 Title:Photo No.30 late:Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29, 1999 lescription:View of harvestable timber Description:Ground cover consists mostly Description:Abandoned concrete truck left long the old railroad grade of salal,ferns,and moss in the timber harvest area 16. R i � I itle:Photo No.31 Title:Photo No.32 Title:Photo No.33 late: Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29, 1999 lescription:No signs of soil erosion or Description:Mostly 10 to 15%slopes Description:25 to 30%slopes in cleared tides in the timber harvest area throughout most of the 39 acres areas-no problem itle:Photo No.34 Title:Photo No.35 Title:Photo No.36 late:Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29, 1999 lescription: Boundary flags at the north end Description:20 to 25%slopes near the Description:25 to 30%slope areas will be f the timber harvest boundary N-NW boundary area cut by hand Morta Engineering and Testing Page 4 Geotech g Eng ineerin Report r 41h t• a Title:Photo No.37 Title:Photo No.38 Title:Photo No.39 Date:Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29,1999 Description:25 to 30%slopes-signs of Description:Ground cover consists of salal, Description:20 to 25%slopes-signs of slides or potential slides ferns,and moss-will be preserved slides-okay to harvest Title:Photo No.40 Title.Photo No.41 Title:Photo No.42 Date: Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29, 1999 Description:20 to 25%slopes-signs of Description:Timber harvest area consists Description:25 to 30%slopes near NW slide activity mostly of gentle 10 to 20%slopes corner of property-no signs of slides ?V Ile Title:Photo No.43 Title:Photo No 44 Title:Photo No.45 Date:Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29, 1999 Description: Dense groundcover will be Description:Gentlye10 to 15%slopes exist Description:50'foot no-cut buffer zone will mostly preserved for ground protection over most of the area be added along south residential boundary Morta Engineering and Testing Page 5 Geotech g En ineerin Report g t itle:Photo No.1 Title:Photo No.2 Title:Photo No.3 gate: Dec.29,1999 Date:Dec.29, 1999 Date:Dec.29,1999 Description:View of the 39 acre plat from Description:View from SW corner looking Description:View looking NW from the SW ie SW corner north corner of plat near cemetary F- � p itle:Photo No.4 Title:Photo No.5 Title:Photo No.6 late:Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29, 1999 lescription:Soils consist of a light brown Description:View from Sand Hill Road Description:View from Sand Hill Road on andy loam looking at SE toward Henningsen property the west side of property oil3y = a 'itle:Photo No.7 Title:Photo No.8 Title:Photo No.9 late: Dec.29,1999 Date:Dec.29, 1999 Date:Dec.29, 1999 lescription:View of adjacent standing Description:8 foot deep cut along Description:Soils consist of light brown silty mber on west side of property embankment of Sand Hill Road loam with some 1-112"minus gravels Morta Engineering and Testing Page 1 Geotech neer Eng iin Report g I title:Photo No. 10 Title:Photo No. 11 Title:Photo No. 12 Date:Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29, 1999 Description:Another view of the light brown Description:View from Sand Hill Road Description:7 acres of timber will be sandy loam with gravel along the 8'deep looking at adjacent timber on west side of preserved which has mostly new growth hr' , . Of, J J+f! - -1 _ Title:Photo No.13 Title:Photo No. 14 Title:Photo No.15 Date:Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29, 1999 Description:Vacated trailer on the 7 acre Description: 15 to 20 year old new growth in Description:Noble Firs and other trees have preservation area the preservation zone been replanted ,a• i - n rtle:Photo No.18 Title:Photo No. 16 Title:Photo No.17 Date:Dec.29, 1999 Date:Dec.29, 1999 Date:Dec.29, 1999 Description:Other vacated mobile homes Description:This Douglas Fir will be left Description_4'depression area was the site observed in the no-cut zone which is in the preservation area of 5 bedroom drainfield Morta Engineering and Testing Page 2