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HomeMy WebLinkAbout702142013 Geotech Assessmentr r ~ NTI ENGINEERING ~ SURVEYING I 717 SOUTH PEABODY STREET, PORT ANGELES, WA 98362 Engineers D Land Surveyors O Geologists Construction Inspection ^ Materials Testing NT/ (360) 452-8491 1-800-654-5545 FAX 452-8498 E-Mail: infolaDnti4u.com www.nti4u.com July 11, 2007 Mariah Meriam 11530 Seabeck Highway Seabeck, bNA 98380 Subject: Geotechnical Assessment of Tax Parcel #702142013, Located in Section 14, Township 27 North, Range 2 West, W.M., Jefferson County, Washington Dear Ms. Meriam: At your request, NTI Engineering & Surveying completed a geotechnical assessment of the above referenced property consisting. of research of available literature and geologic maps of the area, and a site visit for visual observations. This assessment was in response to a portion of the property being. listed as a "Slight Landslide Hazard" area by the Jefferson County Department of Community Development. The USDA Soil Survey maps the soils in the area of the property as Cassolary sandy loam. This soil is described as sand, silty sand, clayey sand, clay and silt that formed in reworked glacial and marine sediments. The Washington State Department of Ecology's (DOE) "Geology and Ground-Water Resources of Eastern Jefferson County, Washington" 1981, maps the soils in the area of the subject property as Recessional outwash and ice-contact stratified drift (Qvr) and Volcanics, undifferentiated (Tv). The volcanics are approximately mapped on the steeper western side of the property and consist primarily of basalt flow rock. The recessional soil consists predominantly of gravel with some sand, silt, and clay. Visual observations of the surface soils at the property most closely match the recessional soil description. The DOE publication also produced across-section of the subsurface just south of the subject property showing the recessional soil overlying the volcanic rock. Our experience in the area also indicates that the hills and mountains are predominantly composed of volcanic rock with a relatively shallow covering of soil. The property was reportedly logged in 2004 and is now well vegetated with brush in the logged areas, with patches of timber in the areas that were not logged. The eastern and southern portions of the property slope down towards the east as approximately 10°. The northwestern portion of the property is steeper with slopes ranging from approximately 15° down low to ~26° near the top. No springs or seeps were observed on the hillside. There was no evidence of past slide activity observed on the hillside, however some of the trees on the steeper slopes have curved trunks indicating that minor down slope creep of the surface soils is occurring. J11L ~ 9 208 JEffERSO!~ CQ~N?~ E' It is our understanding that you plan to build a daylight basement home at the base of the hillside with an ADU northeast of the main dwelling, and that the development will be approximately 100' away from where the steeper slopes begin about halfway up the hill. Based upon our assessment of the property and our understanding of the project, it appears that the hillside does not pose a landslide risk to the development, as long as vegetation on the hillside is maintained and drainage from the development is properly addressed. If you have any questions regarding this matter or need further assistance, please feel free to contact us. Sincerely, NTI ENGINEERING & SURVEYING Robert A. Leach, P.E., MBA Principal Engineer ~~`- ~~~ Bill Payton, L.E.G. Engineering Geologist G:\Genl6ill\ReportsUUlERM0701.14(27-2).Geotech review.Quilcene.doc ~` ~~~~~~~~1 s ; ~ ,, S. ` ... ~ 4` ._.. , ?-t 2.- O7 ? -~2--a7 r- s ~ . .y iF EXPIRES 12/3W200e NTi ENGINEERING Sz SURVEYING 7i7 SOUTH PEABODY STREET. PORT ANGELES, INI146.962 Engirreers O Land Stgveyas O Geolb~sts Construcitiun /nspectian ~ Materials Testing (360)452-8491 i-800-654-5545 FAX452-8498 E-Mail: ~foOinti4u.can Apri129, 2008 Maciah Meriam - 11530 Seabeds Highway __._ .__.___~e~eGIs~1NA 98380_ _. _- _-. __ - ~.._~_-.._ .._ .._ ____ __._ Subject: Home Site Inspection for Tax Parcel #702142013, Located in SecCion 14, Township 27 North, Range 2 West, W.M., Jefferson County, Washington Dear Ms. Meiiam: NTI Engineering & Surveying completed a geotechnical assessment of the above referenced property dated July 11, 2007.On April 23, 2008, a site visit was made to the property in order to confirm that the marked home site location is consistent with the recommendafion of the geotechnical assessment. The marked home site location is consistent with the recommendation of the geotechnical assessment. If you have any questions regarding this matter or need - further assistance, please feel free to contact us. - Sincerely, NTI ENGINEERING 8< SURVEYING -1-~G Bill Payton, L.E.G. Engineering Geologist 8:1ReportslMERM0701.14(27 2}.home site inspection.Quilcene.doc ~~~~.~~~ J~~~~E~S~~ CO~N~f DCO