2018.02.05 CC Packet - Laserfiche WebLink

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A W+r7B NOTICE TO REPORT USERS BORING LOG INFORMATION & Rssociaees, Inc. Subsurface Profiles The subsurface stratification lines on the graphic representation of the test borings show an approximate boundary between soil types or rock. The transition between materials is approximate and is usually far more gradual than shown. Estimating excavation depths, soil volumes and other computations relying on the subsurface strata may not be possible to any degree of accuracy. Water Level WSB & Associates, Inc. took groundwater level readings in the exploratory borings, reviewed the data obtained, and discussed its interpretation of the data in the text of this report. The groundwater level may fluctuate due to seasonal variations caused by precipitation, snowmelt, rainfalls, construction or remediation activities, and/or other factors not evident at the time of measurement. The actual determination of the subsurface water level is an interpretative process. Subsurface water level may not be accurately depicted by the levels indicated on the boring logs. Normally, a subsurface exploration obtains general information regarding subsurface features for design purposes. An accurate determination of subsurface water levels is not possible with a typical scope of work. The use of the subsurface water level information provided for estimating purposes or other site review can present a moderate to high risk of error. The following information is obtained in the field and noted under "Water Level Measurements" at the bottom of the log. Sampled Depth: The lowest depth of soil sampling at the time a water level measurement is taken. Casing Depth: The depth to the bottom of the casing or hollow -stem auger at the time of water level measurement. Cave -In Depth: The depth at which the measuring tape stops in the bore hole. Water Level: The point in the bore hole at which free-standing water is encountered by a measuring tape dropped from the surface inside the casing. Drilling Fluid Level: Similar to the water level, except the liquid in the bore hole is a drilling fluid. Obstruction Depths Obstructions and/or obstruction depths may be noted on the boring logs. Obstruction indicates the sampling equipment encountered resistance to penetration. It must be realized that continuation of drilling, the use of other drilling equipment or further exploration may provide information other than that depicted on the logs. The correlation of obstruction depths on the log with construction features such as rock excavation, foundation depths, or buried debris cannot normally be determined with any degree of accuracy. For example, penetration of weathered rock by soil sampling equipment may not correlate with removal by certain types of construction equipment. Using this information for estimating purposes often results in a high degree of misinterpretation. Accurately identifying the obstruction or estimating depths where hard rock is present over the site requires a scope of service beyond the normal geotechnical exploration program. The risk of using the information noted on the boring logs for estimating purposes must be understood.