13 46TH ST SW 2016-01-01 MF Import

T DAVID L. NELSON AND ASSOCIATES, INC. �r Consulting Engineering Geology �I Octoher 6, 1992 Proje:ct No. 9892 � Page 3 w The general s;:ratigraphy at this location is observed to consist � of (beginning with the pounaest) , a glacial drift (dense silty � sand with gravel and sandy �i.�t) cap, overlying medium dense to dense advance glacial outwash (slightly silty sand, o�ith gravel � , orerlying an interglacial (stiff sil� and fine sand) deposit. i� The soils observed within the upper elevation areas, anri encountered within the test pits, were determined to be the � glacial drift, known to occur in the area. The soils observed within the upper and mid steep slope appear to be advance outwash sands. The soils indicated near the toe of the slope were the interglacial stiff silts, a].so known to occur in the area. � Local fill was observed within portions o£ the site, and encountered in two of the four test pits. The fill area within � the northweste.rn portion of the site zppears to be composed primarily of organic debris, including logs. This material is at least 3 feet thick, and is not considered suitable for any geotechnical use. Fill mound areas within the portions of the !� site just east of 46th Street SW appear to be derived from off- 'i site, wher.e soil fill has been mounded as waste material. The i�ill areas generally consist of brown, loose, silty sand with � scattered organics, about 1 to 2 feet thick. Hydrologic Conditians � Ground water was not observed within the proposed development portion of the site during our site visit. Wet soil conditions were indicated deeper withir. the sand deposits of TP-4 , perhaps � indicating local trapped or perched water conditions . We did observe an area of outcropping ground water on the slupe, about as shown on the Soil Profile. This outcropping ground water is ,1 considered due to the occurrence of the underlying, relatively impermeable stiff silt deposits, and the overlying permeable sand '� deposits. Where ground water along this interface meets a slope, outcropping ground water conditions normally occur. Seasonal � perched water may occur within the near-surface soils above the denser glacial drift deposits during the wetter periods of the year. � SENSITIVE AREA EVALUATION ( The subject site area was evaluated for sensitive area Ievaluation, as recommended by the City of Everett. We have reviewed the geological aspects of the site with respect to the following sensitive area characteristics; 1) steep sl�pe and � landslide hazard; 2 ) seismic hazard areas; 3) erosion hazard and 4 ) springs and qround water seepage. We discuss these potential elements below. I I �_ .v: __::__ __