ARCHIVED REPORTS_[REV] MAY & JULY 2014 RCSI

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3 -13 of Water Resources, 1981). This precipitation station was selected due to its long and reliable period of record and its proximity to the project site. The precipitation depth-duration-frequency data t:lSe€I-for the project site was obtained from the Stockton Weather Station Number 800-8560 (except where noted ): development and des ign a re: • 100-year, 24-hour storm intensity of 3.58 ~ inches,: • 1,000-year, 24-hour storm intensity of 4.924:41 inches,: • 100-year annual precipitation of 25.42 inches • Annual mean precipitation of 14.27 inches *Source: No n-Water Corre ct ive Ac t ion Pl a n for Forw a rd landfill . Ge olog ic Associa tes . Nove mber 2011. The Gur rent "'.lOR Orde r No. 94 014 lists the 24 hour max i mum precip itation for the 100 ye a r event an d the 1,000 year event as 3.2 5 and 4.11 inGhes, respective ly. From the late 1980s to the early 1990s as well as recently , California ~experienc l.ngea a severe drought. Although the precipitation data available during this period may not represent the statistical min i mum precipitation that could occur at the project site, the likely minimum precipitation range antiCipated during the service life and post-closure period of the landfill can be estimated. Table 10 presents monthly average total precipitation tetaJ.s recorded for the Stockton Area at the Western Regional Climate Center, Stoel{ton Weather Station OffiGe (,AlSO), approximately 7.6 miles northwest of the project site , for a period of 62W years, between 195048 and 20 12Q.7.. During this period, the minimumaverage annual precipitation recorded for the Stockton areaa t the airport was approximately 17.8713 .96 inches. Considering the drought conditions experienced during that period, a minimum annual average precipitation of 17.87~ inches during the service life and post-closure period of the landfill site was estimated. As shown in Figure .8.9 , the Forward site is located between the North Fork and the South Fork of the South Little john's Creek . 8ased on the Federal Emergency Management Agenc y (FEMA ) Flood Insurance Rate Maps (FIRMs) for the San Joaquin Valley . Forward Landfill is located within four FIRM Panels: 0490F: 0495F: 0630F; and . 0635F. From the FIRM Legend. the ma jority of the landfill (including the RRF and Composting Facility ) is located within "Zone X". which are areas determined to be outside the 0.2 percent annual chance of being in a floodplain. The area east of Austin Road at the North Fork of South Little john's Creek is labeled as "Zone AO, (Depth 1 )". which are areas with flood depths of one to three feet. This information was factored into the North Fork realignment of the South Littlejohn's Creek relocation design.is not located within the 100 yea r flood plain. The entire landfill site is '1t'ithin Flood Zone Designation C, which encompasses areas of min i mal flood ing during the 1 00 ye a r, 2 4 hour storm event (Federal Insurance Rate Map, U.S. Dept. of Housing and Urban Development, May 15, 1980). Areas designated as "Zone Cn are areas of m i nima l flooding that lie outside the 100 year f lood plain. SinGe the landfill s ite is not located within the 1 00 year flood plain, an engineering analysis to de t ermine hydrodynamiG forces that would result from SUG h an event is not necessary, as specif ied by Section 2595(d)(2) of Chapter 16, Tit le 23. The North Fork of South Littlejohn's Creek was relocated to allow continued deve lopment of the Forward Landfill. The 7.600-foot reach of the creek relocation was designed to channel Forward Composting Facility SWT Engineering Report of Composting Site Information -May 2014 z:\projects \allied waste \forward\resource recovery facil ity \5 yr perm it rvw 2013-14\rcs i 2014\text\se c 3 -revtr .doc