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HomeMy WebLinkAbout1998-05-11 City Council (8)City of Palo Alto City Manager’s Report TO:HONORABLE CITY COUNCIL 9 FROM:CITY MANAGER DEPARTMENT: PUBLIC WORKS DATE:MAY 11, 1998 CMR:220:98 SUBJECT:RECOMMENDATION TO SUBMIT AN APPEAL OF PROPOSED FLOOD ELEVATION DETERMINATION IN THE FEDERAL EMERGENCY MANAGEMENT AGENCY’S REVISED FLOOD INSURANCE RATE MAP FOR SAN FRANCISQUITO CREEK RECOMMENDATION Staff recommends that Council directthe Public Works Department to submit an appeal of the revised San Francisquito Creek Flood Insurance Rate Map in order to refine the boundaries of the new maps. BACKGROUND On September 29, 1997, staff reported to Council that the Federal Emergency Management Agency (FEMA) had completed its study of San Francisquito Creek and had submitted a preliminary copy of the revised Flood Insurance Rate Map (FIRM) to the City (CMR:402:97). On December 8, 1997, Council directed staffto prepare an appeal of the revised San Francisquito Creek FIRM and to hold a community meeting to present the revised map to the public for review and comment (CMR:487:97). Staff contracted with Nolte and Associates on December 23, 1997 to conduct an independent review of the revised FIRM in order to determine whether an appeal of the map was warranted. On February 27, ¯1998, FEMA initiated the formal 90-day appeal period, during which time the City or members of the public have the right to appeal the revised map based upon a dispute of a quantitative, technical nature. On March 26, 1998, staff conducted a community meeting to present the revised FIRM to the public, discuss flood insurance costs and special building requirements for properties in the Special Flood Hazard Area, and to seek public input on whether to appeal FEMA’s revised FIRM for San Francisquito Creek. FEMA’s 90-day map appeal period will end on May 28, 1998. DISCUSSION March 26, 1998 Community Meeting On March 26, 1998, staff conducted a community meeting at the Children’s Theatre to present the revised FIRM to the public. Representatives from FEMA and Nolte and Associates assisted staff in making the presentation and answering detailed questions. CMR:220:98 Page 1 of 5 Topics of discussion included the proposed flood zone boundary changes, flood insurance costs and requirements, special building requirements in the Special Flood Hazard Area, and the map revision process and timing. Approximately 200 people attended the meeting, and it was videotaped and rebroadcast on Cable Channel 16 on the evenings of April 15 and 16. Staff’s 45-minute formal presentation was followed by a two-hour question and answer session. Audience questions and comments generally fell into one of four categories: Requests for a description of the cause and extent of the February 2-3, 1998 flooding. Questions on the City’s proposed actions to prevent future San Francisquito Creek flooding. Requests for clarification of detailed aspects of the flood insurance and special building requirements for properties in the Special Flood Hazard Area. Comments and questions on whether or not the City should appeal FEMA’s preliminary revised Flood Insurance Rate Map (FIRM). Several speakers compared the proposed FIRM with the actual extent of flooding on February 2-3, 1998 and commented on whether or not their particular property should or should not be included on the final FIRM based upon their recent experience during the flood. In response, staff explained that although the February flood can be used as a tool in evaluating the general accuracy of the map, one should not expect an exact correlation between the FIRM and the February flood, because the stream flow measured in San Francisquito Creek on February 2-3 was less than the one percent flood event~, and because the levees along the creek did not fail in accordance with the assumptions used in FEMA’s floodplain analysis. Despite some differences of opinion, the general consensus of the audience was that the FIRM should be as accurate as possible and that, therefore, the City should appeal the FEMA map ifNolte’s analysis produces significant mapping differences based upon better ground elevation information. Staff announced that Council would make a final decision on the map appeal at its May 11, 1998 meeting. Independent Floodplain Analysis Nolte and Associates has completed its independent analysis of the area subject to flooding from San Francisquito Creek during the one percent flood event. Nolte used updated ground elevation information from the City’s Geographic Information System (GIS) that is more extensive and more precise than the information used by FEMA’s original mapping consultant. Nolte also made minor modifications to its mapping based on a field 1The one percent flood has a one percent chance of occurring in any given year. It is sometimes referred to as the lO0-year flood, because it is the flood that would be equaled or exceeded on an average of one time.every one hundred years, measured over a long time period. CMR:220:98 Page 2 of 5 reconnaissance of the floodplain area to identify buildings, fences, and other obstructions that could affect the flow path of floodwaters. Although the flooding event of February 2-3, 1998 was not as large as the one percent flood that FEMA attempts to depict on the FIRM, Nolte also used the City’s mapping of the actual flood limits as a "reality check" of its theoretical analysis. Nolte’s analysis has produced a floodplain map that has relatively minor, yet substantive differences from FEMA’s preliminary map.- Nolte’s analysis results in a net change of 180 additional properties included in the San Francisquito Creek floodplain as compared to FEMA’s preliminary revised FIRM. The net change consists of 92 properties added to the floodplain and 106 properties removed from floodplain based on the updated analysis as well as an addition of 194 properties that were not identified in either analysis, but were subject to flooding the February 2-3, 1998 flood event. The table below summarizes the number of properties within the designated floodplain on each of the map versions: MAP VERSION Current Flood Insurance Rate Map 1350 (FIRM) FEMA’s preliminary revised FIRM 2150 Nolte’s floodplain map 2330 # OF PROPERTIES IN FLOODPLAIN Attachment A is an overlay of Nolte’s floodplain map vs. the current FIRM. Attachment B is an overlay of Nolte’s floodplain map vs. FEMA’s preliminary revised FIRM. Staffbelieves that there is a strong basis for a successful map appeal using Nolte’s mapping of the San Francisquito Creek floodplain because it is based on more extensive ground elevation data than FEMA’s preliminary revised FIRM. It also has a closer correlation with the actual flooding patterns that occurred on February 2-3, 1998. In an earlier report to Council, staffalso raised the issue that FEMA used a revised mapping policy to prepare the preliminary revised FIRM, and that this revision could possibly serve as another basis for a map appeal. Specifically, FEMA now maps all areas subject to flooding of any depth as compared to its prior policy of mapping only those areas subject to flooding in excess of one-foot deep. Nolte had extensive conversations with FEMA representatives as well as with its technical review consultant regarding its mapping policy, and determined that the policy has been adopted and implemented uniformly on a nationwide basis and is unlikely to be modified. Based on this practical reality, Nolte has advised against pursuing this issue as a basis for map appeal. CMR:220:98 Page 3 of 5 There are only minor differences between FEMA’s preliminary revised FIRM and Nolte’s mapping of the San Francisquito Creek floodplain. Therefore, if Council directs staff to file a map appeal, staff will refer to both maps when enforcing the flood-related special building requirements contained in Palo Alto Municipal Code Chapter 16.52. Unless otherwise directed, by Council, staff will begin to enforce the special building requirements for those properties that are within the designated floodplain on .both FEMA’s preliminary revised FIRM and Nolte’s floodplain map, since they will be included on the new FIRM regardless of FEMA’s response to the City’s appeal. The primary special requirement is that building floors must be constructed at or above the base flood elevation for all new construction or substantial improvements to existing structures. All building permit applications received after May 12, 1998 will be subject to this revised floodplain review policy. _Applications received prior to May 12, 1998 have been reviewed based upon the floodplain boundaries delineated on the current FIRM. The mandatory flood insurance requirement for newly mapped properties will not take effect until the final FIRM is published by the Government Printing Office approximately six months following resolution of the appeal. Related Map Changes Publication of a new FIRM also provides the opportunity for the City to correct other inaccuracies on the existing maps. Staff has previously submitted corrections to street names and layouts as part of the map revision process. In addition, staff previously submitted a revised boundary for the saltwater, flood zone, which corresponds with .the eight-foot elevation contour, based upon current elevation data from. the City’s GIS. The proposed zone boundary change represents a relatively minor revision from the current FIRM, but is a better reflection of the area at risk of flooding from San Francisco Bay. FEMA has not yet responded to this revision request, but staff expects it to accept the proposed changes. If approved, this change will result in a net decrease of 38 properties in the salt water flood zone (199 properties added to and 237 properties removed from the map). ALTERNATIVES TO STAFF RECOMMENDATION If Council decides not to submit an appeal of FEMA’s preliminary revised FIRM, staff will immediately begin using FEMA’s map as the basis for enforcement of the flood-related special building requirements. The mandatory flood insurance requirement for newly mapped properties will not take effect until the final FIRM is published by the Government Printing Office in approximately six months. POLICY IMPLICATIONS This report does not represent any change to existing City policies. TIMELINE If directed by Councilto submit an appeal of FEMA’s preliminary revised FIRM, staff will submit the appeal prior to the May 28, 1998 close of the formal appeal period. Staff expects to receive a response from FEMA within approximately 90 days from receipt of the City’s - appeal. A revised outline and timeline for the full map revision process is attached. CMR:220:98 Page 4 of 5 ENVIRONMENTAL REVIEW Council’s consideration of whether to appeal the revised Flood Insurance Rate Map is not a project for purposes of the California Environmental Quality Act (CEQA). ATTACHMENTS A - Overlay of Nolte’s floodplain map vs. the current FIRM B - Overlay of Nolte’s floodplain map vs. FEMA’s preliminary revised FIRM C - Outline of Map Revision Process PREPARED BY: Joe Teresi, Senior Engineer DEPARTMENT HEAD: ~ /~. ’~ GLENN S. ROBERTS Director of Public Works CITY MANAGER APPROVAL: ~NE FLEMING City Manager Ken Nauman, FEMA Ray Lenaburg, FEMA Kay Whitlock, Santa Clara Valley Water District Randy Talley, Santa Clara Valley Water District Ruben Nifio, City of Menlo Park Mahendar Chima, City of East Palo Alto Pat Showalter, San Francisquito Creek CRMP Coordinator Susan Frank, Palo Alto Chamber of Commerce Cathy Lehrberg, Crescent Park Neighborhood Association Kevin Fisher, Duveneck Neighborhood Association Raymond Hebert, St. Francis Neighborhood Association Warren Kallenbach, Community Center Neighbors Association Laura Alms, Peninsula West Valley Realtors Association John Paul Hanna CMR:220:98 Page 5 of 5 Attachment A Nolte and Associates’ San Francisquito Creek floodplain map VS. current FEMA Flood Insurance Rate Existing saltwater flood area ST [~ FEMA: Current FIRM freshwater flood !~ Nolte: Freshwater flood area nolte-current 4M{3y98 Attachment B Nolte and Associates’ San F rancisquito Creek floodplain map VS. FEMA’s proposed Flood Insurance Rate Map ST Existing saltwater flood area I~ FEMA: Proposed freshwater flood area ~ Nolte: Freshwater flood area nolte-fema 4May98