SU0011633 SSNL - Laserfiche WebLink

Home Browse Search

KL E/NFEL DER brpht l't pp:c A•9hSptu:rpni. 6 FIELD INVESTIGATION In order to evaluate the subsurface conditions at the project site, on March 13, 2017, one soil profile boring (P-1) was drilled within the proposed leach field area to a depth of about 25 feet below existing site grade. The boring was drilled using a CME 75 truck-mounted drill rig equipped with 6-inch O.D. solid-stem auger. The approximate boring location is presented on Figure 3. A representative with our firm maintained a log of the boring and visually classified the soils encountered according to the Unified Soil Classification System. A Graphics Key is presented on Figure 6 and a Soil Description Key is presented on Figure 7. The Boring Logs are presented on Figures 8 through 10. Following completion of the soil profile boring, percolation test holes P-2 and P-3 were drilled within the proposed leach field area to depths of about 3 and 25 feet below site grade. The approximate percolation test hole locations are presented on Figure 3. Following drilling, the sides of the test holes were scored, and significant loose material was removed from the bottom • of the holes. The percolation test holes were then prepared by first placing about 2 inches of fine gravel at the bottom of the holes and installing a 4-inch diameter, perforated PVC pipe. Before 8:00 AM on March 28, 2017, about 12 inches of water was placed in the holes for pre-soaking. On March 29, 2017, the percolation tests were started at about 8:25 AM in accordance with SJCEHD accepted guidelines, using clear potable water. The holes did not exhibit sloughing or caving and contained water prior to testing. From a fixed reference point (a marked location on the side of PVC pipe), the drop in water level was measured in approximate 30-minute intervals for 4 hours (SJCEHD Procedure #2), refilling as necessary to maintain the prescribed amount of water over the gravel. Under the observation of a representative from the SJCEHD, the last 30- minute readings of the tests were observed and the percolation rates, in minutes per inch, were calculated. Copies of our field percolation test results are attached on Figure 11. Groundwater samples were not obtained for nitrate (NO3) testing because there is no domestic well located within the parcel. We understand the proposed structure will use water provided by the city of Stockton. The boring and percolation test holes were located in the field by visual sighting and/or pacing from existing site features; therefore, the locations shown on Figure 3 should be considered approximate. 20173772.001A/ST017R57809 Page 6 of 15 April17, 2017 ©2017 Kleinfelder www.kleinfelder.com