4927 23RD AVE W 2016-01-01 MF Import

DAVID L. NELSON AND ASSOCIATES. INC. Consuliing Engineering Geology September 19, 1989 Project No. 12489 ' Page 3 Over��ing the native ground throuuhout the explored portions of the site ar�r I deposits of artificial fill . This `ill was found to vary in thickness and composition across the area. Where the fill was found to be the thinnest, it � generally consists of about 1.0 to 1.5 feet of brown, grey and black, loose, mixed silt, sand, gravel and scattered organics. Where the thickest, the fill � was generally found to consist of about 6 to 7.5 feet of black, brown and ' grey, very loose io loose, mixed organic material (logs, stumps, roots, etc. ) , Iand silty gravelly <�nd. The thickest fill areas appear tn be in the vicinity of TP-3, TP-5 and TN-6, within the general central portion of the upland area. , This may indicate that an old swale occurred within this portion of �he site, I �dhich was filled to achieve the present surface gradient. , HYDROLOGIC CONDITIONS The ground water table was not ercountered within the test pits performed laround the site area. However, wet to very wet conditions were observed � within the weathered zone and fill materials of the thicker central fill area i previously discussed. This may be due to perched water within the area of the � old swale, just• above the dense fine grained native basal deposits. 'Ae would � expect this wet to very wet condition to be chronic during the normally wetter periods of the year. ) SLOPE STABiLITY A general slope stability assessment of the top-of-slope and steep slope � portions of the site was performed. Our obser�ations indicate that debris filling has been performed along the top-of-slope, and just below, causing 1 s�me deterioration of the stability within this area. The debris fill , which consists mostly of cuttings of brush, grass and yard materials, has begun to fail down the slope, and has exposed some of the native soils on the slope to 1 erosion. In addition, in the vicinity of TP-2, the site appears to have been i graded to allow surface water to freely flow over the top-of-slope and onto � the steep slope below. Exposed soil can also be observed within this area. Some undercutting of the top-of-slope was observed, which also exposed the � native soils to erosion and weathering. The larger vegetation on the top-of- �