Flood Plain Management Annual Progress Report September 2014

Transcription

1 Flood Plain Management Annual Progress Report September 2014 Flood Plains in the City of Santa Cruz The City of Santa Cruz flood plains encompass the low-lying areas along the San Lorenzo River through central Santa Cruz, and uninhabited properties along Branciforte, Carbonera, Arana, and Moore Creeks. The developed flood plain covers those areas along the San Lorenzo River, which include over 9,890 residents and 2,101 commercial and residential structures with a total of 3,520 housing units. It is estimated that a 100 year flood could cause up to $1.3 billion in damage. The table below from the 2013 Local Hazard Mitigation Plan Update gives a more detailed breakdown of the uses in the central Santa Cruz flood plain areas. Page 1 of 10

2 To improve the flood protection in the Branciforte Creek and San Lorenzo River flood plains the City has undertaken a number of activities over the three decades. This report highlights these activities. Flood Hazard Mitigation Plan The City has adopted a Flood Hazard Mitigation Plan, which outlines the following activities: Zoning Regulations National Flood Insurance Program National Flood Insurance Program, Community Rating System Public Education and Awareness Flood Warning and Response Time Levee Improvement Project Levee Pump System Page 2 of 10

3 Annual Progress Report Zoning Regulations In 1986 the City adopted FEMA-mandated flood zone regulations which conformed to National Flood Insurance Program (NFIP) Standards. These regulations have been in place since that time and have been continuously implemented. In July of 2003, as a result of a Community Assistance Visit from the State of California Department of Water Resources, the City was requested to update its flood plain zoning regulations. On September 27, 2005, the City Council adopted the revised flood plain ordinance and submitted the ordinance to the Department of Water Resources. No changes have been made to the zoning regulations since the 2005 revision. National Flood Insurance Program In 1986 the City joined the NFIP and has been a participating member since that time. Now that the U.S. Army Corps of Engineers (Corps) has completed the initial phase of the levee improvement project, FEMA, in a letter to the City dated June 26, 2002, redesignated many of the areas in the FEMA A-11 Flood Zone to the FEMA A- 99 Flood Zone designation. These areas are more particularly shown on the attached map. The effect of this change is of significant benefit to the residents, businesses, and property owners in these areas. Flood insurance premiums for the FEMA A-99 Flood Zone are significantly lower than the previous FEMA A-11 Flood Zone. Depending on the property and amount of required flood insurance, the new rates are approximately 40% lower than those previously paid. In total, flood insurance premiums have dropped significantly. The NFIP Community Rating System has awarded the City of Santa Cruz a Class Seven rating, which further reduces the A-99 flood insurance rates by 5%. New buildings and improvements are no longer mandated to meet FEMA flood construction requirements, but may continue to do so depending on the wishes of the property owner. To implement these changes the City adopted Section for addition to the City s Zoning Ordinance s Flood Management Regulations. This Section removes the requirement for mandatory compliance with the FEMA construction requirements but requires an acknowledgment from permit applicants that this area is still considered a flood hazard area by FEMA and that they voluntarily choose not to undertake flood proofing. As of June 26, 2003 the A-99 FEMA flood insurance premiums are in effect for the entire A-99 Flood Zone. As such, all policyholders in this area can now benefit from the new lower flood insurance rates. Each year the City submits an annual report to FEMA on the A-99 Flood Zone. Currently, 2,269 parcels in the San Lorenzo River flood plain are required to carry FEMA flood insurance and pay a collective annual premium of $ 1,291,947. This figure does not include private placement flood insurance on commercial buildings, which is estimated to be in the range of $ ,000 in annual premiums. Page 3 of 10

4 National Flood Insurance Program, Community Rating System The City, as a Class 7-designated community continues to undertake the activities required to maintain a qualifying status in this program, which allows reduced flood insurance premiums for residents of the City of Santa Cruz. Public Education and Awareness Due to the significance of the A-99 flood insurance savings and the effect on new construction or rehabilitation of existing properties in the A-99 Flood Zone, the City undertook a number of public information activities in As part of this campaign a specific web page was developed, which continues to provide information on the A-99 Flood Zone. The website is located at: The site includes a PDF file showing the May 16, 2012 A-99 flood insurance map and the 2002 FEMA Letter of Map Revision. The City has also created an Emergency Storm Preparation Booklet and a new Emergency Storm Preparation Web Site that is on its website at: The booklet provides information on both storm preparation and protection and after actions. A copy of the booklet is attached. The web page also provides other storm emergency information. In addition the City of Santa Cruz continues to be a participant in the 211 system which supplements the 911 system during emergencies to provide support information and other assistance to residents who call with requests for non-emergency assistance during floods and other disasters. As part of the disaster planning process the City has now updated its Local Hazard Mitigation Plan, which was approved by Cal EMA and FEMA and adopted by the City Council on June 24, One feature of the current update is the addition of a section on sea level rise. Page 4 of 10

5 A copy of excerpts of this information is attached. The plan also contains a section on flooding which is also attached. Both items are on the City web page and available for public review, with the Local Hazard Mitigation Plan at this web site: Flood Warning and Response Time In 2003 the City installed Miltronic elevation gauges on the Soquel and Water Street bridges to help in more accurately monitoring flood flows as they pass through central Santa Cruz. These gauges have been calibrated and are now in operation. Additionally, four new warning levels have been established in concurrence with the operation of the new Milronic elevation gauges. In 2004 the City repainted the water levels on the Water Street bridge support. In 2007 the City, as part of the Countywide Emergency Operations Center, installed a new reverse system that can automatically call persons in certain areas to warn of dangerous conditions, such as flooding. The system was used during the 2009 fire season in other parts of Santa Cruz County and proved very successful in providing mass warnings on a timely basis. Most recently the system has been expanded to other emergency uses and now allows an interface where cell phone users can register to receive the emergency calls. See the attached screen shot of the new cell phone registration system. In September of 2010 the lead staff of the City s Emergency Operation Center (EOC) will conduct a collaborative series of meetings to review readiness, rollout new GIS standards for the EOC and reviews ICS and other forms and documents and test the existing systems. The City of Santa Cruz in 2010 initiated work with colleagues in County government and NOAA on making the City a Tsunami Ready community. This effort was recently begun and will be a Page 5 of 10

6 collaborative and public process through to its conclusion. It is anticipated sirens and other warning devices will be installed in tsunami impact areas to assist in instant alert of residents. In the fall of 2013 the City staff members held the annual winter flood threat assessment and readiness meeting with the Department Operations Center (Public Works, Water, Parks and Recreation). In addition, in response to a 2013 winter storm an analysis was conducted by the City s consulting hydrologist at ESA/PWA to determine if the peak river flow times between the Big Trees USGS water gage and the Downtown USGS water gage had shortened. Their finding was that the times had indeed shortened but, not as much as originally thought. The purpose for this study was that the observed 2013 winter storm had almost simultaneous rain intensities in Felton and Downtown Santa Cruz, rather than the past cases where the storm intensity increased as the storm clouds moved toward the Santa Cruz Mountains. The change in storm patterns that this storm seemed to display is one of the predicted causal effects of climate change. Levee Improvement Project 1989 to The City s San Lorenzo River Design Plan was adopted in 1989, and, since that time, the City and the Corps have worked cooperatively to seek Congressional authorization and construction appropriations for the needed flood control and restoration improvements. Components of the Plan included raising three bridges, raising the existing levee, and restoring a habitat along the entire river system. To date, the City has reconstructed and raised three bridges (Water Street, Soquel Avenue, and Riverside Avenue) and seismically retrofitted the Laurel Street Bridge. Construction has been completed on both phases of the levee-raising project, and the City and Corps are now continuing to work cooperatively on the maintenance manual for the new levee improvements. Due to the presence of the Tidewater Goby and Steelhead Salmon, each of which are endangered species, this work has proceeded slowly because of the necessity to coordinate with the National Marine Fisheries Service (Steelhead Salmon) and the U.S. Fish and Wildlife Service (Tidewater Goby). Due to the completion of the levee improvements FEMA has awarded the City an A-99 Flood Zone designation for the San Lorenzo River Flood Plain. A separate project was completed in 2004 that provided improved streambank stabilization for the portion of the riverbank adjacent to Laurel Street Extension and Third Street. Over the last eight years the City and Corps have been in discussions on preparation of a maintenance manual for the project. However, in the process of developing the maintenance manual the Corps has modified the method by which it will ultimately certify the project and has determined that the amount of required sediment removal in the project s final phase will need to be increased. As originally planned, the final phase would have involved the removal of approximately 60,000 cubic yards of sediment from the project river bed. Now, with the new rules adopted by the Corps, the amount of sediment to be removed has increased to approximately 250,000 cubic yards. In the process of developing the increased estimate it has been determined by Phil Williams and Associates, in coordination with the Corps, that a slight increase in the levee Page 6 of 10

7 heights of between three to twelve inches, depending on the specific levee reach, would eliminate the need to remove sediment and also be more cost effective. Most recently, the Corps has released Draft Technical Letter relating to Certification of Levee Systems for the National Flood Insurance Program. One requirement of the Draft Technical Letter will require a re-analysis of the planned final phase to determine what the requirements will be using the Risk and Uncertainty Methodology. The Draft Technical Letter requires that the Corps utilize the Risk and Uncertainty Methodology for all new levee certifications, whereas the current project was designed using the Deterministic Analysis. The Deterministic Analysis was used based on a 1997 waiver through which the Corps allowed the San Lorenzo Project to continue using the Deterministic Analysis Methodology. Draft Technical Letter has rescinded the 1997 waiver. To determine the effect of this change in methodology, the City retained the firm of Phil Williams and Associates to prepare a hydrologic analysis of the levee system using the Risk and Uncertainty Methodology. This analysis was completed in March of 2009 and presented to representatives of the Corps Sacramento District at a meeting held in April of The Corps subsequently prepared comments on the analysis and Phil Williams and Associates submitted responses to these comments in early July of From this analysis it appears that a levee raise will be necessary in two reaches of the flood control project. More work at that time required the hiring by the Corps of a new hydrologist in the Corps Sacramento District. The hydrologist was ultimately not hired in the Sacramento District and the project technical support was transferred to the San Francisco District, however the project management for the project remains in the Sacramento District. With this new technical support work again commenced on the analysis of the project using the Risk and Uncertainty Methodology. The first work product from this process has now been completed the Hydrology Update San Lorenzo River Basin Santa Cruz, California. An excerpt of this report is attached. On the legislative front the President s FY 2011 Energy and Water Appropriations Act (Corps of Engineers budget) did not include any funding for the San Lorenzo Project. However Congressman Sam Farr has prepared a request that the Energy and Water Appropriations Act include an appropriation of $300,000. As in past years the City is working with Congressman Sam Farr and Senators Boxer and Feinstein to secure an appropriation for the project in the Senate Energy and Water Appropriations Act. Additionally, the City requested that Senators Boxer and Feinstein include a supplement of $15 million to the San Lorenzo River Flood Control Project in the proposed 2010 Water Resources Development Act (WRDA). It now appears that the Senate will not pass the 2010 WRDA this year. Another issue is now nearer to resolution. In 1994 the Corps completed the Chief of Engineers Report to Congress, which outlined the necessary levee improvements for the San Lorenzo River Flood Control Project. Two of the required City of Santa Cruz components of this project were: 1) the replacement of the northern two lanes of the Water Street Bridge, and 2) the complete Page 7 of 10

8 replacement of the Soquel Avenue Bridge. These changes were necessary to allow the flood control levees to be raised as required by the Corps. The local costs of the two bridge projects were then to be counted as a real estate credit towards the local share of the project cost. The project was authorized by Congress in the 1996 Water Resources and Development Act. The City of Santa Cruz proceeded to meet the local responsibility with respect to the Water Street Bridge and Soquel Avenue Bridge. The City s bridge construction schedule was designed to meet the Corps levee construction schedule at that time Replacement of the northern two lanes of the Water Street Bridge Soquel Avenue Bridge was bid for construction. However, during the administration of President George H. W. Bush the Corps proposed to close the San Francisco Corps of Engineers District Office as a cost-saving measure. In anticipation of this closure, the San Lorenzo River Flood Control Project was transferred from the Corps San Francisco District to the Corps Sacramento District. This transfer caused a delay in the Corps construction schedule. As a result, the City/Corps Project Cooperation Agreement (PCA) was also delayed. Since the City had committed to construction contracts for the replacement of the two bridges it could not delay the construction of the Soquel Avenue Bridge until a Project Cooperation Agreement was prepared by the Corps City/Corps PCA signed. Current Corps authority allows real estate credit for bridges bid after the PCA is signed but not for bridges bid after Congressional Authorization but before the PCA is signed. The Corps has recognized the special circumstances of the San Lorenzo River Flood Control Project and has cooperated in efforts to gain Congressional authority to provide credit for the local share of the costs for the Soquel Avenue Bridge. The first Congressional Authorization providing credit for the local share of the costs for the Soquel Avenue Bridge was included in the FY 2002 Energy and Water Appropriations Act. However, after the Act was signed into law the Corps determined the FY 2002 language was not specific enough to allow crediting for the Soquel Avenue Bridge. Most recently the needed clarifying crediting language was included in the Omnibus Appropriations Act, Energy and Water Development and Related Agencies Appropriations, for FY The crediting process by the Corps using the new Congressional authorization has now begun and involves the preparation of a crediting report which has to be approved by the Corps Sacramento District, the Corps South Pacific Division, Corps Headquarters, the Assistant Secretary of the Army, Civil Works, and the Santa Cruz City Council. It is estimated that this process will take approximately one year and has progressed on this schedule. It is hoped this Page 8 of 10

9 process will be concluded in the fall of A final development this year has been the Corps development of a vegetation policy for flood control projects. In 1996 when Congress enacted the Water Resources Development Act (WRDA) of 1996 it included Section 202(g) which required the Corps of Engineers to develop a policy to recognize that there may be some instances where vegetation may preserve, protect or enhance natural resources and/or protect the rights of Native Americans. The Corps has spent the intervening fourteen years developing a policy in this area. In this attempt the Corps has prepared several papers, studies and other assorted documents. Based on this nearly decade and a half process the Corp posted a Notice in the Federal Register entitled Process for Requesting a Variance from Vegetation Standards for Levees and Floodwalls. The 1996 WRDA, Section 101(a) (5) also authorized the Corps of Engineers to construct improvements to the San Lorenzo River Flood Control Project which incorporated both flood control and habitat improvements. These improvements were constructed in two phases in 2000 and What was unique about the San Lorenzo River Flood Control improvements is that they were specifically designed to meet both habitat restoration and flood control objectives. To this end the levees were oversized to accommodate both trees and shrubs. The Corps proposed new Vegetation Standards do not provide any recognition of projects such as the San Lorenzo River Flood Control Project which were designed to incorporate vegetation. In addition, in order to maintain the existing levee vegetation the City will need to apply for a variance from the Corps. Based on the current available information the City prepared the two attached letters to the Corps of Engineers seeking an exemption from the proposed Vegetation Standards for the San Lorenzo River Project. City Staff has also prepared a series of other technical comments which more carefully define the proposed Vegetation Standards so that they recognize projects such as the San Lorenzo River Flood Control Project were vegetation was designed as part of the project. In the meantime the City is working with the Sacramento District Corps staff on preparing a vegetation variance request. Work on the variance was suspended in 2013 since a provision in the proposed Congressional Water Resources and Reform Act (WRRDA) directed the Corps to develop a new set of standards to evaluate the presence of vegetation on levees. WRRDA was subsequently passed by Congress and signed into law by the President and the Corps is now in the process of re-evaluating its levee vegetation standards. Most recently in June of 2014 the Corps completed a study of the San Lorenzo River Flood Control Project entitled, San Lorenzo River Project Performance Evaluation. The summary of this evaluation is as follows: This investigation determined that, at the time of the assessment, the existing project could safely pass the 1% flood and has received a positive evaluation for the purposes of determining National Flood Insurance Program rate maps. However, sediment deposition near the upstream end of the project may continue to decrease the capacity of the channel, to the point that the 1% flood cannot be safely passed, within the next 50 years. Raising the levees two feet at Sta (downstream of Highway 1) should provide sufficient flood protection for the next fifty Page 9 of 10

10 years. Raises could daylight at Sta and reach an elevation of 34.3 ft NAVD 88 at Highway 1. Total length of the raise would be 1500 feet. No levee raises are projected to be required elsewhere in the project area. This evaluation is an important step forward for the City in terms of the finding that the existing flood control project is adequate to handle, at present, a projected 100 year storm event. The next steps the Corps and City are taking involve determining how and what approach should be used to address the sediment deposition mentioned in the summary section above. Also the City is evaluating the steps necessary to seek FEMA certification of the project. Levee Pump System The City has continued to upgrade and improve the levee pump system which lifts the flood flows from the stormwater system over the flood control levees to the San Lorenzo River. In 2008 and 2009 the City installed a new back-up electrical generator to power Bixby Street Pump Station during flood-event electrical outages. Improvements were also completed on Pump Station 1A that services Downtown Santa Cruz. In period the City upgraded Pump Station 1B with a new back up electrical generator to power the station during flood-event electrical outages and also increased the size of the pump. During this period the city also replaced seven storm drain gravity outlets along the levee system and is in the process of replacing another four. Dry weather diversions were also constructed at Pump Stations 1A, 1B and A3. Each year the City continues to main the other aspects of the levee pump system as part of its annual stormwater maintenance system. Attachments: Flood Hazard Chapter of Local Hazard Mitigation Plan Excerpt of Corps of Engineers San Lorenzo River Project Performance Evaluation, June 2014 Page 10 of 10