NS-3092 - Zone Change for 1801 East Chestut Ave

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SANTA ANA REZONE PROJECT INITIAL. STUDYIMITIGATED NEGATIVE DECLARATION depth ranging between zero to approximately 460 feet below the surface.39 Although younger alluvium deposits (Qya) have a low to moderate potential for containing significant paleontological resources due to their young age, the rock units are known to yield paleontological resources such as the remains of Pleistocene-age mammals deposited by streams from higher elevated areas, as well as marine vertebrates and several classes of marine invertebrates.As such, a paleontological records search was conducted by the Los Angeles County Museum of Natural History on February 16, 2025, to determine whether any fossil localities have been uncovered in the project region and related rock units to indicate whether ground-disturbing activities during the construction phases of the proposed project could yield significant paleontological resources. While the records search did not locate any significant fossil localities uncovered in the direct project area, five localities were identified in the same sedimentary deposits that may constitute the stratigraphy beneath the project site consisting of both marine and nonmarine vertebrates and marine invertebrates. In addition, an excavation project approximately 3.4 miles south of the project site yielded marine invertebrates and bone fragments of marine vertebrates within a sandy lens about three feet below the surface near Peters Canyon Wash.40 The proposed project largely consists of repaving an existing parking lot; however, excavation would occur around the footings of the proposed solar structure. Since the younger alluvium deposits (Qya) have contained significant paleontological resources, ground-disturbing activities may uncover and potentially damage a unique paleontological resource. The proposed project would be subject to compliance with SC 2.5-1,which provides measures to implement if paleontological resources are encountered during construction activities such as temporarily halting construction and contacting a qualified Paleontologist to analyze the significance of the discovery and to develop a paleontological resources impact mitigation plan, if necessary, prior to resuming ground-disturbing activities. Since construction of the proposed project would be required to abide by SC 2.5-1, the proposed project would not destroy a unique paleontological resource and impacts would be less than significant. Standard Conditions SC 2.5-1 In the event that paleontological resources are encountered during grading and construction operations, all construction activities shall be temporarily halted or redirected to permit a qualified Paleontologist to assess the find for significance and, if necessary, develop a paleontological resources impact mitigation plan for the review and approval by the City prior to resuming excavation activities. 39 Schoellhamer,J.E,J.G.Vedder, R.F.Yerkes,and D.M.Kinney. 1981.Geology of the Northern Santa Ana Mountains, California. 40 Beth Padon.2022.Final letter report for Archaeological and Paleontological Monitoring at Warner Avenue Storage Facility Phase 2 at 2960 Warner Ave,Irvine.August 19. 56 FCS Ordinance No. N.4T _tlnns.shaeepainl.t6m/Sites/PubllcaflonsSllefShdtEd Docaments/Publicati—ILllent LPN-JNIJ6327f0327#4M7/ISMND/0327d047 Santa Ana Rezone Proteet ISMNDAM Page 68 of 118