15 ATTACHMENT 9 - Laserfiche WebLink

ATTACHMENT 7 Sri ~t ~ , ,~,~ r r 4 ~ ~4,7~. ..~ F, . ~~. ` ~ fit ALAN KROPP & ASSOCIATES, INC. G F, d T E C N f: t ~~ A L .: ^ N :3 LI L f A N T S June 12, 2007 1696-16, L 27902 Mr. Steve Otto City of Pleasanton Planning and Community Development P. O. Box 520 Pleasanton CA 94566 ~~~~~ V ~D JUL - 2 2007 CITY OF PLEASANTON PLANNING DEPT, RE: Supplemental GeotechnicaUGeologic Peer Review Sarich Parcel Development Pleasanton, California Dear Mr. Otto: ALAN KRDaP. CE, GF_ JAMES R. LOTT. CE, GE \NAYNE M.4GNUSEN; CE. C-E WILLIAM K. VJIKANDER., CE, GE DONA K. MANN, CE D^NALD L. R6Y, CE T!-ioMAS M. BRENCIC. CE At your request, we have performed supplemental geotechnical/geologic peer review services for the proposed development of the Sarich parcel. This property is located at 1630 Vineyard Avenue in Pleasanton, California. We previously performed a peer review of earlier documents regarding the development of this site and summarized our conclusions in a letter to the City dated January 30, 2004. We recently received two additional letters prepared by the project geotechnical engineer (Terrasearch) dated June 15, 2004 and March 12, 2007. It should be noted the March 2007 letter is identical to the June 20041etter except for two new paragraphs related to the existing stock pond on the property. The purpose of our current pier review is to review the new letters and conclude whether the work presented adequately addresses the issues raised in our January 30, 2004 letter. There were three primary areas of geotechnicaUgeologic concern raised in our previous letter. These were: • East side landslide • Estate lot cutslope • Stock pond seepage Each of these areas is discussed individually below. East side landslide As noted in our original review, Nilsen et al. (1975) shows a large landslide on the southeastern margin of the site (map attached). This landslide is larger than the questionable landslide, idetilified by Majmundar (1991), discussed in the initial Terrasearch report. An uphill portion of this slide is mapped on the site property. Shallow Test Pits (#1 and #2), provided in the supplemental letter from Terrasearch, show stiff clays and dense to very dense gravel and sand. Although detailed information is not provided on the nature of the contacts between the overlying colluvial silt and clay and underlying sand and gravel (likely of the Livermore Gravel), the logs of the test pits do not show landslide features (landslide planes and/or seepage). In addition, measured bedding 2 7~ Ll .-s ..:: T T Li L::< A F_ N i_t c :3 E R K E L E Y, != '~ '3 ~? 7 4 I E L 5 1 0. 8 4 1 . ;~ O 9 S FA :~C. '~ 1 I] .. H --1 1 E 3 5 "7 . i. v .v ..~. K. r2 U F P, t:: O tai