4728 COMMERCIAL AVE 2016-01-01 MF Import

t Robcrt Kincaid Junc 27. 2007 Page 4 Arcas sloping betwcen 25 and 40 perccnt and underlain by glacial advance outwash sand (Qva) also meet the City of Evere[t criteria for erosion hazard areas. This includes the azea between the top of 40%n slopc line and the top oP fill line shown on Fi�ure Z. After rcgrading the stecp face of thc fill soils within thc setback buffer to a 3H:1 V (33 percent) slope, the regraded arca will also mcet thc critcria for an erosion hazard area. The regraded arca will not extend bcyond thc setback buffcr describcd above and shown in Pigurc 2. It is our opinion that no additional setback bufPcr from this erosion hazard arca is necessary,and that the reconunended sctback buffcr,togethcr with uppropriate construction procedures,proper drainage and crosion conVols, and prompt rcvcgctation will adequatcly protect both thc proposcd devclopment and the critical arca. SITE PREPARATION AND EARTHWORK Wc recommend Ihat all sod, organic soil, fill and debris be removed from setdement sensitive areas (c.g., building, pavcment and slab areas). The subgradc surtace in slab and pavemcnt areas should be proof-rolled with heavy rubbcr-tircd equipmcnt after cxcavating to the dcsircd grade. Thc nu�posc of the proof-rolling is to bring the necu�-surfacc soils to a uniform dcnsity and to identify any loose areas which mi�h�rcquirc recompaction or removal and replaccmcnt with st�vchiral fill. Temporary cut slopes �aithin the medium dense or deese native soils may be inclined as stecplyas I I-I:I V and,e�cept forminorsloughing,can Uc expected ro stand at that inclination for a period of sevcral wceks il'protccted from drying and erosion. Thc lower portion of cut slopes in densc native soils may bc cut vcrtic:�lly up to a maximum oP 4 feet in height if approved by us bascd on observations during excavation. Temporaq�cut slopcs in existing loosc or fill soils may bc inclined as steeply as I.SH:1 V if protectcd from drying and crosion; this may be incrcased to I F L•t V for medium dense or dense�II soils iC approved by us based on observations during eecavation. Protection from drying applies to natural soil moisture only; watcr should not be added to tcmporary cut slopes ro impro��e stability. Pcnn:mcnt fill slopes should be inclincd no stecper than 31-L•t V. STRUCTURAL FILL t\II new fill in setUement-sensiti��r :ueas should be placed :�s compacted structural fill uftcr thc sitc has been prcpamd as describcd abovc. All structural fill material should be Gec of dcbris, organic contaminants and rock fra;mcnts largcr than 6 inchcs. The suitability o[ material for use as strucwral fill will depend on the gradation nnd moisture content of the ` soiL As thc .unount of fines (material passin; No. 200 sicve) increases, soil becomes 7505 West Lake Sammamish Parkway NoA�ieast Redmond,Washington 98052 425•882-4850 wWw.tubbs.Com � I�