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Moffatt & Nichol Redwood Shores / San Carlos Airport Levee, San Mateo County PROPOSAL FOR LEVEE CERTIFICATION SERVICES 8585.000.001 June 26, 2009 Page 2 Code of Federal Regulations Section 65.10 (44 CPR 65.10) included as Reference 3. Reference 3 provides a common-language summary of the salient points of 44 CPR 65.10, relevant to the engineering information required for levee certification. As you know, the certification of a levee must be completed by a Registered Engineer who is certifying that the seven criteria under subsection (b) of 44 CFR 65.10 are met by the subject levee. These seven criteria are: 1. Freeboard 2. Closures 3. Embankment protection 4. Embankment and foundation stability 5. Settlement 6. Interior drainage 7. Other criteria (defined by FEMA for unusual situations and high vulnerability) We believe that the approach to the project to this point has been practical and appropriate to the data available; however, we also believe that gathering limited additional data would be prudent in order for a Registered Engineer to take on the responsibility associated with certifying the geotechnical aspects of a flood protection levee. Based on our experience on levee certification projects in New Orleans and California, a higher level of documentation and verification of current soil characteristics is expected by FEMA and their expert reviewers. We. understand that the City of Redwood City intep.ds to self-certify the subject levees with supporting documentation prepared by consulting engineering companies. We further understand that they will likely select to have construction quality control services provided by another firm. Below is an outline of our proposed scope for levee certification. SCOPE OF SERVICES PHASE 1 - Ootional SUDolemental Geotechnical Exnloration Along Redwood Shores Levee As described in our Preliminary Geotechnical Evaluation (Reference 1), we recommend performing additional exploration along the crest of the levee as part of the :final levee certification. We provide an optional scope of work should the City select to perform this confinning exploration. Based on our review, the historic site usage and numerous borings highlight a general homogeneity within the subsurface stratigraphy. It is our opinion that the previous borings include enough stratigraphic information to establish general analysis cross sections. However, it is important to note that only a limited number of the borings were drilled in areas where the levees appear to have been constructed over previous natural drainage channels. Both the shear strength and settlement potential of the types of foundation soil generally anticipated at the project site are dictated by the stress state of the soil. Since we had limited recent strength and consolidation data for the site soil (the majority of these data are several decades old), we used